Executive summary
Date(s) of inspection:
March 2026
Aim of inspection
The aim of the inspection was to sample Sellafield Limited's (SLs) arrangements for the Cooling Water Systems at the Highly Active Liquor Evaporation and Storage (HALES) facility, and how they mitigate the risk from Legionella.
Subject(s) of inspection
- COSHH (Legionella) - Rating: GREEN
- LC 23 - Operating rules - Rating: GREEN
- LC 24 - Operating instructions - Rating: GREEN
- LC 27 - Safety mechanisms, devices and circuits - Rating: GREEN
- LC 28 - Examination, inspection, maintenance and testing - Rating: AMBER
- Overall Inspection Rating - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
I conducted an inspection of Sellafield Limited's arrangements for the Cooling Water Systems at the Highly Active Liquor Evaporation and Storage (HALES) facility, and how they mitigate the risk from Legionella. The inspection was devised to sample the dutyholder's arrangements and implementation of the following Licence Conditions (LCs), with respect to the HALES cooling water system:
- LC23 (Operating Rules)
- LC24 (Operating Instructions)
- LC27 (Safety Mechanisms, Devices and Circuits)
- LC28 (Examination, Inspection, Maintenance and Testing)
The inspection also targeted the arrangements for the control of Legionella within the cooling water circuits, under the Control of Substances Hazardous to Health (COSHH) Legionella Regulations.
I was content with the dutyholder's implementation of their arrangements for LCs 23, 24 and 27. I was also content with how the dutyholder controls the risk of Legionella within the cooling water circuits. I sampled sufficient evidence to judge that it was appropriate to close the long standing Regulatory Issue (RI-5871), which was related to legionella control.
For LC28, I sampled the records associated with Safety Mechanisms (SMs) which had defects recorded against them, some of which were in place for several years. The dutyholder was unable to provide sufficient evidence to support continued operation, where this information was held, how it was revised considering other plant performance and other failures over time that may impact on the defective SMs to achieve their function, and if there was a reliance on any other measures. The approach did not meet my expectations for managing defects of SMs, and also highlights potential cultural issues of the toleration of degraded conditions.
Conclusion
Based upon my sample, I am content that an overall inspection rating of GREEN (no formal action) is appropriate. However, due to the lack of control of defects associated with Safety Mechanisms, I consider that a rating of AMBER (seek improvement) is appropriate against Licence Condition 28 and a Level 3 Regulatory Issue will be raised to address these shortfalls.
I have taken these shortfalls through ONR's Enforcement Management Model to decide if any further follow up action is required beyond the Level 3 Regulatory Issue and concluded that the proportionate enforcement action was to provide Regulatory Advice. I provided Regulatory Advice in relation to these shortfalls following the inspection which was accepted by the dutyholder.