Executive summary
Date(s) of inspection: April 2024
Aim of inspection
- 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) Torness (TOR) power station.
This intervention is one of a number of LC28 compliance inspections performed by ONR during the periodic shutdown of TOR Reactor 1 (R1). These inspections inform the ONR’s decision on whether to issue a licence instrument granting Consent for the return to service of TOR R1 following its 2024 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.
Conclusion
Following my intervention, I consider that the licensee’s arrangements with regards to collection of graphite core inspection data 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 noted shortfalls in arrangements and adherence to said arrangements in other aspects of the graphite related activities, namely:
- Tracking and management of Lifting Operations and Lifting Equipment Regulations (LOLER) 98 defects.
- Control of final versions of Engineering Change (EC) documents.
- Guidance for Seal Ring Groove Wall (SRGW) fragment identification to initiate load / no load decisions.
- Evidence of training needs for key graphite inspection personnel.
ONR Issues have been raised seeking visibility of the resolution of the revised guidance for SRGW fragment identification (ONR Issue 12506) and evidence of training needs (ONR Issue 12504). The shortfalls associated with LOLER defect management and control of EC documents have been communicated with either the project inspector or specialist inspector and will be managed through routine regulator engagements.
Whilst shortfalls have been identified, I consider 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.