IMPLICATIONS OF PLUTONIUM ISOTOPIC SEPARATION ON CLOSED FUEL CYCLES AND REPOSITORY DESIGN

摘要

Advances in laser enrichment may enable relatively low-cost plutonium isotopic separation creating a new unexplored dimension in fuel cycle options. This may have large impacts on light water reactor (LWR) closed fuel cycles and waste management. If~(240)Pu is removed before recycling plutonium as mixed-oxide (MOX) fuel, it would dramatically reduce the buildup of higher plutonium isotopes, americium, and curium. Plutonium-240 is a fertile material and thus can be replaced by ~(238)U. Eliminating the higher plutonium isotopes in MOX fuel increases the Doppler feedback, simplifies reactor control, and allows infinite recycle of MOX plutonium in LWRs. Reducing production of ~(241)Pu by removal of ~(240)Pu reduces production of~(241) Am-the primary heat generator in spent nuclear fuel after several decades. Reducing heat-generating ~(241)Am would reduce repository size, cost, and waste toxicity. Avoiding ~(241)Am avoids its decay product ~(237)Np, a nuclide that partly controls long-term oxidizing repository performance. The ~(240)Pu could be added to the high-level waste for disposal. Some of these benefits also apply to plutonium recycled into fast reactors. However, the benefits are fewer because in a fast neutron spectrum, ~(240)Pu is both a fissile material and a fertile material. There would be incentives to separate ~(242)Pu and dispose of it as a waste.