- Site: Sellafield
- IR number: 21-145
- Date: December 2021
- LC numbers: 10, 23, 24, 27, 28
Executive summary
Purpose of Intervention
The Office for Nuclear Regulation (ONR) undertakes all regulatory interaction with the Sellafield site licensee, Sellafield Limited, against a strategy defined by the ONR Sellafield, Decommissioning, Fuel and Waste Division. In accordance with that strategy, two System Based Inspections (SBI) were planned covering essential services and fire safety. In the interests of efficient and effective regulation and due to the fact that both of the systems were of relatively low complexity it was decided to conduct one intervention to inspect both systems, this also reduced the burden on the Licensee who would only be required to support one inspection.
However, in reviewing evidence before and during the inspection it became evident that the nuclear safety case requirements in respect of fire safety in FGMSP were limited due to the nature in which the nuclear matter is currently stored, i.e. in the FGMSP pond or in an oxidised state. Therefore, the SBI was not carried out, instead an inspection targeting the fire system in respect of detection and alarm on the First Generation Magnox Storage Pond (FGMSP) was conducted against the Regulatory Reform (Fire Safety) Order 2005.
Both systems were inspected using the same framework, where applicable, which is used during SBI’s. The purpose of the essential services SBI was for ONR to examine whether the licensee’s safety case claims in respect of the FGMSP essential services (steam, electrical, air, water supplies) systems had been adequately implemented.
The inspection comprised discussions with Sellafield Limited staff, a targeted plant walkdown and a review of plant records and other documentation.
Interventions Carried Out by ONR
ONR’s SBI process examines evidence to determine compliance against six licence conditions (LC). These LC’s, listed below, have been selected in view of their relevance to ensuring nuclear safety and provide a structured approach to determining whether the safety case has been implemented adequately through the system being inspected.
LC 10 requires Sellafield Limited to make and implement adequate arrangements for suitable training for all those on site who have responsibility for any operations which may affect safety.
LC23 requires Sellafield Limited to produce an adequate safety case to demonstrate the safety of its operations, and to identify the conditions and limits necessary in the interests of safety.
LC24 requires Sellafield Limited to ensure that all operations which may affect safety are carried out in accordance with written instructions.
LC27 requires Sellafield Limited to ensure that a plant is not operated, inspected, maintained or tested unless suitable safety mechanisms, devices and circuits are properly connected and in good working order.
LC28 requires Sellafield Limited to make and implement adequate arrangements for the regular and systematic examination, inspection, maintenance and testing of all plant which may affect safety.
LC34 requires Sellafield Limited to ensure, so far as is reasonably practicable, that radioactive material and radioactive waste on the site is at all times adequately controlled or contained so that it cannot leak or otherwise escape from such control or containment.
The inspection was performed in accordance with ONR guidance (detailed in ONR inspection guidance) available at: http://www.onr.org.uk/operational/tech_insp_guides/index.htm
In the case of the fire system, the inspection sampled evidence for the adequacy of training, operating instructions, asset condition and examination, inspection maintenance and testing in respect of the Regulatory Reform (Fire Safety) Order 2005. As the operating rules and the leakage and escape of radioactive material normally inspected under LCs 23 and 34 were not applicable to this system, evidence was not sampled.
Explanation of Judgement if Safety System Not Judged to be Adequate
The Licensee has demonstrated that the Structures, Systems and Components (SSCs) which have been inspected as part of the FGMSP essential services systems meet the requirements of the safety case.
In FGMSP the fire safety system is not part of the safety case but is designated as Safety Related Equipment (SRE) under management discretion and therefore the judgement as to whether it meets the requirements of the safety case was not applicable.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
Essential Services
Based on the evidence sampled during this inspection, I judge that FGMSP has adequately implemented those safety case claims that relate to the essential services system. I consider in respect of LCs 10, 23, 24, 27 and 28 noting the ONR guidance on inspection ratings, that an inspection rating of Green (no formal action required) is merited here.
The essential services systems inspected include steam, water, air and electricity and during the course of the inspection there was insufficient evidence to support a rating for LC34, however there were no areas of concern identified. Therefore, a rating was not provided.
I identified a minor shortfall in relation to essential services. I raised this as an ONR Regulatory Issue at Level 4 (lowest level).
Fire Safety
Based on the evidence sampled during this inspection, I identified significant shortfalls in the fire alarm and detection system. I therefore consider compliance against the Regulatory Reform (Fire Safety) Order 2005 is not adequate and therefore given an Amber inspection rating. These findings included deficiencies in the extent of system coverage within the facility, repeated faults, matters relating to obsolescence and adequacy of regular and systematic examination, inspection, maintenance and testing of the fire system. These findings have been identified in a Regulatory Issue at Level 3 against compliance with the Regulatory Reform (Fire Safety) Order 2005.
Conclusion of Intervention
I consider that the licensee has a good knowledge of the physical condition of the essential services, systems and components reviewed during this inspection. Overall, on balance, I consider the safety case supporting the essential services systems to be adequately implemented.
I identified a finding in relation to essential services which I have raised as an ONR Regulatory Issue at Level 4 (lowest level) to track progress on this matter.
I identified significant shortfalls in the fire alarm and detection system against the Regulatory Reform (Fire Safety) Order 2005 for which I have raised an ONR Regulatory Issue at Level 3.