Effects of Pu and MA uniform and nonuniform distributions on subcritical multiplication of TRIGA Mark II ADS reactor

Highlights: • The effects of distributions of Pu/MA samples in TRIGA Mark II ADS core were numerically investigated. • The neutron flux and spectrum of the two distributions were studied. • Plutonium and minor actinides fission rate were slightly higher in nonuniform distribution than that in uniform distribution. • The maximum total fission rate in the core was achieved with Pu/MA uniform distribution. • Neutron multiplication and source efficiency increased in the case of Pu/MA uniform distribution. - Abstract: Plutonium (Pu) and minor actinides (MAs) are responsible for the majority of radiotoxicity, heat generation, and proliferation risk of nuclear spent fuel. Accelerator driven system (ADS) reactors can employ Pu and MA for transmutation and power generation within improved safety scheme. Pu and MA can be loaded in ADS reactor core in a variety of distributions. In this study, the effects of uniform and nonuniform distributions of Pu and MA samples loaded within enriched uranium fuel elements inside UT-TRIGA Mark II ADS reactor on neutron flux, neutron spectrum, fission rate, and subcritical multiplication parameters were numerically investigated using Monte Carlo MCNPX transport code. The type of distribution producing higher subcritical multiplication and source efficiency will contribute in minimizing the accelerator current requirements for ADS operation.