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Dounreay - Inspection ID: IR-54016

Executive summary

Date(s) of inspection: 

May 2025

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-IN-23-3.

Subject(s) of inspection

  • COSHH - Rating: GREEN
  • LC 04 - 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). Following the issue of this Improvement Notice, NRS Dounreay established the Alkali Metal Storage Improvement Project to address the shortfalls highlighted. The project set a number of short and long-term actions including improvements which could be made to the current alkali metals storage arrangements at the PFR Turbine Hall (TH), Steam Generator Building (SGB) and Generator Transformer House (GTH). These improvements were intended to ensure safe storage while a new, dedicated storage facility could be designed and constructed. 

The Improvement Notice Schedule sets out six areas to be addressed. These are: 

  1. Ensure the adequacy of the storage arrangements of the alkali metals currently stored within the prototype fast reactor turbine and steam generator hall. 
  2. Ensure the storage arrangements have, and will continue to have, adequate barriers to prevent moisture ingress throughout their storage period. 
  3. Review the storage locations and controls to ensure that water is not making contact with, or pooling in the location of, the alkali metals storage arrangements. 
  4. Review the storage arrangements to ensure moisture control is given adequate consideration. 
  5. Review inspection and maintenance arrangements to ensure the storage locations and the containment barriers remain suitable to store the alkali metals throughout their storage period.
  6. Implement the aforementioned arrangements. 

Or take any equally effective measures to remedy the said contraventions.

In December 2024, I led an alkali metals themed inspection which focused primarily on the short-term improvements to the current storage arrangements. NRS Dounreay also provided an update on the longer-term project delivery. 

I led a follow up inspection in May 2025. During this inspection, I conducted a walkdown of the current storage areas including the TH, GTH and SGB as well as the current DN026 structure which will be refurbished into the new alkali metal storage facility. NRS presented its argument in support of lifting the Improvement Notice, addressing each area in turn, identifying actions which are to be completed by the Notice deadline in June 2025 as well as a suite of longer-term actions which will take the project through to completion by the end of 2026. Due to the project lifecycle extending beyond the Improvement Notice deadline, the aim of this inspection was to:

  • Confirm that sufficient action has been taken to support closure of the Improvement Notice; and
  • Seek confidence from NRS Dounreay that, should the Improvement Notice be lifted, the project will continue to receive adequate support, funding and resource such that it can be taken through to fruition. 

Conclusion

Based on the evidence sampled during the inspection I judge that the short-term improvements made to the current storage arrangements are adequate to ensure safe storage of the material until the new store is available. Based on the evidence provided by NRS Dounreay, I am satisfied that the project will continue as planned, beyond the expiry date of the Notice and will receive the support necessary to ensure that the new storage facility is built and operational in a timely manner, such that safe storage can be provided. I therefore rate this inspection as GREEN. 

Based on the evidence provided as well as the confidence taken during the regular project update meetings I am satisfied that the intent of the Improvement Notice has been met and therefore I make the following recommendations:

  • I recommend that the Improvement Notice IN-23-3 be lifted prior to the deadline of 27th June 2025, subject to ONR governance. 
  • I recommend a new Level 3 Regulatory Issue be raised to track project progress through to construction and operation of the new storage facility.
  • I recommend that Regulatory Issue RI-11419 be closed. The outstanding actions should be captured within the new Level 3 Regulatory Issue.