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V. M. Antropov, D. A. Bugai, L. M. C. Dutton, M. Y. Gerchikov, E. J. Kennett, A. I. Ledenev, A. A. Novikov, V. Rudko, J. Ziegenhagen

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The views expressed in this report are those of the authors and do not necessarily reflect those of the European Commission

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V. M. Antropov1, D. A. Bugai2, L. M. C. Dutton3, M. Y. Gerchikov3, E. J. Kennett3, A. I. Ledenev4, A. A. Novikov5, V. Rudko6, J. Ziegenhagen7

1SSE Complex, Chernobyl, Ukraine 2Institute of Geological Sciences, Kiev, Ukraine 3NNC Ltd, Knutsford, UK 4KORO, Zheltiye Vody, Ukraine 5Technocentre, Slavutich, Ukraine 6ISTC Shelter, Chernobyl, Ukraine 7DBE, Germany

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(UURU%RRNPDUNQRWGHILQHG '2&80(17,668(5(&25' HQJLQHHULQJGRFXPHQWV

'RFXPHQW7LWOH Review and analysis of solid long-lived and high level radioactive waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone.

3URMHFW5HIHUHQFH DG Environment Project No B7-5350/99/51983/MAR/C2

Purposeof Issue : For Client’s review.

Security Class : (UURU%RRNPDUNQRWGHILQHG

Originator/ Issue Description of Amendment Checker Approver Date Author 01 First Draft for Client’s review M Gerchikov LMC Dutton S J Cripps 15.11.00

02 Minor Text Changes E Kennett LMC Dutton S J Cripps 18.01.01

(i) – 1 – A1 – 7RWDOQXPEHU Intro: Text Tables - Figures - Appendices RISDJHV (xxv) 183 H60

Previous issues of this document shall be destroyed or marked 683(56('('

© NNC Limited 2001

All rights reserved. No part of this document, or any information or descriptive material within it may be disclosed, loaned, reproduced, copied, photocopied, translated or reduced to any electronic medium or machine readable form or used for any purpose without the written permission of the Company

Distribution: Lucien Cecille, DG Environment; NNC EDMS; Leonid Tabachny, Ukrainian Ministry of Emergencies; authors

3050aJul00 Controlling procedure - QP11, QP40 'RFSURGUHI

NNC Limited C6033/TR/001 Issue 02 Page (i) 6XPPDU\ The study characterised potential waste arisings in the Exclusion Zone surrounding the Chernobyl Nuclear Power Plant. Studied sites include the Industrial Zone outside the Sarcophagus, three engineered disposal sites (the so-called PZRO), non-engineered near surface trench dumps (PVLRO), contaminated soil and sites of ‘unauthorised’ disposal within the Exclusion Zone.

Analysis of the previous methodology used for waste characterisation and inventory estimates identified a number of errors. A new database was established, which contains the most up-to date information on radwaste in the Exclusion Zone. Based on the analysis of the available information and potential radiological consequences, a judgement was taken regarding the priority of waste retrieval. In a number of cases it is necessary to carry out risk assessment to ensure that in-situ disposal would satisfy the Ukrainian regulations.

Assessments of waste stream volumes for subsequent incineration, encapsulation, storage and disposal in the planned near-surface facilities have been made. It is judged that throughput and capacity of the planned waste management facilities specified by OSAT is, in general, appropriate to the likely waste arisings.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (ii) 7DEOHRI&RQWHQWV

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 ,1752'8&7,21 1.1 OBJECTIVES...... 1 1.2 BACKGROUND ...... 1 1.3 SCOPE OF THE STUDY...... 5 1.4 ORGANISATIONS INVOLVED IN CURRENT STUDY ...... 6

 29(59,(:2)5(*8/$725<5(48,5(0(176211($5685)$&(',6326$/2) 5$',2$&7,9(:$67(  2.1 INTERNATIONAL GUIDELINES ...... 9 2.2 UKRAINIAN REQUIREMENTS ...... 9

 '(6&5,37,212):$67('8036:,7+,17+(&+133(;&/86,21=21( 3.1 INDUSTRIAL ZONE ...... 11  'HVFULSWLRQRI6LWH  0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV  :DVWHFKDUDFWHULVWLFV   $QDO\VLVRIUHOLDELOLW\RIGDWD  ,GHQWLILFDWLRQRIIXUWKHUDFWLYLWLHVUHTXLUHGWRLPSURYHGDWDTXDOLW\ 3.2 PZRO PODLESNY ...... 26  'HVFULSWLRQRI6LWH  0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV  :DVWHFKDUDFWHULVWLFV   $QDO\VLVRIUHOLDELOLW\RIGDWD  ,GHQWLILFDWLRQRIIXUWKHUDFWLYLWLHVWRLPSURYHGDWDTXDOLW\ 3.3 PZRO KOMPLEKSNY...... 39  'HVFULSWLRQRI6LWH  0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV   :DVWHFKDUDFWHULVWLFV   $QDO\VLVRIUHOLDELOLW\RIGDWD  3.4 PZRO BURYAKOVKA...... 49  'HVFULSWLRQRI6LWH  0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV   &KDUDFWHULVWLFVRIZDVWHGLVSRVHGLQ7UHQFKDW%XU\DNRYND  &KDUDFWHULVWLFVRIZDVWHGLVSRVHGDW%XU\DNRYNDDVDZKROH   $QDO\VLVRIUHOLDELOLW\RIGDWD   ,GHQWLILFDWLRQRIIXUWKHUDFWLYLWLHVWRLPSURYHGDWDTXDOLW\  )XWXUH3URVSHFWVIRU5DGLRDFWLYH:DVWH'LVSRVDODW%XU\DNRYND 3.5 GENERAL DESCRIPTION OF PVLROS ...... 67 3.6 SURVEYED PVLROS ...... 69  0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV   6HFWRURI39/525\]K\/HV   6HFWRUVDQGRI39/52³6WDQW]L\D

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (iii) 3.8 CONTAMINATED SOIL WITHIN EXCLUSION ZONE...... 104  'HVFULSWLRQRI6LWH  0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV   :DVWHFKDUDFWHULVWLFV  3.9 OTHER SOURCES OF WASTE WITHIN THE EXCLUSION ZONE...... 108  8QDXWKRULVHGGLVSRVDOVLWHV   5DVVRKDDQG  3.10 ANALYSIS OF RELIABILITY OF DATA FOR PVLROS, CONTAMINATED SOIL, MACHINERY AND UNAUTHORISED DISPOSAL SITES ...... 108 3.11 IDENTIFICATION OF FURTHER ACTIVITIES TO IMPROVE DATA QUALITY ...... 109

 $1$/<6,62)35,25,7,(6)25:$67(5(75,(9$/$1'5(0(',$7,212)7+( '8036 4.1 SOURCES OF CONTAMINATION...... 110 4.2 CORRESPONDENCE OF WASTE DISPOSAL WITHIN THE EXCLUSION ZONE TO INTERNATIONALLY ACCEPTED NORMS AND STANDARDS...... 117  ,$($6DIHW\*XLGHOLQHVIRU1HDU6XUIDFH'LVSRVDO   &RPSDULVRQRIZDVWHGLVSRVDOZLWKLQ([FOXVLRQ=RQHZLWK,$($5HFRPPHQGDWLRQV 4.3 QUALITATIVE ASSESSMENT OF THE COMPARATIVE RISKS TO THE PUBLIC ARISING FROM THE DUMPS 120  ([SRVXUHSDWKZD\V  ([SRVXUHRXWVLGH([FOXVLRQ=RQH   ([SRVXUHZLWKLQWKH([FOXVLRQ=RQH  6XPPDU\RIGRVHVIURPHDFKH[SRVXUHSDWKZD\ 4.4 PLANNED OR ONGOING ACTIVITIES WITHIN THE EXCLUSION ZONE IMPACTING ON RISKS ARISING FROM WASTE DUMPS...... 130  )XWXUHRSHUDWLRQVZLWKLQ,QGXVWULDO=RQH  )DFLOLWLHVSODQQHGDW6WUR\ED]D  5LJKW%DQN3URWHFWLYH'DP 4.5 PRIORITISATION OF WASTE RETRIEVAL...... 133 4.6 REMEDIATION OF WASTE DUMPS ...... 142

 ,03/,&$7,216)25:$67(0$1$*(0(17 5.1 BACKGROUND ...... 145 5.2 INDUSTRIAL COMPLEX, TREATMENT AND DISPOSAL FACILITY ‘VECTOR’ (CTD) ...... 146  *HQHUDO   (VWLPDWHVRIZDVWHDULVLQJVXVHGIRUVSHFLI\LQJ&7'   ,QIRUPDWLRQRQWKHSUHVHQWDSSURDFKWRZDVWHWUHDWPHQWFRQGLWLRQLQJDQGSDFNDJLQJ  5DGZDVWHGLVSRVDOVWRUDJH  0DQDJHPHQWRI///,/: 5.3 UPDATED WASTE INVENTORY AND INVENTORY COMPARISON ...... 164 5.4 IMPLICATIONS FOR MANAGEMENT OF LONG-LIVED WASTES...... 167  5HPRYDOVRUWLQJFRQWDLQHULVDWLRQDQGWUDQVSRUW   7UHDWPHQWDQGFRQGLWLRQLQJ   ,QWHULPVWRUDJHRIORQJOLYHGZDVWHV   &21&/86,216$1'5(&200(1'$7,216  6.1 CONCLUSIONS ...... 172 6.2 RECOMMENDATIONS ...... 175

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (iv) /LVWRI7DEOHV

Table 1: Involvement of organisations within current project Table 2. Details of contributions to the current report by Ukrainian companies Table 3: IAEA waste classification system [IAEA, 1994a] Table 4. Specific soil activity of the accident-related layer in the Shelter Local Zone [ISTC, 1998a] Table 5. Specific activity of post-accident man-made layer in the Shelter Local Zone [ISTC, 1998a] Table 6. Average soil contamination for Industrial Zone as a whole [OP ChNPP, 1998] Table 7. Categorisation of radwaste in Sectors of the Shelter Local Zone Table 8. Wastes in the Shelter Local Zone Table 9. Estimates of wastes from the Industrial Zone [OP ChNPP, 1998]. Table 10 Physical characteristics of waste disposed at PZRO “Podlesny” according to the Exclusion Zone Waste 1990 inventory register data (reflecting the status at the end of 1988) [SSE Complex, 1990a and 1990b]. Table 11 Radiation characteristics of radwaste, concentrated at the Disposal Station “Podlesny”, based on Kyiv Institute “Energoproekt” data (1987) [Energoproekt, 1995]. Table 12. Assessment of radionuclide activity of waste disposed at Podlesny for 01.01.2000, based on 1990 Exclusion Zone radioactive waste inventory register and on the ISTC “Shelter” data Table 13 Summary of data on characteristics of radioactive waste disposed at Podlesny Table 14. Physical characteristics of waste for the PZRO Kompleksny (based on the results of the survey conducted by STC "KORO", 1996) Table 15. Characteristics of waste disposed in the PZRO Kompleksny (for year 2000) Table 16. Physical characteristics of waste, disposed in Trench 25 at Buryakovka (according to State Specialised Enterprise "Complex" estimations) Table 17. Sources of radioactive waste disposed at Trench #25, Buryakovka (according to SSE "Complex" estimations) Table 18. Waste inventory for trench # 25 at Buryakovka (according to State Specialised Enterprise "Complex" estimations for years 1997-1999) Table 19. Correlation ratios (%) between the specific activity of long-lived radionuclides and Caesium-137 specific activity for the waste samples from trench #25 at Buryakovka (to year 1998) Table 20. Specific activities of radionuclides within the waste samples for trench #25, Buryakovka Table 21 Re-assessment of characteristics of waste disposed in Trench 25 at Buryakovka, using experimental correlation ratios (to year 1998) Table 22. Distribution of specific activity of waste batches in trench # 25, Buryakovka, according to the statistical distribution of exposure dose rate measurements.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (v) Table 23. Data on waste batches with measured dose-rates in access of 200 mR/h (equivalent to IAEA long-lived waste) in trench 25. Table 24. Characteristics of waste disposed at Buryakovka, as a whole (according to State Specialised Enterprise "Complex" data) (year 1998) Table 25. Waste inventory for Buryakovka, as a whole, as assessed by IGS based on data for Trench 25 (to year 1998) Table 26. Results of a preliminary radiation survey of motor and tractor machinery, temporally stored at an open-air site at Buryakovka, obtained by State Specialised Enterprise "Complex" (1999) Table 27. Surveyed and non-surveyed PVLRO sectors in the ChNPP Near Zone, as of year 2000 (data from STC “KORO”) Table 28: Surveys of PVLROs performed to date Table 29. Correlation coefficients for deriving activities of other radionuclides from 137Cs activity in Chernobyl fuel-type waste (for 1995) Table 30. Characteristics of waste in trenches and mounds in Sector 2.1, “Ryzhy Les” Table 31. Volume of waste in surface and near-surface soil layers in Sector 2.1, “Ryzhy Les” Table 32. Radiation characteristics of waste in trenches and mounds in Sector 2.1, “Ryzhy Les” (for year 1992) Table 33. Maximum dose rates and corresponding waste characteristics for three trenches in Sub-sector D-1 of Sector 2.1, Ryzhy Les (1992) Table 34. Physical characteristics of waste in disposal trenches in Sectors 3.1 and 2.3 of “Stantziya Yanov”. Table 35. Radiation characteristics of waste contained within the trenches in Sectors 3.1 and 2.3, “Stantziya Yanov” (Year 1993). Table 36. Physical characteristics of waste in trenches/mounds in PVLRO “Neftebaza” (Sectors 5.1, 5.2, and 5.3). Table 37. Volumes of waste in surface and near-surface soil layers in PVLRO Neftebaza (Sectors 5.1, 5.2, and 5.3) Table 38. Radiation characteristics of waste in trenches/mounds in Sectors 5.1, 5.2, and 5.3, “Neftebaza” (Year 1994-1995). Table 39. Physical Characteristics of Waste in trenches and mounds in PVLRO “Peschannoe Plato” Sector 6.0 Table 40. Radiation Characteristics of Waste in Trenches and Mounds in PVLRO “Peschannoe Plato” Sector 6.0 (1998) Table 41. Physical Characteristics of waste in trenches and mounds in PVLRO Sector 3.5 “Stantziya Yanov”. Table 42. Radiation characteristics of waste in trenches and mounds in PVLRO Sector 3.5 “Stantziya Yanov” (1999) Table 43. Summary of data on waste characteristics relating to surveyed PVLRO Sectors

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (vi) Table 44. Estimations of volumes and characteristics of waste in the unsurveyed PVLRO sectors of the ChNPP Near Zone Table 45. Characteristics of waste in surveyed region in vicinity of road, for PVLRO “Staraya Stroybaza”, 1996 [STC KORO, 1996a] Table 46. Estimated waste characteristics for PVLRO “Chistogalovka”. 1988 SSE Complex inventory data and calculated values for 01.01.2000. Table 47. Quantity and α–activity of TRU (Pu-238, Pu-239, Pu-240, Am-241, Cm-244) for contaminated soil in the ChNPP Exclusion Zone (Year 2000). Table 48. Characteristics of Sources of contamination within the Exclusion Zone, corresponding to year 2000. Table 49. Hydrogeological conditions in the vicinity of waste dumps within the Exclusion Zone (According to IGS data) Table 50. Reference levels for a minimum-engineered facility in the Exclusion Zone for house occupancy scenario Table 51. Summary of dose estimates from sources within Exclusion Zone for individual exposure pathways Table 52. Summary of prioritisation of waste dumps Table 53. Plan for establishing CTD Table 54. Volumes of radwaste for processing and disposal Table 55. Radwaste volumes after conditioning at CTD Table 56. Characteristics of LL-LILW located at PVLRO Table 57. Characteristics of repositories at CTD Table 58. Main specifications of personnel radiation protection during SRW disposal Table 59. Classification and acceptance criteria of surface SRW disposal Table 60. Estimates of waste stream volumes from the Exclusion Zone for LL-LILW Table 61. Estimates of waste stream volumes from the Exclusion Zone for SL-LILW Table 62. Waste stream volume estimates, m3 Table 63. Comparison of LL-LILW streams

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (vii) /LVWRI)LJXUHV

Figure 1 Location of PZROs Figure 2. Layout of PVLRO Sectors in ChNPP Near Zone Figure 3. Layout of ChNPP Industrial Zone Figure 4. Infrastructure of the Industrial Zone with proposed location of the waste management facilities Figure 5. Shelter Local Zone Figure 6. Contamination within the Industrial Zone Figure 7. Tasks required to categorise the waste at the Industrial Zone Figure 8 Layout of PZRO “Podlesny” Figure 9 Layout of PZRO “Podlesny” Site (based on VNIPIPT materials, 1990) Figure 10 Plan of concrete compartments at PZRO “Podlesny” Figure 11 Schematic of PZRO Podlesny, Compartment B-1 dating from December 1986. Figure 12 PZRO “Podlesny” (as viewed from the south-west) Figure 13. Map showing the location of PZRO Kompleksny. Figure 14. General view of PZRO Kompleksny prior to closure (reconstructed by STC "KORO" using an aerial photograph). Figure 15. Layout of the PZRO Kompleksny site [TACIS, 1995]) Figure 16. PZRO Kompleksny. Cross-section of radioactive waste compartments. Figure 17: General view of PZRO Kompleksny Figure 18: Depressions at the surface of PZRO Kompleksny Figure 19. Layout of Buryakovka site Figure 20. Cross-section of storage trenches at Buryakovka Figure 21. Loading of radioactive waste into trenches at Buryakovka [Chernobylinterform, 1996] Figure 22. Stages of capping a trench at PZRO Buryakovka. Figure 23. Aerial photograph showing location of PVLROs Figure 24. Trench and Mound layout at Sector 2.1 of “Ryzhy Les” (T=trenches, B=mounds) Figure 25. Current state of vegetation at Sector 2.1 of “Ryzhy Les” Figure 26. Layout of Sectors 2.3 and 3.1 of PVLRO “Stantziya Yanov” Figure 27. Surface flooding of PVLRO Neftebaza (Photographs taken April 1999) Figure 28. View of unfinished trench at PVLRO Neftebaza Figure 29. Layout of PVLRO Sector 6 “Peschannoe Plato” Figure 30. Aerial photograph of PVLRO Peschannoe Plato Figure 31. Location of PVLRO Staraya Stroybaza

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (viii) Figure 32. General view of Staraya Stroybaza Figure 33. Section of PVLRO “Staraya Stroybaza” surveyed in 1996 during the construction of a new road. Figure 34. View of surface of Staraya Stroybaza, with remnants of cementing solution applied to surface Figure 35. Layout of PVLRO Stantziya Semikhody (based on Scientific Technical Centre “KORO” data). Figure 36. Location of PVLRO “Novaya Stroybaza”, “Kopachi”, and “Chistogalovka”. Figure 37. Layout of PVLRO Chistogalovka. From the Research and Design Institute of Industrial Technology, 1990. Figure 38. Map of concentrations of alpha-emitting radionuclides in surface 10 cm of soil in the Exclusion Zone Figure 39 Locations of areas with concentrations of alpha-emitting radionuclides over 0.37 Bq/g Figure 40. Distribution of wetlands in the vicinity of ChNPP Figure 41. Scheme of Right Bank Protective Dam Figure 42. Logic of assigning categories A, B and C to waste dumps within the Exclusion Zone Figure 43. Waste stream flow chart. Volumes given in 1000 m3

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (ix) /LVWRIDEEUHYLDWLRQV

ChNPP Chernobyl Nuclear Power Plant CTD Chenobyl complex of facilities for treatment and disposal of wastes GBq Giga Becquerel = 109 Bq HLW High Level Waste IAEA International Atomic Energy Agency ICRP International Commission for Radiological Protection LL-LILW Long-lived Low and Intermediate Level Waste (IAEA classification) LILW Low and Intermediate Level Waste LRW Liquid Radioactive Waste OSAT On-Site Assistance Team PVLRO Site of temporary storage of radioactive waste (Russian abbreviation) PZRO Site of radwaste disposal (Russian abbreviation) SL-LILW Short-lived Low and Intermediate Level Waste (IAEA classification) SLLW Solid long-lived waste (IAEA classification) SPORO-85 Safety rules for radwaste management (1985) SRW Solid radioactive waste TBq Terra Becquerel, =1012 Bq TRU Transuranic elements

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (x) ([HFXWLYH6XPPDU\ 6XPPDU\RIWKH:RUNDQG5HVXOWV /RFDWLRQRIZDVWHDULVLQJV

Waste within the Chernobyl Exclusion Zone is currently present at the following locations:

1. Unit 4 of the Chernobyl Nuclear Power Plant (ChNPP) and the Object Shelter. These are not considered within the current study. 2. Wastes within the Shelter Industrial Zone, i.e. in the fenced area within the Shelter Industrial Zone, which surrounds Unit 4. 3. ChNPP Industrial Zone, including areas in the vicinity of Units 1-3. 4. PVLROs - so called ‘sites for temporary storage of radwaste’, which are surface trenches and mounds, into which waste was dumped after the accident. In some cases, the vegetation present on these sites should also be categorised as radioactive waste. 5. PZROs - so-called ‘sites for radwaste disposal’, which are engineered facilities and, as a rule, contain waste which is more active than that in PVLROs. 6. Contaminated soil – previously ignored as a source of waste. The majority of activity in the top 10 cm of soil is concentrated within an area of approximately 150 km2 with an α-activity of 0.37-20 Bq/g. 7. ‘Unauthorised’ disposal/storage sites – which are located throughout the Exclusion Zone. The identification of these sites and the categorisation and retrieval of the waste is an on-going activity. These sites contain metallic equipment dumped in an improvised tip, construction materials and other items. 8. Sediments of the Chernobyl Cooling Pond and water supply/drainage canals are outside the scope of this study.

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The Ukrainian definition of long-lived waste is currently being developed. The threshold for long-lived waste of 0.37 Bq/g for alpha-emitters, which is based on the Ukrainian regulation SPORO-85, was agreed with the European Commission and the Ukrainian Ministry of Emergencies as the value to be used in the present project. In practice, all wastes contained within PVLROs, PZROs and the Industrial Zone of the Chernobyl NPP fall into this category and have been considered within the current project.

Special attention has been paid to waste which is categorised as long-lived or high level according to the IAEA classification [IAEA, 1994a], since these wastes cannot be disposed in a near surface repository according to international guidelines. These wastes contain in excess of 400 Bq/g of long-lived alpha emitting radionuclides.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xi) &KDUDFWHULVDWLRQRIZDVWHZLWKLQ&K133,QGXVWULDO=RQH

Figure 1. Schematic of the ChNPP Industrial Zone

The whole area of the Industrial Zone (also termed ‘Promploshadka’, see Figure 1) is contaminated. However, only the Shelter Local Zone has been characterised to a reasonable level. Estimates for the remaining territory of the Industrial Zone were derived from the averaged data for the peripheral areas of the Shelter Local Zone.

The wastes are concentrated within the ‘accident related’ layer of soil that is some 30cm thick. The ‘post-accident man-made’ layer, which covers the ‘accident related’ layer and the underlying soil are also contaminated, but to significantly lower levels.

The Shelter Local Zone was decontaminated and bulldozed after the accident, with the radioactive waste being placed into metal containers. The containers (approximately 1700 altogether), with surface dose rates higher than 1Sv/h, were buried behind the Pioneer Wall next to the reactor building. These are not considered in detail within the current project, because a previous DG Environment study was dedicated to potential waste arisings from this site [DG XI, 1998].

The principal waste streams in the Local Zone have been identified as follows:

1. Containerised waste behind the Pioneer Wall (Reactor core fragments, ~600kg of nuclear fuel and other long-lived wastes belonging to groups II and III according to SPORO-85), 1700 m3

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xii) 2. Long-lived rubble, sand, gravel wastes (group III according to SPORO-85, 600 m3) 3. Long-lived concrete waste from the contaminated buildings (group III according to SPORO-85), 900 m3 4. Short-lived concrete waste from the contaminated buildings, lower activity levels (groups I/II according to SPORO-85), 137,000 m3 5. Metals, (dose rate at 10cm from the surface below 10 mSv/h) 1440 te 6. Short-lived soil waste (groups I/II according to SPORO-85), 139,000 m3

Overall the volumes of waste arisings have been estimated at 290,000 m3 within the Shelter Local Zone and 150,000 m3 elsewhere in the Industrial Zone.

The amounts of long-lived waste have been estimated to be 5300 m3 within the Shelter Local Zone and 250 m3 elsewhere in the Industrial Zone.

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Figure 2. Location of the PZROs Buryakovka, Podlesny and Kompleksny

The following PZROs are operated in the Exclusion Zone (see Figure 2): - PZRO “Buryakovka” - PZRO “Podlesny” - PZRO "Kompleksny" (also referred to as "Stage 3/ChNPP").

PZRO “Buryakovka” was commissioned in February 1987. It was intended for the burial of solid low and medium-level radioactive waste with suface gamma dose rates of less than 10 mSv/h and is still used for the disposal of waste originating from the Exclusion Zone.

Waste is contained in 26 near-surface trenches (140×60×4m3) on a clay foundation in unsaturated conditions with the provision for four further trenches at Buryakovka. It was found that PZRO “Buryakovka” contains some long-lived radioactive waste (according to the

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xiii) IAEA classification), which should not be disposed in near-surface facilities. The overall volume has been estimated to be 150 m3 (~0.03% of the total estimated for Buryakovka).

PZRO Podlesny includes 8 surface vaults, which consist of concrete walls made of pre-cast concrete and concrete blocks, installed on the shared concrete slab. The thickness of the walls is 1.12 m for the Type A vaults and 2.4 m for the Type B vaults. Only one vault of each type contains radioactive waste, to approximately one half of the total volume. The waste is long-lived, according to the IAEA categorisation system, with surface gamma dose rates ranging from 0.5 Sv/h to 2.5 Sv/h (data for 1986-1987).

The PZRO design was found to be defective and, as a result, the loading of radioactive wastes into the PZRO was stopped in 1988. The PZRO requires additional special measures for the provision of radiation safety. A preliminary design study, ensuring safe storage for 20 years, is being implemented by SSE Complex and Energoproekt. The total volume of waste is estimated to be about 4,000 m3.

PZRO "Kompleksny" was filled in 1986-1988 with LLW and ILW (Ukrainian Groups I and II), which are believed to be short-lived wastes according to the IAEA categorisation. It is located to the West of the cooling towers of the ChNPP Stage III.

The store has seven reinforced-concrete compartments, which are 6m wide, 5m deep and vary in length from 90 to 140 m. There are about 18,000 metal containers containing radioactive waste, each with a volume of 1m3, stored in this facility. In addition the store has been filled with unpackaged radioactive waste. Wastes at the bottom of the compartments are saturated since the groundwater table is 0.5-0.7 m above the foundation.

There is no information suggesting that long-lived wastes are present in this PZRO, but based on the relatively high average α-activity of waste (26 Bq/g), this cannot be altogether excluded.

The physical composition of waste within these PZROs is detailed below:

1. Buryakovka – soil, construction waste, concrete, metal from the Exclusion Zone 2. Podlesny – graphite, parts of the reactor core, construction waste from the Industrial Zone 3. Kompleksny – soil, construction waste from Unit 4 and the Industrial Zone

3=52 :DVWH  7RWDO $YHUDJHVSHFLILFDFWLYLW\ YROXPHP DFWLYLW\ RIZDVWH IRU 7%T β%TJ α%TJ Buryakovka 590,000 150 180 2.5 Podlesny 3,960 1000 123,000 1,800 Kompleksny 26,200 75 1,750 26

Table 1. Summary of data on waste within the PZROs Buryakovka, Podlesny and Kompleksny

A summary of the estimated inventory for these PZROs is presented in Table 1. They were derived within this study.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xiv) Although, at PZRO Buryakovka, wastes are characterised prior to disposal, the existing estimates of tje inventory where judged to be unreliable. Results of the detailed waste characterisation, which was recently implemented for Trench 25, were extrapolated for the whole of the repository.

The only sources of data on the inventory of waste within PZRO Podlesny are estimates by a Russian company VNIIAES and by the Ukrainian Institute Energoproekt [Energoproekt, 1995]. The latter work is based on the estimates by VNIPIET [VNIPIET 1991a and 1991b]. The methodology for both of these estimates is not presently available, but Energoproekt’s assessment could be ruled out since it suggested that the inventory is significantly larger than the estimates of the total activity present outside the Industrial Zone. VNIPIET’s estimates were used within the current project.

A number of γ dose-rate measurements within PZRO Kompleksny were taken in 1996. The inventory estimates in Table 1 are based on this investigation.

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Most of the area within the 5-km Near Zone to the North, West and South of the Chernobyl Nuclear Power Plant (ChNPP) Industrial Zone is occupied by PVLROs. Unpackaged waste is contained either within near-surface trenches or above-surface dumps without any engineered barriers.

The Near Zone is subdivided into Sectors, as shown in Figure 3. Only 28% of the area of the Near Zone has been reasonably well characterised in recent years. For the remaining sectors there are no reliable data available.

The 7 sectors that have been characterised to date are listed below:

1. Sectors 5.1, 5.2, and 5.3 (PVLRO Neftebaza) 2. Sectors 2.1 (PVLRO Ryzhy Les) 3. Sector 2.3, 3.1 and 3.5 (PVLRO Stantziya Yanov) 4. Sector 6 (PVLRO Peschannoe Plato)

The inventory for these sectors has been estimated based on measurements of the γ-dose rate within the dump, which were used to derive the activity of 137Cs (this radionuclide dominates the γ-emitting spectrum). As a result of this, the ‘radionuclide correlation ratios’ (contamination fingerprint) from waste samples were used to derive the inventory of the remaining radionuclides and the total α, β and γ –activities.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xv) Figure 3. Layout of the main PVLRO sectors within the ChNPP Near Zone

Radioactive waste within the PVLROs is concentrated within disposal trenches and mounds. The surface layers of soil over the entire area of the PVLROs are also contaminated. For the surveyed PVLROs, analysis of the data relating to soil contamination has been carried out for the surface soil layer (0-0.05m depth) and the near-surface soil layer (0.05 to 0.5 or 1m depth). Topsoil waste has been characterised only within sectors 2.1, 5.2 and 5.3 with the volumes in the others being estimated from the average volumes of waste per unit area within the surveyed sectors. A summary of the data for the characterised Sectors is provided in Table 2.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xvi)  39/526HFWRU Area, Ha :DVWHYROXPHP $YHUDJH VSHFLILF DFWLYLW\ RIZDVWH IRU β, Bq/g α, Bq/g Ryzhy Les, 2.1 Waste dumps 96 139,000 1030 16 Surface soil layer 96 44,000 268 4 Subsurface soil layer 96 17,000 1030 16 St Yanov, 3.1+2.3 Waste dumps 16 16,400 94 1 Surface soil layer 16 8,000 31 0.5 Subsurface soil layer 16 5,400 N/A N/A Neftebaza, 5.1+5.2+5.3 Waste dumps (5.1+5.2+5.3) 72 120,000 224 3.5 Surface soil layer - 5.2+5.3 32 14,000 112 1.8 Subsurface soil layer - 5.3 13 20,400 246 3.9 Peschannoe Plato Waste dumps 78 57,300 105 1.6 Surface soil layer 78 33,500 47 0.7 Subsurface soil layer - St Yanov, 3.5 Waste dumps 35 54,500 90 1.4 Surface soil layer 35 7,000 72 1.1 Subsurface soil layer 35 11,900 N/A N/A 7RWDO 

Table 2. Summary of data on characterised PVLRO sectors

It has been estimated that some 1,750,000 m3 of radwaste is contained within the uncharacterised sectors (cf 548,400 m3 in the characterised sectors), which are listed below:

1. Sectors 2.2-2.6 (PVLRO Ryzhy Les) 2. Sectors 3.2-3.4, 3.6, 3.7 (PVLRO Stantziya Yanov) 3. Sectors 1.1-1.4 (PVLRO Staraya Stroybaza) 4. Sector 1.5 (PVLRO Novaya Stroybaza).

Radwaste is also contained within the PVLROs Kopachi, Chistogalovka and Stantziya Semihody (Figure 4), which have not been assigned a sector number.

For these dumps, the inventory has been assessed using one of the three following methods:

1. By extrapolating the average contamination data from the neighbouring sectors (e.g Ryzhy Les, Stantziya Yanov) 2. By using available γ dose-rate measurements in a localised area (Staraya Stroybaza) 3. By using poorly documented estimates from a Russian institute VNIIAES, which date from the end of 1980s/beginning of 1990s (e.g. Chistogalovka, Kopachi).

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xvii)  39/52 $UHD+D :DVWHYROXPHP $YHUDJHVSHFLILFDFWLYLW\ LQFOXGLQJWRSVRLO RIZDVWH IRU β, Bq/g α, Bq/g Ryzhy Les 2.2-2.6, 305 610,000 100-1000 1.6 – 16 Stantziya Yanov, 3.2-3.4, 3.6-3.7 Staraya Stroybaza, 1.1- 186 484,000 100-1000 1.6-16 1.4 Stantziya Semikhody 45 167,000 100-1000 1.6-16 Novaya Stroybaza, 1.5 120 240,000 100 1.6 Kopachi 125 250,000 10-100 0.1-1 Chistogalovka 6 160,000 (free 10 <0.37 release?) 7RWDO 

Table 3. Summary of estimates for the uncharacterised PVLRO sectors

While there are little data on the composition of wastes, some estimates have been made by the Ukrainian experts responsible for the categorisation of the dumps. They estimate that the dumps mainly consist of the following:

- Soil (50-70%) - Rotted wood (20-50%) - Concrete/brick (~5%)

No heat-generating waste was found in any of the PVLROs. Two of them are believed to contain small amounts of long-lived waste according to the IAEA classification:

1. Sector 2.1 of Ryzhy Les PVLRO. SLLW contained within 3 trenches; the estimated overall fraction is 0.45%. 2. Sectors 1.1-1.4 of Staraya Stroybaza PVLRO. Although no firm data on the presence of long-lived wastes are available, the dump is likely to contain at least as much SLLW as Ryzhy Les due to its proximity to the Industrial Zone. The estimated overall fraction 0.45%.

Based on the available data, it is unlikely that other PVLROs contain long-lived waste. However, due to the scarcity of information, this cannot be ruled out completely.

Since the regional groundwater table is relatively close to the surface, waste in the majority of PVLROs is at least partly saturated. In some cases, the surface of the dumps is flooded either permanently or seasonally (e.g. the trenches of Neftebaza PVLRO, which are located in the Pripyat floodplain).

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xviii) Figure 4. Location of PVLROs Chistogalovka, Kopachi, Novaya Stroybaza and Stantziya Semihody

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Other sources of largely uncharacterised waste include:

- Approximately 100 ‘unauthorised’ sites with radioactive waste - Sites Rassoha 1 and Rassoha 2 with contaminated machinery - Soil outside the boundaries of the official disposal sites, which is contaminated to activity levels higher than the free release threshold.

For the majority of the ‘unauthorised’ sites, there is no information available other than their location. These wastes are being retrieved and re-disposed at PZRO Buryakovka. In 1999 Ukrainian operators (SSE Complex) retrieved some 37,000 m3 of these wastes, which comprised contaminated soil, destroyed structures and metal.

Approximately 30 helicopters and 3000 contaminated vehicles are stored at Rassoha 1 and Rassoha 2. The characterisation of the contamination levels of this machinery is currently ongoing. It is unlikely that any of these wastes will be characterised as long-lived according to the IAEA classification.

The very existence of PVLRO Pripyat, located in the area of Pripyat Town, is questionable. Some groups of Ukrainian scientists estimate that it covers 70 Ha with a waste volume per

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xix) unit area that is 10 times smaller than the average for the studied PVLROs. Others believe that there was no large-scale disposal in the area, although there are some dumps of contaminated household waste. The latter point of view seems to be supported by the fact that PVLRO Pripyat is not shown on maps of PVLROs dating from 1987 and 1992.

Contaminated soil is largely concentrated in the top 10cm of soil in the ‘Near Zone’ of the Exclusion Zone (radius ~5km from ChNPP). The current study estimated that the volume of soil, which should be classified as SL LILW, is in the region of 20 million m3.

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The objective of this task was to identify which radioactive wastes, must be retrieved in order to assess the volumes of waste streams for eventual treatment, conditioning, storage and disposal.

When making a decision on which wastes should be retrieved, it must be understood that

- Dumps and contamination in the Exclusion Zone are present in huge quantities over a large area. Conditions do not satisfy international guidelines for the near-surface disposal of radioactive wastes. However, contamination within the Industrial Zone, PVLROs, PZROs, soil and ‘Unauthorised Sites’ resulted either directly from the accident or from the subsequent clean-up work and the disposal recommendations are not always relevant.

- The entire removal of all contamination from the Exclusion Zone is not practicable in the foreseeable future. This is due to the huge resources that are required to manage the resulting waste streams safely and the potential damage that the removal of such a large volume of soil may cause to the environment.

- The implementation of a fully risk-based approach to prioritisation is not possible at the present time due to the high uncertainty regarding the level of contamination of some of the waste and the lack of a site-wide risk assessment for the Exclusion Zone. Although estimates for selected dumps and pathways are available in some cases, they are not adequate to either totally rule out or justify the retrieval.

Based on an extensive literature review and some evaluations of the doses to critical groups that were undertaken within the current study, it was concluded that

- At the present time, the highest potential doses to site operators or the public may result from the occasional ingestion of contaminated animals, birds or plants (mushrooms and berries) which have been in direct contact with contamination. External exposure is another factor that contributes significantly to personnel doses.

- Human intrusion, although unlikely in the present conditions, represents a significant long-term risk for dumps containing long-lived wastes, which would not decay to acceptable levels after the period of institutional control ends.

- There is no indication that either groundwater or atmospheric dispersion pathways are likely to result in the doses above the ICRP recommended constraint of 0.3 mSv/yr from a single source. A noticeable exception is the dose to firemen resulting from the inhalation of radioactive smoke in the event of a forest/bush fire over the dumps. These doses were

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xx) calculated to be comparable with the above limit. However, they would be significantly reduced if protective equipment were to be used.

Further, IAEA guidelines state that long-lived wastes must not be disposed of in a near- surface repository, that radioactive wastes should be isolated from the biosphere and that surface flooding/erosion of the disposal facility should not occur at frequent intervals [IAEA 1994a, 1999].

The sites where are wastes present within the Exclusion Zone have been assigned to one of the following three categories:

A. Waste retrieval is required as soon as possible following the completion of remedial option studies and detailed safety assessments. B. Waste retrieval is required prior to the termination of institutional control. Storage is only possible for as long as conditions are considered safe. A detailed risk assessment of the site and remedial option analyses are required. C. Further study of the radiological risk from the site and remedial option analyses are needed to determine whether waste retrieval is required. Waste disposal at the site may be possible following remediation, providing the conditions comply with international and Ukrainian requirements for near surface disposal.

The results of the categorisation are provided in Table 4. Although these recommendations are based on the most up-to date information available, additional characterisation of the wastes, a risk assessment and the analysis of the possible remedial options are required prior to taking the final decision on waste retrieval.

The principal reasoning behind the above recommendations for waste retrieval are as follows:

- Industrial Zone. Significant construction work is planned within the Industrial Zone. Further, in the current conditions, the wastes are not isolated from the biosphere. There is a significant presence of long-lived wastes (estimated ~2% - 5000 m3 in the Local Zone)

- PZRO Podlesny. All waste is presently categorised as long-lived (IAEA). Fortification of the existing facility is planned to ensure safe interim storage of waste in the current location.

- PZRO Buryakovka. There is long-lived waste in a near-surface facility. About 0.026% of the waste is categorised as long-lived. Contaminated machinery is exposed to the biosphere although, because the site is fenced and guarded, the situation is better than with other dumps that contain contaminated equipment.

- PZRO Kompleksny. The storage conditions of the waste at the PZRO do not comply with IAEA recommendations (e.g. the formation of holes resulting from settlement). In addition, water is present in this PZRO. Although there is no evidence that long-lived waste is present at Kompleksny, there is a relatively high average concentration of α- emitters (26Bq/g)

- PVLRO Staraya Stroybaza. Approximately 30% of the area will be affected by the planned construction of infrastructure associated with new Shelter (Sarcophagus). Long- lived wastes also must be retrieved.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xxi) - PVLRO Neftebaza. Today’s storage conditions do not comply with IAEA recommendations: Waste located within the Pripyat floodplain is permanently or seasonally flooded. However, this PVLRO was assigned category C, because there are plans to build a dam, which should remove flooding from this area.

6LWH 6HFWRU 7\SHRIGLVSRVDO RIZDVWHYROXPH LQHDFK&DWHJRU\ $% & Industrial Zone Man-made soil layers 100 PZRO Podlesny Engineered dumps 100 PZRO Buryakovka Trenches 0.03 99.97 Contaminated machinery 100 store PZRO Kompleksny Engineered dump 100 PVLRO Staraya 1.1-1.4 Waste dumps, top soil 29 70.7 Stroybaza PVLRO Neftebaza 5.1-5.3 Waste dumps, top soil 100

PVLRO Ryzhy Les 2.1 Waste dumps, top soil 0.5 99.5 2.2-2.6 Waste dumps, top soil 100 PVLRO Stantziya 3.5 Waste dumps, top soil 100 Yanov 2.3, Waste dumps, top soil 100 3.1-3.4, 3.6-3.7 PVLRO Peschannoe 6 Waste dumps, top soil 100 Plato PVLRO Stantziya Waste dumps and top 100 Semikhody soil PVLRO Novaya Waste dumps and top 100 Stroybaza soil PVLRO Kopachi Waste dumps and top 100 soil PVLRO Pripyat Waste dumps and top 100 soil PVLRO Waste dumps and top 100 Chistogalovka soil Soils Top soil 100 Unauthorised dumps Various 100 Rassoha 1 & 2 and Contaminated machinery 100 other contaminated machinery

Table 4. Prioritisation of waste retrieval

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xxii) - PVLRO Ryzhy Les. Long-lived wastes (IAEA) should be retrieved. Further assessments are required to determine whether waste should also be retrieved from the areas that are subjected to seasonal flooding.

- Rassoha 1 and 2, other contaminated machinery. The storage conditions do not comply with IAEA recommendations: contaminated machinery is exposed to the biosphere.

- Unauthorised dumps. The storage conditions do not comply with IAEA recommendations (exposure to the biosphere). Lack of information on location of these dumps poses a particular threat.

For the other dumps and contaminated soil, it was judged that remedial measures (such as the removal of the present vegetation and capping) may bring compliance with international recommendations and reduce the risks of potential exposure from the most significant pathways. A further risk assessment with consideration of all feasible Features, Events and Processes (FEPS) is required to demonstrate that the Ukrainian and International dose constraints will not be exceeded.

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It is necessary to complete the process of bringing the Ukrainian waste categorisation system in line with IAEA guidelines.

With disposal at Buryakovka still on-going, there is an urgent need to modify the existing acceptance criteria so that wastes with specific α-activity above 400Bq/g cannot be disposed in the near-surface trenches. This waste should be stored in above-surface facilities.

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There is a need to characterise the waste in those locations where a lack of data results in unacceptable uncertainty.

A further assessment of doses is required to identify the need for retrieval, when disposal conditions are not in obvious contradiction to the basic disposal guidelines (e.g. in the case of long-lived waste) or are not justified by the need for construction work. The assessment should verify compliance (or not) with the regulatory dose constraints for the institutional and post-institutional control periods.

Risk and safety assessments are also required for those sites where the retrieval of waste is recommended, including

• the interim storage period • doses incurred during the waste handling operations

Areas within PVLROs Neftebaza, Ryzhy Les, Stantziya Yanov and a significant proportion of contaminated soil, which are permanently or seasonally flooded by surface water, represent an area of particular concern. This is because it may be difficult to isolate these

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xxiii) dumps from the biosphere. Exposure via the ingestion of water-nesting fowl (e.g. ducks) deserves special attention.

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Wastes must be retrieved from the following sites:

• Industrial Zone – in line with the schedule of construction of a new sarcophagus • PZRO Podlesny – prior to termination of institutional control • PZRO Buryakovka (long-lived and machinery only) – before the end of institutional control • PZRO Kompleksny – as soon as possible • PVRLO Ryzhy Les (long-lived only) – as soon as possible • PVLRO Staraya Stroybaza (area affected by construction and long-lived waste) • Unauthorised dumps, including Rassoha – as soon as possible

For the remaining dumps, vegetation at the surface should be removed. The dumps should be fenced and capped to ensure isolation from the biosphere and to decrease the risk of human intrusion. Fortification of the structure for PZRO Podlesny must be undertaken to ensure the safe storage of long-lived wastes in situ in the short-term. Whenever possible, measures, such as construction of flood defenses, should be undertaken to remove flooding of the dumps and contaminated soil.

It is necessary to verify the presence of combustible long-lived wastes in the dumps. An additional facility for mixing combustible long-lived low and intermediate level waste (LL-LILW) with waste of a low activity containing only insignificant amounts of long-lived waste, with the aim to decrease the activity level of the mixed waste below 370 Bq/g, should be considered. In this way mixed waste could be incinerated at the planned incineration facility at the CTD in accordance with the Ukrainian safety requirements. It will also be necessary to ensure that annual discharge limits are not exceeded.

Immobilisation methods, such as the cementation of ashes and embedding into cement, suitable to prevent radionuclide migration during normal operation and in the event of accidents, should be considered. The methods and degree of LL-LILW immobilisation should be based on a safety assessment of the long-term storage at the CTD facility.

The planned waste management concept for the Complex for the Treatment and Disposal of Wastes (CTD, also referred to as Vector) generally complies with the requirements resulting from the updated waste streams. From the available information it is judged that the throughput of the incineration and compaction facilities will be adequate to process considered waste arisings from the Exclusion Zone. The current specification of the incinerator does not allow processing of long-lived wastes and thus presents a potential problem.

The planned disposal capacity for short-lived wastes was estimated to be excessive, but only if waste is not retrieved from the dumps currently identified for future risk assessment. It should be noted that the present degree of uncertainty is such that it is possible for the currently planned disposal capacity for short-lived wastes to be insufficient. This will depend on whether the disposal in some of the existing dumps can satisfy Ukrainian operational and post-closure individual dose constraints.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xxiv) All long-lived wastes from the areas of the Exclusion Zone which are considered within the current study, are likely to be contained within a single SRW-3 type store of specified capacity (13,000 m3).

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page (xxv)  ,QWURGXFWLRQ

 2EMHFWLYHV The objectives of the study are:

- to review and analyse all the potential sources of solid, long-lived waste (SLLW) and high-level waste (HLW) that exist in the Exclusion and Industrial Zones in order to define the technical specifications for the facilities for the radioactive waste treatment, conditioning, packaging, storage and disposal to be constructed later; - to establish a database.

The European Commission has recently issued a call for tenders for the Solid Waste Management facilities at the Vector site within the Exclusion Zone. These facilities were specified by the On-Site Assistance Team (OSAT) to include cementation, incineration and compaction plants as well as several types of near-surface disposal facilities. The ‘Vector’ Complex, also termed ‘Complex for Treatment and Disposal –CTD’ will accept the following waste arisings:

- from the operation and decommissioning of Units 1-3; - from Unit 4, resulting from the construction of the New Shelter; - from the operation of other nuclear power plants in the Ukraine; - from research and medical facilities in the Ukraine; - from the decommissioning of dumps in the Industrial Zone of ChNPP and the Exclusion Zone.

The latter waste stream is studied within the current project.

Due to its timing, the study cannot influence the specification of the solid waste management facilities identified by OSAT. However, these represent only the first phase of the planned waste management complex.

A new national programme for the next ten-year period is being prepared in the Ukraine. All state funding will be in line with this national programme. The priorities of work for the Chernobyl Exclusion Zone are high on the agenda of the programme, and the timing of the current project is such that the results gained will be taken into account.

 %DFNJURXQG The Chernobyl Exclusion Zone is defined as that area which is under the responsibility of the Administration of the Ministry of Chernobyl Affairs. The Exclusion Zone extends over an area of approximately 200,000 Ha and was contaminated as a result of the accident at Unit 4 in 1986.

Waste within the Chernobyl Exclusion Zone is currently present in the following locations:

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 1 1. Unit 4 of the Chernobyl Nuclear Power Plant (ChNPP), also termed ‘Object Shelter’ or ‘Unit Shelter’, which is not considered within the current study; 2. Wastes within the Local Zone of the ChNPP, i.e. in the fenced area within the Shelter Industrial Zone which surrounds Unit 4; 3. ChNPP Industrial Zone, including Shelter Industrial Zone and areas in the vicinity of Units 1-3; 4. PZROs which are engineered disposal facilities; 5. PVLROs which are the so-called ‘sites of temporary storage of radwaste’; 6. Contaminated soil; 7. ‘Unauthorised’ disposal/storage sites which are located throughout the Exclusion Zone. 8. Sediments of the Chernobyl Cooling Pond and water supply/drainage canals are outside the scope of this study.

There are three engineered storage facilities within the Exclusion Zone: PZRO Podlesny, PZRO Kompleksny and PZRO Buryakovka (Figure 1). The waste within the PZROs is contained within engineered trenches or concrete compartments. The radioactive wastes concentrated in the PZROs largely originated from the Near- accident Zone (radius of 3-5km) and have a characteristic radionuclide composition, which is close to that of the irradiated fuel at ChNPP Unit 4 at the time of the accident. PZRO Buryakovka is still currently being operated as a waste disposal facility. The other two PZROs were closed at the end of 1988.

The following PVLROs are located within the Exclusion Zone (Figure 2):

1. Staraya Stroybaza, Sectors 1.1-1.4 2. Novaya Stroybaza, Sector 1.5 3. Ryzhy Les, Sectors 2.1, 2.2, 2.4-2.6 4. Stantziya Yanov Sectors 2.3, 3.1-3.7 5. Neftebaza Sectors 5.1-5.3 6. Peschannoe Plato Sector 6.0 7. Stantziya Semikhody 8. Kopachi 9. Pripyat 10. Chistogalovka

PVLROs are temporary waste dumps that were created in-situ during the decontamination work performed in 1986-87 by the civil defence troops following the Unit 4 accident. The waste dumps were located without regard to the local hydro- geological conditions and contain no engineered barriers to prevent the spread of contamination. With the exception of PVLROs Pripyat and Chistogalovka, the waste dumps are located within the Near-accident Zone. Contamination of this area is largely associated with the fall-out of finely dispersed nuclear fuel particles from Unit 4.

Contaminated soils within the Exclusion Zone vary from long-lived waste, according to the IAEA classification system (see Section 2), to that below the level of free release. The most contaminated area is that in the immediate proximity to Unit 4, caused by the fallout of fragments of the reactor core and fuel particles. This area, the Shelter Local Zone, was decontaminated and bulldozed after the accident. The Shelter

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 2 Local Zone lies within the Industrial Zone, which is the fenced area surrounding the ChNPP (Figure 3).

The identification of unauthorised waste dumps and the categorisation and retrieval of waste from these sites is an on-going activity.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 3 )LJXUH/D\RXWRI39/526HFWRUVLQ&K1331HDU=RQH

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 4 )LJXUH/D\RXWRI&K133,QGXVWULDO=RQH

 6FRSHRIWKHVWXG\ The current study provides information and data on the following items:

- the place of arising of SLLW and HLW in the Chernobyl Exclusion Zone; - the characteristics of the waste products stored or dumped including their possible packages; - the deterioration with time of the different waste types in store; - the quantification of the volumes of SLLW and HLW; - the physical properties and composition of SLLW and HLW; - the specific activity of SLLW and HLW; - the spectrum of radionuclides associated with each waste type; - the qualitative assessment of doses incurred via the most important pathways; - the expected volumes of waste arisings from the retrieval of waste in the Chernobyl Exclusion Zone; - the impact of these waste arisings on the planned waste management facilities.

The Ukrainian definition of long-lived waste is currently being developed. The threshold for long-lived waste of 0.37 Bq/g for alpha-emitters, which is based on SPORO-85, has been used, as agreed with the European Commission and the Ukrainian Ministry of Emergencies. In practice, all wastes contained within PVLROs, PZROs and the Industrial Zone of Chernobyl NPP fall into this category and have been considered within the current project.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 5 Special attention has been paid to waste which should be categorised as long-lived or high level according to the IAEA classification [IAEA, 1994a] since these wastes cannot be disposed in a near surface repository according to international guidelines. These wastes contain in excess of 400Bq/g of long-lived alpha emitting radionuclides.

Section 2 of the report provides an overview of the Ukrainian regulatory requirements and the IAEA (International Atomic Energy Agency) recommendations in relation to the near-surface disposal of radioactive waste. The definition of long-lived waste according to Ukrainian and IAEA requirements is specified.

Section 3 of the report contains a description of the waste dumps within the Chernobyl Exclusion Zone including, a summary of the methods of data acquisition and analysis, a description of the physical and radiation characteristics of the waste and a critical analysis of the reliability of the data, for each of the waste dumps.

Section 4 provides a quantitative assessment of risks from the waste dumps. Waste disposal at the individual dumps is compared with international guidelines on near- surface disposal of radioactive waste. A preliminary estimation of doses to the public from the waste dumps via the most significant exposure pathways was made. The dumps were prioritised according to the associated risks and those dumps for which waste retrieval is required as soon as possible were identified.

Section 5 gives a description of the implications for waste management. A general description of the Vector waste management complex and an overview of the Ukrainian regulatory requirements for radioactive waste management applicable to the Vector complex are provided. The waste streams arisings from the waste dumps within the Chernobyl Exclusion Zone are identified along with the implications for waste sorting, transportation, treatment, conditioning and storage.

Appendix A details the methods used to acquire and analyse the data relating to the waste characteristics of the dumps. Appendix B contains a layout of the waste dumps in the ChNPP Civil Defence Troop Zone based on 1987 data. Appendix C provides the derivation of the formula used to calculate waste activity from measurements of exposure dose rate for Buryakovka. Data on the radionuclide composition of samples taken from waste batches to be disposed at Buryakovka are shown in Appendix D. Analysis of the current acceptance criteria for Buryakovka is presented in Appendix E. Appendix F gives the 1998 PVLRO and PZRO inventories according to State Enterprise Complex data. The location of the PVLROs based on 1992 data from the Research and Design Institute of Industrial Technologies is shown in Appendix G. Finally, Appendix H contains a report on the hydrological conditions and radioactive contamination of groundwater in the vicinity of the waste dumps within the Exclusion Zone.

 2UJDQLVDWLRQVLQYROYHGLQFXUUHQWVWXG\ The organisations that have participated in the preparation of this report and the details of their involvement are provided in Table 1.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 6 &RPSDQ\ 'HWDLOVRILQYROYHPHQW NNC Ltd (UK) Project management, technical coordination, review and checking of data, preparation of the final report, qualitative assessment of risks and prioritisation of retrieval, preparation of conclusions IGS (Ukraine) Coordination of Ukrainian companies, verification of the (Manager S P Dzhepo, levels of contamination, and radwaste volumes, provision of technical coordinator D information on groundwater contamination and risks, A Bugai) review of conclusions SSE Complex (Ukraine) Provision of information on measurement methodology, the (Manager V V Zhilinsky, data on volumes, characteristics and inventory of the technical coordinator V radwaste for PZROs Buryakovka, Podlesny, Kompleksny M Antropov) and for the unauthorised dumps STC KORO (Ukraine) Provision of information on measurement methodology, the (Manager A I Ledenev, data on volumes, characteristics and inventory of the technical coordinator P radwaste for PVLROs A Ovcharov) ISTC Shelter (Ukraine) Provision of information on measurement methodology, the (Manager V V Sherbin, data on volumes, characteristics and inventory of the technical coordinator V radwaste for the Industrial Zone. Analysis of waste streams M Rudko arising from construction activities within the Industrial Zone. Technocentre (Ukraine) Provision of information on radwaste management facilities (Manager V V planned for construction in the Chernobyl Exclusion Zone Tokarevsky, technical coordinator A A Novikov) DBE (Germany) Checking of information on radwaste management facilities J Ziegenhagen planned for construction in the Chernobyl Exclusion Zone. Analysis of the impact that new data will have on these facilities IRZ ATN (Ukraine) Analysis of the relevant Ukrainian regulations V B Berkovsky UNIISHR (Ukraine) Provision of information on measurement methodology, the V A Kashparov data on volumes, characteristics and inventory of the radwaste for contaminated soils. UNIISHR (Ukraine) Verification of inventory estimates methods at PZROs V A Levchuk Buryakovka and Kompleksny The Ukrainian Minstry of Provision of information on the Ukrainian regulations. Emergencies Review and commenting on the final report and other L Tabachny, documents N I Proskura

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The Ukrainian companies involved in the preparation of the current report have extensive relevant experience in the Chernobyl Exclusion Zone. Their experience and relevant responsibilities are listed below:

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 7 - Institute of Geological Sciences (IGS) – carried out a number of sampling and monitoring programmes at Ryzhy Les and other dumps in the Exclusion Zone. Modelled contamination of groundwater in the Near Zone. - SSE Complex – current operators of the PVLRO and PZRO dumps in the Exclusion Zone. Support official Ukrainian databases on contracts from the Ministry of Emergencies and Exclusion Zone. - STC KORO – implemented the characterisation of all the PVLRO sectors that have been studied to date and of PZRO Kompleksny. Prepared preliminary designs for the waste management facilities in the Exclusion Zone. - Interdisciplinary Science and Technology Centre (ISTC) Shelter – implemented characterisation of waste in the Industrial Zone. - Technocentre (Ukraine) – Ukrainian subcontractor of OSAT, who participated in specifying the radwaste management facilities in the Exclusion Zone. - The Ukrainian Ministry of Emergencies and Exclusion Zone – Ukrainian Government Ministry, responsible for safe operation of dumps in the Exclusion Zone.

Information provided by the Ukrainian companies was submitted in the form of reports, which were incorporated into the current document as detailed in Table 2.

5HIHUHQFH 6HFWLRQLQWKHUHSRUW IGS (1999). Sections 3.2-3.6 ISTC (2000). Sections 3.1 and 5.1 Ovcharov et al (2000). Section 3.6 Skalsky et al (2000). Section 4 Kashparov et al (2000). Section 3.8 Levchuk (2000). Sections 3.2-3.7 Antropov et al (2000a and 2000b). Section 3.4 Ledenev et al (2000). Section 3.4 Bugai et al (2000) Section 3.7 Novikov (2000). Section 5

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 8  2YHUYLHZRI5HJXODWRU\5HTXLUHPHQWVRQ1HDU6XUIDFH'LVSRVDORI 5DGLRDFWLYH:DVWH  ,QWHUQDWLRQDOJXLGHOLQHV The classification of radioactive waste according to the IAEA guidelines is shown in Table 3.

7DEOH,$($ZDVWHFODVVLILFDWLRQV\VWHP>,$($D@ :DVWHFODVV 7\SLFDOFKDUDFWHULVWLFV 1 Exempt waste Activity levels at or below clearance levels which are based on an annual dose to members of the public of less than 0.01mSv 2 Low and intermediate Activity levels above clearance levels for exempt waste and level waste (LILW) thermal power below about 2kW/m3 2.1 Short-lived Restricted long-lived radionuclide concentrations (limitation of long-lived alpha emitting radioisotopes to 4000Bq/g in individual waste packages and to an overall average of 400Bq/g per waste package) 2.2 Long-lived Long-lived radionuclide concentrations exceeding limitations for short lived waste 3 High level waste Thermal power above about 2kW/m3 and long-lived radionuclide (HLW) concentrations exceeding limitations for short-lived waste

According to the IAEA Safety Guidelines, near surface disposal is an option for disposing of short-lived low and intermediate level waste (SL-LILW) [IAEA, 1994a]. The ICRP has recommended that the appropriate risk constraint for members of the public for a near surface repository is 0.3 mSv/y [IAEA, 1999]. For the human intrusion pathway the ICRP recommended dose constraint is 10 to 100 mSv/y [ICRP, 1998].

General guidelines in relation to near-surface disposal of radioactive waste are specified in IAEA, 1994b & 1999. These include the requirement that a near surface disposal system should provide adequate isolation of radionuclides from the biosphere and that surface processes such as flooding, landsliding or erosion should not occur with such frequency or intensity that they could affect the ability of the disposal system to meet safety requirements (see Section 4.2 for details).

 8NUDLQLDQUHTXLUHPHQWV According to Ukrainian requirements it is prohibited to dispose of long-lived waste in a near surface disposal facility.

The system of classification of radioactive waste within the Ukraine is currently being developed. The Ukrainian Law defines long-lived wastes as those, which will exceed the free release levels in 300 years time.

The radwaste management regulations dating from the Former Soviet Union [SPORO, 1985, and OSP, 1987] specify the free release limits for wastes containing transurainc radionuclides as follows: - 2E-7Ci/kg (10 Bq/g) overall

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 9 - levels for alpha-emitting radiounuclides restricted to 1E-8Ci/kg (0.37 Bq/g)

Since the alpha-activity of the wastes in the Exclusion Zone will not change significantly over a 300-year period, the regulations pose an overly rigorous threshold for long-lived waste of around 0.37 Bq/g for the present-day activity of alpha- emitters. Wastes exceeding this threshold have been considered within the current study.

Another approach to classification based on activity, which is closer to the IAEA Regulations, is also currently being discussed in the Ukraine [Draft of National Standard of the Ukraine, 1999].

On the 6th of March 2000, additional regulations on waste acceptance criteria for the near-surface disposal of radioactive waste were introduced by the Chief State Doctor of the Ukraine [Ukrainian Hygienic Regulations, 2000]. These regulations define the dose constraint to members of critical groups from a repository as

- 0.04mSv/yr during the period of institutional control and - 0.01mSv/yr after the period of institutional control.

These are approximately one order of magnitude more rigorous than ICRP recommendations on individual dose constraint for nuclear facilities of 0.3 mSv/yr, which are accepted in most countries of the European Union.

For ‘abnormal’ natural events (such as earthquakes) and human intrusion, the document introduces dose reference levels A and B, which are equal to 50 mSv/yr and 1 mSv/yr respectively. It is stated that if estimated doses from a near-surface repository to members of critical groups after 300 years

- exceed level A, wastes cannot be disposed in a near-surface facility; - are between levels A and B, regulators should take decisions on a case-by-case basis; - are below level B, than near-surface disposal conditions are acceptable.

Again, these constraints introduced by the Ukrainian Hygienic Regulations, 2000, are more stringent than those imposed by ICRP, 1998 (1-50 mSv/yr compared to 10-100 mSv/yr).

Due to the fact that the regulatory system on radioactive waste disposal is currently under development in the Ukraine, unacceptable risks associated with the waste dumps within the Exclusion Zone have been defined, within the current project, as those which exceed the international recommended dose constraints.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 10  'HVFULSWLRQRI:DVWH'XPSVZLWKLQWKH&K133([FOXVLRQ=RQH

 ,QGXVWULDO=RQH  'HVFULSWLRQRI6LWH Soils within the ChNPP Industrial Zone were contaminated as a result of the accident at Unit 4. Despite comprehensive decontamination activities that were conducted between 1986 and 1988, the area still has residual contamination.

The contamination is the result of the fallout of fragments of the reactor core and fuel particles. The concentration of reactor core fragments in the soil increases closer to Unit 4. The most contaminated area is that in the immediate proximity to Unit 4, the “Shelter Local Zone”. The Local Zone was decontaminated and bulldozed after the accident, with the radioactive waste being placed into metal containers. The containers (approximately 1700 altogether) with surface dose rates higher than 1Sv/h were buried behind the ‘Pioneer Walls’ erected around the reactor facility and machine room.

Since the accident radionuclide dispersion has taken place due to human activities and natural processes. Human activities within the Industrial Zone impacting on the distribution of contamination include:

- Construction of new buildings and structures involving site levelling and the digging of foundations, maintenance works, renovation and drilling works, construction of subsurface pipelines, etc.; - Decontamination works to reduce the risk of environmental contamination and to prevent radwaste migration; - Decommissioning and final conversion of the site into a ‘green field’ site.

Based on the extent of the decontamination works performed, the investigations of the residual contamination and the assessments of the radioactive waste inventory, the ChNPP Industrial Zone has been divided into three zones (see Figure 3 and Figure 4):

- Shelter Local Zone; - Shelter Industrial Zone; - Units I-III Industrial Zone (located to the east of Unit 4 - “Shelter”).

The overall area of the Industrial Zone, excluding buildings, is approximately 90 Ha. The Shelter Local Zone occupies the most contaminated area, which surrounds Unit 4. It is further subdivided into 6 Sectors as illustrated in Figure 5.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 13  0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV Data relating to the radioactive waste inventory for the ChNPP Industrial Zone were obtained as a result of performing the following activities and subsequent analyses [ISTC, 2000]:

- decontamination work; - geodetic survey of the site; - drilling activities (boreholes, bore pits, etc.); - gamma-logging of man-made layers; - laboratory analysis of core samples.

Investigations were largely concentrated within the Shelter Local Zone, where the depth profile of radioactive contamination was characterised in detail [ISTC, 1998a]. Details relating to the methods of data acquisition and analysis are given in Appendix A.

Cs-137 activity was determined from the measurements of exposure dose rate. Radiometric analysis of core samples from the Shelter Local Zone allowed correlation radios between the activities of different radionuclides in the waste to be determined. These correlation ratios were used to determine the activities of other radionuclides from Cs-137 activity, corresponding to the 26th April 2000.

Exposure dose rate values in boreholes, corresponding to waste of given categories (Ukrainian and IAEA classification systems), were estimated using mathematical modelling (see Appendix A). By comparing the measurements of exposure dose rate with the calculated values, the waste categories were determined.

 :DVWHFKDUDFWHULVWLFV (i) Distribution of radioactive contamination Almost all high-level and long-lived wastes within the ChNPP Industrial Zone are concentrated within the Shelter Local Zone. Within the Shelter Local Zone the soil has been identified as consisting of four layers, which in order of increasing depth are as follows:

- Post-accident man-made layer - Accident related layer - Pre-accident man-made layer - Undisturbed sub-soil layer

The thin accident related layer, of thickness up to 30cm, is characterised by the highest radioactive contamination. The post-accident and pre-accident man-made layers have lower radioactive contamination. The post accident layer has a thickness of up to 10 m. Contamination of the sub-soils is below the free release levels.

No systematic research into the radioactive contamination of the soil in the areas adjacent to ChNPP Units 1, 2 and 3 has been performed. However, some information relating to decontamination work performed in these areas and data on the presence of

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 14 man-made soil layers is available. Based on these data it has been judged that the radionuclide composition and characteristics of waste in the Industrial Zone adjacent to Units 1, 2 and 3 are similar to those of waste within Sectors 1 and 2 of the Shelter Local Zone (Figure 5).

Analysis of the data has shown that radioactive waste is mainly concentrated in the surface man-made layer adjacent to the Unit Shelter boundary and in the area extending from the western boundary of the ChNPP security zone to the liquid radwaste storage and Unit 2 in the east. Reactor core fragments and nuclear fuel can be found in the areas adjacent to the Unit Shelter and Unit 3.

(ii) Physical characteristics of waste Estimates of the waste volumes within the Industrial Zone have been made based on the known cross-sectional area and the estimates of the average thickness of contaminated soil layers. However, due to the limited amount of available data, there is a large uncertainty in these estimates. In 1998 staff of Chernobyl NPP estimated the overall volume of solid radioactive wastes (SRW) in the Industrial Zone, excluding buildings and structures, to be 2,000,000 m3 [OP ChNPP, 1998], corresponding to a thickness of contaminated soil in excess of 2m. However, based on the measurements in the Shelter Local Zone, ISTC experts estimate that the actual waste volume of the whole Industrial Zone is likely to be significantly less than estimated in OP ChNPP [1998]. They estimated the total volume of waste in the Shelter Local Zone to be ~288,000 m3 and for the areas adjacent to Units 1, 2, and 3 to be 100,000 - 150,000 m3.

The radioactive waste within the Industrial Zone largely consists of non-metallic materials such as crushed stone, concrete, sand and gravel. There is some metallic waste including railroad platforms, which were used when constructing the “pioneer” walls to the south of Unit 4, and transformers, etc. Other waste types include protective clothing and equipment, heat insulation, electrical equipment, cables and wood.

(iii) Radiation characteristics of waste The radionuclide composition of the initial dispersed fuel particles was close to that of the Unit 4 irradiated fuel at the time of the accident. As a result the radionuclide composition of the current residual contamination within the Industrial Zone reflects the initial isotopic content corrected by the ingrowth and decay. The inventory is currently dominated by the fission products, with 137Cs, 90Sr and the long-lived transuranic elements 238–241Pu and 241Am being present. The radionuclide composition of the accident-related and post-accident man-made layers within the Shelter Local Zone for 1998 is provided in Table 4 and Table 5.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 15 5DGLRQXFOLGH 6SHFLILFDFWLYLW\UDQJH %TJ

Cs-137 1.0E+03 to 6.0E+05 Sr-90 2.0E+03 to 5.0E+05 Pu-238 2.0E+02 to 4.7E+03 Pu-(239+240) 5.0E+02 to 1.1E+04 Am-241 7.0E+00 to 5.0E+02

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5DGLRQXFOLGH 6SHFLILFDFWLYLW\UDQJH %TJ Cs-137 2.0E-01 to 5.7E+02 Sr-90 2.0E-01 to 7.0E+01 Pu-238 2.0E-03 to 5.0E-01 Pu- (239+240) 3.8E-03 to 1.0E+00 Am-241 3.8E-03 to 1.0E+00 Uranium concentration 2.0E-01 to 8.0E+00 (mg/g)

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The average contamination levels for selected radionuclides for the whole of the Industrial Zone, as reported by Chernobyl NPP, are provided in Table 6 (for 1998). The dose rate varies from 1 to 50 µSv/h at 10cm from the top layer of soil.

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60Co 1.48E+00 134Cs 1.48E+01 137Cs 1.18E+02 154Eu 1.85E+01 241Am 1.11E+01

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 16 (iv) Waste Categorisation

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ISTC estimated that the total volume of radioactive waste in the Shelter Local Zone is approximately 288,000 m3. The classification of radioactive waste within the Unit Shelter Local Zone is shown in Table 7 [ISTC, 1998b] and Table 8 [OP ChNPP, 1999].

5DGZDVWH 6SHFLILF JURXS $PRXQW 5DGZDVWH 6HFWLRQ  DFWLYLW\ ,$($ P  W FRPSRVLWLRQ *%TW FDWHJRU\ I 12900 Sector 1 0.8 Concrete, sand (SL-LILW) (22960) I 9100 3.9 Concrete, sand (SL-LILW) (16200) Sector 2 II 750 230 Concrete, sand (LL-LILW) (1350) I 36500 Concrete, sand, clay, Sector 3 0.45 (SL-LILW) (65000) clay sand I 57000 Concrete, sand, 0.09 (SL-LILW) (101460) rubble II 17650 Concrete, sand, 40 (SL-LILW) (31450) rubble Sector 4 II 250 Concrete, sand, 165 (LL-LILW) (450) rubble III 900 Concrete, sand, 1760 (LL-LILW) (1600) rubble I 119900 Concrete, sand, 0.17 (SL-LILW) (214500) rubble II 3160 Concrete, sand, 38 (SL-LILW) (6150) rubble Sector 5 II 1675 Concrete, sand, 220 (LL-LILW) (3000) rubble III 1700 Concrete, sand, – (LL-LILW) (2500) rubble Concrete, sand, I 17025 1.3 rubble, construction (SL-LILW) (30300) waste Sector 6 Concrete, sand, II 9780 230 rubble, construction (SL-LILW) (17400) waste

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 17 *URXS ZDVWH $PRXQW FDWHJRU\ 5DGZDVWH 5DGZDVWHW\SHVDQGDVVHVVPHQW DFFRUGLQJWR ,' FRPSRVLWLRQ FULWHULD 8NUDLQLDQ  UHJXODWLRQV P W 63$6 63252 1 Nuclear fuel In the soil ≈ 0,6 2 Reactor core Containers with fuel containing III 600 fragments, nuclear materials (see Figure 6) 1100 fuel and others 3 Non-metallic Ground fill (rubble, sand, gravel) materials with a dose rate of more than 1000 III 600 mRem/h (~10 mSv/h) at 10 cm from the surface 4 Building structures Concrete, concrete slabs and blocks with a dose rate of more than 1000 III 900 mRem/h at 10 cm from the surface 5 Metal materials Metal structures with a dose rate of up to 1000 mRem/h at 10 cm from I 1440 the surface 6 Non-metallic Ground-fill with a dose rate of up to I 137000 materials 1000 mRem/h at 10 cm from the II 2000 surface 7 Building structures Concrete, concrete slabs and blocks I 131000 with a dose rate of up to 1000 II 5800 mRem/h at 10 cm from the surface

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 19 Most of the waste in the Shelter Local Zone is solid radwaste of categories I and II (according to SPORO-85 regulations) and short-lived according to the IAEA classification (SL-LILW). It predominantly consists of non-metallic materials such as crushed stone, sand, gravel, concrete, concrete slabs and blocks. There is some metallic waste of categories I and II, namely railroad platforms that were used as a basis when constructing the Pioneer Walls and transformers, etc. A small amount of the waste is classified as long-lived due the significant presence of transuranic elements.

Most of the long-lived waste (LL-LILW), according to the IAEA classification, in the Shelter Local Zone is found within the thin accident-related layer, which has been estimated to contain approximately 15 000 m3 of radioactive waste. In addition there is some long-lived waste that was not removed from the pre-accident soil layer. Nuclear fuel and reactor core fragments that are buried in containers near Sarcophagus (see A in Figure 6) are classified as long-lived waste (Category III according to SPORO-85). This wastes have been investigated within the previous DG Environment-funded project. Rubble, sand, gravel and concrete structures that are in direct contact with nuclear fuel and fuel-containing substances have also been categorised as long-lived waste.

The post-accident and pre-accident man-made layers have a lower level of radioactive contamination. The post-accident man-made layer contains approximately 270 000 m3 of radioactive waste which is largely SL-LILW.

Overall it is estimated that the top layers of soil within the Local Zone contain approximately 283 000 m3 of SL LILW, 5300 m3 of LL LILW and ~1m3 of nuclear fuel.

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No systematic research into the radioactive contamination of the soil in the Industrial Zone outside the Shelter Local Zone has been performed. The quantity of long-lived waste in the Industrial Zone was estimated by analysing data relating to the marginal sectors of the Shelter Local Zone.

The majority of soils within the ChNPP Industrial Zone, outside the Shelter Local Zone, are likely to fall within the short-lived radwaste category. However, some long-lived wastes (LL-LILW) may be located in the soil layer close to the pre- accident surface level (114.0 m above sea level) situated within 50-60 m to the north of the auxiliary systems unit and to the north and to the east of Building “A” of Unit 3. ISTC estimated that the volume of long-lived waste at these sites does not exceed 0.5 – 1.0 % of the total for the post-accident man-made layer, corresponding to approximately 100 to 250 m3 of long-lived waste.

The waste streams which will be generated from the Industrial Zone (excluding buildings), according to estimates made by staff of Chernobyl NPP, in 1998, are shown in Table 9 [OP ChNPP, 1998]. This estimate quoted an overall radwaste volume to be in the order of 2,000,000 m3.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 20  :DVWHVWUHDP :DVWHFDWHJRU\ 9ROXPHP DFFRUGLQJWRWKH 8NUDLQLDQOHJLVODWLRQ Soil I, II 2⋅106 Protective clothing and equipment ? 1,000 Heat insulation ? 1,000 to 10,000 Concrete ? 3000 Metal ? 1,000 to 10,000 Electrical equipment ? 100 to 1,000 Cable ? 100 to 1,000 Other equipment ? 1,000 to 10,000 Wood ? 1,000 to 10,000

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However, based on the measurements in the Shelter Local Zone, ISTC experts believe that the actual waste volume of the whole Industrial Zone is likely to be significantly less than estimated in [OP ChNPP, 1998]. They estimated the total volume of waste for Units 1, 2, and 3 (i.e. excluding Shelter Local Zone) to be between 100 000 and 150 000 m3 [ISTC, 2000]. The latter estimate corresponds to the overall radioactive waste volume in the Industrial Zone of around 400 000 m3.

 $QDO\VLVRIUHOLDELOLW\RIGDWD Here, as elsewhere, the Chernobyl radionuclide composition is based on the inventory of fuel from Unit 4. While this is relatively accurate for the majority of wastes, that are contaminated by fuel particles, the radionuclide content of activated reactor components is significantly different.

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The Shelter Local Zone represents the most studied area within the Industrial Zone. Analysis of the data relating to radioactive waste volume and composition within this zone identified the following inadequacies:

1. The studies that have been performed within the Local Zone had varying aims and no systematic character. This prevents an adequate verification of the data. 2. There is a lack of authentic documentation relating to the scope of the decontamination work performed and to the characteristics of the man-made radioactive waste layer. Of particular concern are data relating to the radioactive waste situated behind the “Pioneer” walls, which is of higher activity and poses a significant hazard to the environment and to personnel. This will be especially important during the “Shelter-2” construction. 3. There is a network of monitoring boreholes within the Local Zone. Analysis of the measured data from these boreholes formed the basis of waste classification activities [ISTC 1998a & 1998b]. However,

- the network does not cover all the Local Zone territory - the wells were drilled for various purposes and by various organisations NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 21 - the wells are not uniform in size or construction and many of them are being adequate to perform the necessary surveys - measures to safeguard against contamination of the wells during construction were not used - the boreholes are located irregularly and in insufficient numbers to make an accurate estimate of radwaste inventory and volumes.

4. Of the boreholes drilled, to date, only some have undergone gamma logging and only core samples from some have been analysed. 5. Various expert assessments of the quantity of radwaste in the Local Zone have been made based on estimates of the thickness of contaminated soil. The data were not obtained on a systematic basis and the large variation in the estimates suggests that there are inadequacies in the source experimental data. 6. Gamma spectrometry and radiometry were used as the main methods of measurement. However, taking into account the waste characteristics, the methods used were insufficient to accurately determine the radionuclide composition and the distribution of volumetric and surface contamination. In order to determine the content of 238-241Pu, 241Am and 90Sr in the waste, analysis of the volumetric and surface contamination due to these elements is required. Such analysis is labour intensive and requires additional equipment. 7. No systematic measurements of the contamination of the Industrial Zone surface layer have been made which are necessary to complement the borehole data. 8. A relationship between 137Cs specific activity and exposure dose rate has been determined using a Monte-Carlo method, and this relationship has been used as the basis for waste classification [ISTC, 1998b]. However, values of 137Cs specific activity, obtained from the radiochemical analysis of core samples with similar values of exposure dose rate, were found to differ in some cases by up to an order of magnitude [ISTC, 1998a]. 9. The discrepancies concerning the correlation dependence between the gamma- logging and the radionuclide composition of core samples, demonstrate poor accuracy of the measurements. 10. Insufficient experimental data, inaccuracies in measurements and the lack of any systematic process to characterise the radioactive waste give rise to significant uncertainties in the categorisation of radioactive waste.

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The analysis of the data relating to radioactive waste volume and composition outside the Shelter Local Zone identified the following issues:

1. No systematic research of soil contamination in the ,QGXVWULDO=RQH outside of the Shelter Local Zone has been performed. 2. Gamma-logging of boreholes outside the Shelter Local Zone has not been performed. The sources of increases in equivalent dose rates observed for some boreholes have not been adequately described. 3. No research to assess the radioactive waste inventory outside the Shelter Local Zone has been performed. 4. The estimates relating to the ,QGXVWULDO=RQH outside the Shelter Local Zone are based on expert judgement and derived from the data obtained within the Local Zone. These estimates vary significantly. For example estimates for the volume

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 22 5 6 3 of wastes in the ,QGXVWULDO =RQH range from 10 to 2×10 m , indicating high uncertainty levels. 5. In order to assess the waste inventory outside the Local Zone adequetly, additional research including core sampling, gamma-logging and geodetic surveys is required.

 ,GHQWLILFDWLRQRIIXUWKHUDFWLYLWLHVUHTXLUHGWRLPSURYHGDWDTXDOLW\ Reliable data on the quantity, type, radionuclide composition, and waste activity within the Industrial Zone are required for the planning of the activities associated with the removal and disposal of radioactive waste, which are to be carried out within the framework of the transformation of the Unit Shelter and closure of the Chernobyl NPP in accordance with the requirements of the Ukrainian modern standards.

To date, detailed surveys of the distribution of contamination and assessments of the total activity of radioactive waste have been restricted to the Local Zone. However, even for the Local Zone, these surveys do not provide reliable data for an assessment of the radiological situation to be performed. In relation to the Shelter Local Zone, the data to date consist largely of the results of surveys of core samples and borehole gamma-logging. Critical analysis of the data identified poor accuracy of measurements, insufficient experimental data and a lack of any systematic waste characterisation.

Outside the Local Zone, there is even less information. Additional surveys are required to provide more accurate data relating to the quantity and composition of the radioactive waste within the Industrial Zone. It is judged that some of the current estimates of the waste inventory are based on conservative assumptions. It is thus expected that improvements in the data accuracy will result in lower waste quantities. The recommended sequence of additional activities to be performed within the Industrial Zone is indicated in Figure 7.

The recommended initial task of any further work involves an analysis of the history of operations at the Chernobyl NPP, in particular those leading to the contamination of the Industrial Zone, and including the accident in 1986.

Existing data from core surveys, gamma-logging, and other investigations into the radiological situation should be analysed to identify additional surveys that are required. In particular it necessary to determine

- the locations where further measurements are required - the type of necessary measurements. - planning of the measurement programme

It is important to select a survey method or a set of survey methods. The appropriate survey methods will depend on the practical implementation of the specific methods, available data, character of the surveyed territory, availability and sufficiency of the sampling sites (boreholes), and the forecasted waste characteristics. Under the current conditions, the following methods can be implemented:

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 23 - Site characterisation using the existing wells (gamma-ray logging, radionuclide measurements, core survey, etc.); - Geophysical survey (application of georadar, magnetometers, etc.); - Survey involving drilling of new boreholes; - Site characterisation (gamma-logging and analysis of core samples at shallow depth, without drilling new boreholes.

The appropriate method of measurement depends on the chosen survey method and the waste characteristics. The data obtained should be analysed and input into a database. If at this stage the data is still judged to be insufficient or not of the required quality, additional surveys will have to be identified.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 24 Historical analysis of the accident which resulted in contamination of the Industrial Zone Core samples radionuclide composition

Results of gamma-ray logging Radiation situation at the surveyed Analysis and processing of the existing territories (maximum dose rate, data surface contamination)

Selection of locations to be surveyed Assessment of survey scope

Selection of objectives Planning of work

Sampling Selection of survey method Drilling of new boreholes

Geophysical methods

Survey of existing boreholes

Gamma-spectrometry Data obtaining and processing Gamma logging

Radiometric survey Entry of obtained data into a database

Radiochemical survey Analysis of the results

NO Analysis of data quality and reliability

YES

Development of technical proposals on waste removal from surveyed territories and waste management technologies )LJXUH7DVNVUHTXLUHGWRFDWHJRULVHWKHZDVWHDWWKH,QGXVWULDO=RQH

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 25  3=523RGOHVQ\  'HVFULSWLRQRI6LWH PZRO Podlesny was commissioned in December 1986. It was constructed on the site of the former farm Podlesny, approximately 2.5 km to the East of the Pripyat town and 1.5 km to the North of the Chernobyl NPP (Figure 8 and Figure 9). The distance to the Pripyat inlet is about 550 m and the River Pripyat is approximately 1.2 km to the north of the PZRO. The filtration fields of the sewage treatment facility adjoin the PZRO site from the south. The area occupied by the site is 60,000 m2.

The PZRO is an above-surface facility. The ground surface at the Podlesny site is approximately at a height of 115.5 m above the level of the Baltic Sea and the hydrogeological conditions at the site are generally favourable. The groundwater table is 5.5 – 7 m below the surface, with the unsaturated zone being composed of sand and clay. Groundwater movement is towards the Pripyat river.

Podlesny was designed for the disposal of radioactive waste with gamma dose rates of up to 50R/h (~500 mSv/h), the majority of which originated from the Industrial Zone (‘Promploshadka’). The construction of the PZRO consisted of two stages. During the first stage two concrete compartments, A-1 and B-1, were constructed. A-1 was designed for the disposal of tanks loaded with wastes and B-1 was designed for the disposal of loose materials. During the second stage an extra six compartments were constructed (Figure 10).

The compartments consist of concrete walls, formed from pre-cast concrete and concrete blocks, placed on a common 1.5m thick concrete slab. The cross-sectional dimensions of the base are 50 m x 30 m and the walls are 8-9 m high. The A-1 compartment walls are 1.12 m thick and the B-1 compartment walls are 2.4 m thick. A 4-5m high dike has been constructed around the compartment walls. Figure 11 illustrates the schematic of the B-1 compartment. A photograph of the PZRO is shown in Figure 12.

In 1988 a structural assessment of the facility revealed three constructional defects: soil settlement, fractures in the basement and fractures in the compartment walls. As a result of this assessment and taking into account the Sanitary Rules for Radioactive Waste Management-85 (SPORO-85), radioactive waste disposal at the site was suspended in November 1988. Improvement works for the A-1 and B-1 compartments were performed in 1990. 2300 - 2400 m3 of concrete was poured into each of the compartments and 650 m3 of a mixture of sand and crushed stone was placed on top of the grouted radioactive waste.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 31  0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV Between 1986 and 1990, 14 monitoring boreholes were drilled within the Podlesny site in order to monitor groundwater [Antropov et al, 2000b] (see Figure 9).

In November 1988, research into the waste inventory was carried out by the All- Russian Research Institute for NPP Operation (VNIIAES). This 1988 inventory was presented in the documents: “Radioactive Waste Disposal Station Sanitary Passport” [SSE Complex, 1990a] and “Results of radioactive waste storage and disposal areas inventory according to 01/01/90 status” [SSE Complex, 1990b]. The data, without adjustment for radioactive decay, were used by the State Special Enterprise “Complex” for compiling the 1990 Exclusion Zone Waste Inventory Register. The methods used to obtain the data are unknown.

A radiation survey of PZRO Podlesny was carried out in October 1995 by the Dosimetric Monitoring Management Radiation Safety Shop. In 1995, 14 additional boreholes were drilled during the preparations for improvements to compartments A-1 and B-1 [Antropov et al, 2000b].

Revised assessments regarding the waste inventory of Podlesny have been performed by the State Special Enterprise “Complex” and STC “KORO” with reference to the All-Russian Research and Design Institute for Power Technology reports [VNIPIET, 1991a & 1991b] and the Kyiv Institute “Energoproekt” report [Energoproekt, 1995]. The methods of data analysis have not been described.

 :DVWHFKDUDFWHULVWLFV (i) Physical characteristics Two compartments at the PZRO, A-1 and B-1, are half full with radioactive wastes; the remaining six compartments are empty. The source of the radioactive waste is largely from the decontamination of Units 3 and 4, consisting of graphite, metal, reactor core construction materials, and construction wastes [SSE Complex, 1990a]. Some of the waste stored within the A-1 compartment is contained within metal containers.

Data on the volume and physical properties of the waste disposed at Podlesny, presented in the 1990 Inventory Report, are shown in Table 10.

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Parameter Value Waste Volume 11 000 m3 Waste Mass 22 000 tones Physical composition Graphite, reactor core constructional materials, constructional wastes

However, according to the data presented in the Energoproekt report [Energoproekt, 1995], only 2650 m3 of solid radioactive waste were loaded into compartment A-1 and 1310 m3 of high-level wastes were loaded into compartment B-1. In 1990 the wastes were grouted with 2300 m3 and 2500 m3 of concrete being added to the wastes in A-1 and B-1 respectively. In addition 650 m3 of sand/gravel was used to cover each compartment.

From ISTC data (Table 8), the waste within the Industrial Zone consists of largely sand/soil and concrete in roughly equal quantities. On the basis of this data the physical composition of the waste in Podlesny has been estimated as 50% sand/soil and 50% concrete.

(ii) Radiation characteristics The 1995 survey identified the most contaminated area within the PZRO as being located between the A-1 and B-1 compartments, with exposure dose rates up to 200 – 700 µSv/h. High dose rates of 120-140 µSv/h were also measured directly above the compartments. Other areas within the PZRO largely had exposure dose rates within the limits of 2 – 5 µSv/h [Antropov et al, 2000b].

According to the data presented in the 1990 Waste Inventory Register, the activity of the waste in Podlesny in 1988 was 3 x 1015 Bq (7 x 104 Ci).

According to the Energoproekt report [Energoproekt, 1995], in 1987 the total activity of waste at Podlesny was 7 x 107 Ci, and for 2000 the total activity was estimated to be 2 x 107 Ci. This value of 2 x 107 Ci for the radwaste activity (for the year 2000) was used in “PZRO Podlesny Enterprise Standard” [SSE Complex, 2000], which has been recently developed by STC KORO and approved by the State Special Enterprise “Complex”. However, as detailed further (see Section 3.2.4) it has been shown that this estimate contradicts the data on the initial fuel inventory contained in Unit 4 at the time of the accident.

The radioactive wastes concentrated in the PZRO have a characteristic radionuclide composition close to that of the irradiated nuclear fuel of ChNPP Unit 4 at the time of the accident. Table 11 shows the radionuclide composition of waste at Podlesny in 1987 according to the Energoproekt report [Energoproekt, 1995].

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Radionuclide Type of Half-life Specific Activity, Activity, Emission Ci/m3 Ci 90Sr β 29.12 years 1.04x103 4.13x106 95Zr β 63.98 days 5.38 2.13x104 95Nb β 35.15 days 5.38 2.13x104 99Tc β 2.13x105 years 2.04 8.06x103 106Ru β 368.2 days 2.07x103 8.2x106 106Rh β 29.9 seconds 2.07x103 8.2x106 125Sb β 2.77 years 7.42x101 2.94x105 134Cs β 2.062 years 1.02x103 4.03x106 137Cs β 30 years 1.37x103 5.41x106 137mBa β 28.7 hours 1.37x103 5.41x106 144Ce β 284.3 days 2.36x103 9.35x106 144Pr β 17.28 minutes 2.36x103 9.35x106 147Pm β 2.6234 years 1.4x103 5.55x106 151Sm β 90 years 2.12 8.4x103 154Eu β 8.8 years 9.87x101 3.91x105 155Eu β 4.86 years 6.11x101 2.42x105 243Am α 7380 years 1.27x10-1 5.04x102 239Pu α 24065 years 3.56 1.41x104 244Cm α 18.11 years 4.24 1.68x104 240Pu α 6537 years 8.36 3.31x104 238Pu α 87.74 years 1.39x101 5.42x104 238U α 4.468x109 years 6.67x10-3 2.64x101 242Pu α 3.763x105 years 2.28x10-2 9.03x101 241Am α 432.2 years 1.91 7.56x103 241Pu β 14.4 years 1.28x103 5.07x106 Total Activity 1.66x104 7.00 x 107

(iii) Waste classification The waste within the PZRO is classified as HLW according to the Ukrainian regulations and long-lived according to the IAEA classification system.

In addition the 4800 m3 of concrete grout added to modules A-1 and B-1 has been classified as short-lived waste (IAEA classification system).

 $QDO\VLVRIUHOLDELOLW\RIGDWD (i) Radioactive waste volume Reliable data on the volume of radioactive waste disposed at Podlesny are available. The assessments of waste volume presented in the Energoproekt report (of 2650 m3 in

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 34 A-1 and 1310 m3 of waste in B-1 prior to grouting) are accepted. In addition however, 2300 m3 and 2500 m3 of concrete grout were placed on top of the waste in A-1 and B- 1 respectively. There is no data relating to the proportion of this concrete which is contaminated or the level of contamination. Currently all 4800 m3 of the concrete grout have been classified as short-lived waste, however, the contamination within the concrete will vary with that at the surface possibly being contaminated to levels below the free release threshold.

(ii) Radioactive waste activity There is a significant discrepancy between the values for the total activity of waste at Podlesny presented in the 1990 Exclusion Zone Waste Inventory Register and in the 1995 Energoproekt Report. In both cases the assessment methods used are unknown.

The value of 2x107 Ci for the total activity in 2000, as determined by the Kiev Institute “Energoproekt”, has been demonstrated to be erroneous as detailed below.

According to the Energoproekt data, the total activity of Plutonium-239 has been estimated as 14100 Ci (Table 11). According to the ISTC “Shelter” data the specific activity of Plutonium-239 in the ChNPP Unit 4 fuel is 5 MBq/g [ISTC, 1996]. Using these data the following estimated value for the fuel mass (0) in radioactive waste at Podlesny is obtained:

10 6 0= (14100 Ci * 3.7 10 Bq/Ci) / (5 10 Bq/g) = 104 300 kg ≈ 104 tonnes.

It is known that at the time of the accident the total weight of fuel for ChNPP Unit 4 was 190.3 tonnes. Based on thermal measurements, the Kurchatov Institute of Nuclear Energy estimated (for 1986) that not less than 87% of the fuel was concentrated inside the Unit Shelter, not more than 0.3% of fuel was concentrated at the ChNPP Industrial Zone, and the fallout of fuel particles outside the Industrial Zone was up to 4% [Belyaev et al, 1990]. According to the later estimates, made by Borovoy et al, 1995, 172.9 ± 28 tonnes of fuel are concentrated inside the Unit Shelter, and 6.7 ± 1 tonnes of fuel particles are found outside of the ChNPP Industrial Zone, leaving a remainder of 10.7 tonnes. Thus, the statement that more than a half of total Unit 4 fuel inventory is placed at Podlesny is in contradiction with the data on the initial quantity of fuel and the likely proportion of this fuel outside the Unit Shelter and the Industrial Zone.

Data relating to the characteristics of radioactive waste located at PZRO Kompleksny suggest that the lower activity value assessed for Podlesny (7x104 Ci in the 1990 Inventory Register) is more realistic. PZROs Podlesny and Kompleksny accepted waste over the same period (from the end of 1986 to the end of 1988), and according to the descriptions available they accepted similar types of waste, which in both cases originated from the decontamination of ChNPP Units 3 and 4. The layout of the disposal sites produced by the civil defence troops in 1988 gives the total activity of both disposal sites as being 5 x 105 “standard units of activity ” (see Appendix B; the use of the expression “standard units” is determined by the fact that the data were secret at that time). This again points at the lower activity value assessed for Podlesny as being appropriate.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 35 According to the assessments performed under the current project, the average specific activity of wastes at PZRO Kompleksny is 106 Bq/kg (for year 2000). The Kiev Institute “Energoproekt” report data estimates the average specific activity of radioactive waste at Podlesny as 1011 Bq/kg (for the year 2000), i.e. 100,000 times higher than the assessments for Kompleksny. It is possible that more highly radioactive wastes are concentrated at Podlesny compared to Kompleksny, however a discrepancy of 100,000 times cannot be explained.

In conclusion, the inventory register assessment (1990) for the total activity at Podlesny of 70,000 Ci (for the year 1988) is considered to be more realistic, and the assessments of total activity and specific activity in the 1995 Energoproekt report erroneous.

Comparison of the 1990 “Exclusion Zone radioactive waste inventory results” with the data obtained from the later surveys of the radioactive waste storage facilities performed by STC “KORO” reveals that, in general, the 1990 inventory register data deviate from the actual data by an order of magnitude and are mostly overestimates. The discrepancy between the 1990 inventory register data and the actual data may be explained by the methods used to assess activity. From the comparison of the actual data with the 1990 inventory register data, for those storage facilities surveyed, it may be deduced that similarly for Podlesny the inventory register data overestimate the actual activity by an order of magnitude. A more accurate assessment of the reliability of the Inventory data cannot be made since the methods used to obtain the data are unknown.

(iii) Assessment of waste activity adjusted for radioactive decay The value for total activity presented in the 1990 Inventory Register corresponds to the total activity of Podlesny at the end of 1988. Hence the total activity of Podlesny in 1988 is accepted to be 7x104 Ci, with the waste volume being accepted to be ~4000 m3.

The total activity in 1988, adjusted for decay is provided in Table 12. The radionuclide composition of the waste has been estimated using the ISTC “Shelter” data concerning the radionuclide composition of fuel particles at the ChNPP Industrial Zone.

Table 13 gives a summary of the information relating to the radioactive waste disposed at Podlesny. The assessment of the average specific activity of transuranic (TRU) radionuclides within the waste, after adjustment for radioactive decay, gives a value of 1800 Bq/kg. Thus the radioactive waste at Podlesny corresponds to the long- lived waste category according to the IAEA classification.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 36 Radio- Type of Contribu- Activity Specific Activity Specific nuclide emission tion to (31.12.88) activity (01.01.00), activity activity, % Bq (31.12.88), Bq (01.01.00), (31.12.88) Bq/g Bq/g

90Sr beta 17,71 4,59E+14 5,73E+04 3,51E+14 4,39E+04 134Cs beta, gamma 5,69 1,47E+14 1,84E+04 3,63E+12 4,53E+02 137Cs beta, gamma 20,73 5,37E+14 6,71E+04 4,17E+14 5,21E+04 144Ce beta, gamma 29,01 7,51E+14 9,39E+04 4,19E+10 5,23E+00 154Eu beta, gamma 0,92 2,38E+13 2,97E+03 9,99E+12 1,25E+03 238Pu alpha 0,10 2,71E+12 3,39E+02 2,49E+12 3,11E+02 239Pu alpha 0,08 2,04E+12 2,55E+02 2,04E+12 2,55E+02 240Pu alpha 0,13 3,34E+12 4,18E+02 3,34E+12 4,17E+02 241Pu beta 13,29 3,44E+14 4,30E+04 2,03E+14 2,53E+04 241Am alpha, gamma 0,05 1,37E+12 1,71E+02 6,01E+12 7,51E+02 244Cm alpha 0,03 8,10E+11 1,01E+02 5,31E+11 6,64E+01 Total 2,27E+15 2,84E+05 9,99E+14 1,25E+05

Total alpha 1,03E+13 1,28E+03 1,44E+13 1,80E+03

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Here, as elsewhere in the Chernobyl, radionuclide composition is based on the inventory of fuel from Unit-4. While this is relatively accurate for the majority of wastes, contaminated by fuel particles, radionuclide content of activated reactor components should be significantly different. This is especially relevant to PZRO Podlesny, which contains a Unit 4 construction debris, graphite and other similar materials.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 37 Parameter Value Waste volume in A-1 compartment (storage in 2650 metal containers), m3 Waste volume in B-1 compartment (in bulk 1310 storage), m3 Total waste volume, m3 3960 Total mass, tonnes ~8000 Physical composition of waste (estimated) Graphite, ChNPP Unit 4 constructions debris, ChNPP Industrial Zone construction wastes 7RWDOZDVWHDFWLYLW\  Caesium-137, Bq 4.2x1014 (Ci) (11350) Sum of caesium-137, Strontium-90, Plutonium- 1.0x1015 241, and TRU, Bq (Ci) (27000) TRU (Plutonium-238,239,240, Americium-241), 1.4x1013 Bq (380) (Ci) $YHUDJHVSHFLILFDFWLYLW\RIZDVWH  Caesium-137, Bq/g 52000 Sum of caesium-137, Strontium-90, Plutonium- 125000 241, and TRU, Bq/g TRU, Bq/g 1800

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 ,GHQWLILFDWLRQRIIXUWKHUDFWLYLWLHVWRLPSURYHGDWDTXDOLW\ In order to obtain a more certain value for the waste inventory of Podlesny a full survey of the storage facility is required.

It is possible, that data relating to the radioactive waste characteristics could be obtained by the thorough analysis of archive materials relating to Podlesny (for example, data on the measured actual values of received radioactive waste exposure dose rates). However, the fact that such data have not been collated and are not systematic, renders such an analysis extremely difficult.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 38  3=52.RPSOHNVQ\  'HVFULSWLRQRI6LWH PZRO Kompleksny is situated 1.5 km to the south-east of the ChNPP main building, within the ChNPP Stage III site (i.e. the site where Units 5 and 6 of the ChNPP were to be constructed until the 1986 accident occurred) (Figure 13).

The radioactive waste storage facility is referred to in different documents under different names. The official title of the facility is “ChNPP Stage III”, according to the OLFHQFHIRU3=5 DQG39/52RSHUDWLRQZKLFKZDVJUDQWHGWR66(³&RPSOH[´E\ the Ministry of Environmental Safety [STC KORO, 1996b]. However, the facility will be referred to as PZRO Kompleksny throughout this report, which is its commonly accepted name.

According to data provided by SSE “Complex”, the PZRO was commissioned in October 1986, for the disposal of HLW (Ukrainian legislation) from the Industrial Zone of ChNPP (Promploshadka). The PZRO was filled in the period from October 1986 to l December 1988.

The PZRO consists of seven reinforced concrete compartments, which are 6m wide, 5m deep and vary in length from 90 to 140 m. The base of the storage facility is made of monolithic reinforced concrete. Figure 14 shows the layout of the facility, based on a photograph taken prior to its closure. The voids at the ends of the compartments have also been used for the storage of radioactive waste [Ledenev, 2000]. Figure 15 and Figure 16 show the layout of the storage facility and the cross section of the storage compartments in more detail.

During the closure of the storage facility, the compartments were filled up with sand. The compartments were then covered with a layer of soil of thickness 1.0-1.5 m, followed by a layer of compacted clay about 1.0 m thick. Above the clay there is a further 15-20 cm thick layer of soil into which perennial grass has been planted (see Figure 16 and Figure 17).

The storage facility is fenced with barbed wire. A drainage ditch with four water- collecting wells is situated around the perimeter of the storage facility. However, the collection wells do not have a waterproof lining and are partially filled with sand. Any rainwater that collects in the wells is not pumped out. In addition there is a network of groundwater monitoring wells installed around the perimeter of the PZRO (see Figure 15).

Full-scale surveys conducted by STC “KORO” in 1996 revealed the presence of numerous depressions on the surface of the PZRO (Figure 18). These were formed as a result of subsidence and resulted in containers of waste being exposed at the surface. Following the surveys, SSE “Complex” filled up the depressions with sand. However, this was not fully effective since the subsidence can currently be observed in the surface layer of the storage facility.

The soil at the site consists of alluvial sands and loamy sands. The ground surface is at a height of about 115m (above the Baltic sea level). The depth of the groundwater

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 39 table is about 5m. Groundwater flows towards the ChNPP Cooling Pond, which is located at a distance of 150 m.

The survey conducted in 1996 by STC “KORO” revealed that the PZRO is flooded, with the groundwater level varying between 0.5 and 0.7 m above the bottom of the waste, depending on the season. According to the data provided by IGS, several building drainage holes situated at the Kompleksny site were in service during the period of operation of the storage facility (1986-88), however subsequently the drainage holes have been blocked. As a result the level of the groundwater table has risen and this has contributed to the flooding of the PZRO.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 45  0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV STC KORO surveyed PZRO Kompleksny in 1996 [STC KORO, 1996b].

In order to determine details relating to the design of the storage facility, the following methods were applied:

- exploration-drilling; - visual inspection of the storage facility (Due to subsidence the top of the eastern wall of the storage facility is exposed); - gamma-logging of drilled boreholes.

A radiation survey of the PZRO was performed by STC “KORO” in 1996, in order to determine the waste inventory. This included gamma surveying in the surrounding territory in order to determine the activity of wastes that had been disposed in the regions at the ends of the storage compartments.

When surveying the alignment of the eastern compartment of the PZRO, some boreholes were drilled into the waste compartment, spaced at 10 m intervals. Gamma logging of these boreholes was performed. In addition, depressions as a result of subsidence also exposed some waste containers allowing dose rate measurements to be performed for several tens of containers. A total of 440 dose rate measurements were made inside the storage facility to depths of the disposed waste. In addition, 326 dose rate measurements were made in subsidence holes (as reported by STC KORO).

Based on the experimental data obtained during the 1996 survey, STC KORO performed an analysis of the waste characteristics [STC KORO, 1996b]. A number of errors have been identified in these calculations and a more accurate analysis of the experimental data, obtained during the 1996 survey, has been performed within the framework of the current project. The specific activity of caesium-137 was determined from the measurements of exposure dose-rate (see Appendix A). Correlation ratios for the ChNPP site waste, determined by experts from ISTC “Shelter”, were used to assess the activity of the other main dose-contributing radionuclides and transuranic elements.

 :DVWHFKDUDFWHULVWLFV (i) Physical characteristics According to estimations made by STC “KORO”, there are about 18,000 metal containers containing radioactive waste within the compartments. Each container has a volume of 1m3 and walls of thickness ranging from 1 to 1.5mm. The containers were placed into the storage facility in 1987 and are assumed to contain debris from the ChNPP Unit 4, topsoil and other wastes from the ChNPP site. In addition the space at the ends of the compartments has been filled with unpackaged waste.

Taking into account the fact that the containers were loaded into the compartments in bulk, as confirmed by an aerial photograph (Figure 14) prior to capping of the facility and by visual surveys of subsidence holes, the fraction of the total volume occupied by waste containers was estimated to be 0.7. Several open containers were easily

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 46 observable in some of the subsidence holes and as a result it was possible to determine the extent to which the waste containers were filled with waste. Since all containers were two-thirds full, the fraction of the total volume of the containers occupied by waste was assumed to be 0.7 [Ledenev, 2000].

The amount of radioactive waste in the containers has been estimated to be approximately 12,400 m3. Using a waste density of 1.6 t/m3, the mass of waste within the containers was estimated to be approximately 20,000 tonnes. In addition the volume of loose waste contained in the regions at the ends of the compartments was estimated to be 13,800 m3, assuming a waste depth of 3 m and a cross-sectional area of 4600 m2. The mass of loose waste was estimated as 22,000 tonnes. Hence, the total volume of radioactive waste disposed in PZRO Kompleksny is estimated at 26,200 m3, with a mass of 42,000 tonnes.

The physical characteristics of the waste disposed at Kompleksny in 1996, based on the results of the STC KORO survey, are summarised in Table 14. Based on ISTC data (Table 8), the waste in the Industrial Zone consists of largely soil/sand and concrete in roughly equal proportions. Based on this data the waste in Kompleksny has been estimated as consisting of 50% soil/sand and 50% concrete/brick.

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Parameter Value The volume of radwaste in metal containers, m3 12,400 The volume of radwaste in bulk, m3 13,800 Total volume of waste, m3 26,200 Total mass of waste, tonnes 42,000 Physical composition of waste Soil, ChNPP Unit 4 debris, construction waste and ChNPP site wastes.

(ii) Radiation characteristics The 1996 radiation survey, performed by STC KORO [STC KORO, 1996b], gave gamma dose rate measurements of up to 34µSv/h on the surface of the facility. The magnitude of beta-contamination at the surface was also measured to vary from 50 to 5800 beta-decays/(cm2 min). Gamma-logging of boreholes drilled into the waste compartments gave gamma dose rates of 1.0 to 15 mR/h (~ 10 to 150 µSv/h) at the top of the waste containers. Gamma dose rates at the walls of the waste containers exposed as a result of subsidence varied between 1.0 and 47 mR/h (~ 10 to 500 µSv/h).

From the measurements of average exposure dose rate at the surface of the waste containers the average specific activity of caesium-137 in the waste in 1996 was estimated to be 830 Bq/g [Levchuk, 2000]. Assuming a total mass of waste of 42,000 tonnes, the total activity of caesium-137 in 1996 was estimated as 35 TBq (946 Ci).

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 47 From the measurements of maximum dose rates at the walls of containers inside the storage facility, the maximum specific activity of caesium-137 in PZRO Kompleksny in 1996 was estimated to be 1400 Bq/g (see Appendix A for details of methodology).

The results of the assessment of the characteristics of the waste disposed in PZRO Kompleksny for the year 2000 (taking into account radioactive decay since the survey in 1996) are given in Table 15. The total activity, obtained as a result of the summation of the activities of the main dose-contributing radionuclides in the PZRO, was estimated to be about 74TBq (2000 Ci, for the year 2000). It should be noted that this value is an order of magnitude less than the value indicated in the inventory provided by SSE “Complex ” for the 1st December 1998 of 12 727 Ci.

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Parameter Value 7RWDODFWLYLW\RIZDVWH Caesium-137, Bq 3.2x1013 (Ci) (863) Sum of caesium-137, strontium-90, plutonium-241, and 7.5x1013 TRU , Bq (2032) (Ci) TRU (plutonium-238,239,240, americium-241), Bq 1.1x1012 (Ci) (30) $YHUDJHVSHFLILFDFWLYLW\RIZDVWH Caesium-137, Bq/g 757 Sum of caesium-137, strontium-90, plutonium-241, and 1780 TRU, Bq/g TRU, Bq/g 26.6 0D[LPXPVSHFLILFDFWLYLW\RIZDVWH Caesium-137, Bq/g 1280 Sum of caesium-137, strontium-90, plutonium-241, and 3000 TRU, Bq/g TRU, Bq/g 45

(iii) Waste classification In accordance with SPORO-85, most of the waste disposed in PZRO Kompleksny, as of 1996, is classified as group I (low-level) waste. The proportion of waste classified as group II (SPORO-85), with dose rates >30 mR/hour, according to estimations made by STC “KORO”, is less than 30%.

The assessments performed as part of the current project, based on the 1996 STC KORO Survey data, found that the maximum content of alpha-emitting transuranic elements in the waste at Kompleksny does not exceed 45 Bq/g (Table 15). Consequently, in accordance with the IAEA classification, the waste corresponds to short-lived waste. Earlier reports suggested that KORO’s own estimates were quite different, with the activity of 239Pu and 240Pu being quoted as 290 GBq (i.e. smaller than the latest estimate) and the volume of long-lived waste as 524m3 (compared to 0).

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 48 It should be noted that the assessments made using the 1996 STC KORO data are based on a relatively small number of the available measurements. Since no measurements have been undertaken in the majority of containers or unpackaged waste, it is possible that long-lived waste is present within PZRO Kompleksny.

 $QDO\VLVRIUHOLDELOLW\RIGDWD The maximum TRU concentration in Table 15 is only 1.5 times the average, which is significantly less than was found for some other locations, such as Buryakovka or Exclusion Zone, where maximum and average α-activities vary by orders of magnitude. It can be inferred that STC KORO have measured wastes, which were relatively homogenous in composition. It is feasible that some of the wastes, stored at lower levels and locations outside the area studied by STC KORO contain long-lived wastes. Altogether activity was measured in only several tens of containers of the total number of 18,000.

Here, as elsewhere in Chernobyl, radionuclide composition is based on the inventory of fuel from Unit-4. While this is relatively accurate for the majority of wastes, contaminated by fuel particles, radionuclide content of activated reactor components should be significantly different. However, from the available information, it is judged that there relatively few such components within PZRO Kompleksny.

A more detailed survey of PZRO Kompleksny is required to decrease the level of data uncertainty.

 3=52%XU\DNRYND  'HVFULSWLRQRI6LWH PZRO Buryakovka is located 12 km from ChNPP (Figure 1). It was commissioned in February 1987 and is still operating as a waste disposal facility.

The Buryakovka site is 1200 m by 700 m. It contains 30 storage trenches, each of cross-sectional dimensions 140 m by 60 m and of 4m depth (Figure 19). A 1m thick layer of compacted clay lines the bottom of the trenches. The trenches are capped with a 0.6m thick soil layer, above which there is a 0.5m thick clay layer and a 1m thick soil surface layer (Figure 20).

The hydrogeological conditions at the Buryakovka site are generally favourable. The ground level is at approximately 140 m above the level of the Baltic Sea and the groundwater table is 14-18 m below the surface. The soils at the site consist of Fluvioglacial sands and loamy sands. A network of observation boreholes has been constructed around the perimeter of the trenches in order to monitor groundwater [Antropov et al, 2000a] (See Figure 19).

Buryakovka was designed for the disposal of low and intermediate-level solid radioactive wastes. The current waste acceptance criteria at Buryakovka are as follows:

- Solid radioactive waste of Chernobyl origin;

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 49 - Short-lived radioactive waste of groups 1 and 2 (From 0.3 µSv/h to 10 mSv/h); - 4XDQWLW\RI HPLWWLQJUDGLRQXFOLGHVXSWRRIWKHWRWDODFWLYLW\

However, until 01.01.1990 Buryakovka accepted solid radioactive waste with exposure dose rates up to 5 R/h (~ 44mSv/h using 1R ~ 8.8x10-3 Sv) [Antropov et al, 2000a].

On average, approximately 30,000-40,000 m3 of radioactive waste is disposed of at Buryakovka per year. The source of the waste is largely the decontamination activities being performed within the Exclusion Zone, but also waste generated from operations at ChNPP, Unit Shelter and other enterprises within the Exclusion Zone.

The wastes are loaded into the trenches in bulk (Figure 21), and then compacted using heavy machinery. Each trench contains about 20,000-35,000 m3 of waste at source, which is then compacted to typically about 3000 m3. Currently 24 of the trenches have been filled, of which 17 have been fully covered. Two trenches are 90% full, with the remaining 4 trenches being empty. The stages of capping a trench with layers of sand, clay and grass are illustrated in Figure 22.

In addition to the storage trenches, there is a temporary open-air storage site at Buryakovka. Metal wastes, consisting of contaminated machinery, are temporally stored here (Figure 19).

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 52 (A)

(B)

(C)

)LJXUH6WDJHVRIFDSSLQJDWUHQFKDW3=52%XU\DNRYND )LJXUH ±WKHZDVWHLVFDSSHGZLWKDQHYHQOD\HURIVDQG % DIXUWKHUOD\HURIVDQGLVSXW over an intermediate layer of clay; (C) finished trench with grass capping.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 53  0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV (i) Quantity of radioactive waste Prior to 1997 the volume of radwaste disposed at Buryakovka was determined by the number of truck loads, and the radwaste mass was calculated using the estimated waste density. In 1997 truck scales were installed at Buryakovka, allowing the mass of radioactive waste to be measured directly (for details see Appendix A).

(ii) Radiation characteristics of waste The total and specific activity of each batch of radioactive waste arriving at Buryakovka is determined according to the technique developed by the State Specialised Enterprise “Radek” [UDK NPO Pripyat]. The exposure dose rate for each waste batch is measured using DP-5V and MKC-01R dosimeters. The total activity of the waste is determined from the measurements of exposure dose rate according to the following formula:

     (1)

where; A is total activity of the waste, mCi LVWKHPDVVRIWKHUDGLRDFWLYHZDVWHLQWKHWUXFNWRQQHV LVDYHUDJHH[SRVXUHGRVHUDWHP5K

See Appendices A and C for details.

Sampling of radioactive waste in trucks is performed twice per month. Five samples are taken from each truck, at uniform intervals throughout the truck load. Correlation ratios between Caesium-137 activity and the activity of other radionuclides, for Trench 25, have been estimated by IGS using the results from the radiometric analysis of the samples (see Appendix A for details). These empirical correlation ratios have been used to re-assess the contribution of individual radionuclides to the total activity contained in Trench 25.

Using the statistical distribution of the exposure dose rates measured for the waste batches, the statistical distributions of the specific activities of Caesium-137 and of transuranic elements have been determined for Trench 25.

Data relating to Trench 25 has been extrapolated in order to estimate the inventory of PZRO Buryakovka as a whole.

(iii) Data handling and storage Currently, the waste reception point at Buryakovka is equipped with a system of automated exposure dose rate measurement, with subsequent computer-aided recording, processing and documenting. The measured data are promptly transferred to the Regional Centre for radioactive waste recording at SSE Complex for inclusion in the radioactive waste register. The automated system of data measurement and handling has been developed by the State Industrial Union “Metrologiya” [GNPO Metrologia, 1998].

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 54 When radwaste is accepted for disposal at Buryakovka, the so-called ‘waste passports’ with basic characteristics are filled in for each batch. The main radionuclide characteristics are also transferred to a special radioactive waste register. An electronic database is currently being developed for the data on the register. Following analysis, the data on the radionuclide composition of the waste are added to the waste record.

To date, analysis of the results for waste disposal at Buryakovka between 1997 and 2000 has been performed. Full information relating to the disposed waste is only available for Trench No. 25, at which waste was disposed over the period 1997-1999. For the other trenches, processing of the results for the waste disposed prior to 1997 is currently being performed and the data is not yet available.

 &KDUDFWHULVWLFVRIZDVWHGLVSRVHGLQ7UHQFKDW%XU\DNRYND (i) Physical characteristics Waste was disposed at Trench 25 during the period 1997-1999. According to estimates made by SSE “Complex” the total waste volume disposed in Trench 25 is 42,000 m3, corresponding to a mass of 39,500 tonnes.

The physical characteristics of the waste within Trench 25 are shown in Table 16. The source of the waste is largely from the decontamination activities being performed within the Exclusion Zone, but also waste generated from operations at ChNPP, Unit Shelter and other enterprises within the Exclusion Zone (Table 17).

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SRW by composition % of the overall waste volume Construction waste 3.9 Metal waste 21.0 Soil, sand 47.8 Reinforced concrete 16.0 Other wastes 11.3

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 55 7DEOH6RXUFHVRIUDGLRDFWLYHZDVWHGLVSRVHGDW7UHQFK%XU\DNRYND DFFRUGLQJ WR66(&RPSOH[HVWLPDWLRQV

SRW Supplier SRW Source SRW Percentage, % State Special Enterprise Land decontamination, 91.8 “Complex” building demolition, treatment of unauthorised waste accumulations, etc. ChNPP Land decontamination, 6.1 operational waste (contaminated clothes, etc..) Unit Shelter Premises decontamination, 2 operational waste (contaminated clothes, etc..) Other enterprises Contaminated equipment 0.06 (“Chernobylservis”, (substation transformer, “Chernobylles”, Ministry of clothes, etc.) Foreign Affairs, etc.)

(ii) Radiation characteristics The inventory of waste for Trench 25 according to assessments made by SSE “Complex” is presented in Table 18. The analysis of the results for Trench 25, showed that the activity of transuranic elements is 1.6% of the total activity. This value is close to that obtained by ISTC for radioactive wastes at the ChNPP Industrial Zone. Using this result, the total activity of transuranic elements in Trench 25 was calculated 10 WREH  Bq, with an average specific activity equal to 2.46 Bq/g (Table 18).

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Parameter Value Mass of waste, tonnes 39,500 Waste volume, m3 42,000 Average exposure dose rate within a distance of 35 0.1m, µSv/h Maximum exposure dose rate within a distance of 0.1m, µSv/h 3000 Total activity, Bq 6.06x1012 (Ci) (164) Average specific activity, Bq/g 153.5 Total activity of transuranic elements, Bq 9,7x1010 (Ci) (2.6) Average specific activity of transuranic elements, 2.46 Bq/g

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 56 The waste inventory for Trench 25 was re-assessed by IGS using data obtained from the analysis of samples that had been periodically taken from the waste batches prior to disposal (see Appendix A).

The correlation ratios between Caesium-137 activity and the activity of other radionuclides obtained experimentally from the analysis of samples for Trench 25 are shown in Table 19. The sample correlation ratio for the sum of transuranic elements corresponds to the theoretical correlation ratio for ChNPP/Unit 4 fuel. The sample correlation ratios for the transuranic elements also correspond well with the correlation ratios specified within the instruction received by Buryakovka developed by SSE “Radek” [UDK NPO Pripyat]. However, there is a significant discrepancy between the values for the correlation ratio for Sr-90 specified in the instruction [UDK NPO Pripyat] and obtained experimentally from the samples. The experimental sample correlation ratio for Sr-90 is close to the theoretical correlation ratio based on the data for ChNPP/Unit 4 fuel. On the basis of these results, it has been judged that a more accurate assessment of the radionuclide composition of waste within Trench 25 would be obtained by using the experimental correlation ratio for Sr-90 as opposed to the value specified in instruction [UDK NPO Pripyat].

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Radionuclide Trench # 25 Sample “Instruction for Ukrainian Scientific Experimental Data solid waste, Research Institute of received by Agricultural Works Buryakovka, Data (based on fuel Activity correlation for Unit Assessment” 4/ChNPP) Data Ratio, Dispersion Sample Ratio, % Ratio, % % number 1 2 3 4 Caesium-137 100 100 100 Strontium-90 87 65 57 44 82 Plutonium-238 0.47 0.001 48 0.49 0.7 Plutonium-239 + 1.21 0.02 48 1.37 1.1 Plutonium-240 Americium-241 1.58 0.02 45 1.39 1.4 Plutonium-241 Not 64 48 defined Alpha-emitters 3.2 3.7 3.2 transuranic elements

The average and maximum specific activities of the various radionuclides within the waste samples for Trench #25 are presented in Table 20. It should be noted that the average value for Caesium-137 specific activity within the waste samples for trench #25 (79 Bq/g) agrees with the value determined from the measurements of exposure

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 57 dose rate (Average specific activity of Cs-137 = 153.5Bq/g * 50% = 77 Bq/g; from Table 18 and using the assumption that the Cs-137 contribution to the total activity of waste is 50 % [UDK NPO Pripyat]).

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Radionuclide Number of Average Specific Maximum samples Activity, Bq/g Specific Activity, Bq/g Caesium-137 68 79.3 610 Strontium-90 57 55.4 630 Plutonium-238 47 0.41 2.75 Plutonium-239 + 48 0.92 5.9 Plutonium-240 Americium-241 45 1.24 9.63

The contributions of the individual radionuclides to the total activity of the waste in Trench 25 were re-assessed using the experimental correlation ratios given in Table 5. The theoretical correlation ratio for ChNPP/Unit 4 fuel was used for Plutonium-241 (Table 19). The results are shown in Table 21. The average specific activity of Cs-137 was determined from the SSE “Complex” data in accordance with the measurements of exposure dose rate. Using the experimental correlation ratios it was found that the specific activity of the waste in Trench 25 (calculated from sum of specific activities of Cs-137, Sr-90, Pu-241 and transuranic elements) corresponded to 238% of the Cs- 137 specific activity.

It can be seen that the results from the re-assessment of the average specific activities of the radionuclides (Table 21) differ from the initial assessments performed by State Special Enterprise “Complex” presented in Table 18.

The maximum specific activities of the radionuclides in the radioactive waste in Trench 25 are presented in Table 21. These were assessed using the maximum values of exposure dose rate measured for the waste batches. It can be seen that the maximum specific activities exceed the average values by more than 200 times.

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Parameter Value Total activity of waste Caesium-137, Bq 3.0x1012 (Ci) (81) Sum of Caesium-137, Strontium-90, Plutonium-241, 7.1x1012 Transuranic elements , Bq (193) (Ci) Transuranic elements, Bq 9.6x1010 (Ci) (2.6) Average specific activity of waste Caesium-137, Bq/g 77 Sum of Caesium-137, Strontium-90, Plutonium-241, Transuranic elements, 183 Bq/g

Transuranic elements, Bq/g 2.5 0D[LPXPVSHFLILFDFWLYLW\RIZDVWH (on the basis of max. exposure dose rate 5 Sv/h) Caesium-137, Bq/g 27 750 Sum of Caesium-137, Strontium-90, Plutonium-241, Transuranic elements, 66 000 Bq/g Transuranic elements, Bq/g 530

(iii) Waste classification According to the maximum specific activity of transuranic elements of 530 Bq/g (Table 21) some of the radioactive waste within Trench 25 is within the long-lived category according to the IAEA classification.

It should be noted, that according to the current radioactive waste acceptance criteria for Buryakovka (exposure dose rate up to 1R/hour with transuranic element content up to 2 % of the total activity), the disposal of waste containing up to 2220Bq/g of transuranic elements is authorised (See Appendix E).

In order to assess the distribution of activity within the waste in trench #25, the statistical distribution of the SSE “Complex” data relating to the exposure dose rate measurements was studied. From the statistical distribution of the data, presented in Table 22, it can be seen that only a few single waste batches disposed in trench #25 would be defined as long-lived waste (according to the IAEA criterion of 400Bq/g of TRU).

It can be shown that IAEA long-lived waste (400Bq/g) is roughly equivalent to a dose rate of approximately 200 mR/h (Appendix E). Data on waste batches in Trench 25

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 59 with measured dose rates in excess of 200 mR/h are shown in Table 23. The total volume of such waste in trench 25 is 11m3 or 0.03% of the total volume.

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Waste batch Calculated Calculated Number of Percentage of exposure Caesium-137 specific activity waste batches total number, % dose rate specific activity, of transuranic mR/h Bq/g elements, Bq/g 0-1 0-55 0-1.8 3580 62 1-30 55-1700 1.8-53 2132 37 30-200 1700-11000 53-350 37 0.6 200-300 11000-17000 350-530 3 0.05 Total 5752 100

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Dose rate, Number of Volume, m3 Mass, kg Waste Source mR/h batches stream 200 1 3.00 1300 Construction ChNPP waste 220 1 4.00 3500 Construction Object waste Shelter 300 1 4.00 5870 Construction Object waste Shelter

More than 99% of the waste batches in trench #25 belong to the low-level waste category (Group 1 according to SPORO-85 with exposure dose rate < 30 mR/h. Intermediate-level waste (Group 2 according to SPORO-85) forms nearly 0.7 % of the total by volume.

 &KDUDFWHULVWLFVRIZDVWHGLVSRVHGDW%XU\DNRYNDDVDZKROH (i) Inventory of waste trenches Only the waste contained in Trench 25 is fully characterised. The characteristics of the waste contained in trenches 1 to 10 are unknown, but it may have originated from the Industrial Zone and thus contain wastes of higher activity than in trench 25. Trenches 11 to 20 are known to contain waste from destroyed villages and are likely to contain a similar inventory to trench 25 at the time of disposal. Trench 21 contains waste from Stroybaza and is expected to contain higher activity levels.

State Specialised Enterprise “Complex” data concerning the characteristics of waste disposed at Buryakovka as a whole are presented in Table 24.

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:DVWH&KDUDFWHULVWLF 9DOXH Mass of waste, kg 806.3x106 Waste volume, m3 590x103 Total activity, Bq 2.435x1015 (Ci) (65 000) Average specific activity, Bq/g 3020.0 Transuranic elements total activity, 39 x1012 Bq (1054) (Ci) Transuranic elements average 48.4 specific activity, Bq/g Physical composition Soil, construction waste, concrete, reinforced concrete, metal scrap

The SSE “Complex” value for the specific activity of radioactive waste, disposed at Buryakovka as a whole, is approximately 20 times higher than that for Trench 25. Assessment of the data performed by IGS indicates that this value for the specific activity for Buryakovka is a significant overestimate. One possible explanation is that the data in the Exclusion Zone waste inventory registers have not been corrected for radioactive decay. This fact leads to the systematic overestimation of activity as time progresses, which is particularly relevant to the waste disposed during the first few years after the accident when a considerable contribution to the waste activity was made by short-lived isotopes.

In addition, as identified in the report from SSE “Complex” to IGS, apparently some errors were made during the acceptance of radioactive waste at Buryakovka during the period 1990-1993,which contributed to the overestimation of the total activity.

A more realistic assessment of the activity of the radioactive waste disposed at Buryakovka as a whole has been performed by IGS, involving an extrapolation of the data on specific activity for Trench 25 (Table 21) for the other trenches. The estimates for Buryakovka as a whole are presented in Table 25.

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3DUDPHWHU 9DOXH Caesium-137 total activity, Bq 6.1 x1013 (Ci) (1660) Total activity from sum of Caesium-137, 1.5x1014 Strontium-90, Plutonium-241, Transuranic (3920) elements, Bq (Ci) Transuranic elements total activity, Bq 2 x1012 (Ci) (53) Average specific activity of Caesium-137, 77 Bq/g Specific activity from sum of Caesium-137, Strontium-90, Plutonium-241, 183 Transuranium elements, Bq/g Transuranic elements average specific 2.5 activity, Bq/g Long-lived waste volume assessment according to IAEA classification, m3 150 (0.026% of total quantity)

It should be noted that the characteristics of the waste disposed at Buryakovka during the first few years following the accident may differ from that disposed more recently. Waste disposed at Buryakovka up to 1990 is likely to have been more active, at the time of disposal, than the waste accepted during 1997-1999 when Trench 25 was being filled. This must be taken into account when interpreting the results given above for Buryakovka, which were obtained by extrapolating data relating to Trench 25.

(ii) Inventory of Contaminated Equipment Store In addition to the trench disposals there is an open-air store at Buryakovka for the temporary storage of contaminated machinery. The results from a preliminary survey of motor and tractor machinery, stored at the site, are presented in Table 26.

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Name of Construction, Number of Total Mass, Gamma exposure dose Mark Units tonnes rate, mR/h

1 ZIL-130,131,157 208 1144 0.07-0.9 2 GAZ-53,66 36 180 0.06-0.6 3 Fire-engine 17 119 0.06-0.2 4 URAL 31 186 0.05-0.8 5 LIAZ Bus 6 54 0.05-0.07 6 MoAZ scraper, grader 26 260 0.06-0.8 7 BRDM, BTR, BMP 47 564 0.06-0.36 9 BAT 9 225 0.05-0.5 10 IMR 27 540 0.05-20.0 Total Number: 407 3272

Assuming a density of steel of 7.8g/cm3 and that the contaminated machinery consists of 10% steel and 90% void, the total volume of contaminated machinery is 4190 m3. As calculated within the current project, for contaminated machinery the IAEA threshold for long-lived waste of 400 Bq/g of alpha emitting radionuclides is roughly equivalent to gamma-dose rate measurements of 120 mR/h. Thus all vehicles at Buryakovka are likely to correspond to IAEA category short-lived low and intermediate level waste (SL-LILW).

 $QDO\VLVRIUHOLDELOLW\RIGDWD With Buryakovka being an operating facility, the quality of the available radwaste data is better than for the other sites. Special attention has been paid to analysing the acceptance criteria and the methodology used to assess the inventory.

1. To date only data relating to trench #25 have been introduced into the State Specialised Enterprise “Complex” electronic database and processed. For the other trenches data processing and analysis are still in progress. From 1997 reliable data on the waste disposed at Buryakovka are available, however, prior to 1997, the data on the waste disposed at Buryakovka are unreliable and have not been corrected for radioactive decay.

2. In order to determine the waste inventory for Buryakovka as a whole, data relating to trench #25 is being extrapolated for the other trenches. However, it is expected that the characteristics of the radioactive waste disposed in the other trenches may deviate from that disposed at trench #25, because the waste originates from different areas of the Exclusion Zone and also the waste was disposed at different times after the accident.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 63 3. The methods used to determine the activities of radionuclides in the waste disposed at Buryakovka from measurements of exposure dose rate are, in general, accurate. The agreement of the average specific activity of Caesium-137 in the trench #25 obtained from exposure dose rate measurements (77 Bq/g) with the value obtained from the gamma-spectrometry of waste samples provided additional verification of the methods. However, the correlation ratios that define the individual radionuclide contribution to the total waste activity used, need revision. Considerable discrepancy in the correlation ratio for Strontium-90 as defined in instruction [UDK NPO Pripyat] and as obtained experimentally from the analysis of samples has been identified.

4. The methods used to determine the total and specific activities of waste disposed at Buryakovka assume that the waste is loose with a homogeneous composition. These methods are not valid for assessing the activity of solid radioactive waste which has surface contamination only. As a result of this, the total activity of waste disposed at Buryakovka has been apparently overestimated. Taking into account the proportions of the various waste types for trench #25 (Table 18), the overestimation in total activity for trench #25, as a result of the use of incorrect methods, could be more than 20 %.

5. The correlation ratios for radionuclides within different waste batches differ greatly. For trench #25 only a limited number of samples have been taken in order to determine the average values for the correlation ratios for the waste disposed as a whole. In order for a more accurate assessment of the average correlation ratios to be performed, analysis of the composition of waste in each batch would be required.

6. There is a serious uncertainty with the measurements of long-lived waste in trench 25. In order to estimate the share of the long-lived wastes, SSE Complex provided data on the statistical distribution of the dose-rate measurements for waste batches. Each batch is equivalent to a truck load and weighs between 1 and 6 te.

7. It has been reported by SSE Complex [V. M. Antopov, personal communication with D Bugai] that measurements corresponding to the waste batches with high activity levels, presented in Table 23, have not been verified, which is contrary to the acceptable practice. It is possible that the high dose-rates resulted from cross- contamination or other errors.

 ,GHQWLILFDWLRQRIIXUWKHUDFWLYLWLHVWRLPSURYHGDWDTXDOLW\ In order to improve the quality of the data relating to Buryakovka the following work needs to be performed:

1. The completion of the State Specialised Enterprise “Complex” electronic database for all disposal trenches at Buryakovka; 2. Surveys of the waste disposed at Buryakovka using methods similar to those used in the surveys performed of the PVLROs. 3. Improvement of the automated measurement system at the Buryakovka waste reception point:

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 64 - to allow the number of points where exposure dose rate is measured on the waste surface to be increased to 10-12; - to set up a laboratory for radiochemical analysis at PZRO Buryakovka; - to allow the use of differing methods for determining the waste activity for different kinds of materials as appropriate (equipment etc.).

Required improvements in the analytical methods:

1. In order to take into account the change in correlation ratios between the radionuclides as a result of radioactive decay and the accumulation of daughter products, correlation ratios should be regularly adjusted. Such a procedure is not provided for in the existing methods. 2. Experimental correlation ratios, obtained from the analysis of waste samples, should be used in the assessment of the contributions of individual radionuclides to the total activity. 3. Sampling of waste located within trenches other than trench 25 would greatly increase confidence in the previous measurements. This is especially relevant to trenches dating from the early days of Buryakovka’s operation, which are likely to contain wastes of higher activity. 4. It is necessary to correct estimates for wastes, which are not loose and homogenous. In order to do this, there is a need to gain further information on the physical composition of the wastes. 5. When laboratory analysis of samples is carried out in the future, it is desirable to carry out verification of the results in independent laboratories.

 )XWXUH3URVSHFWVIRU5DGLRDFWLYH:DVWH'LVSRVDODW%XU\DNRYND In November 1999 the State Specialised Enterprise “Complex” obtained a Nuclear and Radiation Safety Series Licence No. 000039, for the performance of activities associated with radioactive waste management. The licence provides for:

- Operation of Buryakovka; - Scheduled operations aimed at ensuring radiation safety of Podlesny and “3-rd Stage ChNPP”; - Scheduled operations aimed at ensuring radiation safety of PVLROs and radioactive waste re-disposal under the projects approved by the Administration; - Specialised laundry operation (decontamination of working clothes and personnel protection equipment).

Currently 24 of the 30 trenches at Buryakovka are full, 2 trenches are 90% full with the remaining 4 trenches being empty. Assuming each trench can contain 23-35 thousand m3 of radioactive waste prior to compaction, the remaining capacity of the trenches is approximately 100-120 thousand m3. In addition there is the possibility of storing up to 40 thousand m3 of radioactive waste in the “Jupiter” Storage Facility. Thus in total the remaining capacity for the disposal of radioactive waste at Buryakovka is ~140-160 thousand m 3.

Possible options being considered for increasing the available capacity for radioactive waste disposal at Buryakovka are as follows:

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 65 - Construction of a modular type reinforced concrete storage facility; - Construction of trench type near-surface storage facilities similar to the existing storage facilities, but larger in size; - Construction of trench type near-surface storage facilities between the existing trenches.

A reinforced concrete storage facility, similar to the first option listed above, has been developed under the Kiev Institute “Energoproekt” project. In relation to this facility, it is necessary to perform some modifications taking into account additional regulatory requirements and also to perform ecological expertise. It is possible to dispose of up to 100 thousand m3 of radioactive waste at such a facility.

In relation to the option of trench type near-surface storage facilities between the existing trenches, basic engineering solutions have been developed. It would be possible to dispose of up to 900 thousand m 3 of radioactive waste using this type of facility, corresponding to 15 trenches each with a capacity of 60 thousand m3.

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The acceptance criteria for the disposal of radioactive waste at Buryakovka are as follows:

- solid radioactive waste of Chernobyl origin; - short-lived radioactive waste, groups 1 and 2 (from 0.03 mR/h to 1000 mR/h at a distance of 0.1m); - HPLWWLQJUDGLRQXFOLGHVXSWRRIWKHWRWDODFWLYLW\

According to this criteria the disposal of waste containing up to 2220Bq/g of transuranic elements is authorised for Buryakovka (See Appendix E). This exceeds the limit for long-lived radioactive waste according to the IAEA classification (400 Bq/g). Hence the acceptance criteria do not conform to accepted international practice for near-surface disposal. In addition, Buryakovka was only intended for the disposal of low and intermediate level waste. It was not designed for the burial of long-lived waste.

It is recommended that the radioactive waste criteria for Buryakovka be revised in line with international accepted practice as follows:

1. Instead of specifying the maximum percentage contribution of transuranic elements to the total radioactive waste activity, it is necessary to regulate the maximum specific activity of transuranic elements in the waste. The limit for the specific activity of transuranic elements should comply with Ukrainian regulations on radiation safety and take into account the accepted international practice and IAEA recommendations; 2. The upper limit for exposure dose rate (currently 1000 mR/h) needs to be lowered WRWDNHLQWRDFFRXQWWKHW\SLFDOFRUUHODWLRQEHWZHHQH[SRVXUHGRVHUDWHDQGWKH  specific activity for Chernobyl radioactive waste. An exposure dose rate of about 200 mR/hour for Chernobyl radioactive waste corresponds to an upper limit for transuranic element activity of 400 Bq/g (see Appendix E).

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 66  *HQHUDO'HVFULSWLRQRI39/52V The following temporary waste dumps (PVLROs - Points of Radioactive Waste Interim Localisation) are located within the ChNPP Exclusion Zone:

- Ryzhy Les (Red Forest) - Stantziya Yanov (Yanov Station) - Neftebaza (Oil Facility) - Peschannoe Plato (Sandy Plateau) - Stroybaza (Building base) - Pripyat - Kopachi - Chistogalovka

The PVLROs were constructed between 1986 and 1987 by civil defence troops when carrying out decontamination work around Unit 4 ChNPP and the adjoining area. The waste dumps have no protective engineered barriers and were constructed without regard to the local hydrogeological conditions. They fail to comply with the Ukrainian regulations on the safe storage of radioactive waste.

To date only about 300 Ha, or 28%, of the total area occupied by PVLROs in the ChNPP Near Zone has been surveyed. The total number of waste dumps (trenches and mounds) that have been surveyed is 463. The unsurveyed area in the Near Zone occupies an area of about 800 Ha (72% of the total) and, assuming an average trench density equal to that in the surveyed area has been estimated to contain about 1,200 waste dumps. A summary of the surveyed and unsurveyed PVLRO Sectors in the Near Zone is given in Table 27, and the dates and organisations which performed the surveys are listed in Table 28. The layout of the main PVLRO sectors is illustrated in Figure 2 (see also Figure 23).

PVLRO Surveyed areas Unsurveyed areas Sector Area, Ha Sector Area, ha

“Staraya Stroybaza” 1.1-1.4 186 “Ryzhy Les” 2.1 96 2.2-2.6 58

“Stantziya Yanov” 3.1+2.3, 3.5 51 3.2-3.4, 3.6- 247 3.7 ”Neftebaza” 5.1-5.3 72 “Peschannoe Plato” 6.0 78 “Novaya Stroybaza” 1.5 120 “Stantziya Semikhody” 45 “Kopachi” 125 TOTAL   (28%) (72%)

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 67 PVLRO Sector Year Organisation Ryzhy Les 2.1 1992 Scientific Institute of Industrial Technologies (NIPIPromtechnolo gii, Moscow) Stantziya Yanov 3.1 and 2.3 1993 Scientific and Technical Centre “KORO” Neftebaza 5.1, 5.2 and 5.3 1994-5 Scientific and Technical Centre “KORO” Peschannoe Plato 6.0 1998 Scientific and Technical Centre “KORO” Stantziya Yanov 3.5 1999 Scientific and Technical Centre “KORO”

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In addition to the unsurveyed PVLROs in the Near Zone, there are PVLROs Chistogalovka and Pripyat which currently have not been systematically surveyed and fall outside of the boundaries of the ChNPP Near Zone.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 68 Radioactive waste within the PVLROs is concentrated within disposal trenches and mounds, but also the surface layers of soil over the entire area of the PVLROs are contaminated. For the surveyed PVLROs analysis of the data relating to soil contamination has focussed on the surface soil layer (0-0.05m depth) and the near- surface soil layer (0.05-0.5m depth). The distribution of radionuclides within the soil is the result of the following:

- residual contamination remaining following the post-accident decontamination activities, and; - radionuclide migration (by wind and vertical migration within the soil).

The volumes and characteristics of waste in the “near-surface” soil layer were not investigated for the PVLROs surveyed most recently (e.g. [TACIS, 1995, and OSAT, 1999a]). However, consistent with the reports produced by the Institute NIPIPromtechnologii and Scientific and Technical Centre “KORO”, the volumes of waste in this layer are likely to be relatively large.

The PVLROs are currently covered in vegetation, including trees, bushes and grass. This vegetation is known to be contaminated but no systematic survey has been performed. Some experimental data on the radionuclide accumulation in vegetation are available for the PVLRO Ryzhy Les [Kashparov, 1999, and Bugai et al, 2000b].

 6XUYH\HG39/52V  0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV (i) Methods used to assess specific activity of waste The methods used during the survey of the PVLROs performed by NIPIPromtechnologii and the Scientific and Technical Centre “KORO” are described in detail in Appendix A. Gamma dose rates were measured inside boreholes drilled into the waste dumps. The caesium-137 specific activity of the waste was calculated from the measurements of gamma dose rate using an empirical formula (see Appendix A). Correlation coefficients were then used to calculate the specific activities of the other radionuclides present in fuel-containing waste.

Previous assessments of the waste inventory of the surveyed PVLROs [Ovcharov et al, 2000] focussed on the concentrations of caesium-137, strontium-90, and the sum of plutonium-239 and plutonium-240. Within the current project the waste inventory of the PVLROs has been re-assessed taking into account the contribution of plutonium-241, plutonium-238, and americium-241 in addition to the above radionuclides. Inclusion of these additional radionuclides has resulted in significant changes to the estimated beta-activity and, in particular, the total alpha-activity.

The revised calculations of the waste inventory of the PVLROs were performed by the Scientific and Technical Centre “KORO”, based on consultations with the Institute of Geology Sciences and the recommendations of B.A. Kashparov [IGS, 1999].

Correlation ratios obtained from experimental sampling data (Table 29, Column 2) were used where available. However, for plutonium-241 and americium-241, where

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 69 no experimental data relating to the correlation coefficients were available, data relating to these radionuclides obtained by the Institute for Agricultural Radiology for ChNPP Unit 4 fuel were used (Table 29, Column 3). As Table 29 shows, the experimental correlation ratios obtained by the Scientific and Technical Centre “KORO” for the other plutonium isotopes are close to the values for Chernobyl Unit 4 fuel calculated from the data provided by the Institute for Agricultural Radiology (UkrNIISKhR).

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Radionuclide STC “KORO” data obtained Institute for Agricultural Radiology from PVLRO waste samples data for ChNPP Unit 4 fuel 137Cs 1.0 1.0 90Sr 0.73 0.86 134Cs 2.49E-2 3.7E-2 154Eu 1.15E-2 3.1E-2 155Eu 0.87E-2 1.5E-2 238Pu 0.5E-2 0.55E-2 239,240Pu 1.22E-2 1.2E-2 241Pu - 0.54 241Am - 1.05E-2

(ii) Methods used to estimate volumes of waste The volumes of waste in the trenches and mounds were estimated from the dimensions of each of the waste dumps. The dimensions of the waste dumps were determined from the gamma-logging of boreholes.

For Sectors 5.2 and 5.3 of PVLRO Neftebaza the volume of waste in the surface soil layer (0-0.05m) was estimated from gamma dose-rate measurements made over a horizontal 10x10 m grid [STC KORO, 1995a]. For Sector 5.3 of PVLRO Neftebaza the volume of waste in the near-surface soil layer (0.05-0.5m) was also estimated from dose rate measurements over a horizontal 5x5m grid at 5 depth intervals, to a depth of 1m. Each grid cell, of known volume, was assigned a single value of exposure dose rate, and based on this data the volume of waste in each Sector was determined. The methodology is described in detail in Appendix A.

For the other surveyed PVLROs (except Neftebaza), surface gamma-dose rates and beta-contamination were measured. Where the equivalent dose rate exceeded 3µSv/h the surface soil layer was classified as radioactive waste. The volume of waste in the surface layer was estimated from the area of the Sector and assuming a thickness of contaminated soil of 5cm.

The volumes of waste in the near surface layer, for PVLROs other than Neftebaza, were only estimated for Ryzhy Les. For Ryzhy Les, the volume of waste in the near- surface layer was back-calculated from estimates of total activity given in [NIPIPromtechnologii, 1992] as follows:

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 70 1. It was assumed that the specific activity and density of the waste in the near- surface layer were the same as for the waste dumps. This assumption was based on the fact that the near-surface layer contains some of the initially contaminated soil that was not removed during the decontamination work, with that which was removed being placed into the waste dumps.

2. Given the above assumption the following formula applies:

Volume of waste in near-surface layer = Activity of waste in near-surface layer Volume of waste in waste dumps Activity of waste in waste dumps

3. Estimates of the total activity of the waste in the near-surface layer and in the waste dumps were given in [NIPIPromtechnologii, 1992]:

- Estimated activity in the surface soil layer (0-0.05m) = 7% of the total activity in Sector 2.1. - Estimated activity in the near-surface soil layer (0.05-0.5m) = 10% of the total activity in Sector 2.1. - Remaining activity (83% of the total) is in the waste dumps.

Ratio of total activity of waste in the near surface layer to that in the waste dumps is equal to 10% / 83%

4. Volume of waste in the near surface layer = 10%/ 83% × volume of waste in dumps = 17,000 m3.

 6HFWRURI39/525\]K\/HV (i) General Description of Sector 2.1 of Ryzhy Les Sector 2.1 of Ryzhy Les is situated at 1.5km to the west-southwest of the Chernobyl NPP. The area of the Sector is 96 Ha (Figure 24). The ground within the Sector is largely flat varying in height between 113 and 115m above the level of the Baltic Sea.

The PVLRO was created in 1987 by the Civil Protection Troops during the decontamination of the ChNPP and surrounding area. The area was bulldozed and the radioactive wastes were disposed in-situ in trenches and mounds. The wastes consist of the removed upper layer of contaminated soil and contaminated tree remains, grass and construction waste from demolished cottages. A 0.5m-thick layer of non- contaminated sandy soil was spread over the entire area of the Sector covering the waste.

Pine trees were planted on the PVLRO between 1989 and 1990. As a result, the PVLRO is now covered with a 10-year old pine forest, with some birch and bushes (Figure 25).

Sector 2.1 of Ryzhy Les was surveyed in 1991-1992 by the Institute of Industrial Technology [NIPIPromtechnologii, 1992]. It was the first PVLRO Sector within the Chernobyl Exclusion Zone to be surveyed. The following main radiation sources within the Sector were identified:

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 71 1. Trenches and mounds containing radioactive materials. In total, 49 trench-type burials and 8 mounds were detected. These trenches and mounds were the result of the decontamination work performed in 1987. The dumps are 24m - 440 m long, 2-3 m wide, and 2-2.5m deep. 2. Surface soil layer (0-0.05m depth) over the whole Sector. Radioactivity in the surface soil layer is the result of the disturbance of the ground by vehicles, the migration of radionuclides from the neighbouring contaminated Sectors (e.g. wind-blown dust), and the vertical migration of radionuclides. 3. Near-surface soil layer (0.05-0.5m depth). Contamination within this layer is concentrated in certain ‘hot-spots’. These hot spots are the result of residual contamination that was not removed during the decontamination work, and was then covered over by soil.

In addition vegetation (pine trees, birch, and bushes) growing on the PVLROs is contaminated as a result of activity intake from the dumps.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 72 )LJXUH&XUUHQWVWDWHRIYHJHWDWLRQDW6HFWRURI³5\]K\/HV´

The soils within the PVLRO consist of aeolium and alluvial Quaternary Sand Deposits. According to the data obtained during the 1991-2 survey of the site, the depth of the groundwater table in Sector 2.1 varies between 0.5 and 3 m. Ground at the western end of the Sector is seasonally flooded (after snow-melt in spring and following autumnal rainfall). The majority of trench disposals (37 out of 49) and 2 out of the 8 mounds are flooded to some degree by groundwater. In some of the trenches the groundwater table is 1-1.5m above the bottom of the waste.

The direction of groundwater movement is from the south-west to north-east, with a groundwater gradient of (1-2)×10-3 m/m. Groundwater flows towards the Pripyat Inlet, situated 1.5km from the north-west border of the Sector. According to estimates made by NIPIPromtechnologii, the groundwater velocity in the upper part of the aquifer is 10-20 m per year.

(ii) Physical characteristics of waste In the report produced by NIPIPromtechnologii [NIPIPromtechnologii, 1992] Sector 2.1 has been further subdivided into two sub-sectors D-1 and K-1, of areas 76Ha and

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 73 20 Ha, respectively. Sub-sector K-1 corresponds to the western end of Sector 2.1, with Sub-sector D-1 containing 45 out of the 49 trenches. Detailed data on waste volumes and characteristics contained in the report [NIPIPromtechnologii, 1992] only relate to the sub-sector D-1, with the total quantity of waste in D-1 and K-1 only being described in terms of the mass.

Data on the volumes and the physical properties of the waste contained in trenches and mounds in Sector 2.1 of Ryzhy Les are shown in Table 30. These were determined by extrapolation of the data relating to sub-sector D-1 obtained during the 1992 survey.

Measurements in 1992, of the surface contamination of Sector 2.1 of “Ryzhy Les” are as follows:

- average value of equivalent dose rate is 27µSv/hour; - beta-contamination is up to 70,000 particles/(min cm2).

Accurate estimations of the volumes of waste in the surface and near-surface soil layers were not provided in the initial report of the Institute of Industrial Technology [NIPIPromtechnologii, 1992]. Based on the measurements of surface contamination the surface soil layer was designated as radioactive waste. Assuming a thickness of 5cm for the surface layer, and a total area of contaminated soils of 87 Ha (96 Ha in total, minus area occupied by disposal dumps, which is about 9%), the volume of waste in the surface layer was estimated as 44,000 m3.

The volume of waste in the near surface layer was estimated to be 17,000 m3 based on the estimated ratio of the total activity of waste in the near-surface layer compared to the total activity of waste in the waste dumps (see Section 3.6.1).

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Parameter Value Total volume of waste, m3 139,000 Total mass of waste, tonnes 222,000 Composition of waste Mainly soil and vegetation. Some construction and household waste from demolished buildings. Physical composition soil (50%), vegetation (50%) (expert estimate in % of volume) (*) Note: (*) – estimated by Scientific and Technical Centre “KORO”

(iii) Radiation characteristics of waste Data on the specific and total activities of the waste in trenches and mounds in Sector 2.1, following re-assessment by STC KORO taking into account a complete list of the main dose-contributing radionuclides, are shown in Table 32. It should be noted that detailed data relating to the waste characteristics contained in the report produced by the Institute of Industrial Technology [NIPIPromtechnologii, 1992] only relate to the

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 74 sub-sector D-1. Estimations of the waste characteristics for all of Sector 2.1 have been made by extrapolating data for D-1.

7DEOH9ROXPHRIZDVWHLQVXUIDFHDQGQHDUVXUIDFHVRLOOD\HUVLQ6HFWRU³5\]K\ /HV´ Sources of Radioactivity Total Total mass, volume, m3 tonnes Surface soil layer (0-0.05 m) 44,000 (*) 70,000 (*) Near-surface soil layer (0.05-0.5 m) 17,000 27,000 Total 61,000 97,000 Note: (*) – estimated by Scientific and Technical Centre “KORO”

7DEOH5DGLDWLRQFKDUDFWHULVWLFVRIZDVWHLQWUHQFKHVDQGPRXQGVLQ6HFWRU ³5\]K\/HV´ IRU\HDU Parameter Value

(TXLYDOHQWGRVHUDWHLQVLGHZDVWHGXPS $YHUDJHGRVHUDWHLQVLGHZDVWHGXPS 6YKRXU 190 Maximum dose rate inside storage facility (taken 912 IURPDYHUDJHYDOXHVDWVSHFLILFGXPSV  6YKRXU 7RWDODFWLYLW\RIZDVWH Caesium-137, Bq 1.2 1014 (Ci) (3330) Total of caesium-137, strontium-90, plutonium-241, 2.9 1014 TRU (transuranic elements) , Bq (Ci) (7790) TRU (plutonium-238,239,240, americium-241), Bq 2.6 1011 (Ci) (70) $YHUDJHVSHFLILFDFWLYLW\RIZDVWH Caesium-137, Bq/g 550 Total of caesium-137, strontium-90, plutonium-241, 1270 TRU, Bq/g TRU, Bq/g 11.5

0D[LPXPYDOXHVRIDYHUDJHVSHFLILFDFWLYLW\FRUUHVSRQGLQJWRLQGLYLGXDO GXPSV Caesium-137, Bq/g 2670 Total of caesium-137, strontium-90, plutonium-241, 6250 TRU, Bq/g TRU, Bq/g 56 Note: (*) – data provided for sub-sector D-1 of the PVLRO Sector 2.1 “Ryzhy Les”

It has been estimated that the surface soil layer (0-0.05m) has 7% of the total activity in Sector 2.1 and the near-surface soil layer (0.05-0.5m) has 10% of the total activity, with the activity in disposal trenches making up the remaining 83% of the total [NIPIPromtechnologii, 1992].

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 75 In addition, the radionuclide accumulation in vegetation at Trench 22 (surface area ~ 420 m2) of Ryzhy Les has been estimated as follows [Kashparov, 1999]:

- Total activity of Sr-90 in birch and pine trees (wood + leaves/needles) is 350 MBq - Total activity of Cs-137 in birch and pine trees (wood + leaves/needles) is 37 MBq

(iv) Waste classification Waste in Sector 2.1 of Ryzhy Les largely consists of short-lived low and intermediate level waste according to the IAEA classification. From Table 4 it can be seen that the average specific activity of transuranic elements (TRU) for individual trenches in sub- sector D-1 does not exceed 56 Bq/g. This is lower than the limit for long-lived waste of 400Bq/g of TRU, according to the IAEA classification. However, according to the data of the Institute of Industrial Technology [NIPIPromtechnologii, 1992], maximum equivalent dose rates measured inside trenches are often 10-20 times higher than the average dose rate values. Thus within individual trenches there may be localised regions where the specific activity of the waste exceeds 400 Bq/g. Three out of the total of 45 trenches within the sub-sector D-1 have been identified as possibly containing localised regions of long-lived waste (Table 33).

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Number of Maximum dose Maximum specific Maximum specific trench rate inside trench, activity of 137Cs, activity of TRU, Bq/g mR/hour Bq/g  642 18700 390  802 23400 490  976 28500 600

The estimated quantity of long-lived waste in trenches T-14, T-24 and T-28 is more than 31m3 and less than 855m3. Taking the average value of 443 m3, the percentage of long-lived waste in sub-sector D-1 is 0.45%.

However, an accurate assessment of the total volume of long-lived waste in the individual trenches, as well as summed over the whole Sector, is not possible:

1. The measurements made during gamma-ray logging only characterise a cylinder of soil with a 50cm radius and a height of 10 cm. Measurements from such a small volume are unlikely to be representative of the waste within the trench as a whole. 2. The report [NIPIPromtechnologii, 1992] does not contain the statistical distribution of gamma-probing results for the individual waste dumps (with only the average and maximum dose rates being presented for each trench).

 6HFWRUVDQGRI39/52³6WDQW]L\D

Within Sectors 3.1 and 2.3 there are 38 trench-type waste burials (Figure 26). The trenches vary from 8 to 100 m in length, 1.5 to 10 m in width, and 1.5 to 2.0 m in depth. The wastes contained in the trenches consist of the upper layer of the soil removed during decontamination work, tree remains and construction waste from the demolition of cottages. At present, the PVLRO is covered with 8-10 year-old pine trees.

Sectors 3.1 and 2.3 of “Stantziya Yanov” were surveyed in 1993 by STC “KORO” [STC KORO, 1993]. According to the survey the groundwater table is at a minimum depth of 1.8m and an average depth of 3 m below the surface. At the time of the survey, the minimum depth of the groundwater table below the base of the trenches was 0.13 m. The unsaturated zone consists of homogeneous layers of fine-grained and medium-grained sands separated by clay layers (up to 0.6m thick) detected at depths between 1.15 and 3.5m. The direction of groundwater movement is from the south- west to the north-east, with a groundwater gradient of 2.10-3 - 3.10-3. The groundwater flows towards the Prypyat Inlet at a distance of 1.5km.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 78 (ii) Physical characteristics of waste According to the data obtained during the 1993 survey [STC KORO, 1993], the volume of waste contained within the trenches is 16,400 m3, with a mass of 26,200 tonnes. The waste contained within the trenches consists of largely soil, but there is also some construction waste and tree remains (Table 34).

The volume of waste in the surface soil layer was estimated from measurements of surface contamination. Measurements in 1993, of the surface contamination were as follows:

- average exposure dose rate of 0.35mR/hour - maximum exposure dose rate of 1.5mR/hour - soil surface β-contamination of 60-4,000 particles/(cm2*min).

The maximum volume of contaminated soil within the surface layer was estimated as 8,000 m3 or 12,800 tonnes. The near-surface soil layer was not surveyed.

7DEOH3K\VLFDOFKDUDFWHULVWLFVRIZDVWHLQGLVSRVDOWUHQFKHVLQ6HFWRUVDQGRI ³6WDQW]L\D

Parameter Value Volume of waste in trenches, m3 16,400 Mass of waste in trenches, tonnes 26,200 Waste composition Soil, construction waste, wood Physical composition Soil (70%), plant material (expert evaluation, volume %) (20%), metal (5%), concrete/ brick (5%)

(iii) Radiation characteristics of waste From the measurements of exposure dose rate obtained during the 1993 survey and the estimates of the waste mass, the total activity of the waste in the trenches was estimated to be 3.4×1012 Bq (89 Ci), for 1993 (see Appendix A). The estimated waste activity and radionuclide composition for waste contained in the trenches are shown in Table 35.

The average specific activity of 137Cs in the surface layer was estimated to be 16Bq/g.

(iv) Waste classification The waste consists of short-lived low and intermediate level waste, in accordance with the IAEA classification.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 79 7DEOH5DGLDWLRQFKDUDFWHULVWLFVRIZDVWHFRQWDLQHGZLWKLQWKHWUHQFKHVLQ6HFWRUV DQG³6WDQW]L\D

Parameter Value Equivalent dose rate within waste trenches Average equivalent dose rate in trenches, µSv/h 15.8 Maximum equivalent dose rate in trenches, µSv/h 43.6 Total activity of waste in trenches Caesium-137, Bq 1.4×1012 (Ci) (36) Total of caesium-137, strontium-90, plutonium- 3.4×1012 241, TRU, Bq (89) (Ci) TRU (Plutonium-238, 239, Americium-241), Bq 2.1×1010 (Ci) (0.54) Average specific activity of waste in trenches Caesium-137, Bq/g 49 Total of caesium-137, strontium-90, plutonium- 120 241, and TRU, Bq/g TRU, Bq/g 0.75 Maximum value of average specific activity for individual trenches Caesium-137, Bq/g 100 Total of caesium-137, strontium-90, plutonium- 246 241, and TRU, Bq/g TRU, Bq/g 1.5

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 80  6HFWRUVDQGRI39/52³1HIWHED]D´

(i) General Characteristics of Sectors 5.1, 5.2 and 5.3 of PVLRO “Neftebaza” PVLRO “Neftebaza” is located on the right-bank of the River Pripyat along the southern coast of the Pripyat Inlet (see Figure 27 and Figure 28). Approximately one half of Sector 5.1 of the PVLRO is situated on the Pripyat floodplain, at a height of 107-108m above the Baltic Sea. Sectors 5.2 and 5.3 and the remainder of Sector 5.1 are situated on the first terrace above the flood plain at a height of 114-116m (Figure 2).

The total area of the PVLRO is 70 Ha. Within the PVLRO there are 221 disposal trenches and 4 disposal mounds. The waste dumps vary from 1.5 to 3.5 m in depth, 3 to 50 m in width, and 7 to 160 m in length. The waste dumps contain contaminated soil, demolished reinforced-concrete structures from the River wharf, rubble and wood.

The groundwater table is at a depth of 0.5 – 1.5 m in the floodplain area and 5.7 – 10 m in the area of the terrace. The direction of movement of groundwater is from the south-west to north-east on the floodplain and south-east to the north-west on the terrace. The groundwater gradient is estimated to be 0.6x10-3 – 4x10-3. For Sector 5.1 some of the waste dumps are in direct contact with the Pripyat Inlet. For the other Sectors the distance from the waste dumps to the Pripyat Inlet varies between 50 and 1000 m.

Sectors 5.1, 5.2 and 5.3 of PVLRO “Neftebaza” were surveyed in 1994-5 by the Scientific and Technical Centre KORO [STC KORO, 1994 & 1995a]. From observations made during the survey, the waste dumps can be divided into three categories according to the state of flooding:

- Constantly flooded – 19 waste dumps. - Flooded seasonally during periods of high water – 30 dumps. - Not flooded – all the waste situated on the terrace and on the slope.

During the flood period of 1999 all the dumps in the floodplain were entirely flooded.

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)LJXUH9LHZRIXQILQLVKHGWUHQFKDW39/521HIWHED]D NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 82 (ii) Physical characteristics of waste Data on the volume and physical properties of the waste in the trenches and mounds at the PVLRO, obtained during the 1994-5 surveys [STC KORO, 1994 & 1995a], are shown in Table 36.

The distribution of waste in the waste dumps between the three Sectors is as follows:

- Sector 5.1 – 66,000 m3 or 106,000 tonnes; - Sector 5.2 – 27,400 m3 or 44,000 tonnes; - Sector 5.3 – 28,800 m3 or 46,000 tonnes.

From the gamma dose rate measurements across the surface of the facility (see Appendix A) the volume of waste concentrated in the surface soil layer was estimated as follows [STC KORO, 1995a]:

- Sector 5.2 – 8,400 m3 or 13,400 tonnes; - Sector 5.3 – 5,400 m3 or 8,600 tonnes.

The volume of waste in the surface soil layer was not estimated for Sector 5.1.

From the gamma dose rate measurements with depth in the soil, the volume of waste in the near-surface soil layer in Sector 5.3 was estimated to be 20,400 m3 or 32,600 tonnes. The volume of waste in the near-surface soil layer was not estimated for Sectors 5.1 and 5.2. See Table 37.

7DEOH3K\VLFDOFKDUDFWHULVWLFVRIZDVWHLQWUHQFKHVPRXQGVLQ39/52³1HIWHED]D´ 6HFWRUVDQG 

Parameter Value Total volume of waste, m3 120,000 Total weight of waste, tonnes 192,000 Waste characteristics Soil, construction waste, wood Waste physical components Soil (65%), plant matter (expert evaluation, volume %) (20%), metal (10%), concrete/ brick (5%)

7DEOH9ROXPHVRIZDVWHLQVXUIDFHDQGQHDUVXUIDFHVRLOOD\HUVLQ39/521HIWHED]D 6HFWRUVDQG

Sector 5.1 Sector 5.2 Sector 5.3 Volume of waste in surface soil layer /m3 * 8,400 5,400 Volume of waste in near-surface soil layer * * 20,400 /m3 * No data

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 83 (iii) Radiation characteristics of waste The total and specific activities of the waste contained in trenches and mounds were reassessed by STC KORO taking into account all of the main dose-contributing radionuclides (see Section 3.6.1). The results are shown in Table 38.

Measurements of gamma dose rate over the surface of Sectors 5.2 and 5.3 gave the following results (year 1995):

- average exposure dose rate is 0.3-0.5 mR/hour in the decontaminated area and 6.5 mR/hour in the contaminated area; - maximum exposure dose rate is 20 mR/hour; 2 - VXUIDFH FRQWDPLQDWLRQLVZLWKLQ±SDUWLFOHV FP min).

According to measurements of caesium-137 specific activity the total activity of Cs- 137 within the surface soil layer was estimated as (for 1995) [STC KORO, 1995a]: - Sector 5.2 – 26 Ci (1012 Bq), - Sector 5.3 – 6.4 Ci (0.2x1012 Bq).

For Sector 5.3, the maximum Cs-137 activity in the near-surface soil layer was estimated as 108 Ci (4x1012 Bq) (1995).

7DEOH5DGLDWLRQFKDUDFWHULVWLFVRIZDVWHLQWUHQFKHVPRXQGVLQ6HFWRUVDQG ³1HIWHED]D´

Parameter Value Equivalent dose rate in waste trenches/mounds Average equivalent dose rate in the waste dumps, 26.7 µSv/h Maximum equivalent dose rate in the waste 810 dumps, µSv/h Total waste activity Caesium-137, Bq 2.1 .1013 (Ci) (540) Total of caesium-137, strontium-90, plutonium- 4.9 .1013 241, and TRU, Bq (1280) (Ci) TRU (Plutonium-238, 239, Ameritium-241), Bq 3.7.1011 (Ci) (9.7) Average specific activity of waste Caesium-137, Bq/g 112 Total of caesium-137, strontium-90, plutonium- 262 241, and TRU, Bq/g TRU, Bq/g 3.3 Maximum value of average specific activity for individual waste dumps Caesium-137, Bq/g 353 Total of caesium-137, strontium-90, plutonium- 837 241, and TRU, Bq/g TRU, Bq/g 10.3

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 84 (iv) Waste classification According to the IAEA classification, the waste contained within the trenches and mounds can be defined as short-lived low and intermediate level waste (TRU content is < 400 Bq/g).

 39/52³3HVFKDQQRH3ODWR´6HFWRU (i) PVLRO “Peschannoe Plato” General Description PVLRO “Peschannoe Plato” is located on the right bank of the River Pripyat at a distance of 3.5 km to the north-west of the ChNPP. The western boundary of the PVLRO is adjacent to the outskirts of the city of Pripyat. The PVLRO occupies an area of 78 Ha (See Figure 2, Figure 29 and Figure 30). The ground surface is at a height of 110-114m above the level of the Baltic Sea.

The surface is covered by a 5-6m layer of sand, which was transferred from the Pripyat floodplain prior to the ChNPP accident. The surface is sparsely vegetated with grass and shrubs, which have grown up in the last 11 years. The eastern part of the PVLRO has been artificially sown with lines of willows. A few pine-trees and birches can also be found there.

The waste dumps were created in 1987. The waste contained within the dumps consists of contaminated soil, rubble, and small amounts of concrete from the decontamination of the land adjacent to ChNPP.

Sector 6.0 of the PVLRO was surveyed in 1998 by the Scientific and Technical Centre KORO [STC KORO, 1998]. 82 trench-type disposals and 8 surface mounds were found. The distance between trenches is approximately 50 m. The trenches vary from 11-700 m in length, 3-4 m in width, and 1.5-2.0 m in depth.

The waste dumps are not in contact with the groundwater and at the time of the survey the groundwater was 3.5-7m below the bottom of the waste. The movement of groundwater is from the south-west to the north-east, with a groundwater gradient of approximately 0.002. The groundwater flows towards the Pripyat Inlet, which is at a distance of 100 m.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 86 (ii) Physical characteristics of waste According to the data obtained during the 1998 survey [STC KORO, 1998] the volume of waste contained in trenches and mounds in Sector 6.0 has been estimated as 57,300 m3 or 91,700 tonnes. The volume and physical composition of the waste in the waste dumps are shown in Table 39.

In addition it has been estimated from measurements of gamma dose rate that the surface layer (0-5cm depth) consists of radioactive waste, with an estimated volume of 33,500 m3 (54,000 tonnes). Here, it is assumed that over 86% of the area has equivalent dose rates of more than 3 µSv/h [STC KORO, 1998].

From gamma-ray logging it was found that there is practically no contamination in the near-surface soil layer across the PVLRO area [STC KORO, 1998].

7DEOH3K\VLFDO&KDUDFWHULVWLFVRI:DVWHLQWUHQFKHVDQGPRXQGVLQ39/52 ³3HVFKDQQRH3ODWR´6HFWRU

Parameter Value Total waste volume, m3 57,300 * Total mass of waste, tonnes 91,700 Waste characteristics Contaminated soil, rubble (in small amounts) Physical composition Soil (~100%) (expert evaluation, volume %)

(iii) Radiation characteristics of waste The total and specific activities of the waste contained in trenches and mounds were reassessed by STC KORO taking into account all of the main dose-contributing radionuclides (see methodology, Section 3.6.1). The results are shown in Table 40.

Measurements of gamma dose rate taken in 1998 over the surface of Sector 6.0 gave the following results: - average equivalent dose rate in the Sector area was 4.7 µSv/h; - the range of equivalent dose rate is from background level to 10 µSv/h; 2 - VXUIDFH FRQWDPLQDWLRQLV±SDUWLFOHV FP min).

From the measurements of gamma-dose rate, the average specific activity of Cs-137 in the surface soil layer was estimated to be 22 Bq/g.

(iv) Waste classification According to IAEA classification, the waste in Sector 6.0 can be defined as short- lived low and intermediate-level waste (TRU content is less than 400 Bq/g).

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Parameter Value Equivalent dose rate in waste dumps Average equivalent dose rate in the waste dumps, 10.7 µSv/h Maximum equivalent dose rate in the waste 131 dumps, µSv/h Total activity of waste dumps Caesium-137, Bq 4.5 .1012 (Ci) (117) Total of caesium-137, strontium-90, plutonium- 1.0 .1013 241, and TRU, Bq (Ci) (269) TRU (Plutonium-238, 239, Ameritium-241), Bq 1,4.1011 (Ci) (3,6) Average specific activity of waste dumps Caesium-137, Bq/g 49 Total of caesium-137, strontium-90, plutonium- 113 241, and TRU, Bq/g TRU, Bq/g 1.5 Maximum value of average specific activity for individual dumps Caesium-137, Bq/g 83 Total of caesium-137, strontium-90, plutonium- 189 241, and TRU, Bq/g TRU, Bq/g 2.5

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The waste dumps within the Sector were established in 1987 as a result of decontamination work. The waste in the dumps consists of contaminated soil disposed of in-situ, construction waste from demolished cottages, and tree remains. Metal, concrete and brick are also present in small quantities.

The Sector was surveyed in 1999 by the Scientific and Technical Centre KORO [STC KORO, 1999]. 56 waste dumps were found in the area (19 trenches and 37 mounds). The trenches vary from 11-188m in length, 3-12m in width, and 0.6-2.4m in depth. The mounds vary from 10-245m in length, 4.5-19m in width, and 1.0-3.4m in height.

The geology of the area consists of sand deposits with layers of clay and loamy sand lenses. At the time of the survey, the groundwater table was 0.4-4.4 m below the bottom of the waste and 4 trenches were partially flooded. Currently two mounds are also flooded by a recently formed marsh. Seasonally, during high-levels of groundwater, most of the trenches are flooded. The movement of groundwater is from the south-west to the north-east, with an average groundwater gradient of 0.0015. Groundwater flows towards the Pripyat Inlet at a distance of 2.0 – 2.5 km.

(ii) Physical characteristics of waste According to data obtained during the 1999 survey [STC KORO, 1999] the volume of waste in trenches and mounds in Sector 3.5 was estimated as 54,500 m3 or 87,000 tonnes. The physical characteristics of the waste in the trenches and mounds are summarised in Table 41.

From measurements of gamma dose rate over the surface of the Sector, the surface layer of soil (0-0.05m) was designated as radioactive waste. It was estimated that the total volume of waste in the surface layer is 7,000 m3 (11,200 tonnes). This was calculated assuming that 40% of the Sector area has dose rates of more than 3 µSv/h [STC KORO, 1999].

There are no data available relating to the volumes of waste in the near-surface soil layer.

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(iii) Radiation characteristics of waste The total and specific activities of the waste in the trenches and mounds, according to the revised assessment by STC KORO, are shown in Table 42.

At the time of the 1999 survey, surface gamma-dose rates between 0.5 – 15 µSv/h were measured and the surface beta-contamination varied from 200 -1000 particles/(cm2 min). From the measurements the average specific activity of Cs-137 in the surface soil layer was estimated to be 32 Bq/g.

7DEOH5DGLDWLRQFKDUDFWHULVWLFVRIZDVWHLQWUHQFKHVDQGPRXQGVLQ39/526HFWRU ³6WDQW]L\D

Parameter Value Equivalent dose rate in waste dumps Average equivalent dose rate in the waste dumps, 8.7 µSv/h Maximum equivalent dose rate in the waste 107 dumps, µSv/h Total activity of waste dumps Caesium-137, Bq 3.7 .1012 (Ci) (100) Total of caesium-137, strontium-90, plutonium- 9 .1012 241, and TRU, Bq (Ci) (230) TRU (Plutonium-238, 239, Ameritium-241), Bq 8.3.1010 (Ci) (2) Average specific activity of waste dumps Caesium-137, Bq/g 40 Total of caesium-137, strontium-90, plutonium- 91 241, and TRU, Bq/g TRU, Bq/g 1.4 Maximum value of average specific activity for individual waste dumps Caesium-137, Bq/g 75.2 Total of caesium-137, strontium-90, plutonium- 171 241, and TRU, Bq/g TRU, Bq/g 2.6

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 90 (iv) Waste classification According to the IAEA classification, the waste in Sector 3.5 can be defined as short- lived low and intermediate-level waste (TRU content is less than 400 Bq/g).

 8QVXUYH\HG39/52V  0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV (i) Unsurveyed areas in the Near Zone Data relating to the surveyed PVLRO Sectors were extrapolated in order to estimate the volume and characteristics of the waste concentrated in the unsurveyed areas in the Near Zone [Bugai et al, 2000a].

Data on the volumes and characteristics of waste in the surveyed PVLROs, based on earlier estimations within the framework of the current project [Ovcharov et al, 2000] with correction for radioactive decay to the year 2000, are summarised in Table 43 (see Section 3.6).

From Table 43 it can be seen that the volume of waste disposed in waste dumps per unit area of the surveyed sectors varies from 730 to 1670 m3/hectare, with an average value of 1300 m3/Ha. The waste volume in the soil surface layer varies from 150 to 500 m3/Ha, with an average value of 410 m3/Ha. The waste volume in the subsurface soil layer has been characterised only for Sector 2.1 of Ryzhy Les and Sector 5.3 of Neftebaza, with values of 180 m3/Ha and 1600 m3/Ha respectively.

On average for the surveyed Sectors, the overall volume of waste in both dumps and in surface and subsurface layers is about 2000 m3 per hectare. This is equal to the volume that would be occupied by a 0.2m thick layer of waste evenly distributed over the PVLROs. It is presumed that a layer of approximate thickness of 0.2m was decontaminated following the accident in 1986.

In order to estimate the volumes of waste in the unsurveyed Sectors of PVLROs Ryzhy Les, Stantziya Yanov, Novaya Stroybaza and Kopachi an average value of 2000 m3 of waste per hectare was assumed. In order to estimate the mass of waste in the unsurveyed Sectors an average density of 1.6 tonnes/m3 was assumed.

A different value for the volume of waste per unit area was used for PVLRO Staraya Stroybaza, which is located closer to the Industrial Zone (see Figure 2). Although a systematic survey of the PVLRO has not been performed, in 1996 STC “KORO” performed gamma-ray logging of a small section of the PVLRO where a new road is currently being constructed. For the surveyed region a total waste volume of 2600 m3 per hectare (for waste dumps and in the surface and subsurface soil layers) was estimated. This value of 2600 m3 of waste per hectare was applied to the whole area of the PVLRO in order to estimate the total waste volume.

For Stantziya Semikhody, in order to determine the waste volume, data relating to Neftebaza were extrapolated due to the similarity in the contamination conditions and

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 91 the location of the two PVLROs. The volume of waste of 3700 m3 per hectare for Neftebaza was assumed for Stantziya Semikhody.

7DEOH6XPPDU\RIGDWDRQZDVWHFKDUDFWHULVWLFVUHODWLQJWRVXUYH\HG39/52 6HFWRUV 39/526HFWRU $UHD :DVWH :DVWH $YHUDJHDFWLYLW\RIZDVWHDVDW +D YROXPH YROXPHSHU   P XQLWDUHD &V %HWD $OSKD P KD %TJ %TJ %TJ Ryzhy Les, 2.1 Waste dumps 96 139,000 1450 460 1030 16 Surface soil layer 96 44,000 460 120 268 4 Subsurface soil layer 96 17,000 180 460 1030 16

St Yanov, 3.1+2.3 Waste dumps 16 16,400 1030 42 94 1 Surface soil layer 16 8,000 500 14 31 0.5 Subsurface soil layer N/A

Neftebaza, 5.1+5.2+5.3 Waste dumps 72 120,000 1670 100 224 3.5 (5.1+5.2+5.3) Surface soil layer - 32 14,000 440 50 112 1.8 5.2+5.3 Subsurface soil layer - 5.3 13 20,400 1600 110 246 3.9

Peschannoe Plato Waste dumps 78 57,300 730 47 105 1.6 Surface soil layer 78 33,500 430 21 47 0.7 Subsurface soil layer -

St Yanov, 3.5 Waste dumps 35 54,500 1560 40 90 1.4 Surface soil layer 35 7,000 200 32 72 1.1 Subsurface soil layer N/A

Total for surveyed Sectors Waste dumps 297 387,200 1300 Surface soil layer 257 106500* 410 Subsurface soil layer 109 37400* 340 Total 531100* 2050

Note: * - Sum of volumes of waste in surface and near-surface layers for surveyed PVLROs only where data is available

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 92 The average specific activity of waste in the dumps in the surveyed PVLRO sectors varies from 102 to 103 Bq/g for beta-activity and from 1.4 to 16 Bq/g for alpha activity (for year 2000). It has been assumed that this range in specific activity is also applicable to waste in the unsurveyed PVLRO Sectors. For Novaya Stroybaza, the specific activity of the waste was assumed to correspond to the lowest values in the above ranges due to the fact that the majority of this sector is located at some distance from the ChNPP Unit 4 and in the direction of lower levels of contaminant release.

For the small surveyed section of Staraya Stroybaza the specific activity of the waste was calculated based upon measured values of exposure dose rate [STC KORO, 1996a] (the methodology is described in [Ovcharov et al, 2000]).

Estimating the specific activity of waste in Kopachi was problematic due to the fact that there are no surveyed sectors nearby. The specific activity of the waste in Kopachi was assumed to be of the order of 10-100Bq/g, based on data on contaminated soil in the surrounding area, supplied by the Ukrainian Scientific and Research Institute of Agricultural Radiology [Kashparov et al, 2000].

(ii) PVLROs Pripyat and Chistogalovka For the PVLROs Pripyat and Chistogalovka, SSE Complex Inventory data (Appendix F) was used to estimate the waste characteristics corresponding to the year 1988. There is high uncertainty in these values. For Chistogalovka, the 1988 inventory data was corrected for radioactive decay for the year 2000, assuming that the radionuclide composition of the waste was equal to that of the ChNPP Unit 4 fuel.

 8QVXUYH\HG6HFWRUVRIWKH39/52V5\]K\/HVDQG6WDQW]L\D

According to the IAEA classification, Sectors 2.2-2.6 of Ryzhy Les and 3.2-3.4, 3.6- 3.7 of Stantziya Yanov are not thought to contain long-lived radioactive waste because the sectors are located at a relatively large distance from the most contaminated sectors of the Exclusion Zone.

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# Sectors Area, ha Waste Mass of Average specific Physical composition of waste* volume, waste, activity of waste for (% by volume) m3 tonnes 01/01/2000, Bq/g Total beta Total alpha 1 Ryzhy Les 2.2-2.6, 305 610000 980000 100-1000 1.6 -16 Soil (70%), plant matter (20%), Stantziya Yanov, 3.2-3.4, 3.6-3.7 metal (5%), concrete/bricks (5%) 2 Staraya Stroybaza, 1.1-1.4 186 484000 775000 100-1000 1.6-16 Soil (70%), plant matter (5%), metal (15%), concrete/bricks (10%) 3 Stantziya Semikhody 45 167000 266000 100-1000 1.6-16 Soil(65%), plant matter (20%), metal (10%), concrete/bricks (5%) 4 Novaya Stroybaza, 1.5 120 240000 384000 100 1.6 Soil (70%), plant matter (20%), metal (5%), concrete/bricks (5%) 5 Kopachi 125 250000 400000 10-100 0.1-1 Soil (70%), plant matter (20%), metal (5%), concrete/bricks (5%)

TOTAL   

Note: * - estimations by STC KORO

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 94  39/52³6WDUD\D6WUR\ED]D´ (i) Description of site Staraya Stroybaza (Sectors 1.1-1.4) adjoins the western and south-western boundary of the Chernobyl Industrial Zone (see Figure 2, Figure 31 and Figure 32). Due to its proximity to the Chernobyl Unit 4, high activities of waste are expected in this PVLRO. High contamination of the PVLRO is confirmed by the layout of waste burials in the ChNPP Exclusion Zone outlined by the Civil Defence unit in 1987 (Appendix B).

Facilities linked to work on Shelter-2 will be constructed on the territory of PVLRO Staraya Stroybaza [ISTC, 2000]. Preliminary schemes for the construction work show that Sectors 1.1 and 1.2 of the PVLRO will be affected (see Section 4.4 for details).

The PVLRO has not been surveyed on a systematic basis. However, in 1996 STC “KORO” performed gamma-ray logging of a small section of the PVLRO where a road leading to the Unit Shelter is currently under construction. The road is 40 m wide and 1km long (Figure 33) [STC KORO, 1996a]. The survey gave a rather complicated pattern of soil contamination in the vicinity of the road.

During decontamination work performed at the site following the accident in 1986, contaminated materials at the surface were removed and placed into pits dug in the surrounding area and into depressions in the local relief [STC KORO, 1996a]. The remnants of a cementing solution applied to the surface during the decontamination work is shown in Figure 34.

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(ii) Characteristics of waste Three locations of waste concentration have been identified in the PVLRO: - Surface soil layer (0 – 0.05m). - Subsurface soil layer (0.05 - 1m). - Radioactive waste dumps (more than 1.0 m deep).

The subsurface soil layer (depths of 0.05m to 1m) was seemingly created during the performance of decontamination work, when surface contamination was removed and any residual contamination was covered by a layer of sandy soil. Waste dumps are areas where there is contaminated soil of thickness greater than 1m and which occur at depths of 1 to 3 m. Typically the waste dumps contain contaminated metal, reinforced concrete and wood in addition to contaminated soil. During the construction of the road some alloyed metals, stainless steel and metal construction materials were found.

The results obtained during the survey of the area in the vicinity of the new road are summarised in Table 45. Relatively large volumes of waste were identified in the subsurface soil layer. The total volume of waste per unit area, including waste dumps and contaminated soil layers, was found to be 2,600 m3/Ha, which is slightly higher than the average value for the surveyed PVLRO Sectors.

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Parameter Value Area of survey, ha 4 Waste volume in dumps, m3 3800 Waste volume in subsurface soil layer, m3 5800 Waste volume in surface soil layer, m3 900 Total waste volume, m3 10500 3 Waste volume per unit of area, m /ha  ([SRVXUHGRVHUDWHLQZDVWHGXPSV $YHUDJHH[SRVXUHGRVHUDWHLQGXPSV 6YKRXU 16 0D[LPXPH[SRVXUHGRVHUDWHLQGXPSV 6YKRXU 230 $YHUDJHVSHFLILFDFWLYLW\RIZDVWHLQGXPSV Caesium-137, Bq/g 74 Sum of Cs-137, Sr-90, Pu-241 and TRU, Bq/g 170 TRU, Bq/g 2 0D[LPXPYDOXHVRIDYHUDJHVSHFLILFDFWLYLW\IRULQGLYLGXDOZDVWHGXPSV Caesium-137, Bq/g 1060 Sum of Cs-137, Sr-90, Pu-241 and TRU, Bq/g 2500 TRU, Bq/g 30

The volumes and characteristics of the waste in PVLRO “Staraya Stroybaza”, as a whole, are shown in Table 44.

(iii) Waste classification Taking into account the fact that localised regions of long-lived waste (according to the IAEA classification) have been identified in Sector 2.1 of Ryzhy Les and the location of Staraya Stroybaza between Sector 2.1 and the ChNPP Industrial Zone, localised regions of long-lived wastes, according to the IAEA classification, are expected for Staraya Stroybaza. Using values for Ryzhy Les, it was assumed that PVLRO Staraya Stroybaza contains 0.45% of long-lived wastes (by volume). More accurate estimates of the volume of long-lived waste cannot be made without a detailed survey of the site.

 39/52³6WDQW]L\D6HPLNKRG\´ There is no data relating to PVLRO Stantziya Semikhody contained within the State Enterprise “Complex” Exclusion Zone Inventory Report [IGS, 1999]. However, SSE “Complex” experts did identify this area as a separate PVLRO Sector. It is expected that some waste dumps are located within the PVLRO, as indicated by the 1987 schematic of dumps (see Appendix B). The layout of the PVLRO is shown in Figure 35.

The characteristics of waste in PVLRO Stantziya Semikhody are expected to be similar to those for PVLRO Neftebaza, due to the similar contamination conditions and close location. Estimated volumes and characteristics of waste at Stantziya Semikhody are shown in Table 44.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 98 The waste within the PVLRO is expected to be short-lived low and intermediate level waste (according to the IAEA classification).

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The layout of “Novaya Stroybaza” is shown in Figure 36. This PVLRO is located at some distance from the surveyed PVLRO sectors. Estimated waste volumes and characteristics are shown in Table 44. The physical composition of the waste was assumed to be similar to that of Stantziya Yanov.

The specific activity of the waste in the PVLRO was assumed to correspond to the lowest value in the range determined for the surveyed PVLROs, due to the fact that the majority of this sector is located at some distance from the ChNPP Unit 4 and in the direction of lower levels of contaminant release.

The presence of long-lived waste (according to IAEA classification) in the PVLRO is not expected.

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 39/52³.RSDFKL´ PVLRO “Kopachi” contains construction waste from the demolition of Kopachi village. This PVLRO is considerably further from the ChNPP (4.5 km) compared to the other PVLROs (see Figure 36).

Estimated volumes and characteristics of the waste in the PVLRO are shown in Table 44. The physical composition of the waste was estimated by analogy with PVLRO Stantziya Yanov, which also contains waste from demolished villages.

From the level of contamination of the surrounding area [Kashparov et al, 2000] the specific activity of waste in Kopachi was estimated to be low, 10-100 Bq/g (Table 44). According to Regulations for Solid Radioactive Waste Management [SPORO, 1985] the materials within Kopachi are on the borderline between the radwaste and free release levels. The presence of long-lived waste (according to the IAEA classification) is not expected.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 100  39/52³3ULS\DW´ The data relating to this PVLRO are inadequate and those which exist are contradictory.

According to State Enterprise “Complex” inventory data (Appendix F) and V. M. Antropov reports, PVLRO “Pripyat” is located adjacent to the northern, north-eastern, and western boundaries of Pripyat town. According to the inventory data the area of the PVLRO is 70 Ha. Wastes contained within trenches at the PVLRO consist of contaminated motor cars, motorcycles, other machinery, wood, and construction waste from demolished villages etc. According to the State Enterprise “Complex” inventory data, the PVLRO contains 16,000 m3 of radioactive waste (11000 tonnes), with a total activity of 2.6x1013 Bq (1990). According to these data the volume of waste per unit area for the PVLRO (230 m3/ha) is 10 times lower than the value for the surveyed sectors.

Experts from the Scientific Technical Centre “KORO” consider that PVLRO “Pripyat” in fact does not exist, with there only being some disorganised dumps of domestic waste in the vicinity of Pripyat town. PVLRO Pripyat is not marked on the IGS schemes of the ChNPP Near Zone. In the State Enterprise “Complex” layout, provided within the framework of the current project [IGS, 1999], the PVLRO is marked but with an area that does not agree with the value of 70 Ha contained in the inventory report. This PVLRO is absent from the schemes showing the layout of the waste dumps based on Scientific Industrial Association data (1987) (Appendix B) and is also absent from the Research and Design Institute of Industrial Technologies scheme (1992) (Appendix G).

It is not expected that there is any long-lived waste (according to IAEA classification) within the area.

 39/52³&KLVWRJDORYND´ PVLRO Chistogalovka is located 0.7km from the village of Chistogalovka, at a relatively large distance from ChNPP (approximately 5 km) compared to the other PVLROs (see Figure 36). The PVLRO is situated in a clay quarry and has an area of 6 Ha. The PVLRO was established in 1986 – 1987, and until 1990 the site had the status of a disposal facility. However, from 1990 the site was re-categorised as a PVLRO (i.e. temporary storage facility).

The waste dump is a near surface facility with an approximately 3-4m thick layer of clay lining the base. After wastes were loaded into the dump in 1987, the dump was filled with soil and covered with a 1m thick layer of clay. Reliable data relating to the characteristics of the waste at the PVLRO are not available.

According to the State Enterprise “Complex” inventory data (see Appendix F) and the 1990 documentation [SSE Complex, 1990c], there is 160,000 m3 of waste at the PVLRO (150,000 tonnes) with an activity of 3.7x1012 Bq (1988). The layout of the PVLRO is shown in Figure 37. According to the data available, waste within the PVLRO consists of construction materials from the demolition of buildings at Stantziya Yanov, contaminated soil, wood, and contaminated working clothes. The groundwater table is situated at a depth of 14-17 m.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 101 According to Scientific and Industrial Association “Pripyat” documents, owned by IGS, in 1989 – 1990 some of the waste (about 9,500 m3) within the PVLRO was retrieved and re-disposed at the PZRO Buryakovka. At this time the region of the dump that was exposed was surveyed, with exposure dose rates of 0.4 – 1.6 mR/hour being measured.

7KHVSHFLILFDFWLYLW\RIWKHZDVWHFRUUHVSRQGLQJWRWKH\HDUZDVHVWLPDWHGZLWKLQ WKHIUDPHZRUNRIWKHFXUUHQWSURMHFW VHH6HFWLRQ DVa%TJ Table 46). This is below the lower limit defining radioactive waste specified in SPORO-85. Thus according to the SSE Complex data, the materials disposed in Chistogalovka are not radioactive wastes according to their activity in 2000, in which case the site should not be classified as a PVLRO (Radwaste Temporary Storage Site).

However, the SSE Complex data are not reliable and a survey of the site is necessary in order to determine whether indeed the site no longer contains radioactive waste. It is not expected that any long-lived waste (according to the IAEA classification) is contained within the PVLRO.

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Radio- Contribu- Activity, GBq Specific Activity, GBq Specific activity, nuclide tion to activity, For activity, Bq/g For Bq/g % for 31.12.88 31.12.88 for 01.01.00 For 31.12.88 01.01.00 90Sr 17.71 6.55E+02 4.37E+00 5.02E+02 3.35E+00 134Cs 5.69 2.10E+02 1.40E+00 5.18E+00 3.46E-02 137Cs 20.73 7.67E+02 5.11E+00 5.96E+02 3.97E+00 144Ce 29.01 1.07E+03 7.16E+00 5.98E-02 3.99E-04 154Eu 0.92 3.40E+01 2.26E-01 1.43E+01 9.52E-02 238Pu 0.10 3.88E+00 2.59E-02 3.55E+00 2.37E-02 239Pu 0.08 2.91E+00 1.94E-02 2.91E+00 1.94E-02 240Pu 0.13 4.78E+00 3.18E-02 4.77E+00 3.18E-02 241Pu 13.29 4.92E+02 3.28E+00 2.89E+02 1.93E+00 241Am 0.05 1.95E+00 1.30E-02 1.92E+00 1.28E-02

244Cm 0.03 1.16E+00 7.71E-03 7.59E-01 5.06E-03 Total 3.25E+03 2.16E+01 1.4E+03 9.5E+00 beta Total 1.4E+07 9.3E-02 alpha

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 'HVFULSWLRQRI6LWH Soils within the Exclusion Zone (radius of 30km) were contaminated during the Unit 4 accident. The contamination was largely associated with the fall-out of finely dispersed nuclear fuel particles [Kashparov et al, 2000]. The most contaminated region is that in immediate proximity to Unit 4, the Shelter Local Zone, which is within the Chernobyl Industrial Zone (see Section 3.1). Beyond the Shelter Local Zone is the ‘Near Accident Zone’ (radius 3-5km).

Investigations of contaminated soil within the Exclusion Zone have shown that the contamination is largely concentrated in the surface 30cm of soil.

 0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV The contamination of soils within the Exclusion Zone by transuranic elements (TRU) was investigated by performing Sr-90 mapping in 1998. A grid of about 13,000 sampling points, spaced at intervals of 1-2km, was established over the 30km Exclusion Zone. In areas of high gradients in soil contamination a finer grid, with sampling points spaced at 100-500 m intervals, was used. At each sampling point the Sr-90 contamination was measured to a depth of 30cm. However, in regions of sandy soils, where increased vertical migration of Sr-90 is expected, the depth of sampling was increased to 1m. The vertical distribution of Sr-90 in the soil was determined using a layer-sampling method. The sampling methods are described in detail in Appendix A.

The results from the field investigation were interpreted using a software package ‘Surfer’. This package applied a filter to the measurements of Sr-90 contamination in order to correct for the random error introduced by the sampling and measurement process (for details see Appendix A). From the results a Sr-90 contamination density map was developed based on the GPS (global positioning system) co-ordinate system.

Correlation ratios between the Sr-90 and TRU specific activities were determined experimentally for contaminated soil in the near-field zone (see Appendix A). These were used to determine the TRU content of the contaminated surface soil layer, corresponding to the year 2000. A map was developed showing the activity of TRU alpha-emitters (238Pu, 239Pu, 240Pu, 241Am, and 244Cm) in the surface 10cm-depth of soil, over the Exclusion Zone, for the year 2000 (Figure 38).

 :DVWHFKDUDFWHULVWLFV The investigations of contaminated soil across the Exclusion Zone showed that, at the majority of sampling points, more than 95% of the 90Sr activity is concentrated in the surface 30-cm depth of soil. At less than 0.1% of the sampling points was a significant proportion (more than 20%) of 90Sr found to have migrated to depths greater than 30 cm.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 104 Four zones were identified as containing soils with specific activities of alpha- emitting radionuclides (238Pu, 239Pu, 240Pu, 241Am, 244Cm) of greater than 0.37 Bq/g 13 (Figure 39). The largest accumulation of activity (2.49x 10 Bq) was identified in Zone 1, which has an area of 147.9 km2 and a TRU concentration of 0.37–3.7 Bq/g. In Zones 2-4, higher TRU concentrations in the soil (in the range 3.7-37 Bq/g) were identified: Zone 2 has a total area of 3.7 km2 and a peak concentration of TRU of 20 2 Bq/g; Zone 3 has a total area of 3.6 km and a peak concentration of TRU of 9Bq/g; 2 and Zone 4 has a total area of 0.8 km and a peak concentration of TRU of 5Bq/g (see Table 47).

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The contaminated soil is classified as short-lived low and intermediate level waste, according to the IAEA classification.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 107  2WKHUVRXUFHVRIZDVWHZLWKLQWKH([FOXVLRQ=RQH Other sources of largely uncharacterised waste within the Exclusion Zone include:

- Approximately 100 ‘unauthorised’ disposal sites containing radioactive waste - Sites Rassoha 1 and Rassoha 2 containing contaminated machinery

 8QDXWKRULVHGGLVSRVDOVLWHV There are over 100 'unauthorised' sites containing radioactive waste, which have been identified within the Exclusion Zone. The majority of these sites are located within the 10-km area around the ChNPP. For the majority of ‘unauthorised’ sites that have been identified there is no information available other than their location, although in some cases attempts have been made to characterise the waste and to estimate γ/β activities and the overall mass of the waste. The waste within the sites includes:

- contaminated soil; - construction waste; - metals; - contaminated machinery.

Some of the wastes are currently being retrieved and re-disposed of at PZRO Buryakovka. In 1999 SSE Complex retrieved some 37,000 m3 of these wastes, which comprised contaminated soil, construction waste from destroyed buildings and metal.

 5DVVRKDDQG Approximately 30 helicopters and 3000 contaminated vehicles are stored at Rassoha 1 and Rassoha 2. Other contaminated machinery includes contaminated ships, which are moored on the banks of river Pripyat. Characterisation of the contamination levels of this machinery is currently ongoing. It is unlikely that any of these wastes will be characterised as long-lived according to the IAEA classification.

 $QDO\VLVRIUHOLDELOLW\RIGDWDIRU39/52VFRQWDPLQDWHGVRLOPDFKLQHU\DQG XQDXWKRULVHGGLVSRVDOVLWHV 1. The majority of the PVLRO sectors have not yet been surveyed, with no reliable data for these being available. In one case (PVLRO Pripyat) the very existence of the dump is questionable.

2. There is little data relating to the volumes and activities of vegetation growing on the PVLROs.

3. There is only data relating to the volumes and characteristics of contamination in the near surface soil layer for PVLROs Neftebaza Sector 5.3, Ryzhy Les Sector 2.1 and Peschannoe Plato Sector 6.0.

4. When estimating the volume of waste in the surface layer a constant thickness for soil contamination of 5cm was assumed.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 108 5. The measurements made during gamma-ray logging only characterise a cylinder of soil with a 50cm radius and a height of 10cm. Measurements from such a small volume are unlikely to be representative of the waste within the waste dumps as a whole.

6. An accurate assessment of the total volume of long-lived waste in Sector 2.1 of Ryzhy Les is not possible due to a lack of any data relating to the statistical distribution of gamma-probing results for the individual waste dumps (with only the average and maximum dose rates being presented in [NIPIPromtechnologii, 1992] for each trench).

7. There is no information on the contamination and quantity of vegetation present at the majority of contaminated sites. In the case of Ryzhy Les it is known that contamination of trees exceeds free release levels.

8. While it is known that a surface waters seasonally or permanently flood some PVLROs and a significant proportion of contaminated soils, there is no data on contamination levels present in the resulting water bodies.

9. Sampling of contaminated soil outside the dumps was performed using a grid size of 1-2km. With such a large sampling interval localised regions of high TRU concentrations may not be identified. Large sampling errors are likely to be associated with the results.

10. Except where there are sandy soils sampling has only been performed to a depth of 30cm. There is little data on the soil contamination below this depth. However, since contamination of the soils was the result of deposition, it is likely that the highest concentrations are near the surface.

11. At present there is no reliable data on the contamination or quantity of waste from Rassoha or other sites where such machinery is being stored.

 ,GHQWLILFDWLRQRIIXUWKHUDFWLYLWLHVWRLPSURYHGDWDTXDOLW\ In order to obtain a more certain value for the waste inventory a survey of all uncharacterised sites, which are likely to contain radionuclide wastes, is required.

Especial attention should be paid to three types of locations: 1. PVLROs, containing relatively high level of activity, such as PVLROs Staraya Stroybaza and Ryzhy Les 2. PVLROs and contaminated soil, which are seasonally or permanently flooded by surface waters 3. Contaminated machinery and other wastes, which are exposed to potential theft.

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There are four principle sources of contamination within the Exclusion Zone, which have been considered within this project:

1. Industrial Zone (Promploshadka) 2. PZROs (Engineered Disposal Sites) 3. PVLROs (Temporary Storage Sites) 4. Contaminated soil.

The waste characteristics of the individual dumps within the Exclusion Zone described in Section 3 are summarised in Table 48. The hydrogeological conditions in the vicinity of the waste dumps are shown in Table 49 [see Appendix H].

In addition to the above sources of contamination there are unauthorised disposal sites throughout the Exclusion Zone for which the waste is largely uncharacterised.

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   V\VWHP %TNJ %T ,QGXVWULDO=RQH 3URPSODVKDGND Shelter Local 12,900 8E5 1.84E13 Concrete, sand SL-LILW Contamination of No Zone Sector 1 surface man-made soil layers Shelter Local 9,850 2.1E7 3.74E14 Concrete, sand 92% SL- Contamination of No Zone Sector 2 LILW surface man-made 8% LL-LILW soil layers Shelter Local 36,500 4.5E5 2.93E13 Concrete, sand, clay SL-LILW Contamination of No Zone Sector 3 surface man-made soil layers Shelter Local 75,800 3.1E7 4.16E15 Concrete, sand, 98.5% SL- Contamination of No Zone Sector 4 rubble LILW surface man-made 1.5% LL- soil layers LILW Shelter Local 126,435 4.2E6 9.30E14 Concrete, sand, 97% SL- Contamination of No Zone Sector 5 rubble LILW surface man-made 3% LL-LILW soil layers Shelter Local 26,805 8.5E7 4.04E15 Concrete, sand, SL-LILW Contamination of No Zone Sector 6 rubble, construction surface man-made waste soil layers Industrial Zone 150,000 Unknown Unknown Concrete, sand, ~99% SL- Contamination of No outside Shelter rubble, gravel, some LILW surface man-made Local Zone metal etc 0.5-1% LL- soil layers LILW 3=52V

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   V\VWHP %TNJ %T Podlesny 3,960 1.3E8 1.0E15 Graphite, metal, LL-LILW Grouted waste, No reactor core fractured concrete construction compartments materials, construction wastes 4,800 Unknown Unknown Concrete grout SL-LILW Concrete grout on top No of waste, covered by sand/gravel mix Kompleksny 26,200 1.78E6 7.5E13 Soil, ChNPP Unit 4 SL-LILW ~50% in metal No debris, construction containers in concrete waste and ChNPP compartments, ~50% site wastes loose at voids at ends of compartments. Waste covered with clay and soil. Surface depressions due to subsidence Buryakovka 590,000 1.8E5 1.5E14 Soil, metal, concrete, >99% SL- Waste in engineered No (Engineered (1998) (1998) construction waste LILW trenches trenches) 0.026% LL- LILW Buryakovka 4190 Unknown Unknown Contaminated SL-LILW Open-air store No (Contaminated machinery machinery store)

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   V\VWHP %TNJ %T 39/52V Ryzhy Les 139,000 1.0E6 2.3E14 Mainly soil and >99% SL- Trenches, mounds, 10yr old Sector 2.1 (dumps) (dumps) (dumps) vegetation. Some LILW surface and near- pine forest, 61,000 construction and 0.45% LL- surface contaminated birch and (top soil) domestic waste from LILW soil layers. bushes, demolished seasonal buildings. wetlands Stantziya Yanov 16,400 9.5E4 2.5E12 Soil, plant matter, SL-LILW Trenches, mounds, 8-10 yr old Sectors 2.3 and (dumps) (dumps) (dumps) metal, concrete, surface and near- pine trees 3.1 13,400 brick. surface contaminated (top soil) soil layers. Stantziya Yanov 54,500 9.1E4 9E12 Soil, construction SL-LILW Trenches, mounds, Pine trees. Sector 3.5 (dumps) (dumps) (dumps) waste, tree remains. surface and near- Seasonal 18,900 Some metal, surface contaminated wetlands. (top soil) concrete and brick. soil layers. Ryzhy Les 610,000 1E5-1E6 1E14- Soil, plant matter, SL-LILW Trenches, mounds, Pine trees Sectors 2.2, 2.4- 1E15 metal, concrete, surface and near- 2.6 brick. surface contaminated Stantziya Yanov soil layers. Sectors 3.2-3.4, 3.6-3.7 Neftebaza 120,000 2.3E5 4.4E13 Soil, plant matter, SL-LILW Trenches, mounds, Wetlands. (dumps) (dumps) (dumps ) metal, concrete, surface and near- 113,000 brick. surface contaminated (top soil) soil layers.

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   V\VWHP %TNJ %T Peschannoe 57,300 1.1E5 1.0E13 Soil, rubble, SL-LILW Trenches, mounds, Sparsely Plato (dumps) (dumps) (dumps) concrete. surface and near- vegetated 33,500 surface contaminated with grass (top soil) soil layers. and shrubs. Few pine trees/bushe s. Staraya 484,000 1E5-1E6 1E14- Soil, metal, concrete, >99% SL- Trenches, mounds, Bushes / Stroybaza 1E15 wood. LILW surface and near- some trees ~0.45 LL- surface contaminated LILW soil layers. Novaya 240,000 1E5 3.8E13 Soil, plant matter, SL-LILW Trenches, mounds, Bushes / Stroybaza metal, concrete, surface and near- some trees brick. surface contaminated soil layers. Stantziya 167,000 1E5-1E6 1E13- Soil, plant matter, SL-LILW Trenches, mounds, Unknown Semikhody 1E14 metal, concrete, surface and near- brick. surface contaminated soil layers. Kopachi 250,000 1E4-1E5 1E12- Construction waste SL-LILW Trenches, mounds. Bushes / 1E13 from demolition of some trees village. Pripyat 16,000* 2.4E6* 2.6E13* Contaminated SL-LILW Trenches, mounds. Unknown (1990) (1990) vehicles, machinery, wood, and construction waste

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   V\VWHP %TNJ %T Chistogalovka 160,000 1E4 1.5E12 Construction SL-LILW Waste in clay quarry. Unknown materials from Dump filled and demolition of covered with clay. buildings, soil, wood and contaminated working clothes. &RQWDPLQDWHGVRLO I 17,494,0 5.88E4 1.54E15 Contaminated soil SL-LILW Contaminated surface Grass 00 soil layer /bushes /some trees II 371,500 6.87E5 3.83E14 Contaminated soil SL-LILW Contaminated surface Grass soil layer /bushes /some trees III 362,000 3.62E5 1.97E14 Contaminated soil SL-LILW Contaminated surface Grass soil layer /bushes /some trees IV 82,750 2.38E5 2.96E13 Contaminated soil SL-LILW Contaminated surface Grass soil layer /bushes /some trees

Note * Data presented for PVLRO Pripyat is according to SSE Complex inventory data. However, this data are unreliable and contradicts other sources of data on this PVLRO. According to STC KORO experts this dump simply contains non-radioactive domestic waste and is not a PVLRO.

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6LWH &RPSRVLWLRQRI *URXQGVXUIDFH $YHUDJHGHSWK :DVWHLV :DVWHLV *URXQGZDWHU &RQGXFWLYLW\ *URXQGZDWHUIORZ 'LVWDQFHWR VDWXUDWHGDQG DFWXDOKHLJKW IURPWKHJURXQG FRQVWDQWO\RU FRQVWDQWO\RU IORZDYHUDJH PGD\ GLVFKDUJHDUHD GLVFKDUJHDUHD XQVDWXUDWHG]RQHV DERYHVHDOHYHO  VXUIDFHWRWKH SHULRGLFDOO\ SHULRGLFDOO\ JUDGLHQW VXUIDFHSRRO P P JURXQGZDWHU IORRGHGE\ IORRGHGE\ PP OHYHOP JURXQGZDWHU VXUIDFHZDWHU \HVRUQR \HVRUQR ChNPP Man-made layers 115 4 No No 0.001 1-10 Azbuchin Lake 1500 Industrial Zone (sand, crushed stone, concrete), sand, loamy sand 3=52 Podlesny Sand, loamy sand 115 8 No No 0.002 0.1-10 The Pripyat Inlet 500 Kompleksny Sand, loamy sand 116 5 Yes No 0.0001 1-10 Cooling pond 250 Buryakovka Sand, loamy sand, 140 16 No No 0.0005 0.1-10 The river Uzh 2000 clays (feeder) 39/52 Stantziya Sand, loamy sand 113 3 Yes Seasonal surface 0.002 1-10 The Pripyat Inlet 1200 Yanov flooding for W & SW peripheral areas. Stroybaza Sand, loamy sand 114 3 No No 0.001 1-10 The Pripyat Inlet 1000 Neftebaza Sand, loamy sand 107 (flood plain), 1 (flood plain), Yes (flood Yes (flood plain),0.004 (flood 0.1-10 The Pripyat Inlet, 0 115 (terrace) 6 (terrace) plain), no (terrace) plain), the Pripyat river No (terrace) 0.008 (terrace) Peschannoe River deposits, 113 7 No No 0.002 5-20 The Pripyat river 500 Plato sand, loamy sand Pripyat Sand, loamy sand 113 6 No No 0.002 1-10 The Pripyat Inlet 1300 Kopachi Sand, loamy sand 112 2 Unknown No 0.001 1-10 Stream Borschi, 0 Stream Rodvino Chistogalovka Sand, loamy sand, 140 7 - 14 No No 0.001 0.1-10 Stream Rodvino 2000 clays

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 ,$($6DIHW\*XLGHOLQHVIRU1HDU6XUIDFH'LVSRVDO According to IAEA Safety Guidelines, near surface disposal is an option for disposing of low and intermediate level radioactive waste containing short-lived radionuclides and acceptably low concentrations of long-lived radionuclides [IAEA, 1994b]. The IAEA definition of short-lived low and intermediate level waste, which is suitable for near-surface disposal, is:

- <4000 Bq/g long lived α in individual packages, - <400 Bq/g average long lived α, and - thermal power below about 2kW/m3.

The ICRP has recommended that the appropriate risk constraint for members of the public for a near surface repository is 0.3 mSv/y [IAEA, 1999]. For the human intrusion pathway the ICRP recommended dose constraint is 10 to 100 mSv/y [ICRP, 1998].

IAEA Guidelines in relation to near surface disposal include the following [IAEA, 1994b & 1999]:

1. When properly implemented a near surface disposal system should provide adequate isolation of radionuclides from the biosphere for periods of time necessary to allow their decay to safe levels. 2. The geological setting at the site should contribute to the isolation of waste and the limitation of releases of radionuclides to the biosphere. 3. Surface processes such as flooding of the disposal site, landsliding or erosion should not occur with such frequency or intensity that they could affect the ability of the disposal system to meet safety requirements. 4. The site shall be located such that activities by present or future generations at or near the site will not be likely to affect the isolation capability of the disposal system. 5. Near surface disposal facilities may include engineered barriers which, together with the emplacement medium and its surroundings, isolate the waste from humans and the environment.

 &RPSDULVRQRIZDVWHGLVSRVDOZLWKLQ([FOXVLRQ=RQHZLWK,$($ 5HFRPPHQGDWLRQV The following dumps have been identified as possibly containing long-lived waste, the near-surface disposal of which is not in compliance with IAEA recommendations:

- Small quantities of long-lived waste have been identified within the surface soil layers in the Industrial Zone. The long-lived waste is largely concentrated in the thin accident related layer within the Shelter Local Zone. Localised regions of long-lived waste are also expected outside the Shelter Local Zone, mainly located in the soil layer close to the pre-accident surface level.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 117 - For PZRO Buryakovka, according to the current waste acceptance criteria, waste of average transuranic activity of <2200 Bq/g can be disposed of at Buryakovka. Thus waste that is classified as long-lived according to the IAEA definition can currently be disposed at Buryakovka, in conflict with IAEA requirements. Assessment of the actual content of Buryakovka (see Section 3.4) suggests that IAEA long-lived waste (i.e. long-lived alpha >400 Bq/g) is approximately 0.026% out of the total volume of 590,000 m3. - The waste stored within PZRO Podlesny has been estimated to exceed the IAEA activity limits for short-lived waste. - In addition there is evidence of the presence of localised regions of long-lived waste in Sector 2.1 of PVLRO Ryzhy Les, with localised regions of long-lived waste also being expected in PVLRO Staraya Stroybaza.

For the following dumps the waste is either continuously or seasonally flooded by surface water, which does not comply with IAEA requirements:

- 50% of Sector 5.1 of PVLRO Neftebaza is situated on the Pripyat floodplain and the waste is either continuously or seasonally flooded. - Contaminated soil situated on the Pripyat floodplain (including soil both within and outside of PVLRO Neftebaza) is either continuously or seasonally flooded. - Significant quantities of soils contaminated above the free release threshold (~50%) are situated on wetland areas which are periodically flooded by surface water. From Figure 40 it can be seen that the contaminated wetland areas are largely situated on the left bank of the Pripyat River. - The West and South-West peripheral areas of Sector 2.1 of Ryzhy Les are located on a seasonal wetland area (Luchkovo Boloto), which is periodically flooded by surface water. - The West and South-West peripheral areas of Sector 3.5 of Stantziya Yanov are located on a seasonal wetland area (Luchkovo Boloto), which is periodically flooded by surface water.

For PZRO Kompleksny the waste within the facility is saturated, with the groundwater level varying between 0.5 and 0.7m above the bottom of the waste. In addition there is localised subsidence with depressions visible on the surface. This does not comply with IAEA requirements that surface processes such as flooding, landsliding and erosion should not occur with such frequency or intensity that they could affect the ability of the disposal system to meet safety requirements.

For the PVLROs, unauthorised dumps and regions of contaminated soil within the Exclusion Zone, the waste is not adequately isolated from the biosphere, which is not in compliance with IAEA guidelines.

Waste disposal within the Exclusion Zone does not currently comply with the international guidelines for near surface disposal, as detailed above. However, these guidelines are largely applied in relation to planned near surface repositories. A risk assessment is required to understand whether the conditions comply with the Ukrainian regulations on waste disposal. The entire removal of all waste from within the Exclusion Zone is not feasible due to the large extent of the contamination and the huge resources that would be required for the safe management of the generated waste

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 118 streams. Thus the waste dumps need to be prioritised according to the risk posed to the public and the environment, to allow an effective use of resources.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 119  4XDOLWDWLYHDVVHVVPHQWRIWKHFRPSDUDWLYHULVNVWRWKHSXEOLFDULVLQJIURPWKH GXPSV  ([SRVXUHSDWKZD\V In order to assess the risks to the public arising from the waste dumps, preliminary estimates of doses arising from the sources of contamination within the Exclusion Zone for the most significant pathways have been made. Doses both within and outside the Exclusion Zone have been estimated and separate assessments have been made for current and forecasted doses.

For exposure beyond the 30-km Exclusion Zone the three pathways that are judged to be of most significance are: - Ground and surface waters - Atmospheric dispersion including forest fires - Ingestion of migrating contaminated birds and animals

For exposure within the Exclusion Zone the following exposure pathways have been assessed: - Direct exposure - Atmospheric dispersion including forest fires - Human Intrusion - Ground and surface waters - Ingestion of contaminated birds, animals and plants

 ([SRVXUHRXWVLGH([FOXVLRQ=RQH (i) Exposure through ground and surface waters The primary route of exposure outside the Exclusion Zone via ground and surface waters is the ingestion of water and fish from the Pripyat and the Dniepr. Berkovski et al, 1996, identify the critical group as professional fishermen in the Kiev Reservoir with doses not exceeding 0.17 mSv/yr in 1993. However, most of the Cs-137 activity in the Dniepr originates from the Pripyat floodplain upstream of the Exclusion Zone. Taking into account the current estimated contribution to activity in the Pripyat from the Exclusion Zone (of 0.3GBq/y [Dzepo, 1996]), a dose of 0.003 µSv/y to the critical group for sources within the Zone has been calculated within the current project.

In 100 years, the contribution to activity in the Pripyat from the Exclusion Zone is predicted to increase nearly 500 times [Dzepo, 1996] with the resulting dose to fishermen being estimated as 1 µSv/y.

The contribution to the dose off-site via this exposure pathway, for the individual waste dumps, is judged to depend on the following factors: - Whether the dump is flooded and the distance between the groundwater table and the level of the waste. - The composition of the saturated and unsaturated zones. - The groundwater flow gradient - The proximity of the dump to the groundwater discharge area (surface water body). - The activity of waste contained within the dump.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 120 - The state of containment of the waste.

The characteristics of the individual waste dumps within the Exclusion Zone are shown in Table 48 and the hydrological conditions in the vicinities of the dumps are shown in Table 49.

For PZRO Podlesny, groundwater monitoring within the site by RADEK has shown that, currently, groundwater adjacent to the PZRO is not contaminated. However, the boreholes that are used to monitor the contamination are located several tens of metres from the PZRO and may miss the contamination. Nevertheless, the PZRO is separated from the groundwater by an unsaturated zone (~5m thick) containing clay layers and is judged to pose little current risk of groundwater contamination.

The waste in PZRO Kompleksny is currently saturated, with the groundwater level varying between 0.5 and 0.7m above the bottom of the waste. No groundwater contamination has been detected in wells adjacent to the facility. However, the monitoring wells are badly positioned and may miss the contamination. The disappearance of the Cooling Pond in the future will result in the groundwater gradient adjacent to this facility increasing, but may also cause the groundwater table to drop below the bottom of the waste. This will decrease the loss of activity into the groundwater, but contaminant transport modelling is required to predict the impact of the disappearance of the Cooling Pond on the risk of exposure to the public posed by the PZRO.

PZRO Buryakovka is judged to pose little current risk of groundwater contamination because the waste is located in the unsaturated zone and precipitation is diverted by the relatively efficient capping and a drainage system.

Of the PVLROs, Neftebaza, 20-25% of which is located in the Pripyat floodplain, is likely to contribute most significantly to the off-site dose from this exposure pathway. Leaching rates into the Pripyat Inlet and the subsequent leaching into the Pripyat River from Neftebaza have been estimated within the current project, using data relating to the radionuclide inventory from Kulachinsky et al. [1996]. The resultant increase in concentration of Sr-90 in the Pripyat Inlet is conservatively estimated as 1.6 Bq/l, and in the River Pripyat as 7E-05 Bq/l. However, the existing Sr-90 concentrations in the Pripyat Inlet are 60-80 Bq/l, largely from the leaching of bottom sediments. Thus, the contribution to activity in the Pripyat Inlet from leaching from Neftebaza is insignificant in comparison to leaching of the bottom sediments.

An assessment of the risks from radionuclide migration to groundwater in the Exclusion Zone [Bugai et al, 1996] found that radionuclide transport off-site via the ground/surface water pathway was dominated by wash-out of contaminated soils by surface water during spring snowmelt and rains. Thus contamination within the dumps has relatively small impact.

(ii) Exposure from atmospheric dispersion The principal exposure pathways in this category include doses resulting from the re- suspension and atmospheric dispersion of radionuclides. Exposure can be the result of:

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 121 - Strong winds lifting contaminated dust; - Fires releasing activity contained in trees or topsoil; - Dust emissions generated during the movement of personnel and vehicles on site; - Dust emissions generated as a result of activities impacting directly on the waste.

The maximum measured concentration of activity in the atmosphere from forest fires 20 Bq/m3 in 1992 [Marchenko & Doroshenko, 1997]. Adjusting concentrations for dispersion over 30-km, using the Gaussian plume model, resulting doses of ~0.02 µSv/y were estimated within the current project. In ~100 years. doses due to forest fires are judged unlikely to increase, because the activity concentration in vegetation is not expected to increase over this time period.

The contribution to the dose off-site via this exposure pathway, for the individual waste dumps, is judged to depend on the following factors:

- Forest/vegetation cover of the dump - Whether the surface of the dump is dry - Whether waste is exposed at the surface - The activity contained within the dump - Frequency of vehicle movement over the dump - Performance of any activities directly impacting on waste.

For the Industrial Zone, radioactive dust emissions into the air generated during the movement of personnel and transport vehicles on the site, is a significant exposure pathway leading to contamination of the environment and doses to the public off-site. In addition, the direct transfer of contaminated soils from the Industrial Zone off-site via the movement of vehicles is also judged to be significant based on information provided by the Administration of the Chernobyl Exclusion Zone.

In its current state, any activities directly impacting on the contaminated soil within the Industrial Zone pose a significant risk of exposure due to the generation of dust. This is likely to pose a significant hazard in the future due to the planned operations associated with the renovation of the Unit Shelter, construction of waste management facilities and the decommissioning of Chernobyl NPP.

At present the PZROs are unlikely to contribute significantly to the dose via atmospheric dispersion, due to the fact that the waste is partially containerised and stored within vaults or engineered trenches. However, in the future, there is a risk of erosion and the dispersion of contaminated dust. This is particularly the case for PZRO Compleskny where there is localised subsidence and there are currently depressions visible on the surface.

Of the PVLROs, Ryzhy Les and Stantziya Yanov are likely to contribute most significantly to the dose via this exposure pathway, since in both cases the dumps are forested. The radionuclide accumulation in vegetation on Trench No 22 at Ryzhy Les is given in [Kashparov, 1999]. Based on these data, it was conservatively estimated within the current project, using Gaussian plume dispersion, that the individual dose at 30 km due to a fire on the Trench would be ~0.001 µSv.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 122 Areas of contaminated soil within the Exclusion Zone are likely to contribute significantly to the off-site dose from both fires and wind blown dust.

(iii) Exposure from ingestion of contaminated animals and birds Outside the Exclusion Zone, the ingestion of contaminated foodstuffs from the Exclusion Zone is likely to be on an occasional basis and limited to contaminated birds and animals. Concentrations of activity in ducks that nest on the shores of the Cooling Pond have been measured up to 37Bq/g [Holosha et al, 1999]. Ducks are known to nest on the Pripyat Inlet, but an assessment of leakage from PVLRO Neftebaza into Pripyat Inlet [Kulachinsky et al, 1996] shows that this is insignificant in comparison to the leaching of activity from the bottom sediments. Thus the leaching of activity from PVLROs into surface waters is unlikely to significantly contribute to the activity in ducks. However, for the PVLROs (Neftebaza and the western and south-western areas of Ryzhy Les and St. Yanov) and the regions of contaminated soil which are flooded by surface water, the possibility of ducks nesting directly on the dump, cannot be ruled out.

Within the current project, it has been estimated that, for an adult ingesting 1kg of contaminated meat from ducks nesting on the Cooling Pond, a dose of 0.6mSv would be received. The activity concentration in ducks nesting on a contaminated surface water body is judged to depend on the activity concentration in the water and on the biological functions of the ducks.

According to the monitoring data of ‘RADEK’, the average water activity of 90Sr in the Cooling Pond dropped from 7.4 Bq/l in 1987 to 1.8 Bq/l in 1998. For year 1999, RADEK reported the following average groundwater concentrations of 90Sr beneath the PVLROs [Skalsky et al, 2000]:

- Ryzhy Les – 2.7 Bq/l - St. Yanov – 0.7 Bq/l - Stroybaza – 65 Bq/l - Neftebaza – 13 Bq/l - Chistogalovka – 1.25 Bq/l

However, the maximum 90Sr concentrations measured by various organisations in the boreholes in the vicinity of these PVLROs were several orders of magnitude higher than average concentrations reported by RADEK [Skalsky et al, 2000]:

- Ryzhy Les – 30,000 Bq/l (1992, trench 20), 16000 Bq/l (1998, trench 22) - St Yanov – 3,990 Bq/l (1995, trench 14) - Neftebaza – 613 Bq/l (1998, trench 4) - Stroybaza – 102 Bq/l (1998 Sector 1.5)

Based on the above data, it is feasible that during surface flooding of the PVLRO areas with groundwater close to the surface, concentrations of contaminants in the resulting marshes may be comparable to those in the Chernobyl Cooling Pond. Thus, for ducks nesting on the surface of flooded waste dumps, it is possible that the accumulation of activity within the ducks will be of the same order as that measured for ducks nesting on the shores of the Cooling Pond. Based on the available

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 123 information, it seems possible that via this pathway, dumps flooded by surface water may lead to relatively high doses (~ mSv/y) to hunters outside the Exclusion Zone.

It should be noted, however, that the high contamination reported for ducks nesting on the Cooling Pond may not be representative for those nesting on flooded dumps. In particular, the groundwater contamination levels quoted above for the PVLROs have never actually been measured in the surface waters in the vicinity of the dumps.

 ([SRVXUHZLWKLQWKH([FOXVLRQ=RQH Professionals working within the Exclusion Zone receive doses arising from the waste dumps via direct exposure and via the inhalation of radioactive dust. In addition to professionals, it cannot be guaranteed that illegal settlers will not gain access to the heavily contaminated sites during the period of institutional control. Within the Exclusion Zone there are three levels of fencing: around the (30km) Exclusion Zone; around the 10km Zone; and around Buryakovka, Podlesny and the Industrial Zone (Promploshadka). However, due to the large areas involved, the fencing around the 30km and 10km zones is not fully controlled along the entire perimeter, and thus illegal settlers may gain access. For illegal settlers the current exposure pathways include direct exposure, atmospheric dispersion, ground/surface waters and the ingestion of plants or animals.

The human intrusion pathway is defined as the exposure resulting from: construction of houses on dumps, occupation of houses, ingestion of crops growing on dumps and irrigated with contaminated water, and drinking of water from a well drilled into a dump. Although the access of illegal settlers to contaminated sites within the Exclusion Zone at present cannot be ruled out, the site is currently patrolled and any illegal settlers are expelled. Thus during the period of institutional control, exposure via the human intrusion scenarios above is unlikely and has been neglected. However, following the termination of institutional control, the probability of the human intrusion scenarios significantly increases.

For the estimates of doses resulting from human intrusion, made within the current project, it has been assumed that institutional control will continue for 100 years from the present.

(i) Direct Exposure For professionals working within the Exclusion Zone, one of the principal exposure pathways is via direct exposure during movement within the site and transport to and from the site. Direct exposure is from contaminated soil, trees, buildings etc.

The individual doses to staff belonging to the organisations operating within the Exclusion Zone estimated in 1997 are as follows [Kholosha et al, 1999]:

SSE Complex 1.8 mSv/y ISTC Shelter 4.0 mSv/y ChNPP 6.5 mSv/y

The factors determining the contribution of individual dumps to the direct exposure of individuals are:

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 124 - Location of dump with respect to access routes - Activity contained within the dumps - Containment of the waste - Vegetation cover

Contaminated soil within the Industrial Zone, is judged to contribute significantly to the direct exposure of personnel due to the fact that personnel activities are largely concentrated within this area. Roads accessing the site go through either PVLRO Ryzhy Les, or Stroybaza, or Yanov, Neftebaza and Kopachi. Thus these PVLROs contribute significantly to the doses received by visitors and workers accessing the ChNPP by direct exposure.

For Ryzhy Les, the direct exposure rate 1m from vegetation on Trench No 22 has been estimated as 29 µSv/h, based on experimental data on the accumulation of radionuclides in the vegetation [Kashparov, 1999]. For an illegal settler being exposed for one week per year, this results in a dose of 4.9 mSv/y.

(ii) Exposure from atmospheric dispersion Exposure within the Exclusion Zone via atmospheric dispersion can be the result of:

- Strong winds lifting contaminated dust; - Fires releasing activity contained in trees or topsoil; - Dust emissions generated during the movement of personnel and vehicles on site; - Dust emissions generated as a result of activities impacting directly on the waste.

The critical exposure group for this pathway has been identified as firemen working to fight fires that regularly occur within the Exclusion Zone. Based on the maximum atmospheric activity concentration of 20 Bq/m3 from fires [Marchenko & Doroshenko, 1997], doses to firemen of 0.2 mSv/y have been estimated. This estimation conservatively neglected any protection obtained from respiratory equipment worn by firemen.

In ~100 years doses due to forest fires are judged unlikely to increase, because the activity concentration in vegetation is not expected to increase over this time period.

Contamination within the Industrial Zone contributes significantly to the dose to personnel via this exposure pathway. Inhalation of radioactive dust generated during the movement of personnel and transport vehicles on the site, leads to significant doses to personnel working within the Industrial Zone. In its current state, any activities directly impacting on the contaminated soil within the Industrial Zone also pose a significant risk of exposure to personnel due to the inhalation of dust generated. This is likely to pose an increasing risk in the future due to the planned operations associated with the renovation of the Unit Shelter, construction of waste management facilities and the decommissioning of Chernobyl NPP. In addition, emergencies within the Industrial Zone leading to radioactive dust emissions, such as fires and falling of contaminated waste during transportation, are associated with a significant risk of exposure to personnel.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 125 At present, the PZROs are unlikely to pose a significant risk via this pathway due to the waste being contained in engineered trenches or vaults and the absence of any trees in the vicinity of the waste. However, in the future, there is a risk of erosion and the dispersion of contaminated dust.

Of the PVLROs, Ryzhy Les and Stantziya Yanov are likely to contribute most significantly to the dose via this exposure pathway, since in both cases the dumps are forested with the waste relatively near the surface. The radionuclide accumulation in vegetation on Trench No 22 at Ryzhy Les is given in [Kashparov, 1999]. Using this data and Gaussian plume dispersion, it was conservatively estimated that the dose to an individual 100 m from a fire on the Trench would be ~0.01 mSv.

Areas of contaminated soil within the Exclusion Zone are likely to contribute significantly to the on-site dose to illegal settlers from both fires and wind blown dust.

(iii) Exposure via human intrusion Exposure due to human intrusion is only considered to be likely to take place following the termination of institutional control, which is assumed to occur in 100 years.

The maximum concentration of Sr-90 in groundwater in the future has been predicted near PVLRO Kompleksny to be 3.7E+04Bq/l [Bugai, 2000]. Based on this, the dose to an individual abstracting all their drinking water from a well dug into Kompleksny in ~100 years was estimated as 0.6 Sv/y.

The doses from house construction and residential scenarios for PZRO Buryakovka in 100yrs, 300yrs and 10,000yrs from present have been estimated within the current project using methodology from [NEA, 1986]. It was found that the highest doses were incurred in 100yrs, with a dose of ~0.3 mSv/y from the residential scenario. The concentration of Ra-226 was found to peak in approximately 180,000 years, however, the dose from the inhalation of radon was never found to exceed the dose due to house occupancy experienced immediately following the termination of institutional control, which will be dominated by the contributions from Sr-90, Cs-137 and Am-241.

The contribution of the individual waste dumps to exposure via human intrusion depends on:

- Activity contained within the dump in ~100 years - Presence of any barriers/fences around the dumps in ~100 years - Waste containment

There is currently fencing around the Exclusion Zone, around the ‘10-km Zone’, and around the Industrial Zone. However, at the end of the period of institutional control this fencing is unlikely to pose a significant protection against human intrusion.

For the Industrial Zone, small quantities of long-lived waste within the surface soil layers have been identified. Following the termination of institutional control, there is the potential for significant doses to be incurred as a result of human intrusion.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 126 For the PZROs, the waste is contained within engineered concrete vaults or trenches which is likely to reduce the potential for human intrusion. However, due to the relatively high activities contained in these facilities, the consequence of any such intrusion would be significant. Thus, in the case of the PZROs there is the potential for significant individual doses to be incurred as a result of human intrusion.

For the PVLROs the waste is not containerised and there is no fence around the individual dumps. Hence, the potential for human intrusion into the PVLROs is significant. However, in ~100yrs due to radioactive decay, activities in the dumps and in the groundwater below the dumps are expected to decrease. Based on the concentration of Sr90 of 16,000 Bq/l in a borehole in the vicinity of Ryzhy Les in 1998 [Skalsky et al, 2000], the doses from the abstraction of drinking water from the borehole in ~100y have been estimated to be of the order of 20 mSv/y.

For a minimum-engineered facility within the Chernobyl Exclusion Zone reference levels (defined as values of specific activity for given radionuclides at the time of disposal which if exceeded would result in doses from human intrusion at some time in the future exceeding the dose limit) were determined for the house occupancy scenario. A minimum-engineered facility is defined as having the following attributes [NEA, 1986]:

- Surface trenches to a depth of 8m, with a 1m soil capping. - Waste above water table. - Waste placed in reasonably permeable rock, underlain by less permeable rock. - Site consists of 9 trenches, ~700 m long and 25m wide. - Stream located fairly close to site at ~2.5km.

Reference levels for a minimum-engineered facility in the Exclusion Zone leading to a annual dose of 1mSv/y for each radionuclide following the termination of Institutional Control, via the house occupancy scenario, are shown in Table 50. These levels were estimated using the methodology from [NEA, 1986].

7DEOH5HIHUHQFHOHYHOVIRUDPLQLPXPHQJLQHHUHGIDFLOLW\LQWKH([FOXVLRQ=RQHIRU KRXVHRFFXSDQF\VFHQDULR 5DGLRQXFOLGH 5HIHUHQFHOHYHO%TJ Sr-90 60 Cs-137 40 Ra-226 0.09 Pu-238 300 Pu-239 100 Pu-240 100 Pu-241 800 Pu-242 100 Am-241 30

For the α-emitting radionuclides, Pu-239, Pu-240, Pu-242 and Am-241, reference levels are within the range of 10-103 Bq/g. For waste with a radionuclide composition that is characteristic of the Chernobyl Unit-4 fuel, the presence of long-lived waste (according to the IAEA criterion of 400 Bq/g alpha) within a minimum-engineered

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 127 near-surface facility leads to doses associated with house occupancy that are greater than 10 mSv/y (ICRP recommended dose limit for intervention in relation to human intrusion scenarios [ICRP, 1998]).

(iv) Exposure from ground- and surface- waters Given that illegal settlers may currently gain access to contaminated sites in the Exclusion Zone, it is possible that they could ingest small amounts of contaminated water. For an individual ingesting 1l/y of contaminated groundwater in a shallow borehole at Ryzhy Les a dose of 0.4 mSv/y has been estimated (using a concentration of Sr-90 of 1.6E+04Bq/l in boreholes in 1998 [Skalsky et al, 2000).

In about 100 years, for an individual ingesting 1l/y of contaminated groundwater in the vicinity of Kompleksny a maximum dose of 1 mSv/y has been estimated (assuming maximum concentration of Sr-90 of 3.7E+04Bq/l in groundwater beneath Kompleksny in the future [Bugai, 2000]).

The factors determining the contribution of individual dumps to on-site doses from this exposure pathway are as follows:

- The activity contained within the dump - Whether the waste is saturated. - Waste containment - Fences/ barriers around waste dumps

Currently, doses from this pathway are unlikely to originate from the Industrial Zone and the PZROs, since these areas are fenced and settlers will be aware of the hazards. For the PVLROs and areas of contaminated soil, however, there is potential for illegal settlers/hunters to drink a small amount of ground/surface water in the vicinity of the waste dumps.

At the end of the period of institutional control, risks from this exposure pathway for the PZROs become increasingly significant, due to the termination of control of these sites. In particular, Kompleksny, for which the waste is saturated and the engineered containment is damaged, is judged to pose a significant risk in the future.

(v) Exposure from ingestion of plants and animals Illegal settlers gaining access into the Exclusion Zone, may be exposed via the ingestion of contaminated mushrooms, berries, and meat from wild animals. For illustrative purposes an estimate of doses from the ingestion of mushrooms and ducks has been made, based on consumption rates in the UK and measured concentrations reported for ducks nesting in the Cooling Pond (of 37Bq/g) and mushrooms picked in the Exclusion Zone (of 3.7-13Bq/g) [Holosha et al, 1999]. Assuming that contaminated foodstuffs make up all of the annual intake of poultry and mushrooms (30kg/y and 10 kg/y respectively) for illegal settlers, individual doses to adults of 20 and 1 mSv/y will result from ingesting contaminated ducks and mushrooms.

For waste dumps that are flooded by surface water doses of the order of 20 mSv/y to illegal settlers are possible via ingestion of contaminated ducks (see Section 4.3.2, where doses were assessed for ingesting 1kg of contaminated fowl).

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 128 For non-flooded dumps exposure via the ingestion pathway is largely due to the ingestion of mushrooms with associated doses of the order of mSv/y. The likelihood of illegal settlers picking mushrooms is judged to be greater for the forested dumps of Ryzhy Les and Stantziya Yanov.

 6XPPDU\RIGRVHVIURPHDFKH[SRVXUHSDWKZD\ For exposure pathways, other than human intrusion, the ICRP recommended risk constraint is 0.3 mSv/y [IAEA, 1999]. For the human intrusion pathway the ICRP recommended dose constraint is 10 to 100 mSv/y [ICRP, 1998], which is greater than for the other exposure pathways, reflecting the lower probability of human intrusion scenarios. Dose constraints imposed by the Ukrainian Hygenic Regulations, 2000, are more stringent than those specified in the international guidelines, with dose constraints of 0.04mSv/y during the period of institutional control and 1-50 mSv/y from human intrusion pathways (see Section 2.2). Due to the fact that the regulatory system on radioactive waste disposal is currently under development in the Ukraine, unacceptable risks associated with the waste dumps have been defined, within the current project, as those which exceed the international guidelines.

A summary of dose estimates from sources within the Exclusion Zone is shown in Table 51. The doses which exceed the ICRP dose constraint are highlighted.

7DEOH6XPPDU\RIGRVHHVWLPDWHVIURPVRXUFHVZLWKLQ([FOXVLRQ=RQHIRULQGLYLGXDO H[SRVXUHSDWKZD\V Exposure Exposure outside Exclusion Zone Sv/y Exposure inside Exclusion Zone Sv/y pathway (Source of exposure) (Source of exposure) Current In 100 yrs Current In 100 yrs Ground & 3E-09 1E-06 4E-04 1E-03 surface waters (All sources) (All sources) (Ryzhy Les, from (Kompleksny, from ingesting 1 l of ingesting 1 l of groundwater) groundwater) Atmospheric 2E-08 No increase 2E-04 No increase dispersion (Forested areas) (Forested areas) (Forested areas) (Forested areas) Ingestion of 6E-04 No increase 2E-02 No increase plants & birds (Dumps flooded (Flooded dumps) by surface water) 1E-03 (Non-flooded dumps) Human intrusion N/A N/A N/A 6E-01 (Well in Kompleksny) >1E-02 (LL LILW, residential scenario) 2E-02 (Borehole in Ryzhy Les) Direct exposure N/A N/A 6E-03 (for workers <5E-03 from all sources) 5E-03 (for illegal settlers from Ryzhy Les)

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 129 Marginal contribution to dose

Approx. equal to ICRP dose constraint (10-100 mSv/y for human intrusion, 0.3 mSv/y for all other pathways)

Greater than ICRP dose constraint

N/A – not applicable In relation to off-site radiological risk, both currently and in ~100 years, the ground /surface water and atmospheric dispersion pathways only contribute marginally to individual doses. Individual doses outside the Exclusion Zone are judged to be dominated by the ingestion of birds/animals. The ingestion of ducks nesting on waste dumps and contaminated soils flooded by surface water, may lead to doses greater than 0.3 mSv/y to a few individuals hunting outside the Exclusion Zone. However, these doses are based on data relating to the contamination of ducks nesting on the Cooling Pond, and the high contamination reported for ducks nesting on the Cooling Pond may not be representative of those nesting on flooded dumps.

In relation to the current on-site radiological risk to illegal settlers, the ingestion of birds nesting on flooded dumps is the critical pathway. However, the ingestion of mushrooms growing within the Exclusion Zone and direct exposure to contamination are also associated with significant doses that may exceed the ICRP dose constraint of 0.3 mSv/y.

For personnel working within the Exclusion Zone, significant doses are currently associated with direct exposure and the inhalation of radioactive dust originating from waste within the Industrial Zone.

Following the termination of Institutional Control, there is the potential for significant on-site doses to be incurred as a result of human intrusion. It has been shown that, for a minimum-engineered facility in the Exclusion Zone, the presence of long-lived waste will lead to doses greater than 10 mSv/y via the house occupancy scenario. The abstraction of drinking water from a well dug into Kompleksny may lead to doses greater than 100 mSv/y, which exceeds the upper limit of the ICRP recommended dose constraint for human intrusion.

 3ODQQHGRURQJRLQJDFWLYLWLHVZLWKLQWKH([FOXVLRQ=RQHLPSDFWLQJRQULVNV DULVLQJIURPZDVWHGXPSV

 )XWXUHRSHUDWLRQVZLWKLQ,QGXVWULDO=RQH The radioactive wastes present in the man-made layers at the ChNPP Industrial Zone pose a hazard to the following future operations:

- Activities associated with the renovation of the Unit Shelter, including the construction of reprocessing facilities for liquid and solid waste (area layout, laying of foundations, etc.);

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 130 - Construction of reprocessing facilities for liquid and solid waste from the Chernobyl NPP and Unit Shelter (Facility for Liquid Waste Treatment and Industrial Complex for Solid Radioactive Waste Management) - Chernobyl NPP decommissioning; - Construction of the new Shelter (Shelter-2); - Unit Shelter transformation into an ecologically safe system.

The Ukrainian Government has adopted a set of documents detailing the decommissioning of the Chernobyl NPP and the works to transform the Unit Shelter into an ecologically safe system. These documents specify the time schedule for the removal of those wastes that are situated in certain places within the Industrial Zone, as well as for all the waste as a whole.

In accordance with the document “Conception of Unit Shelter waste management”, the stages and schedule of the waste management activities have been specified as follows:

- Preparation (years 1997-2004); - Removal of fuel containing materials (years 2004-2015); - Retrieval of high-level wastes (according to the Ukrainian classification, years 2010-2030); - Retrieval of remaining long-lived wastes, and disposal of short-lived wastes (years 2015- 2050); - Disposal of long-lived wastes (years 2050-2100).

The remediation of the ChNPP Industrial Zone needs to be co-ordinated with the above stages of ChNPP decommissioning and Unit Shelter transformation. The main arguments for co-ordinating the work schedules are as follows:

- The waste management activities (Liquid Waste Processing Facility and Industrial Complex for Solid Radioactive Wastes Management), the Chernobyl NPP decommissioning, and the retrieval of fuel containing materials from the Unit Shelter are likely to lead to some further contamination of the surrounding area. - Removal of the man-made layer at the Industrial Zone would significantly complicate the process of waste retrieval from the Unit Shelter, if the activities were not adequately co-ordinated. - The renovation of the Unit Shelter may lead to further contamination of the surrounding area.

The complete removal of contaminated soil prior to the retrieval of high level and long-lived wastes from the Unit Shelter will only result in secondary contamination of soil within the Industrial Zone. However, partial retrieval of contaminated soil will be required during the construction of the waste management facilities within the Industrial Zone, the establishment of the infrastructure for the Shelter (radiological control area, transformer substation, warehouses, etc) and the construction of the new Shelter. Thus, the man-made layer will have to be partially removed in parallel with the preparatory stage for retrieval of waste from Unit 4.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 131 It is planned that the removal of the man-made layer will be completed within 15 years, in line with the accepted concept of short-term stabilisation of the Unit Shelter, and the schedule for the construction of the new Shelter.

 )DFLOLWLHVSODQQHGDW6WUR\ED]D Facilities linked to work on Shelter-2 will be constructed on the territory of PVLRO Staraya Stroybaza. A preliminary scheme for the construction work suggests that Sectors 1.1 and 1.2 of the PVLRO will be affected. It has been estimated that the total area occupied by the construction site within these Sectors is 54ha:

1. Site for Shelter-2 itself is approximately 400 m x 350 m = 14 Ha 2. Industrial Zone related to work on Shelter-2 (storage of construction materials, equipment etc.) is approximately 1000 m x 400 m = 40 Ha.

Waste within the areas of the PVLROs that are affected by the construction work will have to be retrieved.

 5LJKW%DQN3URWHFWLYH'DP The Right Bank Protective Dam is currently under construction. The purpose of the dam is to prevent contaminated soils that are located on the right-bank of the Pripyat River in the vicinity of ChNPP from being flooded by the spring snowmelt. The area that lies within the zone that is protected by this dam includes PVLRO Neftebaza. Following construction of the dam, the water level in the Pripyat Inlet will be kept approximately constant throughout the year (at about 105m above sea level) and the flooding of trenches at Neftebaza by surface water should not occur.

The approximate scheme of the dam is shown in Figure 41.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 132  3ULRULWLVDWLRQRIZDVWHUHWULHYDO The criterion for an unacceptable current risk is doses to the public in excess of the ICRP constraint of 0.3 mSv/y [IAEA, 1999]. An unacceptable risk associated with human intrusion scenarios is doses to the public greater than the IAEA recommended dose constraint of 10-100 mSv/y [ICRP, 1998]. The Ukrainian Hygienic Regulations, 2000, impose more stringent dose constraints (see Section 2.2). However, since the regulations on radioactive waste disposal are currently under development in the Ukraine, within the current project unacceptable risks have been defined according to the international recommendations.

For those dumps for which risks are judged to be unacceptable and conditions are not in compliance with international guidelines, remediation is required. Where simple remediation measures are unable to reduce risks to those which are acceptable or conditions at the site cannot be brought in line with international guidelines on near- surface disposal, waste retrieval is required.

The near-surface disposal of long-lived waste does not comply with IAEA recommendations and is also associated with risks greater than the dose constraint for human intrusion scenarios. Thus, the retrieval of long-lived waste in dumps within the Exclusion Zone is required.

Significant risks are associated with dumps which are continuously or periodically flooded by surface water, although further assessments are required to quantify this risk with greater accuracy. The flooding of disposal sites by surface water, to the extent that the ability of the site to meet the safety requirements is compromised, is not in compliance with international recommendations. Remediation of these sites is required, although further assessments are necessary to determine whether the waste should be retrieved.

In addition, where construction work is planned at a site, waste retrieval is required.

The waste dumps have been assigned to the following three categories:

Category Description A Waste retrieval is required as soon as possible following the completion of remedial option studies and detailed safety assessments. B Waste retrieval is required prior to the termination of institutional control. Storage is only possible for as long as conditions are considered safe. A detailed risk assessment of the site and remedial option analyses are required. C Further study of the radiological risk from the site and remedial option analyses are needed to determine whether waste retrieval is required. Waste disposal at the site may be possible following remediation, providing the conditions comply with international and Ukrainian requirements for near surface disposal.

The logic used to assign categories to the individual dumps is shown in Figure 42 and detailed below.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 133 (i) Industrial Zone Category A The current state of waste in the Industrial Zone does not comply with existing norms and standards on waste disposal and retrieval of waste is required as soon as possible. High level and long-lived waste (IAEA classification) has been identified within the surface man-made layers, which is not in compliance with IAEA recommendations for near- surface disposal. The presence of long-

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 134 Construction work planned at the site

Yes No Conditions cannot be brought in line with regulations on near surface disposal and/or doses Category A cannot be reduced to those which are acceptable by the implementation of remedial measures.

A judgement is required based on Yes further assessment.

Storage conditions can be made safe without retrieval in the short term and there is no spreading of contamination. Category C

Yes No

Category A Category B

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 135 lived waste in a minimum-engineered facility is associated with doses via human intrusion greater than the dose constraint. In addition waste within the Industrial Zone is judged to pose a significant risk to personnel working within the site via direct exposure and the inhalation of contaminated dust. Doses to workers within the Exclusion Zone from direct exposure were measured to be greater than 1mSv/y in 1997.

The wastes in the man-made layers pose a hazard to activities associated with the renovation of the Unit Shelter, construction of waste management facilities and ChNPP decommissioning. The retrieval of waste from the Industrial Zone is to be co-ordinated with the planned stages of ChNPP decommissioning and Unit Shelter renovation. Immediate partial retrieval of waste from the Industrial Zone is required, with further retrieval to be carried out in parallel with the preparatory stage of waste retrieval from the Unit Shelter. Waste retrieval from the Industrial Zone is to be completed within 15 years, in line with the accepted concept of short-term stabilisation of the Unit Shelter, and the schedule for the construction of the new Shelter.

(ii) PZRO Kompleksny Category A Retrieval of all waste from PZRO Kompleksny is required as soon as possible. The storage conditions of the waste at the PZRO do not comply with IAEA recommendations. There are depressions visible on the surface due to localised subsidence and the waste is saturated, with the level of groundwater being 0.5-0.7m above the bottom of the waste. It is expected that contamination of groundwater in the vicinity of this facility is likely to increase in the future. Following the termination of institutional control, there is potential for significant on- site doses to be incurred as a result of human intrusion into this dump. Doses greater than 100 mSv/y are estimated to result from an individual drilling a well into Kompleksny and abstracting drinking water after institutional control has been stopped.

Furthermore, from the 1996 survey of the PZRO, a maximum activity of TRU of 45 Bq/g was estimated. However, due to the small number of measurements on which this estimate was based, it is feasible that long-lived waste (IAEA classification) is present in the PZRO.

(iii) PZRO Podlesny Category B The waste in Podlesny is contained within concrete compartments and grouted, but fractures within the facility have been identified. The PZRO is an above surface facility with the groundwater table 5.5-7m below the surface, and at present the facility is judged to pose little risk of groundwater contamination. Based on assessments performed by SSE Complex, PZRO Podlesny has been identified as containing long- lived waste according to the IAEA classification system, which is not in compliance with the IAEA recommendations for near-surface disposal, and it is associated with doses greater than the dose constraint

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG 136 for human intrusion. However, the methods used to obtain the data are unknown and adequate verification of the data has not been possible. Thus additional characterisation of the PZRO is required.

Proposals have been put forward for the improvement of the storage conditions at this facility, which are designed to ensure the safe storage of the waste for 20 years (for details see Section 4.6). Implementation of these improvements is required as soon as possible. Assuming implementation of the improvements, after approximately 20 years the retrieval of waste from the PZRO will be required unless, following further characterisation, it is shown that the PZRO does not contain long-lived waste. Additional risk assessments and remedial option analyses are required prior to taking the final decision relating to waste retrieval.

(iv) PZRO Buryakovka Category B It has been estimated that small amounts of long-lived waste (~0.026% of the total volume) are being stored at Buryakovka, which is not in accordance with IAEA recommendations and is associated with doses greater than the dose constraint for human intrusion. Retrieval of this long-lived waste is required in the medium term. Placing this relatively small quantity of long-lived waste will present a potential problem. In addition the current waste acceptance criteria do not comply with IAEA requirements for near-surface disposal. Thus it is recommended that the limit for alpha activity of the waste disposed at the facility be reduced to the IAEA limit of <400Bq/g immediately. Following implementation of the above measures it is likely that PZRO Buryakovka will satisfy international standards, and disposal of short- lived waste at this facility can continue.

In addition to the storage of waste in the trenches, there is an open-air store for contaminated machinery at Buryakovka. The disposal of waste in the open-air store does not comply with IAEA recommendations, and the waste needs to be retrieved. A further study is required to determine the inventory of the store. Decontamination and washing of the machinery may be appropriate with the subsequent volume reduction, conditioning and disposal of waste contaminated to the levels higher than free release limits.

(v) PVLRO Staraya Stroybaza Category A Retrieval of waste is required as soon as possible for those areas of the PVLRO affected by the planned construction of facilities linked with the work on Shelter-2. The preliminary scheme of the work suggests that the construction site will be located within Sectors 1.1 and 1.2 with 54 Ha, out of the total area of the PVLRO of 186 Ha, being affected. For the affected areas, waste retrieval is required from both waste dumps and contaminated surface and near-surface soil layers.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 137 Category B Localised regions of long-lived waste (according to the IAEA classification) are expected within the PVLRO, which does not comply with IAEA recommendations for near-surface disposal of radioactive waste (See Section 4.2). For Sector 2.1 of Ryzhy Les it has been estimated that approximately 0.45% of the waste is long-lived. Given the location of Staraya Stroybaza, the proportion of long-lived waste is expected to be equal or greater than that identified for Sector 2.1. For those areas of the PVLRO not affected by the construction of Shelter- 2, the retrieval of long-lived waste is in principal required as soon as possible, following further characterisation of the site. However, since it is difficult to locate such a small proportion of long-lived waste, it has been placed within category B for retrieval before institutional control ends.

Category C Those areas of the PVLRO not affected by the construction work and containing short-lived waste have been designated as Category C. Adequate isolation of the radionuclides from the environment is not achieved in accordance with the IAEA criteria for near surface disposal. Remediation of the area is required to prevent the bio- migration of radionuclides and the dispersion of radionuclides in the atmosphere and via water infiltration/percolation. A detailed assessment of the site and feasibility study of possible remediation options should be performed. Further study relating to the radiological risk from the area needs to be performed to determine whether waste retrieval is required in the future.

(vi) PVLRO Ryzhy Les Category A The disposal of waste at Sector 2.1 of PVLRO Ryzhy Les does not comply with IAEA guidelines on waste disposal. Three out of 45 trenches within the sub-sector D-1 have been identified as possibly containing long-lived waste (IAEA classification), with the estimated percentage of long-lived waste in Sector 2.1 being 0.45%. The retrieval of long-lived waste from Sector 2.1 is required as soon as possible, following completion of characterisation studies and remedial option analyses.

Category C Waste dumps and contaminated soils in the western and south-western areas within Sector 2.1 are seasonally flooded by surface water. This does not comply with IAEA requirements for near-surface disposal. Also the available data indicate that doses above the recommended limit of 0.3 mSv/y may result both on and off-site from the ingestion of contaminated ducks. However, a conclusive judgement in relation to the doses from the flooded dumps cannot be made on the basis of the available data. Further assessments are required as soon as possible to determine the risks presented by the flooded dumps. There is a need to verify the measurements of contamination in the surface water in the vicinity of the dumps and to implement a programme of studying the contamination of water birds in the Exclusion Zone.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 138 Due to the direct access of the waste by the biosphere and the spread of contamination from the dumps, remediation of the flooded dumps/soils is required as soon as possible. Based on the results of the detailed risk assessment, remedial option analyses should also be performed to determine whether remediation is sufficient to ensure the safe disposal of waste or whether waste retrieval is required. The retrieval of waste from the flooded dumps may not have a significant impact since the groundwater contamination by the mobile radionuclide Sr-90 has already taken place.

Category C The remainder of Sector 2.1, plus Sectors 2.2-2.6 are not flooded by surface water and contain short-lived waste. However, waste within Ryzhy Les poses a significant risk of exposure to illegal settlers within the Exclusion Zone via direct exposure (~5mSv/y) and via the ingestion of mushrooms (~1mSv/y). Also, adequate isolation of the radionuclides from the environment is not achieved in accordance with the IAEA criteria for near surface disposal. Remediation of the area is required to prevent the bio-migration of radionuclides, the dispersion of radionuclides in the atmosphere and via water infiltration/percolation. A detailed assessment of the site and a feasibility study of possible remediation options should be performed. A further study relating to the radiological risk from the area needs to be performed to determine whether waste retrieval is required in the future.

(vii) PVLRO Neftebaza Category C (Subject to being dry following completion of Right Bank Protective Dam) Approximately half of Sector 5.1 of the PVLRO is located on the Pripyat floodplain with the other half located on a terrace. Out of a total of 225 waste dumps at the PVLRO, 49 (approximately 40% of the waste dumps in Sector 5.1) and approximately 50% of the contaminated soil layers in Sector 5.1 are located on the floodplain. This waste is either continually or seasonally flooded by surface water, which is not in compliance with IAEA recommendations for waste disposal. The available data indicate that doses above the recommended limit of 0.3 mSv/y may result both on and off-site from the ingestion of contaminated ducks nesting on the flooded dumps.

With the construction of the Right Bank Protective Dam, the flooding of Neftebaza with surface water is expected to cease, in which case the risks from the waste dumps will be reduced significantly. Thus completion of the dam should be assigned the highest priority. Further assessments are required, taking into account the impact of the dam and its lifetime, to determine the radiological risks associated with the dumps, along with remedial option analyses. If following completion of the dam, the waste dumps in the floodplain are still seasonally flooded by surface water, then retrieval of the waste is required as soon as possible. Remediation to prevent the bio-migration of radionuclides

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 139 and the dispersion of radionuclides via water infiltration/percolation is to include those regions of contaminated soil within the Pripyat floodplain PVLRO Neftebaza.

Category C The waste in the PVLRO that is located above the floodplain (Sectors 5.2 and 5.3 and the terraced area of Sector 5.1) is not flooded and is classified as short-lived waste (IAEA classification system). This waste has been designated as Category C. Adequate isolation of the radionuclides from the environment is not achieved in accordance with the IAEA criteria for near surface disposal. Remediation of the area is required to prevent the bio-migration of radionuclides and the dispersion of radionuclides in the atmosphere and via water infiltration/percolation. A detailed assessment of the site and a feasibility study of possible remediation options should be performed. A detailed assessment of the radiological risk from the area needs to be performed to determine whether waste retrieval is required in the future.

(viii) PVLRO Stantziya Yanov Category C Waste dumps and contaminated soils in the western and south-western areas within Sector 3.5 are seasonally flooded by surface water. This does not comply with IAEA guidelines for near-surface disposal. Also available data indicate that doses above the recommended limit of 0.3 mSv/y may result both on and off-site from the ingestion of contaminated ducks. Further assessments are required as soon as possible to determine the risks presented by the flooded dumps. There is a need to verify the measurements of contamination in surface water in the vicinity of the dumps and to implement a programme studying the contamination of water birds in the Exclusion Zone.

Due to the direct access of the waste by the biosphere and the spread of contamination from the dumps, remediation of the flooded dumps/soils is required as soon as possible. Based on the results of the detailed risk assessment, remedial option analyses should also be performed to determine whether remediation is sufficient to ensure the safe disposal of waste or whether waste retrieval is required. The retrieval of waste from the flooded dumps may not have a significant impact. Groundwater contamination by the mobile radionuclide Sr-90 has already taken place.

Category C The remainder of Sector 3.5, plus Sectors 2.3, 3.1-3.4 and 3.6-3.7 are not flooded by surface water and contain short-lived waste. Adequate isolation of the radionuclides from the environment is not achieved in accordance with the IAEA criteria for near surface disposal. Remediation of the area is required to prevent the bio-migration of radionuclides and the dispersion of radionuclides in the atmosphere and via water infiltration/percolation. A detailed assessment of the site and feasibility study of possible remediation options should be performed. Further study relating to the radiological risk from the area

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 140 needs to be performed to determine whether waste retrieval is required in the future.

(ix) PVLRO Peschannoe Plato Category C Waste in PVLRO Peschannoe Plato is classified as short-lived (IAEA). The PVRLO is situated relatively close to the Pripyat Inlet (at a distance of 100 m) but the groundwater table is 3.5-7m below the bottom of the waste and the PVLRO is not judged to pose a significant risk of exposure via the groundwater pathway. However, adequate isolation of the radionuclides from the environment is not achieved in accordance with the IAEA criteria for near surface disposal. Remediation of the area is required to prevent the bio-migration of radionuclides and the dispersion of radionuclides in the atmosphere and via water infiltration/percolation. A detailed assessment of the site and feasibility study of possible remediation options should be performed. Further study relating to the radiological risk from the area needs to be performed to determine whether waste retrieval is required in the future.

(x) Rassoha 1 and 2 Category B The open-air disposal of contaminated machinery within Rassoha 1 and 2, does not comply with IAEA recommendations, and the waste needs to be retrieved. Further study is required to characterise the waste currently stored at the sites. Decontamination and washing of the machinery may be appropriate with the subsequent volume reduction, conditioning and disposal of waste contaminated to the levels higher than free release limits.

(xi) Contaminated soils Category C The regions of highly contaminated soil within the Exclusion Zone do not meet the IAEA criteria for near surface disposal since there is no isolation of the waste from the environment. Washout of radionuclides from contaminated soils dominates the current off-site radiological risk via the ground/surface water pathway. Significant quantities of soils contaminated above the free release threshold (~50%) are situated on wetland areas which are periodically flooded by surface water. The contaminated soils also pose a risk of exposure via atmospheric dispersion and via the ingestion of contaminated plants/animals. Further assessments of the risks posed by the contaminated soils are required as soon as possible.

The remediation of regions of highly contaminated soil is required to prevent the bio-migration of radionuclides and the dispersion of radionuclides in the atmosphere and via water infiltration/percolation. However, remediation of the entire area of contaminated soil is not practical due to its large extent and further studies are required to address the issue of soil contamination and to identify feasible remedial options.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 141 (xii) Unsurveyed PVLROs (excluding Staraya Stroybaza) Category C For the other PVLROs, which include Stantziya Semikhody, Novaya Stroybaza, Kopachi, Pripyat, and Chistogalovka, the waste is classified as short-lived (IAEA) and in some cases is close to the free release limit according to SPORO-85. Adequate isolation of the radionuclides from the environment is not achieved in accordance with the IAEA criteria for near surface disposal. Remediation of the area is required to prevent the bio-migration of radionuclides and the dispersion of radionuclides in the atmosphere and via water infiltration/percolation. A detailed assessment of the site and a feasibility study of the possible remediation options should be performed. Further study relating to the radiological risk from the area needs to be performed to determine whether waste retrieval is required in the future.

(xiii) Unauthorised waste dumps Category A Waste disposal within the unauthorised waste dumps does not ensure the adequate isolation of radionuclides from the environment and is not in compliance with IAEA recommendations. Waste is to be retrieved from these dumps as soon as possible. It is the current practice to dispose of these wastes at Buryakovka. However, Buryakovka is 85% full and an extension may be required in the near future. Further investigations are required to identify the unauthorised dumps and to characterise the waste.

A summary of the results of prioritisation is shown in Table 52.

 5HPHGLDWLRQRIZDVWHGXPSV (i) Existing proposals for the improvement of storage conditions at Podlesny A project that is aimed at the improvement of the storage conditions at Podlesny has been designed by STC “KORO” [Antropov et al, 2000b]. The project comprises the following measures:

- Placement of a 30 mm thick asphalt surface on the 120 mm gravel base between the A-1 and B-1 compartments; - Placement of a 100 mm thick concrete cap on the radioactive waste stored in compartments A-1 and B-1; - Implementation of diking with dry sandy soil around the A-1 and B-1 compartments, 1m higher than the top of the waste; - Arrangement of a compacted clay cap, 600 mm thick, on the top of the sandy soil; - Covering of compartments by metal sheets to prevent inflow of precipitation; - Construction of a dam to the south of the storage facility in order to prevent flooding of the PZRO with the surface water; - Gully strengthening with a 300 mm layer of gravel, to the north of the storage facility in order to prevent erosion; - Diversion of surface water away from the PZRO, by changing the local topography and construction of drainage ditches ;

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 142 - Drilling of additional monitoring boreholes.

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6LWH 6HFWRU 7\SHRIGLVSRVDO RIZDVWHYROXPHLQ HDFK&DWHJRU\ $%& PVLRO Staraya Stroybaza 1.1-1.4 Waste dumps ~29 0.3 70.7 Top soil ~29 0.3 70.7 PZRO Kompleksny Engineered dump 100 Industrial Zone Man-made soil layers 100 PVLRO Neftebaza 5.1 Waste dumps 100 Top soil 100 5.2,5.3 Waste dumps 100 Top soil 100 PVLRO Ryzhy Les 2.1 Waste dumps 0.45 99.5 Top soil 0.45 99.5 2.2-2.6 Waste dumps 100 Top soil 100 PVLRO Stantziya Yanov 3.5 Waste dumps 100 Top soil 100 2.3, Waste dumps 100 3.1- Top soil 100 3.4, 3.6-3.7 PZRO Podlesny Engineered dumps 100 PZRO Buryakovka Trenches 0.026 Contaminated machinery 100 store Rassoha 1 & 2 Contaminated machinery 100 dump Peschannoe Plato 6.0 Waste dumps 100 Top soil 100 Soils Top soil 100 PVLRO Stantziya Waste dumps and top soil 100 Semikhody PVLRO Novaya Stroybaza Waste dumps and top soil 100 PVLRO Kopachi Waste dumps and top soil 100 PVLRO Pripyat Waste dumps and top soil 100 PVLRO Chistogalovka Waste dumps and top soil 100 Unauthorised dumps Waste dumps 100

These measures are designed to ensure the safe storage of waste within the A-1 and B-1 compartments for the next 20 years.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 143 (ii) Remediation of PVLROs and contaminated soil For those waste dumps assigned Category C above, remediation of the site is required in the short term along with further risk assessments to determine whether waste retrieval is required in the future.

For each of these dumps remedial options need to be assessed and feasibility studies performed before a final decision is made. Remedial options that should be considered include:

- Removal of trees growing on contaminated soil - Capping of the surface with an engineered soil cover - Implementation of a surface run-off collection/drainage system with treatment where required - Erection of fencing around the waste dumps

These countermeasures do not address the situation at the dumps and the sites of contaminated soil that are permanently or seasonally flooded by surface waters. The assessment of doses from these sources should be carried out as soon as possible. Then it will be possible to review potential countermeasures and the need for retrieval.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 144  ,PSOLFDWLRQVIRUZDVWHPDQDJHPHQW  %DFNJURXQG An Industrial Complex, Treatment and Disposal Facility (CTD) ‘Vector’ is planned to be constructed within the Exclusion Zone. Construction of the CTD is based on the ‘Comprehensive Programme for Radioactive Waste Management’ approved by the Ukrainian Cabinet of Ministers (Decree No.480 of April 29, 1996, amended by decree No.542 of April 4, 1999). The Programme specifies the plan to establish the Treatment and Disposal Facility for LILW as detailed in Table 53.

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The CTD design and the corresponding waste management system are based on the earlier estimated waste volumes and waste categories within the Exclusion Zone.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 145 This Section provides the following information:

• general description of the planned facilities (Section 5.2.1) • the waste streams which currently represent the basis for the CTD design and the corresponding waste management system (Section 5.2.2) • description of the foreseen waste management technologies (Sections 5.2.3 – 5.2.5) • a summary of LL-LILW and HLW streams based on the inventory results explained in the Sections 3 and 4 of this report (Section 5.3), and • an evaluation of the impact of the updated waste inventory data on the identification of the draft technical specifications for the future waste treatment/conditioning/storage and disposal facilities to be built for radioactive waste from the Chernobyl area (Section 5.4).

 ,QGXVWULDO&RPSOH[7UHDWPHQWDQG'LVSRVDO)DFLOLW\µ9HFWRU¶ &7' The main issues related to the existing plans for constructing the CTD are explained in the following sections.

 *HQHUDO The site for the construction of the ‘Vector’ Industrial Complex was selected according to the results of the full-scale comparative analysis of alternative options, and took into account all the summarised parameters. The legal protocol stipulating the selection of the site for the constructing the CTD was approved on December 18, 1991.

The selected site is located within the Exclusion Zone between the Pripyat and the Uzh Rivers. It is situated some 10 km from the Pripyat River and 8-9 km from the Uzh River. This site has been approved by a team of Western experts working as the Cassiopee Consortium in the framework of the corresponding TACIS - Project.

The general plan has been developed taking into consideration climatic conditions, the optimisation of technological production processes, health and safety, fire safety and construction regulations.

The Minister of Emergencies of the Ukraine has approved the first stage of constructing the ‘Vector’ complex. The construction started in 1998. The commissioning of the first facilities - infrastructure and two repositories (SRW-1 and SRW2-1) - is planned for 2002. The facilities of Stage 1 will provide for disposal of solid, inorganic and incombustible short-lived wastes of Chernobyl origin. The planned volume of waste to be disposed at the first stage is 500,000 m3. Storage and disposal facilities will occupy an area of 160 Ha.

The further development of the Vector complex into a unified treatment and disposal centre (CTD) for low and intermediate level radioactive waste is laid down in the Urkainian‘State Programme for Radioactive Waste Management’. The second stage

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 146 will include facilities for volume reduction/encapsulation and a storage facility for long-lived waste (SRW-3).

The companies that will supply radwaste will perform the functions of SRW collection, classification and primary processing, demolition of contaminated transport vehicles, and other large objects that are subject to shipment to the Treatment and Disposal Facility.

The CTD will perform the following functions:

• Acceptance of long-lived and short-lived radioactive waste from the supplier (solid, structurally stable, chemically inert, sorted in accordance with the physical condition, chemical composition, and treatment methods. The acceptance criteria are as follows: • - the specific activity of β−emitters < 3.7×106 Bq/g - the specific activity of α−emitters <3.7×105 Bq/g - the surface contamination by β−emitters < 1×107particles/cm2xmin - the surface contamination by α−emitters < 1×106particles/cm2×min - the dose rate at 0.1m distance from the waste surface < 10 mSv/h

• SRW transportation within the Exclusion Zone in accordance with [PBTRB, 1973] and [OPBS, 1983]; • Shipment of containers to the supplier of SRW for disposal; • Waste inspection; • SRW conditioning by incineration, compaction, cementing; • Treatment of secondary liquid radwaste (LRW) produced as the result of CTD operation; • Disposal of short-lived SRW with the equivalent dose rate at 0.1 m distance from wastes surface <1 mSv/h; • Storage of long-lived and short-lived SRW with the dose-rate at 0.1 m distance from waste surface between 1 mSv/h and 10 mSv/h; • Re-certification, disposal and long-term storage of radioactive sources; • Environmental monitoring • Fulfilment of radiation monitoring requirements • Physical shielding of SRW; • Provision of the Complex infrastructure operation.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 147 NPPs Research/medical Exclusion Zone Industrial Zone

93.0 3.3 1447.0 467.2

V1 = 2,010.5 Stage 1 Stage 2

untreatable for incineration for compaction XQWU DWDEOH

V3 = 500.0 V2 = 415.2 V2 = 61.4 V2 = 1033.9

treatment V4 = 376.8 V5 = 123.2

V = 1054.6 SRW 1 V = 361.3

SRW 2–1 V = 369.1

SRW–3 V = 324.2  )LJXUH:DVWHVWUHDPIORZFKDUW9ROXPHVJLYHQLQP

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG 148  (VWLPDWHVRIZDVWHDULVLQJVXVHGIRUVSHFLI\LQJ&7'

Current estimates of waste arisings for processing and disposal at CTD facilities are provided in Section 4. However, the existing specification was based on earlier assessments. Information on waste stream data from these assessments is provided below.

The CTD waste flow-chart is illustrated in Figure 43 [Novikov, 2000]. Previously estimated volumes of LILW solid waste to be processed and disposed of at the CTD are given in Table 54.

Origin Waste volumes (m3)Total m3 for compactible Untreatable incineration NPPs of Ukraine 15,000 25,000 53,000 93,000 Research and medical - 1,400 1,900 3,300 facilities (Radon) Unit Shelter 200 5,000 462,000 467,200 Exclusion Zone 400,000 30,000 1,017,000 1,447,000

Total 415,200 61,400 1,533,900 2,010,500 7DEOH9ROXPHVRIUDGZDVWHIRUSURFHVVLQJDQGGLVSRVDO

The table shows that the majority of wastes will originate from the Chernobyl Exclusion Zone. About 20% of the waste is suitable for incineration, 76% is untreatable. The CTD includes facilities for volume reduction and conditioning of waste (see Section 5.2.3). Volumes after treatment and conditioning are given in Table 55.

Waste type Volume Factor of SRW volume after processing m3 volume (m3) reduction

in containers in containers or in bulk for incineration 415,200 32 13,000 for compaction 61,400 8 7,700 untreatable 1,017,000* - 664,800 352,200 Total 1,510,500 685,500 352,200 * Waste from Exclusion Zone only 7DEOH5DGZDVWHYROXPHVDIWHUFRQGLWLRQLQJDW&7'

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG 149 The table demonstrates treatment reduces the volume of waste by 455,900 m3.

When specifying the capacity of CTD facilities, OSAT used LL-LILW waste arisings data from the PVLRO sectors given in Table 56.

 39/52 2YHUDOO 9ROXPH RI ///,/: 2YHUDOOYROXPHP ×  VHFWRU DFWLYLW\ ///,/: DFWLYLW\  6RLO 0HWDO 5RWWHG &RQFUHWH 7RWDO *%T P *%T ZRRG EULFN   2.1 Ryzhy 219,410 695 1,000.0 70.0 - 69.0 - 139.0 Les 3.1, 3.2, 3.3 2,997 226 1.6 11.4 1.0 3.0 1.0 16.4 Stantziya Yanov 5.1, 5.2, 5.3 38,665 3,965 355.0 77.2 12.0 26.0 7.0 122.2 Neftebaza 6.0 6,407 630 4.0 57.3 - - - 57.3 Peschanoye Plato Total: 267,479 5,516 1340.6 215 13.0 98.0 8.0 334.9 1). Low activity wastes only are contained in PVLRO sectors. 2). There is no way to determine the quantitative characteristics of long-lived radioactive waste in physical components (metal, soil, rotted wood, etc.) prior to being retrieved from PVLRO and sorted. 3). Indicated volumes of physical components present evaluation data and have a high degree of uncertainty.

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It is noted that OSAT arisings for the Shelter Local Zone, which were provided by Technocentre [Novikov, 2000], are based on the same values as in the current project. Estimates of radwaste volumes around units 1, 2 and 3 are also identical to those used in specifying CPD facilities. However, it was estimated that 250 m3 of long-lived wastes would be generated from the areas surrounding Units 1, 2 and 3. The wastes around these units have not been characterised and there is a high degree of uncertainty associated with this figure.

 ,QIRUPDWLRQRQWKHSUHVHQWDSSURDFKWRZDVWHWUHDWPHQWFRQGLWLRQLQJDQG SDFNDJLQJ The following technologies for treatment and conditioning will be provided at the CTD: • Incineration • Compaction • Cementation • Processing of secondary LRW • Hot technologies (management of radioactive sources).

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 150 Incineration Incineration is the most effective technology to reduce the waste volume to be disposed of. At the CTD it is planned to construct an incineration facility with the following characteristics:

• Composition of waste ⇒ Mixed wood with humidity up to 40% – not less than 35 %; ⇒ Textile, paper, rags, ribbon, polythene, plastic – up to 60 %; ⇒ Biological wastes (dead bodies of animals) – 4 % ⇒ Non-combustible mineral impurities – 1 %; ⇒ LRW (oils)- are burned in the afterburner chamber

• Facility capacity: up to 250kg/h (SRW) and up to 5 l/h (LRW)

• Volumes of SRW subject to incineration:

⇒ solid SRW - up to 2,000 m3/year. ⇒ biological wastes - 30 tonnes/year. ⇒ liquid combustible wastes - 30 tonnes/year.

• Specific activity: Specific activity should not exceed 3.7×103Bq/g (1×10-4 Ci/kg), for β- activity 3.7×102Bq/g (1×10-5 Ci/kg), for α - activity. Thus the facility does not accept long-lived wastes (IAEA categorisation) • Residual content of dust in off-gases – 0.02 mg/m3. • Degree of gas cleaning from dust - minimum 99.999% • Gas activity after cleaning: for γ-emitters – < 4.9×10-13 Ci/l. for β-emitters - < 4.0×10-14 Ci/l. for α-emitters - < 3.0×10-17 Ci/l.

• Degree of gas cleaning from HC1, HF, and SO3 – minimum 98%. Compaction

The following options have been reviewed when specifying parameters of the compaction facility: • disposal of non-compacted containerised SRW in the repository; • SRW is compacted in the compaction facility with the applied force of 800 tons, the casks are placed in containers;

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 151 • SRW disposal in the repository. SRW is compressed in the compaction facility with the applied force of 2,000 tons; the blocks are placed in containers

The following characteristics of the compaction facility were determined:

Work capacity 10 casks per hour Duration of compacting cycle 6 min Compacting factor ≤ 8 Nominal force of compaction 2,000 tons

Following the requirements of SPORO-85 the dose rate of SRW subject to compressing should be less than 0.5 µSv/hour at the distance of 10 cm from the package.

Cementation

Cementation is foreseen to fix the following waste types in a matrix: • Organic and inorganic absorbent materials coming from facilities for liquid waste treatment, that is produced in the result of the CTD operation; • Ash after incineration.

The facility capacity is as follows: • Inorganic absorbent materials - 0.6 m3/hour; • Organic absorbent materials ≈ 1.0 m3/hour; • Ash residue - 0.2 m3/hour; • Number of containers with the capacity of 0.2 m3, and which are filled by cement mass is 4 - 5 units per hour. • Portland cement of 400 or 500 brand mark is used as binding material.

Packaging Compressible, incombustible, intermediate-level wastes that contain short-lived radionuclides are delivered for compressing in 200-liter casks. The compressed bricks are loaded into concrete containers of KZNP-2,1 or KZNP-6,5 type, that are further delivered to the area of preparation of the containers for disposal, where they are cemented for the further disposal.

Non-compressible, non-combustible low-level radwaste containing short-lived radionuclides is put into a shipping container KNPU-10,5 or a container carrier with a reusable container and goes to SRW-2-1 storage facilities for further disposal.

Non-compressible, incombustible, intermediate-level SRW, containing short-lived radionuclides, are loaded into the concrete container of KZNP-2,1 type or KZNP-6,5 type, and are delivered to the area of the container preparation, and afterwards to the disposal site.

Combustible intermediate-level radwaste containing short-lived radionuclides with the maximum specific beta activity of 1×10-4 Ci/kg (3.7×103 Bq/g) and maximum alpha activity of 1×10-5 Ci/kg (3.7×102 Bq/g) will first be milled. Then it is put into

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 152 plastic bags and sent to the incineration installation. Ash produced by the incineration is put into 200l drums and sent to the cementation area. Following solidification, it is put into a concrete container of KZNP-2,1 or KZNP-6,5 type. Free space in a container is filled up with the cement mixture to enhance the effectiveness.

The containers meet the corresponding Ukrainian requirements.

The reinforced concrete container KZNP-2,1, was designed in the Ukraine for disposal (storage) of radwaste from group II and successfully tested in accordance with the requirements of standard GOST 16327-88. The main design and technical characteristics of the cask are listed below.

• External volume: 6.25 m3; • Internal volume: 2.1 m3; • Lifetime: >300 years; • External dimensions: length 1940 mm; width 1940 mm; height 1660 mm; • Internal dimensions: length 1500 mm; width 1500 mm; height 1000 mm; • Wall thickness: 220 mm; • Lid thickness: 300 mm; • Mass details: Container weight: 8,400 kg; Payload: 3,600 kg; Gross weight: 12,000 kg; Lid weight: 1,650 kg. Radwaste is put into a container through a removable lid.

A detailed description and evaluation of the specified container is given in [PBTRB, 1973].

The technical documentation for a reinforced concrete container KZNP-6,5 designed for disposal (storage) of radwaste of group II include the following specifications:

Dimensions: 2,2×2,2×2,45 m, volume: 6.5 m3; Wall thickness: 200 mm. Radwaste is put into this container in the same way as for the container KZNP-2,1. The container lid is secured with a special device during transportation. Modifications in the container KZNP-6.5 to make it a shipping container are at the stage of a technical project.

The metal container KNPU-10.5 designed in Ukraine for transportation and storage of radwaste of group I (low-level) and successfully tested in accordance with GOST 16327-88 requirements, can be considered similar to the ISO container:

Dimensions: 3,0×2,4×2,0, volume: - 10.5 m3; Wall thickness: 4.0 mm.

The construction of a reusable container that serves as a transport container and is to be used for SRW transportation and SRW discharge into the SRW-2 and SRW-2-1, is at the stage of detailed engineering development. The kit consists of a scoop-type

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 153 container (6 m3, 10 tonne), and a hermetically sealed van with a biological shield on the KrAZ chassis. The container is loaded and unloaded from the van by a hydraulic drive attached to the transport container.

For delivering SRW to the CTD will be used different containers loaded into special transport vehicles. Following types of packages are used:

• for transport from the enterprises/places that are located in the Exclusion Zone (including the Shop of Radioactive Waste Primary Processing (ZPPRO)): ⇒ reversible container of 6 m3 with the special van truck equipped with KrAZ chassis ⇒ metal container of 10.5 m3 ⇒ reinforced concrete container of 6.5 m3; ⇒ metal cask of 0.2m3;

• for transport from ‘Radon’ ⇒ metal cask of 0.2 m3; ⇒ containers for radioactive sources of KBN, KN, KIZ type.

 5DGZDVWHGLVSRVDOVWRUDJH Three types of disposal facilities are provided. Characteristics of the repositories are given in Table 57.

3DUDPHWHU 7\SHRIUHSRVLWRU\ 65: 65: 65: Structure Reinforced concrete reinforced concrete reinforced concrete foundation vault type repository vault type store Length , m 200.0 195.8 200.4 Width. m 29.0 18.0 22.3 Height, m 7.5 7.5 8.5 Type of SRW disposal Reinforced concrete Primary package Container (storage) container in bulk KZNP-6.5 KZNP-6.5 – 3 stores KNPU-10.5 KNPU-10.5 SRW volume, m3 18,000 18,000 13,000 Waste acceptance SL-LILW SL-LILW LL-LILW and SL

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Prior to the construction of the repository, the engineering and excavation activities will be carried out with the purpose to lay an underlying ‘screen’ made of bentonite clay with sand in 1:5 ratio, which will safely and reliably protect the environment from radionuclides.

Repository SRW-1 is designed to store low and intermediate level wastes, containing short-lived radionuclides to be held in reinforced concrete containers KZNP-6.5 (6.5 m3 volume).

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 154 This repository will have a reinforced concrete foundation 300 mm thick, 200 m long, and 29m wide, on the top of which the containers are placed by gantry crane. Below the foundation there will be a 1-m layer of materials with high sorption. The surface of the reinforced concrete plate is covered with asphalt. The sloping surfaces of the foundation will direct rainwater flow into the outlet channels with access to monitoring wells. Clean water from these wells will then flow into the open drainage system. Radionuclide contaminated water, with concentrations higher than ingestion limits, will be removed by vehicles for further treatment.

A gantry crane of 32 tones weight-lifting capacity and 32 meter span will be used for the loading of SRW containers. LRW containers will be transported by a specialised vehicle. When a repository is filled, containment will be ensured by filling the containers with an absorbent levelling layer, then by layers of clay (1m) and by local sand (0.3 m). Finally, the top surface is covered with an 0.3 m thick layer of soil.

Repository SRW 2-1 is a vault-type facility with 26 reinforced concrete compartments. Its dimensions are listed below: length 195.8 m, width – 18.0 m and height 7.5 m.

The repository is designed for low and intermediate level wastes containing short- lived radionuclides with a maximum dose rate of 100 mrem/h (~1mSv/h). Wastes will be disposed in bulk, in metallic containers KNPU-10.5, in the primary package with the help of mobile crane, with a weight-lifting capacity of 20 tonnes, moving on rails along the repository.

In the repository two sections will be filled by bulk waste and then are covered by a reinforced concrete slab and sealed. Protection from precipitation will be provided by layers of clay (0.1 m), local sand (0.3 m) and soil (0.3 m). Rainwater and effluent discharges from the waste will be directed to the sumps, constructed alongside the repository and connected to each section of the facility.

Facility SRW-3 will store:

• Low and intermediate level waste containing long-lived radionuclides in reinforced concrete containers KZNP-6.5 – ILW and in metallic containers KNPU-10.5 – LLW.

• Intermediate-level wastes containing short-lived radionuclides with dose rate from 100 to 1000 mrem/h (~1to 10 mSv/h) - in KZNP-6.5 containers.

In its design this repository is similar to the SRW-2-1 repository, and is designed as a reinforced concrete modular vault made of 27 sections. Its overall size is 200.4×22.3×8.5 m. The repository is filled with the help of the gantry crane with a weight-lifting capacity equal to 32 tones. Each section of the repository has natural ventilation. Rainwater and water leakage is collected by a piping system and wells. This system collects rainwater before the repository sections are closed.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 155 Following the Ukraine Senior State Health and Safety Doctor’s Decision No. 104 of March 6, 2000, the following Health and Safety regulations (GN 6.6.6. 054.2000) came in force:

‘1st Group Radiation and Health and Safety Specifications as to Personnel Protection while Radioactive Waste Disposal; and Acceptance (Non-Acceptance) Criteria of SRW Disposal in the Surface Storage Facilities’, and Methodical Recommendations ÌR 6.6.6. 055.2000 ‘Recommendations on Implementation of Radiation and Health and Safety Specifications as to Personnel Protection while Radioactive Waste (SRW) Disposal’.

The following activities should be carried out when designing SRW repository of any type: • analyse, record, and take necessary measures to limit the current exposure up to the dose rates specified in Table 58; • analyse, record, and take necessary measures to limit the potential exposure of the population critical group to dose rates, and risks specified in Table 58; • analysis of acceptance (non-acceptance) of SRW disposal in surface repositories, based upon the criteria in Table 59.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 156 Specifications Implementation Numerical Value Annual dose-rate limit Current population exposure to - with the state regulatory and exemption level gas and aerosol emissions, body’s monitoring - 0.04 for the period of water discharges resulting from mSv/yr institutional control the SRW repository normal - after exemption from the operation state regulatory body’s monitoring – 0.01 mSv/yr Reference risks for Potential exposure within the Occupational – 2×10-4 ⋅year-1 radiological period of monitoring by the Population critical group – consequences state regulatory body 2×10-5 ⋅year-1 Reference risks for Potential exposure within the Doses less than 50 mSv⋅year-1 – critical events∗ period of monitoring by the 1×10-2 ⋅year-1 state regulatory body Doses exceeding 50 mSv⋅year-1 – 2×10-5 ⋅year-1 Reference levels for Population potential exposure • Doses should not exceed 50 human intrusion during critical events caused by mSv/yr abnormal circumstances and • Within the limit 1-50 mSv/yr human involuntary interference, – separate consideration by after exemption from the state the regulators regulatory body’s monitoring • Below 1 mSv/yr – acceptable. * the risk of events that can cause lethal dose rates within a short period of time should not exceed 5×10-7 per year 7DEOH 0DLQVSHFLILFDWLRQVRISHUVRQQHOUDGLDWLRQSURWHFWLRQGXULQJ65: GLVSRVDO

SRW type Potential exposure Type of perspective Accepted type of doses, starting from exemption from state SRW disposal 300 years after regulatory body’s disposal monitoring within 300 years after disposal Short-lived Lower than 1mSv/yr Total, Surface limited Determined upon Higher than 1mSv/yr Limited Determined upon concurrence with but lower than 50 concurrence with the the state mSv/yr state regulatory regulatory bodies bodies

Long-lived Higher than 50 Not for consideration In stable geological mSv/yr formations

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 157  0DQDJHPHQWRI///,/:

Ukrainian regulations ND306.607.95 and GN666.054.2000 specify the design principles for long-lived and high level wastes. In accordance with ND306.607.95, ‘Requirement for SRW Management Prior to Disposal’, radwaste management approach must comply with the programme that is agreed with the regulatory bodies. This programme will take into account the following factors:

• Availability and suitability of technical equipment and technologies that meet the modern technologies; • SRW classification requirements for packages (types, physical characteristics, chemical composition, volumes and radionuclide composition), • Availability of facilities for SRW storage/disposal, and SRW acceptance criteria for storage/disposal; • Need for auxiliary equipment and facilities during decommissioning; • Appropriate financial requirements and administrative procedures, • System of registration and document circulation required for SRW inventory; • Availability of certified personnel; • Gained experience and necessity for further research and development.

In the process of designing the SRW management facilities, the design criteria are to include the limits and boundaries for normal operation of the facility, including the requirements to SRW, limits for treatment factors, safety and quality assurance, and requirements for maintenance, testing, and monitoring. During the process of designing the facilities for SRW that can contain fissile material, it is obligatory to take into account the requirement of criticality prevention.

In designing the facilities for the long-term storage of conditioned SRW, the following factors will be specifically reviewed:

• Integrity of packages of SRW within the designated storage period, and measures which allow for possible depressurisation • Possible usage of remote controlling devices; controls to eliminate the personnel exposure to irradiation; • Recording, registration, and secure identification of SRW subject to storage; • Environmental impact of the safety and security of the SRW storage; • Need for auxiliary ventilation systems, cooling systems, etc., while storing the specific categories of wastes.

Procedure for the retrieval of wastes from the Exclusion Zone is described further.

The majority of dumps contain both organic and inorganic wastes, which differ in their nuclide composition and activity. In order to decide on a method for the further management of retrieved SRW, it is necessary to sort the waste according to:

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 158 A. The types of subsequent treatment, as determined by physical and chemical characteristics; B. The content of nuclear hazardous fissionable materials; C. The level of specific activity and the level of surface contamination; D. Aggregate state (solid wastes, liquid wastes); E. Short-lived and long-lived wastes.

The groups A and B determine the technologies of the SRW management, groups C and D define the requirements for nuclear and radiation safety, group E specifies the method of final disposal.

The activity is controlled with the aid of passive gamma monitoring by scanning the surface of the construction under investigation. SRW characterisation according to physical parameters is carried out to identify the method of further SRW treatment.

Waste will also be sorted into the groups for compaction and incineration. The criteria for this are given in Section 5.2.3.

Small fractions of solid LL-LILW (earth, sand, road metal, small pierces of metal, wood, concrete, etc.) are put into 200 l drums which in turn are put into reusable containers and transported to CTD for final treatment and storage.

Large and long units of SRW are identified by visual inspection and isolated as soon as the radioactive wastes are retrieved from a dump. Usually they have surface contamination and are processed in their own right. After fragmentation, the wastes are put into 200 l reusable drums (LL LILW) and transported to the CTD.

Radiation monitoring is carried out during the removal of SRW. The removal activities are performed with the aid of special equipment with remote control and telemonitoring as appropriate.

The management technology for radwaste from the Unit Shelter site is characterised as follows:

Radionuclides in theman-madelayer of the Industrial Zone of ChNPP tend to migrate into the soil as a result of disintegration of the matrix, which contains them. Under these circumstances, the radical way to prevent the environment from contamination with the radioactive substances located in the man-made layer can be its total removal. To develop projects and technologies to do the required work is a complicated scientific, technical and engineering problem. It is explained by the fact that when removing the man-made layer, which is quite thick and varies in its composition, in high radiation field environment, it raises the issue of interim storage facilities and disposal of a huge amount of the emerging radwaste of all groups,

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 159 including those containing long-lived transuranium elements and reactor core fragments.

Project to remove the man-made layer should provide for the following:

• to prepare a working area; • to remove the man-made layer; • sorting of emerging radwaste into contamination groups and categories; • conditioning by containerisation; • radiometric assessment; • Producing certificates for containers with radwaste; • transportation of radwastes for disposal (SL-LILW) • transportation of radwastes for long-term interim storage (HLW according to the Ukrainian categorisation and LL-LILW/HLW according to IAEA classification);

The feasibility study into the establishment of the facility for radwaste treatment and disposal in the framework of the project ‘Vector’ provides for initial radwaste sorting in the areas where it emerged and its final sorting in CTD. The initial sorting should be done in such a way that sorted waste meet the requirements of the disposal points or interim storage facilities.

Radwaste sorted into groups and categories is put into appropriate initial packages or shielding containers. Radiometric assessment is to be conducted and certificates for radwaste are to be issued. Filled containers or initial packages are put into shipping packing containers and delivered to interim storage facility or for final disposal. Thus, radwaste delivered from the site is packed so that it can be further stored or buried.

LL SRW and HLW that were sorted and certified are shipped to CTD, where the acceptance inspection of radwastes is carried out and the operation-routine sequence for the radwaste management process is specified.

Waste acceptance

The technological operations related to the management of radioactive wastes performed by specialised organisations is preceded by the operations associated with inspection and inventory of SRW subject to treatment and subsequent disposal, storage. The goal of this waste acceptance is to confirm the fact that accepted wastes meet the design requirements established by organisation and published data of a package correspond to the wastes and objectively measured parameters. CTD waste acceptance system should be supplied with an automated system for radiation parameter control. It should provide means for identifying the content of long-lived and transuranium radionuclides and make it possible to perform the selective sampling in CTD. However, the Supplier should fill in the certificate and meet the CTD requirements to waste acceptance.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 160 Treatment The possibilities to treat LL-LILW are limited by the limits for incineration and compacting.

For incineration the specific activity of raw waste should fall into specific activity levels corresponding to IAEA SL LILW category.

• 3700 Bq/g, for β- activity • 370 Bq/g, for α - activity.

The dose rate of SRW subject to compressing should be less than 0.5 µSv/hour at the distance of 10 cm from the package. However, according to the agreement with the Ministry of Health, it is possible to compress the waste of higher dose rate on condition that the limit of the personnel dose rate would be not more than 20 mSv/year. It is planned that CTD will have protected compressing equipment supplied with remote control devices, which will make it possible to compress the wastes with the dose rate up to 10 µSv/hour. These methods can be effectively used for treatment of metallic waste. It was evaluated that the amounts of compactible LL-LILW are too small to cause modifications of the planned compaction facility.

Interim storage

Following requirements should be considered in the design of the storage facility for LL- LILW and HLW:

• Storage facility must have an area for receipt and unloading of transportation containers with the remote control systems. • Storage facility should be equipped with transportation means with remote control systems to provide the address delivery of containers. • Storage facilities should be divided into compartments, which have different degrees of protection depending on the type of waste and the design of containers. • Storage facility should be divided into clean and contaminated areas and have waste assessment room. • Storage facility should have decontamination and repair area. • Storage facility should have the radiation protection system that meets the requirements of Ukrainian regulations.

The most part of LL-LILW is packaged into 200 l drums. Following the requirements of regulations 306.608.95, the containers for SSRW disposal should provide ionising radiation protection so that the dose rate at the distance of 1 m is less than 0.5 µSv/h. Under these conditions, the drums can be immediately delivered to the near-surface NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 161 storage facility. In the case that the dose rate is more than 0.5 µSv/h, the wastes should put into reinforced-concrete containers of KZNP-2.1 or KZNP-6.5 types.

The SRW-3 repository type is planned for long-term interim storage of LL-LILW.

The storage facility walls are made of concrete blocks, which are 600 mm thick. Walls, which divide the storage facility into vaults, are made of reinforced-concrete solid blocks, which are 100 mm thick. The lid will be made of lightweight metal constructions manufactured by the Zhitomir plant for a building with dimensions of 24×42m. The gates will be mounted in the course of laying the sections. Drainage of surface waters will be ensured. The interior surface of walls will be protected from water by bitumen (2 layers) and will have clay along the borders. Altogether, 22,060 waste containers will be stored in the 15 vaults of this facility, which is equivalent to 4,412 m3 of waste.

Concrete containers will be placed into appropriate vaults of the SRW-3 facility. Filled sections will be covered by concrete slabs and sealed.

Recommended acceptance criteria for the CTD

5DGLRQXFOLGHFRPSRVLWLRQ Packaged SRW must be delivered classified by their radionuclide composition. SRW consignment certificate should be executed in accordance with SPORO-85.

6SHFLILFDFWLYLW\ Maximum permissible activity of radionuclides is accepted consistent with the requirements to the waste transportation safety in transporting packages of A type. The concentration of fissionable nuclear materials in one A-type package must not exceed 15 grams. In specific cases upon concurrence with the regulatory bodies it is permitted to accept wastes with the specific activity that exceeds these requirements. In this case, SRW must be shipped in B-type packages (unlimited activity), in this case the concentration of fissionable nuclear materials in one B-type package must not exceed 300 grams.

6XUIDFHFRQWDPLQDWLRQ Surface contamination of radioactive waste packages must not exceed

• Alpha-active materials – 10 particles / cm2 min • Beta – active materials - 400 particles/ cm2 min

6WUXFWXUDOVWDELOLW\ During shipment activities it is necessary to provide physical integrity of packages. The stability is to ensure that the personnel irradiation will not exceed the admissible levels.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 162 Leaching is determined by the project so that radionuclide emissions do not exceed the safety levels.

7KHUPDOHIIHFW Design of the waste packages for intermediate level waste with the heat generation up to 2 kW/m3 as well as their quantity in one package must ensure that waste temperature does not exceed 300 C, in case of absence of forced cooling. This issue must be clarified when designing the repository.

)LUHVDIHW\ Wastes combustibility should be low enough not to cause self-incineration of waste packages. Combustible waste must be shipped separately from other types of wastes.

*DVIRUPDWLRQ It should not cause pressure boost in the encapsulated package containing wastes for disposal.

)UHHOLTXLGV Packages with radioactive materials subject to disposal must not contain visually observed free liquids.

([SORVLYHDQGVHOILQIODPPDEOHPDWHULDOV Wastes containing explosive and self-inflammable materials are not accepted

3DFNDJHUHVLVWDQFHWRFRUURVLYHDWWDFN Containers with SRW subject to disposal in the near-surface storage facilities must have 300-year service life. Containers for radioactive wastes subject to storage in near-surface storage facilities must have 30-year service life (it is the recommended term of storage that must be concurred with the regulatory bodies). Resistance to corrosion of container material is determined consistent with these requirements. Transporting packages used to ship wastes for treatment are to be made of materials that are resistant to corrosion during the package service life.

1XFOHDUVDIHW\ The content of fissionable materials in the package should be safe not to cause criticality (see requirements to Criterion ‘Specific activity').

3DFNDJHODEHOOLQJDQGLGHQWLILFDWLRQ Packages with SRW must be easily identified during the wastes acceptance, during SRW management at specialised enterprises within full term of storage (30 years) and during the active operation period of the disposal repository till the repository’s preservation.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 163  8SGDWHGZDVWHLQYHQWRU\DQGLQYHQWRU\FRPSDULVRQ

Details of the waste inventory for the Chernobyl Exclusion Zone, including the Chernobyl Industrial Site, are provided in the Section 3. In Section 4 the need to retrieve the wastes from each site was assessed. Resulting estimates are provided in Table 60 and Table 61 for long-lived and short-lived wastes respectively (IAEA). It has been estimated that in total some 600,000 m3 of radwastes will have to be retrieved from the Exclusion Zone.

  5HWULHYDO &RQVW 5HDFWRU &RQFUHWH 6DQG6RLO 0HWDOP ZRRG 2WKHUP UXFWLRQ  &RUH EULFNP P URWWHG  ZDVWHP IUDJPHQWV ZRRGP P $6$3 0.00E+00 1.70E+03 2.13E+03 3.75E+03 3.27E+02 4.22E+02 0.00E+00 FDWHJRU\$ (YHQWXDO 6.00E+00 0.00E+00 2.00E+03 2.05E+03 3.15E+01 0.00E+00 1.70E+01 UHWULHYDO FDWHJRU\% 7RWDO 6.00E+00 1.70E+03 4.13E+03 5.80E+03 3.58E+02 4.22E+02 1.70E+01 7DEOH(VWLPDWHVRIZDVWHVWUHDPYROXPHVIURPWKH([FOXVLRQ=RQHIRU// /,/:

  5HWULHYDO &RQFUHWH EULFN 6DQG6RLOP 0HWDOP ZRRG  URWWHG P ZRRGP $6$3 2.43E+05 3.27E+05 2.10E+04 6.99E+03 FDWHJRU\$ (YHQWXDO 4.80E+03 0.00E+00 4.19E+03 0.00E+00 UHWULHYDO FDWHJRU\% 7RWDO 2.48E+05 3.27E+05 2.52E+04 6.99E+03 7DEOH(VWLPDWHVRIZDVWHVWUHDPYROXPHVIURPWKH([FOXVLRQ=RQHIRU6/ /,/:

As detailed in Section 4, these estimates take into account retrieval from the following locations:

- Industrial Zone – all wastes, which are within the scope of the current study (excludes HLW in the vicinity of the Shelter), in line with the schedule of construction on the territory of the Industrial Zone - PZRO Podlesny – all long-lived wastes (category B) - PZRO Buryakovka – all long-lived wastes and machinery (category B) - PZRO Kompleksny – all wastes - PVLRO Stroybaza – wastes from the area designated for construction and all long-lived wastes - PVLRO Ryzhy Les – all long-lived wastes

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 164 Estimates of long-lived waste arisings from each of these sites are provided in Table 63.

Based on these estimates, the volumes of waste streams can be estimated as shown in *Includes reactor fragments from the Pioneer Wall location, which is outside the scope of the current study

Table 62. It can be seen that according to the current estimate, volumes are dominated by the arisings from the Industrial Zone.

,QFLQHUDWLRQ &RPSDFWLRQ 2WKHU Previous estimates Industrial Zone 2.00E+02 5.00E+03 4.62E+05 Exclusion Zone outside Industrial Zone 4.00E+05 3.00E+04 1.02E+06 7RWDOSUHYLRXVHVWLPDWH ( ( ( Current study Industrial Zone 0 1.70E+03 4.36E+05 LL-LILW 4.22E+02 2.06E+03* 9.96E+03 7RWDOFXUUHQWVWXG\ ( ( ( *Includes reactor fragments from the Pioneer Wall location, which is outside the scope of the current study

 7DEOH:DVWHVWUHDPYROXPHHVWLPDWHVP

In the current study it was assumed that only wood and rotted wood will be subjected to incineration and that only metals will be subjected to compaction. Current estimates, as well as previous data suggest that the majority of wastes will be encapsulated without volume reduction. All volumes are judged to be significantly lower than previously estimated, however, the following considerations should be taken into account:

- Waste stream volumes for the Industrial Zone have not been modified compared to the previous values. - It will be necessary to incinerate contaminated vegetation, growing over the dumps. This has not been considered in the current study - It is assumed that waste arisings from Rassoha and other unsanctioned dumps will be disposed at Buryakovka. - Following risk assessment it is possible that a number of further dumps will be identified for the retrieval of waste (presently category C). For example if it is judged that soil, which exceeds free release levels as well as all other dumps should be removed from the current location, total waste arisings would exceed 21,000,000 m3, which is a much higher value than it will be feasible to safely process and dispose.

However, it is judged unlikely that eventual arisings of long-lived wastes from sites considered within the current study will be higher than those given in Table 62.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 165 Area Earlier estimations/CTD-conception Inventory according to this study

LL-LILW Waste composition LL-LILW Waste composition Volume, m3 Volume m3 Buryakovka * * 150 concrete, bricks, sand, soil, metal, others Podlesny * * 3,960 Graphite, core construction debris, concrete bricks, sand, soil Ryzhy Les 695 Rotted wood, soil 626 sand, soil, rotted wood Staraya Stroybaza - - 2,178 Concrete, bricks, sand, soil, metal, rotted wood Exclusion Zone 2,675 Concrete, sand, crushed 5,525 Reactor core fragments, concrete bricks, sand soil stones, Stantziya Yanov 226 Metal, Rotted wood, 0- concrete bricks, soil Peschanoye Plateau 630 soil 0 Neftebaza 3,965 Metal, rotted wood, 0- concrete bricks, soil Total 8,191 12,439 *) Waste has not been taken into account, as waste to be disposed at CTD

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG 166  ,PSOLFDWLRQVIRUPDQDJHPHQWRIORQJOLYHGZDVWHV

The main implications for the waste management at the Chernobyl Exclusion Zone resulting from the updated LL-LILW waste streams are discussed in the following sections. They take into account the close connection of LL-LILW management with the general waste management system. In general the management process include the following steps:

• Preparation of the working area • Opening of storage trenches and buildings • Removal of the waste • Sorting emerging radwaste into contamination groups and categories, • Treatment, and containerisation • Transport to CTD • Conditioning • Disposal of SL-LILW or long-term storage (HLW, LL-LILW) in accordance with the Ukrainian standards following IAEA recommendations.

All steps are accompanied by necessary radiological measurements and prove by documents.

 5HPRYDOVRUWLQJFRQWDLQHULVDWLRQDQGWUDQVSRUW The necessity to retrieve the waste from the different sites is discussed in Section 4 based on a risk assessment.

Methods and techniques of opening, removing, sorting and treatment depend mainly on the following factors:

• Storage conditions at the different sites • Waste characteristics

The order of waste removing depends on

• Readiness of CTD to accept LL-LILW • Risk assessment of the different storage sites • Interactions with other activities at the sites

Using of remote controlled techniques for opening, removal, treatment and containerisation will be necessary on a large scale.

It is of great importance to ensure efficient radioactive waste sorting, taking into account the contamination diversity and the random distribution of radionuclides in the waste. The CTD conception in the framework of the project ‘Vector’ provides for initial waste sorting at the storage sites and final sorting at the facility. Initial sorting should separate waste streams for disposal or interim storage. Efficient initial sorting is important since the costs associated with the interim storage and final disposal of

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 167 long-lived and high-level waste significantly exceed those associated with the disposal of short-lived LILW.

Following sorting and necessary treatment, each radwaste group will be placed into appropriate containers. An evaluation of existing containers relating to suitability for transport, interim storage and disposal and requirements for new waste and transport containers has been performed by OSAT [OSAT, 1999b]. According to this OSAT report different container types suitable for transport and long-term storage of LL- LILW will be available. The necessary larger number of such containers owing to the larger volume of LL-LILW is the only a part of the problem to ensure needed production rates of potential Ukrainian container suppliers.

Based on the current information on provided methods and techniques of removal, sorting and transport can be made the conclusion, that there is not a necessary for qualitative changes due to the larger volume of LL-LILW.

 7UHDWPHQWDQGFRQGLWLRQLQJ The following technologies for treatment and conditioning are provided at the CTD:

• Incineration • Compaction • Cementation

Incineration

According to the Report inventory data there are in total some 420 m3 of combustible LL-LILW. These waste, wood and rotted wood, are located at the PVLRO Ryzhy Les and Staraya Stroybaza.

Incineration of LL-LILW is executed in Western European countries. For example, there is an experience of the Karlsruhe Nuclear Research Centre [Baehr, et al, 1984] on incineration of long-lived solid waste with an specific α-activity in the range of < 5×107 Bq/m3 up to < 5×1010 Bq/m3. Waste with a specific α-activity < 5×107 Bq/m3 is incinerated in a pit furnace provided with a secondary combustion chamber. Waste with a higher specific α-activity up to 5×1010 Bq/m3 is incinerated in a special incineration plant. The incineration facilities are provided with separate flue gas cleaning sections, which include hot gas filtering candles, scrubber systems and HEPA filters.

In such a way it is technically possible to incinerate all combustible LL-LILW waste from the above mentioned two sites within the Chernobyl Exclusion Zone. But for CPD incinerator it is specified that α-activity should not exceed 370Bq/g. This value is comparable to the IAEA activity limit of LL-LILW of 400 Bq/g. Subsequently, according to the Ukrainian regulatory requirements, incineration of LL-LILW is not allowed.

According to the IAEA recommendation concerning waste acceptance criteria for disposal [IAEA 1985, IAEA 1990, IAEA 1996] radioactive waste should meet among others the following requirements:

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 168 • The waste should contain as little free liquid as possible. • The presence of organic material in waste packages should be limited in order to control microbial degradation and gas production. Waste should not ferment or rot. • Gas generation in the waste package should be such that the performance of the disposal system is not compromised. • The combustibility of the waste form or waste package should be such that the potential for fire is as low as reasonably achievable.

Similar requirements exist in Western European countries to waste to be disposed of [BNFL, 1999; Konrad, 1995; Basic Safety Regulations, 1984]. For example, the waste acceptance criteria of the Drigg repository (UK) [BNFL, 1999] limit the content of waste liable to be decomposed by micro-organisms of maximum 5% by weight of any consignment. The recommended LL-LILW waste acceptance criteria for the CTD also contains such requirements.

Exclusion of combustible LL-LILW from incineration waste stream creates potential problems. Treatment and conditioning methods as compacting or cementation can not prevent problems resulting from the relatively high water content and the high potential danger of gas generation and microbial degradation of this waste.

A possible way to deal with the combustible LL-LILW from the PVLRO Ryzhy Les and Staraya Stroybaza could be to mix LL-LILW waste with combustible waste of low activity to bring α-activity concentration of the mixed waste to levels acceptable for incineration at the specified facility. Such method requires constructing a special mixing facility. Requirements to the waste for incineration, such as limits on humidity (40%) and content of non-combustible mineral impurities (1%), should be taken into account. A preliminary drying the waste should be considered, if the humidity exceeds the mentioned limit. The volume of this mixed waste to incinerate is less than 1 % of total combustible waste from the Chernobyl Exclusion Zone and does not have any significant impact on the planned incineration capacity.

Compaction

This technology is mainly used for volume reduction of metallic waste. But, other waste categories, as foils, bags, filters, wipes, bottles, clothing, cans, tools, small apparatus, glassware, can be compacted also.

The inventory data of the Report shows a total volume of metallic LL-LILW of approximately 2000 m3. This metallic waste, cut and packaged in container, can in principle be compacted at the CTD compaction facility. The only compaction facility acceptance criterion is that the dose rate should not exceed 0.5 mSv/hour at the distance of 10 cm. As mentioned earlier, according to the agreement with the Ministry of Health, it is possible to compress the waste of higher dose rate on condition that the limit of the personnel dose rate would be not more than 20 mSv/year. It is planned that CTD will have protected compressing equipment supplied with remote control devices, which will make it possible to compress the wastes with the dose rate up to 10 mSv/hour. So, the compaction facility can be used for compaction of LL-LILW waste.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 169 The total volume of LL-LILW suitable for compaction is very small compared with the total volume of metallic waste and has no impact on the compaction facility. It is possible that some of the other waste streams, not presently designated for this treatment, can also subjected to compaction.

Immobilisation

There is a wide range of potential matrix materials used for the immobilisation of waste with considerable content of alpha-emitters. The selection of a specific immobilisation process is dependent on the waste treatment stage and the subsequent handling, transport, storage and disposal requirements. However, the overall objectives of immobilisation [IAEA, 1991] are to produce:

• Waste forms with sufficient mechanical, physical and chemical stability to satisfy all stages of handling, transport and storage, and • Waste forms, which will satisfy disposal requirements and inhibit the release of radionuclides to the biosphere.

In the case of LL-LILW from the Chernobyl Exclusion Zone should be taken into account, that the long-term storage at the surface is planned until an underground repository will be available. This fact justifies a particular attention to the waste form in respect to the long-term safety (about 50 years). Thus the method and degree of immobilisation should be defined based on a safety assessment of the long-term storage at the CTD facility.

Taking into account the experience of western Europe countries in the management of long-lived waste and the conception of the CTD the following fundamental principles could be used for immobilisation of such waste:

• Storage of LL-LILW is performed only in containers. Large pieces are to cut and packaged into containers;

• Concrete bricks, metallic pieces, which can not compacted, mixed scrap, shredded organic waste particles, and similar waste forms, should be packaged into containers and embedded into cement;

• Sand and soil should be packaged into containers and the residual container volume should be filled with cement to an attainable level. The water content in soil and content of materials, which can cause microbial degradation and gas production in soils, is to take into account. Soil should be checked relating to the combustibility. Combustible soil should be sorted out and incinerated.

• Ashes from incineration should be cemented

The planned waste management and the CTD conception allows to perform listed operations.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 170  ,QWHULPVWRUDJHRIORQJOLYHGZDVWHV The main requirements to the long-term interim storage of LL-LILW/HLW at the CTD are explained in section 5.2.5. The likely eventual requirements on the capacity of CDT long-lived waste storage facility (SRW-3) due to these wastes are likely to be within 12,000 m3 (see Table 60 and Table 62). In the short to medium term these should not exceed 8,000 m3 (category A only, excluding long-lived wastes from Buryakovka and Podlesny). In such a way all long-lived wastes from the areas of Exclusion Zone, considered within the current study, are likely to be contained within a single SRW-3 type store of specified capacity (13,000 m3, see Table 57).

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 171  &RQFOXVLRQVDQGUHFRPPHQGDWLRQV  &RQFOXVLRQV .H\ILQGLQJV

In the present conditions none of the dumps satisfy international guidelines for near- surface waste disposal. However, for some of the dumps, following the performance of risk assessments and the implementation of countermeasures, disposal may be feasible in situ.

Based on a review of the literature and performance of preliminary calculations of the doses to critical groups undertaken within the current study, it is concluded that

• At the present time, the highest potential doses to site operators or the public result from the occasional ingestion of contaminated animals, birds or plants (mushrooms and berries) which have been in direct contact with contamination. External exposure is another factor, which contributes significantly to doses at contaminated sites.

• Human intrusion, although unlikely in the present conditions, represents a significant long-term risk for dumps containing long-lived wastes, which would not decay to acceptable levels after the period of institutional control.

• There is no indication that either the groundwater or atmospheric dispersion pathways are likely to result in doses above the ICRP-recommended constraint of 0.3 mSv/yr from a single source. One notable exception is doses to firemen, resulting from the inhalation of radioactive smoke in the event of a forest/bush fire over the dumps, which may exceed the above constraint. However, these doses would be significantly reduced if protective equipment were to be used. In addition, doses greater than the ICRP constraint may be received as a result of the ingestion of contaminated groundwater. These would be significantly reduced if access to the groundwater could be prevented.

Based on the available data, long-lived wastes (IAEA classification) are present in the following locations:

• Industrial Zone (~1% of all considered wastes are long-lived) • PZRO Podlesny (100%) • PZRO Buryakovka (~0.03%) • PVLRO Ryzhy Les (~0.5%) • PVLRO Staraya Stroybaza (~0.5%)

According to the available information, heat-generating wastes are only present in the vicinity of the Shelter outside the area covered by the current study.

The estimated waste stream volumes, for which retrieval and subsequent treatment are required, are as follows:

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 172 • Incineration – 7,500 m3, including 450 m3 of long-lived wastes • Compaction – 28,000 m3, including 2,100 m3 of long-lived wastes. A large proportion of these long-lived wastes originated from the Pioneer Wall containers (1700 m3) and as such is outside the scope of this project. • Storage in near-surface facilities – 10,000 m3 of long-lived wastes • Disposal in near-surface facilities – 600,000 m3 of short-lived wastes

If wastes were to be retrieved from some of the PVLROs currently identified for further study (category C), the above estimates would increase. For example, the retrieval of wastes from Sectors 5.1 (PVLRO Neftebaza), 2.1 (Ryzhy Les) and 3.5 (Stantziya Yanov), which are partially flooded by surface water (either continuously or periodically), would generate a further 400,000 m3 of short-lived wastes.

Previous estimates of the waste streams for retrieval and subsequent treatment were significantly higher (400,000 m3, 35,000 m3 and 1,500,000 m3 for incineration, compaction and other treatment, respectively). The reasons for the discrepancy are outlined below.

The planned waste management concept for the Complex for the Treatment and Disposal of Wastes (CTD, also referred to as Vector) generally complies with the requirements resulting from the updated waste streams. From the available information it is judged that the throughput of the incineration and compaction facilities will be adequate to process considered waste arisings from the Exclusion Zone. The current specification of the incinerator does not allow processing of long- lived wastes and thus presents a potential problem.

The planned disposal capacity for short-lived wastes was estimated to be excessive, but only if waste is not retrieved from the dumps currently identified for future risk assessment. It should be noted that the present degree of uncertainty is such that it is possible that the currently planned disposal capacity for short-lived wastes may actually prove too small. This will depend on whether the disposal in some of the existing dumps can satisfy Ukrainian operational and post-closure individual dose constraints.

Required storage capacity for long-lived wastes, which has not been previously assessed, was estimated to be within the limit of a single SRW-3 type store with the capacity of 13,000 m3.

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There is an urgent need to introduce a waste classification system that is consistent with the IAEA approach, which is generally accepted by the Ukrainian authorities.

PZRO Buryakovka, which in general satisfies the basic IAEA guidelines for near- surface disposal, was found to contain some long-lived waste. This differs from the previous assessments of waste in the Exclusion Zone The existing waste acceptance criteria at Buryakovka currently allow wastes with specific α-activities which exceed the IAEA criterion for long-lived waste of 400 Bq/g of α-activity.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 173 'LIIHUHQFHVZLWKSUHYLRXVDVVHVVPHQWV

Significant volumes of contaminated soil located within the Exclusion Zone, which were not considered previously, should be categorised as radioactive waste. Although the previous estimates of the waste volumes, which will have to be managed at Vector facilities, were based on the assumption that all radioactive wastes from the Exclusion Zone will have to be retrieved, they failed to take into account some 20 million m3 of contaminated soil.

The estimates of the waste inventories within the radioactive dumps need to take into account the waste content of the top-soil layer. In some cases, this leads to double the estimated waste volume.

It was found that the existing inventories do not take into account radioactive decay and ingrowth since the date of measurement. This relates to the database, developed within the project TAREG 029 and a slightly modified version used by OSAT, as well as to the annually reviewed inventories of various sites, supported by SSE Complex. The neglect of radioactive decay led to a significant overestimation of the overall inventory, equivalent to more than two orders of magnitude, between the years 1986 and 2000 for the Unit 4 fuel composition, primarily due to decay of short-lived radionuclides in 1980s. Over the last decade the activity approximately halved. At the same time, the presence and ingrowth of some important radionuclides had been neglected. This relates primarily to 241Am, which is the decay product of 241Pu, and to 238Pu. These radionuclides are present in significant concentrations. At present 241Pu is responsible for approximately 20% of the overall activity, while 241Am and 238Pu are responsible for 45% and 15% of the total α-activity, respectively.

The inventory of PZRO Podlesny has been significantly overestimated in recent studies. One assessment provided activity values comparable to the total activity released during the accident and in excess of the radioactivity fallout beyond the boundaries of the Industrial Zone. Further errors and inconsistencies in previous inventory estimates were identified for PZROs Kompleksny and Buryakovka.

Both previous and current estimates of waste volumes for incineration and compaction are small compared to the overall volumes of waste. The principal difference in the total volumes results from the differing approaches relating to the need for waste retrieval. While the retrieval of all wastes (assumed previously) is judged to be impossible due to the unmanageable volumes involved, it is feasible that current estimates may increase in the future. In particular it may be necessary to retrieve waste from some of the dumps which have been categorised as group C (further assessment required). A decision should be taken on the basis of the acceptability of risk, the cost and benefits of implementing in-situ countermeasures and the cost and radiological safety issues associated with waste retrieval and subsequent management.

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The majority of wastes in the Exclusion Zone have not been characterised. In a number of cases, the general lack of inventory data leads to unacceptable uncertainty

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 174 in the quality of estimates. The sites, for which inventory data do not amount to more than an educated guess, are listed below:

• Industrial Zone outside Shelter Local Zone • PZRO Podlesny (and to a lesser degree Kompleksny) • Sectors 2.2-2.6 (PVLRO Ryzhy Les) • Sectors 3.2-3.4, 3.6, 3.7 (PVLRO Stantziya Yanov) • Sectors 1.1-1.4 (PVLRO Staraya Stroybaza) • Sector 1.5 (PVLRO Novaya Stroybaza). • PVLROs Kopachi, Chistogalovka, Pripyat and Stantziya Semihody • Rassoha 1 and 2 • ‘Unauthorised’ disposal sites • Contaminated trees and bushes

The lack of a post-closure risk assessment for any of the dumps means that, at the present time, it is impossible to make a judgement on whether some of the facilities will fully comply with the Ukrainian or international regulations following implementation of the countermeasures.

 5HFRPPHQGDWLRQV 5HJXODWRU\LVVXHV

It is necessary to complete the process of bringing the Ukrainian waste categorisation system in line with IAEA guidelines.

With disposal at Buryakovka still on-going, there is an urgent need to modify the existing acceptance criteria so that wastes with specific α-activity above 400Bq/g cannot be disposed in the near-surface trenches.

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There is a need to characterise the waste in those locations where a lack of data results in unacceptable uncertainty (see above).

The assessment of doses is required to identify the need for retrieval, when disposal conditions are not in obvious contradiction to the basic disposal guidelines (e.g. in the case of long-lived waste) or are not justified by the need for construction work. The assessment should verify compliance (or not) with the regulatory dose constraints for the institutional and post-institutional control periods.

Risk and safety assessments are also required for those sites where the retrieval of waste is recommended, including

• the interim storage period • doses incurred during the waste handling operations

Areas within PVLROs Neftebaza, Ryzhy Les, Stantziya Yanov and a significant proportion of contaminated soil, which are permanently or seasonally flooded by surface water, represent an area of particular concern. This is because it may be

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 175 difficult to isolate these dumps from the biosphere. Exposure via the ingestion of water-nesting fowl (e.g. ducks) deserves special attention.

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Wastes must be retrieved from the following sites:

• Industrial Zone – in line with the schedule of construction of a new sarcophagus • PZRO Podlesny – prior to termination of institutional control • PZRO Buryakovka (long-lived and machinery only) – before the end of institutional control • PZRO Kompleksny – as soon as possible • PVRLO Ryzhy Les (long-lived only) – as soon as possible • PVLRO Staraya Stroybaza (area affected by construction and long-lived waste) • Unauthorised dumps, including Rassoha – as soon as possible

For the remaining dumps, vegetation at the surface should be removed. The dumps should be fenced and capped to ensure isolation from the biosphere and to decrease the risk of human intrusion. Fortification of the structure for PZRO Podlesny must be undertaken to ensure the safe storage of long-lived wastes in situ in the short-term. Whenever possible, measures, such as construction of flood defenses, should be undertaken to remove flooding of the dumps and contaminated soil.

It is necessary to verify the presence of combustible long-lived wastes in the dumps. An additional facility for mixing combustible LL-LILW waste with waste of a low activity containing only insignificant amounts of long-lived waste, with the aim to decrease the activity level of the mixed waste below 370 Bq/g, should be considered. In this way mixed waste could be incinerated at the planned incineration facility at the CTD in accordance with the Ukrainian safety requirements.

Immobilisation methods, such as the cementation of ashes and embedding into cement, suitable to prevent radionuclide migration during normal operation and in the event of accidents, should be considered. The methods and degree of LL-LILW immobilisation should be based on a safety assessment of the long-term storage at the CTD facility.

All long-lived wastes from the areas of the Exclusion Zone, considered within the current study, are likely to be contained within a single SRW-3 type store of specified capacity (13,000 m3).

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 176  5HIHUHQFHV 1. Antropov V M, Budai D A (ed) (2000a). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Summary of information on PZRO Buryakovka. Kiev.

2. Antropov V M, Ledenev A I, Ovcharov P A, Budai D A (ed) (2000b). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Summary of information on PZRO Podlesny. Kiev.

3. Aronov V.I. (1990). Computational mapping methods for geological and geophysical indicators and sealing of oil and gas resources. Moscow, Nedra (in Russian).

4. Baehr, W. W., Hochlein, et al (1984) „Experience and projects for treatment and conditioning of all wastes from reprocessing plants in the Federal Republic of Germany“, Radioactive waste management, Proceedings, Intern. Conference Seattle 1983, Vol.2, IAEA, Vienna

5. Basic Safety Regulation No. 1.2 (1984). Safety Objectives and Basic Design for Surface Centres for Long Term Storage of Solid Radioactive Waste with Short or Medium Half Live and Low or Intermediate Activity. SIN No. 3210/84, June 1984.

6. Belyaev S.T., Borovoi A.A., Buzolokov U.P. et al (1990) Some aspects of post- accident work in the conrolled area of Chernobyl NPP. Proceedings of an International Symposium on Recovery operations in the Event of a Nuclear Accident or Radiological Emergency organized by International Atomic Energy Agency and held in Vienna, 6-10 November 1989. IAEA-SM-316/42. IAEA, Vienna.

7. Berkovski V G, Ratia, Nasvit O (1996) Internal doses to Ukrainian populations using Dnieper River Water, Health Physics, 71 (1), 1996, pp37-44

8. BNFL, 1999. BNFL Conditions for Acceptance by BNFL of Radioactive Waste for Disposal at DRIGG. (CFA, Issue 99/1)

9. Borovoi A.A., Sich A.R. (1995) The Chernobyl Accident revisited, Part II: The state of the nuclear fuel located within the Chernobyl Sarcophagus. Nuclear Safety, vol.36, no.1.

10. Bugai DA et al (1996) Risks from radionuclide migration to groundwater in the Chernobyl 30km Zone. Health Physics, 1996, Vol 71, 1, pp9-18.

11. Bugai D.A. (2000) Risk assessment information. IGS.

12. Bugai D A (ed), Antropov V M, Ledenev A I, Ovcharov P A (2000a). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 177 Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Estimates of volumes and characteristics of waste within the unsurveyed PVLRO within the Near Zone of ChNPP. Kiev.

13. Bugai D A, Dzhepo S.P. (2000b). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Information on the assessment of risks and prioritisation of the radwaste dumps in the Chernobyl Exclusion Zone. Part I Kiev.

14. Chernobylinterform (1996) “Chernobyl, ten years of disaster consequences elimination”, edited by V. I. Holosha, Chernobylinterinform

15. David M. (1980) – Geostatical methods for estimating ore reserves. Moscow, Nedra (in Russian).

16. DGXI (1998) Characterisation of waste and contaminated material which will be produced during the construction of a new sarcophagus around Chernobyl reactor No.4, Contract No B7-5200/97/000077/MAR/C3.

17. Draft of National Standard of the Ukraine (1999) Classification of radioactive wastes. Derzhstadard of the Ukraine, Kiev (in Ukrainian).

18. Dzepo S.P. (1996) Current and future estimates of radiological conditions in the Exclusion Zone and development of recommendations to improve monitoring of groundwater. IGS, 1996

19. Energoproekt (1995). Working Design. PZRO Podlesny. Sealing. Energoproekt. Kiev (in Russian).

20. GNPO Metrologia (1998). Methodology for measuring characteristics of SRW at PZRO Buryakovka. GNP Metrologiya (in Ukrainian).

21. Holosha V, Proskura V, Ivanov Yu et al (1999) Radiological and ecological significance of natural and technological sources in the Exclusion Zone. Bulletin of the ecological state of the Exclusion Zone and evacuation of population No 13 pp3-8.

22. IAEA (1985). Acceptance Criteria for Disposal of Radioactive Wastes in Shallow Ground and Rock Cavities. IAEA Safety Series No 71, 1985.

23. IAEA (1990). Qualitative Acceptance Criteria for Radioactive Wastes to be Disposed of in Deep Geological Formations. IAEA-TECDOC-560. Vienna.

24. IAEA (1991). Conditioning of Alpha Bearing Wastes, Technical Report Series n° 326, IAEA, Vienna, 1991

25. IAEA (1994a). Classification of radioactive waste. A safety guide. Safety series No 111-G-1.1.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 178 26. IAEA (1994b). Siting of near surface disposal facilities. Safety Series No. 111-G- 3.1

27. IAEA (1996). Requirements and Methods for Low and Intermediate Level Waste Package Acceptability. IAEA-TECHDOC-864. IAEA, Vienna.

28. IAEA (1999). Near surface disposal of radioactive waste. Requirements. Safety Standards Series No WS-R-1

29. ICRP (1998) Annals of the ICRP, Publication 81 Radiation protection recommendations as applied to the disposal of long-lived solid radioactive waste.

30. IGS (1999). D Bugai (ed.) Interim report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Task 1 ‘Review of the available data’. Kiev.

31. ISTC Shelter (1996). Analysis of safety for Object ‘Shelter’ and forecast of future developments. Report PO Chernobyl NPP (in Russian).

32. ISTC Shelter (1998a). Inventory taking, summarization, and analysis of data on types and volumes of radioactive material, concentrated at the Industrial Zone of the Shelter. Task 1. Project No. B7-5200/97/000077/MAR/C3. ISTC "Shelter".

33. ISTC Shelter (1998b) Results evaluation of the Shelter Industrial Zone radioactive wastes inventory taking and development of technology for their removal. Task 6. Project No. B7-5200/97/000077/MAR/C3. ISTC "Shelter", 1998.

34. ISTC Shelter (1998c) Carrying out the measurements at the Shelter Industrial Zone. Task 5. Project No. B7-5200/97/000077/MAR/C3. ISTC "Shelter", 1998.

35. ISTC Shelter (2000). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Information on tasks 2, 3, 4 and 5.

36. Ivanov Yu.A., Kashparov V.A, Levchuk S.E, Zvarich S.I. (1996) 1. Vertical migration of radionuclides in soils in area contaminated by accident at ChNPP. I. Long-term transport in situ processes in soils. // Radiohimiya –1996, v.38, issue 3, pp.264-272 (in Russian).

37. Kashparov V (1999) Ukrainian Institute of Agricultural Radiology. 1999 experimental data.

38. Kashparov V, Homutinin Yu, Zvarich S., Bugai D. A. (ed) (2000). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Estimates of inventory and characteristics of soil contaminated with transuranic radionuclides. Kiev.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 179 39. Kholosha VI Proskura NI et al (1999). Radiological and ecological significance of natural and artificial objects of the exclusion zone. Bulletin of the ecological state of the Exclusion Zone No 13, 1999, pp3-8

40. Konrad (1995). Anforderungen an endzulagernde radioaktive Abfälle (Endlagerungsbedingungen, Stand: Dezember 1995) - Schachtanlage Konrad. (ET-IB-79). Bundesamt für Strahlenschutz, Salzgitter, December 1995. (Provisional Waste Acceptance Criteria Konrad).

41. Kulachinsky A V et al (1996) Study of radioactive contamination of Pripyat Inlet. In: Abstracts of Five International Scientific and Technical Conference, Chernobyl – 96, Zeleny Mys, 1996, pp70-71.

42. Ledenev A I, Ovcharov P A, Levchuk S E, Budai D A (ed) (2000). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Summary of information on PZRO 3-d Phase of ChNPP (Kompleksny). Kiev.

43. Levchuk S. E. (2000). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Verification of the formulae currently used by SSE Complex to estimate activity of radwaste of Chernobyl origin based on the exposure dose-rates.

44. Mandrik D.E. (1998) Methodology for measuring radioactivity when identifying characteristics of radwaste at PZRO Buryakovka. Laboratory of Metrology, GSP RUOOD. Kiev.

45. Marchenko V I, Doroshenko V I (1997) Radiological State of the Exclusion Zone. Bulletin of ecological state of the Exclusion Zone. Volume 10, 1997, pp4-13

46. NEA (1986) Shallow Land Disposal of Radioactive Waste. Reference levels for the acceptance of long-lived radionuclides. Nuclear Energy Agency

47. NIPIPromtechnologii (1992). Research report: ‘Study of radwaste disposal sites, development of technologies and measures to localise and redispose the wastes, implementation of radiological and hydrogeological monitoring in the area of GLVSRVDODQGDGMDFHQWWHUULWRULHV&KHUQRE\O133$UFKLYH   Moscow- Chernobyl (in Russian).

48. Novikov A A (2000). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Treatment and disposal of radwastes Vector complex. Slavutich.

49. OPBS (1983). Principle regulation on safety and physical protection during nuclear materials transportation. In Russian.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 180 50. OP ChNPP (1998). Definition of quantities and qualities, and characteristics of solid radwastes from OP ChNPP. Preliminary report from 28.05.1998

51. OP ChNPP (1999). The concept of radwaste management at the object ‘Shelter’. $FFHSWHG2FWREHU3URWRFRO1R  DUFKLYHVRI2EMHFW ‘Shelter’ (in Russian).

52. OSAT (1999a). Final report on the inventerisation of radwaste in the Chernobyl Exclusion Zone. OSAT. Doc.Ref. OSAT/RPT/OSA/00031, June 1999.

53. OSAT (1999b). Review of waste containers approved for and/or in use at the ChNPP and exclusion zone, OSAT/RPT/OSA/00030, Issue N°2, 01/07/99

54. OSP (1987) Basic Safety Rules for handling radioactive substances and other sources of ionising radiation (OSP-72/87)

55. Ovcharov P A, Ledenev A I, Budai D (ed)l (2000). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Review of information on the inventory and characteristics of the radwaste, which is concentrated within the studied PVLRO sectors in the Near Zone of ChNPP. Kiev.

56. PBTRB (1973) Regulation on radioactive materials transportation. In Russian.

57. Skalsky A S, Bugai D A (ed) (2000). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Information on the assessment of risks and prioritisation of the radwaste dumps in the Chernobyl Exclusion Zone. Part II Kiev.

58. SPAS (1988) Safety rules for the design and operation of Nuclear Power Plants

59. SPORO (1985). Safety rules for radwaste management. SanPiN. 42-129-11– 3938–85 (in Russian).

60. SSE Complex (1990a). Safety licence for PZRO ‘Podlesny’. Authorised by V L Kultenko and A T Usayev. Pripyat (in Russian).

61. SSE Complex (1990b) Results of inventarisation of disposal and storage sites as of 01.01.1990.

62. SSE Complex (1990c) Safety licence for PZRO ‘Chistogalovka’. Authorised by V L Kultenko and A T Usayev. Pripyat (in Russian).

63. SSE Complex (2000). Company standard. Radwaste management. Current status of radwaste disposal site ‘Podlesny’. STP 108.001-2000.

64. STC KORO (1993). Development of conservation projects for PVLRO within the 30-km Exclusion Zone. Phase 1.3. Completion of characterisation of PVLRO

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 181 sector Yanov, collation of field and laboratory measurements, compilation of the data. Chernobyl (in Russian).

65. STC KORO (1994). Development of conservation projects for PVLRO within the 30-km Exclusion Zone. Phase 1.2. Completion of characterisation of PVLRO, sampling and analysis of soil and water, compilation of field measurements, installation of ‘Radiological Danger’ signs. Zheltiye Vody – Chernobyl (in Russian).

66. STC KORO (1995a). Development of conservation projects for PVLRO within the 30-km Exclusion Zone. Phase 1.2. Completion of characterisation of PVLRO, sampling and analysis of soil and water, compilation of field PHDVXUHPHQWVLQVWDOODWLRQRIµ5DGLRORJLFDO'DQJHU¶VLJQV&RQWUDFW   Zheltiye Vody – Chernobyl (in Russian).

67. STC KORO (1995b). Technical and economic justification (TEO) for the construction of radwaste management and disposal centre based on Komplex Vector. Zheltiye Vody (in Russian).

68. 67&.252 D 5HSRUWRQWKHUHVHDUFKFRQWUDFW  µ,QYHVWLJDWLRQRI the Stroybaza sector and inventarisation of PVLRO, located in the path of FRQVWUXFWHGURDG$UFKLYH  &KHUQRE\O

69. STC KORO (1996b). Development of projects of PVLRO ‘conservation’ within the 30-km Exclusion Zone. Phase 17. Estimation of reliability of radwaste disposal in PVLRO Kompelksny and environmental impact from it. Contract  =KHOWL\H9RG\ LQ5XVVLDQ 

70. STC KORO (1998). Report “Investigation of PVLRO ‘Peschannoye Plato’, preparation of data for input into GIS of radwaste and the dump database, analysis of PVLRO’s safety and decision-making. Radiological survey of PVLRO ‘Peschannoye Plato’ and analysis of dumps on the environment”. Chernobyl- Zheltiye Vody (in Russian).

71. 67&.252  5HSRUWRQFRQWUDFW  ³,QYHVWLJDWLRQRI PVLRO ‘Peschannoye Plato’, preparation of data for input into GIS of radwaste and the dump database, analysis of PVLRO’s safety and decision-making.. Phase 11. Preparation of the final report on sector 3.5 of PVLRO ‘st. Yanov’ and analysis of Environmental Impact of radwaste. Zheltiye Vody, Chernobyl (in Russian).

72. TACIS (1995) Management of Radioactive Waste in Dumps in the Chernobyl Exclusion Area. TACIS UR/029.

73. UDK NPO Pripyat. Temporary guidance on the measurement and estimation of the total activity of SRW which is accepted at PZRO Buryakovka.

74. Ukrainian Hygenic Regulations (2000) GN 6.6.6.054.2000 Radiological regulations for the protection of the population from the disposal of radwaste and waste acceptance criteria for surface disposal. 6 March 2000.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 182 75. 91,3,(7 D µ'HVLJQIRUVHDOLQJ3=52µ3RGOHVQ\¶  LQ Russian)

76. VNIPIET (1991b). “Post-closure safety justification for PZRO Podlesny. Interim 5HSRUW  LQ5XVVLDQ

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page 183 $SSHQGLFHV

$SSHQGL[$0HWKRGVRIGDWDDFTXLVLWLRQDQGDQDO\VLV $2YHUYLHZRIPHWKRGRORJ\ A similar methodology was used to determine the waste inventory of each of the waste dumps. During surveys of the contaminated soils within the Industrial Zone and the waste in the PZROs and PVLROs, exposure dose rates at the surface and within the waste bodies were measured. From these measurements of exposure dose rate and the known dimensions of the waste dumps, regions containing radioactive waste were identified and their volumes estimated. In order to estimate the activity of the waste, the values of exposure dose rate were converted to values of Cs-137 specific activity. The relationship between exposure dose rate and Cs-137 specific activity was determined as follows:

- For contaminated soils within the Industrial Zone, by modelling the exposure from a borehole; - For the PZROs, by using a theoretical formula derived for a gamma radiation source of semi-infinite geometry; - For PVLROs, by using an empirical formula.

For contaminated soils within the Exclusion Zone (outside the Industrial Zone) Sr-90 mapping was performed.

Contamination of the near accident zone surrounding the ChNPP (radius 3-5km), where the PVLROs are concentrated and where the radioactive wastes contained in the PZROs mainly originated, is associated with the fallout of finely dispersed nuclear fuel particles. The initial fuel particle radionuclide composition was close to that of the irradiated fuel of the ChNPP Unit 4 at the time of the accident. Correlation ratios between the activities of radionuclides in the Unit 4 fuel at the time of the accident, adjusted for radioactive decay and daughter product ingrowth, provides a method of characterising the radionuclide composition of Chernobyl wastes:

Ai = cij * Aj

th where; Ai is the activity of the i radionuclide th th cij is the correlation ratio between the activity of the i and j radionuclides.

Correlation ratios were used to determine the activities of the other main dose-contributing radionuclides from the activities of Cs-137 and Sr-90, as follows:

- For the Industrial Zone, correlation ratios corresponding to the average values for fuel from Unit 4 ChNPP were used; - For Kompleksny, correlation ratios derived for fuel containing waste for the year 2000 were used; - For Buryakovka and the PVLROs, empirical correlation ratios were used obtained from sampling data; - For contaminated soils, correlation ratios were determined experimentally for the Near Zone.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page A-1 For details of the specific methodologies of data acquisition and analysis used at individual sites/waste dumps see below.

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Measurements of exposure dose rate and the angular distribution of gamma-radiation within the Industrial Zone were analysed using a retrospective method to determine the location of radioactive waste within the Industrial Zone [ISTC, 2000]. As a result those locations containing high concentrations of radioactive waste were identified within the Unit “Shelter” Local Zone.

The Unit “Shelter” Local Zone was divided into sections on the basis of:

- similarity of waste conditions; - estimated waste quantity; - location of waste with respect to Unit Shelter.

Investigations within the Unit “Shelter” Local Zone included core sampling and gamma logging of boreholes. The quantity of radioactive waste within each section was estimated [ISTC, 1998a]. Investigations of the borehole equivalent dose rate data and the 137Cs specific activity in core samples [ISTC, 2000] allowed the depth profile of radioactive contamination to be characterised in detail.

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The waste physical characteristics were determined from studies of core samples [ISTC 1998a and 1998c]. The investigations of the core samples allowed the man-made and undisturbed sub-soil layers to be characterised in detail.

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The values of exposure dose rate from borehole logging were converted to values of 137Cs specific activity. The coefficient used for the conversion was obtained by modelling γ- exposure from a borehole for a specific correlation ratio. The resulting activity to exposure rate coefficient was estimated to be k=19.35 MBq K NJÂP6Y 7KHNYDOXHWDNHVLQWRDFFRXQW the change in radioisotope activity from the time of the measurement of equivalent dose rate in 1997 until the 26th of April 2000.

The 137Cs specific activity in the soil layer was estimated by the following formula: A=k + where A = 137Cs specific activity, MBq/kg (April 26, 2000); H = equivalent dose rate measured in borehole at a given layer, mSv/hour (1997); k=19.35 MBq K NJÂP6Y 

The 137Cs specific activity was estimated with depth for each section of the “Shelter” Local Zone, from the gamma-logging results.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page A-2 Correlation ratios for the waste in the Shelter Local Zone were determined from the radiometric and radiochemical analysis of core samples from the “Shelter” Local Zone [ISTC, 1998a & 1998c]. The ratios obtained for some samples deviated significantly from the average values. However, the estimated average values of the ratios corresponded to the average values for fuel from Unit 4 of the Chernobyl NPP. Thus average fuel correlation ratios [ISTC, 1996], as recalculated for the 26th of April 2000, were used to estimate the specific activity of radionuclides in the “Shelter” Local Zone from the 137 Cs specific activity.

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The classification of the radioactive waste [ISTC, 1998a & 1998c] was determined based on :

- the results of the analysis of core samples; - interpretation of the results from gamma logging of boreholes.

For classification of wastes in line with the Ukrainian standards (see Section 2.1) within the Local Zone, the following method was used:

1. The exposure dose rates, which are produced by a package of cylindrical form of a specific radioactive waste category within a distance of 0.1m, were estimated using mathematical modelling; 2. The exposure dose rate values in boreholes, which represent wastes of corresponding categories, were calculated; 3. On comparison of the results for each waste category with the relevant Ukrainian standard, the following values for 137Cs activity for each waste group were obtained for gamma-logging geometry (fuel composition for April 26, 2000): 4. 0.05 – 15.5 MBq/kg for low-level waste; 15.5 – 650 MBq/kg for intermediate-level waste; 650 MBq/kg for high-level waste;

5. According to the IAEA classification system, the limit for short-lived wastes is 400 Bq/g of long-lived alpha emitting radionuclides. This was estimated, for the Industrial Zone wastes, to correspond to a 137Cs activity of 160 MBq/kg.

“CYCLON” computational programs complex was used for the mathematical modelling. “CYCLON” was tested by comparing the results obtained using this code with those obtained when using different codes such as “MCBEND”, “RANKERN”, “QAD-CGGP”, “ALBEB”, which are used in the nuclear industry in Great Britain. The tests showed that the “CYCLON” results corresponded well with those produced using the other codes.

The activity distribution with depth was estimated using values of borehole exposure dose rate. This allowed layers containing radioactive waste of different categories (i.e. HLW, ILW, LL and SL LLW waste) to be distinguished for each section using IAEA and Ukrainian systems of waste categorisation [ISTC, 1998b].

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page A-3 $0HWKRGVRIGHWHUPLQLQJZDVWHLQYHQWRU\IRU3=52.RPSOHNVQ\ The dose rate measurements obtained during the 1996 survey of PZRO Kompleksny largely correspond to the uppermost layer of waste in the compartments, and hence in order to assess the waste activity a gamma-radiation source of semi-infinite geometry was assumed. It was also assumed that the gamma dose rate is dominated by caesium-137. Based on these assumptions the specific activity of caesium-137 is given by the following formula [Levchuk, 2000]:

Am = D µen / (2 π Γ) (1) where; m – the Cs-137 specific activity of the source (Ci/kg); D – gamma dose rate of the radioactive source (R/hour); 2 µen – energy absorption mass factor (cm /g); 2 FDHVLXPJDPPDFRQVWDQW 5 FP /(hour*mCi))

Using the formula (1) the average specific activity of caesium-137 was determined from the average value of exposure dose rate measured. Since the radioactive waste in the PZRO originated from the ChNPP site, correlation ratios for the ChNPP site waste, determined by experts from ISTC “Shelter”, were used to assess the activity of the other main dose- contributing radionuclides and transuranic elements (see Table A1).

In order to determine the maximum specific activity of caesium-137 in PZRO Kompleksny, data on maximum dose rates detected on the walls of containers inside the storage facility were used. In order to determine the maximum specific activity of caesium-137 from the dose rate measurements a formula similar to (1) but for an infinite geometry was used. (The factor of 2π in the formula for a semi-infinite geometry, which had been used by STC KORO in previous assessments, was replaced by 4π for an infinite geometry representation, which led to a factor of 2 decrease in the estimate of overall inventory).

Table A1. Correlation between the activities of radionuclides in the fuel-containing waste in the ChNPP site for year 2000, according to ISTC “Shelter” data [ISTC, 1996].

Radionuclide Ratio to the activity of caesium-137, % 137Cs 100 90Sr 84 238Pu 0.6 239Pu 0.5 240Pu 0.8 241Pu 48 241Am 1.6

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Prior to 1997 the volume of radwaste disposed at Buryakovka was determined by filling a truck, and the radwaste mass was calculated using the estimated waste density. In 1997 truck scales (504 2PC-30 DC24AcM1) were installed at Buryakovka, allowing the mass of

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page A-4 radioactive waste to be measured directly. The scales can measure mass in the range 0.2-5.0 tonnes (error ± 10 kg), 5.0-20.0 tonnes (error ± 15 kg), and 20.0-30.0 tonnes (error ± 20 kg).

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The total and specific activity of each batch of radioactive waste arriving at Buryakovka is determined according to the technique developed by the State Specialised Enterprise “Radek” [UDK NPO Pripyat]. The exposure dose rate for each waste batch is measured using DP-5V and MKC-01R dosimeters. The total activity of the waste is related to the exposure dose rate according to the following formula:

     (1) where; A is total activity of the waste, mCi LVWKHPDVVRIWKHUDGLRDFWLYHZDVWHLQWKHWUXFNWRQQHV LVDYHUDJHH[SRVXUHGRVHUDWHP5K

Details relating to the derivation of this formula (1) are specified in Appendix C.

It should be noted that the formula (1) was derived using the following assumptions: the waste gamma-activity is mostly determined by Caesium-137; the Caesium-137 contribution to the total gamma- and beta- activity is approximately 50%; and, the contribution of alpha- emitting transuranic (TRU) elements to the total activity is approximately 1.5% (Table A2).

DEOH$5DGLRQXFOLGHFRPSRVLWLRQRI&KHUQRE\OZDVWHVXVHGWRGHWHUPLQHWKHDFWLYLW\RI wastes disposed at Buryakovka from measurements of exposure dose rate [UDK NPO Pripyat] (See Appendix C).

Radionuclide Contribution to waste total activity, % 90Sr 20.7 134Cs 1.1 137Cs 46.6 238Pu 0.23 239,240Pu 0.64 241Pu 30.0 241 Am 0.65

The above methodology used by SSE Complex to estimate radioactivity from gamma-dose rate measurements [Mandrik, 1998] was found to be accurate.

5DGLRQXFOLGHFRPSRVLWLRQ

Sampling of radioactive waste in trucks is performed twice per month (with 5 samples being taken from each truck). The waste in the trucks is predominantly loose of homogeneous composition and the sampling points are selected at uniform intervals throughout the truck load. The samples are measured for gamma-emitting radionuclides, with the error in the Cs- 137 detection not exceeding 15%. Some of samples are also subject to radiochemical analysis in order to determine the 90 Sr and plutonium isotope content of the waste.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page A-5 Analysis of the sampling data for Trench #25 has been performed by IGS, based on data provided by SSE “Complex”, as follows:

1. The correlation ratios between Caesium-137 activity and the activity of other radionuclides were estimated using the results from the analysis of samples. The obtained correlation ratios were compared with those used for the estimation of the activity disposed at Buryakovka from exposure dose rate measurements according to the instruction developed by SSE “Radek” [UDK NPO Pripyat]. 2. A comparison was made between the values for Caesium-137 specific activity obtained from direct measurements of samples and obtained indirectly from an assessment of the measurements of exposure dose rate. 3. The correlation ratios for radionuclide specific activities (specific to trench #25) determined from the analysis of waste samples were used to re-assess the contribution of individual radionuclides to the total activity contained in trench #25. 4. Using the statistical distribution of the exposure dose rates measured for the waste batches, the statistical distributions of the specific activities of Caesium-137 and of transuranic elements were determined for Trench #25.

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Previous assessments of the waste inventory of the surveyed PVLROs [Ovcharov et al, 2000] focussed on the concentrations of caesium-137, strontium-90, and the sum of plutonium-239 and plutonium-240. Within the current project the waste inventory of the PVLROs has been re-assessed taking into account the contribution of plutonium-241, plutonium-238, and americium-241 in addition to the above radionuclides. Inclusion of these additional radionuclides has resulted in significant changes to the estimated beta-activity and, in particular, the total alpha-activity.

The revised calculations of the waste inventory of the PVLROs were performed by the Scientific and Technical Centre “KORO”, based on consultations with the Institute of Geology Sciences and the recommendations of B.A. Kashparov [IGS, 1999].

The methods used during the survey of the PVLROs performed by NIPIPromtechnologii and the Scientific and Technical Centre “KORO” are described in detail in the report on the Contract Stage1 [IGS, 1999]. Gamma dose rates were measured inside boreholes drilled into the waste dumps. The caesium-137 specific activity of the waste was calculated from the measurements of gamma dose rate using an empirical formula. Correlation coefficients were then used to calculate the specific activities of the other radionuclides present in fuel- containing waste.

These methods were first implemented by the Institute NIPIPromtechnologii while surveying Sector 2.1 of PVLRO Ryzhy Les in 1992 [NIPIPromtechnologii, 1992]. To estimate the 137Cs activity from the average value of the dose rate, the following formula was used

137 A Cs = 9.3E-7 * 0.85 * X (1)

Where;A 137Cs is the 137Cs specific activity in the waste, (Ci/kg) LVWKHDYHUDJHYDOXHRIGRVHUDWHLQVLGHWKHGLVSRVDODUHD P5KRXU

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page A-6 0.85 is the 137Cs contribution to the total activity of gamma-emitting radionuclides in 1992.

For the PVLRO Ryzhy Les, NIPIPromtechnologii determined the following correlation ratios (for 1992) based on experimental data:

90 137  Sr = 0.7 * A Cs, (2) A 239.240Pu = 0.9E-2 * A137Cs.

The equations (1) – (2) were also used by the Scientific and Technical Centre “KORO” from 1993 - 1995 to estimate the waste characteristics for Sectors 3.1 and 3.2 of Stantziya Yanov and for Sector 5.1 of Neftebaza.

In 1995, the Scientific and Technical Centre “KORO,” using data from the analysis of a large number of waste samples from the PVLRO Sectors, derived the following formula for the relationship between caesium-137 specific activity in the waste and the measured dose rate [STC KORO, 1995a]:

A137Cs= 46.1 * X (3) Where; A = specific activity of Cs-137 in waste, Bq/g X = dose rate, mR/hour

New empirical correlation ratios were also determined by STC KORO from the sampling data in order to derive the activity of the main dose-contributing radionuclides from the caesium-137 activity (see Table A3).

Equation (3) and the sample correlation ratios specified in Table A2 (Column 2) were used by STC “KORO” from 1995-1999 in order to characterise the waste within Sectors 5.2 and 5.3 of Neftebaza, Sector 6.0 of Peschannoe Plato, and Sector 3.5 of Stantziya Yanov. These assessments of the waste inventory concentrated on the activities of caesium-137, strontium- 90 and plutonium-239, 240.

Table A3. Correlation coefficients for deriving activities of main dose-contributing radionuclides from Cs-137 activity in Chernobyl fuel-type waste (for 1995)

Radionuclide STC “KORO” Institute for data obtained Agricultural Radiology from PVLRO data for ChNPP Unit 4 waste samples fuel 1 2 3 137Cs 1.0 1.0 90Sr 0.73 0.86 134Cs 2.49E-2 3.7E-2 154Eu 1.15E-2 3.1E-2 155Eu 0.87E-2 1.5E-2 238Pu 0.5E-2 0.55E-2 239,240Pu 1.22E-2 1.2E-2 241Pu - 0.54 241Am - 1.05E-2

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page A-7 Within the framework of the current project, STC “KORO” has re-assessed the waste inventory for the surveyed PVLRO Sectors, taking into account a more complete list of radionuclides including americium-241 and plutonium-241. No experimental data relating to the correlation coefficients for plutonium-241 and americium-241 are available and hence the data relating to these radionuclides obtained by the Institute for Agricultural Radiology for ChNPP Unit 4 fuel were used (Table 1, Column 3). As Table 1 shows, the experimental correlation ratios obtained by the Scientific and Technical Centre “KORO” for the other plutonium isotopes are close to the values for Chernobyl Unit 4 fuel calculated from the data provided by the Institute for Agricultural Radiology (UkrNIISKhR).

0HWKRGVXVHGWRHVWLPDWHYROXPHVRIZDVWHLQVXUIDFHDQGQHDUVXUIDFHVRLOOD\HUVIRU 39/521HIWHED]D

The waste volume in the surface layer (0-0.05m depth) has been calculated for Sectors 5.2 and 5.3 of Neftebaza, based on data obtained during the surveys of the PVLROs performed between 1992 and 1999.

The methodology used to calculate the volume of waste in the surface layer is as follows [STC KORO, 1995a]:

- Gamma-dose rate measurements were made in the Sector on a 10x10 m grid. A single value of dose rate was assigned to each grid cell. - Based on the measurements of the gamma-dose rate corresponding to each grid cell, Sector 5.2 was subdivided into five zones and Sector 5.3 was subdivided into seven zones. - The volumes of waste concentrated in each zone were calculated, using the known areas of the grid cells and the layer depth of 5cm.

Waste volumes in the near-surface layer (0.05-0.5m depth) were determined in detail only for Sector 5.3 of Neftebaza, due to the large number of contamination sources in this layer.

The methods used for the estimation of the waste volume in the near-surface layer are as follows:

- Gamma-dose rate measurements were made on a 5x5m horizontal grid, with dose rates being measured at depth intervals of 0.2m to a depth of 1m. Where contamination was detected at a depth of 1m, the grid size was reduced to 2.5m and occasionally to 1m; - For each measurement depth (0.2, 0.4, 0.6, 0.8 and 1.0 m) a horizontal cross-sectional plan showing the variation in dose-rate was produced; - These cross-sectional plans were used to calculate the waste volumes using the following formula:

Vi = (Si-1 + Si) / 2 * h

3 Where Vi is the volume of contaminated soil at the depth i, m

Si-1, Si surface area of contaminated soil at the (i-1)th and ith layers respectively, m2 h is the thickness of the layer, equal to 0.2m.

- The volume and mass of waste within each layer were summed.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page A-8 $0HWKRGVXVHGIRUPDSSLQJWKHFRQWDPLQDWLRQRIVRLOVDFURVVWKH([FOXVLRQ=RQH 'DWDDFTXLVLWLRQ

The contamination of soils within the Exclusion Zone by transuranic elements (TRU) was investigated by performing Sr-90 mapping. A sampling grid of about 13,000 points, spaced at 1-2km intervals, was established within the 30-km Exclusion Zone. In regions of high gradients in soil contamination a finer sampling grid, with sampling points at 100-500 m intervals, was used. For each 5m2 sampling area, five boreholes were drilled to a depth of 30cm, with a distance between each hole of 2-5m, and measurements of Sr-90 contamination were taken using a cylindrical-sampling instrument with a diameter of 37mm. Also the dose rates were measured at each point. Due to the large overall sampling area (about 2,000 km2) and the current inaccessibility of some areas, the sampling teams were moved with the aid of helicopters. Motor vehicles were used in areas inaccessible to helicopters i.e. forests and the ChNPP 5-km zone.

Data on 90Sr migration in the soil [Ivanov et al, 1996] revealed that 10 years after the accident about 95% of the Sr-90 activity was concentrated in the top 10-20cm of soil. High rates of vertical migration of 90Sr are observed only in the sandy soils without humus or vegetation, where the 90Sr accumulation in the top 30cm of soil may be 30-50%. Thus, sampling was conducted at all points to a depth of 30 cm and in sandy soils sampling was increased to a depth of 1m.

Measurements of the vertical distribution of 90Sr in the soil were taken using layer-sampling methods. A specially developed methodology was applied to assess the vertical distribution of 90Sr in the soil. This involved high efficiency detection of beta particles emitted by 90Y (the daughter product of 90Sr) compared to gamma-photon detection. This was achieved by using a plastic scintillation detector in the form of a ring (∅ - 50 mm, height - 20 mm, width - 8 mm). The range of energies of beta particles detected was 0.02-3.5 MeV, with a count rate of up to 106 s-1. A metal screen made it possible to take into account the contribution of associated gamma-photons measured by the detector. The duration of measurement was 100 seconds, resulting in the minimum specific activity of 90Sr that could be detected in the soil being 160 Bq/kg.

A 90Sr contamination density map of the near-field zone was developed, based on the GPS (global positioning system) co-ordinate system.

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The contamination of a particular area by a given radionuclide can be described as a continuous function of the area co-ordinates, I [ \  During sampling, the value of this function is measured at a finite number of points [L\L where L ranges from 1-n, which are randomly located within the investigation area. The values of the function I [L\L measured, are characterized by a random error, which is introduced both by the sampling and measurement processes. Thus, the measurements performed at a point [\ fail to determine the value of the function I [\ . What is actually measured is the value of a function ϕ [\ as defined by the following equation:

ϕ([, \) = I ([, \) +ξ([, \) (1)

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page A-9 where ξ [\ = random error

It is thus necessary to extrapolate the measurements taken across the studied area, taking into account the random error ξ [\ . Such problems are generally identified as trend-analysis problems and are widely encountered when developing geological and geophysical maps. As a rule these problems are solved using the so-called Kolmogorov-Viner’s optimum detecting filter [Aronov, 1990], which is based on the following equation:

ˆ 2 0 []I ([, \) − I ([, \) = min (2) ˆ where I ([, \) = assessment of the function I [\ , obtained by the values of the function ϕ [L\L 

The “Kriging” method [David, 1980] is one of a variety of Kolmogorov-Viner’s optimum detecting filters which has received wide application and acceptance. The “Kriging” method is applied when handling and treating geophysical, geochemical data, making geometrization of orebodies and other pools, and when developing geological and geophysical maps. The = { } “Kriging” method determines the function J([L , \ M ) /Q I ([L , \ M ) and as a precautionary measure against negative values resulting from interpolation in the region of small values of I [L\M . The values of the required function of contamination are then calculated using the = following formula: I ([L , \ M ) exp{J([L , \ M )}.

The “Kriging” method formed part of the ‘Surfer’ software package which was applied to the field measurements of 90Sr contamination across the Exclusion Zone. This corrected the results for the random error introduced during the sampling and measurement processes.

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The correlation ratios between the activity of 90Sr and TRU for the Near Zone were determined experimentally. From Figure A1 it can be seen that the experimental data conforms to a straight-line relationship between the activity of Sr90 and of 239+240Pu, confirming that the use of a single correlation ratio is applicable. The experimental value determined for the ratio between the activities of Sr90 and 239+240Pu is 52.3 (Figure A3). The correlation ratios between 239+240Pu and the TRU elements were determined as follows: 239+240Pu/238Pu = 1.8; 241Pu/239+240Pu = 36; 241Am/239+240Pu = 1.3; and 239+240Pu /244Cm = 9.9.

Using the correlation ratios between the 90Sr and the TRU activities, corresponding to the year 2000, the TRU content of the contaminated surface layer of soil within the Exclusion Zone was determined.

The calculated overall TRU alpha activity 238Pu, 239Pu, 240Pu, 241Am, 244Cm and their specific activities (Bq/g) in a 10cm thick near-surface layer of soil were summed and a map of the total TRU concentration was developed. The concentration of a 10cm thick layer of soil was taken to be 1.5 t/m3.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page A-10 250.0 R2 = 0.94 200.0

150.0

100.0 3XN%TP 50.0

0.0 0.0 2000.0 4000.0 6000.0 8000.0 10000.0

6UN%NP

Figure A1. – Ratio between 90Sr and 239,240 Pu contamination density in the near-field region.

250.0 R2 = 0.99 200.0

150.0

100.0

3XN%TP 50.0

0.0 0.0 50.0 100.0 150.0 200.0

(XN%TP

Figure A2 – The relationship between 154Eu and 239,240 Pu contamination density in the near- field region soil.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page A-11 30 % 25 20 Average-52.3 σ 15 - 15.3 10 Frequency 5 0 20 30 40 50 60 70 80 90 100 Sr/Pu

Figure A3. – The distribution of the ratio 90Sr/239+240Pu in the near-field zone.

$5HIHUHQFHV Aronov V.I. (1990). Computational mapping methods for geological and geophysical indicators and sealing of oil and gas resources. Moscow, Nedra (in Russian).

David M. (1980) – Geostatical methods for estimating ore reserves. Moscow, Nedra (in Russian).

IGS (1999). D Bugai (ed.) Interim report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Task 1 ‘Review of the available data’. Kiev.

ISTC Shelter (1996). Analysis of safety for Object ‘Shelter’ and forecast of future developments. Report PO Chernobyl NPP (in Russian).

ISTC Shelter (1998a). Inventory taking, summarization, and analysis of data on types and volumes of radioactive material, concentrated at the Industrial Zone of the Shelter. Task 1. Project No. B7-5200/97/000077/MAR/C3. ISTC "Shelter".

ISTC Shelter (1998b) Results evaluation of the Shelter Industrial Zone radioactive wastes inventory taking and development of technology for their removal. Task 6. Project No. B7- 5200/97/000077/MAR/C3. ISTC "Shelter", 1998.

ISTC Shelter (1998c) Carrying out the measurements at the Shelter Industrial Zone. Task 5. Project No. B7-5200/97/000077/MAR/C3. ISTC "Shelter", 1998.

ISTC Shelter (2000). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Information on tasks 2, 3, 4 and 5.

Ivanov Yu.A., Kashparov V.A, Levchuk S.E, Zvarich S.I. (1996) 1. Vertical migration of radionuclides in soils in area contaminated by accident at ChNPP. I. Long-term transport in situ processes in soils. // Radiohimiya –1996, v.38, issue 3, pp.264-272 (in Russian).

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page A-12 Levchuk S. E. (2000). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Verification of the formulae currently used by SSE Complex to estimate activity of radwaste of Chernobyl origin based on the exposure dose-rates.

Mandrik D.E. (1998) Methodology for measuring radioactivity when identifying characteristics of radwaste at PZRO Buryakovka. Laboratory of Metrology, GSP RUOOD. Kiev.

NIPIPromtechnologii (1992). Research report: ‘Study of radwaste disposal sites, development of technologies and measures to localise and redispose the wastes, implementation of radiological and hydrogeological monitoring in the area of disposal and DGMDFHQWWHUULWRULHV&KHUQRE\O133$UFKLYH  0RVFRZ&KHUQRE\O LQ Russian).

Ovcharov P A, Ledenev A I, Budai D (ed)l (2000). Report on NNC contract C6063/F4695 ‘Review and Analysis of Solid Long-lived and High Level Radioactive Waste arising at the Chernobyl Nuclear Power Plant and the Restricted Zone’. Review of information on the inventory and characteristics of the radwaste, which is concentrated within the studied PVLRO sectors in the Near Zone of ChNPP. Kiev.

STC KORO (1995a). Development of conservation projects for PVLRO within the 30-km Exclusion Zone. Phase 1.2. Completion of characterisation of PVLRO, sampling and analysis of soil and water, compilation of field measurements, installation of ‘Radiological 'DQJHU¶VLJQV&RQWUDFW  =KHOWL\H9RG\±&KHUQRE\O LQ5XVVLDQ 

UDK NPO Pripyat. Temporary guidance on the measurement and estimation of the total activity of SRW which is accepted at PZRO Buryakovka.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page A-13 $SSHQGL[%/D\RXWRIZDVWHGXPSVLQ&K133&LYLO'HIHQFH7URRS=RQH   %DVHGRQ6FLHQWLILF7HFKQLFDO&HQWUH³.252´GDWD 

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page B-1 $SSHQGL[&'HULYDWLRQRIWKHIRUPXODXVHGIRUWKHFDOFXODWLRQRIWKHWRWDO DFWLYLW\ RI WKH UDGLRDFWLYH ZDVWH DFFRUGLQJ WR WKH H[SRVXUH GRVH UDWH IRU %XU\DNRYND (Temporary instruction for the performance of measurements and the estimation of the total activity for solid radioactive waste accepted at Buryakovka, Dosimetric Control Administration Scientific Industrial Union “Pripyat”).

The exposure dose rate on the surface of volumetric semi-infinite uniform (homogeneous) mono-energetic gamma-emission source, taking into account the dispersed component, can be estimated by the following formula

π µ expÃ= (2 G / s  $s, where ( 1 )

exp – exposure dose rate, R/hour; 2 *UDGLRQXFOLGHJDPPDFRQVWDQW 5 FP  KRXU P&L  3 s - source specific volumetric activity, mCi/cm ; µ -1 s OLQHDUFRHIILFLHQWIRUSKRWRQHQHUJ\DEVRUSWLRQLQWKHVRXUFHPDWHULDO P .

The source material density (i.e. the solid radioactive waste density) may deviate from the tabulated values for material density (concrete, water, metal, sand, etc.) resulting in the linear absorption coefficient µs deviating from the tabulated value.

In this case it is more convenient to re-state Formula (1) using mass parameters:

π µ exp = (2 G / m   m ( 2 )

ZKHUH m – source specific mass activity, mCi/g; µm - mass coefficient for photon energy absorption in the source material, cm2/g.

The mass coefficient for absorption (µm) is connected to the µs linear coefficient as follows

µ Ã= µs/ρ, ( 3 )

where ρ – material density tabulated value, g/cm3.

µ ÃÃvalues for the different energies of photons are tabulated.

Currently 90 % of exposure dose rate in the ChNPP zone is due to 137Cs and in future the 137 Cs contribution to exposure dose rate will increase. Therefore, µ Ãvalues which correspond to 137Cs emission for solid radioactive waste of Chernobyl origin have been used.

2 For the basic solid radioactive waste types the µ ÃFRHIILFLHQWKDVWKHIROORZLQJYDOXHV P /g:

“Water” “Concrete” “Metal” (paper, wood) (ground, construction waste) (scrap metal) 0.0326 0.0293 0.0280

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page C-1 µ π $FFRUGLQJWR)RUPXOD   m = ( m / 2 *   exp ( 4 )

137 2 For &VJDPPDFRQVWDQW* [ 5[ P ) / (hour x mCi).

137 Inserting the values µ Ã and G into formula (4), the following values for Cs specific activity for different types of radwaste are obtained:

SRW Type Design Formula -6 “Water” m    exp, Ci/kg

-6 “Concrete” m     exp, Ci/kg

-6 “Metal” m    exp, Ci/kg

,QWKHVHIRUPXODHWKHH[SRVXUHGRVHUDWH exp must be expressed in units of mR/h.

Taking into account the relatively small range of coefficient values in the above formulae (less than 10% variation) and in order to simplify the estimation a single formula for all the above mentioned waste types has been adopted:

-6 m     exp , Ci/kg, ( 5 )

ZKHUH exp, mR/hour.

1RWH 7KLV VLPSOLILFDWLRQ LV SRVVLEOH RQO\ DV D UHVXOW RI WKH KLJK HQHUJ\ RI WKH SKRWRQ emitted by 137Cs, and the insignificant deviations in the elementary content of the various solid radwaste types listed above. For other types of radioactive waste, for example lead scrap, Formula (5) cannot be applied.

The activity of 137Cs, contained in the whole waste batch is defined by the formula:

-6  Ci     M  exp,

ZKHUH ZDVWHPDVVNJ exp - exposure dose rate on the waste surface, mR/hour.

The radionuclide composition of Chernobyl radioactive waste (year 1996) is as follows, %:

90Sr 20.7 - 29.12 years 134Cs 1.1 - 2.062 years 137Cs 46.6 - 30.0 years 238Pu 0.23 - 87.74 years 239, 240Pu 0.64 - 6537 years 241Pu 30.0 - 14.4 years 241 Am 0.65 - 433 years

Note: The radionuclide composition of the waste, following processing by water (slime, silt, bottom soils) can differ from the above.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page C-2 Therefore, to estimate the total waste activity for all the radionuclides one can use the following formula:

    exp

where ZDVWHWRWDODFWLYLW\LQWKHZDVWHEDWFKP&L PDVVRIWKHZDVWHEDWFKWRQQHV exp - gamma-emission exposure dose rate from the solid radioactive waste, mR/h.

For the assessment of the activity of the other radionuclides, the following formulae can be used:

Sr90     exp α     exp where 90 Sr90 - Sr activity, mCi; 241  α - alpha-emitting transuranic radionuclide activity (i.e. without Pu), mCi;  ZDVWHPDVVWRQQHV exp - exposure dose rate, mR/hour.

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Radionuclide specific activity, Bq/g Sample # Cs-137 Cs-134 Sr-90 Pu-238 Pu-239,240 Co-60 Eu-154 Eu-155 Am-241 Sb-125 Mn-54 1 1.92E+02 3.84E+00 1.40E+02 5.57E-01 1.23E+00 5.95E-01 2.07E+00 2.32E+00 1.56E+00 2 3.03E+02 6.06E+00 1.73E+02 8.79E-01 1.88E+00 6.67E-01 3.70E+00 2.85E+00 4.45E+00 3 1.41E+02 1.41E+00 4.23E+00 4.37E-01 8.18E-01 1.13E-01 9.59E-01 3.67E-01 8.18E-01 4 4.44E+02 4.44E+00 6.30E+02 2.75E+00 5.91E+00 7.55E-01 8.52E+00 3.69E+00 9.63E+00 3.42E+00 5 2.62E+01 2.62E-01 3.22E-01 1.86E-01 2.59E-01 6 7.53E+01 7.53E-01 8.58E-01 5.27E-01 7.83E-01 7 7.28E+01 7.28E-01 4.44E+01 4.44E-01 8.52E-01 4.00E-01 4.08E-01 1.16E+00 8 1.67E+01 1.67E-01 3.56E+01 3.52E-01 5.91E-01 2.09E-01 2.20E-01 8.65E-01 9 1.70E+01 1.70E-01 1.67E+01 6.97E-02 1.63E-01 1.41E-01 9.52E-02 1.05E+00 10 5.07E+00 1.01E-01 4.06E+00 1.62E-02 4.82E-02 5.32E-02 3.15E-01 11 2.63E+00 1.84E-01 1.61E-01 1.47E-02 12 1.67E+02 2.00E+01 7.30E+00 13 8.88E+00 1.42E+00 1.49E+00 1.69E-02 14 8.88E+00 8.88E-01 2.78E-01 15 4.44E+00 3.44E+00 16 17 1.52E+02 1.52E+00 3.34E+01 1.52E-01 4.86E-01 2.28E-01 2.81E+00 1.16E+00 18 5.92E+02 5.92E+00 1.95E+00 5.56E+00 5.33E-01 7.04E+00 2.31E+00 7.76E+00 2.31E+00 19 6.40E+00 7.68E-01 2.37E-02 6.40E-03 4.83E-01 7.36E-02 3.85E-01 7.87E-02 4.14E-01 7.68E-03 20 3.30E+01 3.30E-01 2.38E+01 1.39E-01 3.25E+00 1.25E-01 3.23E-01 21 3.30E+01 3.30E-01 2.61E+01 2.71E-01 6.20E-01 1.65E-02 4.69E-01 2.31E-01 5.61E-01 1.39E-01 22 7.10E+00 7.10E-02 5.18E+00 2.98E-02 6.25E-02 5.40E-02 5.61E-02 4.97E-02 9.87E-02 23 4.30E-01 4.30E-03 6.67E-01 1.03E-03 3.96E-03 1.94E-03 24 1.10E+00 6.14E+00 25 3.20E+01 3.49E+01 26 1.40E+01 1.40E-01 6.16E+00 4.76E-02 1.09E-01 1.13E-01 1.01E-01

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page D-1 Radionuclide specific activity, Bq/g Sample # Cs-137 Cs-134 Sr-90 Pu-238 Pu-239,240 Co-60 Eu-154 Eu-155 Am-241 Sb-125 Mn-54 27 3.40E+01 3.40E-01 1.05E+01 7.14E-02 1.36E-02 3.16E-01 3.88E-01 28 5.20E+00 5.20E-02 2.29E+00 3.12E-03 8.32E-03 29 7.50E+01 7.50E-01 9.83E+01 4.05E-01 1.59E+00 30 1.30E+02 1.30E+00 1.30E+00 1.73E+00 2.60E-02 1.73E+00 31 2.90E+01 4.35E+00 32 1.10E+01 1.10E-03 3.30E-03 2.20E-03 33 1.10E+01 5.72E+00 6.60E-03 34 2.30E+01 1.20E+01 3.13E-01 35 3.10E+01 3.10E-01 2.29E+01 1.61E-01 3.50E-01 4.19E-01 36 6.20E-01 6.20E-03 3.41E-01 1.98E-03 5.58E-03 5.83E-03 6.39E-03 37 2.20E+01 2.20E-01 2.20E-01 4.18E-02 5.72E-02 2.86E-02 1.98E-02 1.32E-02 7.70E-02 38 8.80E+00 8.80E-02 7.30E+00 4.14E-02 1.40E-01 5.72E-02 2.30E-01 39 3.10E+01 3.10E-01 2.70E+01 8.37E-02 1.71E-01 1.21E-01 2.79E-01 1.30E-01 3.41E-01 40 1.40E+01 1.40E-01 1.40E+01 1.11E-01 2.30E-01 41 1.10E+01 1.10E-01 4.40E+00 3.41E-02 9.79E-02 42 7.60E+00 7.60E-02 1.98E+00 9.88E-03 2.74E-02 1.52E-02 8.66E-02 4.79E-02 43 2.20E+00 2.20E-02 2.90E+00 4.40E-04 9.90E-03 44 1.10E+02 1.60E+02 2.09E-01 5.61E-01 8.58E-01 45 4.60E+01 4.60E-01 1.79E+01 9.20E-02 2.39E-01 5.52E-01 46 1.80E+01 1.80E-01 7.92E+00 7.02E-02 1.69E-01 1.49E-01 1.60E-01 47 3.50E+01 3.50E-01 9.00E+01 1.72E-01 3.61E-01 3.40E-01 6.79E-01 48 4.80E+00 4.80E-02 3.12E+00 2.02E-02 4.99E-02 2.02E-02 6.00E-02 49 1.40E+01 1.40E-01 1.20E+01 6.44E-02 1.50E-01 2.70E-01 50 4.10E+01 4.10E-01 1.89E+01 3.40E-01 8.12E-01 4.51E-01 51 4.20E+01 4.20E-01 3.11E+01 3.49E-01 7.39E-01 7.52E-01 52 2.70E-01 4.51E-01 2.00E-03 53 1.10E+01 1.10E-01 7.26E+00 3.96E-02 1.10E-01 1.98E-02 1.00E-01 1.60E-01 54 2.20E+01 2.20E-01 2.20E+01 9.02E-02 1.89E-01 1.98E-02 2.09E-01 4.51E-01 55 4.30E-02 7.01E-02 56 3.60E+02 3.60E+00 2.41E+02 2.70E+00 5.51E+00 4.50E+00 57 2.80E+02 2.80E+00 2.80E+01 2.24E-01 4.48E-01 4.76E-01 58 9.90E+00 9.90E-02 7.82E+00 1.20E-01 2.90E-01 3.30E-01

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page D-2 Radionuclide specific activity, Bq/g Sample # Cs-137 Cs-134 Sr-90 Pu-238 Pu-239,240 Co-60 Eu-154 Eu-155 Am-241 Sb-125 Mn-54 59 6.10E+01 6.10E-01 4.21E+01 4.82E-01 9.52E-01 8.91E-01 60 4.30E+01 4.30E-01 5.59E+01 3.61E-01 8.69E-01 61 2.20E+02 2.20E+00 1.61E+02 1.30E+00 3.10E+00 3.10E+00 62 7.40E+01 7.40E-01 7.10E+01 63 1.90E+02 1.90E+00 1.50E+02 3.50E+00 8.36E-01 4.60E+00 64 4.10E+00 4.02E-02 7.01E-02 65 6.80E+00 6.80E-02 3.40E+00 5.98E-02 66 6.60E+01 6.60E-01 6.27E+01 4.22E-01 1.20E+00 1.10E+00 67 6.10E+02 6.10E+00 2.81E+02 1.53E+00 4.21E+00 6.10E-01 4.27E+00 4.03E+00 68 4.80E+01 4.80E-01 3.31E+01 4.22E-01 69 2.70E+02 2.70E+00 2.51E+02 7.02E-01 2.59E+00

$YHUDJH ( ( ( ( ( ( ( ( ( 0D[LPXP ( ( ( ( ( ( ( ( ( Minimum 4.30E-02 4.30E-03 7.01E-02 4.40E-04 2.00E-03 1.03E-03 3.96E-03 1.94E-03 2.20E-03

Number of 68 57 57 47 48 22 36 18 45 4 3 Samples

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According to the methods [UDK NPO Pripyat] the specific activity of radioactive waste is estimated by following formula:

  

where – activity, mCi; – mass, tonnes; - exposure dose rate, mR/hour.

Applying the above formula it is possible to estimate the specific activity in Bq/g:

4 4>%TJ@     >5KRXU@

According to the acceptance criteria the disposal of waste with exposure dose rates up to 1R/h at Buryakovka is authorised. Hence the upper limit on the radioactive waste specific activity is:

4 4>%TJ@   Bq/g = 111000 Bq/g.

According to the acceptance criteria the activity of alpha-emitting radionuclides must not exceed 2 % of total activity. This corresponds to an upper limit for the specific activity for alpha-emitting radionuclides of 2200 Bq/g .

For the specific activity of alpha-emitting radionuclides not to exceed 400 Bq/g (IAEA recommendation), the limit on exposure dose rate should be revised as follows:

Using the fact that for Chernobyl wastes the activity of transuranic elements is approximately 1.6% of the total activity,

4 4[Bq/g] = 400x100/1.6 = 11.1 x 10 x P [R/h]

P = 220 mR/h

Reference: UDK NPO Pripyat. Temporary guidance on the measurement and estimation of the total activity of SRW which is accepted at PZRO Buryakovka.

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1PZRO 30 km Reception of 900 1km* Waste stored in 0,02-3,5 ----- 2 093,4 1.40.04 Ã  65 692 “Buryakovka” Exclusion Zone low active storage facilities of 0,2-35 Ã  Ã  around ChNPP and medium trench type with active wastes clay shield and soil since January diking** 20, 1987 till December 01, 1998 2 PZRO “Podlesny” "-" In the 60 "-" Waste stored in the 0,16-9,5 ----- 59,3 "-" Ã  70 000 preservation above-ground 1,6-95 Ã  Ã  status since storage facilities, December 20, constructed of 1986 till reinforced concrete December 05, 1988 3PZRO "-" Preserved 20 "-" Waste stored in the 0,03-3,4 ----- 50,1 1.40.04 Ã  12 727 “Kompleksny” since October unfinished ChNPP 0,3-34 Ã  Ã  10, 1986 till Stage III storage December 10, facility for low- 1988 level waste, in tanks with a clay shield and soil diking 4PVLRO “Staraya"-" 1 250 "-" Waste stored in 0,1-340 ----- 56,4 1.40.04 Ã  30 444 Stroybaza” trenches with soil 1-3 400 Ã  Ã  filling and diking

5PVLRO “Novaya"-" "-" 1 220 "-" "-" 0,2-10 ------32,0 1.40.04 Ã  5 000 Stroybaza” 2-100 Ã  Ã  6PVLRO “Ryzhy"-" "-" 2 275 "-" "-" 0,3-100 ------90,2 1.40.04 Ã  13 000 Les” 3-100 Ã  Ã 

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page F-1 Disposal Location Period of Occupied area, thousand Storage conditions Dose rate in Expenditures for storage Stored (disposed) waste characteristic disposition m2 control area, (thousand Urkainain and storage mR / hour, Hryvnas ) operation µSv / hour since 01.01.1997 regime till 01.12.1998 Storage, Control area Capital Annual Radioactive Waste quantity Activity, disposal investments operation wastes type tonnes/m3 Ci/Bq carrying costs code

7 PVLRO “Stantziya "-" "-" 1 280 "-" "-" 0,25-80 ------6,4 1.40.04 Ã  1 000 Yanov ” 2,5-800 Ã  Ã  8 PVLRO “Neftebaza” "-" "-" 700 "-" "-" 0,15-9,0 ----- 19,83 1.40.04 Ã  1 672 1,5-90 Ã  Ã  9PVLRO "-" "-" 880 "-" "-" 0,1-1,1 ------38,0 "-" Ã  5 000 “Peschannoe Plato” 1-11 Ã  Ã  10 PVLRO "-" "-" 1 250 "-" "-" 0,02-0,20 ------24,8 "-" Ã  900 “Kopachi” 0,2-2,0 Ã  Ã  11 PVLRO “ Pripyat” "-" "-" 700 "-" "-" 0,1-6,0 ------103,57 "-" Ã  700 1,0-60 Ã  Ã  12 PVLRO "-" "-" 60 "-" "-" 0,02-0,5 ------32,8 "-" Ã  100 “Chistogalovka” 0,2-5,0 Ã  Ã  13 ChNPP Stage III "-" "-" 24 "-" SRW are stored in 0,03-3,2 ------17,6 1.41.01 Ã  0,2 Discharge Canal canal made of 0,3 *** Ã  Ã  reinforced concrete, clipped by banking TOTAL 10 619 2 624,4 Ã  206 235,2 Ã  Ã 

NOTES: 1. Waste quantity, type, activity category data are presented according to PZRO “Buryakovka” waste storage record results and PZRO Kompleksny, 4. ** According to the design project gloss 86-012-82-2 of the All-Russian PVLRO “Neftebaza” survey. As to the other storage facilities only Research and Design Institute for Power Technology the possibility of evaluation data are presented. laying height buildup up to 6 m at PZRO “Buryakovka” is allowed. This 2. Fissionable radioactive waste decay in the storage facilities were not taken will make possible volume extension in the trenches up to 23 000 m3 and into account in the Table. WKHÃ H[WHQVLRQÃ RIÃ JHQHUDOÃ QHWÃ VWRUDJHÃ YROXPHÃ XSÃ WRÃ Ã Ã Ã Ã ZKLFK 3. * SPORO-85 requirements as to the control area organization around waste corresponds to the real situation. storage and disposal points (sections 2.4, 2.5) are identical to the “Law for 5. *** Water total activity in the canal as for Strontium and Plutonium is 2.7 the Territory Subject to Radionuclide Contamination Legal Regime …” E-9 Ci/L with the maximum permissible value 5.8 E-10 Ci/L, and due to (including ChNPP 30 km zone) requirements. The latter are observed. this fact the water can be classified as low-level LRW.

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6XPPDU\ General geological and hydrogeological conditions in the Chernobyl NPP Near Zone, where the main dumps containing radioactive waste are located, are described within this report. A description of the network of monitoring wells, which is designed for the monitoring of the situation in the whole region and at specific sites, is given. Data obtained relating to groundwater contamination for the Sites of Temporary Radioactive Waste Storage (PVLROs), the Radioactive Waste Disposal Sites (PZROs), the ChNPP Industrial Zone and the Unit Shelter are summarised within the report.

The key findings are summarised below.

The groundwater is contaminated with radionuclides throughout the ChNPP Near Zone area. Strontium-90 is spreading faster than other radionuclides. In a number of cases the waste dumps, and PVLROs in particular, are obvious sources of groundwater contamination.

The progressive contamination of groundwater with Strontium-90 occurs at the PVLROs Ryzhy Les, Stroybaza, Neftebaza, and Stantziya Yanov. Strontium-90 with maximum specific activities of up to 30000 Bq/l, measured during the surveys performed from 1992 to 1999, can be found under the waste trenches. Downstream from the trenches there are ‘hotspots’ of groundwater contamination, with the Strontium-90 concentration in them varying from ~100 to ~1000 Bq/l. Strontium-90 migration within the groundwater occurs in the horizontal direction at a rate of 1 meter per year. At the present time the contamination has spread some 10 – 15 m from the trenches. Beyond the contaminant plumes the Strontium- 90 concentration is around 10 to 100 Bq/l, due to vertical radionuclide transport from the contaminated surface and subsurface soil layers.

Where the topsoil has not been removed during decontamination work, radionuclide concentrations in the upper sections of the aquifer do not exceed ~0.1 – 1 Bq/l.

At the present time there is no evidence of radionuclides leaking from PZROs Podlesny and Buryakovka. The radionuclide concentrations in the monitoring wells, located near these disposal sites, do not differ significantly from the “background” levels. However, these hydrogeological monitoring systems have a number of drawbacks and we cannot be confident that the waste is safely isolated from the environment.

For PZRO Kompleksny radionuclide leakage into the groundwater is present, resulting from the underflooding of waste tanks by groundwater and rainwater infiltration through the soil cap. However, the spread of contamination is not significant yet, due to the small groundwater gradients. The maximum measured concentration of Strontium-90 at the PZRO boundaries was 310 Bq/l (in 1996).

Groundwater contamination by Strontium-90 of up to 3800 Bq/l and by Caesium-137 of up to 200 Bq/l (in 1998) can be observed within the ChNPP Industrial Zone, especially around Unit 4. In addition to radionuclide contamination, lead, nickel, manganese, and iron were detected

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-1 in the groundwater. The maximum permissible groundwater concentrations according to Ukrainian requirements were exceeded.

The current hydrogeological monitoring system within the ChNPP Near Zone, performed by the State Enterprise RADEK under the framework of Exclusion Zone radiological monitoring, has a number of considerable drawbacks. Poor design and location of the monitoring wells represent the most serious problems and need to be improved.

+*HRORJLFDO&RPSRVLWLRQDQG+\GURJHRORJLFDO&RQGLWLRQVLQ6XUYH\HG$UHD The unconfined aquifer, under the ChNPP Near Zone soil surface, was defined as pliocene- quaternary sediment (sands, loamy sand). The aquifer thickness varies within the range of 15 – 30 meters. Transmissivity varies between 100 – 400 m2/day on the river terrace and 40 – 100 m2/day in the area of watersheds. In the watershed area, water levels vary by 0.5 – 1.0 m over the year, and in the flood plain areas they vary by 1.0 – 2.0 m and more. The rate of groundwater recharge from precipitation was estimated as 40 – 200 mm/year, with a precipitation rate of approximately 600 mm/year. The waters are mainly calcium and magnesium bicarbonate, with a mineralisation value of 0.1 – 0.5 mg/l. The groundwater predominantly discharges into the river Pripyat and surface water bodies located in the river flood plain (Figure H1).

The underlying aquitard comprises marls of medium paleogene Kiev suite (P2kv). Below this aquitard there is a confined aquifer in the Eocene sediments /P2 EþNQ 7KHLPSHUPHDEOH sediments lie at a depth of 20 – 30 m in the floodplain areas and down to 90 m in the watershed areas. This layer is 10 – 20 m thick. The conductivity of marl clay was estimated to be in the range of 2.5×10-4 – 2×10-2 m/day. The confined aquifer in the eocene sediments, represented by glauconitic quartz arenaceous, supplies water to Pripyat town and ChNPP. Below the confined aquifers lie saturated cretaceous sediments. The geology was studied to the level of Jurassic clay at the depth of approximately 220 m [1]. Figure H2 illustrates the geological cross-section through the ChNPP Near Zone. Figure H1 shows the location of the above cross-section.

Table H1 shows the hydrogeological conditions in the vicinity of the waste dumps. PZROs “Buryakovka” and PVLRO “Chistogalovka” are located in the river Uzh and river Pripyat watershed area. Therefore, they are relatively remote from the discharge areas. PVLRO “Neftebaza” is located on the flood plain in immediate proximity to the river Pripyat and the Pripyat Inlet. Thus, a number of PVLRO “Neftebaza” trenches located in the flood plain area are flooded by groundwater and periodically flooded by surface water during spring (on average once every four years). The other waste dumps are located on the first terrace above Pripyat’s floodplain.

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Location Lithology of Ground Depth of the Flooding by Flooding by Groundwater Conducti- Groundwater flow Distance to saturated and elevation ground- ground-water surface flow vity, discharge area discharge unsaturated (above sea water table, waters gradient, m/day area, horizons level), m m m/m m ChNPP Sand, crushed 115 4 No no 0.001 1-10 Azbuchin Lake 1500 Industrial stone, concrete, Zone sand, loamy sand PVLRO

Ryzhy les Sand, loamy 113 2 Yes no 0.002 1-10 The Pripyat Inlet 1000 sand Yanov Sand, loamy 113 3 Yes no 0.002 1-10 The Pripyat Inlet 1200 sand Stroybaza Sand, loamy 114 3 No no 0.001 1-10 The Pripyat Inlet 1000 sand Neftebaza Sand, loamy 107 (flood 1 (flood yes (flood yes (flood 0.004 (flood 0.1-10 The Pripyat Inlet, 0 sand plain), plain), plain), plain), plain), the Pripyat river 115 (terrace) 6 (terrace) no (terrace) no (terrace) 0.008 (terrace) Peschannoe Inwashed sand, 113 7 No no 0.002 5-20 The Pripyat river 500 Plato sand, loamy sand Pripyat Sand, loamy 113 6 No no 0.002 1-10 The Pripyat Inlet 1300 sand Kopachi Sand, loamy 112 2 ? no 0.001 1-10 Stream Borschi, 0 sand Stream Rodvino Chistoga- Sand, loamy 140 7 - 14 ? no 0.001 0.1-10 Stream Rodvino 2000 lovka sand, clays

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-5 Table H1 Continued Location Lithology of Ground Depth of the Flooding by Flooding by Groundwater Conducti- Groundwater flow Distance to saturated and elevation ground- ground-water surface flow vity, discharge area discharge unsaturated (above sea water table, waters gradient, m/day area, horizons level), m m m/m m Podlesny Sand, loamy 115 8 No no 0.002 0.1-10 The Pripyat Inlet 500 sand Kompleksn Sand, loamy 116 5 Yes no 0.0001 1-10 Cooling pond 250 y sand Buryakovk Sand, loamy 140 16 No no 0.0005 0.1-10 The river Uzh 2000 a sand, clays (feeder)

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-6 +*URXQGZDWHU5DGLRDFWLYH&RQWDPLQDWLRQ0RQLWRULQJLQWKH([FOXVLRQ=RQH +6WDWH(QWHUSULVH³5$'(.´0RQLWRULQJ3URJUDPPH The State Enterprise of Regional Monitoring and Dosimetric Control (SE “RADEK”) implements the basic programme for groundwater radioactive contamination monitoring in the Exclusion Zone.

At the present time SE “RADEK” monitors approximately 180 wells. The borehole monitoring network was developed in several stages. Figure H3 shows monitoring wells of the first stage, constructed before 1990 (series “N” and “K”). Often the location of these wells was defined by the road proximity. In many cases the location of the waste and the groundwater flow direction were not taken into account. The significant drawback in the design of boreholes, set up between 1986 and 1990, is that their filter is 12-meter deep. Due to this, the concentration of the samples is an average over a wide range of depths.

At the next stage of construction of the borehole monitoring network in the Near Zone, new boreholes were drilled and some obsolete wells were closed. During 1995 – 1999 a number of new wells were constructed under the supervision of IGS (Figure H4). Their characteristic features are as follows:

- filter depth between 1 and 2 m; - wells, grouped in clusters, in order to test different aquifer depth intervals; - source term location and the groundwater flow direction were taken into account.

The groundwater parameters monitored by the State Enterprise “RADEK” are: groundwater level, concentration of Caesium-137 and Strontium-90, and estimates of the concentration of Plutonium and Americium for selected samples. The frequency of water sampling varies from monthly to quarterly.

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2EVHUYDWLRQZHOOVPLQGHSWK IRUIUHHDTXLIHU upper layer)  Chistogalovka Ridge observation wells (for free aquifer upper layer, from 6 to 20 m in depth) Observation wells, 20 m in depth (for free aquifer  middle layer)  Observation wells up to 30 m in depth aquifer lower layer)  Observation wells for confined aquifer -streams, canals;

)LJXUH+³5$'(.´PRQLWRULQJERUHKROHQHWZRUNLQWKH&K1331HDU=RQH FRQVWUXFWHGLQ± NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-9 +%RUHKROH0RQLWRULQJ1HWZRUNRIWKH,QVWLWXWHRI*HRORJLFDO6FLHQFHV During 1995 – 1997, under the framework of the hydrogeological activities special programme, the Institute of Geological Sciences (IGS) constructed wells of a simplified design (polyethylene tube, 1 inch in diameter with the stainless steel filter of 30 cm long) at the right- and left-bank areas of the Pripyat river in the Near Zone (Figure H5) [2, 3, 4]. The objective of this work was to obtain new data on the sectors, in which State Enterprise “RADEK” wells were absent or unfit for valid data collection due to ineffectual design. A number of simultaneous measurements of groundwater levels were made at IGS, ChNPP and State Enterprise “RADEK” wells during 1996 – 1999. These activities provided an opportunity to develop a groundwater movement scheme with the help of well survey technologies (Figure H6).

+ +LVWRU\ RI ([SHULPHQWDO 5HVHDUFK LQWR 5DGLRQXFOLGH 0LJUDWLRQ IURP 39/52V During 1992 – 1999 the Institute of Industrial Technologies (Moscow); the Research and Design Institute of Industrial Technologies (RDIIT), the Scientific Research Centre KORO and IGS have implemented geological surveys of radionuclide contamination in groundwater at PVLRO sectors “Ryzhy Les”, “Yanov”, “Neftebaza”, “Peschannoe Plato”, and PZRO “Kompleksny”.

Research into radionuclide migration provided an opportunity to obtain data on groundwater contamination. Data obtained from measurements using hand drilling gave contamination levels appreciably above the “RADEK” observation well results. This was due to the fact that, while hand drilling, the water sampling was performed directly near the trenches within the contaminant plume, whereas the “RADEK” wells at the PVLRO sectors are located at some distance from waste dumps, and therefore measure background radionuclide concentrations in the groundwater.

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During 1995 – 2000, the Ministry of Chernobyl Affairs (later the Ministry of Emergencies) of the Ukraine financed the scientific research programme “Polygon”, which studied radionuclide migration from PVLROs at special experimental areas (“polygons”). Under the framework of this programme, IGS and the Scientific Research Center “KORO” have equipped observation wells at the experimental areas near trench 22 of PVLRO “Ryzhy Les” and near trenches 4 and   RI 39/52 ³1HIWHED]D´ 3UHOLPLQDU\ JURXQGZDWHU contamination surveys were implemented at PVLRO “Stroybaza” [6]. Under the Institute of Nuclear Safety and Protection (IPSN) of France aegis, international radioecological research KDV EHHQ SHUIRUPHG QHDU WUHQFK 22 of PVLRO “Ryzhy Les” since 1998. IGS and the Ukrainian Institute of Agricultural Radioecology also partake in this research. The objective of the project is to study mechanisms of radionuclide migration in order to improve and validate models of radionuclide transfer in the biosphere [7].

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-12 The results of the research, mentioned above, allowed the detailed characterisation of groundwater contamination in the experimental areas near the waste dumps, and the estimation of the parameters relating to radionuclide migration from the PVLROs. The results of research into radionuclide migration from PVLROs are considered below, in Section H5.

+ *HQHUDO &KDUDFWHULVWLFV RI 5DGLRDFWLYH &RQWDPLQDWLRQ RI *URXQGZDWHU LQ WKH9LFLQLW\RIWKH:DVWH'XPSVLQWKH1HDU=RQH +*URXQGZDWHU&RQWDPLQDWLRQLQWKH&K1331HDU=RQH The sources of radioactive groundwater contamination in the Exclusion Zone are fuel particles distributed in the surface soil layers and the waste located at PVLROs and PZROs. Figure H7 shows the 90Sr and 137Cs distribution in the surface soil layer in the ChNPP Near Zone, according to [8]. Radionuclides in the fuel particles were initially insoluble in water, however with time the radionuclides have been converted into more soluble forms [9].

The dissolved radionuclides are transported to the ground aquifer through the aeration zone by atmospheric moisture. The Near Zone aeration zone is composed of sandy sediments and its depth varies from 0 to 10 m (Figure H8). The typical aeration zone depth is 0.5 – 3 m in the flood plain area and 3 – 4 m in the first terrace above the flood plain. The terrace is characterized by ground water infiltration rates of about 80 – 250 mm/year.

Strontium-90 is the most mobile radioactive contaminant. 90Sr mobility can be illustrated by Kd assessments for PVLRO Ryzhy Les, implemented by A. Ol’khovik [9] (Table H2). 137Cs, which has a distribution ratio of 10 – 100 times higher than 90Sr, is a less mobile [11]. The migration characteristics of Plutonium isotopes in the Exclusion Zone are poorly studied, but it is known that normally Plutonium has relatively low mobility in geological environments.

From the monitoring results, groundwater contamination plumes from the PVLROs and the Unit Shelter, and also background contamination levels from contaminated soils, have been identified within the Exclusion Zone. Surface contamination is the cause of groundwater background contamination with 90Sr specific activities of approximately n* 0.1 Bq/l and 137Cs specific activities of approximately n* 0.01 Bq/l. Figure H9 shows the distribution of contamination by Sr-90 in the upper layer of the soil aquifer, according to IGS data [2, 3].

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Same as above 1.3-2.7 72.2 22.1 4.8 0.8 2.1

Fine/ loamy sand 2.7-4.2 70.5 11.0 7.7 10.7 6.3

Light gray sand 4.2-5.8 68.5 15.3 7.3 8.9 4.5

Fine light gray sand 5.8-7.3 81.1 10.4 3.6 4.9 4.4

Same as above 7.3-8.8 85.6 10.4 2.4 1.6 1.9

Fine/ loamy sand 8.8-10.3 59.8 20.0 11.3 8.9 10.1

Fine sand 10.3-11.8 87.3 8.2 2.5 2.0 3

Same as above 11.8-13.3 92.9 5.4 1.2 0.5 1.1

Same as above 13.3-14.8 65.3 22.7 8.6 3.4 4.0

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PVLRO “Ryzhy Les” (see Figure H3) is located on the first terrace above the floodplain along the road leading to the city of Pripyat. In the PVLRO area, the ground surface elevation is 113 – 115 m above the Baltic Sea. Figure H2 shows the generalized geological section through the PVLRO (wells 1/98 and 515 area). The upper layer of the section, up to elevations of approximately 110 m, is represented by fine-grained anemoarenytes. Lower down, up to the first regional aquifuge, the geological section is represented by fine-grained and medium-grained alluvial sands, and in the upper level it is represented by non- homogeneous loamy sand sediments.

An unconfined aquifer within the area of the waste dumps lies at the depth of 0 – 4 m. The nearest surface waters for groundwater discharge from the area, are the Pripyat Inlet (1000 m), the ChNPP horizontal drainage gallery (500 m), and the ChNPP feeder (900 m). The groundwater gradients are 0.001 – 0.004. The filtration coefficients for the fine-grained anemoarenytes and alluvial sands are 3 – 5 m/day, for the medium-grained sands 5 – 15 m/day, and for the loamy sand sediments 0.5 – 1 m/day.

According to the Research and Design Institute of Industrial Technologies (RDIIT) data [5], the majority of the waste dumps in PVLRO “Ryzhy Les” are underflooded by groundwater either seasonally or constantly.

Wells K-14, K-13, 1 N, 2 N, and 3 N were designed for monitoring groundwater contamination at PVLRO “Ryzhy Les” under the framework of the State Enterprise “RADEK” monitoring system (see Figure H3). According to the results of the monitoring, performed from 1993 to the present, in 1 N – 3 N wells the Strontium-90 concentration in groundwater varied from 0 to 2 Bq/l. Nowadays, the Strontium-90 concentration increase can be tracked in the K–13 well (Figure H10).

  )LJXUH+&RQFHQWUDWLRQRI 6UDQG &VLQZHOO.LQWKHYLFLQLW\RI5\]K\/HV 39/527UHQGOLQHVUHSUHVHQWWKHPRYLQJDYHUDJHIRUSRLQWV ³5$'(.´GDWD NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-18 Research into groundwater contamination at PVLRO “Ryzhy Les”, in which hand drilling and specially equipped nets for observation wells were used directly near the waste dumps according to the programme “Poligon”, revealed that groundwater contains Strontium-90 in greater amounts than had been estimated according to “RADEK” observation results. For example, according to the Research and Design Institute of Industrial Technologies research >@ LQ  XQGHU WUHQFK   WKH 6WURQWLXP FRQFHQWUDWLRQ ZDV  %TO DQG DFFRUGLQJ WR  ,*6 UHVHDUFK UHVXOWV >@ XQGHU WUHQFK   WKH PD[LPXP YDOXH IRU Strontium-90 was 20,000 Bq/l. In general, within the area of Strontium-90 migration from the trenches, its concentration value normally varies from a few hundreds to a few thousands Bq/l [6, 7]. Beyond the Strontium-90 migration plumes its concentration in the groundwater is n * 10 – n * 100 Bq/l.

According to State Enterprise “RADEK” and IGS data, Caesium-137 is concentrated in the groundwater in relatively small amounts, normally the value is n * 0.01 – n * 0.1 Bq/l. According to IGS research results, the Caesium-137 concentration in the groundwater under the trenches increases up to n * 0.1 Bq/l, and in the flooded trenches its concentration can be several Bq/l [12].

In the groundwater of “Ryzhy Les” Plutonium isotopes were revealed in the flooded trenches and under the non-flooded trenches. Table H3 summarises the results of the research into Plutonium isotope contamination of groundwater, obtained by various organisations. IGS UHVHDUFKLQWRWKHIRUPVRI3OXWRQLXPLVRWRSHVLQWUHQFK >@UHYHDOHGWKDWWKHQHXWUDO forms of isotopes also can be tracked there (Figure H11). The quantity of neutral forms of isotopes is equal to that of cationic and anionic forms. The presence of neutral and anionic forms points at accelerated migration possibilities for Plutonium isotopes in groundwater.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-19 7DEOH+3OXWRQLXP,VRWRSHV&RQWHQWLQ39/52³5\]K\/HV´*URXQGZDWHU Year of SRW 239+240Pu, 238Pu, Point Organisation Well esti- storage Bq/l Bq/l mation conditions &ODPSWUHQFK  IGS Without 1994 Underflooded 0,42±0,04 0,2±0,02 number &ODPSWUHQFK  IGS Without 1998 Underflooded 5,0±0,7 2,3±0,2 number 7UHQFK  IGS 2/98-igs 1998 Underflooded 0,35±0,04 0,2±0,05 7UHQFK  IGS 3/98- igs 1998 Underflooded <0.001 7UHQFK  IGS 4/98- igs 1998 Underflooded 1,4±0,1 0,8±0,07 7UHQFK  IGS Without 1994 Underflooded 0,58±0,12 0,23±0,05 number 7UHQFK  IGS 1/95-1- igs 1997 Non-flooded 0.05±0,001 0.027±0,002 7UHQFK  IGS 1/95-2- igs 1997 Non-flooded 0.0018±0,00 <0.001 08 7UHQFK  IGS 1/95-3- igs 1997 Non-flooded 0.002± <0.001 0,0008 7UHQFK  IGS 1/95-1- igs 1998 Non-flooded 0,12±0,01 0,065± 0.0008 7UHQFK  RDIIT 1992 0,42 7UHQFK  RDIIT 1992 0,33 7UHQFK  RDIIT 1992 0,15

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PVLRO “Stroybaza” (see Figure H3) adjoins the ChNPP from the Western and from the Southern sides. It is located on the first terrace above the floodplain. The ground surface elevation is 114 – 115 m (Baltic System of Elevation). The geographical section of the area is similar to the PVLRO “Ryzhy Les” section.

An unconfined aquifer lies at a depth of 1 – 4 m. It discharges into the ChNPP drainage gallery, to the Pripyat Inlet and to the ChNPP Cooling Pond feeder. The Pripyat Inlet is within a distance of 600 – 700 m, the feeder and drainage gallery adjoin the disposal. The groundwater gradients are 0.001 – 0.003.

State Enterprise “RADEK” makes groundwater observations at 12 wells in the PVLRO area (see Figures H3 and H4). In the PVLRO groundwater an increase in Strontium-90 concentration was revealed, with the maximum values being estimated for the K-1/1 well (Figure H11). According to State Enterprise “RADEK” data, the groundwater Caesium-137 specific concentrations are n * 0.1 Bq/l.

Also according to IGS research data, groundwater at the PVLRO “Stroybaza” is contaminated with Strontium-90. A water sample, taken near the K-1/1 well in August 1994, contained 250 Bq/l of Strontium-90 [13]. In November 1998 Strontium-90 specific activity in the well located in the North-Western part of the PVLRO (well 5/98 – igs) was measured as 80 Bq/l [5].

To date, detailed investigation into waste dumps at PVLRO “Stroybaza” has not been performed, and therefore the interpretation of the groundwater monitoring data is difficult. It seems possible, that water sampling directly under the waste dumps or adjacent to the dumps in the direction of groundwater movement could reveal higher Strontium-90 concentrations, as compared with the already revealed ones (by analogy with PVLRO “Ryzhy Les”).

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-22 39/521HIWHED]D PVLRO “Neftebaza” is located along the Pripyat Inlet eastern bank (see Figure H3), partially on the Pripyat river flood plain and partially on the first terrace. The flood plain ground surface elevation varies from 108 to 106 m, and in the terrace from 110 – 115 m (Baltic System of Elevation). The flood plain geological section (see Figure H2) is presented by alluvial upper quartenary period sediments, composed of fine-grained and medium-grained sands, and with loamy sands interbeds in the upper layers. On the terrace the geological section is similar to that of PVLRO Ryzhy Les.

An unconfined aquifer lies at a depth of 0 – 3 m in the flood plain and at a depth of 5 – 10 m in the terrace. The groundwater is discharged to the Pripyat Inlet (the Inlet annual water-level marks are approximately 105 m) and to the Pripyat river (in the Northern part of the PVLRO, where the flooding from the Pripyat Inlet takes place) (see Figure H1.). The groundwater gradients are 0.001 – 0.004. The PVLRO Southern part is located in the zone affected by flow from the sewage filtration fields.

The Pripyat Inlet wells, namely K-4, K-5, K-6, and K-7 (see Figure H3), form the State Enterprise “RADEK” monitoring system in the PVLRO “Neftebaza” area. Maximum values of the groundwater Strontium-90 and Caesium-137 specific activities were revealed in the K- 5 well (see Figure H12). The K-5 well is situated not far from the Pripyat Inlet (approximately within a 20 m distance) and, apparently, the Inlet phreatic fluctuation influences the radionuclide concentrations. A general increase in the Strontium-90 concentration can be traced in the groundwater.

Within the framework of the “Polygon” project, the Scientific Research Center KORO has HTXLSSHG VSHFLDO REVHUYDWLRQ ZHOOV LQ WUHQFKHV   DQG RI39/52³Neftebaza”. According to Scientific Research Center KORO data, in 1998 the maximum Strontium-90 FRQFHQWUDWLRQZDV%TOXQGHUWUHQFK DQG%TOXQGHUWUHQFK &DHVLXP VSHFLILFDFWLYLWLHVZHUHDQG%TOFRUUHVSRQGLQJO\8QGHUWUHQFK WKHVXPRI

Plutonium-239 and Plutonium-240 specific activity did not exceed 0.04 Bq/l. )LJXUH+39/52³1HIWHED]D´ZHOO.VSHFLILFDFWLYLWLHVUHJLPH7UHQGOLQHVUHSUHVHQWWKH PRYLQJDYHUDJHIRUSRLQWV 6WDWH(QWHUSULVH³5$'(.´GDWD

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State Enterprise “RADEK” utilizes K-14 and K-15 wells for the monitoring of groundwater contamination in the disposal area. Figure H13 shows that radionuclide concentrations increased during the initial stage of monitoring (1999 – 1991). The possible reason for this fact may be that the initial contamination by radionuclides within the well originated from the ground surface in the course of well boring and mounting.

As in the case with the other PVLROs, the trench survey, implemented with the help of hand drilling, revealed higher concentration of radionuclides in the groundwater compared with the “RADEK” research results. State Scientific Center ROS employees implemented VDPSOLQJ DW WUHQFK   RI 39/52 ³6WDQW]L\D

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PVLRO “Peschannoe Plato” is located in the flood plain between the Pripyat Inlet and the river Pripyat (see Figure H3). The artificial plateau has an elevation of 110 – 114 m (Baltic System of Elevation). It is composed of sand artificially imported from the Pripyat Inlet, and before the ChNPP Unit 4 disaster it was intended for the further extension and development of the city of Pripyat. After the disaster waste was disposed in the area in trenches 1.5 – 2 m deep. The geological section of the area is represented by imported sands, 5 – 6 m deep in the upper layer. The stratum bottom elevation is 105 – 107 m. Beneath the sand is a deposited soil layer. Before the formation of the artificial plateau this soil composed the flood plain surface. The rest of the section is similar to the PVLRO “Neftebaza” flood plain section.

An unconfined aquifer is situated at a depth of 5 – 7 m. The unconfined aquifer formation in PVLRO “Peschannoe Plato” area occurs because of available filtration between the Inlet and the Pripyat river and due to atmospheric precipitation, some which infiltrates into the aquifer. The unconfined aquifer discharges to the river Pripyat. The shortest distance from a waste dump to the river Pripyat is approximately 100 m. The groundwater gradient is approximately 0.002.

In PVLRO “Peschannoe Plato” the groundwater monitoring system has not been developed yet. “RADEK” does not have trenches available within the PVLRO area. There are three IGS observation wells in the PVLRO area, but these wells apparently do not catch groundwater from under the waste dumps, and therefore they cannot be used for monitoring the contamination of groundwater with radionuclides.

According to IGS data [13], in the groundwater under PVLRO “Peschannoe Plato” the maximum activity of Strontium-90 was 1.3 Bq/l (1994). According to Scientific Research Center KORO data, in groundwater under the dumps the maximum activity of Strontium-90 was 10 Bq/l (1999) [15], but this value was obtained as a single observation result and needs verification.

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PZRO “Podlesny” is located along the river Pripyat on the first terrace above the floodplain, beyond the filtration fields (see Figure H1). The ground surface elevation is 113 – 114 m. Figure H14 shows the generalised geological section. The aquifer is composed of alluvial sandy sediments (see Figure H1 and Figure H2). The groundwater table lies at a depth of approximately 5 m. The PZRO is located in the groundwater spread dome area, which is formed due to the filtration fields. The groundwater is discharged to the pools in the floodplain near the Pripyat river, the Azbuchin lake, and partially to the Pripyat Inlet (see Figure H1). The distance to the Pripyat Inlet is approximately 500 m and the floodplain pools are situated at a distance of 100 m and further. The groundwater gradient is 0.02 – 0.05.

Figure H15 shows the observation wells location around the PZRO. The groundwater is monitored through the State Enterprise “RADEK” wells, “NP” series. The wells are 6 – 15.5 m in depth. The filter is 1/0 – 1/3 m long, the filter installation depth interval varies from 3 – 4 m to 13.4 – 14.7 m. Regular monitoring of radioactive contamination of the groundwater has been implemented through 4 NP, 10 NP, 11 NP wells since 1988, through 5 NP well

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-25 since 1990, and through 12 NP and 15 NP wells since 1996. Figure H16 shows the 90Sr and 137Cs results for 10 NP well (Figure H16). The groundwater 90Sr specific activities vary from 0.1 to 1.0 Bq/l. The 137Cs content is 0.01 – 0.13 Bq/l. During 1987 – 1992, high concentrations of 90Sr may be the result of well contamination caused during boring or the result of some human errors while water sampling. In general, there are no evidence of radionuclides from PZRO “Podlesny” entering the aquifer. However, the well location with regard to the disposal location and the fact that the filters are fitted rather deeply, prevents the effective detection of any contamination from the waste storage facility. The results from the wells tend to reflect radionuclides arising from the filtration fields situated upstream.

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PZRO “Buryakovka” is located within a glacial moraine at 5.4km to the south of the village of Buryakovka. The ground surface elevation is 135-140 m. Sediments are represented mainly by fine sands with layers of clay and loam. The summarised geologic record is provided in Figure H17. The unconfined aquifer is at a depth of 14-18m, and extends to 60 m depth. Groundwater beneath the PZRO discharges to the Uzh River (the stream of Stechanka), which is located at a distance of 2km approximately. The infiltration rate is about 40 – 60 mm/year [13,16].

At the PZRO site there are 132 observation wells drilled around the perimeter of the facility. Groundwater is monitored at 7 wells of the State Enterprise “RADEK”, “B” Series, the location of which is presented in H18. The wells are 20 m deep, the filter is 1m long, and the filter installation depth is 18-19m. Regular monitoring of radionuclide concentrations in groundwater has been performed in the wells 5B, 22B, 35B, 45, 53B since 1989, in the well 65B since 1990, in the well 14B since 1994, and in the well 123B from 1991 to 1993. In compliance with the Regulations, 90Sr and 137Cs composition are monitored quarterly, the groundwater level is monitored quarterly, and 239,240 Pu and 241Am are monitored annually.

The results of 90Sr and 137Cs concentration, performed at the well 5B are presented in Figure H19. 90Sr specific activities are about 1,5 Bq/l, and 137Cs specific activities are within the range 0.01 –0.1 Bq/l. The peak values of 90Sr and 137Cs specific activities may be explained by faults in the water sampling technology. There is no evidence of the transfer of radionuclides from the waste trenches to the aquifer.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-32 3=52³.RPSOHNVQ\´ PZRO “Kompleksny” is located on the man-made island, which is surrounded by the Chernobyl NPP channels on one side and by the Cooling Pond on the other (see FigureH1). Ground surface elevation is 114 – 115m. The geological section shows sand sediments with inclusion of clays and loams. It is similar to the geological section at PVLRO “Ryzhy Les”. The hydrogeological conditions at PZRO “Kompleksny” are characterized by stagnant water- flow. The groundwater table depth is 2.4-4.5 m. The waste repository is flooded by groundwater to a height of 0.7 – 0.5m above the base. The groundwater flow from the southwest to the northeast has gradients of 0.0008 up to 0.0001m/m [17]. The groundwater is discharged into the Cooling Pond, which is located at a distance of 400 m approximately. The surveys of the groundwater at the PZRO “Kompleksny” are performed at 15 wells by the State Enterprise RADEK. The well layout is provided in )LJXUH H20. The wells are 8-10 m deep, the filter is 1.0-1.5m long, and the filter depth is from 5.1-6.6 m up to 8.0-9.0 m. Regular monitoring of the radionuclide composition of the groundwater has been carried out at wells 4-III, 6-III, 8-III, 14-III, 15-III since the year 1989, and at well 13 since 1993. In accordance with the Regulations, the 90Sr and 137Cs concentration, and groundwater level are monitored quarterly and 239+240Pu and 241Am are monitored once a year.

The results of the monitoring performed by the State Enterprise RADEK as to 90Sr and 137Cs concentration in the groundwater in the 14 III well are shown in )LJXUH H21. Strontium-90 concentration varies within the range 1 – 2 Bq/l; caesium-137 concentration within the range 0.05 – 0.01 Bq/l. In the water samples taken by the Scientific and Technical Centre KORO specialists in 1996 directly at the edge of the waste disposal site, 90Sr specific activities of up to 310 Bq/l and 137Cs specific activities of up to 6.7 Bq/l were measured [17]. In the vicinity of the PZRO, the groundwater filtration is slower due to small groundwater gradients. In accordance with the estimates of STC KORO, in 300 years strontium-90 movement will be limited to 100 m at the depths of up to 2-3 m. Thus the location of observation wells at a significant distance from the PZRO (10-20 m) and the depth of filter installation (2-4m lower than the groundwater level) do not allow the reliable detection of radionuclide migration from the PZRO [17].

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-35 +6XPPDULVHGVXUYH\UHVXOWVRIJURXQGZDWHUFRQWDPLQDWLRQDWWKH39/52VDQG 3=52V The Table H4 summarises the monitoring results of groundwater contamination in the vicinity of the waste dumps, according to SE RADEK data. For comparison, Table H5 gives data from the surveys performed by the Research and Design Institute of Industrial Technology (NIPIPT), by the Institute of Geology Sciences, and by the Scientific and Technical Centre “KORO”. These surveys were performed using hand-drilling equipment allowing sampling to be performed directly beside the waste trenches, compared to the RADEK monitoring which was performed using wells located often at some distance from the dumps. The survey results gave higher values of radionuclide specific activity in groundwater that those obtained at the State Enterprise RADEK specified network of wells.

The significant discrepancy of the RADEK data with the data obtained by the Research and Design Institute of Industrial Technology (NIPIPT), the Institute of Geology Sciences, and the Scientific and Technical Center “KORO” surveys can be explained by the following factors:

- imperfect construction of RADEK observation wells (many of the wells have 12m- long filter, which causes water samples’ averaging over a large depth interval), and - poor location of wells, and improper depth of filter installation (too deeply installed filters which do not allow monitoring of the upper part of the aquifer, which is the first target for contamination due to migration from the waste dumps).

The data provided show that the current system of hydrogeological monitoring in the vicinity of waste dumps within the Chernobyl Near Zone, if implemented under the RADEK radiological monitoring program of the exclusion zone, provides unreliable monitoring of radionuclide migration from the dumps, and is to be upgraded.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-37 7DEOH+'DWDRQ*URXQGZDWHU&RQWDPLQDWLRQDWWKH39/52VDQG3=52VREWDLQHGDVWKHUHVXOWRIVXUYH\V KDQGGULOOLQJRILQYHVWLJDWLRQ ZHOOVVXUYH\GDWDREWDLQHGDWSLORWVLWHV Maximum Radionuclide Concentration in Reference to Radioactive Disposal Survey Date Organization that Performed Survey Groundwater near Disposal Areas, Bq/l Survey Report Waste Interim Number Localization Point Strontium- Caesium- Plutonium 90 137 Isotopes (239+240) Ryzhy Les  1992 Research and Design Institute of Industrial 3 600 Unavailable 0.42 [5] Technology Ryzhy Les  1992 Research and Design Institute of Industrial 30 000 Unavailable 0.33 [5] Technology Ryzhy Les  1992 Research and Design Institute of Industrial 14 000 Unavailable 0.15 [5] Technology Ryzhy Les  1998 Institute of Geology Sciences 16 000 0,3 0.18 [6] * Ryzhy Les % 1998 Institute of Geology Sciences 2700 350 5,0 [12] Stantziya Yanov  1995 KORO, State Scientific Center ROS 3 990 Unavailable Unavailable [14] Neftebaza -4 1998 KORO 613 0,4 0.039 [15] Neftebaza ± 1998 KORO 274 0,3 <0.001 [15] Stroybaza Sector 1.5 1998 Institute of Geology Sciences 102 0,5 0.011 [6] Sand Plateau Institute of Geology Sciences 1,3 - - [13] Kompleksny 1996 KORO 310 6,3 <0.001 [17] * Trench No.4 was flooded by groundwater; water samples were taken directly from the trench containing waste

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-38 +  +\GURJHRORJLFDO &RQGLWLRQV DQG &RQWDPLQDWLRQ RI *URXQGZDWHU ZLWKLQ WKH &KHUQRE\O,QGXVWULDO=RQH ++\GURJHRORJLFDO&RQGLWLRQV Within the Chernobyl Industrial Zone, there are two aquifers in the zone of active water flow: in the pliocene overburden sediments (unconfined) and in the eocene (confined) sediments. The aquifers are divided by water-resistant marls of the Kiev series eocene. [18,19]. The summarized geological section is provided in Figure H22.

During the remediation work performed following the 1986 accident, the original soil surface within the Chernobyl Industrial Zone was covered with sand, gravel, rubble and other materials to a total thickness of up to 3 m. At the Unit Shelter, this man-made layer thickness is up to 6 m.

The Chernobyl NPP area is located in the region of groundwater flow from the Chistogalovka bed (feed area) to the floodplain water basin of the Pripyat River (discharge area, see Figure H1). The filtration factor of the water-bearing strata of the unconfined aquifer varies greatly from 1 to 20 m/day. The groundwater gradient with minimum values of 0.0005 near the Chernobyl Units III and IV increases up to 0.002 near the discharge areas. Actual rates of groundwater flow do not exceed 20 –30 m/year [18,19].

The detailed layout of hydroisohypse within the Chernobyl Industrial Zone is presented in Figure H23. The direction of the groundwater flow within the Chernobyl Industrial Zone is formed under the influence of: the cooling-pond, the Azbuchin Lake, the Pripyat Inlet, the filtration fields, drainage systems, and leakages from water service lines. Within the Unit Shelter area, the direction of the groundwater flow undergoes minor changes, and the water flow can be characterized as follows:

- filtration direction from southwest to north, northeast; - groundwater gradients of 0.0008-0.0012 m/m; - rate of groundwater flow is up to 30 m/year.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-42 +*URXQGZDWHU0RQLWRULQJ6\VWHP Groundwater monitoring (Figure H24) at the Chernobyl NPP Industrial Zone and the adjacent DUHDLVSHUIRUPHGDWWKH6WDWH(QWHUSULVH5$'(.ZHOOV 6HULHV &KHUQRE\O133 3 DQG66HULHV DQGWKH8QLW6KHOWHU *16HULHV :HOOVRI6HULHV³6´DUHGHVLJQHGIRU tracking the groundwater contamination. The well filters of 2m length are located at 13-15 m depths from the surface. The wells of “P” Series are designed for the unconfined water level observation. Their filters of 3.5m length are located at 10.5-14m depth. The well filters of 6HULHV *1DUHPORQJDQGDUHORFDWHGDWPGHSWKIURPWKHVXUIDFH3DUWRIWKH6HULHV A wells are located at a greater depth, the filter is 14-25m long [18].

The most comprehensive observation data (since 1988) on the groundwater level is available for wells of series P, but these are wells designed for groundwater level control. The majority of the wells that are located near the Unit Shelter have been regularly monitored since 1994, and all of the wells have been regularly monitored since 1997. The data on the unconfined water level in the Chernobyl NPP area are provided in Figure H25. The groundwater levels undergo periodic changes under the influence of climatic peculiarities in a specific year, particularly apparent are the seasonal periods of rise (winter-spring time), and fall (summer- autumn time). The amplitude of seasonal variations of groundwater levels is not greater than 0.8m. Alongside the seasonal variations of groundwater levels, one can point out the cyclic periods of dominant rises and falls of the total amplitude 1.5-2m [18,19]. Data on the monitoring schedule are provided in the Table H6.

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Soil aquifer contamination by 90Sr and 137Cs in the year 1995 is provided in FigureH26 [18, 19]. Against the background level of groundwater contamination by 90Sr of 2-6 Bq/l, near the Unit Shelter areas were detected with higher concentrations of more than 100 Bq/l (see Figure H26b). The corresponding concentrations of 137Cs at these locations are shown in Figure H26 . The location of the areas of high radionuclide concentrations within the Chernobyl Industrial Zone confirms the presumption that there is a contamination source in the area. The source may be the soil surface of the Chernobyl Industrial Zone that was contaminated in 1986 and then covered with the concrete layer. Also, the groundwater may be contaminated by radionuclides directly from the Unit Shelter.

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2UJDQL]DWLRQ 1XPEHU 2EVHUYDWLRQ 2EVHUYDWLRQ RSHUDWLQJWKH RI:HOOV 6FKHGXOH 6FKHGXOHRI 5DGLRQXFOLGHVWREH &KHPLFDO PRQLWRULQJ $TXLIHU RI *URXQGZDWHU 'HWHUPLQHG &RPSRVLWLRQ 6XEVRLO *URXQGZDW 5DGLRQXFOLGH 5DGLRFKHPLVWU\ 1RWHV HU/HYHO &RPSRVLWLRQ ,QGH[RI 0RQLWRULQJ:HOO Prior to sampling, 200-300 ChNPP, 14 Once per Once per month Volume activity, 137Cs, 90 Sr liters of water is pumped Radiation Safety month Not determined from well by submerged- Shop type pump

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Unit Shelter, 9 Twice per Once per month Volume activity, 137Cs, 90 Sr Once a quarter Prior to sampling, well is Interbrunch month (beyond schedule-238Pu and of year bled by spoon Scientific and 241Am) Technical Center (ISTC) “Shelter” Unit Shelter, 6 Twice per Twice per Volume activity, Once a quarter Prior to sampling, well is ISTC Shelter month month 137Cs, 90 Sr of year bled by spoon (beyond schedule-238Pu and 241Am)  3 Once a Once per month 137Cs, 90 Sr Not determined Prior to sampling, well is quarter of airlifted year

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-46 Pursuant to the distribution of ground water movement (see Figure H23), the western part of the Chernobyl Industrial Zone may be the target of ground water flow contaminated by radionuclides from PVLRO “Stroybaza” (see Figure H1). It should be noted that the epicenter of groundwater contamination by 90Sr is situated to the southeast of the Unit Shelter (see Figure H26b), which suggests that a source of contamination may be the confined aquifers that are located there. Another noticeable contamination source of ground water contamination by 90Sr is located to the north of the Unit Shelter and is associated with the Solid and Liquid Radwaste Repository (see Figure H26b).

Table H7 and H8 show 90Sr concentrations in groundwater at separate areas of the Unit Shelter Industrial Zone, and the Chernobyl NPP Industrial Zone as a whole. The data has been compiled according to the monitoring results performed by the ISTC Shelter in 1996- 1998 [21]. Maximum values of 90Sr concentration were detected at the northern areas of the site, which agrees with the groundwater flow direction. Nevertheless, the 90Sr source has not EHHQGHWHFWHG\HW)RULQVWDQFHWKHZHOO  VHH)LJXUH+ LVORFDWHGQHDUHUWRWKH8QLW Shelter than the well 3G, but the water samples taken out of this well show that the concentration is three times lower than in the well 3G. High concentrations of 90Sr were detected in the groundwater in the area of the head pond and the Liquid and Solid Radwaste Repository. The 90Sr contamination levels are in agreement with the data obtained by the Institute of Geological Sciences in 1995 [18].

In addition to 137Cs and 90Sr contamination in the groundwater at the ChNPP Industrial Zone 238 Pu, 239-240 Pu and 241Am were detected with concentrations up to 3-7 Bq/l. There is also groundwater contamination by toxic metals. The metal concentrations are higher than the respective maximum permissible concentrations as follows: lead concentration is two or three times higher than permitted, the nickel concentration is up to 8 times higher, manganese concentration is up to 13 times higher, and iron concentration is up to 50 –100 times higher [18].

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Area Well April, 1997 July, 1997 September, 1997 April, 1998 July 1998 Liquid and Solid  ± 6 – 67 17 – 245 11 -158 9 - 90 33 –87 Radwaste Repository area, ±  northern part Discharge water reservoirs ± ± 2 6 – 38 3 – 7 17 7 -17 area, northern part 

Unit #3 area, central part ±  55 – 120 92 – 129 84 – 129 100 - 146 92 – 187

Head pond area, ±  22 -264 263 - 329 338 - 365 348 - 608 337 - 720 South part

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-48 +5HYLHZRI6XUYH\5HVXOWVDVWR5DGLRQXFOLGH0LJUDWLRQDW3LORW6LWHRI7UHQFK RI39/52³5\]K\/HV´ +3LORW6LWH'HVFULSWLRQ Radionuclide migration from Trench #22 of the PVLRO “Ryzhy Les” has been studied in the framework of the “Polygon” Programme of the Institute of Geological Sciences, since 1994 at a pilot site. Since 1998, research at this site has been conducted in collaboration with the French Institute of Radiation Safety and Protection and the Research Agricultural Institute (UkrNIISKhR) [2,3,4,5,13].

The pilot site is located at a distance of 2km from the Chernobyl NPP, along the western release trace. Its location is provided in FigureH1. According to 1992 data obtained by the Research and Design Institute of Industrial Technologies of the city of Moscow [5], in the 137 90 239+240 ERG\RIWKHWUHQFK1R WKHUHLV&LRI Cs, 25 Ci of Sr, and 0.32 Ci of Pu. The average specific activity of radionuclides in the disposed materials amounted to: for 137 90 239+240 &V%TNJ  &LNJ IRU 6U%TNJ  &LNJ DQGIRU Pu %TNJ  &LNJ 7KHUHVHDUFKFRQGXFWHGVLQFHGHPRQVWUDWHVWKDWWKHWUHQFK 1R   LV D VLJQLILFDQW VRXUFH RI UDGLRQXFOLGH PLJUDWLRQ VWURQWLXP PDLQO\  LQWR WKH aquifer. At present, the pilot site is equipped with a large number of observation wells, boreholes to study moisture transfer in the aeration area, a weather station, and a laboratory (Figure H27). In order to observe the ground water level, the wells have automatic pressure sensors of TD- Diver type installed [22]. The layout of the multiplayer well with the typical geologic section is presented at Figure H28.

At the pilot site, during the last years, a large number of monitoring observations and special experiments have been conducted (tracing, experimental pumping outs, etc.). Some of the most interesting results are described in below.

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-51 +5DGLRQXFOLGH&RQWDPLQDWLRQLQ*URXQGZDWHU Results of 90Sr concentrations in water samples are provided in Table H9 and Table H10. The two-dimensional model of 90Sr distribution in groundwater that was obtained by the profile of three-levelled wells is provided at Figure H29. Sr-90 contamination can be detected downstream of the trenches, the boundaries of its horizontal distribution are up to 10 m currently (see Figure H30).

The Tables H11 and H12 provide data on 137Cs concentration in the pilot site groundwater. 137Cs concentrations above and below the trench are close to background levels, which are intrinsic to the Exclusion Zone groundwater. In 1997, in addition to 137Cs contamination in water samples, 60Co was detected in small concentrations (Table H12).

7DEOH+6WURQWLXPDFWLYLW\LQREVHUYDWLRQZHOOVLQVWDOOHGDW3LORW6LWHLQ $XJXVW  Well no. Well characteristics Strontium-90, Analytical Bq/l error, % Ground surface Depth interval of elevation, m screen, m 2-98-1 114.1 3.3-3.7 341 22 2-98-2 114.1 4.8-5.3 183 18 2-98-3 114.1 6.8-7.2 44 80 2-98-4 114.1 9.8-10.2 < 20 3-98 114.5 9.8-10.2 38 45 1-99 114.61 4 - 5 3480 13 2-99 114.48 4 - 5 162 37 3-99 114.66 4 - 5 3220 12 4-99 113.37 4 - 5 4750 13 6-99 114.01 4 - 5 505 18 7-99 114.69 4 - 5 1370 14 8-99 114.68 4 - 5 3240 12 9-99 114.67 4 - 5 2200 12 10-99 114.63 4 - 5 2290 12 11-99 114.57 4 - 5 1000 14 12-99 114.44 4 - 5 324 16 13-99 114.35 4 - 5 96 24

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-52 7DEOH$5HJLPHGDWDIRUVWURQWLXPJURXQGZDWHUFRQFHQWUDWLRQVDW3LORW6LWH %TO  Well Well characteristics Date no. Well head Well head Depth 10/95 10/96 05/97 08/97 11/97 04/98 07/98 10/98 08/99 elevation, height, interval of m m screen, m 1-95-1 115.21 0.52 3.5-3.9 6620 12200 14190 13088 11050 7680 9830 13900 7560 1-95-2 - - 4.6-5.0 427 239 196 265 272 286 525 481 1-95-3 - - 6.0-6.4 363 357 313 333 298 333 533 319 2-95-1 115.09 0.55 3.2-3.6 10300 20479 11889 18900 19800 18500 12600 2-95-2 - - 4.4-4.8 1010 724 406 948 1260 600 2-95-3 - - 6.4-6.8 248 17 5 11 < 20 3.7 39 3-95-1 115.06 0.41 3.5-3.9 2070 809 2150 2117 1260 1550 3-95-2 - - 4.45-4.85 3990 4791 2671 4777 6110 6480 5620 6760 3-95-3 - - 6.3-6.7 1550 2444 1322 2817 1810 2350 2380 1500 4-95-1 114.79 0.38 3.5-3.9 1190 2420 3166 1874 4438 4090 5130 3640 3420 4-95-2 - - 4.45-4.85 2970 5648 3159 6789 5880 2440 7160 7760 4-95-3 - - 6.3-6.7 2294 1183 2650 2450 278 3180 2870 5-95-1 114.3 0.49 2.7-3.1 142 265 286 141 225 358 280 278 258 5-95-2 - - 4.2-4.6 14.5 9 11 13 10 10 5-95-3 - - 5.7-6.1 10 1 4 1 <20 1 17 6-95-1 115.23 0.41 3.6-4.0 5310 5290 9763 5899 7994 7000 7690 8550 2120 6-95-2 - - 5.0-5.4 469 405 212 439 431 334 375 346 6-95-3 - - 6.3-6.7 177 45 46 64 129 48 116 92 7_94 114.03 2.8-3.2 136 114 915 208 8_94 114.51 0.71 2.4-2.65 179 122 76 262 Note: Analytical error constitutes: for activity values in the range Q*100-Q*1000 Bq/l – 10-20%; for activity values in the range Q*10-100 Bq/l – 40-80%

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NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-55 7DEOH+&DHVLXP&RQFHQWUDWLRQLQ*URXQGZDWHUQHDU7UHQFK1R-XQH

Well Number Cesium-137 Concentration, Bq/l 1-95-1 0.4 Under trench 5-95-1 0.01 At 20 m distance from trench 8-94 0.06 Upstream from trench

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Well Cesium-137, Bq/l (analytic error %) Cobalt-60, Bq/l (analytic error %) Number 1-95-1 0.9 (27%) 0.53 (18%) 1-95-2 0.05 (83%) 0.055 (50%) 1-95-3 0.09 (80%) 0.07 (48%)

 + 6U%DODQFHLQWKHµ:DVWHGXPSWR$TXLIHU¶6\VWHP The information obtained on the 90Sr spatial distribution near the trench #22-T, allowed an estimation of the radionuclide balance in the system ”waste dump – unsaturated zone - aquifer”. The estimation was based on the study results of ground water contamination by 90Sr, as of October 1995. The estimations were performed using numerical integration methods, using the Surfer program package. The trench profile cross-section of 1m width 3 was estimated. In this case, the soil density was estimated to be 1.65 kg/dm DQG d in the range of 1 to 4 ml/g [6].

The estimation results are provided in Table H13. The estimations show, that by the year 1996, 89 –95% of 90Sr was inside the trench with 4 – 11% of Sr90 having migrated from the trench.

 7DEOH+ 6U%DODQFHLQWKH6\VWHP³:DVWH'XPS$TXLIHU´IRU7UHQFKRIWKH 39/52³5\]K\/HV´DVDW GDWDSURYLGHGE\,QVWLWXWHRI*HRORJLF6FLHQFHV Compartment 90Sr Concentration, Bq (for 1 90Sr, Concentration, % of the total running meter of trench section) in system, as at 1995-96 Trench 1.04 x1010 89-95 Unsaturated 1.7 x108 1.4 - 1.6 zone Aquifer (3.3 - 11.3)x108 3-9.6

+(VWLPDWLRQRI&DHVLXP&RQFHQWUDWLRQLQWKH:DVWH'XPS In 1992, the Research and Design Institute of Industrial Technologies drilled boreholes and carried out gamma-ray logging, in order to estimate radionuclide concentration in the trenches of the PVLRO “Ryzhy Les” [7], including trench #22. In 1999, the UkrNIISKhR re-estimated the 137Cs concentration at trench #22 in more detail. (138 gamma-ray logging

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-56 measurements by the Research and Design Institute of Industrial Technologies versus 2,736 measurements by the UkrNIISKhR). In order to estimate the radionuclide concentration and spatial distribution, a specially-designed field radiometer was used that has a very high HIILFLHQF\RI SDUWLFOHGHWHFWLRQ

The survey results, with 137Cs activity having been re-estimated taking into account radioactive decay since 1992, are shown in Table H14. It should be underlined, that the obtained results are similar, although the number of measurements performed by the UkrNIISKhR is about 20 times higher than the number of measurements performed by the Research and Design Institute of Industrial Technologies.

 7DEOH + &RPSDULVRQ RI 6XUYH\ 5HVXOWV DV WR &V &RQFHQWUDWLRQ LQ 7UHQFK  REWDLQHGE\WKH5HVHDUFKDQG'HVLJQ,QVWLWXWHRI,QGXVWULDO7HFKQRORJLHV DVDW DQGWKH8NU1,,6.K5 DVDW Trench Parameters Research and Design Institute UkrNIISKhR of Industrial Technologies Radioactive masses 1110 1350 volume, m3 Density, t/m3 1,7 1,6 Activity, Bq 1,33 12  

+ (VWLPDWLRQ RI $FWXDO 5DWH RI *URXQGZDWHU )ORZ DQG 6WURQWLXP 0LJUDWLRQ 5DWHLQ$TXLIHU In accordance with the results of the tracer experiment that was carried out by the Institute of Geological Sciences and the French Institute of Radiation Safety and Protection in 1999, the actual rate of groundwater flow in the aquifer was estimated to be 10 m/year [7].

In accordance with the study data of 1999, the migration front of 90Sr in the aquifer was 10 m from the trench. Taking into account waste was dumped in the trench in 1987, the lateral migration rate of 90Sr is about 0.8 m/year, or 7-12% of the ground water flow rate. This corresponds to a Kd distribution factor in the range of 1- 2 ml/g [7].

+&RQFOXVLRQV 1. The groundwater of the Chernobyl NPP Near Zone is contaminated by radionuclides, of which the most mobile is strontium-90. 2. Outside the PVLROs, in the Chernobyl Near Zone, where radionuclide sources are the fuel and condensate particles distributed along the soil surface, the 90Sr specific activity in groundwater typically 0.1 – 1 Bq/l. 137Cs in groundwater was detected at concentrations of n*0.1 Bq/l and lower. 3. At the PVLROs “Ryzhy Les”, “Stantziya Yanov”, “Stroybaza”, “Neftebaza”, the soil surface was disturbed by the decontamination work (soil was either removed, or disposed under ≈50 cm sand layer); and groundwater is significantly contaminated by radionuclides: - Groundwater contamination by radionuclides is localised under trenches (or in waste trenches if they are flooded) and in the vicinity of waste dumps.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-57 - During the study period (1992-1999), the maximum concentration at PVLRO Ryzhy Les of 90Sr was 30,000 Bq/l, of 137Cs was 350 Bq/l, and of plutonium isotopes 238,239,240 was 7,5 Bq/l. - The 90Sr horizontal migration rate from disposal sites (for areas like “Ryzhy Les”) is estimated to be 1 m/year approximately, with 90Sr concentrations in the contaminant plume of typically n*1000 Bq/l (as at 1999). - 137Cs concentration in groundwater is about n*0.1 Bq/l (as at 1999). - Beyond the 90Sr contaminant plume from the waste trenches, the concentration of this radionuclide in groundwater depends on the vertical migration from the contaminated surface and subsurface soil layers with concentrations of about n*10 – n*100 Bq/l (for PVLRO “Ryzhy Les”) (as at 1999). 4. Due to the fact that PZRO “Kompleskny” is flooded by water to a depth of 0.5-0.7m, the radionuclides migrate from the repository into ground water. In this case, the maximum fixed concentrations of 90Sr were up to 310 Bq/l, and of 137Cs were up to 63 Bq/l (as at 1996). 5. For PZROs “Podlesny” and “Buryakovka”, there is no evidence of radionuclide migration from the waste into the groundwater. 6. In the groundwater of the Chernobyl Industrial Zone and Unit Shelter, high concentrations of 90Sr (up to 3,800 Bq/l) and 137Cs (up to 200 Bq/l) have been observed. In addition the groundwater contains plutonium isotopes (3 – 7 Bq/l) (as at 1998). 7. The existing system of hydrogeological monitoring of within the Chernobyl NPP Near Zone that is performed by the enterprise RADEK, within the framework of the Exclusion Zone radiological monitoring programme, has some significant drawbacks (including the poor construction and location of observation wells); and the system needs to be updated.

+5HIHUHQFHV 1. Bugai D A, Dzhepo S P, Skalsky A S (1997). Radiological monitoring of groundwater// Radioecology of water in the area affected by the Chernobyl accident. Volume 1. Monitoring of radioactive contamination of the natuaral waters in the Ukraine (editor Voitzehovich O V). Kiev Chernobylinterinform. In Russian.

2. IGS (1995). Research report ‘Operational and forecasting estimates of the conditions in the Exclusion Zone and development of recommendations for groundwater monitoring. Contract.4/6-95 Kiev, 1995. In Russian.

3. IGS (1996). Research report ‘Operational and forecasting estimates of the conditions in the Exclusion Zone and development of recommendations for groundwater monitoring. Contract.4/6-95 Kiev, 1996. In Russian.

4. IGS (1997). Research report ‘Operational and forecasting estimates of the conditions in the Exclusion Zone and development of recommendations for groundwater monitoring. Contract.4/6-95 Kiev, 1995. In Russian.

5. Ilichev V A, Ahunov V D (1992). Studying of the radwaste dumps, development of technologies and countermeasures to localise and redispose wastes. Radiological and hydrogeological monitoring in the area of dumps and adjacent areas. Report on contract 720-H. NIPIpromtechnology, Moscow-Chernobyl, 1992. In Russian.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-58 6. Dzhepo S P (2000). Study of non-biogenic migration of radionuclides on the program of ‘Hydrogeological test site’, stage 6. Agreement 13/132-155N, IGN. Kiev-1998. In Russian.

7. 1999 Yearly Report for the CEA/IPSN Project “Validating a Pilot Plant in the Chernobyl exclusion area by means of experiments”. Contract No. 990115/SH Ref/ 4060 9B022650. IGS, February 2000. 109 P.

8. UkrNIGMI (1990). Scientific report on the study ‘Investigation of the radionuclide WUDQVSRUW IURP WKH UHVHUYRLUV RI WKH                           

9. V.A.Kashparov, V.P.Protsak, N.Ahamdach, J.M.Peres et al. Dissolution kinetics of particles of irradiated Chernobyl nuclear fuel: influence of pH and oxidation state on release of radionuclides in the contaminated soil of Chernobyl. Jornal of Nuclear Materials 279 (2000) 225 –233

10. Olkhovik Yu.A., Koromyslychenko T.I., Gorgotskaya L.I.et al. Estimation of sorption ability of sandy soils in the Near Zone of Chernobyl nuclear power plant. Reports of the Ukrainian Academy of Sciences, no.7, 1992, pp.167-171 (in Ukrainian).

11. IGS (1993). Report on the study ‘Scientific support to the local and site-specific monitoring of the groundwater and improvement of the methodology aimed at forecasting radionuclide transport based on experimental research in the Exclusion Zone. &RQWUDFW .LHY,Q5XVVLDQ

12. IGS (1998). Report on the study ‘Estimates of the current and future conditions in the Exclusion Zone and development of recommendations on the improvement of the groundwater monitoring. Contract No 4/ 6-95. Kiev, 1998. In Russian.

13. IGS (1994). Report on the study ‘Scientific support to the local and site-specific monitoring of the groundwater and improvement of the methodology aimed at forecasting radionuclide transport based on experimental research in the Exclusion Zone. &RQWUDFW .LHY,Q5XVVLDQ

14. OPOS IGMP (1995). Performance of special experiments concerning the physical and chemical state of radionuclides from PZRO of the Exclusion Zone. MPP Vidrodzheniya. Kiev 1995. In Ukrainian.

15. 15.STC KORO (1998). Report on the study ‘Investigation of PVLRO Peschannoye Plato, preparation of the data for GIS and analysis of PVLRO safety and decision on the operational safety. Phase 5: ‘Radiological characterisation of PVLRO Peschannoye Plato DQG DVVHVVPHQW RI WKH HQYLURQPHQWDO LPSDFW &RQWUDFW   67& .252 1998. In Russian.

16. Sitnikov A B, Tkachenko K D, Golovchenko Yu G (1995). Hydrogeological station ‘Feofaniya’: experience and potential research. Kiev: Hydrogeological journal No1, 1995. In Ukrainian.

NNC Limited C6033/TR/001 Issue 02 (UURU%RRNPDUNQRWGHILQHG Page H-59 17. STC KORO. Report on the study ‘Development of PVLRO conservation projects within the 30-km Exclusion Zone’. Phase 17 ‘Assessment of disposal safety in PVLRO µ.RPSOHNVQ\¶ DQG HYDOXDWLRQ RI WKH HQYLURQPHQWDO LPSDFW  &RQWUDFW   Zheltiye Vody, 1996. In Ukrainian.

18. IGS, 1995. Report on the study ‘Investigation of radionuclide contamination of groundwater at Promploshadka and Unit Shelter. PO ChNPP. Kiev, 1995.-118. In Ukrainian

19. IGS, 1999. Report on the performance of “HYDRO-GEOLOGICAL INVESTIGATIONS. SAMPLING OF GROUNDWATER. DEFINITION OF CHEMICAL COMPOSITION OF GROUNDWATER” SIP, Agreement No 4967-98- S016. IGS, August 13, 1999.

20. Panasyuk N I, 1998. Hydrogeological monitoring in the area of Unit Shelter: Phase 3. ,$7&6KHOWHU 8±&KHUQRE\O,Q8NUDLQLDQ

21. Panasyuk N I, Pavlyuchenko N I, Pravdivy A A et al. (1999) Assessment of radiological contamination of geosphere and calculation of the radwaste quantities, which are localised in the technogenic soils and adjuscent to the Unit Shelter. ISTC Shelter Prepritn 99-2. Chernobyl. 1999. In Ukrainian.

22. Manufacturer: Van Essen Instrumtnts bv. P.O. Box 553, 2600 AN Delft the Netherlands.

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