Office for Nuclear Regulation

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Planned system-based inspection

Executive summary

Purpose of intervention

Planned intervention at Magnox Ltd’s Wylfa licensed site. This report covers the nuclear safety related inspection of Wylfa power station undertaken as part of a series of system based inspections (SBIs) deemed necessary to cover safety related systems as outlined in the Wylfa safety case.

Interventions Carried Out by ONR

This inspection bounded planned compliance inspections against the following Licence Conditions (LCs):

Licence Conditions 10, 23, 24, 27 & 28 were covered as the safety system inspection of the Wylfa power station arrangements for the fire protection systems.

In addition to the inspections identified above a number of liaison meetings were attended to monitor progress with current activities and maintain awareness of any matters of regulatory interest. These included the following topics:

Meeting with Safety Representatives

Review of recent issues and actions from regulatory inspections

Explanation of Judgement if Safety System Not Judged to be Adequate

On the basis of the inspection, I judge that overall, the fire protection systems, meet the requirements of the safety case and are, on the basis of this inspection, considered adequate.

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

A safety system inspection of the fire protection systems was undertaken as part of the programme of SBIs included on the Wylfa site intervention plan for 2014/15. The purpose of the inspection was to assess the adequacy of the station arrangements currently in place to ensure that the system safety function is delivered. In deciding if suitable and sufficient measures have indeed been adopted for the safety system, the inspection considered compliance with a number licence conditions. The standard consideration of licence conditions are bounded by LCs 10, 23, 24, 27 & 28.

A consolidated fire hazard safety case, Operating Rule associated with fire protection systems and suitable procedures for compliance exist and are broadly considered to be adequate. However, whilst the main operating instruction supporting the operating rule appears to be adequately implemented, some weaknesses in the procedures, and subsequent implementation for control of fire sterile zones have been identified. Consequently, an IIS rating of 3 is assigned to LC23 and IIS rating of 4 to LC24.

The overall condition of plant inspected was acceptable, and the site’s Plant Health Committee report showed an awareness of longer term issues and active management by Magnox Ltd. The fire protection systems and maintenance is considered to be adequate to meet the requirements of the safety case and an IIS rating of 3 is assigned to LCs 27 and 28.

The inspection confirmed that the safety case implementation had been supported by a specific awareness training package. The training provided to operators in relation to the fire hazards safety case is judged to be adequate and an IIS rating of 3  is assigned

During the SBI on Fire Protection Systems the Waste Transit Store was inspected. Whilst no concerns were evident regarding the installed fire detection system the apparent, control, management and storage of the waste did not meet regulatory expectations for adequate compliance with a number of related licence conditions and relevant statutory legislation by varying degrees. Previous inspections in this area by ONR almost two years ago resulted in an improvement programme that included this area. Whilst ONR recognise there has been an improvement in the amount of waste accumulated in this area the current storage arrangements remain significantly below the standard expected. Based on the slow progress addressing the current storage and working arrangements in the transit store following written advice from ONR in 2013 a reactive IIS rating of 5 is assigned to licence condition 4 in regard to the storage of nuclear matter. Site management have been advised that ONR will provide an appropriate regulatory response following consideration with the Enforcement Management Model.

The various liaison meetings undertaken provided useful updates on matters of regulatory interest and confirmed adequate progress being made by Magnox Ltd in delivering against the topics discussed.

Conclusion of Intervention

From the information obtained and evidence gathered during this intervention, I do not believe there are any matters identified that have a significant negative effect on the system integrity and there were no issues identified that were considered to adversely affect nuclear safety.

During the SBI on Fire Protection Systems the Waste Transit Store was inspected. The apparent, control, management and storage of the waste did not meet regulatory expectations for adequate compliance with a number of related licence conditions and relevant statutory legislation by varying degrees. Wylfa site management have been advised that ONR will provide an appropriate regulatory response following consideration with the Enforcement Management Model.