Office for Nuclear Regulation

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Phase 2 Visit to Heyshsam 1 Power Station as Part of the Corrosion Under Insulation Concealed Systems Intervention

Executive summary

Purpose of intervention

The purpose of this intervention was to conduct a benchmark inspection of the arrangements in place at Heysham 1 power station (HYA) to manage the integrity of concealed pipework, with an emphasis placed upon how corrosion is managed.

I carried out this inspection accompanied by another ONR Structural Integrity Inspector and the ONR Nominated Site Inspector. The inspection took place from the 4 to the 5 October 2016 and involved discussions with a sample of EDF Nuclear Generation Limited's (NGL's) employees responsible for the operation and safety of the plant. A plant walk down was also undertaken.

At the time of my inspection, a Health and Safety Executive (HSE) inspector was conducting an inspection of the licensee's arrangements for managing compliance with the Control of Major Accidents and Hazards (COMAH) regulations at HYA site. The scope, conclusions and judgements from this inspection are presented in a separate report which is outside of the scope of my inspection.

Interventions Carried Out by ONR

The objective of the inspection was to obtain information relating to the licensee's arrangements for managing corrosion of their concealed pipework, in order to identify any areas of positive operational experience, or shortfalls against our expectations. I concentrated my intervention on items I judged important to nuclear safety, focussed upon structural integrity.

My inspection reviewed the strategy, arrangements, procedures and roles and responsibilities of staff associated with the licensee's corrosion management programme. I sampled compliance arrangements against licence condition (LC) 28 (examination, maintenance, inspection and testing) to judge the adequacy of the arrangements in place.

Explanation of Judgement if Safety System Not Judged to be Adequate

No safety system inspection was undertaken, hence this is not applicable.

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

From the information I have sampled and discussions with station staff, I am generally satisfied that the process used at HYA to identify and inspect pipework corrosion on systems important for safety meets relevant good practice and follows a scope established in accordance with the licensee's LC28 arrangements for corrosion and ageing management.

Whilst my inspection noted that the progress of the corrosion management programme at HYA site is ongoing, I am satisfied from the higher priority remediation work already in progress that the station is making adequate progress. In order to monitor this progress, ONR Issue 4840 has been raised on the licensee to provide a programme and scope of works for completing the lower-priority inspections, and how they intend to implement and effectively prioritise remediation of corrosion related defects at HYA.

From the discussions that I have held with the managers and engineers at HYA site, I am satisfied that they have demonstrated an adequate level of corrosion awareness and an understanding of the contributing factors and prevention of Corrosion Under Insulation (CUI). I judge that, from the perspective of corrosion awareness, HYA has implemented adequate arrangements for training those on site that have responsibility for pipework affecting safety. I consider the approach taken by the Corrosion Coordinator to set up an internal network of corrosion leads within each of the major operating groups on site team to be an example of maintaining good oversight of inspection progress and the management of corrosion issues identified.

In my opinion from the information I have sampled, the licensee has demonstrated that adequate arrangements are in place for the regular and systematic examination, inspection maintenance and testing of the pipework contained with the Secondary Shutdown and Emergency Generation systems, and hence a rating of green will be recorded against LC28.

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

I judged that the arrangements at HYA and their implementation, associated with concealed pipework and corrosion under insulation generally meet relevant good practice and a green rating will be recorded against LC28. Although areas for improvement have been identified, it is acknowledged that the licensee is introducing measures to address them. Consequently ONR issue 4840 has been raised for the station to provide a programme and scope of works for completing the lower-priority inspections, and how they intend to implement and effectively prioritise remediation of corrosion related defects at HYA.

From the evidence gathered during this intervention, I do not consider there to be any matters that have the potential to impact significantly on nuclear safety.

At present, no additional regulatory action is needed over and above the planned interventions of Heysham 1 power station as set out in the Integrated Intervention Strategy, which will continue as planned.