« iepriekšējāTurpināt »
measurement and accountability technology, materials control, and physical security including effective use of containment and surveillance techniques.
A major component of effective technology transfer is education and training in the use of modern NDA instrumentation and information-handling and analysis systems. The entire area of safeguards professional training has received marked impetus from the Three Mile Island nuclear reactor accident and the resultant three main "lessons learned": the need for (1) better professional training of reactor operators, (2) better measurement instrumentation, and (3) better emergency response. One notable example of the effective transfer of modern safeguards technology to plant operators and safeguards inspectors alike is DOE's ongoing Safeguards Technology Training Program conducted by LASL through four separate course offerings per year:
1. Fundamentals of Nondestructive Assay of Fissionable Material Using Portable Instrumentation.
2. In-Plant Nondestructive Assay Instrumentation (to be succeeded in 1981 by a course on advanced instrumentation based on neutron detection methods).
3. Gamma-Ray Spectroscopy for Nuclear Materials Accountability. 4. Advanced Systems for Nuclear Materials Accounting.
These training courses attract well over 100 participants annually. Participants from the United States represent both the government and private sectors and those from the IAEA inspectorate represent a large number of countries around the world.
Technology transfer and assistance to the IAEA encompasses not only development, test, and evaluation of instruments, but also personnel training (of highest priority to IAEA), technical con
sultation, and direct assistance to the IAEA safeguards staff by visiting consultants and resident experts on loan from member states. Two examples are US participation in the IAEA International Working Group on Reprocessing Plant Safeguards and in the IAEA Advisory Group on Fuel Element Fabrication. Both groups are concerned with the application of IAEA safeguards to the advanced large-scale fuel-cycle facilities that are foreseen for the future. Four LASL safeguards staffers are currently assigned to the IAEA Department of Safeguards at Agency headquarters in Vienna.
A new component in the safeguards. technology transfer program at LASL is the International Training Course on Nuclear Materials Accountability sponsored by DOE in cooperation with IAEA. This course, authorized by the US Nuclear Non Proliferation Act, was conducted May 27-June 6, 1980, at Bishop's Lodge near Santa Fe, New Mexico. The course provided to foreign governmental and institutional managers the basic knowledge needed to develop national safeguards regulations and requirements for their individual countries, and to plan toward implementation of domestic safeguards systems that will serve national needs as well as those of the IAEA International Safeguards System of inspection and verification. Lecturers for the course were experts drawn from the IAEA, United States, Canada, Czechoslovakia, Germany, and Japan. Delegates from over 25 countries participated in the course. A similar DOE/IAEA sponsored course on the physical protection of nuclear materials. is conducted by Sandia Laboratories each fall.
Emerging Impact and Role of International Safeguards
Recent expansion of the US safeguards program in areas of technical
support for the IAEA and cooperative agreements with other countries reflect the growing importance of international safeguards. IAEA needs can be grouped into two major categories: (1) present requirements for portable measurement instrumentation, inspection and verification capability in direct field inspection applications (for example, the HLNCC instrument shown in Fig. 4) and (2) future requirements for methods, instruments, and techniques to be developed for independent verification of different types of advanced in-plant material accountability and control systems, such as DYMAC.
A major international effort is the TASTEX program, in which the United States, Japan. and IAEA are participating jointly in the development. test, and evaluation of advanced instrumentation and safeguards techniques at the Tokai spent-fuel reprocessing plant in Tokai Mura, Japan. In this program, a K-edge densitometer is used for nondestructive assay of plutonium nitrate product solution. The densitometer, which measures elemental (total plutonium) concentrations in solutions, provides a valuable complement to gamma-ray spectrometry, which measures plutonium isotopic composition. Successful in-plant experience with this type of new NDA instrumentation is expected to lead to the deployment of a wide range of automated NDA instruments at nuclear processing facilities. This should, in turn, provide a sound technical basis for future implementation of near-real-time material measurement and accountability systems in various types of plants and facilities throughout the nuclear fuel cycle.
As regards the outlook for the future. it is significant that this first year of the 1980s will see a number of important developments in international safeguards and nonproliferation. In March, INFCE endorsed stringently safeguarded plutonium based nuclear energy systems
for the future, including the judicious deployment of plutonium breeder reactors (again under strict safeguards and controls) as the only means of avoiding future shortages of uranium fuel. Today the total plutonium inventory of irradiated civilian reactor fuels is easily the order of 100 metric tons and is increasing at a rate of 25-30 tons per year. Although breeder reactors eventually will reduce this inventory. concerns about such potentially large stockpiles of plutonium-in whatever form-have given rise to several international studies
Fig. 4. The high-level neutron coincidence counter (HLNCC) detects neutrons from the spontaneous fission of 240 Pu using 'He proportional counters in a polyethylene moderator. A shift register coincidence technique is used to distinguish fission neutrons from background. The instrument is portable for use by IAEA inspectors. The electronics to operate the detectors and analyze the coincidence data are contained in the package on the table, next to a programmable calculator that is interfaced to the shift register unit.
and evaluations, involving both technical improvements and institutional arrangements, designed to place sensitive materials and fuel-cycle facilities under multinational or international control.
Proposed institutional arrangements include (1) regional fuel-cycle centers, in which large fuel reprocessing and fabrication plants would be co-located to provide economy of size and operational efficiency and to minimize vulnerability to theft and diversion; (2) an international fuel authority responsible for providing fuel service and allocating fuel resources; (3) establishment of international plutonium storage centers under IAEA control (foreseen in the Agency's Statute, Article XII, A.5); and (4) the concept of regional nuclear waste repositories, fuel reprocessing plants, and enrichment facilities under international or multinational authority. Working out the details of any such international or multinational arrangements would be a monumental task indeed, and could only be done by the potential participants themselves. With such proposals, some of them strikingly similar to the international ownership/custody/management concepts in the original Baruch plan, we have, in some sense, come almost full circle in the evolution of international safeguards.
Also in this pivotal year, 1980, two important international safeguards agreements are pending ratification by the US Senate. The first is the USAustralian Agreement on the Peaceful Uses of Nuclear Energy, the first renegotiated safeguards agreement under the new, more stringent safeguards provisions of the NNPA. The second is the US-IAEA Agreement for the Application of IAEA Safeguards in the United States, pursuant to the US 1967 offer to implement IAEA safeguards in all US facilities except those having direct national security significance. A similar voluntary agreement, already in force. with the United Kingdom, is enabling the
IAEA to gain valuable experience in the inspection of a fast-breeder plant and related reprocessing facility. President Carter recently asked the US Senate to take up the US-IAEA Agreement this spring so that ratification can be completed before the (potentially contentious) NPT 5-year review conference of the 116 NPT signatory nations at Geneva in August of this year. The USIAEA Agreement, an act of good faith on the part of the United States, may help to alleviate a certain hardening of position by some countries against the NPT, which some nations view as an unequal treaty that discriminates in favor of the nuclear-weapons states and thereby against all others.
To make the NPT as equitable and acceptable as possible, the IAEA is working hard to upgrade and standardize the applications of NPT "fullscope" safeguards. Measurement and surveillance techniques used by IAEA inspectors are being improved continually both by the IAEA staff and through technical support programs of the United States and other IAEA member nations. Also, through IAEA fieldinspection experience, better methods of inspection, inventory verification, reporting, and assessment are being evolved constantly to maximize inspection efficiency and effectiveness while minimizing intrusion into plant operations and production. Implementation of the US offer to place its peaceful facilities under IAEA safeguards should do much to facilitate further improvement of the IAEA system.
Another key aspect of NPT acceptability and workability is the assurance of an available supply of nuclear fuel-at present, uranium. Irrevocable fuel supply assurances are essential to the fundamental quid pro quo of the NPT agreement and should be extended promptly to nations that meet their nonproliferation undertakings. Uncertainties and doubts about supply assurances in
recent years have had serious repercussions throughout the world nuclear community. An oft-quoted international safeguards slogan succintly states the basic quid pro quo of the NPT Treaty: "Irrevocable safeguards for irrevocable supply."
As many have pointed out (especially to safeguards technologists!), there is no question that safeguards and nonproliferation issues are first and foremost a political problem. However, it is also clear that safeguards technology development, coupled with "real world" operational experience, is indispensable in (1) providing the technical understanding and input essential to prudent planning and decision making, even at the highest political levels, and (2) providing the demonstrated technical means to implement the hardware and systems called for in those plans and decisions. Within severe budget limitations, the IAEA is making every effort to anticipate and prepare for the sophisticated fuel cycles of the future and the commensurately sophisticated technical capabilities that will be needed. to carry out its essential inspection and verification functions effectively.
In concluding, I can do no better than to cite a poignant and timely question posed in a recent National Academy of Sciences report:
Which represents the greater threat to peace? The dangers of proliferation associated with the replacement of fossil resources by nuclear energy, or the exacerbation of international competition for fossil fuels that could occur in the absence of an adequate worldwide nuclearpower program.
Many hope, as I do, that this first year of the new decade will prove to be a milestone of significant progress toward worldwide implementation of effective, workable, and acceptable nuclear safeguards as an indispensable, vital contribution to safe, and safeguarded,nuclear energy for the benefit of mankind.
1. Committee on Nuclear and Alternative Energy Systems of the National Academy of Sciences, Energy in Transition, (W. H. Freeman, San Francisco, 1980).
2. Bertrand Goldschmidt, Le Complexe Atomique, (Fayard, Paris, 1980), now being translated into English.
3. "International Nuclear Fuel Cycle Evaluation." International Atomic Energy Agency, Vienna. February 1980.
4. G. Robert Keepin. "Safeguards Implementation in the Nuclear Fuel Cycle," J. Instit. Nucl. Mat. Mgmt. VII, 3 (1978).
5. USDOE IAEA International Training Course on Nuclear Materials Safeguards (Lecture Text and Video Library) held in Santa Fe, New Mexico, May 27 June 6, 1980.
G. Robert Keepin joined the LASL staff (Critical Assemblies Group) in 1952 after being an Atomic Energy Commission Postdoctoral Fellow at the University of California, Berkeley, and a Consultant to Argonne National Laboratory and to LASL. He was a US Delegate to the First United Nations Atoms for Peace Conference in Geneva in 1955, and IAEA Technical Advisor to the Third Geneva Conference in 1964.
From 1963 to 1965 Keepin was with the Headquarters Staff of the International Atomic Energy Agency in Vienna. Following his return to the United States in 1965, he established the Nuclear Safeguards research and development program at LASL. In 1973 he received a Special Award for Nuclear Materials Safeguards Technology from the American Nuclear Society for his early recognition of the need for NDA instrumentation, his demonstration of practical passive and active assay methods, and his leadership in implementing these techniques and gaining wide acceptance for their use. He is now Program Manager at LASL for Nuclear Safeguards affairs.
Keepin is a Fellow of the American Physical Society and the American Nuclear Society and is National Chairman of the Institute of Nuclear Materials Management. He is widely published in the fields of nuclear and fission physics, reactor kinetics and control, and nuclear safeguards technology, and is an internationally recognized authority in the field of nuclear safeguards and nondestructive assay technology.
Do these residues sent from Rockwell-Hanford at Richland, Washington contain salvagable plutonium? Members of LASL's Plutonium Facility determine the kinds and amounts of special nuclear materials in such heterogeneous waste with nondestructive assay techniques (the segmented gamma scanner and the thermal neutron coincidence counter). Measurements of this sample indicated that the contents were not worth recovering.
Nondestructive Assay for Nuclear Safeguards
by Roddy B. Walton and Howard O. Menlove
Sophisticated nondestructive assay techniques have
nuclear materials reveal their presence by the radiation they produce spontaneously or otherwise. These characteristic signatures form the basis for nondestructive assay (NDA) of sensitive nuclear materials and for modern safeguards measurement technology. NDA techniques are used now by the nuclear industry, defense facilities, and safeguards inspectors to make rapid, accurate measurements of sensitive nuclear materials in diverse forms and compositions and thus to close many gaps in inventory measurements. However, this technology has not drastically changed the overall materials accounting practices of most nuclear facilities. Instead, the nuclear industry has placed heavy emphasis on physical protection to safeguard nuclear materials against overt threats of diversion. Further, a major part of the National Safeguards Program is devoted to increasing these
physical protection measures.
The Los Alamos Scientific Laboratory (LASL) program, on the other hand, has pioneered the development of NDA technology needed not only for inventory closure but also for near-real-time measurement and accountability systems. NDA techniques can be used to assure that no sensitive nuclear materials (SNM) are being lost or diverted from their defined flows and containments. Rapid measurements of SNM in feed materials, process lines, finished products, scrap and waste, and holdup in the plant are all possible with NDA techniques. When put together in an integrated materials control and accountability system, they can deter protracted diversion of SNM by knowledgeable insider by detecting the amount and location of losses in a timely fashion. Such systems can also determine the validity of threats that significant amounts of nuclear material have
been diverted for unauthorized purposes.
At present several NDA-based nearreal-time materials accounting systems are in existence and we are helping to plan such systems for future high throughput fuel production and spentfuel reprocessing facilities. We also continue to work closely with members of the nuclear industry and safeguards inspectors to solve individual measurement problems associated with accurate inventory measurements, quality assurance of nuclear fuel production. and adequate safeguards inspection procedures. For many existing facilities. accounting systems that combine conventional chemical analysis with NDA techniques can provide adequate safeguards, but advanced facilities will require upgraded approaches.
Uranium and plutonium are the principal raw materials of fission weapons and hence the most sensitive nuclear materials to safeguard and to measure.