Office for Nuclear Regulation

Reactor 1 Periodic Shutdown 2021 - LC28 compliance inspection for Structural Integrity

Executive summary

Purpose of Intervention

This is a record of an intervention by the Office for Nuclear Regulation (ONR) at Torness Power Station during the 2021 Reactor 1 periodic shutdown. The purpose was to inspect work by the licensee, EDF Energy Nuclear Generation Limited (NGL), to comply with Licence Condition 28 (LC28), examination, inspection, maintenance and testing (EIMT). This activity took place during the periodic shutdown of Reactor 1, which is a requirement of LC30(1).

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.

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

My intervention took place during the Covid19 pandemic. As structural integrity represents a key aspect of the return to service decision and the plant items require visual inspections to check for any signs of degradation, a physical presence on site was necessary.

I took cognisance of the licensee’s arrangements prior to my site intervention and complied with the requirements. The licensee’s arrangements to minimise the risks with Covid19 on site include regular testing, social distancing and staff temperature monitoring using infrared cameras. In my view, these measures appear to be appropriate and efficient. These arrangements appeared to have been correctly followed by plant personnel.

During my intervention, I sampled the structural integrity aspects of the following systems and inspections:

I found satisfactory progress of planned EIMT by the time of my visit, which was approximately half-way through the periodic shutdown programme. Of 282 components in the programme, 86 were not started, 88 in grinding, 1 in progress, 0 in referral, 9 deleted (or replaced) and 107 complete. The scope of these inspections has not been reduced due to Covid19 restrictions.

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 FAC inspections were progressing to programme with no significant issues identified. I obtained an update on progress made at the station in relation to their corrosion management programme. I am encouraged that corrosion inspection and remediation work has continued throughout the current outage.

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 (CP) confirmed that the examinations were proceeding as planned and that station personnel had been providing effective support to their activities. Prior to my intervention, however, NGL reported a shortfall in the PSSR compliance for two low-pressure vessels on the condenser on Reactor 2. Since this reactor is not under its periodic shutdown, I consider this shortfall under a separate workstream. However, in my opinion, PSSR issues appear to add significant demand to NGL’s workload. In my feedback to station, I questioned whether the time allocated to addressing PSSR issues was sufficient to address the current issues and to ensure that long-term compliance is maintained. I will update ONR Regulatory Issue 8462 to reflect the outcome of my intervention. In my site intervention of Reactor 1, however, I did not identify any significant shortfall which would require immediate action.

I met with the System Engineer to discuss progress on inspection activities associated with the Seawater Systems. The inspections were progressing according to plan with no significant issues identified. I undertook a plant walk down, accompanied by the Reactor Sea Water System Engineer. I observed a good standard of housekeeping and have recorded no significant adverse findings as a result of my walk down.

At the time of my intervention, the reactor internal examinations had not yet started due to delays caused by the availability of the fuelling machine. I will monitor progress with the results of these inspections as part of my assessment report. However, during my site intervention, NGL has made me aware of a fault with the Boiler Inspection Manipulator which prevent them from inspecting the boiler components during the periodic shutdown. NGL provided a justification for not carrying out the boiler component inspections during the outage. I will review NGL’s arguments as part of my assessment report of the return to service justification.

Conclusion

Based on evidence sampled, I conclude the licensee is conducting adequate EIMT that should 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.