Office for Nuclear Regulation

Heysham 1 Reactor 1 Graphite Core Inspection Arrangements during the 2020 Statutory Outage

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 A (HYA) power station.

This intervention is one of a number of LC28 compliance inspections performed by ONR during the periodic shutdown of HYA 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 HYA R1 following its 2020 statutory outage.

This intervention specifically focused on arrangements for graphite core examination, inspection and testing and the observations made during these periodic shutdown activities. 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:

Interventions Carried Out by ONR

Due to the current Covid-19 arrangements, a site visit was not conducted. Instead I conducted a remote intervention which was conducted in two parts:

These discussions were held on the 12th and 14th October 2020. For this inspection, I was supported by another ONR Graphite Inspector. My inspection only covered the graphite core inspection activities carried out during the shutdown.

At the time of my intervention, NGL had completed all New In-Core Inspection Equipment (NICIE2) inspections in CO2. As part of the intervention,

This intervention report does not comment on the significance of those findings, which are being addressed by ONR in an assessment of that submission. ONR’s assessment will however take note of the findings of this intervention.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable

Key Findings, Inspector's Opinions and Reasons for Judgements Made

The target requirement for this periodic shutdown is to carry out 21 fuel channel inspections of the bore and one control rod channel inspection. At the time of this intervention, the NGL had completed 14 channel inspections which included visual and bore measurements.

I interviewed a number of personnel who were involved in the graphite core inspections during the periodic shutdown. The personnel that I met appeared knowledgeable and the training records that I sampled were up-to-date. From the training records that I sampled, I consider that the personnel involved in undertaking the graphite core inspections have adequate training and experience to perform their various tasks.

I identified that difficulties in the hand over process due to Covid-19 restrictions caused shortfalls in the capability of the ISI Lead. NGL accepted my point and agreed to review the definition of the ISI Lead role and hand over guidance to identify where improvements could be made. I am content that, at the time of my intervention, the ISI Lead has been managing the graphite inspection activities adequately with support from the wider team.

During my inspection I was content that there was an adequate process in place to ensure procedural compliance and quality of graphite inspections. However, I am aware of processes in place at other stations within the AGR fleet that are, in my opinion, more robust than that observed during my intervention. NGL accepted my advice and stated that they would consult with the wider AGR fleet to determine what learning could be gained.

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 of the reactor core condition.

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.