Office for Nuclear Regulation

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Planned inspection of Dungeness A

Executive summary

Purpose of Intervention

This inspection of Magnox Ltd.'s Dungeness A nuclear licensed site was one of series of planned interventions as outlined in the Integrated Intervention Strategy (IIS) for 2017/18.

Interventions Carried Out by ONR

During this inspection, I carried out a project orientated systems based inspection on the inactive commissioning of the Advanced Active Drying System (AVDS) plant that will dry intermediate level waste so that it is in a passive condition during storage. The inspection was to verify compliance with the following Licence Conditions:

I also undertook a fact finding inspection into an incident where the fire brigade attended site to assist with a minor fire and several other minor incidents. I attended the Dungeness SSG meeting and answered questions relating to the decommissioning programme and care and maintenance arrangements at Bradwell.

Explanation of Judgement if Safety System Not Judged to be Adequate

The inactive commissioning of the AVDS plant had proved the system adequate to deliver the safety functions in the safety case and there is no reason why the system should not progress to active commissioning.

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

I am satisfied that the licensee's arrangements for the inactive commissioning of the AVDS plant meet relevant good practice. A minor incident occurred during inactive commissioning, however I do not judge that this is a serious matter. I am satisfied that these arrangements were adequately implemented on site: I have rated compliance with Licence Conditions 10, 23, 24, 27, 28 and 34 as adequate. The plant has been designed and built by a core team of engineers drawing on previous experience with this type of plant at other sites. The quality plan and commissioning procedures have been produced to a high quality.

A suitable and sufficient response was mounted to deal with the incident involving a minor fire causing smoke to enter the Active Effluent Water Treatment plant facility causing a fire alarm and muster. The incident has been investigated and appropriate measures taken to prevent any recurrence.

Further incidents involving an escape of water during inactive commissioning of the AVDS plant and mis-direction of contaminated waste into non active skips were also followed up. I was satisfied that they did not represent serious risks to nuclear safety.

Conclusions of Intervention

From the evidence gathered during this intervention I consider that: