Application of Technology Neutral Methodology for Assessment of Defence in Depth Application for Generation IV Reactor Systems

The Generation IV International Forum (GIF) Charter envisions the safe and reliable operation of nuclear systems as an essential priority in the development of next-generation systems. Safety and reliability goals broadly consider operations, improved accident management and minimization of consequences, investment protection, and reduced need for off-site emergency response. This emphasis on enhanced safety and reliability has been duly reflected in the Policy Group’s selection of the system designs, as well as in recognition of the need to establish in 2004 a system cross cutting methodology working group on Risk and Safety ( RSWG). The group was charged with the responsibility to promote a homogeneous approach to safety and quality in the design of Generation IV systems and define the framework for safety design and evaluation methodology which could be applied to all reactor systems. It was recognized that development of advanced and enhanced safety assessment methodologies might be needed for this purpose. The paper provides an overview of the recent GIF Risk and Safety Working Group developments of technology neutral nuclear safety requirements and safety assessment methodologies. In particular, it addresses the applicability of “Objective Provision Tree” (OPT) methodology for verification of defence in depth application for new designs, as well as on the need to complement this methodology with traditional safety assessment techniques such as deterministic accident analysis and probabilistic safety assessments. The later are needed to judge on the adequacy of the safety provisions and relative importance of different provisions. The experienced gained with the pilot applications of the OPT methodology to different reactor designs will be also discussed along with the further effort needed to validate the applicability of this new proposed methodology for GIF reactor systems.JRC.F.5-Nuclear operation safet