Application of ALARP Concept in Nuclear Power Plant Design — A Case Study in HPR1000

Abstract

As Low As Reasonably Practicable (ALARP) is one of the most important nuclear regulatory concepts in the UK Generic Design Assessment (GDA). ALARP requires that nuclear power plants have the duty to achieve the lowest level of residual risk provided this is reasonably practicable. Unlike As Low As Reasonably Achievable (ALARA), ALARP concept should be considered not only in radioprotection, but also in nuclear safety areas such as fault studies, structural integrity, etc. Different from the traditional licensing requirements in other countries, ALARP concept is not prescriptive but emphasizes self-evaluation, risk-orientation and balance of all aspects. It is therefore difficult to demonstrate that the design has reduced nuclear risks to an ALARP level without a systematic approach during the licensing. In this study, the UK context regulatory requirements of ALARP (including the Tolerability of Risk, Relevant Good Practice, Gross Disproportion, and Numerical Targets) are investigated based on which an ALARP approach for Hua-long Pressurized Reactor (HPR1000) is developed. In this approach, potential improvements can be identified through the review against Relevant Good Practice and risk insights. Risks can be reduced through the implementation of preferred options determined by optioneering process. The ALARP position of the whole plant design can be evaluated through holistic risk review. The ALARP approach has been successfully applied to HPR1000 and recognized by the UK authority during the GDA process. The ALARP approach facilitates the balance of safety, economy and environmental friendliness during nuclear power plant design, and can be guidance to the robust licensing and regulation.