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NATIONAL REPORTS

Nuclear verification in

Verifying South Africa's declared nuclear inventory, and the termination of its weapons programme, was a complex task

by Africa's accession to the Treaty on the terial involved in the programme had been recov- Adolf von Non-Proliferation of Nuclear Weapons (NPT) on ered and placed under safeguards. Baeckmann, 10 July 1991 was promptly followed by the sign- Over the months that followed, the team Garry Dillon, and ing of a comprehensive safeguards agreement with thoroughly examined detailed records and veri- Demetrius the IAEA on 16 1991. Four days later, fied the inventories of nuclear materials in South Perricos the IAEA General Conference adopted a resolu- Africa. As a result, it was able to conclude that tion aimed at ensuring early implementation of there were no indications to suggest that the the • safeguards agreement and verification of initial inventory is incomplete or that the South the completeness of the inventory of South Af- African nuclear weapons programme had not rica's nuclear installations and material. been completely terminated and dismantled. In 1991, a team of senior IAEA This article highlights the IAEA's verifica- safeguards officials specially appointed by the tion activities in South Africa and the main ac- Agency's Director General carried out the first tivities associated with its assessment of the ter- inspections under the comprehensive safeguards mination of South Africa's former nuclear weap- agreement. The activities to verify the correct- ons programme. ness of South Africa's declared inventory of nu- clear material extended over several months and involved long-established measures. These in- Verifying the correctness of South cluded the examination of contemporary operat- Africa's declared nuclear inventory ing and accounting records, and analysis of the nature and quantity of nuclear material. South As required under the comprehensive - Africa's extensive made the guards agreement, South Africa submitted to the task complex, requiring considerable inspection IAEA an initial report of its nuclear programme. resources and extensive co-operation from South The initial report is a comprehensive document and African authorities regarding the provision of includes quantitative data on all types of nuclear access to defunct facilities and historical operat- material, on a facility-by-facility basis. It is ex- ing records. panded by attachments which provide detail on the The task was further complicated when, on location and the number of items of nuclear 24 March 1993, State President de Klerk an- material contained in each respective facility. nounced that South Africa had developed and For the IAEA, it was therefore possible — on subsequently dismantled a "limited nuclear de- the basis of the data contained in the initial report terrent capability" involving the design and and subsequent inventory changes — to establish manufacture of seven gun-assembled devices. an itemized list of each facility' s nuclear material The news prompted the IAEA to augment its inventory. Verification of such itemized lists was safeguards team in South Africa with, among carried out during the first few months of the other specialists, nuclear weapons experts. The implementation of the comprehensive safe- team's assignment was extended to include as- guards agreement. This was done in accordance sessing the status of the former nuclear weapons with the requirements for physical inventory programme and ascertaining that all nuclear ma- verification (PIV) specified in the IAEA 1991-95 Safeguards Criteria, using established account- ancy verification measures. Mr, von Baeckmann is a former Director in the IAEA Depart- Unlike other States which had entered into ment of Safeguards. Mr. Dillon is a senior staff member of comprehensive safeguards agreements, South the Department now serving as Deputy Leaderof the IAEA's Action Team, and Mr. Perricos is Director of the Depart- Africa had been operating a number of nuclear ment's Division of Operations (A). facilities, of unique indigenous origin, that pre-

42 IAEA BULLETIN, 1/1995 NATIONAL REPORTS

viously had not been subject to safeguards. De- tails of their design and operation were thus rela- South Africa's nuclear installations tively unknown to the IAEA at the time the comprehensive safeguards agreement was con- cluded. (See box.) This situation made it necessary to devote Installations under IAEA safeguards which were formerly inspected in accordance with an considerable effort to understanding the facility INFCIRC/66-type safeguards agreement processes. This would enable establishment of workable safeguards approaches for interim im- • SAFARI-1 , Atomic Energy Cor- plementation during the period in which the fa- poration, Pelindaba cility attachment would be negotiated. This proc- • Hot cell complex, Atomic Energy Corporation, ess was facilitated through a joint seminar. The Pelindaba • Koeberg nuclear power reactor units 1 and 2, meeting provided the opportunity for the IAEA Electricity Supply Commission to explain the accountancy procedures appertain- ing to a comprehensive safeguards agreement (INFCIRC/153-type) and for the South African Additional installations under IAEA safeguards State System of Accounting and Control (SSAC) since September 1991 in accordance with a and facility operators to provide insight into the comprehensive safeguards agreement facilities and their operating procedures. (INFCIRC/153-type) Since the time of the " initial inspections" in Uranium conversion.uranium hexafluoride (UF6) late 1991, verification activities carried out in production plant South Africa have continued to be based on the highly enriched uranium (HEU) enrichment IAEA 1991-95 Safeguards Criteria. In October plant (Y-plant), now defunct 1992, a near-simultaneous PIV, involving all South HEU storage facility HEU-UF6 and metal/alloy production plant African facilities, was successfully carried out. All HEU fuel fabrication plant quantity goals were attained during that first mate- Semi-commercial low-enriched uranium (LEU) rial balance period. Similar exercises were car- enrichment plant (Z-plant) ried out in August 1993 and October 1994. MLIS laser enrichment R&D facility As might be expected, it proved necessary to LEU fuel fabrication plant Natural uranium/ metal plants ' make a number of corrections to the data in- Decontamination plants cluded in the initial report. This resulted from the storage compound continuing efforts of the SSAC to ensure the Locations outside facilities accuracy of the data, errors identified during the inspection process, and corrections to estima- tions resulting from measurements made by fa- A practical basis was established through cility operators after issuance of the initial report. which the mutual consistency of the inventory This latter aspect was particularly relevant in the of nuclear installations and material — and case of material recovered as a result of decon- hence their completeness — could be deter- tamination of plant components. mined. The declared inventory was first evalu- At present, facility attachments are in force for ated with respect to production, imports, and six facilities and it is intended to complete negotia- usage. Then the isotopic balance of the inventory tions for the remaining facilities during 1995. was calculated and compared with its natural uranium origin. Through this process, the declared inventory Assessing the completeness of South was found to be consistent with the declared Africa's declared nuclear inventory production and usage data, but the calculated isotopic balance indicated " apparent discrepan- An important aspect of the IAEA's safe- cies" with respect to the highly enriched uranium guards implementation in South Africa was the (HEU) produced by the defunct pilot enrichment assessment of the completeness of the declared plant (called the Y-plant) and with respect to the nuclear inventory, which is extensive. The com- low-enriched uranium (LEU) produced by the plex task was carried out as a separate exercise semi-commercial enrichment plant (called the by a team of senior members of the IAEA De- Z-plant). The direction of these " apparent dis- partment of Safeguards specifically appointed crepancies" could be interpreted to indicate that for the purpose by the Director General. It re- an amount of uranium-235 was unaccounted for. quired considerable inspection resources and co- Having regard to the period of time involved operation from the State authorities regarding the (for the Y-plant in particular) and the absence of provision of access to defunct facilities and his- accurate accountancy of the depleted uranium torical operating records. waste stream, such "apparent discrepancies"

IAEA BULLETIN, 1/1995 43 NATIONAL REPORTS

As part of its assessment of the status of South Africa's former nuclear weapons programme, a team of IAEA inspectors were able to visit all facilities once connected with the programme. Shown here are the secured vaults at the /Circle facility, where the weapons were produced and stored (top and below);the general purpose critical facility that was dismantled near the AEC Pelindaba site (lower left); and IAEA inspectors outside the building (left) over the Kalahari test shaft, which was

rendered harmless (facing page). (Credits: v.Mouchkin, IAEA:AEC>

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were not unexpected. It was, however, consid- ered necessary to continue efforts to further clar- South Africa's former nuclear weapons programme: ify them, with priority being given to the Y-plant Chronology of the main events data. Further examination of records, particu- larly those covering the recovery of HEU mate- rial following the shutdown of the plant, resulted in a significant reduction of the magnitude of the • 1970 — Uranium enrichment project announced " apparent discrepancy". • 1971 —Approval for R&D based on gun-assembled device relating to nuclear To supplement these activities, an exhaustive explosions for peaceful purposes • 1973 — Investigation into separation of lithium isotopes examination of the performance of the Y-plant • 1974 over its entire operating history was undertaken. — Prime approves limited programme for development of nuclear This examination involved the analysis of data weapons as deterrent from several thousand operating records, which — First stage of pilot enrichment plant commissioned detailed the plant status, on a daily basis, in terms — Approval for test site development in the of availability of separating modules, the feed • 1975 — Work on the Kalahari test shafts commenced • 1976 — Export from the USA of fuel for the SAFARI-1 research reactor stopped. rate and the assay of feed, product, and tail • 1977 streams. Technical documents describing phe- — Kalahari test site abandoned nomena which had affected the plant perform- — Full cascaded operation of the pilot enrichment plant ance were also studied. • 1978 — First HEU product withdrawn from the pilot enrichment plant The results of this examination showed that • 1979 — First nuclear device completed by the AEC the amount of HEU declared to have been pro- — Decision that ARMSCOR should take over programme from the AEC and duced by the Y-plant was consistent with the produce all further devices. plant's production capacity. On the basis of these studies the IAEA deter- mined that it was reasonable to conclude that the • 1980 — Construction of tritium handling laboratory completed uranium-235 balance of the HEU, LEU, and de- • 1981 — ARMSCOR/Circle facilities completed pleted uranium produced by the Y-plant was — Approval of the Gouriqua programme for commercial PWR technology devel- consistent with the natural uranium feed; and that opment, as well as possible future tritium and plutonium production the amounts of HEU that could have been pro- • 1982 — Second device completed duced by the plant were consistent with the • 1985 amounts declared in the initial report. — Government decision to limit number and type of devices to seven gun-assem- bled devices, to further develop implosion technology and to study more advanced The operating records of the Z-plant were concepts subject to detailed scrutiny which enabled the — Lithium-6 Avlis programme redirected towards lithium-7 production for water plant operation to be modelled, on a daily basis, chemistry control in commercial power reactors from its very beginning to the day of the initial • 1987 — Commercial programme for tritium radioluminescent light sources started inventory. A comparison of records showed, for • 1987-1989 — Completion of four additional devices • 1989-1991 — Construction of facilities at ARMSCOR/ central a certain period of plant operation, that the laboratories amount of U-235 transferred to depleted uranium • 1989 — Decision to terminate nuclear weapons programme (November). waste storage as indicated in the operating re- Gouriqua programme stopped. cords was substantially more than that recorded in the accounting records. Further examination of records and measurement of samples of • 1990 — Pilot enrichment plant ceased operation () — by State President for destruction of the six completed nuclear devices and the incomplete seventh device (26 February) • 1991: — Accession to the NPT (10 July) — All HEU returned from ARMSCOR/Circle to the AEC (14 March to 6 September) — Signature and entry into force of the safeguards agreement (16 September); Initial report submitted (30 October) — Start of IAEA ad hoc inspections (November) • 1993 — Destruction of documentation relating to nuclear weapons programme ordered by State President on 17 March; destruction completed on 23 March — State President's announcement to Parliament of the existence and subsequent abandonment of the former nuclear weapons programme (24 March) — Preliminary visit by IAEA team members to the ARMSCOR/Circle facilities (25 March) — Visits of the IAEA team to assess the status of the former nuclear weapons programme (22 April to 4 May. 3-11 June, and 9-13 August).

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stored depleted uranium confirmed that the data (AEC), Pelindaba. They were carrying out fol- recorded in the accounting records were based on low- actions directed towards the clarification inaccurate nominal values and that the data con- of the "apparent discrepancy" in the isotopic tained in the operating records more correctly balance of the HEU material produced by the reflected the actual material transfers. Y-plant. On the day after the declaration, these The consequential corrections to the records two team members made a preliminary visit to a to take account of this finding essentially re- number of key facilities concerned with the solved the "apparent discrepancy" in the pre- abandoned nuclear weapons programme. viously calculated isotopic balance for the Z- Over the following 5-month period, the team, plant. In addition, some other less prominent augmented by nuclear weapons experts, carried errors and omissions were identified in the initial out inspections at a number of facilities and loca- report and their correction contributed to the con- tions that had been declared to have been involved clusion that isotopic balance of the Z-plant was in the former nuclear weapons programme. The satisfactory. objectives of these inspections were to: • gain assurance that all nuclear material used in the nuclear weapons programme had been Ascertaining the status of South Africa's returned to peaceful usage and had been former nuclear weapons programme placed under IAEA safeguards; • assess that all non-nuclear weapons specific The inventory of HEU declared by South components of the devices had been de- Africa in its initial report was substantial. The stroyed; that all laboratory and engineering IAEA recognized that this material could have facilities involved in the programme had been been taken to indicate that a significant compo- fully decommissioned and abandoned or con- nent of the HEU inventory had been recovered verted to commercial non-nuclear usage or from an abandoned nuclear weapons programme peaceful nuclear usage; that all weapons-spe- or, less likely, had been accumulated to supply a cific equipment had been destroyed and that planned nuclear weapons programme which had all other equipment had been converted to been abandoned prior to its implementation. commercial non-nuclear usage or peaceful South Africa had no obligation to declare nuclear usage; what had been the past purpose of this material. • obtain information regarding the dismantling Equally, the primary task of the IAEA was to programme, the destruction of design and ascertain that all nuclear material had been de- information, including draw- clared and placed under safeguards; priority was ings, and the philosophy followed in the de- given to this task during 1992. struction of the nuclear weapons; In addition to the established accountancy • assess the completeness and correctness of the verification measures, the IAEA, acting on infor- information provided by South Africa with mation received from Member States, carried out respect to the timing and scope of the nuclear a number of inspections. They included the tak- weapons programme, and the development, ing of environmental samples, at a location that manufacture,and subsequent dismantling of was later declared to be an unused nuclear weap- the nuclear weapons; ons test facility in the Kalahari desert and at a • consult on the arrangements for, and ulti- number of abandoned buildings (including a mately to witness, actions at the Kalahari test general purpose critical facility) located just out- shafts to render them useless; side the Pelindaba security fence. The South Af- • visit facilities previously involved in or asso- rican officials were very co-operative in facilitat- ciated with the nuclear weapons programme ing access to these locations but claimed lack of and to confirm that they are no longer being detailed knowledge of their past use. used for such purposes; It is now a matter of record that, on 24 March • consult on future strategies for maintaining 1993, President de Klerk, in a speech broadcast assurance that the nuclear weapons capability to the South African Parliament, made a declara- would not be regenerated. tion that "at one stage, South Africa did, indeed, These objectives were based on the IAEA's develop a limited nuclear deterrent capability". rights and obligations under the safeguards President de Klerk's statement included a agreement and on the stated policy of the South description of the scope and objective of the African Government for full transparency with "capability" and the rationale for its abandon- respect to the country's former nuclear weapons ment and South Africa's accession to the NPT. programme. The IAEA team had extensive dis- It is significant to note that on the day of the cussions with the South African authorities and declaration, two members of the IAEA team technical staff at the AEC and at the State-owned were present at the Atomic Energy Corporation armaments corporation (ARMSCOR) which had

46 • IAEA BULLETIN, 1/1995 . NATIONAL REPORTS been responsible for the production phase of the plutonium devices and to limit the production of nuclear weapons programme. Detailed briefings lithium-6; however, it allowed further develop- were provided on the various phases of the pro- ment work on implosion technology and theo- gramme and on the associated development and retical work on more advanced devices. production facilities. Information on the future The first prototype deliverable device had development of the programme, which had been been completed in December 1982, but it was not envisaged before the order to dismantle the nu- until August 1987 that the first qualified produc- clear weapons programme intervened, was also tion model was completed. The delay was provided. largely due to the implementation of a rigorous Information from IAEA Member States was engineering qualification programme directed used to confirm that all relevant facilities/loca- towards safety and security under a range of tions had been inspected. postulated storage, delivery, and accident scenar- On the basis of official documents, pro- ios. When, in November 1989, the decision was gramme records, and information obtained taken by the Government to stop the production through interviews with principal personnel at of nuclear weapons, four further qualified deliv- the various facilities and locations involved in erable gun-assembled devices had been com- the programme, the IAEA team was able to pleted and the HEU core and some non-nuclear document the timing and scope of the nuclear components for a seventh device had been fabri- weapons programme. (See box on page 45 for a cated. On 26 February 1990, the State President chronology of the main events.) issued a written instruction that, inter alia, all In the 10-year period up to 1979, all research existing nuclear devices were to be dismantled and development work on nuclear explosive de- and the nuclear materials were to be melted down vices was done by the South African Atomic and returned to the AEC in preparation for South Energy Board, the forerunner of the AEC. This Africa's accession to the NPT. work resulted in the production of a "non-deliv- By the time of the IAEA team's visit in April erable demonstration device", which was designed 1993, the dismantling and destruction of weap- in such a way that, if the need arose, it could be ons components and the destruction of the tech- rapidly deployed for an underground test to dem- nical documentation had been nearly completed. onstrate South Africa's nuclear weapons capabil- Dismantling records concerning the HEU com- ity. Its purpose remained that of a demonstration ponents of the weapons were available. They device throughout the programme; it was never provided sufficient detail to enable the converted to a deliverable device. ARMSCOR data to be correlated with the corre- It was in 1979 that the responsibility for the sponding data in the nuclear material account- nuclear weapons programme was transferred to ancy records maintained by the AEC. ARMSCOR, while the AEC was made responsi- The dismantling of the non-nuclear compo- ble for the production and supply of HEU and for nents of the weapons had been carried out in theoretical studies and some development work accordance with procedures approved by the in nuclear weapons technology. ARMSCOR's South African authorities. A number of de- principal nuclear weapons activities were carried stroyed or partially destroyed components had out in the so-called Circle facilities, located some been retained and were shown to some members 15 kilometers away from the AEC's estab- of the team in April 1993. Remaining records, in lishment at Pelindaba. The Circle facilities were the form of " build history" logbooks for the com- constructed during 1980 on the basis of designs pleted weapons and the experimental devices, were provided by the AEC and were commissioned in examined and compared with the dismantling May 1981. The nuclear weapons programme listings. Identification numbers of remaining thus established involved: components were compared and found to be con- • the development and production of a number sistent with those shown in the records. of deliverable gun-assembled devices; The team carried out an audit of the records • lithium-6 separation for the production of trit- of the transfer of enriched uranium between the ium for possible future use in boosted de- AEC and ARMSCOR/Circle. As a result of this vices; audit, the team concluded that the enriched ura- • studies of implosion and thermonuclear tech- nium originally supplied to ARMSCOR/Circle nology; had been returned to the AEC and was subject to • research and development for the production IAEA safeguards at the time the safeguards and recovery of plutonium and tritium. agreement entered into force. In September 1985, the South African Gov- The team visited all facilities identified as ernment decided to limit the scope of the pro- having connection with the former nuclear weap- gramme to the production of seven gun-assem- ons programme. It is appropriate to record the bled devices, to stop all work related to possible active co-operation of the South African authori-

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ties in arranging for access to all facilities that the the AEC to the nuclear weapons programme had team requested to visit — both those facilities been returned to the AEC and was subject to which had been provisionally listed by the South IAEA safeguards at the time the safeguards African authorities as having direct connection agreement entered into force. with the former nuclear weapons programme, or The findings from the team's examination of with peripheral activities, and additional facili- records, facilities, and remaining non-nuclear ties identified by the team. The IAEA is not in components of the dismantled/destroyed nuclear possession of any information suggesting the ex- weapons, and from the team's evaluation of the istence of any undeclared facilities connected amount of HEU produced by the pilot enrich- with the programme. ment plant, showed consistency with the de- Actions were taken by ARMSCOR to render clared scope of the nuclear weapons programme. useless the test shafts at the Vastrap (Kalahari) The team found no indication to suggest that site, in accordance with a plan incorporating spe- there remained any sensitive components of the cific suggestions made by the IAEA team. Al- nuclear weapons programme which had not been though the implementation of this plan met with either rendered useless or converted to commer- some initial practical difficulties, the measures to cial non-nuclear applications or peaceful nuclear render the test shafts useless were successfully usage. completed in July 1993 and were witnessed by Also, for the Z-plant, it was possible on the IAEA safeguards inspectors. basis of the team's examination of the opera- The equipment used for uranium metallurgy tional records, sampling, and analyzing of UF6 at ARMSCOR/Circle had been returned to the from certain tail containers and the correction of AEC at the end of the programme. The whole minor other errors in the initial inventory to con- uranium metallurgy process at clude that the amounts of LEU reported as pro- ARMSCOR/Circle had been dismantled and de- duced by the plant was consistent with the docu- contaminated. The machine tools used for manu- mented operation of the plant. facturing the HEU and high explosives compo- These general conclusions had strong technical nents had been decontaminated and are now bases and were significantly supported by the trans- available for commercial non-nuclear applica- parency and openness of the South African authori- tions. The South African authorities stated that ties with respect to access to information and loca- specialized equipment supporting the weapons tions, in particular the stated and demonstrated systems in the form of computerized testing willingness of the authorities to facilitate access to equipment has been rendered useless through the any location that the IAEA may identify. destruction of the specific software. The IAEA's assessment of the completeness of South Africa's inventory of nuclear facilities and materials and its assessment of the status of General conclusions the former nuclear weapons programme — as in all cases where a large nuclear programme Based on the IAEA's extensive verification comes under safeguards — is not free from activities in South Africa, a number of general uncertainty. conclusions have been made. In the case of South Africa, the results of It was determined that the magnitude of the extensive inspection and assessment, and the "apparent discrepancy" in the uranium-235 bal- transparency and openness shown, have led to ance associated with the Y-plant was such that — the conclusion that there were no indications to having regard to the normal uncertainties ex- suggest that the initial inventory is incomplete or pected to be involved in the plant historical oper- that the programme was not ating and accounting records — it was reason- completely terminated and dismantled. How- able to conclude that the uranium-235 balance of ever, in the future, and without prejudice to the the HEU, LEU, and depleted uranium produced IAEA's rights under the safeguards agreement, by the pilot enrichment plant was consistent with the IAEA plans to take up the standing invitation the uranium feed. Assessment of the production of the South African Government — under its capacity of the pilot enrichment plant, on the reiterated policy of transparency — to provide basis of operating records and supporting techni- the IAEA with full access to any location or cal data provided to the IAEA team by the AEC, facility associated with the former nuclear weap- indicated that it was reasonable to conclude that ons programme and to grant access, on a case- the amounts of HEU which could have been by-case basis, to other locations or facilities that produced by the plant were consistent with the the IAEA may specifically wish to visit. • amounts declared in the initial report. The IAEA team's audit of the associated re- cords indicated that all of the HEU provided by

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