Office for Nuclear Regulation

Hunterston B – Inspection ID: 22-049

  • Site: Hunterston B
  • IR number: 22-049
  • Date: July 2022
  • LC numbers: 35

Executive summary

Purpose of Intervention

This was a planned inspection of EDF Energy (EDFE) Nuclear Generation Ltd.’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 2022/23.

Interventions Carried Out by ONR

As part of this intervention the End of Generation (EoG) Project Inspector and nominated Site Inspector for Hunterston B carried out a compliance inspection against:

  • Licence condition (LC) 35 – Decommissioning.

The intervention was performed in line with ONR’s guidance requirements (as described in our technical inspection guides) in the areas inspected.

Explanation of Judgement if Safety System Not Judged to be Adequate

No system based inspection was undertaken hence, this is not applicable for this intervention.

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

The inspection confirmed:

  • The station plans for early deconstruction preparations which are currently funded are mature and those that are not funded require further maturation.  A logic linked plan of all deconstruction preparation activities planned to be completed prior to fuel free verification (FFV) is required.
  • A robust process to undertake plant walkdowns to inform risk-based deplanting proposals has been developed and implemented.  Enhancing written guidance to inform the judgements of those undertaking walkdowns would facilitate transfer of learning from Hunterston B to other stations preparing for deconstruction.
  • The extant authorised LC 35 arrangements do not reflect the extant ways of working under the Co-operation Agreement.  The governance and oversight process applied to the evolving station deconstruction plan is not in accordance with the authorised LC 35 arrangements.  The scope of the proposed changes to the extant authorised LC35 arrangements is not in accordance with regulatory expectations.  Improvements are required to close the compliance gap.
  • The Strategic Outcome Specification (SOS) sets out the strategic outcomes to be delivered by the decommissioning of EDFE’s advanced gas-cooled reactor stations.  There is not a clear line of sight between the SOS and the station work plans for early deconstruction preparations, and it is not clear how the SOS facilitates prioritisation of the work plans.  A further LC 35 inspection will be undertaken in a year to enable the logic linked plan for all deconstruction preparation activities planned to be completed prior to FFV will be examined as will how prioritisation is undertaken.

Conclusion of Intervention

The inspection against LC35 did not identify any matters that could significantly undermine nuclear safety but did identify EDFE is not working in accordance with its extant authorised LC35 arrangements.  Therefore, a rating of Amber, seek improvement, was assigned to the inspection.  A level 3 regulatory issue will be raised to capture the improvement programme to close the compliance gap and an enforcement letter will be issued.