Office for Nuclear Regulation

Hinkley Point B System Based Inspection (SBI27) - Reactor Safety System

Executive summary

Purpose of Intervention

The purpose of this intervention was to undertake a planned Licence Conditions (LCs) System Based Inspection (SBI) for the Reactor Safety System (RSS) trip parameters at EDF Energy Nuclear Generation Limited’s (NGL) Hinkley Point B (HPB) Power Station.

This work was carried out in line with the planned inspection programme in the HPB Integrated Intervention Strategy (IIS plan) for 2020-21.

Interventions Carried Out by ONR

The objective of this SBI of the RSS was to judge whether the arrangements are adequately implemented and in accordance with the requirements of the relevant safety cases. The RSS primarily monitors reactor or plant conditions and initiates a reactor trip should reference levels of measured parameters be exceeded. Through examination of this system, compliance inspections were performed against LCs which are applicable provisions of the Energy Act 2013.

The inspections were based on sampling the implementation of the licensee’s arrangements at HPB power station against the LCs and was performed in line with ONR’s guides for technical inspections. (

Due to the current government advice on COVID-19 restrictions, the majority of the intervention was carried out remotely using video conferencing with the plant walkdown being the only aspect undertaken at HPB.

The Inspection was undertaken by two control and instrumentation specialists, a fault studies specialist and the nominated site inspector.

Explanation of Judgement if Safety System Not Judged to be Adequate

From the intervention and details examined, we judge that the arrangements associated with the RSS are adequately implemented and consistent with the safety case requirements. 

Key Findings, Inspector's Opinions and Reasons for Judgements Made

From the System Based Inspection of the RSS, we made the following conclusions:

The intervention findings were shared with EDF NGL. They have satisfactorily responded to the majority of these findings during the intervention. There remain a few minor observations to be addressed by EDF NGL and they will be managed by the nominated site inspector via routine regulatory engagement.

Conclusion of Intervention

From the evidence examined during this intervention, we judged that there were no matters that have a significant adverse impact on nuclear safety. We consider EDF NGL have adequately implemented their arrangements to ensure nuclear safety is maintained.  There was no formal regulatory action raised from the outcomes of this intervention.  We judge the overall inspection rating is green.