Executive summary
Date(s) of inspection
- December 2025
Aim of inspection
See - ONRW-932509302-22175
Subject(s) of inspection
- LC8 - Warning notices - Rating: GREEN
- LC9 - Instructions to persons on the site - Rating: GREEN
- LC11 - Emergency arrangements - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
This was a planned inspection in response to an event reported to ONR (INF-3263) related to criticality emergency response within general thoroughfares of separation area of Sellafield site. The aim of the inspection was to gain assurance that in the event of a criticality, personnel within the Prompt Evacuation Zone (PEZ) would respond appropriately. This assurance was to be gained through evidence of personnel demonstrating an understanding of the expected response in the event of a criticality alarm within the focus areas of B314 and general areas in separation area. The focus of the inspection was compliance with Licence Condition (LC) 8, 9 and 11.
Sellafield Ltd provided an overview of the:
- Criticality emergency arrangements
- Compliance with LC8 and 9 for criticality within the focus areas and;
- Management investigation carried out in response to INF-3263.
I walked down the criticality route within SEP area and asked 38 individuals in/near to the PEZ the following questions:
- Do you hold a supervisory role?
- Do you know what the criticality alarm sounds like and can you describe it to me?
- How would you respond to a criticality alarm in SEP area?
- Can you identify any signs associated with criticality in this area?
- Do you understand the criticality hazard and why the response is important?
The results were as follows:
- 11 were supervisors
- 28 knew what the alarm sounded like/could describe it
- 28 knew the appropriate response
- 28 could identify criticality related signage
- 24 could give some description of criticality and why the response is important
Overall I noted the clear progress that Sellafield Ltd have made since the original incident occurred. There were clear examples of good practice including the Management Investigation and Criticality Improvements Group set up in the aftermath. Whilst there were still some shortfalls associated with personnel understanding of criticality incident response I am content that there has been a marked improvement in this area as demonstrated by the plant walkdown, this provides confidence that in the event of a criticality personnel will respond appropriately. As such I deem an overall rating of Green to be appropriate.
Conclusion
Licence Condition 8
I was content that during the plant walkdown the criticality signage was clear and there is now clear ownership relating to signs within the general SEP area. As such I provided a rating of Green for LC8.
Licence Condition 9
There has been clear improvement in training aids used to notify personnel within SEP area of alarms in particular a new video as part of mandatory C2/R2 training focuses on criticality awareness. I recognise that some actions from the management investigation should ensure personnel understand the risks posed from a criticality incident, however this was not reflected in findings during the plant walkdown. Whilst this is a shortfall I recognise the improvements that have been made as a result of the steering group and note that Sellafield Ltd are aware that this is the start of the embedding process for learning relating to criticality. Therefore, I am content that for LC9 a rating of Green is appropriate
Licence Condition 11
Sellafield Ltd were able to clearly explain the rationale for the derivation of the Prompt Evacuation Zone, the expected response for a criticality incident within the focus areas and assurance that personnel are aware of the expected response. Given the response rate within the plant walkdown I judge for LC11 a rating of green is appropriate.
Overall I noted the clear progress that Sellafield Ltd have made since the original incident occurred. There were clear examples of good practice including the Management Investigation and Criticality Improvements Group set up in the aftermath. Whilst there were still some shortfalls associated with personnel understanding of criticality incident response I am content that there has been a marked improvement in this area as demonstrated by the plant walkdown. As such I deem an overall rating of Green to be appropriate.