Office for Nuclear Regulation

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Reactor 7 statutory outage Control and Instrumentation (C&I) inspection

Executive summary

Purpose of Intervention

The purpose of this intervention was to undertake a Licence Condition (LC) 28 compliance inspection at EDF Energy Nuclear Generation Ltd’s (EDF NGL’s) Heysham 2 power station. The main focus of this inspection was to inspect a sample of control and instrumentation (C&I) activities associated with the 2018 statutory outage of Reactor 7 (R7) at Heysham 2, carried out in relation to systems important for nuclear safety, in order to confirm that they remain fit for their intended purpose.

Interventions Carried Out by ONR

The inspection covered by this intervention report was undertaken in support of ONR’s 2018/19 statutory outage inspection programme. The inspection included a sample review of the R7 2018 statutory outage activities carried out in relation to C&I equipment and systems important to nuclear safety. It also covered EDF NGL’s arrangements for compliance with Licence Condition (LC) 28 (Examination, inspection, maintenance and testing - EIMT). The findings of this inspection will contribute to ONR’s regulatory decision to grant Consent to the return of R7 to normal operating service in accordance with LC 30 (Periodic shutdown).

The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.

Explanation of Judgement if Safety System Not Judged to be Adequate

This inspection has generally found that the commitments made in the Outage Intentions Document for the R7 2018 statutory outage (HB/REPS/OM052, Rev 000, TRIM 2017/410973) have been satisfied in relation to the sampled C&I equipment and systems important to nuclear safety.

However, at the time of the inspection, we were informed that the licensee was addressing an issue, identified during the outage related work, regarding the quality of replacement relays in the Essential Plant Protection Equipment (EPPE) system. Given the significance of the EPPE system in terms of maintaining nuclear safety the licensee and ONR agreed that this issue needs to be rectified before the return to service of reactor 7 (R7). ONR and EDF NGL have agreed a plan of engagement to monitor station’s activities to address this issue. A regulatory issue has been raised to monitor its progress. Closure of the associated regulatory issue will enable ONR to recommend granting Consent from a C&I perspective for R7 at Heysham 2 to return to service.

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

During our inspection, we found examples of good ageing and obsolescence management. We also found the plant areas and equipment cubicles we inspected were clean, tidy and free from foreign materials. This provided evidence that good housekeeping practices were being followed. The staff we talked to also demonstrated a good level of knowledge of the systems they were responsible for and an adequate appreciation of the nuclear safety implications of related failures. Examples of good leadership and nuclear safety culture were also apparent from the discussions we had with the recently appointed protection and electrical group head. Based on the discussions during the outage and the sampling of laptops used for maintenance and testing activities on the Data and Processing System DPS, we also noted positive management of cyber security risk.

During the outage inspections, we discussed the station’s plans to address the digital phase failure relays recently identified in some safety related valves in use in R7 Post Trip Sequencing Equipment (PTSE) The station outlined its plan to address the safety related issues before the end of the R7 outage. We considered station’s response to be appropriate and not to impact on ONR’s Consent to allow return to service of R7.

At the time of the inspection not all the R7 outage related C&I work was complete. We identified some areas of interest, the licensee has agreed to provide evidence of the completion of some outage related activities on return to service. In addition, we found a number of minor areas for improvement that were not significant enough to impact on the inspection rating. All these have been captured in an ONR regulatory issue. These aspects do not prevent ONR granting Consent to the return to service of R7 and will be progressed as part of the normal regulatory business.

Conclusion of Intervention

Based on our sample inspection of the C&I aspects of the R7 2018 statutory outage, we found that the station demonstrated the application of good practice in addressing LC28 activities in relation to C&I equipment. Therefore, we have assigned an intervention rating of Green to LC 28 compliance.

However, at the time of the inspection the issue related to the Essential Protection Plant Equipment relay replacement was not resolved. Given its nuclear safety significance ONR and EDF NGL have agreed that this requires adequate resolution prior to R7’s return to service. ONR has raised an ONR regulatory issue to identify the expectation for its resolution. This has been agreed with the licensee and an engagement plan is in place. Closure of this regulatory issue, following suitable and sufficient resolution of the nuclear safety issues associated with the replacement EPPE relays, will enable ONR to recommend granting Consent from a C&I perspective for R7 to return to service.