A Methodology For Safeguards Evaluation And Its Application To Mixed Oxide Fuel Fabrication

This study focuses on the development of a methodology to evaluate safeguardability of various processes in the nuclear fuel cycle. National and international implementation of safeguards systems has been investigated. It was concluded that proliferation is purely a political question that, hopefully, can be prevented by international norms and diplomacy; it does not depend on technical differences between the different processes. On the other hand, the prevention of diversion does depend on technical barriers implemented in nuclear facilities. Therefore, different processes with different technical fixes might have varying degrees of resistivity against diversion. Safeguardability of a process can not be evaluated in absolute terms; rather it can be compared with and ranked against another process. In addition, processes by themselves can not be compared; only plants embodying processes can be compared. This is because processes are not safeguardable but plants incorporating them are. A methodology was developed which compares and ranks various processes in the nuclear fuel cycle. It estimates the weights of different safeguard characteristics of a nuclear facility and calculates a dimensionless number --safeguards index-- for each process under evaluation. By comparing these safeguards indices, one is able to rank processes against each other. As a case study, comparison of two fast reactor fuel fabrication processes, pelletization and spherepac, were selected. At present, no fast reactor fuel fabrication facility exists on a commercial scale. Hence, two fuel fabrication facilities, each incorporating one process, were designed, in enough detail to make the safeguards comparison possible. Safeguards indices were calculated for these two plants based on the information derived from their designs. The result revealed that the spherepac process is higher in rank relative to the pellet process; the spherepac process is simpler to safeguard relative to the pellet process. Derivation of some of the data used in calculation of safeguards indices was based partly upon subjective judgment. A sensitivity analysis was conducted to test the dependency of the result on subjective judgment. It was concluded that as long as the probability estimation and numerical value assignments remain in a reasonable range, the method is relatively insensitive to subjective judgment.