US EPA

3787680 

Journal Article 

Optimization of plutonium and minor actinide transmutation in an AP1000 fuel assembly via a genetic search algorithm 

Washington, J; King, J 

2017 

1 

Nuclear Engineering and Design
ISSN: 0029-5493
EISSN: 1872-759X 

311 

199-212 

10.1016/j.nucengdes.2016.11.030 

WOS:000392683100018 

The average nuclear power plant produces twenty metric tons of used nuclear fuel per year, which contains approximately 95 wt% uranium, 1 wt% plutonium, and 4 wt% fission products and transuranic elements. Fast reactors are the preferred option for the transmutation of plutonium and minor actinides; however, an optimistic deployment time of at least 20 years indicates a need for a near-term solution. Previous simulation work demonstrated the potential to transmute transuranic elements in a modified light water reactor fuel pin. This study optimizes a quarter-assembly containing target fuels coated with spectral shift absorbers for the transmutation of plutonium and minor actinides in light water reactors. The spectral shift absorber coating on the target fuel pin tunes the neutron energy spectrum experienced by the target fuel. A coupled model developed using the NEWT module from SCALE 6.1 and a genetic algorithm module from the DAKOTA optimization toolbox provided performance data for the burnup of the target fuel pins in the present study. The optimization with the coupled NEWT/DAKOTA model proceeded in three stages. The first stage optimized a single-target fuel pin per quarter-assembly adjacent to the central instrumentation channel. The second stage evaluated a variety of quarter-assemblies with multiple target fuel pins from the first stage and the third stage re-optimized the pins in the optimal second stage quarter-assembly. An 8 wt% PuZrO2MgO inert matrix fuel pin with a 1.44 mm radius and a 0.06 mm Lu2O3 coating in a five target fuel pin per quarter-assembly configuration represents the optimal combination for the transmutation of plutonium and minor actinides in the LWR environment considered in this study. (C) 2016 Elsevier B.V. All rights reserved.