Office for Nuclear Regulation

Sizewell B – Inspection ID: 51248

Executive summary

Date(s) of inspection:

  • November 2022

Aim of inspection

The aim of this intervention was to undertake a planned licence condition (LC) compliance inspection of LC 7 (incidents on the site) at Sizewell B.

This inspection was undertaken as part of a series of planned inspections described in the Integrated Intervention Strategy for Sizewell B.

Subject(s) of inspection

  • LC 07 – Incidents on the site – rating: Green

Key findings, inspector’s opinions and reasons for judgement made

I reviewed a sample of recent investigation reports, and discussed the reports with the relevant authors. I was content that the investigations had identified direct and root causes and, in particular, where human error was identified there was an understanding of the factors leading to it. Actions had been placed to prevent recurrence and were being progressed. I considered the investigators to be appropriate qualified and experienced to investigate the incidents in question.

I also discussed the training and monitoring of investigators and investigations with the corrective action plan coordinator, and was satisfied that the incidents of highest significance are investigated by well-qualified and experienced investigators. Less significant investigations are carried out by technically competent individuals who have either undergone appropriate training or who are being mentored by an experienced investigator. The licensee demonstrated to me that progress with, and effectiveness of, investigations and their subsequent action plans is tracked at the corrective action review board.


On the basis of the evidence sampled at the time of the inspection, I judge that EDF NGL has adequately implemented its arrangements for LC 7 at Sizewell B in the areas inspected. Noting the ONR guidance on inspection ratings, it is my opinion that an inspection rating of green (no formal action required) is merited here.

I further consider that no changes to the IIS plan for Sizewell B are necessary as a result of this inspection.