This report addresses a requirement in section 2001(b)(3) of the Energy Act of 2020 as well as a request in the House Report accompanying the Energy and Water Development and Related Agencies Appropriations Bill, 2022 for the Department of Energy (“the Department” or DOE) to report on the use of thorium and uranium-233 (U-233) U-233 as fuel for advanced nuclear reactor research, development, demonstration, or commercial application purposes. The Energy Act of 2020 directs the Department to provide a report describing the potential use of thorium fuel and U-233 in future Generation IV reactor designs, and in current operating light water reactors (LWRs). In 2022, the Department received a congressional request to provide a report describing whether it is working with other nations to develop thorium molten-salt reactors (TMSRs). In addition, Congress requested the Department to provide suggestions and considerations for Congress regarding the development of a domestic TMSR program. This report address both the statutory requirement and the House Appropriations request.