RADIONUCLIDE INVENTORY CALCULATIONS FOR DEPLETED FUEL IN A SMALL FLUORIDE MOLTEN SALT REACTOR AND A MICRO-SIZED HIGH-TEMPERATURE GAS-COOLED REACTOR

Abstract

The small modular reactor (SMR) is considered to be an enabling technology for providing economical and clean energy in remote areas in Canada. To ensure the SMR technology is developed within a robust framework that addresses environmental and waste management concerns, data are required on radionuclide inventory and characteristics of SMR depleted fuel at the end of reactor service life and at various times thereafter. These data provide essential inputs to assessment of fuel recycle analysis, understanding of environmental impact, and strategy development for waste disposal and management. In this paper, radionuclide inventories of depleted fuel in a small fluoride molten salt reactor (sm-FMSR) and a micro-sized high-temperature gas-cooled reactor (m-HTGR) are calculated using the Monte Carlo neutron transport code Serpent and the point neutron activation and decay code SCALE/ORIGEN. The inventory calculation methods for two selected small modular reactors are described, and radionuclide inventory results from Serpent and ORIGEN are compared. Overall, ORIGEN produces more conservative results than Serpent for both sm-FMSR and m-HTGR. The major characteristics of the radionuclide inventories are discussed for both SMRs.