- Site: Heysham 2
- IR number: 21-026
- Date: June 2021
- LC numbers: 28
Executive summary
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) 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 7 (R7). These inspections inform the ONR’s decision on whether to issue a licence instrument granting consent for the return to service of HYB R7 following its 2021 periodic shutdown, as required by LC30(1).
This intervention specifically focused on arrangements for 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
A site visit was conducted with the following objectives:
- To provide regulatory confidence in the implementation of the HYB R7 Outage Intentions Document in relation to Graphite.
- To provide evidence to inform the ONR decision relating to the issue of a Licence Instrument for a Consent for return to service of at HYB R7 on completion of the work undertaken during the outage.
These discussions were held on the 7 June 2021. My inspection only covered the graphite core inspection activities carried out during the shutdown.
At the time of my intervention, NGL had completed 10 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 those findings, which are being 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
N/A.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
The target requirement for this periodic shutdown is to carry out 30 fuel channel inspections of the bore and one control rod channel inspection. At the time of this intervention, the NGL had completed 11 channel inspections which included visual and bore measurements.
I held discussions with a number of personnel who were involved in the graphite core inspections during the periodic shutdown. The personnel that I met were knowledgeable and I was content that NGL had a process in place to ensure only 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.
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.