Executive summary
Date(s) of inspection:
November 2025
Aim of inspection
The aim of this intervention is to support ONR with any future LC 30 permissioning decision. The intervention will:
- examine the adequacy of the licensee’s arrangements with regards to graphite core inspection during this outage;
- establish confidence that the various safety case commitments for core inspection and trepanning would be met;
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
Completion of these inspection activities will enable us to make a judgement on the licensee's ability to satisfy ONRs LC 28 compliance expectations with respect to graphite.
Subject(s) of inspection
- LC 28 - Examination, inspection, maintenance and testing - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
This intervention is one of a number of LC28 compliance inspections performed by ONR during the periodic shutdown of HYA Reactor 2 (R2). These inspections inform the ONR’s decision on whether to issue a licence instrument granting Consent for the return to service of HYA R2 following its 2025 periodic shutdown, as required by LC30(1).
This intervention specifically focused on arrangements for the graphite core examination, inspection and testing, specifically the control rod channel trepanning activities. As part of the inspection, I reviewed documentary evidence, spoke to the operator and attended operator governance meetings to gain assurance of the adequacy of the licensees arrangements. 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.
Conclusion
I spoke to a number of personnel who were involved in the graphite core inspections during the periodic shutdown. The personnel that I spoke to were knowledgeable and were prioritising the delivery of high-quality inspection results despite time pressures.
Following my intervention, I am content that the licensee’s arrangements, with regards to the collection of graphite core inspection data, during this outage are suitable and adequate.
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.
Whilst areas for consideration have been identified, I judge them minor in nature and do not have a material effect on the generation of graphite inspection data, hence I have allocated an ONR IIS rating of ‘GREEN’ – no formal action.