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Deteriorating asset condition poses acute risks, impeding hazard reduction and future site operations.

Conclusion
We explored with the witnesses the implications of assets’ condition for Sellafield Ltd’s plans to address hazards and clean up the site by 2125 and identified four areas of particular concern. Firstly – poor availability of assets has impeded Sellafield Ltd’s ability to address site hazards (such as retrieving waste from the older ponds and silos).60 The poor condition of its existing laboratory also poses ‘acute risks’ to the site’s ability to operate.61 Secondly, the failure of the ‘Replacement Analytical Project’ was in part caused by an inadequate understanding of the condition of the building being refurbished which led to the project’s difficulty being underestimated.62 The long–term strategy for providing analysis capabilities to the site became incoherent as a result.63 Thirdly, the ‘strategic tolerances’ for completing a set of activities inform the planning assumptions made for other facilities.64 For example, Sellafield Ltd told us that its need for certain types of analysis would be much lower once all the ‘Highly Active Liquor’ on the site has been turned into a glass–like substance – and this was a factor in its recent decision–making.65 In recent years, maintenance issues have seriously affected how much ‘liquor’ can be processed in this way.66 57 Qq 41–42 58 C&AG’s report, para 3.15 59 Q 49 60 Qq 12, 55 61 Q 66; C&AG’s report, para 2.17 62 Letter from the Group Chief Executive Officer of the Nuclear Decommissioning Authority relating to Public Accounts Committee’s visit to Sellafield, 17 March 2025, page 2 63 C&AG’s report, para 2.20 64 Q 48 65 Q 69; Letter from the Group Chief Executive Officer at the Nuclear Decommissioning Authority relating to the oral evidence session held on 20 March on Decommissioning Sellafield, 4 April 2025, page 3 66 Q 41; C&AG’s report, Figure 9 17 Fourthly, the deterioration in the overall condition of assets on the site was one of the factors that led Sellafield’s safety assurance team to conclude in 2022 that the site
Government Response

A response document is linked to this report, dated 18 September 2025. Response attribution to this conclusion has not been verified. Read the response document.

Addressee Bodies
HM Treasury
Timeline
Recommendation age 1.3 yr
Report published 04 Jun 2025