Office for Nuclear Regulation

Heysham 1 – Inspection ID: 52880

Executive summary

Date(s) of inspection

  • October 2023

Aim of inspection

The objectives of this intervention were:

  • To examine the adequacy of the licensee’s arrangements with regards to graphite core inspection during this outage;
  • To establish confidence that the various safety case commitments for core inspection and trepanning would be met;
  • To consider the quality of the examinations performed, both in terms of data quality and the adequacy of the training and understanding of those involved in the work being carried out.

Subject(s) of inspection

  • LC28 – Examination, inspection, maintenance and testing – Rating: Green

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

The purpose of this intervention was to undertake a Licence Condition (LC) 28 compliance inspection at EDF Energy Nuclear Generation Ltd’s (NGL’s) Heysham 1 (HYA) power station. The intervention took place on 17th October 2023, several weeks after the start of its 2023 periodic shutdown of reactor 1 (R1). The outage was scheduled to complete in early December. The purpose of the intervention was to inspect the adequacy of the licensee’s examinations and inspections of the graphite core and determine compliance with LC 28(1).

This intervention is one of a number of LC28 compliance inspections performed by ONR during the periodic shutdown of HYA R1. These inspections inform the ONR’s decision on whether to issue a licence instrument granting consent for the return to service of HYA R1 following its 2023 statutory outage.

This intervention specifically focused on the arrangements for graphite core examination, inspection and testing and the observations made by ONR specialist graphite inspectors during these periodic shutdown activities. My judgement is based on the findings of the intervention, the quality of the data I observed and the knowledge and experience of the licensee’s staff.


Following my intervention, I consider that the licensee’s arrangements with regards to graphite core inspection during this outage are suitable and adequate. In my opinion, the visual records and the data that I sampled were of adequate quality for NGL to form an accurate judgement.

At the time of my intervention, there was no reason to believe that the safety case requirements would not be met. A forthcoming assessment report will consider whether the results of the graphite core inspections are consistent with the graphite safety case, once the inspection schedule has been completed.

I have allocated an ONR IIS rating of ‘green’ – no formal action.