Office for Nuclear Regulation

Graphite Inspection Activities for the Torness 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) 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 2021 periodic shutdown, as required by LC30(1).

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 10th and 16th February 2021. 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 14 out of 30 New In-Core Inspection Equipment (NICIE2) inspections. As part of the intervention,

We examined some of the visual records to form an ONR view as to the quality and adequacy of the data being recorded;

We reviewed the training records and their administrative arrangements to ensure the adequacy of the graphite core inspections;

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

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 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.

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.