Radiotoxicity implications and reduction strategies of minor actinide in a boiling water reactor

Radiotoxicity implications for the reactor use of a previously proposed BWR fuel assembly called “MAc”, which contains 4 minor actinide bearing rods, are assessed. Use of this type of fuel assembly in a BWR with a nominal power of 2027 MWt shows a reduction of 135.30 kg HM of minor actinide per 18-month operating cycle when the whole core is composed of “once-through” MAc fuel assemblies, it is achieved without any penalty in reactor core energy generation and without violating any of the standard reactor safety constraints. The radiotoxicity results show that the use of this type of fuel assembly, that contains minor actinide, does not increase the amount of radiotoxicity that is given when the core is composed by standard UO2 fuel assemblies. A proposed strategy for minor actinide recycling is analyzed where a nuclear power plant that is composed by two 2027 MWt reactor units with 25 and 20 years of operation, respectively is taken as the base case. Results show that at least 4 BWR depleted fuel assemblies are needed to get enough minor actinide material to provide the 4 minor actinide bearing rods for the MAc fuel assembly. The proposed strategy shows the amount of cumulative depleted fuel at the moment of this analysis and the number of fuel reloads that can be supplied along with the total reduction of minor actinide assuming a once-through use of the MA fuel assemblies. Results of this strategy show a decrease in the amount and volume of depleted fuel because the use of the MAc fuel assemblies, minor actinide recycling strategy achieves the goal of radiotoxicity reduction without any disturbance to the power plant energy production.