Fuzzy Evaluation of Horizontal Nuclear Proliferation Risk for More Efficient Resource Allocation of IAEA's Integrated Safeguards

This paper proposes a fuzzy method of evaluating horizontal nuclear proliferation risk for more efficient use of the International Atomic Energy Agency's (IAEA's) integrated safeguards (IS). The nuclear proliferation risk R_j of nation j is defined as (1 - _j) × (1 - _j), where _j is the probability of nation j maintaining only peaceful nuclear activities for at least 1 yr, is the probability that the IAEA's IS detect indicators of nuclear explosive device (NED) acquisition activities, and _j is the probability that the international community will force nation j to abandon these activities after the indications are detected.

Because _j is equal to and replaces the concept of nuclear nonproliferation credibility used in previous studies, this paper uses a method of deriving this credibility and converting it into _j, which is evaluated using trapezoidal fuzzy numbers. Case studies of four nations currently under the IS reveal that the probability of IS detection of indicators of NED activity can be reduced by several tens of percent for some countries without exceeding the upper limit of horizontal nuclear proliferation risk that the international community had accepted in the past.

Therefore, depending on the value of nuclear proliferation risk determined using the fuzzy method, the IAEA will be able to use its limited resources efficiently by reducing unnecessary expenditures for some nations under the IS and reallocating those resources to inspections of other nations without increasing the risk of proliferation.