Office for Nuclear Regulation

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Sizewell B - Outage and Periodic Shutdown - Electrical Aspects

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 Limited (NGL) Sizewell B Power Station, in line with the inspection programme contained in the Sizewell B Integrated Intervention Strategy (IIS) for 2017/18.

Interventions Carried Out by ONR

I undertook a planned inspection and assessment of implementation of the arrangements for LC 28 Examination, Inspection, Maintenance and Testing (EIMT) at Sizewell B Power Station.

The inspection sample targeted the planned electrical work being undertaken as part of the refuelling outage 15, 2017 statutory outage and Periodic Shutdown, including the planned electrical EIMT activities from the station's outage intentions document, the implementation of the detailed modifications and any reactive electrical work emergent from the shutdown.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable.

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

My discussions with the licensee and its explanations to my questions I was satisfied with the station's responses. One minor shortfall was identified with the implementation of the established arrangements for LC 28 EIMT in relation to the planned electrical work being undertaken, to which Station has satisfactorily responded. I was satisfied with the station's immediate response and plans to prevent recurrence. I was also satisfied that this finding, the immediate response and plan to prevent recurrence would not prevent ONR from granting a return to service. I have raised a regulatory issue in order to monitor the station's plans to prevent recurrence. My targeted inspection confirmed that the planned EIMT and modification activities during this periodic shutdown were appropriate and that electrical plant and equipment that was being maintained was in accordance with the licensee's arrangements.

Overall, the outcome from the safety inspection of the shutdown related electrical activities for the refuelling outage 15, 2017 statutory outage and periodic shutdown was that the implementation of the LC 28 arrangements for the electrical equipment was found to be adequate; therefore a green inspection rating was awarded.

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

Conclusion of Intervention

From the sample inspected, it is judged that for the electrical work activities undertaken at Sizewell B during the refuelling outage 15, 2017 statutory outage and periodic shutdown, compliance against LC28 met the required standard, I have therefore rated this compliance inspection as ‘Green' rating .

Based on these targeted interventions there were no other issues identified from the electrical work activities which would prevent ONR granting Consent for Sizewell B to return to service from the refuelling outage 15, 2017 statutory outage and periodic shutdown. This is subject to the completion of the planned EIMT activities, the implementation of the detailed modifications and the completion of emergent electrical work. Station has been informed of this condition and has committed to keep ONR informed of any proposals to defer planned electrical EMIT activities or any emergent electrical issues

From the evidence gathered during this intervention, there were no matters identified that have the potential to impact significantly on nuclear safety.