Office for Nuclear Regulation

SBI 12 Fuelling Machine and Decay Store

Executive summary

Purpose of Intervention

This intervention was to undertake a compliance inspection at EDF Energy Nuclear Generation Limited’s Torness power station, forming part of the ONRs Torness Integrated Intervention Strategy (IIS) for 2018/19.

Interventions Carried Out by ONR

I, the ONR nominated site inspector, together with specialist control & instrumentation (C&I) and mechanical engineering inspectors, conducted a Systems Based Inspection (SBI) of the fuelling machine (FM) and decay store, to judge the system’s performance against its safety function.  In this case, as the decay store has been the subject of a recent inspection, it was decided to focus this intervention on the Fuelling Machine.

The inspection sampled the implementation of the licensee’s arrangements at Torness against six license conditions (LCs).  The objective of the inspection was to determine whether the licensee’s arrangements were adequately implemented and in accordance with the system’s safety case requirements.  The LCs were:

The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.

Explanation of Judgement if Safety System Not Judged to be Adequate

On the basis of our sample I consider safety systems to be adequate.

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

In general we found on the basis of our sample that Torness has adequate arrangements in place to ensure that the Fuelling Machine is operated inspected and maintained by trained staff in accordance with the safety case.

We found that there was a good link between claims in the safety case, operating rules and working instructions for staff. The sample of staff we selected appeared to be adequately trained for their role, and there is a new system that provides up to date information on competence for team leaders, although we found technical problems with this that will need to be resolved. This was a minor observation and I was therefore content for the station to follow this up itself.

The licensee has self-identified, that it would be helpful if some of the records produced following measurements, inspections and tests carried out under LC28 were more specific. We noted that relays on some of the Fuelling Machine protection systems have been in place for thirty years, and although they are given regular functional tests we requested that the Station consider how their ageing and obsolescence may affect maintenance plans. In light of this observation, I have elected to raise a regulatory issue to follow the station’s progress of it. On the whole though we considered examination, maintenance and testing met its legal duties.

We therefore gave a rating of ‘Green – no formal action’ against each of the license conditions.

Conclusion of Inspection

After considering all the evidence examined during our sample inspections, undertaken against LCs 10, 23, 24, 27, 28 and 34 we judged that the fuelling machine met the requirements of the safety case. This was communicated to Station management at the close of the inspection.

We agreed a number of points where we would like further clarification to be provided, and there was one new regulatory issue concerning ageing and obsolescence of protection systems which as such will be followed through to closure.

There were no findings from this inspection that could significantly undermine nuclear safety.  At present, no additional regulatory action is needed over and above the planned interventions of Torness nuclear power station as set out in the Integrated Intervention Strategy, which will continue as planned.