Office for Nuclear Regulation

Electrical Outage Inspection

Executive summary

Purpose of intervention

This report covers an inspection at EDF Energy Nuclear Generation Limited's (NGL) Dungeness B site. The inspection considered the electrical activities undertaken as part of the 2014 Major Outage on Reactor 21 as well as a review of progress in addressing actions raised in response to previous ONR electrical inspections.

Interventions Carried Out by ONR

As part of this intervention, I carried out compliance inspections against Licence Condition (LC) 28, 'Examination, Inspection, Maintenance and Testing'.

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

Not applicable.

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

In respect of the outage, the majority of routine maintenance activities have now been completed with no significant issues identified. The refurbishment of key transformers and associated isolated phase busbars is ongoing although no issues are expected. In addition, the remaining maintenance activities are routine, again with no expectation of issues. A review of a sample of the maintenance paperwork associated with activities showed that the activities had been completed and correctly signed off.

I confirmed that EDF Energy NGL had addressed all the actions I had raised at previous electrical interventions and they were all satisfactorily closed.

I discussed plant degradation and obsolescence issues with the station and I consider that they have adequately considered lifetime management of the critical electrical components.

In respect of the site walkdown, the condition of the site was generally good with only a few defect tags, all of a minor nature, observed.

Conclusion of Intervention

I am content with the progress the licensee is making with their electrical power LC28 activities in support of the outage. I consider that the licensee is delivering against its planned outage activities and taking appropriate proactive action in relation to lifetime issues. As a result, I consider that an IIS Rating of 3 is appropriate in this case.