Likely U.S. Regulatory Considerations for D-T Fusion Power Reactors

Abstract

The Electric Power Research Institute outlined three criteria important for a commercially viable fusion power plant: competitive electric power cost, regulatory simplicity, and public acceptance. In this paper we consider likely U.S. regulatory considerations for deuterium-tritium (D-T) fusion power reactors, relying on existing criteria and past actions by the U.S. Nuclear Regulatory Commission, which has asserted regulatory jurisdiction over U.S. commercial fusion reactors. We begin with consideration of a basic D-T fusion reactor, independent of plasma confinement approach. Because tritium and radioactivity are present, likely regulation will require containment structures and various safety measures for each component. Regulators are certain to require that all nuclear components of the system be housed in an overall containment vessel that must be held at less than atmospheric pressure to contain any leakage of tritium, radioactive corrosion products, radioactive coolant, and activated elements in the air. In addition, regulators are sure to require plant structure and operations that minimize the potential for clandestine plutonium breeding. Next, we add superconducting magnets and a plasma dump (divertor) to the basic system and recognize the small but nonzero probability of those magnets explosively quenching, potentially causing reactor damage and dramatically increasing containment vessel pressure. Finally, we consider ITER as prototypical of a D-T–fueled fusion power reactor. Because ITER-like systems are subject to damaging plasma disruptions, regulators are almost certain to require safeguards against such events significantly damaging first walls and subsystems. Finally, we believe that regulators are not likely to back off significantly in requirements related to the deuterium-deuterium and D3He fuel cycles even though the tritium production and the neutron damage in the latter fuel cycle are significantly below those in a D-T system. However, regulations for p11B and 3He3He fuel cycles are certain to be dramatically less demanding because of the lack of tritium and essentially no neutron production.