Executive summary
- Date(s) of inspection: December 2024
Aim of inspection
The purpose of this intervention is to confirm adequate implementation of Dounreay’s current arrangements for storage of alkali metals and measures implemented to address compliance gaps identified in Improvement Notice ONR-23-3.
Subject(s) of inspection
- COSHH - Rating: Green
- LC4 - Restrictions on nuclear matter on the site - Rating: Green
Key findings, inspector's opinions and reasons for judgement made
In February 2024, ONR issued an Improvement Notice (IN-23-3) concerning the storage arrangements for bulk alkali metals at Prototype Fast Reactor (PFR). NRS Dounreay has established an improvement project to address the shortfalls identified. This inspection included, but was not limited to, the areas of work covered by the improvement project.
NRS Dounreay presented an overview of the current alkali metals storage and handling arrangements, the condition of existing PFR facilities housing alkali metals, and improvement works undertaken to secure safe storage until a new alkali metals storage facility is operational. Immediate actions taken to improve current conditions included:
- Measures taken to prevent water pooling on or around alkali metal storage
- Additional environmental monitoring and control
- Revised inspections procedures
- Housekeeping improvements
NRS Dounreay provided an update on the progress made towards provision of a new, purpose built alkali metal store. It was noted that there have been delays on timescales for construction of the proposed new store (noting that timescales for final construction and transfer of drums/packages are well beyond the Improvement Notice due date).
The licensee provided an update on the alkali metal disposal strategy, progress towards which is tracked by regulatory issue RI-11140. A review of the baseline strategy considering only on-site disposal options is to commence at the beginning of the 2025/2026 financial year.
I conducted a plant walkdown of the PFR Turbine Hall, Steam Generator Building and Generator Transformer House (GTH), where I viewed the existing storage arrangements and the progress of the short-term improvement works. This was followed by a walkdown of the DN026 and DN029 facilities along with the Sodium Destruction Plant. During the course of the inspection I made some observations which were relayed to NRS for appropriate action.
Conclusion
Based on the evidence sampled related to the current storage arrangements, I judge that the licensee has adequately demonstrated control of risks associated with the short-term storage of alkali metals. I therefore assigned a GREEN rating to this inspection.
The Improvement Notice remains in place to secure the long-term storage of alkali metals, and the licensee assured me that delivery of the new store is high priority within the business. The development of a revise project schedule for long term safe storage of the material, as well as sufficient confidence that this will be delivered is required before the improvement notice can be closed out. I will continue to engage with the licensee to monitor progress through standing regulatory issue RI-11419.