Office for Nuclear Regulation

Sizewell B – Inspection ID: 52764

Date(s) of inspection

  • July 2023

Executive summary

Aim of inspection

The aim of this intervention was to undertake a planned licence condition (LC) compliance inspection of LC10 (training) at Sizewell B. This inspection was undertaken as part of a series of planned inspections described in the Integrated Intervention Strategy (IIS) for the site.

This intervention considered the adequacy of training in a number of areas, informed by ONR specialist inspectors from a number of disciplines:

  • Reactivity management.
  • RiskWatcher, the site’s Probabilistic Safety Assessment (PSA) software.
  • Ageing and obsolescence management and as-found condition code recording.
  • Visual inspection of components.

Subject(s) of inspection

  • LC10 – Training – Rating: Green

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

By examining documentation and speaking to a variety of operators, maintenance personnel and nuclear safety group staff we determined that:

  • Training needs associated with reactivity management (including the need for ongoing or refresher training) have been documented, and that post holders have received the relevant training and have any necessary follow-up training scheduled.
  • Training needs associated with the use of RiskWatcher were well identified, and the relevant training delivered, for shift managers and control room supervisors, and for nuclear safety group users. However, we did observe some shortfalls in the definition and recording of training for reactor operators and work week managers. In practice, those individuals had received appropriate training but the process for delivering this training is not formalised. We raised a regulatory issue for the licensee to address this shortfall.
  • Training for aging and obsolescence management and as-found condition recording has been developed and is being delivered to relevant engineering and maintenance staff across the site.
    The specific requirements of the American Society of Mechanical Engineers (ASME) for the training of individuals undertaking visual inspections had been captured in licensee’s procedures. Staff undertaking such inspections during the most recent refuelling outage could demonstrate that they had received the appropriate training.


Overall I was satisfied that the licensee had adequate arrangements for training in a variety of areas, and have awarded a green rating for compliance with LC10. There were some minor shortfalls associated with the rigour with which training was delivered to a small subset of RiskWatcher users. I do not consider this to be a safety risk in practice, and have raised RI-11639 for the licensee to address the shortfalls. I found no issues which might affect nuclear safety or which will require amendments to the IIS plan.