Office for Nuclear Regulation

Hunterston B – Inspection ID: 52539

Executive summary

Date(s) of inspection:

  • August 2023

Aim of inspection

This is a planned inspection of EDF Energy Nuclear Generation Ltd.’s (NGL’s) Hunterston B Power Station, undertaken as part of the planned intervention strategy for the Operating Facilities Division (OFD) of the Office for Nuclear Regulation (ONR). The work was carried out in accordance with the planned inspection programme contained in the Hunterston B Integrated Intervention Strategy (IIS) for 2023/24.

The purpose of this intervention was to judge the adequacy of the implementation of the safety case for the Hunterston B Fuel Route.  In particular the safe handling of the fuel in the charge machine and Irradiated Fuel Dismantling Cell 1 (IFD1).

Subject(s) of inspection

  • 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
  • LC34 – Leakage and escape of radioactive material and radioactive waste – Rating: Not rated
  • Overall Inspection Rating – Rating: Green

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

The purpose of this intervention was to judge the adequacy of the implementation of the safety case for the Hunterston B fuel route. The two day on-site System Based Inspection (SBI) of the Hunterston B fuel route was led by the ONR nominated site inspector supported by an ONR specialist fault studies inspector and another site inspector.  The inspection comprised discussions with Hunterston B staff, a plant inspection and reviews of plant records and other documentation.

Prior to this intervention a review of the Off-Load Depressurised Defueling (ODD) safety case and associated faults/hazards was undertaken to identity the inspection sample.  This review identified the movement of irradiated fuel between the reactor and the flask storage bay via the Irradiated Fuel Dismantling cell 1 (IFD1) and pond (i.e. fuel route) as an area of higher risk.  This inspection therefore targeted the control measures in place to prevent a dropped fuel plug or fuel stringer.


From the areas sampled I judged that Hunterston B had met the legal requirements and therefore an inspection rating of Green (no formal action) is merited.  I also judged that Hunterston B had adequately implemented the requirement of the ODD safety case. A number of minor shortfalls were identified during the inspection relating to record keeping and plant condition.  I judged these did not undermine safe defueling operations but advised the station that these needed addressing. In light of the low safety significance I will follow these up as part of routine business.