Office for Nuclear Regulation

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System Based Inspection of the fire protection systems within the Magnox Reprocessing Facility Sellafield

Executive summary

Purpose of Intervention

The Office for Nuclear Regulation (ONR) undertakes all regulatory interaction with the Sellafield site licensee (Sellafield Limited (SL)) against a strategy defined by the ONR Sellafield SCIE sub-Division. 

In accordance with that Strategy, a system based inspection (SBI) of the fire protection systems (fire detection and fire suppression) within the Magnox Operating Unit was planned for July 2017.  The purpose of this planned inspection was for ONR to confirm the adequacy of implementation of the licensee’s safety case claims in respect of these systems.

As part of each SBI, the ONR examines evidence of the adequate implementation of six pre-defined licence conditions.  These licence conditions (listed below) have been selected because of their importance to nuclear safety, and are defined within the ONR’s formal process for delivery of an SBI.

Interventions Carried Out by ONR

LC 10 requires SL to make and implement adequate arrangements for suitable training of those who have responsibility for any operations that may affect safety.

LC 23 requires SL to produce adequate safety cases to demonstrate the safety of its operations, and to identify the operating conditions and limits necessary in the interests of safety.

LC 24 requires SL to make and implement adequate arrangements for the provision of suitable written instructions for undertaking any operation that may affect safety.

LC 27 requires SL to ensure that, before a system is operated, inspected, maintained or tested, there are suitable and sufficient safety mechanisms, devices and circuits properly connected and in good working order.

LC 28 requires SL to make and implement adequate arrangements for the regular and systematic examination, inspection, maintenance and testing of all plant which may affect safety.

LC 34 requires SL to ensure that its radioactive material and radioactive waste is at all times adequately controlled and contained, and that no leak or escape of that material or waste can take place without being detected.  For this inspection, I considered that inspection against implementation of this Licence Condition would not be relevant, based on the system functions, and the fact that no radioactive material is controlled or confined by the system.

I led a two-day, on-site, SBI of the fire protection systems within the Magnox Reprocessing facility (MRF), which is part of the Magnox OU.  The inspection comprised discussions with SL staff, plant walk downs and reviews of plant records and other documentation.

Explanation of Judgement if Safety System Not Judged to be Adequate

The fire protection system was judged to be adequate.

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

From the evidence examined during this inspection, I consider that SL has adequately implemented those claims within the facility safety case that I sampled, relating to the fire protection system.

As part of the scope of this SBI, I considered if the related facility safety case might require an ONR assessment of adequacy in a timeframe shorter than currently planned.  Although the safety case documentation is structured in a manner that does not always allow efficient extraction of information by the operator, based on the evidence sampled I have no reason to recommend an early assessment of the safety case for this system.

During this inspection, I reviewed evidence of adequate training against the system function, including the effective operation of suppression systems.  Additionally, I sampled a range of maintenance activities for components across the system and consider that, in all cases, they provided adequate evidence of asset maintenance and inspection.

However, I considered that, while the licensee had some evidence of system performance, they had not gained full confidence in the end-to-end functional performance of the detection system.  Additionally, during plant inspections, I identified some evidence of poor component condition, and minor shortfalls in asset care/management.  Whilst each shortfall is not sufficiently significant to merit formal regulatory action, aggregation does indicate that the system asset condition may not be at the standard expected.  Consequently, I have raised an ONR Regulatory Issue to track the progress to completion of the licensee’s actions to address this shortfall. 

Based on the sampled evidence, I consider that a rating of Green (no formal action) is merited for Licence Conditions 10, 23, 24, and 28.  For Licence Condition 27, I consider that a rating of Amber (seek improvement) is merited, as the currently installed condition and related function of some of the system components was not to the standard I, or the licensee, would expect.

Conclusion of Intervention

From the evidence sampled during this inspection, I judge that the licensee has implemented adequately the sampled claims within its safety case.  Additionally, on the basis of the evidence requested and reviewed, I consider that the licensee’s formal arrangements for compliance with Licence Conditions 10, 23, 24 and 28 are also being implemented adequately, but that shortfalls in compliance have been identified against Licence Condition 27.