Office for Nuclear Regulation

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Wylfa Power Station - IIS Inspection

Executive summary

Purpose of intervention

This report covers the nuclear safety related inspection of Wylfa power station undertaken as part of a series of interventions including those listed in the Integrated Intervention Strategy (IIS) plan, inspections deemed necessary to cover emergent work, and follow-up of matters carried forward from previous visits.

Interventions Carried Out by ONR

This intervention included planned compliance inspections against the following Licence Conditions (LCs):

Other matters of a routine nature that are deemed unlikely to have a significant effect on nuclear safety, and which are being addressed routinely under the licensee's arrangements, were also covered during the inspections.

Explanation of Judgement if Safety System Not Judged to be Adequate

No system based inspections were conducted during this intervention visit.

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

An inspection was carried out of the arrangements, and their implementation, to comply with LC 30 concerning periodic shutdown of reactor 1 to allow examination, inspection, maintenance and testing (EIMT) of plant which may affect safety. During the inspection a sample of the site licence compliance arrangements documents for LC30 and LC28 were examined, and were deemed to be satisfactory overall. The inspection also confirmed that the arrangements have been updated, following a previous ONR inspection of this topic. On the basis of the areas sampled during the inspection, I have given this component of my inspection a rating 3 (adequate).

An inspection was carried out of the arrangements to comply with LCs32&34 relating to accumulation of radioactive waste and, leakage and escape of radioactive material and waste, at Wylfa power station. The inspection confirmed that station is taking steps to improve the arrangements for LCs32&34, and their implementation, following the ONR specialist inspection in March 2013. Examination of the station action response programme confirmed that progress is being made to address the findings from the inspection, including any emergent work that has been identified. While work remains to be done, the improvements put in place at this stage, together with the station commitment to complete the improvement programme to time, has led me to award an inspection rating 3 (adequate) to this work.

An inspection was carried out of the arrangements to comply with LC 22 relating to modifications to existing plant on the Wylfa power station site. The inspection confirmed that Station has made and implemented arrangements to control modifications carried out on the existing plant that were deemed to be satisfactory overall. However, an area for improvement was identified during the inspection relating to the contents of a supporting arrangements document, and they have agreed to take action to address the finding. In addition, they have taken steps to improve control of open modifications on the plant, and to close modifications that have remained open after completion of the work. Therefore, on the basis of the inspection sample, I have given this component of my inspection a rating 3 (adequate).

During the intervention visit, opportunity was taken to inspect station's response to incidents on the site, including those notified to ONR, and I consider that the inspections conducted confirm that they have responded adequately to emergent plant conditions. On the basis of the sample inspections, I judge that they have complied with licence condition arrangements in relation to emergent work, which has arisen since the previous inspection visit and is not covered separately in this report; hence I consider their response to this aspect of my inspection is adequate.

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

Conclusion of Intervention

From the information gathered and evidence obtained during this intervention, no matters have been identified that are likely to have an adverse impact on nuclear safety on the station at this time. Therefore, I consider that no additional regulatory action arising from this visit is necessary currently, and the interventions for Wylfa power station should continue to be implemented as set out in the Integrated Intervention Strategy. I judge the corrective action taken by station in response to emergent matters to be appropriate in the prevailing circumstances. The outcome from the inspections has been captured within the station event and action tracking arrangements as necessary, in the actions recorded in this intervention report, and in the ONR issues database as appropriate.