Proliferation resistance assessment of a typical pebble bed reactor fuel

Abstract A study is carried out to assess the proliferation resistance (PR) of pebble bed reactor (PBR) fuel using two methods. The Proliferation Resistance Analysis and Evaluation Tool for Observed Risk (PRAETOR) code is the first method, which employs 68 attributes (intrinsic and extrinsic) to assess the overall PR. Forty-six uranium and plutonium diversion scenarios are analyzed with initial 235U enrichments from 4.95 to 17 wt% and a fuel burnup varying from 5 to 90 GWd/MTU. PRAETOR code gave same PR values (within 1%) for all the 46 scenarios and not able to distinguish between the uranium and plutonium diversion scenarios. A second PR analysis method employing only four attributes is developed and analyzes the intrinsic PR of plutonium spheres, which is able to distinguish the intrinsic PR of all the 23 plutonium diversion scenarios analyzed. Data needed for PR assessments are generated using neutronics simulations of PBR fuel irradiation.