A streamlined approach for the seismic hazard assessment of a new nuclear power plant in the UK

Abstract

This article presents a streamlined approach to seismic hazard assessment aimed at providing regulatory assurance, whilst acknowledging commercial and program constraints associated with the development of safety-critical facilities. The approach was developed based on international best practice and followed the spirit of the Senior Seismic Hazard Analysis Committee (SSHAC) Level 2 requirements, while incorporating the key features of the SSHAC Level 3 process aimed at achieving regulatory assurance, but with a more flexible implementation. It has also benefited from experience gained by others regarding the implementation of the SSHAC process in projects in the USA, Switzerland and South Africa. The approach has been successfully applied as part of the Safety Case for the new-build nuclear power plant at Hinkley Point, UK. The proposed approach can be considered as a cost-effective solution for the seismic hazard evaluation of safety-significant facilities where a high level of regulatory assurance is required.

Earthquake hazard and risk analysis for natural and induced seismicity: towards objective assessments in the face of uncertainty

“…While a Level 3 study should continue to be viewed as the optimal choice to achieve regulatory assurance for a site-specific PSHA at a nuclear site, encouragement should be given to all studies that can move closer to this target, and in that regard the option of an augmented or enhanced Level 2 study is a positive development. In effect, this is the approach that has been applied at some UK new-build nuclear sites (Aldama-Bustos et al 2019).…”

Probabilistic seismic hazard assessment for a new-build nuclear power plant site in the UK

“…Based on experience with the UK regulatory environment, through decades of involvement in nuclear-related projects, and on the understanding of international best practice for the evaluation of the seismic hazard for nuclear facilities, core members of the project delivery team developed a cost-efficient methodology for the PSHA, presented in the companion paper by Aldama-Bustos et al (2018). The proposed methodology incorporated "relevant good practice", likely to satisfy ONR's requirements, whilst acknowledging commercial and program constraints associated with the development of NPPs faced by utility operators in the UK.…”

Strategies for Comparison of Modern Probabilistic Seismic Hazard Models and Insights from the Germany and France Border Region

“…Model migration differs from dual implementation, a practice becoming more widely adopted for quality assurance for critical facilities that executes models in multiple software side by side, identifying discrepancies that are then discussed and potentially resolved (e.g., Bommer et al, 2015;Aldama-Bustos et al, 2019). Migration assumes a reference seismic hazard output from the original software, which the target software aims to reproduce regardless of whether the calculation processes of the original software are deemed optimal.…”

“…As they are elemental in nature, however, they cannot necessarily predict the extent to which different codes will yield different outputs for seismic hazard at a given location, where many modelling differences come into play. The importance of this type of application and the benefits of multi-software implementations of a seismic hazard model as part of a quality assurance (QA) process for the design of critical facilities has been highlighted emphasized by Bommer et al (2015) and Tromans et al (2019), among others, and is becoming more widely used in practice. The QA application is only one context, however, and arguably a favourable one in which multiple parties are involved and resources often made available to document and debate the implementations, and to resolve discrepancies as and when they emerge.…”