An integrated methodology for quantitative assessment of proliferation resistance of advanced nuclear systems using probabilistic methods

Abstract

Proliferation is the results of a competition between the proliferating country (proliferation) and the party to resist the proliferation efforts (safeguarder). An integrated evaluation methodology to evaluate proliferation resistance of nuclear energy systems is outlined and demonstrated focusing upon the proliferation competition. The methodology consists of four steps: actor characterization, proliferation competition model development, model input evaluation, and pathway assessment. A success tree method is used to structure the proliferation. The method permits integration of all aspects of proliferation resistance of a nuclear energy system, both intrinsic and extrinsic, in evaluating an integrated proliferation probability measure. Most of the input data obtained in a subjective form are viewed as the current state of knowledge of an evaluator for a system, reflecting an evaluator's beliefs. A modular pebble bed reactor (MPBR) design was chosen as the reference system for demonstration of the methodology. The demonstration study follows the integrated evaluation methodology, and gives a particular assessment of the proliferation resistance associated with a proliferating host State focusing upon the diversion from the spent fuel storage of a MPBR plant.

In order to evaluate the probability value of the diversion success, the study has provided: three top-level proliferation resistance measures addressing the inherent features of the system; a hypothesized safeguards approach for the system and a set of the plausible concealment tactics of the proliferator; an expert elicitation approach for evaluation of key model inputs; identification of the most attractive diversion pathway; uncertainty propagation of experts' inputs, sensitivity analyses of an ultimate outcome to input variables, and importance analyses of minimal path sets of success trees. Consequently, the study showed that the proposed methodology is an effective evaluation tool for comparison of advanced nuclear systems in terms of proliferation resistance. In addition, some limitations of the study and future work were also determined.