The Development of a Hybrid Nuclear Requirements Hierarchy (HNRH) and its Application to a Non-Specific Fusion Facility

This paper forms a concluding article resulting from a several workpieces carried out during 2021—2022 as part of a research project on fusion hosted by the Nuclear Futures Institute (NFI) at Bangor University. The project considered current approaches to design safety (and associated topics, including security and environmental risk) in a wide range of highly regulated industries, both nuclear and non-nuclear. A comparison mapping between nuclear and non-nuclear sectors was developed, and this led to: a) The development of a Hybrid Nuclear Requirements Hierarchy (HNRH). b) The application of the HNRH to a non-specific fusion application. It is these that are the focus of this paper. By the nature of its derivation, the HNRH is applicable to or suitable for adaptation for any “hybrid nuclear” application, i.e. a design or facility where the expected radiological risk contributes only a small part to its overall safety risk profile (this small part also when considering its surroundings and operating environment as a whole, not purely considering its internals, internal hazards, or only the impact of untoward events in its immediate vicinity). This may occur where the “nuclear quota” of the design (or through operation of said design) is evidently minimal, either by design or by a low level of consequence or impact of a radiological hazard in the event of a system failure or other mishap.