Office for Nuclear Regulation

LC 28 Inspection of Electrical related aspects

Executive summary

Purpose of Intervention

The primary focus of this intervention was to undertake a Licence Condition (LC) 28 compliance inspection during the 2018 periodic shutdown of Reactor 2 (R2) at Torness power station.

The main focus of the inspection was to judge the adequacy of the electrical engineering activities being carried out during the outage by EDF Energy Nuclear Generation Ltd (EDF Energy NGL), the licensee responsible for the Torness (TOR) power station. 

The inspection was carried out by two ONR electrical specialist inspectors, in line with the planned inspection programme contained in the intervention strategy for the Operating Facilities Division (OFD) of the Office for Nuclear Regulation (ONR).

Interventions Carried Out by ONR

ONR undertook a one day planned inspection and assessment of the implementation of arrangements for LC 28 (Examination, inspection, maintenance and testing - EIMT) at Torness Power Station.

The inspection sample targeted the planned electrical work being undertaken as part of the R2 2018 periodic shutdown, including the planned electrical EIMT activities from the station’s outage intentions document and reactive electrical work emergent from the shutdown. Our inspection contributes towards ONR’s regulatory decision whether to grant Consent, to the return of R2 at Torness to normal operating service, in accordance with LC30 (Periodic shutdown).

The following principal ONR guidance was utilised to perform the inspection:

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

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 LC28 EIMT in relation to the planned electrical work undertaken as part of the Torness power station R2 2018 periodic shutdown. The targeted inspection undertaken confirmed that the planned EIMT and modification activities during this shutdown were appropriate and that electrical plant and equipment that was being maintained and modified in accordance with the established arrangements. 

The inspection, however, identified one area for potential improvement regarding the acceptance criteria for insulation resistance checks. Although this did not gave rise to significant concern, the station has agreed to take action to address this concern. I have therefore raised a new level 4 regulatory issue to provide proportionate regulatory oversight of this matter. Notwithstanding this finding, overall, the outcome from the safety inspection of the electrical activities for the Torness power station R2 2018 periodic shutdown was that the implementation of the LC 28 arrangements for the electrical equipment was found to be adequate when judged against relevant good practice expectations.

Conclusion of Intervention

From the sample inspected, it is judged that for the electrical work activities undertaken at Torness power station during the R2 2018 periodic shutdown, compliance against LC28 met the required standard; we have therefore rated this compliance inspection as ‘Green’ (no formal action required).

One finding related to the need to review the acceptance criteria for insulation resistance checks. I therefore raised a Level 4 Regulatory issue to provide regulatory oversight of the review (and if needed revision) of the relevant instructions.

There are no findings from this inspection that could significantly undermine nuclear safety.  No additional regulatory action is needed over and above ONR’s planned Torness interventions as set out in our Integrated Intervention Strategy.

Based on these targeted interventions there were no other issues identified from the electrical work activities which would prevent ONR granting Consent for Torness to return to service from the current outage and periodic shutdown. This is subject to the completion of the planned EIMT activities, the implementation of the planned modifications and the completion of emergent electrical work. The station’s Protection and Electrical Engineering Group Head 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.