Accurate capital and operational cost data for advanced nuclear concepts are critical for meaningful technoeconomic analyses. However, the data for advanced reactors disposal costs are often missing or assumed to be the same as for light water reactors. Decommissioning costs should be estimated in a reliable way to establish adequate decommissioning funds. This work presents the projected disposal costs for the horizontal compact high-temperature gas-cooled reactor (HC-HTGR) components to provide insights into HTGR decommissioning costs relative to pressurized water reactors (PWRs).

This paper identifies the waste classifications for the key equipment, including the core barrel and reactor pressure vessel (RPV) cylinder, and the graphite reflector components of the HC-HTGR design. Furthermore, this work discusses the neutron irradiation effects and their impact on the integrity of the barrel, RPV, and graphite reflector against material property changes. The concentrations of radionuclides computed during activation analysis were used to estimate the disposal costs of the HC-HTGR components for immediate dismantlement after 40 years of operating lifetime and after a 10-year decay period. Overall, the disposal costs of the HTGR’s core barrel, RPV cylinder, and graphite reflectors will be 10 times higher than large PWR costs on a per energy produced basis.