Office for Nuclear Regulation

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Heysham 1 - Corrosion Management Inspection

Executive summary

Purpose of Intervention

The purpose of this inspection was to review the progress made by the licensee, EDF Energy Nuclear Generation Limited (NGL), in response to a number of actions placed upon Heysham 1 site following a previous site inspection by ONR. This identified shortfalls with the corrosion management programme against the requirements of Licence Condition 28 for the examination, inspection, maintenance and testing of plant important for safety.

These actions were recorded within a regulatory letter (HYA71104R) issued to Heysham 1 requesting an explanation of how the licensee intends to address the shortfalls. Heysham 1 site responded, providing details of the arrangements and improvements that have been implemented to address the shortfalls. This Intervention Record details the judgements and observations made by ONR to review the effectiveness of revised arrangements for managing corrosion under insulation (CUI) of pipework.

I carried out this inspection accompanied by the ONR Heysham 1 site inspector and another Structural Integrity Inspector. The inspection took place on 7 & 8 December 2017 and involved discussions with a number of the licensee's employees responsible for the operation and safety of the plant. A targeted plant walk down of the structures, systems and components for sampling was also undertaken.

This intervention record also captures the findings from the Heysham 1 Annual Review of Safety and Security (ARoSS), which was conducted on the 6 December 2017 attended by the nominated site inspector, security inspector and the ONR delivery leads for operating reactors and civil nuclear security.

Intervention Carried Out by ONR

This inspection reviewed Heysham 1's revised arrangements for prioritising, sentencing and recording the decisions and judgements made for remediating CUI on pipework. This inspection reviewed the adequacy of the site forward action plan to progress the remediation of both historic and ongoing Category 2 defects on systems with a safety significance, so as to demonstrate that they are being managed in a timely manner

ONR also assessed the adequacy of the licensee's arrangements to ensure effective and sustainable oversight of the corrosion management process, to ensuring that staff changes involving key members of the corrosion management programme are managed with minimal negative impact to the inspection or remediation programme.

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

From the information that I have sampled during this inspection regarding the Heysham 1 site corrosion management programme, I consider that the licensee has provided a suitable demonstration of the processes, tools and procedures implemented to address the shortfalls identified during the previous site visit, as recorded in regulatory letter HYA71104R.

In my opinion, the licensee has shown that there is an effective process in place for prioritising, sentencing and remediating CUI on pipework, and has been able to demonstrate that decisions and judgements made to support the proposed prioritisation of inspections and remedial actions are appropriately recorded.

I am satisfied that the licensee has developed a suitable forward action plan and has embedded sufficient resource to progress the remediation of both historic and ongoing Category 2 defects on systems with a safety significance, in a timely manner.

Since my last visit, the licensee has revised the site oversight arrangements for the corrosion management process. I have reviewed these changes, which I judge to be effective and sustainable such that any future staff changes, involving key members of the corrosion management programme, are likely to be managed with minimal negative impact to the inspection and remediation work that is in progress.

Conclusion of Intervention

In my opinion, Heysham 1 has made significant progress with improving their understanding of plant material condition and has a structured, well-managed process in place for identifying those systems most at risk from CUI, based on their safety significance. I am satisfied that the licensee has a robust set of management tools and procedures in place to address the shortfalls previously identified.

From the information I have sampled during this intervention, I judge that the arrangements demonstrated by the licensee for the management of CUI on pipework at Heysham 1 against the requirements of LC28 currently conform to a GREEN rating, with no formal action necessary.

At the Annual Review of Safety and Security, the station provided a comprehensive review of safety over the past 12 months and the key challenges and safety/ security improvements implemented over that period as well as a forward look. The station director also explained the two main focus areas for the station business plan over the next three years. ONR acknowledged the safety and security improvements which have been implemented on the station.

Recommendations

With regards to the corrosion management programme, I am satisfied that the licensee has provided sufficient information to address the final outstanding action presented in issue 4840, as recorded on the ONR regulatory issues database, such that the licensee has suitably demonstrated that they have developed a forward action plan with associated completion timescales for those systems where inspections are still ongoing (including CV 2, 3 and 4 systems). Whilst improvements have been made, I recognise that Heysham 1 is still managing corrosion with an enhanced level of targeted resource and central engineering function oversight. I therefore consider it necessary to maintain regulatory oversight of the progress of the corrosion management programme at Heysham 1 through ONR's normal regulatory business. I anticipate this to remain at a level of attention that is commensurate with the fleetwide management of corrosion, until the scope of inspection and remediation work has been accepted and endorsed as being managed through normal EIMT activities.

I therefore make the following recommendations:

Recommendation 1: Issue 4840 should be presented to the ONR Operating Reactors Sub-division board, along with the evidence presented within this intervention record, for consideration for closure.

Recommendation 2: ONR should continue to monitor the corrosion management process at Heysham 1 via its routine engagement with station during Periodic Shutdowns and System Based Inspections, as appropriate.