Office for Nuclear Regulation

Sizewell B – Inspection ID: 52090

Executive summary

Date(s) of inspection:

  • February 2023

Aim of inspection

​​​​​​​This report records the findings of an intervention visit to the Sizewell B Nuclear Power Station during the 2023 periodic shutdown. The intervention was undertaken to confirm the adequacy of the work conducted by the licensee, EDF Energy Nuclear Generation Limited (NGL), to comply with the requirements of Licence Condition 28, examination, inspection, maintenance and testing.

ONR inspectors carried out inspections against the requirements of Licence Condition 28: examination, inspection, maintenance and testing, to inform the ONR decision relating to the issue of a licence instrument for consent for return to service of Sizewell B following its periodic shutdown (Licence Condition 30). The activities of the intervention were items judged important to nuclear safety.

Subject(s) of inspection

  • LC 28 – Examination, inspection, maintenance and testing – Rating: GREEN

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

I visited site twice, approximately two weeks into the planned periodic shutdown and 3 weeks after the first visit. The aim of which was to witness key activities related to the full structural weld overlay and condensate storage tank work. I sampled the inspection work that had been undertaken as part of the inspection programme and was satisfied with what I found.

I discussed progress on examinations and inspections undertaken by the Pressure Systems Safety Regulations (PSSR) Competent Person (CP) during the periodic shutdown. I judge that, during my visit, the PSSR examinations were being managed effectively by the Licensee and the CP and no significant issues had been found.

I am content that NGL are managing the corrosion programme effectively and are actively seeking to incorporate the lessons learned into normal station operations.

I undertook a plant walk down during my visit, escorted by an NGL staff. NGL staff were able to provide satisfactory explanations of both the operation of the systems and the inspection/maintenance of the systems planned or already performed during the periodic shutdown.


I judge that, at the time of my visit to the Sizewell B nuclear power station, personnel were conducting their inspections in line with the pre-outage intentions documentation and associated inspection specifications. I judge that the Licensee was adequately managing any defects or anomalies identified.

ONR will maintain an oversight for any emerging issues, from the inspections that have yet to be completed and report on any outstanding issues in the structural integrity assessment report on the return to service of Sizewell B following this periodic shutdown.

Based on my intervention to date, I conclude that the licensee has performed the work to an adequate standard. I consider that, in accordance with ONR guidance on the application of inspection ratings, a green rating is appropriate.