Office for Nuclear Regulation

Torness - Ageing Management inspection

Executive summary

Purpose of Intervention

The purpose of this intervention was to conduct an Ageing Management Inspection of EDF Energy Nuclear Generation Ltd’s (NGL) Torness Power Station. 

This intervention was undertaken as part of a series of planned interventions that are listed in the Torness Integrated Intervention Strategy 2019/2020.

Interventions Carried Out by ONR

An Ageing Management Inspection on the following systems was performed:

B21 Gas Circulators

These systems were identified in a review of the licensee’s safety case, which looked at the systems delivering significant nuclear safety functionality following a depressurisation fault. Through sampling of evidence and a plant walk down of these systems, it was judged that the licensee was compliant with the requirements of LC 28 – examination, inspection, maintenance and testing. 

The focus of the inspection was to establish if the licensee’s arrangements are adequately implemented to detect the onset of equipment degradation, and also to quantify the extant material condition and the rate of ageing of nuclear safety significant plant. Findings from this inspection will be used as part of ONR’s assessment of Torness’s periodic safety review undertaken by the licensee in line with LC15.

Explanation of Judgement if Safety System Not Judged to be Adequate

A system-based inspection was not performed.

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

The inspection sampled licensee’s arrangements for ageing management and their implementation for the systems under consideration. This included plant walk downs to observe the systems, in addition to discussions with various responsible members of EDF NGL staff. Principally, this included system engineers and senior management.

Overall, it was judged that the arrangements for ageing management had been adequately controlled and implemented in line with EDF NGL and ONR expectations.

A number of minor gaps in the station and corporate arrangements were identified however. These were associated with management of uncertainty arising from corrosion under insulation associated with the CO2 Storage and Distribution System and configuration management. Specifically, these were:

CO2 Storage and Distribution System

Component Configuration Management (EDF corporate issue)

These findings were provided as ‘hot feedback’ to the station management at the end of the intervention, along with a number of observations offered for consideration.

Conclusion of Intervention

From the evidence gathered during the ageing management intervention, an intervention rating of green (no formal action) against licence condition 28 was judged to be appropriate.

There were no findings from this inspection that could significantly undermine nuclear safety.  At present, no additional regulatory action is needed over and above the planned interventions at Torness power station as set out in the 2019/20 Integrated Intervention Strategy.

As this was the second operating reactors ageing management inspection, a review, learn, and improve (RLI) study will be carried out to capture any learning and improvement opportunities for subsequent ageing management inspections.