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Sizewell B - Inspection ID: 52983

Executive summary

Date(s) of inspection: March 2024

Aim of inspection

In accordance with the Office for Nuclear Regulation’s (ONR’s) Operating Facilities Strategy, ONR undertakes a series of planned inspections targeted at fire safety. Fire hazards, if not controlled, can present risks to safety (nuclear and conventional) including common cause failure of safety systems. It is therefore important that the risks from fire are suitably controlled.

The aim of this inspection was to undertake a planned fire safety inspection at SZB to determine the adequacy of implementation of the Licensee’s claims associated with fire prevention and protection to ensure fire risks (conventional and nuclear) are reduced as low as reasonably practicable. In addition, this inspection will also include a review of the fire safety arrangements for building modifications given there are a number of new building developments at SZB.

Subject(s) of inspection

  • Fire (Life Safety) Compliance Inspection - Rating: Green
  • LC10 - Training - Rating: Green
  • LC23 - Operating rules - Rating: Green
  • LC24 - Operating instructions - Rating: Green
  • LC27 - Safety mechanisms, devices and circuits - Rating: Green
  • LC28 - Examination, inspection, maintenance and testing - Rating: Green
  • Overall Inspection Rating - Rating: Green

Key findings, inspector's opinions and reasons for judgement made

This was a planned inspection at the EDF-NGL Sizewell B (SZB) site. The inspection was undertaken as part of the intervention strategy for Operating Reactors Sub-Division.

This fire safety inspection at SZB considered both Nuclear and Life Fire Safety (LFS) and was undertaken by the Nominated Site Inspector, Fire Specialist, Internal Hazard and Fault Analysis Inspectors to determine whether fire risks are suitably controlled.

The inspection assessed the implementation of arrangements for managing life fire risks by reviewing compliance against the requirements of the Regulatory Reform (Fire Safety) Order 2005 (FSO) and compliance against the requirement of Licence Conditions LC10 Training, LC23 Operating Rules, LC24 Operating Instructions, LC27 Safety Mechanisms, Devices & Circuits & LC28 Examination, Inspection, Maintenance and Testing.

The inspection consisted of a review of the implementation of the licensee’s fire safety arrangements; review of fire safety case documentation, a sample of fire risk assessments and a plant walkdown. The inspection also included a review of building modifications given there are a number of new building developments at SZB.

The inspection focussed on areas of the Control Building, Reactor Building, Turbine Hall, Steam and Feed Cell, New Outage Store building, the Administration and Training Buildings and Temporary Accommodation Units.

Training

TI sampled the training records for several operators that fulfil roles associated with the fire system. This included, the Fire Systems Co-ordinator (FSC) and Fire System Engineers (SEs). I considered that EDF NGL is adequately implementing its training arrangements. All the staff sampled were new to post and are in the process of undertaking the relevant fire training currently identified in line with procedures and have support in place to carry out the fire related aspects of their role. I judge that EDF NGL is adequately implementing its arrangements with respect to Training and award a Green rating for LC10 & FSO.

Operating Rules & Operating Instructions

I sampled the Technical Specifications to determine how the principal limits and conditions from the fire safety case were identified in the specifications and enacted into station procedures and operator surveillances. I considered the principal limits and conditions were identified in the Technical Specifications appropriately and that the surveillance requirements I sampled were being undertaken in line with operating procedures.I sampled the several operating instructions for undertaking evaluations on the operability of fire barriers and procedures to be followed when a fire protection system is impaired. I considered the instructions were clear and unambiguous.

I judge that EDF NGL is adequately implementing its arrangements with respect to Operating Rules and Operating Instructions and award a Green rating for LC23, LC24 &FSO.

Safety Mechanisms, Devices & Circuits & Examination, Inspection, Maintenance and Testing (EIMT)

I sampled the EIMT records on several components of the Fire Protection System including fire dampers, fire doors, smoke vents, fire barriers and fire suppression. I considered the equipment was maintained in accordance with the safety case requirements. Also based on the plant walkdown and review of maintenance activities I considered that suitable and sufficient safety mechanisms, devices and circuits were connected and in good working order to demonstrate compliance against LC27. As such, I judge that EDF NGL is adequately implementing its arrangements and award a Green rating for LC27, LC2 8 & FSO.

Regulatory Reform (Fire Safety) Order 2005

I sampled the life fire safety management arrangements. This included reviewing a selection of Fire Risk Assessments and reviewing fire safety arrangements for building modifications. Based on my sample I found adequate evidence for compliance with the FSO. Advice and observations were raised in a couple of areas but these were not of sufficient significance to affect the overall rating. I judge that overall EDF NGL is adequately implementing its arrangements with respect to compliance with the Regulatory Reform ( Fire Safety) Order 2005 and award an Green rating for this part of the inspection.

Conclusion

Overall, based on my sample I found that EDF NGL’s existing arrangements made under LC10, LC23, LC24, LC27 and LC28 and the requirements of the Regulatory Reform (Fire Safety) Order 2005 are adequate for controlling risks related to fire hazards. From the evidence sampled during this SBI I judge that there were no matters that have the potential to impact significantly on nuclear or life safety.

During the inspection I identified some observations / advice for consideration. These were not significant matters and do not impact on the overall adequate provision of safety.

Inspection findings were shared with and accepted by EDF NGL as part of inspection feedback.

I consider that EDF NGL adequately demonstrated ownership and implementation of the fire protection systems safety case to ensure and maintain nuclear safety and life fire safety and on that basis award EDF NGL a green rating for both elements of the inspection.