Executive summary
Date(s) of inspection:
- March 2025
Aim of inspection
The aim of this intervention is to consider how Nuclear Restoration Services (NRS) Dounreay has implemented measures to comply with the Control of Major Accident Hazards (COMAH) Regulations 2015 as a lower tier COMAH operator.
The aims of the inspection are:
- to verify the major accident scenarios and determine whether control measures are adequate
- to verify whether emergency arrangements are commensurate with the level of risk
- to familiarise ourselves with the site and chemical storage arrangements.
Subject(s) of inspection
- COMAH - Control of Major Accident Hazards Regulations 2015 - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
This inspection undertaken by an inspector from the Office for Nuclear Regulation (ONR) Nuclear Internal Hazards and Site Safety (NIHSS) specialism and focussed on the Control of Major Accident Hazards Regulation 2015 (COMAH) and how Nuclear Restoration Services – Dounreay (NRS-D), as a lower tier COMAH operator, was ensuring compliance with the regulations.
The inspection involved three days on site, and consisting of office based discussions and a site walk down covering the main areas on site holding inventories of COMAH relevant substances, for example Fuel Cycle Area (FCA) buildings, the boiler house & associated fuel tanks, the Prototype Fast Reactor (PFR) Generator-Transformer House (GTH) and sodium tank farm. The inspection consisted of examination of the licensee’s safety management arrangements for implementing the measures described in their major accident prevention policy. The inspection was undertaken in parallel with a life fire safety inspection (IR-53691) with some joint engagement on areas of common interest for example fuel storage arrangements.
NRS-D were able to demonstrate that work was in progress to ensure that their existing safety management was being updated to reflect the COMAH major hazards identified on site. The inspection did identity that further work was required to ensure that COMAH relevant safety systems had the appropriate examination, inspection, maintenance and testing (EMIT) arrangements in place. This matter will be followed up via the existing level four regulatory issue (RI-12139 – COMAH- MAPP Development and Implementation).
Conclusion
I was able to verify that NRS-D had identified relevant COMAH major accident scenarios. I was only partially able to determine whether the control measures were adequate, and I propose to track this through existing pre-arranged engagement.
I was able to verify that the emergency arrangements were commensurate with the level of risk, although I have given credit for plans for training and exercising that were shared during the inspection. I propose to track progress with this work through existing pre-arranged engagement.
Overall the inspection showed that relevant good practice was generally met, NRS-D is still in the process of fully implementing the legal requirements for a lower tier COMAH operator. I judge that a GREEN (adequate) inspection rating is appropriate
ONR will continue to track issues through RI-12139. The outstanding action will be extended until end of September 2025. The routine regulatory engagement will continue but the focus will change from NRS-D providing an update on progress to them demonstrating their implementation of the items identified in the COMAH Implementation Actions spreadsheet.