Office for Nuclear Regulation

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Wylfa - Planned intervention

Executive summary

Purpose of intervention

Planned intervention at Magnox Ltd’s Wylfa licensed site, undertaken as part of a series of planned interventions outlined in the ONR Integrated Intervention Strategy (IIS) Plan Wylfa Power Station 2014/2015.

Interventions Carried Out by ONR

Planned compliance inspections of Licence Condition 23 ‘Operating Rules’, 24 ‘Operating Instructions’, 11 ‘Emergency Arrangements’ and Radiation Emergency Preparedness and Public Information Regulations (REPPIR)  were undertaken. In addition a number of liaison meetings were held to progress general matters of interest.

Explanation of Judgement if Safety System Not Judged to be Adequate

No safety system based inspections were undertaken during this intervention.

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

A specialist chemistry inspection was undertaken, particularly focused on Licence Condition 23 (LC23) and 24 (LC24) compliance, in addition to a number of other chemistry related matters. The purpose of this inspection was to determine if the licensee exercises adequate control of chemistry to minimise materials degradation, radiation exposure and radwaste production and specifically how the arrangements to do so meet the requirements of LC23 and 24:

In terms of LC23, I consider that the licensee has adequately defined the limit and conditions necessary for chemistry control. These are consistently and clearly implemented into station documentation and have been shown to be maintained and up to date. An area for improvement relating to the link to the safety case and the underlying safety basis for the specific limits was identified.  Despite this, it is recognised that station personnel clearly understand the implications of inadequate chemistry control. An IIS rating of 3, adequate, is assigned. 

For LC24, the licensee has a comprehensive set of chemistry related operating instructions which were clear and unambiguous and link to the chemistry related limits and conditions that must be maintained. I note some potential minor areas for improvement, but overall I consider the instructions fit for purpose and I therefore assign a rating of 3, adequate, for LC24.

My overall impression on completion of this chemistry based inspection at Wylfa is that the control and delivery of chemistry on the site is adequate. Of particular note is the level of knowledge and experience displayed by the chemistry team during my inspection. I have noted some areas for potential improvement for the licensee to consider, but I judge that the fundamental safety requirements are being met.

The inspection of the site arrangements for compliance with Licence Condition 11 and REPPIR examined a sample of Magnox Ltd’s procedures addressing the requirements for these two elements of legislation. The inspection was supported by the observation of the annual Level 1 emergency exercise. The inspection concluded that an adequate demonstration of the site emergency arrangements was provided. An area for improvement relating to the search and subsequent rescue of casualties was identified and it was concluded that whilst the fundamental requirements of the licence condition were met, Magnox Ltd need to either improve arrangements in this area or the implementation of those arrangements. ONR proposes to undertake further inspection and engagement with Wylfa emergency preparedness team to identify potential improvement opportunities.

Liaison meetings covered the following topic:

For each of the topics covered suitable responses by either Magnox Ltd or ONR were identified to progress matters towards adequate conclusions.

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

There are no findings from this inspection that could significantly undermine nuclear safety and no change to the planned interventions and inspections of Wylfa power station.