FEATURES

Safeguards at research reactors: Current practices, future directions

Some new verification measures are being introduced to improve the efficiency and the effectiveness of the Agency's safeguards

by Giancarlo /approximately 180 research reactors and crit- immersed in a large pool of water that provides Zuccaro-Labellarte ical assemblies currently are under IAEA safe- both cooling and moderation. The fuel and guards. The vast majority of the research reac- assemblies in the core of a swimming pool reac- Robert Fagerholm tors operate at relatively low power levels (10 tor are normally visible and accessible for safe- megawatts-thermal or lower) and the critical guards measurements. assemblies at virtually zero power.* From a Other types of research reactors operate at safeguards standpoint, this is important since a higher power levels (exceeding 10 megawatts- reactor's power level is a determining factor of thermal). They need more powerful heat its capability to produce plutonium. Along with removal systems and are therefore normally high-enriched (HEU) and uranium- enclosed in core vessels and equipped with 233, plutonium is considered a "direct use" coolant pumps and heat exchangers. The fuel material which could be diverted for the pro- elements in the reactor core at these installa- duction of nuclear weapons. tions are usually not visible or accessible for In this article, the IAEA's safeguards safeguards measurements. implementation at research reactors is Research reactors are widely used for scien- addressed, including aspects related to diver- tific investigations and various applications. sion and clandestine production scenarios and produced by research reactors provide main verification activities. Additionally a powerful tool for studying matter on nuclear, addressed are new safeguards measures that atomic, and molecular levels. Neutrons often are being introduced for purposes of providing are used as probes by nuclear and solid state assurances about the absence of undeclared physicists, chemists, and biologists. Neutron nuclear materials and activities. experiments can also be performed outside the biological shield by means of installed beam tubes. Additionally, specimens can be posi- Safeguarding research reactors tioned in or near cores for neu- tron irradiation, e.g. to produce radioactive iso- Several types of research reactors are in topes for medical or research use. operation. A very common type of research reac- Diversion scenarios. Under existing com- tor is the swimming pool reactor which typical- prehensive safeguards agreements, the IAEA ly operates at power levels around or below 10 has the right and obligation to verify that no megawatts-thermal. The fuel elements normally nuclear material is diverted from peaceful use consist of HEU (enriched to contain 20% or to nuclear weapons or other nuclear explosive more of the isotope uranium-235) or low- (LEU, containing less than 20% uranium-235) contained in aluminum alloy *A critical assembly is a research tool consisting of a con- plates, rods, or tubes. The reactor core is figuration of nuclear material which, by means of appro- priate controls, can sustain a chain reaction. As distinct from a research or power reactor, it normally has no spe- cial provision for cooling, is not shielded for high-power Mr. Zuccaro-Labellarte is Section Head of Procedures, operation, has a core designed for great flexibility of Division of Operations (C) and Mr. Fagerholm is a safe- arrangement, and uses fuel in a readily accessible form guards analyst in the Division of Concepts and Planning of which is frequently repositioned and varied to investigate the IAEA Department of Safeguards. various reactor concepts.

20 IAEA BULLETIN, 4/1996 FEATURES devices. States conclude these agreements elements by fertile material targets. However, with the IAEA pursuant to their obligations studies have shown that it is not possible to pro- under the Treaty on the Non-Proliferation of duce one SQ of plutonium in one year at a Nuclear Weapons (NPT). research reactor that operates below about 25 For research reactors, the following diver- megawatts-thermal. The actual production sion scenarios are considered: capability depends on the individual reactor Diversion of fresh or slightly irradiated design and operating parameters. fuel for clandestine chemical extraction of fis- The Agency's current safeguards system sile material. This scenario — for which com- requires that all research reactors operating at monly available chemical engineering equip- power levels above 25 megawatts-thermal are ment would be adequate — is given particular evaluated with respect to their capability to pro- safeguards attention at facilities where the fresh duce at least one SQ of plutonium (or uranium- fuel contains HEU or plutonium, for which no 233) per year. further transmutation or enrichment would be At present, there are about 30 thermal needed for use in a nuclear explosive device. research reactors with power levels of 10 About 20 research reactors under IAEA safe- megawatts-thermal or higher which are subject guards are currently using such direct-use fissile to IAEA safeguards. About 10 of these operate material in amounts equal to more than one sig- at power levels exceeding 25 megawatts-ther- nificant quantity (SQ). For safeguards purposes, mal and are subject to additional safeguards one SQ is currently defined as 8 kilograms plu- measures with respect to the clandestine pro- tonium or uranium-233 or 25 kilograms of ura- duction scenarios. nium-235 in HEU. International efforts — for example, under the US Reduced Enrichment Research and Test Elements of "classical" IAEA safeguards Reactor programme — have been directed at developing the technology needed to use LEU Currently, the IAEA's principal inspection instead of HEU fuel in research and test reactors activities at research reactors are an annual without significant degradation in their perfor- physical inventory verification (PIV); inspec- mance for experiments, costs, or safety aspects. tions serving timely detection purposes for Diversion of spent or extensively irradiated fresh (unirradiated) fuel, core fuel, and spent fuel for clandestine chemical extraction of fis- fuel; auditing of records and reports; verifica- sile material in a reprocessing facility. This tion of specific types of fuel transfers; and veri- scenario is technically more demanding and fication activities to confirm the absence of time-consuming than the one mentioned above clandestine irradiation of fertile material. because of the high level of radioactivity from the fuel which is involved. However, it is of par- A research reactor in ticular concern at about 15 research reactors Japan is used for tests under IAEA safeguards due to large accumulat- of fuel behaviour as part of nuclear safety ed quantities of spent fuel, and it is of impor- Studies. (Credit: JAERI) tance at more than 10 others. Clandestine production scenarios. The possibility exists for clandestine production of plutonium or uranium-233 through irradiation of undeclared fertile material. As techniques for using neutrons have developed, there has been an accompanying need for higher levels of neu- tron flux in order to carry out more complex and time-consuming experiments in a shorter time. Large research reactors have been constructed to provide these flux levels. At such reactors, production of substantial quantities of plutoni- um or uranium-233 through irradiation of unde- clared fertile material would be technically fea- sible. This could be achieved, for example, by placing target materials in irradiation positions in or near the core, or by replacing reflector

IAEA BULLETIN, 4/1996 21 FEATURES

• analysis of the facility design and operations; • containment and surveillance (C/S), among other measures (e.g. power monitoring), which confirm that the reactor is shut down or has not operated for a sufficient period; • performance of one of the following activi- ties: 1) the use of C/S measures to confirm that no unrecorded introduction of fertile materials or their removal after irradiation has taken place; or 2) evaluation of the fresh fuel consumption and the operator's data on spent fuel burnup to con- firm that they are in conformance with declared design information and reactor operations. Information of relevance to safeguards about the design of the research reactor is pro- vided to the Agency by the State. It is examined The research reactor at At the PIV, the fresh fuel and spent fuel are and verified according to established Agency Bataan in Indonesia. (Credit: Meyer/IAEA) verified using non-destructive assay (NDA) procedures and is re-examined at least once a methods to confirm that all declared fuel is year. When modifications or changes in design accounted for. Core fuel is verified by NDA information relevant to safeguards occur, they methods or by a criticality check corroborated are verified to establish the basis for adjustment by other reactor data.* Interim inspections are of safeguards procedures, and the necessary performed at research reactors at intervals adjustments are then implemented. determined by the safeguards timeliness requirements for specific inventories of differ- ent material types.** If more than one SQ is Elements of strengthened safeguards present at a facility, verifications of the core fuel at research reactors and spent fuel are carried out four times per cal- endar year at quarterly intervals, while verifica- In June 1995, the IAEA Board of Governors tion of fresh fuel containing HEU and plutoni- endorsed the general direction for a strength- um are carried out 12 times per calendar year at ened and cost-effective safeguards system, monthly intervals. Verifications of fresh fuel under Part 1 of what is known as "Programme containing less than one SQ of HEU or plutoni- 93+2". Part 1 measures are those that can be um are carried out four times per calendar year implemented under the Agency's existing legal at quarterly intervals if more than one SQ of authority provided in comprehensive safeguards HEU or plutonium (fresh and irradiated) is pre- agreements. sent at the facility. Some measures designed to increase the effi- Transfers of fuel and experimental material ciency and improve the effectiveness of safe- containing HEU, plutonium, or uranium-233 guards are of a general nature. They include into or out of a facility are verified either at the early provision of design information; and shipping or receiving facility if shipments are description of the State's nuclear fuel cycle. sealed by the Agency, or at both the shipping Other measures are more specific to particu- and receiving facilities if the shipment is not lar facilities. They include the description and sealed. status of the research and development activities, To check that there has been no unrecorded in particular related to uranium enrichment and production at high-power research reactors reprocessing; environmental sampling at strate- (greater than 25 megawatts-thermal) of one SQ gic points selected for routine inspections; unan- of plutonium or uranium-233, one of the fol- nounced routine inspections to confirm declared lowing procedures are used: nuclear activities and the absence of undeclared nuclear activities; unattended monitoring and remote transmission of safeguards information. *A criticality check is an inspection activity which provides evidence that a reactor has reached criticality and that a The continuous development of new tech- controlled nuclear reaction is sustained, i.e. the core con- nologies also brings to light the possibility of new tains at least minimal critical amounts of nuclear material. safeguards measurements and surveillance sys- "Safeguards timeliness is related to the time needed to convert the nuclear material from its present status to HEU tems, which allow the remote operation of equip- or plutonium metal. ment and remote transmission of safeguards data.

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The impact of these new measures on the opera- clared operations. In other research facilities tors and States will depend very much on the type where the quantities of declared nuclear mater- of nuclear facilities and the particular States or ial are below one SQ, the frequency of inspec- areas where these facilities are located. tions is normally once per year, or for some An essential component in introducing the larger research reactors, two inspections per proposed measures is the increased co-operation year. In these cases the new measures can con- with the States and the State System of siderably contribute to improving the Agency's Accounting and Control (SSAC) for nuclear capability to provide assurance regarding the material. This is needed to enable the IAEA to absence of undeclared activities. plan and conduct inspection activities more effi- Measures which are presently being intro- ciently. The SSACs and IAEA may also carry duced under the IAEA's existing legal authority out inspections or selected support activities include: jointly in order to economize resources and to Environmental sampling. The irradiation of make optimal use of the present system.The co- targets and their subsequent dissolution in a hot ordinated and efficient use of the new measures cell to extract, for example, plutonium might be will reduce the current effort of safeguarding successfully concealed from the classical safe- declared nuclear material and at the same time guards measures, particularly if the quantities pro- will enhance detection capability of possible duced are much less than one SQ. Where the undeclared nuclear activities and material. inspections are announced and the frequency is As mentioned earlier, the frequency of inspec- limited to once per year, it might be possible to tions at research reactors varies from one to 12 conceal the undeclared activity and interrupt it per year, depending on the type and quantity of before the IAEA inspection is carried out. nuclear material present at the facility. The cur- However, in any chemical process used to separate rent inspection activities are planned in such a fissile material, small amounts of material would way as to provide assurance that the declared migrate to the surroundings of the area where this nuclear material remains under safeguards. It is material is processed. Even though great care were more difficult within the present system to give taken to prevent losses, traces of this activity could assurance that the reactor has not been used to remain and could be detected by the sophisticated produce undeclared plutonium or uranium-233 and highly sensitive analytical methods used on by undeclared operations, in particular if the pro- environmental swipe samples. duced quantity of undeclared fissile material is The impact which these analytical tech- much less than one SQ (e.g. 2 kg or less of pluto- niques will have on facility operations is low, nium per year). since the sampling is carried out by taking For facilities now inspected 12 times per swipe samples inside or outside hot cells during year, measures can be taken during these fre- regular inspections; little preparation is required quent inspections to check for possible unde- by the operator.

Overview of safe- guards measures Detection Capability and detection 1Declared nuclear material Undeclared nuclear material/activities capabilities at research reactors Determination of Determination ol Quantity Timeliness Quantity Operation/Production

Present safeguards measures Yes Yes No Yes*

Environmental sampling No No No Yes** Unannounced inspections Yes Yes No Yes Remote monitoring: video surveillance No No No Yes transmission of accountancy data Yes*** Yes*** No No NDA, radiation monitors Yes*** Yes*** No Yes

*The present safeguards system is based on detecting undeclared operations to produce one SQ/year (or more) of undeclared plutonium or uranium-233. "Environmental sampling is effective also in cases of production of much less than one SQ /year. ***ln connection with unannounced inspection arrangements

IAEA BULLETIN, 4/1996 23 FEATURES

Unannounced inspections. Unannounced activities have taken place, particularly when inspections are those where the State and the used in connection with unannounced inspec- operator are first informed of the Agency's tions. The extent to which the necessary equip- intention to carry out an inspection at the time ment can be used in a facility depends on the when the IAEA inspector arrives at the entrance facility conditions and operating practices and of the site. The State's co-operation is necessary requires the co-operation of the State, the since the implementation of such inspections SSAC, and the facility operator, who will be requires that the State grant multiple-entry visas operating the equipment that provides the data or allow entry without visas to the inspectors. In for use by the IAEA. addition, arrangements have to be made by the The utilization of remote monitoring will operator to grant access to the Agency inspector enable a reduction in the requirement for to the facility in a short time. The facility oper- inspectors to be physically present, with addi- ator needs to be prepared for an unannounced tional reductions in intrusiveness in facility inspection at any time. The benefit is that an operations. (See table on previous page for a assurance about the absence of undeclared general overview of the verification capabilities activities at the facility at the time of the inspec- provided using new safeguards measures at tion implies that this has been the case with cer- research reactors.) tain probability over the whole time interval since the last on-site inspection. Remote monitoring. These types of systems Future co-operative efforts include: Video surveillance. The installation of cam- Over the past years, the IAEA and its eras which can be operated remotely would allow Member States have been taking steps to continuous surveillance of facility operations and strengthen the effectiveness and improve the reduce the possibility that undeclared activities efficiency of the safeguards system. The objec- could be carried out undetected. This technique tive is to provide assurances that a State's is not intrusive to the operator, since the only declared nuclear material remains in peaceful requirement is continuous and sufficient illumi- use and that no undeclared nuclear activities IAEA Member States have endorsed some nation of the area under surveillance. and material are known to exist. new safeguards Measurement and accountancy data. The "classical" safeguards system based on measures and are considering others. Remote transmission of inspection data would the accountancy of nuclear material has proved (Credit: Pavlicek/IAEA) provide additional assurance that no undeclared to be reliable in providing assurances about the peaceful use of declared material and declared facilities and installations. However, the system needs to be further strengthened with respect to providing assurances about undeclared nuclear materials and activities. Some of the new safeguards measures that have already been approved are aimed to strengthen the system and have to some extent already been introduced. They considerably improve the capability of detecting the diver- sion of declared nuclear material and the pro- duction of undeclared nuclear material. However, they are not capable of determining the quantity of undeclared nuclear material pro- duced through undeclared activities. Attaining such verification objectives would require greater co-operative efforts and additional safe- guards measures. At the present time, the IAEA Board of Governors is considering further measures for strengthening the effectiveness and efficiency of safeguards. The extent to which additional mea- sures can be implemented will depend upon the outcome of its work. d

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