Office for Nuclear Regulation

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Site Inspection and Project Meeting (Level 4) Related to DNB Fire Improvement

Executive summary

Purpose of intervention

This report describes a planned inspection of the projects aimed at improving the robustness of the fire safety case at Dungeness B (DNB) power station.

The inspection is part of an ONR Intervention Project, established to monitor fire improvements at DNB in particular following a fire in the boiler house in 2009. The company addressed some issues immediately after the fire, and have continued to look for further improvements since. Some of the projects are extensive in scope and have necessarily taken several years to come to maturity. During 2014, one of the DNB reactors (reactor 21 - R21) is due to be shutdown for a statutory outage, and several significant fire improvement projects have been programmed for this outage. This inspection was to understand the nature of the challenges and the progress made in preparation for successful implementation of the fire improvements.

Interventions carried out by ONR

Our inspection had several elements - a plant inspection, a short meeting on the station's "fire safety excellence" plan, and a project meeting (level4) on the DNB fire improvements projects.

ONR was represented by the programme specialist inspectors for internal hazards (which includes fire), supported for part of the day with the nominated site inspector.

Explanation of judgement if safety system not judged to be adequate.

Not appropriate.

Key findings, Inspector's opinions and reasons for judgements made

The plant tour was viewed as very worthwhile, with good level of support from EDF NGL, and good interactions. Seeing the plant is invaluable in understanding the challenges to the plant, the value of the fire improvement projects, and the constraints that these projects operate against.

Similarly the short meeting with the Station Quality Management Group Head on the fire safety excellence plan allowed the current projects to be seen in the context of a wider company agenda to improve the site safety culture and awareness of fire issues, and the management of fire hazards, and of fire detection and suppression systems. Following a company-wide initiative to improve the site focus on fire issues, the station was able to show greatly improved performance metrics, which reflects a significant improvement in the management of fire safety issues.

The project meeting allowed EDF NGL to show good progress in preparing for the successful implementation of two fire improvement projects on R21 during the 2014 statutory outage. Progress has also been made on a number of other issues, including projects to review and revise the station nuclear safety case for fires affecting plant.

Less satisfactory news at the project meeting was that one of the fire improvement projects which had been targeted for the 2014 statutory outage had proved much more difficult than originally thought, and the company has had to accept it cannot be implemented this year as originally planned. We supported the company decision to defer this work for this year's outage; the judgement informed by the understanding of the plant and the project gained from the plant inspection. We requested that the station should clarify their forward intention for this project, and the expectation is that some of this clarity will be achieved by a revised interim fire safety case due in Spring 2014.

Conclusion of intervention

This was a worthwhile planned inspection of DNB, a useful meeting with station management, and a clear and honest project progress meeting.

Recommendations

No actions were placed on the licensee as a result of this site inspection.