Adaptation of Nuclear Fission Cost Estimation Tools for Fusion Energy Systems

Nuclear fission cost estimation tools have been developed and refined over decades, producing structured frameworks such as the Code of Accounts (COA) and the Algorithm for the Capital Cost Estimation of Reactor Technologies (ACCERT). Fusion energy systems share fundamental economic characteristics with fission reactors, including high capital costs, low operating costs, and similar secondary plant systems, yet no concept-agnostic fusion cost estimation tool integrated with broader physics workflows currently exists. This paper extends ACCERT to fusion energy systems by porting cost models from existing fusion codes, including PROCESS and TEAm, into a common COA framework. The capability is demonstrated through a comparative sensitivity analysis of three magnetic confinement fusion concepts—tokamaks, stellarators, and tandem mirrors. Rather than comparing absolute costs across systems of differing scale, this work focuses on relative cost sensitivities to key uncertain parameters including superconductor materials, lithium-bearing blanket materials, neutron multipliers, shielding, and vacuum vessel materials. Results show that magnets and breeding blankets are primary cost drivers across all three concepts, while sensitivities differ meaningfully based on confinement scheme and blanket technology selection. The ACCERT framework enables direct integration with external physics codes and optimization workflows, providing a flexible, concept-agnostic foundation for future fusion technoeconomic analysis.