Office for Nuclear Regulation

Hunterston B - LC28 planned electrical inspection

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) Hunterston B Power Station, in line with the inspection programme contained in the Hunterston B Integrated Intervention Strategy (IIS) for 2018/19.

Interventions Carried Out by ONR

We undertook a planned inspection of implementation of the arrangements for LC 28 Examination, inspection, maintenance and testing (EIMT) at Hunterston B Power Station.

The inspection sample targeted the planned electrical work being undertaken as part of the Reactor 3 and Turbo Generator (TG) 7 2019 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

Based on the discussions, explanations and the sample inspected, on this occasion, we were satisfied that there were no significant shortfalls identified with the implementation of the established arrangements for LC 28 EIMT in relation to the planned electrical work undertaken as part of the Reactor 3 and TG 7 2019 periodic shutdown. The targeted inspection undertaken confirmed that the planned EIMT activities during this shutdown were appropriate and that electrical plant and equipment that was being maintained was in accordance with the established arrangements.

We identified, however, that there was an absence of appropriate pass/fail criteria on a number of maintenance documents sampled. Whilst the results recorded on the maintenance documents were confirmed as being acceptable, we judged that appropriate pass/fail criteria should be present to confirm that results are acceptable or if unacceptable invoke an appropriate review. Therefore, regulatory issue 7107 was raised to monitor and manage the update of the affected maintenance documentation.

Notwithstanding this minor shortfall identified,  the outcome from the safety inspection of the shutdown related electrical activities for the Reactor 3 and TG 7 2019 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 Hunterston B during the Reactor 3 and TG 7 2019 periodic shutdown, compliance against LC28 met the required standard, therefore a ‘Green’ rating was given.

Based on the targeted interventions there were no issues identified from the electrical work activities that would prevent ONR granting Consent for Reactor 3 and TG7 to return to service. This is subject to the completion of the planned EIMT activities, the implementation of modifications and the completion of emergent electrical work.

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