Office for Nuclear Regulation

Hunterston B – Inspection ID: 51008

Executive summary

Date(s) of inspection:

  • February 2023

Aim of inspection

To examine the Hunterston B programme for management and processing of accumulated ILW sludges and resins

Subject(s) of inspection

  • LC 32 – Accumulation of radioactive waste – rating: Green

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

Under licence condition 32, specialist ONR inspectors carried out an inspection of the programme of work to specify and then build an operational waste processing facility (OWPF) for management of intermediate level wastes (ILW) at Hunterston B.

The inspection confirmed to EDF that management of ILW at Hunterston B is an area of joint regulatory interest with SEPA. The inspection examined the programme of work to design and build a new facility or to refurbish an existing building for the OWPF. The inspection identified some areas where ONR wished to engage further with EDF on the scope of the initial optioneering assessment for the OWPF and ONR noted the design appeared to be less mature than we would have expected for this stage in the decision making process.


In summary we noted the positive engagement during the HNA WILWREP plant visit and the opportunity this presented to communicate the regulatory expectations for the design of plant for management of wet ILW at HNB. We advised EDF that the principal area of regulatory interest was the management of ILW resins and the regulators wished to engage further on the design standards, optioneering and BPM studies being prepared for the OWPF.

Initial actions agreed actions were:

  1. To provide ONR and SEPA with the specification for the OWPF BPM assessment. This was subsequently provided, CM9 reference 2023/14971.
  2. Provide the operation experience on encapsulation of resins in 160 litre cans followed by further encapsulation in 3m3 boxes.
  3. EDF to propose an engagement programme for the regulators to provide advice on the design standards, optioneering and BPM studies being prepared for the OWPF.

We noted we would raise a regulatory issue [RI-11275] to track progress against the findings in this inspection report and to provide a record of the regulatory actions taken to influence the design of the OWPF.

In conclusion we acknowledged that the EDF programme to manage the accumulation of radioactive waste at HNB remained at the early development stage. Some areas were identified where further engagement with ONR and SEPA is required to confirm that regulatory expectations for control of ILW wastes will be achieved. Therefore we rated this inspection as LC32 Green, (no formal action) and a regulatory issue will be raised to track progress against our expectations.