Office for Nuclear Regulation

Sizewell B – Inspection ID: 51251

Executive summary

Date(s) of inspection:

  • March 2023

Aim of inspection

The aim of this intervention was to undertake a planned licence condition (LC) compliance inspection of LC 9 (instructions to persons on the site) at Sizewell B.

This inspection was undertaken as part of a series of planned inspections described in the Integrated Intervention Strategy (IIS) for SIzewell B.

Subject(s) of inspection

  • LC 09 – Instructions to persons on the site – Rating: Green

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

During refuelling outages, large numbers of contractors will be brought onto site to undertake the necessary outage activities. I sampled the training courses required to be undertaken for unescorted access to:

  • The site in general;
  • The radiation controlled area (RCA), including the containment building;
  • The containment building specifically.

I sampled three courses in all:

  • The dynamic learning activity (DLA) course that is a requirement for the issue of an unescorted access pass during the outage;
  • The radiation controlled area (RCA) dressing & undressing course required for unescorted access to the RCA (which includes the containment building);
  • The foreign material exclusion (FME) course that is required for access (escorted or unescorted) into the containment building.

I was satisfied with the content of all three courses. I consider the use of the flow loop simulator (a physical mock-up of a plant area) to demonstrate the various potential hazards and controls to be an area of good practice.


On the basis of the courses sampled, I am satisfied that persons coming to site for the refuelling outage will only be allowed unescorted access to the site or the containment building if they have been provided with appropriate information regarding:

  • The risks and hazards associated with the site in general and the RCA and containment building in particular;
  • The precautions to be observed in connection with those risks and hazards;
  • The action to be taken in the event of an accident or emergency on the site.

I therefore consider an inspection rating of green (no formal action) to be appropriate for compliance with LC 9. I do not consider that any changes are needed for the ongoing IIS for the site.