Safety Design Criteria for Generation IV Very High Temperature Reactor System - 2023

The Generation-IV International Forum (GIF) has been developing Safety Design Criteria (SDC) for specific Gen-IV systems. To date, the SDC are completed for SFR, LFR and GFR systems. This report focuses on SDC for VHTR system with the objective of establishing reference requirements for the safety design of VHTR structures, systems, and components consistent with the GIF safety goals and basis for safety approach. 

Chapter 1 provides a background and introduces the objectives and SDC formulation principles. Chapter 2 outlines GIF safety goals and basic safety approach, introduces the fundamentals of VHTR safety approach, and discusses unique VHTR features that require specific revisions. In Chapter 3, eighty-five criteria for the overall safety design and specific structure, system and component design are described in the same structure of IAEA SSR 2/1, “Safety of Nuclear Power Plants: Design Specific Safety Requirements” on which the GIF SDCs for specific Gen-IV systems are based. The differences between the IAEA SSR 2/1 requirements and the VHTR-specific criteria are also captured in Appendix A with a side-by-side comparison of the original and revised requirements as well as the markups. The rationale for major revisions and deviations from the original IAEA SSR 2/1 requirements are captured in Chapter 2. A glossary covering specific terminology for the generation-IV systems in general, and VHTR system in particular, is also included. Several important terms, as defined in the IAEA safety glossary, are also incorporated in the glossary for convenience. 

The potential users of this report are expected to be the VHTR concept developers as well as international and national regulatory organizations. Due to similarities of VHTR systems with the modular HTGR concepts currently being pursued world-wide, we envision its use by the modular HTGR designers as well.