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;,-.•• ISSN 0250-3552

INIS-mf—8982

NUCOR REVIEW - 1

NUCLEAR DEVELOPMENT CORPORATION OF SOUTH AFRICA (PTY) LTD REPUBLIC OF SOUTH AFRICA

FOREWORD

This review relates to a period of fifteen months, viz. 1 January 1982 to 31 March 1983. The Atomic Energy Board was still in existence from 1 January to 30 June 1982, A report on the activities of the Licensing Branch, which was transferred to the Atomic Energy Corporation of South Africa Limited only on 1 July 1982, is therefore also included in this review.

Because MINTEK at present bears responsibility for uranium extraction, a short report on extrac- tion metallurgy from MINTEK's annual report for 1982 is also included in this review.

On 1 April 1982 the Life Sciences Division of the former AEB was transferred to the University of Pretoria. Because it is now the NUCOR Institute for Life Sciences and is financed by NUCOR, a short report on the activities of the Institute also appears in this review.

J.P. Hugo MANAGING DIRECTOR PELINDABA 83-12-01

NUCOR REVIEW KERNKOR-OORSIG

Pursuant to the reorganisation of state-funded nuclear activities Die herorganisasie van staatsgefinansierde kernbedrywighede in South Africa with effect from July 1982, the Annual Report of in Suid-Afrika met ingang van Julie 1982, het meegebring dat the former Atomic Energy Board was discontinued.' die Jaarverslag van die gewese Raad op Atoomkrag gestaak is. In order to ensure that research and development work of the Om te verseker dat belanghebbende partye, soos in die verlede, former Atomic Energy Board, which is now the responsibility of steeds oor die navorsings- en ontwikkelingswerk van die the Nuclear Development Corporation of SA (Pty) Ltd (NUCOR) voormalige Raad op Atoomkrag, tans die verantwoordelikheid is. as in the past, still made known to interested parties, the van die Kernontwikkelingskorporasie van SA (Edms) Bpk., Chairman of NUCOR, Dr. J.W.L de Villiers, has pleasure in (KERNKOR), ingelig word, het die Voorsitter van KERNKOR. announcing the publication of the first annual NUCOR REVIEW, dr J.W.L de Villiers, die genoeë om aan te kondig dat die eerste covering the fifteen month period from January 1982 to March jaarlikse KERNKOR-OORSIG wat die vyftien maande van 1983. 1 Januarie 1982 tot 31 Maart 1983 dek, verskyn het. A highlight of this period was the announcement by the Minister 'n Hoogtepunt van hierdie tydperk was die aankondiging deur of Mineral and Energy Affairs that a site in the Namaqualand die Minister van Mineraal- en Energiesake dat KERNKOR 'n District was to be developed and operated by NUCOR as the terrein in die Distrik Namakwaland as die nasionale bewaarplek national depository for medium- and low-active nuclear waste. vir medium- en laagaktiewe kernafval sou ontwikkel en bedryf. CONTENTS

FOREWORD 1 HEALTH AND SAFETY 18 Routine Medical Examinations 18 BOARD OF DIRECTORS 4 Personnel Dosimetry 18 Safety and Radiation Protection 18 SUMMARY 5 Training 18 Incident and Accident Statistics 18 NUCLEAR MATERIALS 7 Environmental Radioactivity 19 Uranium Resource Evaluation in South Africa 7 Aerosol Physics 19 Uranium Production 7 Shielding Studies 19 Market Trends 7 Development of Health Physics 19 Uranium Exploration 8 Personnel-Dosimetry Development 19 The Witwatersrand Basin 8 The Karoo Basin 8 FUNDAMENTAL STUDIES 20 Marine deposits 8 NUCLEAR PHYSICS 20 Thorium deposit 8 Accelerator Operation 20 Geological and Allied Research 8 On-Line Computer System 20 Karoo airborne survey 8 Scattering of Fast Neutrons 20 Calibration facilities 8 Neutron-Capture Reactions 20 Geological research 8 Fission Reactions 20 Analytical Methods for Uranium Prospecting 9 Charged-Particle-Induced X-Rays 20 Radioactive Waste Disposal Project 9 Atomic-Physics Studies 20 Radiation Hazards in the SA Mining Industry 9 PLASMA PHYSICS 20 Uranium Extraction Technology 9 Corrosion Register for Construction Materials 10 THEORETICAL PHYSICS 25 Elementary Particles 25 Alternative Fluorination Agents for the Preparation of UFR Theoretical Nuclear Physics, Many-Body Problems and from Uranium Oxide 10 Equipment for Materials Handling 10 Quantum Mechanics 25 Theoretical Plasma Physics 25 Determination of the Best Scrubbing Method for UFfi and HF 10 Numerical Mathematics 25 Uranium Purification on Laboratory Scale using a Con- RADIATION CHEMISTRY AND BIOCHEMISTRY tinuous Mixer Settler 10 OF FOOD COMPONENTS 25 Recovery of Uranium from Carbonate Plant Waste Streams ... 10 Synthetic Fruit Model 25 Fuel Development 11 Radiation Chemistry of Sugars 26 Metallurgical Hot-Cell Complex (HCC) 11 Radiation Biochemistry of Fruits 26 Elprod Project 11 SOLID-STATE PHYSICS 26 Neutron Diffraction 26 NUCLEAR POWER 12 MEDICAL AND BIOLOGICAL 27 Koeberg 12 NUCOR Institute for Life Sciences 27 Duynefontein Environmental Studies 12 Personnel 27 Research Activities 27 RADIOISOTOPES AND RADIATION 13 Nuclear medicine 27 Application and Promotion of Nuclear Techniques 13 Radiobiology 27 Analytical Nuclear Techniques 13 Synthesis of biologically active organic compounds ... 27 Radiation Technology 13 Breast cancer 27 Radiation Treatment of Plant Products 14 Steroid hormone receptors 27 Spices 14 Extended Test Marketing Program 15 TECHNICAL ACTIVITIES 28 Radiation Treatment of Animal Products 15 Research Reactor 28 Process Dosimetry 15 Electronic Engineering 2R Diagnostic Investigations 15 General 28 Radioisotope Production 16 Nuclear instrumentation 28 General 16 Minicomputer and CAMAC systems 28 Radioisotopes for use in industry 16 Microcomputer systems 28 Radiopharmaceuticals 16 Process control and telecontrol systems 29 Manufacture of kits for radioimmunoassay (RIA) 16 General plectronic apparatus 29 Manufactured products 16 Electronic engineering aspects of the tokamak 29 Imports 17 Electronic and process maintenance 29 Exports 17 Manufacture and documentation 29 Waste Treatment and Disposal 29 Prospecting for Source Material and Regulatory Control 36 Decontamination Services 29 Legal Matters 36 Supply Services , 30 Patents 36 Process Development 30 Services 36 Analytical Services , 30 Finance 36 Engineering Services 30 Personnel 36 Computing Sciences 31 Careers exhibitions 37 Universities 37 LIAISON AND INFORMATION 32 Advertisements 37 International Cooperation 32 Retirement 37 Scientific Gatherings 32 Security 37 Visits to Pelindaba 32 Library and Information Services 33 LIST OF PUBLICATIONS 38 I. PELINDABA REPORTS (PEL AND PER LICENSING 34 REPORTS) 38 Koeberg 34 n. PUBLICATIONS 38 Uranium Enrichment Plant (UCOR) 34 m. THESES 38 Information Systems , 34 IV. NUCOR INSTITUTE FOR LIFE SCIENCES : Generic Activities 35 PUBLICATIONS 39 Control of Radionuclides 35 General 35 NUCOR COMMITTEES 40 ADMINISTRATION 36 Meetings • 36 ORGANISATION CHART 23 NUCLEAR DEVELOPMENT CORPORATION OF SOUTH AFRICA (PTY) LTD

BOARD OF DIRECTORS MANAGERS Chemical Operations Mr H.J. van der Westhuizen CHAIRMAN : Dr J.W.L. DE VILLIERS Chemistry Dr W.J. de Wet Electronic Engineering Dr W.P. Gertenbach Finance Mr T.A. Venter MEMBERS Physical Metallurgy Dr CM. van der Walt Dr J.P.HUGO Physics Dr E. van der Spuy Geology Dr P.D. Toens Mr S.J.P. DU PLESSIS Engineering Services Mr M.G. Jordaan f/rom / January /9S,1)) Oirvctiir-Generul: Mineral and Energy Affairs ProfF.G. GELDENHUYS Isotopes and Radiation Dr D. van As Dean of the Faculty of Medicine, University of Pretoria Research Reactor Mr H.W. Niebuhr Dr C.J.F. HUMAN Personnel Mr G. Greybe Chairman : Federale Valksbelegginfia Limited Process Metallurgy Dr R.S. Birkill Dr N, STUTTERHEIM Reactor Development Dr J.F.M. Slabber Chairman : Telephone Manufacturers of SA (Pty) Ltd Computing Sciences Dr A.M. Venter Liaison and Information Mr A.R. Newby-Prasor Elprod Project Mr J.M. Pretoriua EXECUTIVE COMMITTEE

CHAIRMAN : Dr J.W.L. DE VTLLIERS

MEMBERS Dr J.P.HUGO Mr S.J.P. DU PLESSIS OTHER SENIOR OFFICERS Assistant-Manager: Administration(Seruices) Mr A.J. Laubscher Alternates Assistant Manager: Administration (Central Administration) Mr J.J. Hoffman Dr C.J.F. HUMAN Head: Security Maj. O.J. van Graan Dr N. STUTTERHEIM Senior Legal Advisor Adv. H.L. Breedt Resident Medical Officer Dr A. Botha TOP MANAGEMENT Dr J.P. Hugo Managing Director Dr R, van der Walt Gnwfi General Manager Dr N.P. Pienaar (Srnup (h'nerat Manager DrJ.K. Basson Group General Manager Mr C. MöUer Group General Manager: Technical MrJ.G.W. vanZyl Grtmp General Manager: Management Svrvicea SUMMARY Important progress was made with the radiation preservation of avocadoes, bananas and asparagus. In the case of From 1 January to 30 June 1982 the activities of the former asparagus, trials showed that radurisation at doses of 1 to Atomic Energy Board (AEB) continued unabated. Under the 1,5 kGy leads to a dramatic extension of the shelf life of fresh Nuclear Energy Act 1982 (Act 92 of 1982), the Atomic Energy white asparagus and gives it a more acceptable taste. Further Corporation of South Africa Limited (AEC) was established success was achieved with the irradiation of strawberries, 210 with effect from 1 July 1982. On the same date the Nuclear tons being irradiated at Pelindaba during the year. Development Corporation of South Africa (Pty) Ltd (NUCOR) and the Uranium Enrichment Corporation of The new hot cells in the Isotope Production Centre were South Africa (Pty) Ltd (UCOR) were established as full commissioned. On 31 March 1983 there were 821 non- subsidiary companies of the AEC, At the same time the medical and 64 medical users of radioisotopes in South Licensing Branch of the former AEB was transferred as a unit Africa. to the AEC. Attention was again paid to several projects of a fundamental While all other existing scientific and technical activities of nature. These projects relate to nuclear physics, theoretical the former AEB were continued by NUCOR, most of the physics, plasma physics, solid-state physics, radiation AEC's administrative and liaison work was, until the end of ehemistry.and life sciences. the financial year 1982-1983, conducted by the Admini- The demand for the development, construction and strative Departments/Divisions and the Liaison and Infor- maintenance of electronic systems continued unabated. In mation Department of NUCOR, on behalf of the AEC. As the order to support South African industry, a South African AEC began appointing key personnel as of 1 April 1983, these microcomputer standard - the so-called SABUS - was activities have gradually been taken over from NUCOR. adopted. The first meeting of NUCOR's newly appointed Board of The disposal of solid and liquid radioactive waste was again Directors took place at Pelindaba on 2é July 1982. strictly controlled. Approximately 515 564 m" of effluent was Restructuring took place gradually, and by the end of the year released into the Crocodile River during the year. The total under review had largely been completed. actual activity of this effluentwas 115 mCi,i,e, Iessthan3,5 % On 1 April 1982 the Life Sciences Division of the former AEB of the total activity which may be released under the was transferred to the University of Pretoria and is now known authorisation of the Department of Environmental Affairs. as the NUCOR Institute for Life Sciences of the University of Services in the engineering field met diverse requirements, in Pretoria. spite of the problem with staff recruitment and the acquisition The program for the Koeberg nuclear power station of certain materials. (1 844 MW) was disrupted at the end of 1982 by sabotage and NUCOR's computing service was further expanded in respect the completion of both units was consequently delayed. A hot of computer facilities and services to various Departments functional test of the nuclear steam supply for Unit 1 was and Divisions. successfully carried out. Fourteen representatives led by Dr J.W.L. de Villiers, On 2 February 1983 the Minister of Mineral and Energy Executive Chairman of the AEC, attended the IAEA Interna- Affairs announced that the three farms Caring, Geelpan (both tional Conference on Nuclear Power Experience in portions of Vaalputs) and Stofkloof (a portion of Bokputs) in September in Vienna, Austria. The Managing Director, Dr the Namaqualand District were about to be purchased by J.P. Hugo, and the Manager: Liaison and Information visited NUCOR on behali'of the State for development and operation Chile in January at the invitation of the Chilean nuclear as the national depository for medium- and low-active nuclear authorities. Apart from the fact that a number of scientists waste. The area in question comprises approximately 10 000 spent various periods abroad in connection with NUCOR's hectares, and right of ownership of the farms passed to the program and with licensing matters, South Africa's expertise State on 31 March 1983. was once again sought by the IAEA on more than one occasion, by way of invitations to experts to serve on advisory and The operation of the UF,; pilot plant was transferred to UCOR during the year, and the technology, relating to the conven- working groups. A number of highly placed visitors were tional dry process, which goes hand in hand with the again received at Pelindaba; in all, 1140 persons visited Pelindaba during the year. production of UF., and UFr,, was also taken over by UCOR. A highly sophisticated hot-cell complex, capable of handling NUCOR's library, the national centre for literature on nuclear extremely radioactive fuel elements, is at present under science and technology, continued to furnish information in construction. these fields. A total of 2 424 new books and 3 603 volumes of bound periodicals were added to the library stock during the Another project, with the code name Elprod, has also been undertaken to manufacture fuel elements for SAFARI-1. year under review. The total book stock is now 639 799. On 16 October 1982 UCOR appointed a full-time medical The two Administrative Departments and three Admini- officer, which means that a separate medical centre has now strative Divisions of NUCOR rendered a large variety of been established at Valindaba. A new whole-body counter, to services. Including learner technicians and artisans, there be installed at Pelindaba, arrived in South Africa early in were, in all, 2 434 persons in the service of NUCOR on 1983. 31 March 1983. TABLE 1 SOUTH AFRICA'S URANIUM PRODUCTION FOR 1981 AND 1982

DIFFERENCE BETWEEN 1981 PRODUCTION 1982 PRODUCTION PRODUCERS 1981 AND 1982 PRODUCTION tu3o8 % of Total Rank tu3og % of Total Rank tu3og % Blyvooruitzicht 315,502 4,36 8 252,270 3,68 11 - 63,232 - 20,04 Buffelsfontein 631,750 8,73 4 580,500 8,46 5 - 51,250 - 8,11 Chemwes 668,320 9,24 3 606,670 8,84 3 - 61,650 - 9,23 Driefontein Cons. 242,327 3,35 10 224,601 3,27 12 - 17,726 - 7,32 East Rand Gold and Uranium 302,194 4,18 9 264,814 3,86 8 - 37,380 -12,37 Harmony 580,428 8,02 6 591,090 8,61 4 + 10,662 + 1,84 Hartebeestfontein 478,663 6,62 7 429,103 6,25 7 - 49,560 -10,35 Joint Met. Scheme 1 093,416 15,11 2 863,361 12,58 2 - 230,055 - 21,04 Randfontein Estates (Cooke) 591,774 8,18 5 462,837 6,74 6 - 128,937 - 21,79 St Helena (Beisa) 0 253,612 3,70 10 + 253,612 Vaal Reefs 1 693,569 23,41 1 1 721,782 25,09 1 + 28,213 - 1,67 Western Areas 0 170,638 2,49 14 + 170,638 Western Deep Levels 212,484 2,94 12 183,394 2,67 13 - 29,090 - 13,69 West Rand Cons. 190,258 2,63 13 0 — 190,258 Palabora 234,206 3,24 11 257,879 3,76 9 + 23,673 + 10,11

TOTAL TONS U3O8 7 234,891 100 6 862,551 100 - 372,340 - 5,15 TOTAL TONS U 6131,3 5 815,7 - 315,6 - 5,15 NUCLEAR MATERIALS only combined results are published to ensure that the resource figures of the mining and exploration companies Virtually all activities undertaken by the State in South Africa remain confidential. relating to the development of resources of nuclear materials are centred around or coordinated by NUCOR. Five of Uranium Production NUCOR's Departments have, for a number of years, been involved in the Nuclear Raw Materials Program. Approximately 96 % of South Africa's uranium is produced from the quartz-pebble conglomerate ores of the Witwaters- The Geology Department is responsible for establishing the rand Basin, as a by-product or co-product of gold (Table 1). extent and nature of uranium deposits in the Republic of The remainder of South Africa's uranium comes from the South Africa and the compilation of statistics in this connec- Palabora Mine, where it is extracted as a by-product of copper tion. These are submitted to the Minister and to national and and other minerals. international agencies. The work is done in close cooperation with the mining industry and various Government bodies. In 1982 South Africa's production of uranium from the 17 plants in operation amounted to 5 816 t U (6 862 t U3O8). In Work in connection with uranium extraction was continued by comparison with 1981 production, this represents a drop of MINTEK in collaboration with mining groups which are 5,15 %,which, in turn, is0,24 % less than the 1980 production. members of the Nuclear Fuels Corporation of South Africa The condition reflects the depressed state of the world (NUFCOR). uranium market as a result of the delay in implementing The Chemistry Department is entrusted with the respon- nuclear power programs in most countries, In spite of this, sibility of developing new and improved analytical techniques South Africa still continues to produce approximately 14 % of (particularly neutron activation analysis) which can facilitate the uranium of the Western W&rld (Table 2). exploration for uranium and other nuclear raw materials. It is also involved in the basic geochemical characterisation of TABLE 2 mineral deposits. URANIUM PRODUCTION OF THE WESTERN The Isotopes and Radiation Department* carries out radiome- WORLD FOR 1981 trie analyses of uranium ores and assesses radiation hazards COUNTRY in uranium mines and extraction plants. TONU PERCENTAGE 14 800 33 The Process Metallurgy Department is responsible for the USA Canada 7 802 18 development of processes for the conversion of uranium and 6 131 14 other nuclear materials into the chemical compounds and RSA 10 degree of purity required by the nuclear industry. Niger 4 361 South West Africa 3 970 9 Since 1970 the Uranium Enrichment Corporation (UCOR) Europe 2 914 7 has been responsible for all development and production Australia 2 860 6 aspects of uranium enrichment. Gabon 1020 2 1 The design of a suitable metallurgical hot-cell complex was Other 250 completed and construction work is progressing according to TOTAL 44 108 100 plan. The complex is being erected on the Pelindaba main site. At the same time steps have been taken to manufacture fuel The depression in the market has meant that South African elements locally for the SAFARI-1 research reactor. The producers have either curtailed or temporarily suspended project, under the name Elprod, has achieved great success, production, as in the case of West Rand Consolidated and and locally manufactured elements have been used in No. 1 plant of Western Deep Levels. The commissioning of SAFARI-1 since July 1981. new uranium plants at Western Areas and St Helena (Beisa) with their joint share of 6,2 % of the 1982 production has, Uranium Resource Evaluation in South Africa however, compensated to some degree for this loss. The uranium plant at Afrikander Lease was completed in 1982, In terms of the provisions of the Nuclear Energy Act, 1982, but is being maintained. mining and exploration companies are required to furnish NUCOR regularly with details of their exploration and mining Two producers increased their output, viz. Palabora by activities on a strictly confidential basis. This information is 10,1 % and Harmony by 1,8 %. The Joint Metallurgical correlated by NUCOR's Geology Department in order to Scheme, Blyvooruitzicht and Randfontein Estates (Cooke) assess South Africa's uranium resources and production experienced the largest decrease as each showed a production capacity in fluctuating market conditions and on a continu- loss of more than 20 %. ing basis. To be able to carry out these assessments, a number of Market Trends computer packs have been developed which can store and assess the collated data. Although forecasts of resources and Although most of South Africa's production is sold under production capacity are carried out separately for each centre, long-term contracts, it is important to note that the spot price of uranium rose during the last quarter of 1982 and, at the end * Nuclear Physics Department as of I June 1983. of the year, reached $20,25/lb U:!O8, which was $3,25 higher than in August 1982. It would appear that the drop in pressure Thorium deposits of sales, due to large holders of stock, especially American An investigation of thorium resources was completed as part utility companies which finalised their sales by the middle of of NUCOR's mandate to evaluate South Africa's potential in the year, was responsible for this change in price at the end of source material. By far the largest economic resources are the year. associated with the black-sand deposits in the vicinity of The redistribution of the uranium stock is not yet complete, Richards Bay, from which ilmenite, rutile and zircon are and a large quantity of this uranium will come onto the market produced commercially. Monazite production was commenced in the near future. This turnabout in the spot price is thus not in 1982 and small quantities from which thorium is extracted yet conclusive proof that a firm improvement in price has are being exported. begun, seeing that spot transactions account for only 10 - 15 % of the world's total uranium market. However, it does Geological and Allied Research show an interesting trend, the meaning of which will become clear in 1983. Karoo airborne survey The radiometric and magnetic airborne survey of the Karoo In spite of setbacks in the world economy, the Free World's Basin, undertaken jointly with the Geological Survey, was nuclear capacity increased in 1982 by 11 %, while a further 19 completed. The Geological Survey is at present following up new nuclear power stations are expected to be commissioned the anomalies which were found and, to date, thirteen of the in 1983. This trend will probably continue, but at a somewhat seventeen blocks which were covered during the airborne slower rate. survey, have been evaluated. The report is available for scrutiny at the Geological Survey. Uranium Exploration Calibration facilities While not actively engaged in physical exploration, NUCOR maintains close contact with the mining and exploration The use of the gamma-ray calibration facilities at Pelindaba companies and provides technical expertise in a number decreased further because there were only 40 registered of fields. users, as opposed to83 in 1981. Radioelement concentrations based on assayings from five South African laboratories were Uranium exploration activities have markedly decreased. allocated to the four calibrrtion blocks at Lanseria Airport. A Numerous companies have suspended their uranium explora- United Kingdom geophysical contracting firm at present tion and development projects and only the most favourable working in Central Africa was the first to use a foreign prospecting areas are being retained. aeroplane for the calibration of their instruments at this facility. In 1981, 12 companies spent R18.5 million on uranium exploration in the Republic in comparison with R21,5 million Geological research in 1980. It is expected that this slump, in sympathy with the Further underground tests were carried out in the Harmony poor performance of the uranium market, will worsen in 1982. Gold Mine, during which a collimated workfront scanner was The most important uranium exploration work being under- used to determine uranium grades ire situ. The results showed that the uranium grade can be determined with an acceptable taken in South Africa is discussed below. degree of accuracy and that the gold grade, in many cases where the ratio of gold to uranium is known, can also be The Witwatersrand Basin predicted. Research into the sedimentology of the Karoo continues and a number of papers and reports were published. In 1982 prospecting was mainly for gold in the Witwatersrand Several universities undertook research into the earth sciences Basin. Because some of this work was carried out in uranifer- on a contract basis. The most important areas are associated ous ridges, the uranium resources also benefited to some with the uranium potential and geochronology of the Wit- extent. The major target of the exploration was again to watersrand quartz-pebble conglomerate, the granite of the expand the Welkom and Klerksdorp goldfield. southwestern and northwestern Cape, southern Natal and the Bushveld Igneous Complex, as well as with the phosphate The Karoo Basin deposits along the entire Cape southern and western coastal belts. Limited prospecting was carried out in the sandstone deposits in the southern Cape Province and in the eastern Orange Free A symposium for researchers in nuclear technology was held at the end of 1982. A committee was established to meet a State, as well as on the Springbok Flats where uranium occurs long-felt need, viz. to coordinate nuclear geological research in coal. A number of options were exercised over mineral in the country. rights in areas with proven resources. A hydrogeochemical project was initiated in conjunction with Marine deposits several Government Departments. It includes the analysis of uranium in groundwater samples. An extensive hydrogeo- Attention is still being given to the uraniferous phosphorite chemical investigation of the uranium potential of an ancient deposits on the Agulhas Bank, and a program to plot the drainage channel in the northern Cape Province was completed higher-grade areas is in the planning stage. in conjunction with the CSIR. Analytical Methods for Uranium Prospecting A percussion drilling program is also being used to determine the nature and thickness of the surficial material in the area of A foreign consultant, who is also chairman of the NE A/IAEA interest. Research and Development Project on Improvements in the Measurement of Natural Gamma Radiation, visited Pelindaba Radiation Hazards in the SA Mining Industry in 1982 to monitor the calibration blocks at Pelindaba and at Lanseria as part of an international cooperative project. On various occasions advice was given to the Government Mining Engineer and to private organisations. A radiation Radioactive-Waste Disposal Project survey was done on request at a uranium processing plant. The investigation in connection with the choice of a site for the The behaviour of radium and its decay products, which are disposal of radioactive waste continued unabated in the year present in mine tailings, is being studied with a view to under review and the extensive geological and geophysical predicting long-term migration of these products. The gaseous study reached an advanced stage. An official announcement daughter product radon, which escapes continuously from was made on 2 February 1983 that the three farms Garing, mine shafts and tailings dumps, results in continuous radia- Geelpan (both portions of Vaalputs) and Stofkloof (portion of tion exposure. Bokputs), approximately 10 000 ha in size, in the Namaqua- A large number of measurements of the average radon land District, had been purchased as a national depository for concentration around mine dumps were carried out with nuclear waste and would be administered by NUCOR on passive radon monitors. Concentrations of approximately behalf of the State. 0,5 pCi/£ were found, which are higher than the average The depository will be used for at least the rest of this century outdoor concentration of approximately 0,2 as a depository for low- and medium-active waste. The Efforts are being made, in collaboration with the Atmospheric suitability of the site for the disposal of highly active waste Sciences Division of the CSIR, to calculate the distribution of over the very long term will, however, be investigated in radon concentration as a result of effluent from mine dumps due course. and to correlate it with measured values. Factors which A feature of the site is a layer of surface material with a influence the measurement of radon escape from the ground thickness of up to 35 m which covers the granitic and are also being studied so that a reliable measurement of the metasedimentary rocks of the Namaqualand Metamorphic radon escape rate can be found. Complex. This surficial material consists of sand, calcrete and a variety of clays, including kaolin, which are all extremely Uranium Extraction Technology suitable for the retention and immobilisation of radioactive MINTEK has undertaken a comprehensive suite of projects waste. with the object of gaining a thorough understanding of the A geobotanical study was also undertaken to gather informa- leaching sections of uranium plants. Although the available tion on the mutual relationship between ground cover, technical expertise can increase the extraction efficiency to geology and botany. This study will also contribute to the beyond 90 %, the optimum means of achieving this increase eventual recovery of the area. has to be based on demonstrated technical and economic evalu- ations. The overall aim of the work on leaching is thus the The possible migration or distribution of radionuclides in the identification of the techno-economic optimum conditions for vicinity depends to a large extent, on the groundwater maximum uranium extraction at each mine. conditions and the replenishment of groundwater. Extensive geohydrological studies in this regard were carried out, One of these projects concerns the influence of mineralogical including water samples from boreholes and the later assess- factors on the recovery of uranium from Witwatersrand ores. ment of the water quality, age determinations of the ground- Tests that simulate conditions on uraniurn-leaching plants water and the development of sophisticated computer models were conducted on a laboratory scale so that the behaviour of for the simulation of groundwater flow patterns. The age of the gangue and the ore minerals could be established. For the groundwater, as determined using the '4C method, was these experiments, ground rock samples concentrated in one determined as being between 1 000 and 15 000 years, which of the silicates occurring in Witwatersrand ores (sericite, indicates that replenishment of the groundwater by rain is chlorite, pyrophyllite, and chloritoid) and concentrates of minimal. Consequently, it provides an ideal condition for the pure uraninite and uraniferous carbonaceous matter were disposal of low- and medium-active waste. Computer model- reacted with a dilute sulphuric acid solution or a pregnant ling of this groundwater system is at present being carried out. solution from one of the uranium plants. In addition, the dissolution behaviour of uraninite and brannerite-type With a view to facilitating the geological study of the areas minerals (uranous titanates), which vary considerably in which lie under the surficial material, high-precision and composition, were studied under the microscope in polished sensitive airborne magnetic, electromagnetic and infrared sections of material that had been subjected to leaching at surveys were carried out. Seismic geophysical soil surveys room temperature and at 40 °C. were also used initially to plot the area covered by the thickest layer of surficial material, known as the Vaalputs Basin. Other The tests confirmed that chlorite and sericite react with the geophysical soil techniques such as magnetic, electromagnetic leaching solution. Chlorite dissolves congruently at alow rate, and resistivity surveys are also utilised to supplement the data whereas the sericite reaction is" of the ion-exchange type, the of the airborne surveys. potassium ion being replaced by the triatomic hydrogen ion. 10 The uranous titanates are less amenable to leaching, but at that other fluorine compounds could eventually be used for 40 °C the components with low uranium contents dissolve, the preparation of UF6 was also investigated. whereas those approaching the composition of branneriie At the same time a literature survey was made to determine require higher leaching temperatures and concentrations of the advantages and disadvantages of various UO3 preparation reagents. In the dissolution of uranous titanates, titanium methods, because UO.,, in particular, will initially be used as oxide is the remaining undissolved compound. the starting material. MTNTEK developed a procedure for the quantification of the An assembly which can be used to determine, approximately, mineralogical composition of Witwatersrand ores. The pro- the reactivity of XeFa with a variety of U compounds, is now cedure is based on whole-rock chemical analyses supple- being designed. mented by information obtained from X-ray diffraction and Much attention is being given to obtaining physical and microscopic studies. thermodyp.amic data on the various compounds. MINTEK continues to send a representative to the Working Equipment for Materials Handling Group on the Extraction Metallurgy of Uranium, which is under the aegis of the Nuclear Energy Agency and the This project is aimed at developing specialised equipment International Atomic Energy Agency. Members of the Group and procedures for the treatment and handling of materials. are kept informed of technological developments in the At present, a suitable method is being sought for the degassing of UF . A method using fluidisation was developed extraction of uranium. The current activity of the Working 4 and is now being tested on a pilot scale. An on-line method for Group, namely the compilation of a textbook on the tech- the determination of HF was developed with this in mind. nology of uranium extraction, is nearing its end. In addition to sections on uranium-extraction practice in South Africa and The torque requirements for a magnetically coupled mill were South West Africa, MINTEK contributed sections on radio- defined and the design of a pilot unit is being finalised. metric sorting, belt filtration, preconcentration, and mixer- settler design, and a chapter of the economic assessment of Two pilot systems for the concentration of -.iranyl nitrate processes (in conjunction with the Spanish delegate). solution are being tested. Future activities of the Working Group are likely to include Determination of the Best Scrubbing Method the compilation of a textbook on the testing of uranium ores, for UF6 and HF and on activities associated with techno-economics. The aim of this project is to determine the efficiency of various A detailed study is being undertaken of the techno-economics types of equipment for the scrubbing of UF6 and HF. With the of various leaching processes relevant to the gold and uranium use of a pilot venturi scrubber, efficiencies of more than 95 % industries. The cost centres include lixiviants, oxidants, pH over a wide series of UFG loadings have been achieved. Tests control, pulp heating, agitation techniques, and resin-in on a larger scale with packed columns demonstrated an leach. Attention is being paid inter alia to the economics of efficiency of less than 30 %. Work is at present proceeding on bacterial leaching and the recovery of cyanide. a plant-scale venturi scrubber.

Corrosion Register for Construction Materials Tests using chemical traps did not produce satisfactory results. The purpose of this project is to determine which construction materials are resistant to the particular corrosive solution and Uranium Purification on Laboratory Scale gases used in the chemical processing of nuclear materials. using a Continuous Mixer-Settler Contract work is also being undertaken for other Departments This project entails investigating the extraction of uranium, and organisations. Tests are carried out under both irradia- using a solvent, normally in a nitrate medium, both in batches tion and non-irradiation conditions. The corrosion register, in and continuously. The bank mixer-settler for laboratory-scale which the information on the tests as well as the properties of tests is used to produce kilogram quantities of high-grade construction materials are recorded, is cr utinually updated. A uranium compounds which are used as standards. The table giving a summary of this informa'.ion is also available. required number of stages for the purification of a series of feed concentrations with various impurities is also being inves- Alternative Fluorination Agents for the tigated. A membrane extraction process for uranium in the Preparation of UF6 from Uranium Oxide presence of slurry is in an early stage of development. This project is aimed at gathering sufficient data so that an alternative process can be developed by which uranium can be Recovery of Uranium from Carbonate Plant converted to UF6, and the reaction products easily separated. Waste Streams During the period under review, special attention was given to This project is being carried out on behalf of UCOR. erecting and testing an apparatus for manufacturing XeF 2 Its aim is to evaluate alternative methods and to collect under high pressure. The safety report on this was compiled experimental data for the most suitable recovery process so and approved and the necessary preparations are being made that a plant can be designed and built. for the passivation of the apparatus. A thorough literature study was carried out on alternative methods for the prepara- Evaluation of the results of the preliminary tests carried out tion of XeF2 which could be tested later, while the possibility during the year showed that leaching of U from CaCOyCaF., 11 slimes is actually possible. However, it was also obvious that completed, the facility will be equipped to examine and test the analytical methods were not adequate to obtain data on any fuel elements from the Koeberg reactors in which defects which to base predictions. The problems have in the mean- might arise. Post-irradiation testing of samples from time been fully solved. With the results for the leaching of U- NUCOR's materials testing program and surveillance rich slimes already obtained, a minimum leaching and washing samples from the Koeberg reactors will also be carried volume (35 % of the original scrubbing volume) could be out here. determined. Similar tests using slimes low in U are still The HCC is still far from completion, but construction work is proceeding. The mathematical programs for the prediction of processing satisfactorily. alternative combinations are also receiving attention. Elprod Project Fuel Development The Elprod plant manufactured 41 fuel elements (45 % Light-water nuclear power reactors, like those of the Koeberg enriched uranium) and 9 control rods for use in the SAFARI-1 nuclear power station, use uranium dioxide (U02) as fuel. research reactor. Improvements to the casting process, With a view to the possible future manufacture of this fuel in together with additional quality control measures, resulted in South Africa, suitable manufacturing methods which will use a higher alloy-production rate. Jigs and machining techniques local feed material are being investigated and developed. were continuously improved, and techniques were developed for the manufacture cf a special fuel element in which Metallurgical Hot-Cell Complex (HCC) irradiation rigs can be placed. The availability of comprehensive post-irradiation examina- The international RERTR program (Reduced Enrichment tion and testing facilities is a necessary adjunct to South Research and Test Reactor Program), on which NUCOR is Africa's nuclear power program and 'NUCOR's irradiation collaborating, has the target of developing low-enriched testing program. The design of a suitable metallurgical hot- uranium fuels for use in research and test reactors. A decrease cell complex, to be erected atPelindaba, was completed. The in the degree of enrichment to lower than 20 % reduces the erection of the complex was commenced and a considerable risk that the uranium may be applied for non-peaceful uses. A amount of equipment was ordered and received. When development program was initiated. 12 NUCLEAR POWER Koeberg telemetry stations in the southwestern Cape is continuing. A preliminary analysis of these data emphasised the general The program for the Koeberg nuclear power station characteristics and complexities of the atmospheric processes (1 844 MW) was disrupted by sabotage at the end of 1982 and in the vicinity. the completion of both units was therefore delayed. The plan is such that the power station will be completed safely. Windfields at the ten stations were fed into a segmented Physical security measures have been made more stringent at plume model to obtain an indication of plume movement in additional expense and are still being improved. fluctuating local wind conditions. Using data from the Koeberg tower and the telemetry as a basis, distribution predictions A hot functional test of the nuclear steam supply for Unit 1 were made. was carried oat successfully. Unit 2 was prepared for a similar test. Further functional tests of the steam turbines and Basic meteorological data supplied by ESCOM are used to alternators will be carried out as soon as the required steam plan releases so that the regulatory standards for radiation supply from the nuclear plant is available. exposure off the site may be complied with.

Environmental studies at Duynefontein A computer model which will assist in the prediction of plume trajectories was developed and tested, and may be of inestim- The collection of meteorological data by way of the ten able value in an emergency. 13 RADIOISOTOPES AND RADIATION The technique of measuring 2l0Po in biological samples was mastered and will be used in the monitoring of certain mining NUCOR actively encourages the use of radioisotopes and environments to determine the presence of radon daughter radiation in specific applications in industry, medicine, products. agriculture and research. These techniques are promoted directly by the Isotopes and Radiation Department* and the Accidental releases of contaminants into a river meant that Chemistry Department, which collaborate closely with the flow behaviour of the river had to be identified and MINTEK, Industry, Government Departments, Universities quantified. Consequently, the transit times and dilution and other organisations. properties of the river were determined at the request of the Department of Environmental Affairs. This information can Application and Promotion of Nuclear Techniques now be utilised in mathematical models to predict the downstream behaviour of a contaminant so that farmers using Efforts were intensified to inform industry, mining and other river water for irrigation can be warned in time. technical sectors about NUCOR's expertise in the field of nuclear methods and technology. As part of this, an appro- The distribution of casting powder in steel produced by priate brochure was compiled and sent out to numerous means of a continuous casting process, was studied with the organisations. In it, the commercial and professional aspects aid of autoradiography for a steel factory. A method based on of the services which can be rendered by the Nuclear the tracks of alpha particles in cellulose senitrate film was Techniques Industrial Service (NTIS) were strongly developed to make it possible to visually observe the distribu- emphasised. tion of boron in ppm quantities in steel. Various visits to different petrochemical industries were A system by which small differences in the propellent charge especially informative regarding the potential that there of cartridges can be identified within one second was designed appears to be for the application of nuclear technology. A and is being developed for an outside organisation. direct result was that the distribution of cooling water in the oxygen plant of SASOL I is being studied. Analytical Nuclear Techniques Other radiotracer investigations were done for the industrial An X-ray fluorescence method was developed by which one sector on request. can correct for the absorption of X-rays during the analysis of aerosols. It is based on the counting of both sides of aerosol Residence-time measurements were carried out in a rotating filters. Because the method is easy to apply, it is a viable furnace used for the production of sodium polyphosphate. alternative when cellulose filters are used. Samples of the material were irradiated with neutrons for this purpose and used as radiotracers. No noteworthy difference The determination of gold under a variety of circumstances between the residence-time behaviour of material and dust in received considerable attention. the furnace was established and problems with quality control Neutron activation analysis is offered as a service, although could not, therefore, be ascribed to this. the use of the service remains sparse. Endeavours to obtain The flow behaviour of molasses in sugar crystallisers was definite guidelines on specific needs of the geological com- determined with the aid of l:llI. The information obtained munity and the mining sector were unsuccessful. The facilities facilitated the choice of the type of crystalliser which should required to offer a service which will initially entail a small be used in a new plant. volume of work, but which will be multipurpose, were therefore investigated thoroughly. The building up of the The effective volumes of leaching tanks used for the recovery necessary infrastructure for this service is receiving a great of gold were determined on two occasions. Since the effective deal of attention. volume of a tank is a measure of the mixing efficiency, mixing could be optimised by means of these measurements. ml was A comprehensive geochemical investigation of a number of used as tracer. The length determinations of electrodes in uranium deposits in the Karoo was initiated in conjunction electrical arc furnaces were continued. This parameter, as with the Geological Survey. This investigation, in which the well as the consumption rate of the electrodes, is determined chemical factors which could control the occurrence of the 6n with the aid of Co. The information, which can only be mineralisation were sought, wa's completed and a final report obtained in this way during operation, is essential for the is approaching completion. optimisation of operating conditions. The use of mining tailings for the manufacture of bricks may Radiation Technology lead to increased indoor radon concentrations and therefore As stated in the previous report, the package irradiator which increased radiation doses. The natural radioactive content of building materials is being investigated, as well as the escape the former Atomic Energy Board erected for the sterilisation of radon from this re -.terial. This information is necessary for of disposable medical equipment was adapted, after the determining safe standards for the radioactive content of transfer of the service to a private company, for the radurisa- building materials. The use of activated charcoal for the tion of food. measurement of interior radon concentrations is also being investigated and a number of parameters which influence It is the intention, as was the case with radiation sterilisation, these measurements have been identified. to use this irradiator to extend the new technology of food radurisation to industry by means of an irradiation service. *Nuclear Physics Department as of 1 June 1983. Various products are processed on a large scale with a view to 14 investigating these products under commercial conditions, results confirmed the data of previous seasons, where a shelf- and obtaining reliable techno-economic information. life extension of 5 - 6 days for h-radiated fruit was achieved. The successful processing of 150 t of strawberries during the During the summer months from October to December the 1981 season was followed in 1982 by the processing at supply of bananas is frequently irregular, with the result that Pelindaba of a further 210 t which were sold with great prices vary, especially in December. To overcome this success on the Johannesburg fresh-produce market. However, problem, bananas are stored for 10 to 14 days at 13 °C and during the processing it became clear that the package then treated with ethylene. However, it was found that the irradiator, designed for radiation sterilisation, has inherent fruit coloured up during this period and sometimes softened limitations because it requires a dose 10 to 100 times greater within ten days. Several trials were carried out, using a than the dose required for the processing of food products. firmometer to determine the external and internal firmness of Consequently, if the package irradiator has to be operated on the fruit in relation to colour development during ripening. a fully commercial scale (which is necessary for the acquisition The results showed a doubling of the storage time of of accurate techno-economic data) the existing transport irradiated bananas kept at 13 °C in the distributors' ripening system will have to be replaced by a new, faster system which rooms. The untreated fruit was sent to the outlets on the 14th will be able to handle 100 containers per hour instead of 25. At day, while the irradiated fruit was presented for sale only on present, with the help of local expertise, attention is being the 29th day. Two negative effects, which were observed only given to this problem as well as to the possible designing of at the highest irradiation dose, were a slight loss of taste and a irradiators which are specifically suited to food radurisatiun. small increase in phytotoxicity (splitting of the peel).

With the aid of the pool irradiator, other products were The asparagus industry in South Africa is expanding rapidly successfully irradiated and marketed, viz. onions and with increasing potential on the local and foreign markets. asparagus, while large-scale experiments with bananas, papa- Because it is a highly perishable product, heavy losses are yas, mangoes, plums and nectarines were also carried out. suffered each year. At higher temperatures, as in the produc- tion period (September to November) a sudden deterioration A very important outcome of the research and development with a resultant decrease in the quality on fresh-produce carried out at Pelindaba during the past 10 years was the markets and at outlets was observed. Although refrigeration erection of a fully commercial food irradiator by a private reduced the rate of deterioration, it is not adequate for certain company at Tzaneen. Foods which have already been pro- requirements, e.g. transport to distant local markets and cessed and marketed by this firm include mangoes, papayas, consignments abroad. One of the biggest problems is peel bananas and atjar. browning, a physiological senescence problem, which starts immediately after harvesting and is aggravated at higher Radiation Treatment of Plant Products temperatures. As a result the white asparagus loses its Investigations were continued during which heat and refrigera- attractiveness (the green type to a lesser extent) and may be tion treatments were applied together with irradiation to downgraded within a few days. Results of trials demonstrated combat disease. Effective control of several important fungal that radurisation at doses of 1 to 1,5 kGy improved the shelf pathogens and the resultant shelf-life extension was achieved life of packed fresh white asparagus dramatically, especially by applying several combinations of treatments on fruit such when stored at 2 to 6 °C. A second, very important benefit as papayas, strawberries and spanspek (musk-melons). appeared during organoleptic studies where radurised Various small and large-scale trials were carried out in asparagus, which had been stored for several days in normal conjunction with the Department of Agriculture, the Banana trade conditions (approximately 5 °C), had a more Control Board, the University of Pretoria and the S A Coopera- acceptable taste than the untreated samples. tive Citrus Exchange. During marketing investigations of irradiated foods, close collaboration was established and Spices maintained with various marketing agents of fresh produce, two important retail outlets and some of the largest fruit and The investigation of the microbiological quality of spices and vegetable producers which are at present involved in the the application of radiation to improve it was virtually commercial aspects of irradiated products. completed. The microbial quality of most raw, untreated spices is very poor, with total microbe counts of up to 108/g in Culture trials were carried out to confirm fruit-inoculation certain cases. Various radiation doses were investigated. The studies with Rhizopus, Fusarium, and Trichothecium species. microbe loadings of the spices were greatly reduced (99,9 % Combinations of heat and irradiation treatments showed that and more) by low radiation doses. The danger of non-spore- heat followed by irradiation was the most effective sequence, forming organisms which can cause diseases is also eliminated. that extension of the times between treatments reduced the A dose of 2,5 kGy reduced the microbial contamination level in most cases to lower than 10 000/g. A dose of 10 kGy effectiveness of the combination, and that these combination practically caused sterility of the spices in some cases; an treatments were effective for all three pathogens. optimum radiation dose appeared to be approximately 7,5 kGy. Interest in the irradiation of several subtropical fruits, The effect of storage after irradiation on the microbiology of including avocadoes, was renewed in this way. A series of spices is still being investigated. There appears to be a further trials was carried out during the season for which a firmometer reduction in microbe numbers on extended storage after was used to determine texture changes during the ripening of irradiation. The organoleptic properties of irradiated spices irradiated, as compared with unirradiated, avocadoes. The are also still being investigated. 15 Extended Test Marketing Program during cold storage. Boerewors is also a product which spoils extremely quickly, even during cold storage. Low radiation Studies of several products were expanded from laboratory doses were administered and the effect on the shelf life of the trials to large-scale commercial undertakings. In one trial product was investigated from both microbiological and where several tons of bananas were used, irradiated fruit organoleptic points of view. From the start, the control which had been cold-stored kept twice as long as the fi untreated control. In practice, this can assist in eliminating samples (non-radurised) had bacterial counts of > 10 /g. the shortfall, especially during the summer. In a feasibility Radiation reduced the initial contamination level to just higher study with fresh, white asparagus, several consignments were than 104/g, and this value remained more or less constant for irradiated during the peak supply period and stored for longer than seven days. High coliform bacteria counts were several weeks in cold storage before they were marketed found in the control samples, but no coliforms could be during a period when asparagus was not so freely available. isolated from the irradiated samples. The Staphylococcus The possible economic advantages which can be achieved count was reduced from 1,36 x lOVg to as little as 10/g. with radurisation were proved in both of these commercial Pseudomonas is one of the most important spoilage-causing trials. Similar feasibility studies will be carried out in future bacteria of fresh, non-vacuum-packed moat, during cold with other products which have promising economic potential. storage. Radurisation reduced the Pseudomonas numbers, During the first full-scale marketing of radurised papayas in and only after seven days did their numbers again show an South Africa some time ago, serious problems appeared increase. Organoleptically, no meaningful difference between during the first weeks. These problems were traced and, in fresh control samples and radurised boerewors samples was most cases, ironed out at an early stage. More detailed detected. The growth of mould limits the shelf life of biltong, examination revealed that the most important problems were especially if the product is slightly moist when it is packed. related to low-quality picked fruit, and in handling and storage Radurisation markedly improved the microbiological quality through from the producer to the consumer. of the biltong and dried sausage, and organoleptically there The marketing trial with radurised strawberries during was little distinction to be made between radurised and 1981/82 was an unprecedented success. The quantity control samples. The influence of a combination of other marketed could have been even larger, but a severe hail storm physical parameters such as water activity, pH, chemical drastically curtailed production. The trial was repeated preservatives and heat with gamma radiation are also being during the past season when the entire harvest from the same investigated at present. Lactic-acid bacteria are used as a grower was irradiated at Pelindaba. The quantity of irradiated model in this instance. .strawberries was increased by almost 30 % to 210 t. Once again, regular inspections at retail outlets demonstrated that radurised strawberries by far surpassed the untreated Process Dosimetry product. The success with this technique over the past two Because of the increasing importance of dosimetry in the field seasons has led to a high degree of confidence in the radurised of radiation processing, which is expanding all the time, as fruit. An example is that dealers, because of the longer shelf well as because of the wide variety of radiation doses required life of the radurised strawberries, no longer fear that they will for the various applications, it is essential to continuously suffer serious losses with unsold stock over weekends, as was previously the case. Another trend which is developing is that develop new, improved dose meters and to calibrate existing consumers are going back to dealers and specifically asking meters. During the past year various dose meters were for treated strawberries. examined and calibrated against the standard Fricke dose meter. It soon became clear that each one has its limitations in Radiation Treatment of Animal Products respect of the dose range covered; the region of ^ 2-7 kGy in particular, which is especially important for food radurisation, A comprehensive investigation was carried out in collaboration creates great problems because no suitable dose meters are with a private company to determine the effect of radurisation available. Consequently, attention is being given to the of chicken carcases on their microbiological quality and development of meters suitable for this dose region. As the organoleptic properties. Exceptionally favourable results existing methods are also not suitable for intercalibration with were obtained, because it was found that low radiation doses sources outside South Africa, it is essential to develop more extended the shelf life of refrigerated chicken carcases, viz. suitable methods, for example thermoluminescence. This approximately 3-5 days, to more than 30 days in some cases. aspect will again have to receive attention in the near future. No significant organoleptic differences between the radurised and control carcases were detected. The radurised carcases, after treatment, were free of Staphylococcus aureus and Diagnostic Investigations coliform bacteria, and therefore the gamma rays also com- The whole-body counter was used, in collaboration with the pletely eliminated the potential food pathogens such as Radioisotopes Division of the H.F. Verwoerd Hospital, for Salmonella, Campylobacter and Yersinia. The occurrence of diagnostic examinations of patients. The number of examina- these organisms in chicken is being investigated at present. tions was as follows: Other products to which radurisation has been applied Number of patients examined 36 successfully are boerewors, fish, biltong and dried sausage. Number of counts on patients 133 The results are promising, with a drastic extension of shelf life Number of biological samples examined 6 16 99m Radioisotope Production This agent will be made available as a Tc labelling kit for biliary tract examinations, and will therefore be manufactured General in place of parabutyl-IDA. The large-scale production of The various facilities essential for the processing of radio- DISIDA is being investigated. isotopes are in full operation. The operators have adapted 131I meta-iodobenzyl guanidine was developed on special easily to the new hot-cell system and are carrying out their work efficiently and safely. request for the diagnosis of tissues associated with the adrenal glands. Success achieved with patient studies in The delivered products are of a very high quality. At present hospitals may result in the product being produced on a the Isotope Production Centre supplies 17 products on a 09m service basis in future. In a joint project with the CSIR as well routine basis, the most important of which are Tc genera- 123 as the H.A. Grove Animal Centre, I hippuran was success- tors and 192Ir radiography sources. fully developed and transferred to the CSIR cyclotron group The Isotope Production Centre enjoys excellent cooperation for possible production. Since 77Br has much better radiation from a large number of outside organisations, whether in the and dosimetry properties than l3II, r7Br hippuran is at present supply of manufactured products, joint investigations such as being investigated. The project is being carried out in research on new products, or the evaluation of suitable collaboration with the CSIR, the Biophysics Department of products for local use. the University of the Orange Free State, and the Nuclear Medicine Department of the H.F. Verwoerd Hospital. Radioisotopes for use in industry The manufacture of '92Ir radiography sources of 25 Ci and The most important radioisotopes manufactured for medical a2 9Bm l:ll 102 I98 50 Ci each, which was commenced during the year, is progress- purposes are Br, Tc generators, I, Ir and Au, ing very smoothly. The l92Ir industrial radiography market is A gamma camera was purchased and is very useful for the now supplied largely with local products.'However, it is still a development and quality control of radiopharmaceuticals. challenge to satisfy the market, which is very irregular, at all times without losses on the production side. All the various During 1983 radiopharmaceuticals will probably be sub- associated radiographical equipment is now serviced, but it is mitted to the Medicines Control Council for registration. All still felt that rationalisation will produce cost savings. The the necessary care is being taken to ensure that registration one-step service of source disposal, servicing of equipment will proceed smoothly. and provision of a new source is very popular with the users, who realise that it makes a large contribution to productivity and safety. Manufacture of kits for radioimmunoassay (RIA) A selected number of commercial RIA kits for the determina- The other most important radioisotopes which are manufac- tured and supplied for industrial use are '-•'Na,3l Si,4I Ar, B0Co, tion of thyroxine (T4) and tri-iodotyronine uptake (T3U) were *'-Br, S5Kr and '08Au. brought to the attention of a number of users. Although some of these kits were favourably received, there is at present a 8S The success achieved with the use of Kr in smoke detectors changeover to the use of free thyroxine (FT4) RIA, and in mines serves as an incentive for an investigation of the preferably a single-reagent tube method. Up to now, it has not " development of similar smoke detectors for industrial use. been possible to find a manufacturer who can make a suitable The radioisotopes -4Na, :"Si, 82Br and 192Au are used mainly as industrial tracers. single-tube FT4 RIA kit available for redistribution and possible manufacture to NUCOR. During the introduction 60 During the year two consignments of Co radiation sources visits, a general market survey was made on other RIA with a total activity of 78,5 kCi were transported with the aid products; this revealed that there is a great need for a RIA- of a locally manufactured 10 t lead container from Pelindaba reliable thyrotropin (TSH) RIA kit (thyrotropin determina- to the HEPRO irradiator at Tzaneen. After the sources had tion). Nine TSH RIA kits have so far been investigated. One of been placed in the irradiator, a rearrangement of source rods was carried out. the kits could be considered for possible local manufacture if the foreign producer concerned is prepared to cooperate in Radiopharmaceuticals providing the expertise. A steady growth in the use of 99mTc generators is being Although the evaluation of RIA kits is carried out in the maintained, and 30 per week are at present being manufac- SAIMR laboratories in Johannesburg, it will shortly be done tured. Production now takes place during weekdays and at Pelindaba. regular overtime has fallen away. Manufactured products The existing series of labelling kits for the preparation of technetium-99m compounds, viz. DTPA (kidney studies) and The number of neutron irradiations carried out by the Isotope pyrophosphate (bone studies) was successfully expanded Production Centre totalled 670. Altogether 3 101 consign- with the addition of a tin-colloid labelling kit for liver studies. ments of radioisotopes, with a total activity of 6 604 120 mCi, Patient studies, which have been carried out until now with di- were dispatched during the "year. Furthermore, 1351 isopropyl-IDA (DISIDA), are producing promising results. chemical kits for 39mTc labelling were manufactured. 17 Imports Exports r, ...... ,. . t ... . . , Radionuclides with a total activity of 7 775 mCi were Pnvate «gamut»»» imported ndioiiatopeB with a total exported during 19g2 The ^J^ ^ question were activity of 120 331 080 mCi during the period 1 January 1982 beryllium-7, aodium-22, cadmium-109 and cerium-139, all of to 31 March 1983, in comparison with 811 081 083 in 1981. which were produced in the cyclotron of the CSIR. 18 HEALTH AND SAFETY person received more than 30 % of the annual intake limit. The most general radionuclides detected were I3II, cnCo, The health and safety of all members of staff of NUCOR are "Mo, ai)mTc and U. , the concern of the Isotopes and Radiation Department* and the Medical Services Centre. In addition to the internal personnel dosimetry service, an external service was rendered to outside organisations, in Until 15 October 1982 the Medical Services Centre was which 146 persons were involved in respect of thermo- responsible for examinations and assistance to members of staff on both the NUCOR and UCOR sites. With effect from luminescent dose meters, three persons in respect of whole- 16 October 1982, UCOR appointed a full-time medical body counts, and 55 persons in respect of chest counts. officer, which means that a separate medical centre has now been established at Valindaba. Safety and Radiation Protection The Operational Safety Division continued to render assist- Routine Medical Examinations ance to all Departments of NUCOR. The handling of safety In the period 82-01-01 to 83-03-31 the Medical Services aspects was characterised by three general tasks. Assistance Centre rendered the following services: and analyses in the course of routine work were carried out, as in the past, with the greatest responsibility, incidents and For NUCOR, 936 new examinations, 650 repeat examinations and 1 resignation examination were carried out. In addition, accidents received special attention, and safety planning for 1 220 X-ray examinations, 1 332 blood tests and 115 hearing new projects and buildings was given high priority. tests were carried out, while 184 injuries on duty were Operating problems in process buildings continued to lead to attended to, of which 123 were treated in the theatre; these personnel contamination, but in no case did it have serious included the serious injuries of construction workers. The consequences. Planning is geared to preventing such number of persons with various complaints ranging from instances, or at least to limiting their severity. Stricter acute internal medical problems to slight ailments, amounted radiation protection and good operational planning in those to 3 681. operations where the personnel doses were unsatisfactory, In the period 82-01-01 to 82-10-15,1 095 new examinations, resulted in a reduction of doses to more acceptable levels. 369 repeat examinations and 1 resignation examination were Assistance with tasks for which radioactive substances are carried out on UCOR staff. In addition, 1 227 X-ray oxamina- used was, as usual, given at and outside Pelindaba. High- tions, 632 blood tests and 405 hearing tests, were carried out activity sources of kilocurie orders of size were again trans- while 295 injuries on duty were attended to, of which 41 were ported to outside firms. Thanks to the stringent precautions treated in the theatre; these included the serious injuries of taken, the tasks were accomplished safely. construction workers. In the case of UCOR, various com- plaints attended to numbered 1 862. In the planning of new projects and buildings where radio- active atmospheric contamination constitutes a possible Unfortunately, two of the most serious hydrofluoric acid hazard, ventilation and releases to the atmosphere are burns ever occurred recently. This led to more drastic and aspects being given intensive attention. radical treatment of burns. The results exceeded expec- tations, and the two most serious victims suffered no A further development was the compilation of a separate functional defect. annual report by the Operational Safety Division on all aspects of safety on the Pelindaba site. Personnel Dosimetry Training All radiation workers are provided with personal dose meters on a routine basis and records are kept of all doses received. In Formal training of health physics and safety personnel all, beta-gamma film badges were issued to 269 persons, continued at the Pretoria Technikon, in collaboration with neutron film badges to 166 persons and thermoluminescent NUCOR. dose meters to 461 persons. In no case was the annual limit of 50 mSv (5 rem) exceeded, and seven persons received more Four safety orientation courses were presented during the than three-tenths of this value. year and were attended by 299 persons. Urine samples were taken regularly from uranium workers. A Thirty-eight members of staff ppssed first-aid examinations total of 4 010 samples were analysed, of which 610 showed and received their first certificates, while a further 13 more than 10 $g V/iji. The investigation level of 300 §g V/IJJ qualified for second and further certificates. was exceeded in 24 cases. The usual training was provided to fire-fighting and building During the year 321 members of staff of NUCOR were emergency teams, as well as to decontamination workers and examined as part of a routine and special monitoring program with the whole-body counter, and 238 with the chest counter. learner technicians. Thirty persons showed detectable uptakes. Howe"er, no Incident and Accident Statistics * With effect from 1 June 1983, the Physics Department and the Isotopes and Radiation Department were combined into the During 1982,78 accidents were reported, of which 26 caused newly formed Nuclear Physics Department Health and safety work disability. The injury frequency rate was 5,3. Unfor- aspects were entrustedto the newly formed Safety Department tunately, millionaire status could not be repeated this year. ATOMIC ENERGY IMMRIJ : MKMliEKS. TOP MANAfJEMKNT AND SKSIOH OFFICERS S!B MARCH 188Ï . > '" !

Back- Afr-XO T.,,,r,M „r B. »» *r 1« , IHl,nmlrMrJW Hhmi C.MSUir , . ,

MrJ.M Christopher ittM-t. l)r(.J- Unrhcrs NUCLEAR DEVELOPMENT CORPORATION OF S.A. (PTY) LTD

BOARD OF TOP MANAGEMENT DIRECTORS

Dr J.P. Hugo Dr J.W.L. DE VILLIERS Managintf Director Ofiqirmmi

DrN. STUTTEKHEIM Dr J.P. HUGO Dr R. van der Walt Dr N.P. Pienaar Group General Manager Chairman: Tetcphune Manufacturers ofSA. Managing Director Group General Manager (Fly) Ltd

Prof F.G. GELDENHUYS Dr J.K. Basson Dean of (he Faculty of Medicine. Group General Manager University of Pretoria

Dr C.J.F.' HUMAN Mr S.J.P. DU PLESSIS Mr C. Möller Mr J.G.W. van Zyl Chairman Ffdvralc ValksbcleMintis Ltd Oirectar-GenvrakMincralandEitergyAffairs Group General Manager • Technical GroupGeneral Manager: Management Services ORGANISATION CHART

PARLIAMENT and MINISTER OF MINERAL AND ENERGY AFFAIRS

ATOMIC ENERGY CORPORATION OF S.A. LIMITED (UCOR)

| NUCLEAR DEVELOPMENT CORPORATION OF S.A.(PTY) LTD CHAIRMAN BOARD OF DIRECTORS and EXECUTIVE COMMITTEE

LIAISON WITH X COMMITTEES Uranium' Industry MANAGING DIRECTOR Patents (AEC) ESCOM Nuclear Technology Universities and Radiation Scientific organisations I Life Sciences MANAGEMENT COMMITTEE 1 TOP MANAGEMENT X SCIENTIFIC DEPARTMENTS LIAISON AND MANAGEMENT TECHNICAL AND OTHER SERVICES Chemistry INFORMATION SERVICES Chemical Operations Computing Sciences (Services) Computing Sciences (Development) Public Relations Departments: Electronic Engineering (Development) Electronic Engineering (Services) Language Services Administration Engineering Services Geology Reprographic Services Finance Nuclear Engineering Medical Services Personnel Research Reactor Nuclear Physics Library Services Physical Metallurgy Divisions: Safety Process Metallurgy Legal Matters Reactor Development Security si/i1 fViwIfiuts) in Nnmtiqunland trhcrv rndinactive traite will br atnred in futurv Drilling is bnnt> rarnrd uut w *tudv the giiiingical charactvrit,tirs of tbv s 23 Environmental Radioactivity adapted to determine the precipitation positions of the particles should a particle already have fallen onto the surface Air-particulate, deposition and moisture samples are col- of the filter. Interception efficiencies were also determined lected continuously in the Pretoria and Cape Town areas for from the stream function field obtained by means of the model. the purpose of detecting increases in radioactivity over South Africa from sources such as nuclear-weapons testing by other A model which simulates the flow of an ideal liquid in a countries. Monthly samples are analysed for gamma-emitting bronchus was developed and successfully applied. 90 nuclides, tritium and Sr. Samples are also collected at Various computer codes which model the release of aerosol Pretoria for the Environmental Measurements Laboratory of after a reactor accident were compared qualitatively. the US Department of Energy in New York, and for the Environmental Sciences and Medical Division of the United Shielding Studies Kingdom Atomic Energy Authority (UKAEA) at Harwell in England. Low levels of 90Sr and ':17Cs similar to those of the Shielding work during the past year was restricted to the stratospheric inventory of earlier tests are still observed. calculation of shields and dose rates for practical assemblies and facilities and was done at the request of individuals and Preliminary trials were carried out with adhesive collectors to organisations. A large amount of correspondence took place monitor the atmosphere for airborne uranium compounds. with the developers of the MORSE Monte Carlo program who The results indicate that the collectors may be suitable for are still experiencing problems with some of its options. These qualitatively monitoring the atmospheric environment for problems have not yet been solved. uranium releases. Special attention was given to the adsorption-desorption Development of Health Physics mechanism of ~r'Ra and to the role of clay minerals present in Airborne releases of radioactivity from buildings are still tailings dams. The influence of Thiobacillus ferro-oxidans on being monitored regularly so that proper control over releases the availability of 22BRa for leaching out of this waste material can be exercised, Where necessary the radionuclides are is also being investigated. identified. Profiles of radium concentrations carried out on the original The remote-controlled observation vehicle was completed soil below these forty-year-old tailings dams showed no 22fiRa but is not serviceable at present because of various technical contamination of this soil. problems. A survey is being carried out with a view to evaluating radium 4 $ a sequel to the laboratory model HF monitor, a prototype is concentrations in surface waters and in various biological currently being built. systems in the vicinity of mining areas. Personnel-Dosimetry Development Aerosol Physics A new personal TL dose meter was developed which uses LiF Particulate-size determinations with the aid of Nuclepore flakes and can differentiate between the dose contributions of filters were continued in various uranium plants. The analysis gamma rays and high-energy beta rays (> 1 MeV). These of all samples taken has not yet been completed. The dose meters are now manufactured locally and it is expected particulate size of a UO F.> aerosol arising from a UF release 2 6 that they will be issued from the end of March 1983. was determined and an AMAD of 1 [xm was found. Research work is also being done to determine the effect of A complete testing technique to determine the efficiency of high environmental temperatures on the use of TL materials off-gas scrubbers for a UO.,F aerosol, was developed and 2 like LiF and CaF which are used for environmental monitoring. tested on two different types of scrubber. The importance and 2 value of these tests was demonstrated. This kind of scrubber In the field of internal dosimetry, extensive research on in vivo was also tested for HF. uranium monitoring was done and a new design of a prototype is at present being finalised. A new chest counter receiving Various testing techniques were investigated to determine the high priority is being designed from this prototype for filtration efficiency of large ventilation systems. The most important test aerosols and measuring techniques considered manufacture. were a chromium oxide aerosol with a condensation nucleus The new whole-body counter which will be installed at counter or by means of neutron activation, a copper sulphate Pelindaba, recently arrived in the country and should be aerosol with a condensation nucleus counter, or by means of installed soon. neutron activation and a silicon liquid aerosol with an optical particle counter, or by means of neutron activation. Research work is also being done with the aid of a phantom to determine how well organs can be localised with activity by The loading properties of large-pore Nuclepore filters was means of a scanning-type, single-crystal, whole-body counter. further experimentally investigated with a variety of aerosols. On the more basic terrain of dosimetry, great success has been A theoretical model which describes the transport of particles achieved with the calibration and design of neutron rem through a large-pore Nuclepore filter was implemented. monitors by using computer models. It has been demon- Efficiencies of these filters for various particle sizes were strated that these models are suitable for design and calibra- investigated. With a view to describing the loading tion work and some improvements to existing rem monitors mechanisms of the above filter with a model, the model was are being investigated. 24 FUNDAMENTAL STUDIES Charged-Particle-Induced X-Rays A number of NUCOR scientists are engaged in research The application of the technique which uses proton-induced projects of a fundamental nature, some of which are briefly X-rays to measure air-particulate samples, remains the main described below. application^ oTthis sensitive multi-element analysis method for small samples. The escape properties of intrinsic germa- NUCLEABP^HYSICS nium X-ray detectors was the subject of ah in-dëpth investiga- tion in connection with their quantitative role in analysis and Accelerator Operation their application in the measurement öf inherent physical The accelerator was used almost exclusively during the past parameters of detectors. The measurement of the Fano factor year to produce direct-current beams of heavy ions for use in for germanium at extremely low energies was particularly the 1,1 m diameter scattering chamber. To prevent charge important. This work has been accepted for publication. The exchange during acceleration, it was necessary to improve the study of the effect of scattered protons on X-ray detectors has vacuum in the portion of the accelerator tube near the ion been completed and accepted for publication. source by removing parts of the pulser and buncher which obstructed the gas flow. A gas stripper was manufactured and Atomic-Physics Studies installed in order to obtain higher charge states which are The 1,1m scattering chamber was used for a series of studies necessary to bend the heavy-ion beam through the 90 ° of the charge-exchange mechanism of the interaction between magnet. Beams of N, Ar and O were accelerated. The heavy ions and noble gases. performance of the accelerator during the year was satisfactory. The apparatus was developed in such a way that it allows for On-Line Computer System the specific selection of any incoming charge state as well as for the analysis of the total range of outgoing charge states. The computer was linked to the experimental data-acquisi- Single-collision interactions in gases were, in particular, tion system using a CAMAC interface. The system and the studied as a function of the depth of penetration of nitrogen necessary programs were developed for the collection of and argon ions into the inner-atomic shells of N, Ne, Ar, Kr single or double-parameter spectra. The addition of a graphic and Xe. Results demonstrated that in the region from 1 to display terminal now makes it possible to generate two- 3 MeV, the interaction of Ar indicates a simple compound parameter spectra in rotatable isometric form. type of interaction, while the nitrogen interactions are more complex. The results of the measurements for N obtained Scattering of Fast Neutrons have been accepted for publication, while those for Ar are Anomalies in the level scheme of 100Ag were resolved by the being prepared for publication. ln9B successful completion of the study of the beta decay of Pd. Nitrogen ions were used to investigate the anomalous yield of The work was accepted for publication. ions backscattered precisely through exactly 180 °. A stronger A series of (n,n y) measurements were carried out on Zr, Fe effect was observed than initially predicted. Analysis of the and Li in order to resolve discrepancies between cross charge-state dependence of the anomalous yield and a study sections obtained from (n, n y) measurements when Zr or Fe of the associated energy spectra indicated that the idea of were used as standards. small-angle correlated scattering as being somewhat analogous to microchanneling, and path reversibility may be largely Neutron Capture Reactions responsible for the effect. This work was submitted for publication. During the studies, an interestinginvestigation of 13S The study of the single-neutron binding energies of Pt and the pulse-height defect for heavy ions in silicon detectors was 196 Pt were completed and described in a PEL report. A undertaken, including in particular the effect of channeling in sophisticated computer program, GRAP, was developed inter the dead layer for specific orientations of the position- alia to process the approximately 800 transitions in the 74Ge sensitive detector. level scheme. The results of the 27A1 (n,y) and 3r'Cl(n,Y) measurements done in collaboration with the Munich- PLASMA PHYSICS Cologne-Grenoble Group at ILL Grenoble, were processed An endeavour was made to create conditions for repetitive and published. The study of the /J-decay half-lives of 2:laTh, tokamak discharges with high plasma purity and high particle formed by thermal neutron capture in 2il2Th, was completed. density. These plasmas have better characteristics than before and are, in general, easier to diagnose. Notwithstand- Fission Reactions ing intensive efforts to prepare the vacuum chamber properly, discharges mostly manifested a component of non-thermal The neutron-neutron angular correlation of fission neutrons electrons. The reason for this was traced back to vacuum leaks from thermal-neutron-induced fission of 235U, was studied by in the main seal between the two halves of the vacuum using time-of-flight methods. A foil of 235U was purchased so chamber, a: i well as to metal seals in other places which did not that angular correlations between fission products and 2B2 have precisely the correct specifications. It required a time- neutrons can now be measured. Studies of Cf will com- consuming partial dismantling of the machine to solve the first mence when the foil, which has been on order for a long problem. The second one was solved by a local firm which time, arrives. after several attempts, manufactured seals with improved 25 specifications. These changes eventually meant an improve- Theoretical Plasma Physics ment of orders of magnitude of the basic vacuum. According to the Lawson criterion, the product of particle A great expert in the field of tokamaks paid a short visit to the density and confinement time in a deuterium-tritium plasma laboratory in April, He was able to demonstrate how to must exceed the minimum value 1014 s/cm3 to make possible produce stable discharges at high densities without observ- the gain of energy from nuclear fusion reactions. The influence able non-thermal components by careful programming of of electromagnetic radiation losses (mainly line radiation) on variables. He recommended a number of improvements, inter the density limit above which the plasma becomes unstable, alia how to prepare the walls of the vacuum chamber by means was investigated, and results are leading to a more optimistic of titanium sublimation. This is to ensure that the experimen- view of the situation. tal starting conditions are always the same and that plasma contamination by oxygen and carbon dioxide is largely Another aspect of plasma physics which is being investigated suppressed. This meant that certain equipment had to be is the problem of making a current flow in the tokamak by acquired subsequently and that protective shutters had to be means of electromagnetic waves. It appears that the resultant attached to the insides of observation windows. There are stochastic movement of the electrons may well cause the strong indications that it will be possible to achieve high- possibility of a plateau in the distribution function. It will then purity plasmas with densities of ^ 1014 cm"3. However, these yield a current for plasma confinement, similar to the current densities require more ohmic power late in the discharge. which causes the external transformer in the tokamak, but Further problems were experienced with the switching gear at with the advantage that it is a constant current, in contrast higher current values, which meant that these conditions with the above current. could not yet be attained regularly. Switching gear to yield The finite orbital ray effects on electromagnetic wave propaga- more power is expected shortly. tion and on magnetohydrodynamic stability was further in- New diagnostic equipment which was commissioned contri- vestigated. In the case of ballooning instabilities, the finite buted to a higher level of experimental ^ctivity. Optical orbital-radius effects improve the stability. In the case of spectroscopy in the visible field, for example, now produces microinstabilities, the theory also gives Landau damping for important data on plasma purity and will, hopefully, be able to short wave lengths and large orbital radii, even in the case of produce information on temperature and density. Plasma finite but large orbital rays, in contrast with Bernstein's peripheral conditions can also now be observed by means of a results. Apart from the plasma studies directly related to the Langmuir probe and correlation made with electromagnetic tokamak, plasma studies were also done on general plasma signals which are sensitive to particular internal instabilities. problems, especially spatial plasmas as a field of application. Development work is progressing well on several other The main aspects which received attention were the collision- systems; for example, a diode array for observing soft X-rays, free shock wave in the earth's magnetic field and the shock a bolometer array for total radiation loss measurements, acceleration of cosmic rays. thermocouple array around a segmented limiter to measure energy loss to it, and also an ion temperature analyser are Numerical Mathematics being developed. A start has already been made in observing The object of the numerical calculations during the past year plasma behaviour and instabilities as a function of plasma was the ballooning modes, as well as the rewriting of the current and density with a view to possibly determining the program for the calculation of equilibrium in the tokamak, boundaries of this parameter space. RADIATION CHEMISTRY AND BIO- THEORETICAL PHYSICS CHEMISTRY OF FOOD COMPONENTS Elementary Particles Synthetic Fruit Model The derivation of the weak-decay interaction from the strong Radiation chemical principles are applied in this project in an interaction was further investigated and the comparison of the unification in question of particle interactions with those in attempt to determine only those components in food which other models was considered in greater detail. The origin of will probably undergo chemical changes during radiation the symmetry of the strong interaction under discrete trans- ionisation. formations was the subject of a new comprehensive discus- sion. The developments were also discussed during an Either competitive or solid-state treatment of the com- overseas visit. ponents of the fruit model can be used for the prediction of the degradation profile which, subj ect to the following limitations, Theoretical Nuclear Physics, Many-Body can be expected during gamma irradiation: Problems and Quantum Mechanics - the main component of the fruit is water; During a visit to the Stony Brook University, USA, the - almost all the interactions take place by way of water development of the phenomenological interacting boson radicals; model was continued and applied to microscopic calculations. - only relatively small concentrations of fruit components are The foundations of quantum mechanics, in particular the present and almost no interaction takes place with other measuring processes for angles and angular momentum, were components or directly with the gamma rays; investigated. New results on localising ability were obtained, - a single correction term in the model can represent all as well as a new uncertainty relation. deviations from the above limitations. 26 The yield of calculated radiolysis products compares satis- (a) Inhibitory effect of radiation on the ripening processes of factorily with established yields both in the model and in the fruits actual fruit systems of the mango. The radiolysis products The aspects of this work which are being undertaken are most present in the yield, are the results of the effect of chiefly concentrated on the in vivo and in vitro effect of gamma radiation on the sugars and oxygen which lead to the radiation on the malate enzyme of the ripening mango fruit. production of carbonyl compounds and hydrogen peroxide. This enzyme plays a very important role in the biochemistry Protein, malic acid, the phenols and niacine also degrade in and physiology of fruit ripening. Other parameters of physio- the mango, but to a far smaller extent. Very low yields of logical importance which were investigated together with the radiolysis products due to the degradation of ascorbic, malate enzyme were the total titrable acid content of the fruit, glycolic and tartaric acid, glycine, arginine and RNA can be the fruit pH, respiration as CO release and loss of mass. expected. The conclusion is that the higher sugar content of 2 the mango is responsible for the protection of the other (b) Browning of some fruit varieties after radiation treatment components of the mango. The work was directed towards investigating the effect of In order to extrapolate the chemiclearance concept of whole- gamma radiation and combination treatments on the enzyme someness evaluation to other irradiated fruits, it is important phenyl alanine ammonia liase and polyphenol oxidase, Radia- to determine whether the protective effect of the carbo- tion causes an increase in the activities of the two enzymes; hydrates is slso as prominent in fruit with other component this, again, gives rise to accumulation of phenolic components concentrations. Strawberries, lemons and tomatoes were in the fruit which lead directly or indirectly to fruit browning. selected because they contain a smaller series of sugars than (c) Radiation-induced biosynthesis of phytoalexine in certain the mango. Calculations of the component degradation of these fruits yield very similar degradation spectra which fruits support the basic acceptance of the chemiclearance approach. Preliminary studies indicated that radiation treatment leads Small differences were noticed in the protein degradation and to the biosynthesis of phytoalexine - natural metabolites with they are directly related to the sugar concentration; it actually anti-fungus/bacterial activities. If this applies for all fruit appears as if the only actual difference in the degradation tissue, it has an important implication for the radiation spectrum of fruits with different sugar concentrations lies in preservation of fruits in the sense that radiation treatment the protein fraction. Small variations in organic acids, makes the fruit itself susceptible to spoilage by organisms. ascorbic acid, niacine, the phenols and amino acids are insignificant and are directly related to the variation in the (d) Enzyme phenyl alanine ammonia lyase of irradiated fruit initial concentrations of these components in the three types tissue of fruit. These theoretical calculations are supported by The project is of fundamental importance due to the experimental data. radiation-induced increase in activity of the enzyme which plays an important role in the secondary metabolic paths of The overall conclusion is that the essential agreement phenyl propanoid biosynthesis. The involvement of the between fruits in relation to their radiation chemical enzyme of subprojects (b) and (c) also calls for a more behaviour was proved und that, in addition, it is possible to penetrating study of the induction of the enzyme. extrapolate wholesomeness data from one fruit to another. This project is at present almost complete and the results will SOLID-STATE PHYSICS be summarised in a Ph.D. thesis. Neutron Diffraction Radiation Chemistry of Sugars An experimental investigation of the nature of the magnetic phase transition for the tetragonal antiferromagnet Fe As is The synthesis and characterisation of compounds which may 2 be able to explain the mutagenicity effects in one-component being undertaken. sugar solutions is now complete. Mutagenicity testing of these The purpose of this is' to achieve finality on whether the compounds, the modelling as well as actual examination of the transition is uninterrupted or not (since there is a difference of fruit by means of the Ames test was also completed. In this opinion about this in the literature), and, if it appears to be a way it has been possible to round off this important project second-order transition, to determine the critical exponent which forms part of the radiation-chemistry program of the which is associated with the sublattice magnetisation. The International Food Irradiation Project. The results have temperature dependency of the magnetic reflections (OO'V2), been collated in a publication accepted by the Journal for 5 7 3 (00 /2), (00 /2), (10V2) and (H /2) was determined. Agricultural and Food Chemistry. The results gave no indication of a first-order transition. Radiation Biochemistry of Fruits Furthermore, all the reflections, with the exception of the (10'/2) reflection, demonstrated excellent repeatability in According to a research agreement between NUCOR and the experimental runs from room temperature to above the Rand Afrikaans University, the radiation biochemistry project magnetic transition at TN= 350 K and back to room tempera- was transferred to the Biochemistry Department of that ture. However, the (10'/2) reflection showed deviations University during 1982. During the year, several projects, between the observed curves during heating to above TN and based on previous research carried out at Pelindaba, were the measurements after cooling. This effect is probably due to formulated and at present the project consists of the following non-repeatability by which differently orientated antiferro- subprojects. magnetic regions form when cooling takes place through TN. 27 Preliminary analysis of the spontaneous sublattice magnetis- Overseas interest in the work led to liaison and cooperation ation as measured for the (00 ê/2) reflections, indicates a with various organisations. critical exponent p^ 0,31 if values of magnetisation over the entire temperature region between room temperature and TN Radiobiology are included. A correction for the effect of critical scattering The increasing therapeutic, clinical and industrial use of near TN has, however, to be made and for this the observed scattering above TN must be fitted to the scale relation radioactive nuclides necessitates the study of the effect of 8 ICM(T-TN)/TN]- . irradiation on biological systems. The genetic material (DNA) However, the experimental results could not be associated is generally regarded as the most critical cellular target. The with those in the above connection. The investigation is being determination of DNA radiation damage is therefore extended to measurements on a second crystal to further important for the development of biochemical monitoring investigate the deviation. It also appeared that the back- systems which could be valuable in cases such as radiation ground scattering of the existing furnace is too high for the accidents, radiation therapy, the identification of radio- measurements which are carried out above TN, A new furnace now under construction was designed to overcome this sensitive individuals and the effect of low-dose exposure on problem. persons who continuously work in an environment where irradiation is always a hazard. During this period a changeover was made to the HP computer system for the operation of the KO diffractometer. Rate-zonal centrifugation in neutral linear sucrose gradients The project to grow single crystals from uranium compounds is one of the most sensitive methods for the detection of DNA was continued. The size of the crystals requires long heating damage, and because of the radiosensitivity and availability of 'times, even up to four weeks, during which the apparatus has peripheral lymphocytes, this method was developed in a to be operated uninterruptedly. Consequently, an endeavour unique way so that the DNA damage in human B-lymphocytes was made to solve problems with the long-term operation of the induction furnace, such as insufficient provision for the could be determined to dose levels even as low as 0,05 Gy removal of waste water, encrustation due to impurities in the (which means approximately one DNA single-strand break cooling system, and inadequate ability of the vacuum > °vstem per chromosome). The method comprises, inter alia, centri- to handle evaporation of S, Se or Te at high temperatures. fugation in a vertical rotor (Beekman Vti-50) in 15-30 % linear sucrose gradients which contain inter alia the fluorescent MEDICAL AND BIOLOGICAL DNA bonding dye, Hoechst 33258, and was further adapted NUCOR Institute for Life Sciences for the study of DNA repair kinetics, the determination of DNA radiation damage of lymphocyte subpopulations, The Life Sciences Division of the former AEB was transferred, on 1 April 1982, to the University of Pretoria and is now human fibroblasts and rat hepathocytes, as well as the study known as the NUCOR Institute for Life Sciences of the of the effect of neutron irradiation on human lymphocyte University of Pretoria. DNA.

Personnel Synthesis of biologically active organic compounds The staff of the Institute consists of 18 persons. A continuous program for the design and synthesis of radiopharmaceutical compounds with possible organ and/or Research activities pathological specificity was continued. Three areas were concentrated on: The research activities and cooperation with local and foreign medical scientists expanded greatly. All research projects of - Synthesis of chelating cyclic peptides. the Institute are continuous in nature. Some aspects of - Synthesis of potential agents for the detection of ischaemic existing projects were completed. The following projects all heart lesions. progressed very well: - Radioisotope-labelled polymers for gastric studies.

Nuclear medicine Breast cancer The application of nuclear techniques in diagnostic medicine More than 2 000 determinations of carcino-embrionic antigen with the aid of -the gamma camera of the Institute was continued at the H.A. Grove Experimental Animal Centre. of patients from the Chemotherapy Department of the Projects included the following: H.F. Verwoerd Hospital were carried out and are also of great value for drawing up treatment protocols. In addition a large - Pacemaker studies of baboon hearts. - Effects of fitness on blood volumes and left ventricle number of hormone receptor determinations were carried out rejection fractions of Beagle dogs. on tissue specimens. - Radionuclide scannings to evaluate the healing of bone fractures. This work was done in collaboration with the Eastern - Evaluation of fibrin gum in the mastoid-bone healing Oncology Research Group in the USA, and with the process. Chemotherapy and Pathology Departments of the H.F. Ver- - Kidney studies - influence of medicines on kidney function. woerd Hospital in Pretoria. - Use of blood platelets labelled with indium-HI for the diagnosis of deep venous thrombosis. - Gastric transit times and colon delineation with radio- Steroid hormone receptors nuclide-labelled polymer resins. This work led to a number of new studies carried out in collaboration with various Detection methods for steroid receptors in normal as well as Departments of the Faculty of Medicine. cancer tissue were developed. Attempts with radionuclide- - Study of baboons contaminated with the chikungunya labelled tumour detectors aimed.at these receptors also virus. progressed well. 28 TECHNICAL ACTIVITIES The activities of the Department comprise the following: Research Reactor Design and development of electronic apparatus and systems in the above categories. The SAFARI-! reactor, which is operated by the Research Reactor Department, functioned satisfactorily throughout Manufacture of developed items and systems. This involves the year. The reactor was generally operated in cycles of seven the manufacture of printed circuits, electronic assembly, weeks, consisting of operation for 24 hours per day, five days instrument wiring, system wiring and mechanical manufac- per week, over a period of six weeks, followed by shutdown of turing work relating to the above. one week for maintenance. A consultancy service rendered by professional engineers in The core configuration, consisting of 28 fuel elements and six respect of the electronic engineering aspects of NUCOR's control rods, remained unchanged. Seven fuel elements and projects. two control rods were manufactured locally and loaded into All documentation aspects associated with the above. the core. The core was reloaded eleven times during the year. The maintenance of electronic apparatus and systems on The fuel inventory, at the end of March 1983, consisted of the site. 5,1 kg uranium-235, in the reactor core, 0,37 kg in new The provision of an electronic- and process-instrumentation elements in the vault and 3,1 kg in depleted and partially calibration service. depleted elements in the storage pool. Altogether 42 spent The maintenance of process instrumentation in plants on the fuel elements were sent to the USA for reprocessing. site, as well as the maintenance of site services such as public- The most important operating data for the period 1 January address systems, radio communication systems and security 1982 to 31 March 1983 are as follows: systems. Average power, MW 5 Nuclear instrumentation Accumulated energy, MW.d 988,9 Number of capsules irradiated 7 980 The nuclear-instrumentation development program pro- Number of unscheduled shutdowns 10 gressed well. An automatic neutron-flux control system for Number of major experiments operated 3 SAFARI-1, in which locally developed nuclear instrumen- tation was used, was successfully commissioned. Further In-core thermal-neutron-flux distribution measurements development work in respect of a measuring channel in which were done on a regular basis, the results being used for aiochastic signal processing techniques are used, pro- calculating burnup and maximum fuel-plate temperatures gressed well. and for the prediction of new core loadings. A calibration facility for nuclear instrumentation in SAFARI-1 Control-rod calibrations and gamma-heating measurements was completed. A stochastic signal generator for reactor- were carried out as and when required. signal simulation was also completed. Three major experimental facilities were operated inter- mittently. These were the neutron-beam facility in beam tube Minicomputer and CAMAC systems 1, the out-of-pile neutron-radiography facility in beam tube 4, A minicomputer-based CAMAC system for the control of a and the neutron-diffraction facility in beam tube 5. Work on sample changer, a wire scanner, and the processing of the cryogenic irradiation facility was terminated. The use of multichannel-analyser data used for neutron-flux calibration, the remaining irradiation facilities, such as the hydraulic and made good progress. A comprehensive computer system pneumatic rabbit systems, the poolside isotope rack and the consisting of a network of instrumentation-control computers, in-core irradiation facilities, for isotope production and SABUS microcomputers and a minicomputer for the collec- activation analysis, continued on a routine basis. tion of quality-control information was commenced and good progress was made. Electronic Engineering A minicomputer system for the collection and analysis of General vibration data is also making good progess. The system Electronic Engineering is a self-financing Department of utilises rapid CAMAC wave-form recorders and sophisticated NUCOR. The Department is involved with the following user-orientated software for data collection and display. aspects: Fourier analysis techniques are used for the determination of the modes of vibration of mechanical components during Microprocessor and minicomputer systems operation. Process control and telecontrol systems Nuclear instrumentation Microcomputer systems Electronic apparatus and systems for measurement and control A microcomputer system was completed which conveys Power electronics. samples from an ultrasonic testing machine for retesting or storage. In June 1982 the Department moved into a new building with a floor surface of 4 700 m2 which was erected at a cost of A similar system for the minimisation of scrap in a milling approximately two million rand. process was also completed. 29 In order to support South African industry regarding micro- Manufacture and documentation computer systems, a South African microcomputer standard The manufacturing groups manufactured approximately 1 600 - the so-called SABUS - was adopted. Certain modules of this printed circuits and mounted numerous electronic modules, system are already manufactured in South Africa. A and the wiring of various large installations was completed. development program for the rest of the modules which are Printed-circuit layouts were made and wire-winding programs not available locally, was initiated and the development of were drawn up for numerous electronic modules. various modules was completed. Ten SABUS micro- computers are used in the abovementioned multicomputer project. A further four systems were manufactured during Waste Treatment and Disposal the year. The Chemical Operations Department is responsible for the treatment and disposal of all radioactive waste and other Process control and telecontrol systems waste of a chemical and toxic nature. The control room and cell instrumentation of the Isotope The liquid waste produced on the site contained a total actual Production Centre were completed. Three process-control activity of 354 mCi (alpha and beta). systems, in which programmable controllers, inter alia, are A volume of 515 564 m:l of effluent was discharged into the used in one of the systems, and microcomputers in the other, Crocodile River. This effluent contained an actual activity of made good progress. 115 mCi, which constitutes less than 3,5 % of the total activity A number of temperature profile controllers for a chemical which may be discharged to the Crocodile River in terms of process plant were also completed. the permit issued by the Department of Environmental Affairs. The replacement of the process instrumentation at the Water Only two of the four sections of the planned disposal facility Works with a programmable controller also made good progress. for uranium-contaminated calcium fluoride sludge were con- structed and subsequently commissioned during March 1983. The Department was consulted on various occasions with Ultimately, this facility will have a volume capacity of regard to the erection and commissioning of new process plants. 3 1 008 m . i. General electronic apparatus A total of 145 tn;i of medium-active (MA) waste was chemically treated and subsequently evaporated in the MA-waste Work was carried out on the electronics for several metallur- evaporator. gical testing apparatuses to test the creep and strength of materials; this work is nearing completion. The resulting evaporator concentrate was solidified. Ninety- six units were processed and the net mass of the concentrate Electronic engineering aspects of the tokamak which was solidified amounted to 9,4 t. The Electronic Engineering Department continued its work A mass of 16,8 t of solid waste was compressed in the baling on the tokamak. This comprised various tasks, such as press and a volume-reduction factor of 5,2 was achieved. changes to the discharge cleaning process, the design, A volume of approximately 22 m3 of solid radioactive waste, manufacture and installation of a voltage filter for one of the including decayed sources, were received from outside control coils of the tokamak, the design, manufacture and organisations for disposal. testing of protective circuits for the toroidal-field power supply and the measurement of stress in the toroidal field coils. One thousand seven hundred and forty-two drums containing solidified, incompressible and compressed waste, together Special diagnostic apparatus, such as thermocouple with a large quantity of incompressible low-level waste, amplifiers. X-ray detector circuits and new CAMAC modules wrapped in polythene, were buried in the disposal trenches on for the on-line computer system were developed. Radiation Hill. A project was also commenced for the feedback control of the Two hundred and eight items, consisting mainly of cropped position of the plasma in the tokamak toroid. fuel element ends, were transferred from the reactor storage pool to the long-term underground disposal facility on Electronic and process maintenance Radiation Hill. The Department carried out the maintenance of the approximately three thousand electronic apparatuses on the Decontamination Services site. About one thousand-tasks were handled by the Electronic Four hundred and twenty-nine items were success- Maintenance Group during the past year. Various calibration fully decontaminated; site decontamination work was services were also rendered. also undertaken. The Process Maintenance and Construction Group continued The active laundry continued to operate satisfactorily and the maintenance of the instrumentation in process plants on 74 051 items were handled. Repairs were carried out where the site and various changes and improvements were made to necessary. A Daikin air-conditioning unit was installed in instrumentation. Various extensions to public-address and the laundry and successfully • commissioned during security systems were also made. September 1982. 30 Supply Services A large number of samples of borehole water were analysed for macroelements on behalf of the Geology Department. Production figures are as follows: Of the total 20 432 samples analysed, the largest portion was 1981 1982 - 1983 in connection with water supply and the monitoring of urine Domestic and process water 803 US 960 ue for traces of uranium. Drinking water 57,2 M^ 49,7 ue Demineralised water 8,97 UB 9,58 Ul Engineering Services Liquid nitrogen 962,0 t 1 262,3 t The Department continued, as in the past, to render the basic Compressed air ±15 nvVmin ±15 nv'/min engineering services to NUCOR, viz. maintenance and con- The 220 m;' domestic waterreservoir which feeds the B-site's struction, manufacture, design and handling of projects. However, the emphasis this year was not, in the first place, on emergency cooling-water supply system, was commissioned, the technical aspects of this service, but, with a view to the during November 1982. target of self-financing, the financial aspects of activities were The newly established borehole station No. 7 was commis- given much attention. The following points became clear and a sioned towards the end of March 1983. Borehole No. 6 will be start has already been made with efforts to bring about savings. relined and restored to its original depth, which had been reduced by approximately 24 m as a result of a cave-in which Concerning construction and projects, the role of Engineering occurred somewhere within the decomposed shale stratum, as Services remains limited to tasks which can be carried out soon as borehole station No. 7 is found to be operating more effectively by an internal group or where security has a reliably. role. This also applies to the manufacturing workshops. The Tegnon RHL 1000 heatless compressed air drier, which These limitations on turnover, especially seen in the light of replaced the inadequate Hiross-Denco unit, was commis- the large variety of work to be carried out, sometimes make it sioned during December 1982. very difficult to utilise available facilities efficiently. It impedes the task of competing with outside organisations which can Process Development specialise in limited directions. It is necessary to determine the optimal turnover for the manufacturing and construction A pilot plant for the chemical treatment of industrial effluent groups. was designed and is being erected. The diverse nature of the work, which varies from sophisti- Because of the very stringent release specifications for certain cated precision work to simple, rough work, requires a great chemical elements and compounds, it became necessary to adaptibility in the systems which are applied. The manufac- treat NUCOR's industrial effluent to the Crocodile River to turing process of a pressure vessel, for example, requires the remove these elements and compounds. closest control over material provision, over each step in the The pilot plant was designed to handle 120 m;! of effluent per manufacturing process, and over the associated documenta- day and it can be operated in such a way that design tion. A procedure which is adequate in such a case will be parameters for a full-scale purification plant can be determined. hopelessly uneconomical for most of the everyday tasks. Although procedures have already been adapted to this in a Analytical Services limited way, attention will have to be given to the financial implications of procedures and specifications. The analyses can be divided into three major groups: Designing has always been an expensive process, especially (a) monitoring analyses in connection with water supply; because the drawing work takes so long. In March 1983 a (b) monitoring analyses in connection with effluent control, computer-aided design system with locally developed both for radioactive and industrial waste; and software was acquired. The system promises to meaningfully (c) analytical services to other Departments of NUCOR lower the design costs. This will also mean that the best and UCOR. designers, with their specialised expertise, can now be much better utilised. The system will be monitored very closely to The comprehensive building programs which are still being determine the actual saving. carried out result in a continuing high demand for specifi- cation analyses of alloys. There are a large number of satellite workshops and drawing offices which have arisen over the years to render a rapid and Type of analysis Number of samples analysed convenient service. With the cooperation of the various 1981 1982 - 1983 Departments where these facilities are situated, it will have to be determined whether financial and technical justification Alloy specifications 1026 1 333 exists for centralisation. Atomic absorption 244 803 Wet-chemical analysis 563 345 The hourly rates for artisans are high, especially because of Radioactive waste 3 236 3 074 insufficient knowledge and skill. A great effort is being made Water 6 350 6 844 to increase productivity through training and encouragement. Uranium 368 299 Most of the equipment in the machine workshop is obsolete, Urine 6 048 7 734 with the result that productivity is low. As funds become TOTAL 17 835 20 432 available, machine tools are rebuilt and digital-display units 31 installed, which will not only increase productivity, but will of terminals and completely eliminates the need for punch reduce calculation errors by the artisan. However, this is only cards. An interactive query program coupled to a very modern a partial solution. It remains essential that modern equipment data-base system, can handle any ad hoc enquiry. be gradually acquired. Machine tools are so much easier to The minicomputers are coupled by means of a high-speed operate these days and require so much less from the artisan communication channel and can also be coupled to the main- that they will, to a large extent, be able to compensate for the frame computer. shortage of experienced, skilled artisans. The stores control system is being developed jointly by Computing Sciences NUCOR and the supplier of the minicomputer and, on completion, will be one of the most comprehensive systems in The Computing Sciences Department has experienced an the world. exceptional period of expansion in respect of computer facilities and services to other Departments. Because of the shift of the administrative work load from the main-frame computer to the minicomputer and the applica- An extensive study of computer-aided design and manu- tion of tuning methods, the Computing Sciences Department facturing led to the purchasing of sophisticated equipment for was able to improve appreciably the throughput and turn- this purpose. The system is supported by a powerful mini- around time of scientific programs. computer, and the available software enables designers to produce two- and three-dimensional design in up to seven A Division of this Department is at present giving attention to different colours. structure analysis and the use of finite-element calculation techniques in the evaluation of stresses and distortions which The manufacture of parts by means of numerically controlled arise in components. Software purchased from abroad is used lathes and milling machines is supported by' this computer for this purpose. system and will be of very great value for NUCOR. The development of neutron data and computing techniques Another facet of this computer system is the three-dimen- suitable for the evaluation of light-water reactors was con- sional analysis of pipe networks and structures by means of tinued. A study of resonance self-shielding and Doppler finite-element techniques. broadening of resonances produced valuable results and will The need for improved computer equipment in respect of be included in the computer programs being developed for the financial control, personnel information and control of store licensing of light-water reactors. withdrawals led to the installation of two powerful mini- In-service training was continued to school personnel in system computers which will serve various video terminals and line printers. programming, system analysis, computer operation and reactor physics. A scientist is undergoing postgraduate train- Software was purchased which handles data-entry by means ing in reactor technology at the University of California. 32 LIAISON AND INFORMATION Scientific Gatherings The following scientific gatherings were attended by officers of NUCOR. At those marked with an As one result of the restructuring of State-financed nuclear asterisk, papers by NUCOR officers were presented. activities with effect from 1 July 1982, the more important * Fifth Symposium on X- and y-RBy Sources anil Applications, University of Michigan, USA (,Kme lasil responsibilities of the External Relations Division were taken • International Conference on Applied Mineralogy intheMmeral Industry: ICAM'81, Johannesburg over by the AEC. These comprise the involvement of the |.Iunel981) Division in international affairs, such as unilateral and multi- * Geological Society of South Africa, Meeting, Johannesburg (July 19B1) lateral agreements, all matters relating to the International " International Conference on Radiation Hazards in Uranium Mining: Control. Measurement and Medical Aspects, Denver, Colorado (October 1981) Atomic Energy Agency and communication with the Depart- * Onion Symposium PPECB, Cape Town lOctober 19B1) ment of Foreign Affairs and Information and other Govern- ment Departments. Relations with the press and other media * SAAPOST's Sixth Biennial Congress "Feeding the Nation". Cape Town (October 1981) are maintained. The name of the Division as it was on * SAAS Symposium, Pretoria (October 1981) 30 June 1982, viz. External Relations, was changed back to South African Apple Producers' Association, Meeting, Stellenbnsch lOctober 1981) the name which it bore some twenty years ago, i.e. Liaison and * Pretoria Women's Club, Meeting, Pretoria (February 1882) Information. As a service department it renders language, Symposium on Mans Spectrometry. Kempton Pork (February 1982) " South African Association of Physicists in Medicine and Biology. 2lt,t Annual Congress, library, reprographic and photographic services; it also makes Rloemfnntein (March 1982)

arrangements for overseas visits by personnel and for group * Pittsburgh Conference on Analytical Chemistry, Pittsburgh (March 1982)

visits to Pelindaba. International ENS/ANS Conference: New Directions in Nuclear Rnorgy wl(h Emphasis on Fuel Cycles, Brussels lApril 1982)

* APCOM Symposium: The Application of Computers and Mathematics in the Mineral Industry, International Cooperation (lolden, USA (April 1982) * Council of Mining and Metallurgical Institutions, 12th Congress, Johannesburg (May 1982) South Africa was again represented on a number of occasions Seminar on Reference Calculations in Thermal Reactors, Rronkhavcn (May 19821 at international meetings on nuclear science and technology International Cancer Congress. Sao Paulo (May 1982) and resource evaluation. * American Institute fnr Food Technology, 42nd Meeting, Las Vega». U11A {June 19821 Fourteen representatives (two from the AEC, three from ' Mango Growers' Congress, Nelspruit (-June Ï08ÜÏ UCOR and nine from NUCOR) under the leadership of Dr ' SAAFOST Panel Discussion, lannclo Uune 1982) J.W.L. de Villiers, Chairman of the AEC, attended the IAEA * Symposium on Uranium Exploratinn Mcthnils: Review on the NBA/IAEA R ami D Program. Paris Uunc 1982) International Conference on Nuclear Power Experience in Annual Conference of the American Nuclear Society, Los Angeles (June 1Ü82) Vienna, Austria, in September. The Managing Director, Dr ACHEMA Congress and Eihihition. Frankfurt (.June 19821 J.P. Hugo, and the Manager: Liaison and Information visited High-Energy Conference, Paris (July 1982) Chile on the invitation of the Chilean nuclear authorities in January 1983. • Coastal Ecology for Engineers - Short Course, Stcllcnbosch (July 1982) a Groundwater '82 Symposium, University of the Witwatersrand, Johannesburg (July 1982) South Africa's expertise was once again invoked more than • Seventeenth Annual Seminar on Theoretical Phvsics, Stellenhosch (July 19821 once by the IAEA by way of invitations to experts to serve on * South African Institute of Phvsics. 27th Annual Congress, .Stellenhosch (July 1982) advisory and working groups. * Thirty-first Conference on the Application of X-ray Analysis, Denver, Colorado (August 19H2I * The Reliability nf Inspection : NDT '82, University of York, England ISeptemher 19821 Meetings of the Steering Committee and the Working Group IAEA Conference on Nuclear Power Experience, Vienna (September 1982) on Uranium Resources of the Nuclear Energy Agency (NE A) International Conference on NucIearData for Science and Technology, Antwerp (September 1982) of the Organisation for Economic Cooperation and Develop- International Conference on the Safety of Thermal Reactors, Chicago ISpprember 1982) ment (OECD) and the International Atomic Energy Agency International Meeting on Radiation Technology, Grenoble (September - October 1982) (IAEA), were attended and regular contributions were made. The Working Group publishes a two-yearly report on the * Course on Safety and Reliability Assessment. Pretoria (Octoher 1982) uranium resources, production and demand of the Western " S2A;,V (Preturia Branch). Meeting._Pretoria (October 1982) World. The next edition of the report which will, as usual, " South African Association for Non-Destructive Testing, Meeting. Johannesburg (Octoher 1982) International Symposium on Nuchter Power Plant Control and Instrumentation, Munich contain details of South Africa's resources, will appear in (October 1982)

December 1983. A contribution was also made to the project * Meat Symposium, Pretoria (November 1982)

which evaluates the speculative uranium resources of the IFAC : Cnnference on In-time Data, Munich (November 1982)

world. Meetings of the NE A/IAEA Joint Expert Group on American Chemistry Association, Symposium on the Geochemical Behaviour of Radioactive Research and Development in the Field of Nuclear Geology Waste. Seattle (March 1983) was attended regularly and contributions were made in ASME Seminar, London (March 198.1) various fields. South Africa also participated actively in a number of geologically orientated international cooperative projects sponsored by the IAEA. The most important of these Visits to Pelindaba was the correlation of uranium provinces on both sides of the Public interest in the activities of the National Nuclear South Atlantic Ocean and the compiling of textbooks on the uranium potential and the geology of the younger surficial Research Centre continued. Some 1 140 interested persons, deposits, as well as on the sandstone and quartz-pebble including science students and scholars, were received on site conglomerate formations of the world. An evaluation of the during the year under review. Apart from various visits uranium potential of a variety of rock types in Northern Chile arranged for local scientists, numerous overseas visitors was completed at the request of the Chilean Atomic Energy including press representatives and television teams were Commission. also received here. 33 Library and Information Services South Africa, especially in the field of library cooperation. Liaison is also maintained with IAEA member countries As the national centre for information on nuclear science and participating in the International Nuclear Information System technology, the NUCOR Library caters for the literature and (INIS), and with the INIS Head Office in Vienna. The information needs of staff of NUCOR and UCOR. The activities of the INIS Liaison Office also include the indexing literature needs include the supply of the following: con- and bibliographic description of all conventional and non- ference and symposia proceedings, patents, standards, conventional nuclear science literature published in South research reports, press clippings, books, periodicals and Africa. This information is placed on magnetic tape for other non-conventional literature. eventual distribution in the Syatem by the INIS Head Office in Vienna. The information needs are either of a bibliographic or factual nature. Scientists, engineers and technicians are kept in- In the year under review (82-01-01 - 83-03-31), 104 457 formed on a daily basis of the latest bibliographic references reports were received. A total of 574 705 reports are now of all relevant literature. Services to the users include, inter available in the Library. During the period, 2 424 new books alia, the following: a Current Awareness Service, a computer- and 3 603 volumes of bound periodicals were added to the ised Selective Dissemination of Information Service (SDI), a collection. Bound periodicals now total 33 080, The total computerised retrospective retrieval of information on any book stock of the Library now stands at 639 799. Publications relevant aspect of science or engineering, an interlibrary loan loaned to other organisations totalled 3 603, while 44 152 were loaned to members of staff. Of these latter, 6 184 were service and all other standard library services. borrowed from other libraries. Altogether 516 392 photo- General liaison is maintained with the library profession in copies and 35 193 printouts from microfiches were made. 34 LICENSING The analyses to investigate the behaviour of the plant under seismic loading conditions for a range of incident seismic wave The Licensing Branch of the former Atomic Energy Board is motions (travelling waves) have been completed. The results responsible for ensuring implementation of the Nuclear indicate that the behaviour of the Koeberg foundation system Installations (Licensing and Security) Act, Act 43 of 1963 as will not differ significantly from that of a comparable "con- amended, and the regulatory functions associated with the ventional" foundation system for the design level of earth- Act, and also for establishing and maintaining a national quake. Studies have continued on the levels of response and system of accounting for and control of nuclear material. In analyses of selected plant components, piping and supports addition it is responsible for regulatory control of fabricated under the design-basis earthquake. For the extreme seismic radioisotopes for medical, scientific, agricultural, commercial conditions considered possible at the site, studies have shown or industrial uses. When the Nuclear Energy Act, 1982 (Act levels of seismic motion higher than those arising from the 92 of 1982) took effect on 1 July 1982, the Licensing Branc» design-basis earthquake and studies are progressing at the was transferred as a unit to the Atomic Energy Corporation of University of Cape Town to test the response of the plant South Africa Limited. structures under extreme loadings.

Licensing activities in connection with Units 1 and 2 of The stability of the essential cooling-water system galleries ESCOM's Koeberg nuclear power station and the uranium under the design-basis earthquake has been found to be satis- enrichment plant at UCOR are currently the major projects factory from the studies performed, but further analyses will within the Branch. The Branch also handles licensing require- be made to ascertain the limits for the stability of the galleries. ments for nuclear-powered ships and ships carrying nuclear- hazard material whenever these enter South African waters During the period of this report efforts continued to be and harbours, and, in addition, a numher of smaller projects directed towards assessment of radiological protection provi- are handled. sions for the Koeberg nuclear power station. Aspects that received further attention were the emergency plan and the Koeberg adequacy of the emergency control centre, effluent control procedures, environmental survey procedures, personnel Design criteria have been established for all major safety dosimetry, instrumentation, shielding, waste-storage facil- systems and plant technical specifications are being assessed ities, medical aspects, radiological aspects, primary circuit against these criteria together with the operating procedures. contamination and a host of other aspects associated with This is to ensure that the plant can be operated in a safe radiological protection. manner during normal and abnormal conditions. All major components of Unit 2 have been delivered and site Studies continue with regard to the adequacy of the Ultimate installation of these is almost complete. Equipment and facil- Heat Sink. ities for the handling and storage of fresh fuel in the Unit 1 fuel A considerable improvement is now evident in the flow of building were commissioned and a licence was issued on 1 technical information and, as a result, the licensing program June 1982 to permit the receipt and storage on site of has been accelerated in order to avoid any delay in the sufficient fuel for the first core loading. The Branch's three project program. resident inspectors have continued to monitor the construc- tion and commissioning activities, including pre-service Reports on tests conducted during the early stages of inspection, with supporting visits by inspectors from commissioning have become available in considerable Pelindaba. numbers and are currently being examined. The results of these tests are expected to confirm the adequacy of the The training of ESCOM staff has been monitored and "as built" plant. licensing examinations were commenced in respect of the first 21 candidates for the categories of reactor operator and senior A comprehensive review of all safety-related aspects of the reactor operator. primary circuit continues. A detailed and ongoing assessment cf the conservatisms Uranium Enrichment Plant (UCOR) involved in quantifying radioactive releases resulting from The Branch has continued to monitor the safety-related postulated nuclear accidents has been initiated. The pre- aspects of the construction work, the extensions to the pilot liminary indications are that previous theoretical estimates of plant and also to monitor the operation of the pilot plant to releases may have been overestimated by an order of verify compliance with licence requirements. magnitude. Information Systems A study is in progress to establish the magnitude of the uncertainties involved in frequency estimates of the occurr- Subsidiary arrangements to the safeguards agreement for the ences of nuclear accidents. Koeberg nuclear power station and the revised subsidiary arrangements to the safeguards agreement for SAFARI-1, in Studies on the various aspects of the core design have raised a the preparation of which the Branch had been actively large number of questions which have been discussed with involved, were completed and approved by the IAEA. ESCOM and the contractor. The information required to Records of nuclear material continued to be compiled for the answer the questions is currently becoming available and will National System of Accounting for and Control of Nuclear be studied. Material. 35 Generic Activities Control of Radionuclides A comprehensive research program on fracture mechanics There was a substantial increase in the number of radio- concerned with the integrity of reactor pressure vessel steels nuclide users during the period, especially in respect of has continued in conjunction with the University of the industrial applications. Authority was granted to a private Witwatersrand. The main objective of the research is to concern for the use of 50 kCi 6nCo in a commercial food understand the effects of variations in microstructure on irradiation plant, after a thorough investigation of the radia- materials strength and wet crack growth during fatigue in tion safety of the facility. unirradiated and irradiated reactor steels, with respect to Inspections were carried out at the premises of users of operational life. radionuclides in the Eastern and Western Transvaal. A firm basis is being established for understanding the Assistance was given by personnel of the Licensing Branch to generic problems of human reliability, and in this respect a the Pretoria Technikon in February, March and May in the number of topics are being researched, including analysis of presentation of specialised courses in industrial radiography. the human factor in the application of quality assurance codes and procedures. Psychometric test batteries and high-stress indicators for use in human reliability assessment of nuclear General plant operators were developed. The Branch was actively involved in the drafting of the regulatory aspects of the Nuclear Energy Bill, necessitated by Feasibility studies in the use of nuclear simulators for human the re-organisation of the State's nuclear interests, which was reliability risk studies are continuing. tabled in Parliament in May 1982. A study of perceived risk, undertaken by the Rand Afrikaans Owing to a continuing staff shortage, the Branch has again University on behalf of the AEC, has reached an advanced engaged the services of consultants in order to provide stage. A nation-wide questionnaire on this subject is nearing expertise in specialised areas and also to augment its existing completion, and from this it is proposed that a criterion for workforce. In respect of the latter, the principal additional perceived risk will be developed. effort was applied to the analysis of Koeberg safety systems. 36 Prior to the incorporation of NUCOR, the last amendment to ADMINISTRATION the Atomic Energy Act, 1967 (Act 90 of 1967), was effected NUCOR's administrative and related matters are the in 1981. responsibility of the Finance and Personnel Departments, and the Central Administration, Legal Matters, Security and Patents Auxiliary Services Divisions. The patent provisions of the Atomic Energy Act, 1967 (Act 90 Since the establishment of the AEC on 1 July 1982, NUCOR of 1967), are now contained in sections 55 to 66 of the Nuclear has also, in general, handled these services on behalf of Energy Act, 1982 (Act 92 of 1982). All rights and obligations the AEC'. of the former Atomic Energy Board in respect of patent matters were automatically transferred to the Atomic Energy Meetings Corporation of South Africa Limited and all inventions already patented became the property of the AEC, The AEB Board and its Committees Period of 1 January to 30 June 1982 The AEC has delegated the administration of its patents, and The Board met twice, while its various Committees came all matters relating thereto, to NUCOR. together seven times. Services The NUCOR Board and its Committees Period of 1 July 15)82 to HI March 198.'* Transport, gardening, cafeteria, cleaning and telephone services wore again mmntititu'd nl n satisfactory level. The Board met three times, while its various Committees came together six times. Finance Prospecting for Source Material and Regula- Because of the establishment of the Atomic Energy Corpora- tory Control tion i-f South Africa Limited on 1 July 1982, the accounts of the Atomic Energy Board had to be closed on 30 June 1982. The Minister of Mineral and Energy Affairs approved one These accounts were audited by the Auditor General and application for prospecting for source material during the found to he in order. From 1 July 1982 the firm Theron van ahovementioned period under section 5 of the Atomic Energy der Poel was appointed as auditors for NUCOR and the Act, 1967. financial systefri was adjusted with their cooperation to comply with the requirements of the Companies Act. The Legal Matters accounts were changed over from those for a statutory board to company accounts, which brought a number of problems On 1 July 1982 the Nuclear Energy Act, 1982 (Act 92 of to light. 1982), was enacted. In terms of the provisions of the aforesaid Act the Atomic Energy Corporation of South Africa Limited In view of the above, the Finance Department was reorganised (AEC) was established on the same date, with the power to to cope with the abovementioned problems. establish subsidiary companies in order to, infer alia, accom- modate the provisions of section 83(4) of the aforesaid Act. Personnel Simultaneous to the enactment of the Nuclear Energy Act As part of the "parity exercise" between UCOR and NUCOR, 1982, the Atomic Energy Act, 1967 (Act 90 of 1967), the it was decided to use the Peromnes post-evaluation system. Uranium Enrichment Act, 1970 (Act 33 of 1970) and the Members of Top Management and Heads of Departments Nuclear Installations (Licensing and Security) Act, 1963 (Managers) followed training sessions, and six evaluation (Act 43 of 1963), were repealed. committees were formed from these groups. Since January On 1 July 1983 the Nuclear Development Corporation of SA 1983,460 target posts have been evaluated. These posts were (Pty) Ltd (NUCOR) was incorporated as a subsidiary com- selected because they are typical and representative, and pany of the AEC in terms of the provisions of the Companies virtually the entire spectrum of posts through the organisation Act. 197,1) (Ac-t61 of 1973). By resolution the AEC transferred was covered. most of the assets, liabilities, rights and obligations of the A final profile of the relative value of NUCOR's posts in former Atomic Energy Board to NUCOR. comparison, firstly, with those of UCOR and, secondly, with Section 83(9) of the Nuclear Energy Act, 1982 (Act 92 of those in the entire labour market, will shortly be worked out. 1982), provided that anything done under any provision of a The posts of Managers and Heads of Divisions will be law repealed in terms of subsection (1) of section 83 of the evaluated later. Nuclear Energy- Act shall be deemed to have been performed The success with which the system was implemented is mainly by NUCOR under the corresponding provision of the Nuclear Energy Act. 1982. thanks to the acceptance, interest and cooperation of the line members and members of Top Management concerned. In its day-to-day administration NUCOR, being incorporated in terms of the Companies Act, operates under the provisions Thirty-one bursaries have been allocated for the 1983 of the said Act and exercises only those powers contained in academic year. A total of 24 bursars completed their studies the Nuclear Energy Act delegated to it by the Board of at the end of 1982, 14 of whom joined the service of NUCOR Directors of the AEC. and five continued their honours studies with financial 37 assistance from NUCOR. Another five are continuing 'vith towns like Rustenburg, Krugersdorp and Kempton Park. honours studies at their own expense or with the assistance of Outstanding results were achieved. unrelated bursaries. Advertisements On 31 December 1982, 20 employees qualified for a twenty- year long-service award. Because of the economic recession during the year, a very good reaction to advertisements was received, especially On 31 March 1983 there were 2 434 employees in the service concerning specialised posts. of NUCOR. The table below indicates the numbers in the various categories. The past year was an exceptionally successful recruitment year, and the most important recruitment source for highly Administrative 65 skilled posts was the universities, while the neighbouring Scientific 248 towns accounted for the semi- and unskilled posts. Technical 768 Experimental 235 Retirement Miscellaneous 699 Learner technicians 336 Retirement on pension Artisans 83 Permanent officers 8 TOTAL JM34 Permanent officers re-employed on a temporary Of the present approved posts for all categories of employees, basis 5 343 posts (12 9? of the total) were vacant on 31 March 1983. Temporary employees 11 Industrial social services were initiated during August 1982. Security Problems handled concentrated chiefly on financial and other social problems of adjustment. The number of cases relating At the beginning of 1982, the Security Division commenced to these problems indicates that this is a service which the first basic training course. Since then, the majority of NUCOR cannot do without. As the service has become members have completed the course with evidently positive known, it has grown steadily. The service will be extended to results. In addition to the basic course, an advanced course include group work with artisans and learner technicians. was also presented to more senior members. This course will, in future, be presented to all members who wish to be pro- During the year under review, 743 persons were taken into moted to higher ranks. service by NUCOR. As a result of the huge expansion of certain projects during the past year, the recruitment group In 1982 two members passed UNISA's Security Management launched an intensive recruitment drive which included, inter Courses and various members have enrolled for the course alia, the following: this year. With the obliging cooperation of the South African Railway Careers exhibitions Police, two members of the Division were trained as Task Various centres in the country were visited, and the Cape Force instructors. These two members have already pre- schools were concentrated on since Transvaal schools were sented various Task Force courses at Pelindaba. The Task covered during 1981. Force, which will act as a reaction unit during hostile attacks, will be formed shortly. Universities During February 1983 three members were trained as patrol Careers exhibitions were also used at the neighbouring dog guides and the establishment of a patrol dog unit can now universities. Visits were also paid to distant universities. commence. Exceptional success was achieved in this and it is a medium As a result of improved service conditions and working condi- which must be extended. tions, the personnel position of the Division improved Recruitment endeavours were also extended to neighbouring measurably during the year under review. 38

'Kruger. J-; Rououw, J.W. Bydrae van nëroaoleienskappe tot moontlike vrylaünü van R LIST OF PUBLICATIONS BY STAFF materiaal uit reaktorsisteme. S, Afr. J. Set (May 1982) v. 78 p. 212-213. Le Roux, J.P.; Toent, P.D. A review nf the uranium occurrences in the Karoo Supergroup of South MEMBERS AND BURSARS* OF Africa. Twelfth Congrensof iheCouncil of Mining^ndMetBUurgical Institutions, ./ohannesburR, NUCOR Mav HIH2. 'Leusehner, A,H,; Roaaouw, J.W.; KniRer, J. Trapping mechaniHtns and build-up nf aerosol *The names of staff members and bursars ofNUCOR appear in particles on large pore filters lined to simulate respiration of aerosols. S Afr. J. Sci (May 1982) bold type throughout v. 78 p. 212. Levin. M. The geology, hydrntnpy and hydrnchemtstry of an area between the Kuruman and Orungc Rivers. North-Western Cape. Trans, (iml Sac. S Afr. (1981) v. 84 p. 177-190. Meyer. B,R,; Peisach, M.: Kotzè. W. F.lementnl study hy PIXE of nutrient elements inapplesduring I. PELINDABA REPORTS (PEL and PER REPORTS) their growth period. Fifth Symposium nn X- and y-Ray Source» and Applications, University of I'Rl.MU: Hofmeyr, C, Hie unkeinralriinwrbinrlinB-KmrEie van 195Pt en 19liPt. Apr 1982 13 p. MichiRnn, USA. .lun. 1981. ISBN u snnriO-Txvn Niemand, >I.G.; Van der Linde, H.J. Shelflife extension of fresh chicken radurisatinn. S Afr. Poultry I'RI. 28! : Hrita, R.J.N.; Van der Westhuizen. CS.II. Environmental rndionc Uvily at the Bulletin (Mnr/Apr 1982). Nntintwl Nirclcnr tWarch Tentre, I'elindahn: Report tor the vrar 1981. Jul 19H2.1S p. O'Mnhony, J.R. Nuclear fusion and the outlook for commercial fusion read nra, 7VnnN, S. Afr. Inttt. ISBN (>-8fi9fin.7-|i>.n l'Kt.-ÜH'i • Cortic. M.B. The cfft-ct of necond-phflse particles «n the corrosion nnti Htructure of Electr. Kng. Man 19811) v. 74(11 p. Ü-6. Z!rralw4. Oct. 1ÜK'.'. s» p. ISBN O.RGDtlO-7-13-1. Piani, C.S.B.; Aspeling, J.C. Activation energy determinations and a cnmpnrisnn nf cnrrelntori recnverv with three-dimenainnal diffusion theory in neutron-irrndiated platinum. S Afr J Phys I'EH-fU - KuHsman. H.M. Pusiuewe kompakte uperalcin; in BiHiuch-ronsters. Apr 19B2. H'i p. ISHN 0-H69IKI-T.14-I1. UBR2I v.MSl p. U7~*:i. PKR-.i" : Brynard, H.J.J Jakob, W.H.O.; l.e Roux, «I.P. The hetiimemoioej'. mineraloRy and Piani, C.S.B.;AipellnE8(i8n. •>:! p. ISBN (1.8lill(ill-74:i-X. thermal and fast-neutron irradiation. Phy\ Lett., A. (Mnr 19H2) v, 88A| p. 2n7~2Rl. I'KR 71 : Le Roux, J.P. The scriimentulogy and uranium mineralisation of the OR-a deposit. Pianl. C.S.B.; Atpellng, J.C, Innchronat recovery in Cn and Cu-Au nfter neutron Irrndintion. I. Lainsshuri! district. AUB IÜ82. US p. ISBN I1-8I«IBI1-74|.8. rnmparisnn after thermnl- nnd fnnt-neuirnn irradiation. Radiat, Eff, UflflHi v, 60 p. 19-28.

PKK-72 : URoux,J.P.The!.edimentolnB.anduraniuinniinerallsatinnoftheMaliieMkloori>rorEni;itiffrs- Short Course, Stellenhosch.Jul 1982. uranium exploration method's: review of the NF.A/IARA R & I) programme. Paris. Jim 1982 'Bevinglon, KM.; Winkler. B.C. LimitiUion Relialnlitv of Inspection : NOT '82, I 'rnnium: South Africn's mineral wealth. Designed and edited hv the Puhlir Relations Department of PimiTMiy of York. Sep liiHi (he Chamber of Mines nf Smith Afrira and the Atrnnir Fnerg\' Hoard of South Africa 'Inhannes- Jtiirs • Chnmher of Mines, of South Afrira. 1982. 20 p. (Chamhtr of Mines of South Africa Brndrivk, H.T.; Thard-Gray, R.I. The effect of irrnHintionon the diseuht-causingorganismsofthi' PR!) -eries ; m. 2«2) tiinncci Snulh African Mnnp> i .wff- Aisacintian Rt-j-earch Rt'pnrr llWJt v. •> p. .17-1». Van Am, D. Kemkras nniiiurhrnutting en natuurbewnring. Woord en Daad (Der 19811 no 2-'12. Rrodrick, H.T.; Thord-Gray. K.S. Irradiation in pcrspeclive : the sifimTieunct' for the mnn^o induslrs- South Africim Man^n firowers AsMn-iiitiim Research Report (H)fi'J) v. '2 p. 'JII-üR. •Van A*. D. Radiological impart or radnn on the population.:? Afr.J Sri. I Mav 1982) v. 7H p. 212 Brodrtck, H.T. Wuvs in whii-h irmcliiition cnultl impmvp the effectivem>ss of ücvernl exUtinj: food Van der .'.inde. H.J. U radnrUation rommerciaiiv feasthle?S. Afr. FnodRev. I Apr/Mnv I!)82) v. 9(21 lireseniitinn proce'.si't in South Africa. S Afr Ftmd Rev. lAnr/Mav Hl«21 v. $[2) p. -l 2-1-?fi. De Jesus, A.S.M. Ktidioisutopes in non-dt'Mrurtive nnjilvws. FWP Journal (Dec 1UH1) p 7-K. K), Van der Merwe. P. du T. Clatsirai c ritntmns of the ronformnllv rnvariant (Üi ey pqualinn. Ph',v ! rj. in ƒ.«•«.. H tNnv 1Ï1H!) v. 48- >-4Hfi. De Villlerx. J.W.U The nurteiir option • a Irmk nt South Africn» power needs, l.vndrrnhip HA Van der Merwe, P. duT. A ftmrtional rafthod rorsiipcrflnid svMfnr* S Afr J Ph\s (1982) \ •"» (Autiimn \W>) v. 111! p. 17. 19. 2K2Ï1. p :(•_•-:(« l)e Wet, W.J. Voedsflhestrnlini! in Suid-Airikn. lMniibnu~lnlii>tinn-ibulti-tin I Apr 198'J) no AR'l. Van der Merwe. P. duT.Niin-linearphnnnn dispersion of condensed matter Phv* Lett,A H9t*ll v.H-JAtHip I1.V417 liu Plesxis. I1, de V.: Van Doorn, C.F.: (Irobler. N.J.S.; Van Uelden, D.C. A nuutrnn sentterinK invia«ti^titjrm »nhi' rriliml exponent ft in (he urnniiim mrmnselenitk1. -/ ƒ'A vs.. Cfl.ondun}, Solid Van der Merwe. P.duT. Sirniiflrnlinnof tuperfluid helium II- l.vlt NunvnVim Mul 19H'.M v. :t4l 111 Shtli't'ltys iV.W2)v. IS p. lrt^5-l*):i». p :i*2V:i2fi Evangelidis. E.A. K(ircii-frccfii'!d>.innthrei'diniensiiiii:ilplaHmat(inis Astmphys Spnci'ScL IlilH'J) Van der Spuy, E. Spnnianmui'Dvmmetrv Krenking E'--- I he elertromngnelii' interaciinn S Afr J v HI p.'J(il-aiiH fh^ llflRU v. 4 |» B:i-|ll2 EvanKeHdU.E.A/rnmcdflNalii(ifinsfif(hefiFEenhauprt't(UHhon.^,«mM>'.v..V^^ VWI der Spuy, E. Tbp »viik iniprarimn rpjjiifd mibeitmnpir)er»rtion NunvnVim. A tOci 19H.M p 117 rjl). v. 71 Aim p. :in.*i-:i:i2 Feant. G.A. The rpliahility of non-desinictive evaluation Course on Safety and R»üahilitv Vui der Weathuizen, M.; Krirmw. K I..: Van der Bank. D.J.: Nnude. <-.R Kvaliiationofn gnmmn- Assessment. I'reliiriu. Oct. liia'J. aitpnuntinn soil water meterand nnrutnin-st-atlerini: meter fnrmeaiuringlnpuiilKalercnntent r'ouché. K.F.; Lessing. J.G.V.; De Koek, N.J. Separation of rhodium frnm indium hy extraclinn Avmrhi'mnphv*irn Il9»li v lit |i 25-29 fnim mnlten cyanide. -J Lrss-Common Met. (1982) v. Rl p. i:ifl-14fi. Van Doorn. C.F.; Van Detder. DC: Du I'lr-is. P de V. Negative evidence nr nnv hi«tnn Geyer. H.B.; Lee. S.Y. Mic scopic structure of on iut crnctinp hoson mode) in terms of the Dyson dependrnre of the NPM temperature nf a I)v rrvntal frnm neutron scattering and ullranonii- 1HI«(HI mapping Phys « •. C (Aue 19H2I v. '26ril p. fi-12-Gül. measurement'., •ƒ Magn. Magn. Mater tl9**2lv 27 p I24-I2fi 'Hamblelon-JoneB, B.B. AnuKticnl nspects in the geochemistry of uranium. Bulletin nf the South •Van Wyk. A.J. t'nmporison «fiome he\wtnbHurvfndinpharmiur«ttticaU. S Afr J Sci iMitv J!»fL'f African Institute nfAssayvn and Analyst* lOct 19HI1) no. 49. v THp 214 IIamhleton-Jones, B.B. Uranium occurrences In the nilrficial depmits of Southern Africa.Twelfth ConKreHK nf the Touncil of Mining and Metfltlurgicnl Institutions, .lohannesliurg. May 19R2. Henning, J.J. On uniform limits in the propagation nfelectramapit'tic waves in a hot pla-sma. Phys III. THESES icr(1982) v. 26 p. 471-474. Cortier, M.B, The effect of second-phase particles r i the corrosion and structure of Zircalny-4. Thesis (M.Gng.), University of Pretoria. 1982. Hodgson, J.L. The licen«ine of nperalurs for nuclear power station*. Course on Safety and Reli- aliilitv Assessment. Pretoria. Oct. 1982. De Klerk, W. The geology, geochemiHtry and silicate mineralogy of the upper critical zone of the north-west Bush veld complex at Rustenburg Platinum Mines. Union Section. Thesis IM.Hc.l, Rhodes University. 1982. Gertenbach, W.P. An investigation into the organisation and structured design of multi-computer process-control systems. Thesis (Ph.D.(Elec.)), University of Natal, 1982. 39

Geyer, B.B. Boson mappings for elementary nciuniaiw in fermion systems. Thesis (Ph.D.t. 2. Oarmehl, I.C. The application nf sequential 99mTc-methylene diphnAphonate HcintiRraphy to University of Stellenhoflch. IBHl. evaluate hone heoliriü ^n nnn-human primatcR. PrnceedinK» Third World Cnngremi nu Nuclear Mrdicineand Btoloiy. Pari», v, 1 p, 1811-187. Kuiunmn, H.M. Posiliewe kompukte aperaiare in Banach-ruosters. Thesis (M.Sc). University of .1. Umrens. D.C.: Donnehl, l.r.; Goose.vD..). The reaKihility nr a renogram fltudy in dogit with Pretoria. 19fll. radkiphannneulical 99roTc-DTPA. J. 8. Afr. Vrt. Asa. (19821 V. S3. no. 1, p. 243-248. Milan, J,J, Die bepaling van rn(tium-226 in die uitskot van (joudmyne en hdlle nrngewings. 4. FalkKon. H.r.; Falbon. Ci.; Portugal, M.; Van der Watt. .!.•!.; Rchneman, K.S. Carcinoemlirynnic Thesis (M.Sc.1.University nf Pretoria. 1982. antigen a» a marker in patients with hreaHtcencerreceivingpofltiiurgicaladjuvantcheinntherupy. Norden, C.E, Modelling and tracer studie» of atmospheric dispersion and deposition in regions of Cancer. (18S2I v. 49, no. 9, p. 1859-lflei. rnmpl" icitwgraphv, Thesis (Ph.D.h University of Natal, 1981. Plant, CS.B, A comparative studv nf the effects (if thermal- and fast-neuimn irradintion on some fi. KritchevRky. D.; Davidson, L.M.; Van der Watt. .I.-I. The influence of carbohydrates on athero- sclerosis in primateR : Metabolic effects nf uiilizaulc dietary carbohydrates. {Rd.) .Sheldon «lecled dilute face centered cuhie alloys. Them» (Ph.D-l, Rand Afrikaans Uni'versiiy, [981. Reimr, Marcel Dekker. Inc. (19fl2| n. Hl-174. Pietcnw, II, Pie stfrndaardinasie van spnnrelemenic in internHsionale hioloRiese verwyainptmale- nalc met Iwhulp van neiitrnnaltliveringsanalise en aioomflbsnrpsiespektrofnlnnielrie- Thesis li. Pitout.M..I.;Louw.W.K.A.:Ijatl,H1-.VanVuuren,C.I.;VanderWatt..l.l.;HuBn.N.Amodified (M.Sc), Knnd AfrikaanH Univcrnitv. 1981, neutrat sucrose centrifugafion method for rapid detection of f)NA damaged hv y-ntdiitxiim nn'l repair in human lymphocytes. Int J. Biachpm. 11982) V. 14 p. HB9-B04. Hindrock, Ttl*. Delerminntion nf Home minor and trace elements in iron oren hy inn exchange rhrnmntofirnnhy, sppctrtiphtitomelry and ntnmic altnurption Hpcclrnmelry. Thesis (M.Sr.t. 7. Pilmit. M.J.i Uiuw, W.K.A.: Hugo, N.; Izatt, H.; Van Viraren, r.,l.,l.; Van der Watt. .1..1, UnWf roily nf Pretorin, lt)7f). DNA damage detection.. Nuch'tir Aclim ami) p. 24-2». 8, Pitout. M..I.: Uww, W.K.A.; Van Vuuren. C..1..I.; Van der Watt, .1.1 Lymphocytes mid radio, suaceptihillty. Nuclear Attice (198,11 p. 29. IV. NUCOR INSTITUTE FOK LIFE SCIENCES !). Yeh. Y.K,; HnnkBH, I..V.; Wemels, I..M, Pyridim' nucleotide metabolism in the erythrocyle nf PUBLICATIONS South African Hlackn with primary hp|iatnma. Ada Vitamiml, Eniynik. 11982) v, 4|:l) p.253-2B6. I. Itarmchl. l.r.; Mennen, l>.; Unraen. 0.1.

NUCOB expresses its very sincere appreciation to all members of its Committees for their valuable contribution to the work and progress of the Committees.

NATIONAL COMMITTEE FOR NUCLEAR RESEARCH GRANTS COM TECHNOLOGY AND RADIATION Chairman Dr J.K. Basson Chairman Dr J,K. Basson Members Prof R.W. Charlton Vice-Chairman Dr W.J. de Wet Dr C.G. Coetzee Members Dr M.G.M. Atmore Dr L.J. Dry Dr S.W.P. de Waal Dr G. Heymann Mr D.C. Farquharson Prof C.J.H. Schutte Dr P. Haupt Prof P.H. Stoker Dr P.R, le Roux Dr J.J. van der Watt Dr P.G. Marais Prof I. van Heerden Prof J.P.F. Sellsehop Prof G.T. van Rooyen Dr L.H. Stein Dr J.S. Steyn Dr D. van As Mr B.C. Winkler

LIFE SCIENCES COMMITTEE WORKING GROUP ON URANIUM RESOURCES Chairman Prof J. Metz AND PRODUCTION Vice-Chairman Dr J..I. van der Watt Chairman Dr P.D. Toens Members Prof J.D. Anderson Members Mr A.C. Haasbroek Dr J.K. Basson Mr K.P. Landman ProfT.H. Bothwell Dr F.A. Camisani-Calzolari Dr W.J. de Wet Mr H.A. Simonsen Prof M. Iturralde Mr P.J. van der Merwe Prof B.C. Jansen Mr R.G. Heard Dr P.G. Marais Prof A.G. Sandison Prof I.W. Simson Prof P.D.R. van Heerden Dr G.I. van Rooyen Prof Nancy van Schaik Mr B.C. Winkler Mr A. Selzer (ex officio)

PATENTS COMMITTEE (delegated to NUCOR by the AEC) Chairman Dr J.P. Hugo, NUCOR Members Mr J.O. Tattersall or his alternate, AEC Dr R. van der Walt \ NUCOR Dr N.P. Pienaar ƒ Dr J..I. Wannenburg \ UCOR Dr R.S. Loubser ƒ Ad hoc members Mr H.A. Simonsen, MINTEK The Registrar of Patents or his alternate Ex officia Adv H.L. Breedt, NUCOR Secretary Mr A.J. Laubseher, NUPOR Printed and published by NUCOR, PELINDABA Private Bag X256 Pretoria 0001

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