- IR number: 22-027
- Date: May 2022
- LC numbers: 28
Purpose of Intervention
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 2 (R2). These inspections inform the ONR’s decision on whether to issue a licence instrument granting Consent for the return to service of TOR R2 following its 2021 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.
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.
Interventions Carried Out by ONR
The inspection was held on the 16 and 17 May 2022. My inspection covered the graphite core inspection activities carried out during the shutdown. Due to the early stage of the graphite inspections, I also sampled the quality documentation from the recent January 2022 TOR R1 graphite inspection as these used the same processes.
At the time of my intervention, NGL had completed 2 out of 30 New In-Core Inspection Equipment (NICIE2) inspections. As part of the intervention,
- I examined some of the visual records to form an ONR view as to the quality and adequacy of the data being recorded;
- I reviewed the training records and their administrative arrangements to ensure the adequacy of the graphite core inspections;
- Observed a graphite activity and checked the documentation being used by the operators.
This intervention report does not comment on the significance of any findings as these will be addressed by ONR in a separate assessment. ONR’s assessment will however take note of the findings of this intervention.
Explanation of Judgement if Safety System Not Judged to be Adequate
Key Findings, Inspector’s Opinions and Reasons for Judgements Made
The target requirement for this periodic shutdown is to carry out 20 fuel channel inspections of the bore, one control rod channel inspection and trepan 35 samples from the graphite bricks. At the time of this intervention, NGL had completed 2 fuel channel inspections which included visual and bore measurements.
I spoke to a number of personnel who were involved in the graphite core inspections during the periodic shutdown. The personnel that I met were knowledgeable and were prioritising the delivery of high quality inspection results despite time pressures. Noting the early stage of the inspections I sampled quality documentation from the recent January 2022 TOR R1 Graphite Inspection Outage which followed the same processes. I noted some inconsistencies in the completion of quality documents. NGL responded positively to the observation and acted to learn from event. From discussions around the quality documentation, I am content that the quality of the data collected was not affected. I am also content that NGL have taken appropriate action to identify and communicate any corrective actions.
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 I was content that NGL had a process in place to ensure only suitable qualified and experienced (SQEP) personnel perform the graphite inspections.
Conclusion of Intervention
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 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.