Office for Nuclear Regulation

Heysham 2 – Inspection ID: 52729

Executive summary

Date(s) of inspection:

  • June 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 2 (HYB) power station.

This intervention is one of a number of LC28 compliance inspections performed by ONR during the periodic shutdown of HYB Reactor 8 (R8). These inspections inform the ONR’s decision on whether to issue a licence instrument granting Consent for the return to service of HYB R8 following its 2023 periodic shutdown, as required by LC30(1).

This intervention specifically focused on arrangements for the graphite core examination, inspection and testing. I judged this intervention 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 activities 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 and enable sentencing of the cracks.

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.