Office for Nuclear Regulation

This website uses non-intrusive cookies to improve your user experience. You can visit our cookie privacy page for more information.

Heysham 2 - R8 Periodic Shutdown - Structural Integrity Inspection

Executive summary

Purpose of Intervention

This report records the findings of an intervention visit to the Heysham 2 Nuclear Power Station during the 2016 Reactor 8 periodic shutdown. The intervention was undertaken to confirm the adequacy of the work conducted by the licensee, EDF Energy Nuclear Generation Limited (NGL), to comply with the requirements of Licence Condition 28, examination, inspection, maintenance and testing.

Interventions Carried Out by ONR

I undertook on-site meetings and plant inspections with relevant staff from the licensee to determine the adequacy of the work being undertaken on Reactor 8 in complying with the requirements of Licence Condition 28. I concentrated my intervention on items I judged important to nuclear safety, focussed on structural integrity.

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. I also sampled aspects of the inspection programme undertaken on the metallic components internal to the reactor pressure vessel.

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

I visited site approximately a third of the way through the periodic shutdown, according to the licensee’s programme. The status of the inspections highlighted satisfactory progress on the reactor external inspection programme, with 204 out of the 373 inspections completed at the time of my inspection.

I sampled the inspection work that had been undertaken as part of the reactor external inspection programme, looking at both the inspection work itself and the categorisation of the results, and was satisfied with what I found.

I sampled the operation of the licensee's outage assessment panel (OAP) during my visit, by observing an OAP meeting. The OAP meets to review the inspection work undertaken during the periodic shutdown and sentences the inspection findings. I was satisfied that the OAP was following due process and that the inspection items raised were sentenced appropriately.

I undertook a plant walk down during my visit, escorted by the OAP Chair. The licensee’s site staff were able to provide satisfactory explanations of both the operation of the systems and the inspection/maintenance of the systems planned or already performed during the periodic shutdown.

Due to staff unavailability I was unable to spend time with the reactor internals ISI co-ordinator, therefore I agreed on a selection of components to sample prior to the inspection, which I will assess in my assessment report, prior to return to service.

I discussed progress on inspection, maintenance and testing activities associated with the seawater system. The work programme was progressing according to plan, with the bulk of the inspections completed 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). No significant issues have been identified as a result of the inspections completed so far, however, on receipt of the sampled written scheme of examination and inspection report, there were obvious minor errors. I reported this to the PSSR co-ordinator in the debrief and advised me that he will investigate and rectify the issue.

I discussed progress on the steam and feed pipework hanger survey. The pre-outage hot hanger and post-trip cold hanger survey were complete and reported. The majority of remedial actions had been complete. Following the Return to Service (RTS), a post-outage hot survey will be performed.

A section of structural steel failed in one of the quadrants where outage activities were being performed. This structural steel supports a small section of main steam pipework and therefore, during our inspection, I discussed the details of the remedial work. Although there is still some work to be done in dealing with this issue and understanding the root cause, I am satisfied with the steps taken by site to address the event.

Conclusion of Intervention

I judge that, at the time of my visit to Heysham 2 nuclear power station, personnel were conducting their inspections in line with the pre-outage intentions documentation and associated inspection specifications. The inspections conducted so far have not raised any nuclear safety significant issues of concern and the licensee appears to be adequately managing any defects or anomalies identified. I will use the minutes from the remaining OAPs to monitor for any emerging issues from the inspections that have yet to be completed and report on this in my structural integrity assessment report on the return to service of Heysham 2 Reactor 8 following its 2016 periodic shutdown.

A number of emergent issues have been identified by the licensee during my inspection which will be assessed as part of the structural integrity assessment report or project assessment report supporting the LC30 consent for return to service of Heysham 2 Reactor 8 following the 2016 periodic shutdown.

From the information that I have sampled during my inspection, I judge that, from a structural integrity perspective, the licensee has performed the examination, inspection, maintenance and testing work to an adequate standard against the requirements of LC28. At the time of my visit, and from my sample inspections, I found nothing that in my opinion would prevent Heysham 2 Reactor 8 returning to service following completion of the 2016 periodic shutdown. I consider that a Green rating is appropriate for this inspection, warranting no formal actions.