Office for Nuclear Regulation

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Sizewell B Refuelling Outage 14 Electrical Inspection

Executive summary

Purpose of intervention

This report covers an inspection at EDF Energy Nuclear Generation Limited's Sizewell B power station, which was one of a series of planned interventions during the RO14 (Refuelling Outage 14) periodic shutdown.

Interventions Carried Out by ONR

The inspection considered electrical work activities being undertaken as part of the RO 14 periodic shutdown and progress with addressing actions from previous inspections. The inspection of RO14 work activities covered electrical works specified in the Outage Intentions Document (OID) and any related emergent work.

As part of this intervention, ONR carried out compliance inspections against the requirements of Licence Condition (LC) 28, 'Examination, inspection, maintenance and testing'.

Explanation of Judgement if Safety System Not Judged to be Adequate

This inspection was not a safety system inspection, and therefore this section is not applicable.

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

In respect of the outage work activities, I am satisfied that electrical work activities are progressing to schedule, with no significant issues identified during the inspection. Furthermore, I received assurances from station that all planned activities were on schedule to be completed before the reactor is returned to service.

The inspection identified a few areas for potential improvement, and although none of these gave rise to significant concern, station accepted actions to implement improvements.

A minor deficiency relating to a partially-addressed action from a previous electrical inspection was identified during a plant walk-down. The licensee agreed to address this conventional safety matter within defined timescales.

A sample review of outage electrical maintenance records also highlighted some minor discrepancies between the specified and actual sequence in which steps of the work procedure were applied. Whilst it is considered this did not affect completion of the activity, the licensee agreed to review the maintenance procedure.

Conclusion of Intervention

From the information gathered and evidence obtained during this intervention, I am content with the progress the licensee is making with their electrical power LC30 activities as part of the outage. I consider that the licensee is delivering against its planned outage activities and as a result consider that an IIS Rating of Green is appropriate.

Although, a small number of issues have been identified in the way maintenance work is instructed and recorded, I consider that these are minor and an IIS Rating of Green is appropriate in respect of LC28 compliance

In summary, in respect of the safety related electrical engineering work, I have not identified any issues of significance that should prevent ONR from granting Consent for Sizewell B Reactor to restart and operate for a further period.