Study on Effectiveness Assessment of Proliferation Resistance

摘要

It is regarded as one of key issues for non-proliferation in future nuclear fuel cycle to incorporate Proliferation Resistance (PR) into its early design stages. The Nuclear Nonproliferation Study Committee of the University of Tokyo has been studying the substance and implication of PR from the viewpoints of risk evaluation on nuclear proliferation. As an example study, ten next-generation reprocessing technology candidates were evaluated with GIF PR & PP methodology to find degree of relative difference in PR from the presently available technology, i.e, PUREX. All the 10 technologies represent significant difference in Technical Difficulty (TD) and Material Type (MT), where decontamination factor (purity of plutonium product) and its related processes play predominant PR role. Higher in the level of Safeguards is implemented, stronger in entire PR effect is observed. This is due to increase in not only Detection Probability, but also Proliferation Time. The effect of MT and TD plays more remarkably in the cases of break-out, namely those new technologies may be able to help delay in acquisition of weapon. However, the response time to prevent proliferation by the international society may not be short enough in general. The extrinsic measure, in particular, Safeguards plays more remarkable and essential PR role to make the process transparent for a State, that deters proliferation and arouses little intention of weponization. TD and MT should work rather deterring the breakout than stopping weapon acquisition, although it may help to delay the acquisition in some degree. Hence, it can be said that intrinsic measures such as TD and MT complement with extrinsic measure. The effect of TD and MT, however, may not be able to be powerful enough to prevent nuclear proliferation by themselves. PR effectiveness in proliferation risk was assessed in this study. It was found that the effectiveness of PR measures is subject to the status of each nation, although those, in general, are of some benefit in preventing nuclear proliferation. Uniform application of the PR measures to the multiple nations, therefore, may not be reasonably effective and efficient.