Recycling alternatives for minor actinide and plutonium in a boiling water reactor

摘要

Recycling is an alternative for reducing minor actinide and plutonium stockpiles from depleted fuel assemblies. In the current study, it is proposed the use of a MOX fuel assembly called MOXIM-MA. It comprises 4 rods with minor actinides, 14 UO_2-gadolinium rods, 8 water rods, and 66 MOX fuel rods. This MOXIM-MA design is used in a 2027 MW_(th) BWR, reducing 0.130 kg HM of minor actinide and 5.042 kg HM of Plutonium per fuel assembly at discharge after discharge 4-operating cycles of 18 months each. The reactor core energy produced does not suffer any penalty by using this fuel assembly. There is no need for additional changes to the original control safety system. The radiotoxicity results show almost one magnitude order increase compared with standard UO_2 fuel assemblies for the same BWR reactor core. Still, this increase is the same magnitude experienced when MOX fuel assemblies without minor actinide are used. A twin reactor power plant, 2027 MWth per unit, with 20 and 25 years of operational life, is considered to propose a plutonium and minor actinide recycling strategy. Standard UO_2 fuel assemblies, at discharge for this plant, produce 0.135 kg HM of MA and 1.707 kg HM of plutonium. By recycling them, at least 6 depleted fuel assemblies are needed for each MOXIM-MA fuel assembly processed. The suggested strategy starts by considering the cumulative amount of minor actinide and plutonium coming from the depleted fuel assemblies discharged during the plant's operating life at the moment of this analysis. The study shows that the MOXIM-MA fuel assemblies will be used in only one of the reactor units in a once-through scheme. It describes how the auto recycling of plutonium and MA could be done to supply the MOXIM-MA fuel assemblies during the rest of the plant's operation. Results promise to deliver the plant's whole operation life a decrease of 39.50 in plutonium inventories and 12.70 in MA inventories, achieving this goal without penalizing energy production.