Office for Nuclear Regulation

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Hartlepool Power Station - Reactor 1 Outage 2014 - Civil Engineering Inspection

Executive summary

Purpose of intervention

The purpose of the site visit was to discuss and witness a sample of the statutory surveillances, inspections and tests to be undertaken by EdF Nuclear Generation (NGL) on Reactor 1 pre-stressed concrete pressure vessel (PCPV) at Hartlepool Power Station.  This intervention is to provide support to ONR’s response to NGL’s anticipated request for consent for return service following the 2014 periodic shutdown.

Interventions Carried Out by ONR

This was a site inspection visit to witness some of the pre-stressed concrete pressure vessel surveillances and inspections to assess compliance with Licence Condition 28.

Explanation of Judgement if Safety System Not Judged to be Adequate

N/A.

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

I witnessed the re-stress of one of the tendons from the soffit end and the leak sealing works in tendon CCA5.  

In the inner soffit inspection, I inspected the deposits in the CO2 penetrations, in particular quadrant 1D2. I highlighted to the Appointed Examiner (APEX) the importance of identifying new water leaks in these penetrations.

I discussed with the APEX the feasibility of thickness checks on the tendon’s bearing plates. He confirmed that the Licensee will include thickness checks in future inspections.

The APEX has recorded the condition of all the vertical tendon Hot Gas Release (HGR) shroud valves in the inner soffit tendons, as an alternative way to identify Pressure Vessel Cooling Water leaks. This visual examination exceeds the minimum Maintenance Schedule requirements for vertical tendon HGR valves.

I discussed the PCPV inner bearing inspections with the APEX and agreed to consider the inspections again after those at the sister station, Heysham A, have been conducted. The Heysham A PCPV inner bearings are easier to access and these inspections will provide key learning points prior to further Hartlepool PCPV inner bearing inspections.

I inspected octant DA at the pile cap and no signs of water where found.  I suggested NGL continue to monitor this area.

I visited the tendon storage building and I inspected the condition of the tendons withdrawn, CDD1 and ABD2.  Both tendons were in good condition with only some minor signs of surface corrosion.

Conclusion of Intervention

I conclude from the site inspection that the statutory surveillances, inspections and tests, along with the additional tendon probe inspections are proceeding as normal. There are no findings that could challenge return to service.

The arrangements on site meet the requirements in the Maintenance Schedule and in some cases exceed them. There is a clear drive to identify the condition of all the wetted tendons and to replace those which have a history of wetting. There are some known areas for improvement, but they will be addressed in future outages. I judge the overall site inspection as adequate and I assign an IIS rating of Adequate, 3.