Office for Nuclear Regulation

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Heysham 2 – Structural Integrity Inspection

Executive summary

Purpose of Intervention

This is a record of an intervention by the Office for Nuclear Regulation (ONR) at Heysham 2 Power Station (HYB) during the 2018 Reactor 7 (R7) periodic shutdown. The purpose was to inspect work by the licensee, EDF Energy Nuclear Generation Limited, to comply with Licence Condition 28 (LC28), examination, inspection, maintenance and testing (EIMT).

Interventions Carried Out by ONR

I met with licensee staff and their contractors to examine compliance with Licence Condition 28. I concentrated on aspects of structural integrity that I judged important to nuclear safety.

I sampled aspects of the inspection programme undertaken during the periodic shutdown on the steam and feed systems and other safety related systems external to the reactor pressure vessel. NGL are conducting vessel entry at this shutdown to perform a planned repair and to conduct inspections and sampling of boiler components as part of its High Temperature Behaviour of Austenitic Stainless Steel (HTBASS) project. ONR has previously engaged with NGL on this matter on several occasions and is aware of their plans. The vessel entry activities had not commenced by the date of our inspection.

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

I found satisfactory progress of planned EIMT by the time of my visit, which was day 34 out of a 67 day shutdown. Of 297 components in the programme, 52 were not started, 97 in grinding, 9 in progress, 2 in referral, 1 repaired and 137 complete.
I have of sampled aspects of the following:

I sampled the inspection work that had been undertaken as part of the reactor external inspection programme, reviewing inspections completed and associated results. I was content that the work was progressing effectively, with inspection results sentenced appropriately. Weld and Flow Accelerated Corrosion (FAC) inspections were progressing to programme with no significant issues identified.

I viewed digital images from inspections of several reactor internal components. I consider that due process was being followed. No issues that could affect the planned work were apparent and no significant findings have been reported relating to the internal inspections to date.

I sampled the operation of the HYB’s Outage Assessment Panel (OAP) during my visit and by reviewing OAP minutes. I was satisfied that the OAP was following due process and that the inspection results were being reviewed appropriately.

I obtained an update on progress made at HYB in relation to their corrosion management programme. I am encouraged that corrosion inspection and remediation work has continued throughout the current outage.

I undertook a plant walk down, accompanied by the OAP Chair and INSA Engineer. I observed a good standard of housekeeping and have recorded no significant adverse findings as a result of my walk down.

I met with the System Engineer to discuss progress on inspection activities associated with the Essential Cooling Water Systems. The inspections were progressing according to plan with no significant issues identified.

I discussed progress on examinations and inspections undertaken during the periodic shutdown, as required by the Pressure Systems Safety Regulations (PSSR). The PSSR Competent Person confirmed that his examinations were proceeding as planned and that station personnel had been providing effective support to his activities. One anomaly was identified within a Written Scheme of Examination (WSE) for the boiler start up vessel. As a result, the PSSR Advisor has committed to reviewing all WSEs to ensure they are suitable.  I judge this to be an acceptable position.

As the planned vessel entry programme had not commenced by the date of my inspection, ONR has arranged regular, twice weekly telecoms with NGL in order to remain aware of any developments during the vessel entry campaign.

Conclusion

Based on evidence sampled, I conclude the licensee has performed adequate EIMT to satisfy LC28. I consider that an inspection rating of green is appropriate, based on ONR guidance.

EIMT work planned by the licensee during the periodic shutdown was not complete by the end of my inspection. I will monitor further progress and provide my judgement regarding return to service in my assessment report.