Office for Nuclear Regulation

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Sellafield PMF(N) Ventilation Systems Inspection

Executive summary

Purpose of intervention

To assess the adequacy of the ventilation systems supporting the Finishing Line 3 (FL3) and Finishing Line 5 (FL5) facility safety cases.

Interventions Carried Out by ONR

A system based inspection incorporating:

A review of the safety case.

A tour of the facilities and inspection of the key ventilation equipment.

One to one reviews of the adequacy of the safety system with SL specialists; radiological protection, mechanical, electrical and training.

A close out meeting to discuss the high level points arising from the intervention.

Explanation of Judgement if Safety System Not Judged to be Adequate

The arrangements for ventilation on FL3 are based on the use of very old equipment that was designed and built to old standards.  Not surprisingly, the system falls well below modern standards. In addition, the system is operating in a non-standard manner with a C5 contaminated decommissioning area existing in the heart of the building (for the decommissioning of the original Pu production line). The standard of containment and ventilation of this area on the first floor is not suitable or sufficient to provide adequate standards of protection against contamination leaking from the C5 decommissioning area directly to normally manned C2 corridors.

The current operating state of the plant is unacceptable, however, I was encouraged that this had been recognised by the facility and they are currently making adequate progress working up a ventilation improvement project to address the many individual issues with the system.

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

The key findings, broken down by Licence Condition, from the intervention are as follows:

Conclusion of Intervention

The ventilation system is not considered adequate. The open and honest response of the facility to the inspection and the work that is being done to remedy the situation regarding the significant shortfalls in the containment and ventilation systems, have been taken into account in the response from ONR. Nine issues have been raised and will be managed by the ONR plan owner.

SL recognised the importance of the project to address the inadequacy of the current containment and ventilation systems and that the work was effectively governed and co-ordinated. ONR will provide regulatory oversight of the content and delivery of this work.

We consider that the appropriate course of action is to refrain from formal enforcement action at this stage, and to monitor and support the ventilation system improvement and decommissioning projects already underway. Future formal enforcement action, as always, remains an option should adequate progress fail to be made.