Using a modified CINDER90 routine in MCNPX 2.6.0 for the prediction of helium production in minor actinide targets

► Modification of the CINDER90 depletion code used by MCNPX 2.6.0. ► Testing using the Sodium-Cooled Heterogeneous Innovative Burner Reactor model. ► Verified using the ORIGEN-ARP module of SCALE6. ► Verified by depleting a single Sodium Fast Reactor assembly. ► Gas production rates are more accurate for heterogeneous MA target rods. Fast reactors containing heterogeneous minor actinide (MA) target rods are now being modeled. When studying transmutation in these rods, helium production from α-decay must be considered since it is produced in substantial quantities. This research utilized an innovative method to calculate gas production by modifying the CINDER90 depletion code used by MCNPX 2.6.0 to include helium production from α-decay. The modified CINDER90 code was verified using the ORIGEN-ARP module of SCALE6. It was tested using the Sodium-Cooled Heterogeneous Innovative Burner Reactor model created at the University of South Carolina. It is recommended that the modified version of the cinder.dat file be distributed in subsequent MCNPX 2.6.0 releases for use in fast reactor calculations using heterogeneous MA target rods since it includes helium production otherwise not available from the current version.