Office for Nuclear Regulation

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Dungeness B - Reactor 21 (R21) control and instrumentation (C&I) statutory outage inspection date

Executive summary

Purpose of intervention

This intervention report covers my control and instrumentation (C&I) inspection performed as a part of an ONR civil nuclear reactor programme (CNRP) intervention applicable to EDF Nuclear Generation Ltd (EDFNGL) during the outage of Reactor 21 (R21) at Dungeness (DNB) Power Station. The main focus of my inspection was to verify that relevant work activities have been carried out in relation to C&I equipment and systems important to safety in order to confirm that this remains fit for its intended purpose at DNB.

Interventions Carried Out by ONR

My inspection was made in support of ONR's 2013/14 Statutory Outage inspection programme. The outcome of my inspection, which included a review of progress made in various work items and projects associated with C&I equipment and systems important to safety at DNB, covered EDFNGL's arrangements under Licence Conditions 28 (Examination, inspection, maintenance and testing). This is intended to provide a contribution towards ONR's regulatory decision as to whether a Consent in accordance with LC30 (Periodic shutdown) should be issued to allow R21 at DNB to return to normal operating service.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable.

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

I raised four actions relating to emergent work. These actions are described in section 3 of this report. Three of the actions do not require resolution prior to return to service of R21 and will be monitored during future C&I specialist intervention inspections at DNB. The fourth action relates to the four neutron flux detectors (NFDs) used at DNB in the measurement of reactor power upon reactor start-up. I have stipulated that EDFNGL ensure testing is complete and technically reviewed demonstrating the four pulse NFDs continue to fulfil their specified functionality. I have received assurance from the station that the evidence will be provided in full, or the proposed way forward will be recorded under that station's outage arrangements and agreed with ONR.

Based on these findings I have assigned an integrated intervention strategy (IIS) rating of 3 (adequate) to LC 28.

Conclusion of Intervention

On the basis of my inspection of the C&I aspects of the DNB R21 outage, I recommend that support be given for a Consent to allow R21 at DNB to return to normal operating service.