Safety Classifications for the Fusion DEMO Plant of Korea

Regulatory requirements and industrial codes and standards (C&S) are to be compulsory top-tier prerequisites for the design and construction of the fusion DEMO plant of Korea (DEMO Plant) as it will have safety-related functions to mitigate radiation hazards to the environment. However, these prerequisites will be developed in parallel with the design and construction of DEMO Plant due to the first-of-a-kind nature of the DEMO Plant. To overcome this dilemma, a tentative set of general design criteria and classification criteria that are to be applicable for the design studies of DEMO Plant is proposed, making use of the commonalities between the DEMO Plant and existing nuclear power plants (NPPs). To determine the tentative set, the radiation release to the environment and consequences of the postulated events in the DEMO Plant are analyzed with rough approximation assuming the inherent safety of a fusion DEMO reactor. The classification criteria of the tentative set include safety class, IEEE electrical classes, quality groups, and seismic categories for the structures, systems, and components of the DEMO Plant. As it will take considerable time and substantial amounts of investment to develop the regulatory requirements and C&S, the use of ASME Section III for the design study of DEMO Plant is also proposed to make the best use of the commonalities between the DEMO Plant and existing NPPs.