Office for Nuclear Regulation

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Sellafield - Essential Operations Inspection of the PFCS Metal Fire Fighting Capability

Executive summary

Purpose of intervention

The current ONR regulatory strategy for Sellafield Ltd (SL) is focussed on stimulating, facilitating and expediting hazard and risk reduction. ONR has a number of planned interventions in place to ensure hazard and risk reduction activities are delivered safely.

This intervention focuses on the actions taken by SL in response to a Regulatory Issue (RI) regarding ONR concerns on the absence of protocols and specific media for fighting metal fires. The purpose of the intervention is therefore to determine the extent to which SL has progressed actions against this RI.

The intervention reported in this record is one of a series of 'essential operations inspections' designed to identify any potential shortfalls in the reliability and resilience of the functions underpinning a facility which is carrying out risk and hazard reduction activities.

Interventions Carried Out by ONR

SL has introduced new metal firefighting equipment and arrangements in response to recommendations from SL's Long Term Periodic Review relating to the PFCS Facilities' Severe Accident Management Strategy and concerns surrounding beyond design basis fault scenarios in light of post Fukushima resilience works.

An ONR inspection was previously conducted on the 09 - 10 March 2016 and determined that SL had installed and been able to demonstrate a metal firefighting capability for the Pile Fuel Cladding Silo (PFCS) facility. However, whilst regulator confidence was gained that the capability for fire detection and response was in place, weaknesses in arrangements and deployment was observed. As such, this inspection has therefore focussed specifically on SL's capability to demonstrate appropriate and timely decision making in response to indicators of a metal fire within the PFCS and subsequently deploy the metal firefighting capability in a timely manner.

The inspection was undertaken at the Sellafield site on the 5th May 2016. I was supported by the SL PFCS Internal Regulator.

Explanation of Judgement if Safety System Not judged to be Adequate

This was not a system based inspection.

Key Findings, Inspector's Opinions and reasons for Judgement made.

Although PFCS metal fires are considered to be unlikely, PFCS has installed new equipment to be able to fight an in-silo metal fire thereby mitigating risks associated with planned retrieval activities. SL has subsequently been able to demonstrate the deployment of this capability in an on-plant exercise.

The inspection scope had identified two objectives to align with the RI actions. Against the objectives I determined;

SL demonstrated effective and timely decision making in response to indicators of a metal fire within the PFCS. Once elevated plant parameters were detected, enhanced surveillance was quickly established and correctly focused on the at risk and adjacent silos whilst still continuing to maintain a regime for the remaining silos. At a predetermined trigger point, the emergency response was activated in a timely manner.

The SL Maintenance team responded and deployed firefighting equipment, supported by the Sellafield Fire and Rescue Team, without undue delay and in a timeframe that I would consider a realistic benchmark of performance

Conclusion of Intervention.

SL has installed and demonstrated a metal firefighting capability utilising fit for purpose commercial off the shelf equipment for PFCS. SL has made timely progress in selecting, procuring and installing the firefighting equipment.

The demonstration exercise witnessed on the 5th May 2016 has confirmed that, through clear and effective decision making, the firefighting equipment can be deployed in a timely basis. As such I have recommend that the RI actions relating to ONR attendance at a further metal firefighting training exercise be closed.

The remaining extant actions against the RI, will be followed up by the ONR project inspector in conjunction with the Sellafield internal regulator as part of normal regulatory business associated with addressing the RI.

I have raised no new Regulatory Issues as a result of this inspection.