Office for Nuclear Regulation

System Based Inspection – SBI 08 – Short Break Electrical Supplies

Executive summary

Purpose of intervention

The purpose of this intervention was to conduct a system based inspection at EDF Energy Nuclear Generation Limited’s Torness Power Station in accordance with the planned inspection programme contained in the Torness Integrated Intervention Strategy (IIS) for 2015/16.

This intervention was undertaken by an ONR Electrical Specialist Inspector and by the   Nominated Site Inspector for Torness.

Interventions Carried Out by ONR

As part of this intervention, the ONR Electrical Specialist Inspector and I (Nominated Site Inspector, Torness) performed a System Based Inspection (SBI) of the Short Break Electrical Supplies system to judge the system performance against its safety function.  Through examination of this system and associated sub-systems we performed compliance inspections against Licence Conditions:

The inspections were based on sampling the implementation of the arrangements in place against each licence condition.

Explanation of Judgement if Safety System Not Judged to be Adequate

From the inspection, we judge that overall the Short Break Electrical Supplies system meets the requirements of the safety case and is adequate.

Key Findings, Inspectors’ Opinions and Reasons for Judgements Made

Based on the areas sampled during the course of the system inspection, it was found that Torness has adequate arrangements in place to ensure that the Short Break Electrical Supplies system is maintained and operated in accordance with the safety case and the station’s arrangements.  The inspection identified a specific shortfall in one of the station’s operating instructions which has been raised as an ONR issue.  In addition a number of minor maintenance concerns were also noted.  All of these have been accepted by the station who have raised Condition Reports (CR) or Work Requests (WR) as appropriate to undertake corrective action within their arrangements.

In summary, the outcome from the SBI of the Short Break Electrical Supplies system is that the system adequately fulfils the requirements of the safety case.  Ratings for the Licence Conditions are as follows:

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

After considering all the evidence examined during the sample inspections undertaken against LCs 10, 23, 24, 27 and 28, we considered that the Short Break Electrical Supplies system met the requirements of the safety case.  LC34 was not applicable to this system.

Although a small number of minor issues were identified, there are no findings from this inspection that could significantly undermine nuclear safety or which would result in changes to the planned interventions and inspections of Torness Power Station.  ONR will pursue the minor issues as part of normal business.