Quantifying relative proliferation risks from nuclear fuel cycles

Commercial nuclear fuel cycles inevitably include stages where nuclear materials can be diverted to the manufacture of nuclear weapons. The risk of such diversion is usually of a political or military origin. However, the laws of nature favour some stages or routes and exclude others depending on the available level of technology. This paper will discuss technical aspects of assessing the risks of nuclear weapons proliferation arising from a peaceful nuclear programme. Some countries, notably the United States, dramatically revised their nuclear fuel cycle policies during the latter part of the 1970s. The changes were, at that time, largely regarded as being due to the nonproliferation incentives. Therefore, much attention was paid to analysing the proliferation contribution 1-3. Although the assessments have been mostly qualitative a variety of quantitative or semiquantitative methods have been presented as well. It is the intention in this paper to review the status of these quantitative approaches. For the purposes of this paper, proliferation is defined to mean development of the material and technical resources required for production of nuclear explosives in countries which now do not have such capability. As long as there are no principal changes in the world situation the risks related to nuclear weapons proliferation deserve continued attention. In fact, one could assert that technically speaking the risk has been constantly increasing with the accumulation and spread of technological knowledge. The introduction of some new technologies, such as laser enrichment, also enhance the risk. Strictly speaking the acquisition of weapons-grade material is only one step in the production of explosives. Assembling the weapon requires additional technological skills. A civilian nuclear power programme may make it easier to develop these skills but the contribution is likely to be very marginal. Therefore this article deals almost exclusively with the first step covering the material acquisition. In this sense the meaning of proliferation becomes identical to that of diversion. The International Nuclear Fuel Cycle Evaluation (INFCE) was a major international study assessing the risk of weapons proliferation from nuclear fuel cycles. Since its completion in 1980 there have been noticeable changes in the outlook for nuclear energy. Much greater security now seems to exist for the uranium supply as well as the availability of enrichment services, at least if one compares supply and demand on a global basis. In addition to the enhanced supply potential, this is caused by the cancellations of some power plants and the overall reduction in the projections of future nuclear capacity. Again on a global scale, there is less urgency for large scale uses of plutonium in fast reactors. Consequently, less economic incentives exist for embarking on a new civilian development programme of either enrichment or reprocessing. On the other hand, elaborate plans have been made in some countries to dispose of spent fuel as a waste. These developments may have implications also for non-proliferation purposes.