The impact of refueling schemes on the proliferation resistance of a pebble bed reactor

Abstract

Proliferation resistance (PR) evaluations of discharged fuel from a pebble bed reactor (PBR) that employs one-batch, single-pass, and multi-pass refueling schemes were performed. Four attributes (heat load, radiation dose rate, spontaneous fission neutron rate, and Rossi-α) of 8-kg plutonium (Pu) were used for the PR evaluations. Neutronics simulations of China’s HTR-10 PBR were conducted to derive the attribute values. The average fuel burnups for one-batch, single-pass, and multi-pass schemes were 64, 82, and 80 GWd/MTU, respectively. The fissile Pu content in PBR used fuel for all the three refueling schemes was found to be about 80%, very high compared to 60% in a large light water reactor, which led to the PR values of the PBR used fuel being low. The PR values were statistically the same regardless of the refueling schemes used because the total and fissile Pu masses varied only within 5% among these three schemes.