Risk Informed Safeguards Approaches for Molten Salt Reactors

Active research on the viability of molten salt reactor (MSR) for electricity generation has reemerged in the recent years. Most of the research focus currently is on the design, development, safety and economics aspects of MSR. This paper presents an analysis on the proliferation resistance (PR) of a typical (albeit historic) MSR design by reviewing the intrinsic and extrinsic attributes (barriers) against nuclear proliferation. As part of this initiative, a proliferation resistance assessment tool, PRAETOR (Proliferation Resistance Analysis and Evaluation Tool for Observed Risk) developed at Texas A&M University was utilized. PRAETOR employs a multi-tiered analysis based on the multiplicative Multi Attribute Utility Analysis (MAUA) method that uses 68 input attribute values which captures the nonproliferation aspects of an MSR. The analysis is carried over four stages to provide a final proliferation resistance value between zero and one. The PR value is indicative of the nonproliferation characteristic of the nuclear system being analyzed and is very useful metric for comparing nuclear fuel cycle systems. This paper focuses on the diversion of nuclear material within molten salt reactors (MSRs)-specifically the MSR-Experiment and its successor the Molten Salt Breeder Reactor (MSBR). While these MSR technologies do not completely depict todays MSRs, they will serve as benchmark cases, and they provide insight into the parameters of key importance for the future safeguards of MSRs. The PR metric obtained for MSRE and MSBR are compared to a current generation pressurized water reactor (PWR). From the study, it is concluded that the overall PR value for all the cases analyzed are approximately 0.5 (details of the meaning of the PR value will be provided below). This is due to the fact that the MSRE and MSBR are experimental reactors that were constructed at small scale and at a time period that had not been introduced to safeguards yet. Hence, with those limitations, the historic MSRs are as resistant as a current generation PWRs. Thus, this preliminary study shows that newer MSRs which could incorporate safeguards by design can likely provide better nonproliferation characteristics than the historic designs.