Thorium Fuel Cycle Pilot Experiences at Oak Ridge National Laboratory

摘要

Based on actual plant-scale operations, the thorium-uranium fuel cycle has both advantages and disadvantages when compared to the uranium-plutonium fuel cycle which creates neutron-emitting minor actinides. An advantage of the thorium-uranium fuel cycle is the added safeguards radiation barrier of ~(233)U containing high levels of ~(232)U and its decay daughters, particularly ~(208)T1. However, the presence of the highly radioactive ~(208)T1, which emits a 2.6-MeV gamma ray, is a major economic and operational disadvantage because the higher radiation level requires shielded and remotely operated processing equipment, including that for fabrication of recycled ~(233)U fuel. Other disadvantages involve the difficulty of dissolving ThO_2 and the need for off-gas hold-up to capture the particulate decay daughters of ~(220)Rn, especially ~(208)T1.