Nuclear Science research supports the Department of Energy (DOE) in conducting R&D on advanced reactor concepts focusing on the conceptual design, operation, control, and safety of nuclear systems for the development of next generation reactors for terrestrial and space power applications. ORNL also identifies the requisite technologies requiring further R&D to evolve these advanced concept employing capabilities that include both analysis and modeling of reactor power systems combined with technology development and validation of such systems through unique experimental facilities.
Through DOE’s Office of Nuclear Energy (NE), ORNL is developing an advanced high-temperature reactor concept that integrates technologies from several other thermal power plant designs. This new class of reactors, known as Fluoride salt-cooled High-temperature Reactors (FHRs), features low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. While FHRs represent a distinct reactor class, they inherit desirable attributes from other thermal power plants whose characteristics provide general guidance on plant configuration, anticipated performance, and costs. As high-temperature plants operating at 700°C, FHRs can support either high-efficiency electricity generation or process heat production. FHR’s combination of liquid cooling and a high output temperature makes FHRs well suited for coupling to hydrogen production facilities and thereby to liquid hydrocarbon fuel production.
ORNL is performing R&D on advanced salt compatible alloys, ceramic composite materials, TRISO fuel fabrication, economic model development, licensing and safety evaluation, FHR system modeling tools development, high temperature instruments, and liquid salt compatible component development, as well as creating a roadmap for the overall FHR program. As part of the technology development for FHRs, ORNL has designed and constructed a liquid salt component test facility for establishing baseline operations with the coolant salts at temperature with materials and in developing appropriate components suitable for salt operations.