The decommissioning costs of a nuclear power plant are several hundreds of millions of dollars, with waste disposal alone predicted to cost over $100 million by the U.S. Nuclear Regulatory Commission. While investment in advanced nuclear deployment continues to grow, there has yet to be a comprehensive study on the decommissioning costs of advanced reactors.

This study creates a generic computational framework to estimate the disposal costs of major equipment for advanced reactors. The framework is compatible with both CINDER90 and ORIGEN, where reaction rates are calculated from MCNPX, SCALE, or other neutron transport packages. The framework is benchmarked against the disposal costs for a pressurized water reactor’s components (core shroud, barrel, and reactor pressure vessel), resulting in a disposal cost of ~$0.3/MWh.

The same methodology is then applied toward estimating disposal costs for a molten salt reactor (MSR). The MSR analysis focuses on the activity and disposal costs of the graphite reflectors, core can/shroud, and reactor vessel. The metal components are modeled as either SS316 or Hastelloy N with an operating period of 5 to 10 years. The core can is greater than Class C waste, while the vessel is Class C waste for SS316. For Hastelloy, the waste classification is dependent on the operating lifetime. A 10-year safe storage is assumed for the MSR to reduce its disposal costs.

It was found that the disposal cost of graphite reflectors alone would reach $1/MWh. Overall, the MSR nuclear equipment cost could be significantly higher (~10×) than that of large water-cooled reactors. The difference is driven by the material selection, lack of economy of scale, and shorter lifetimes.