A preliminary neutronic evaluation of the high temperature nuclear reactor (HTTR) using reprocessed fuel

•The HTTR was simulated using reprocessed fuels spiked with thorium and depleted uranium.•The effective neutron multiplication factor and the nuclear fuel evolution during the burn-up were analyzed.•The results indicated that reprocessed fuels can be used in the HTTR.

The High Temperature Engineering Test Reactor (HTTR), a 30 MWth, graphite-moderated, helium-cooled reactor constructed by the Japanese government was simulated using reprocessed fuel obtained by UREX+ and spiked with thorium-232 and with depleted uranium. The effective neutron multiplication factor and the nuclear fuel evolution during the burn-up were analyzed. This study was performed using the ORNL SCALE 6.0 code, with CSAS6 and TRITON6 control modules. The results show in a preliminary way that the burn-up of reprocessed fuels in the HTTR core is possible, although the fissile material quantities should be increased while compared with the enrichments of the standard fuel.