5
Publish financial model scenarios to reduce NDA estate lifetime decommissioning costs, including funding constraints.
Conclusion
DESNZ is not doing enough to ensure that long–term value for money is achieved from decommissioning the Sellafield site. The cost of decommissioning Sellafield continues to grow – notwithstanding the billions spent on the site every year. The NDA’s tight funding setttlement for 2025–26 will mean more work slips into future years, increasing the long–term cost to the taxpayer. We were disappointed the Department sought to place the 5 onus for achieving value for money entirely on the NDA and Sellafield Ltd: as the NDA’s sponsor, it has an important role to play as well. We are still not convinced that UK Government Investments plays any useful role in the NDA’s governance that the Department could not fulfil itself. We would also have expected the Department to take a more active interest in the relative cost of different options for cleaning up NDA sites so it fully understands the cost implications of its current policy of full site remediation. Meanwhile, the date when the NDA will be able to store waste permanently in a Geological Disposal Facility (GDF) has slipped from 2040 to the late 2050s, even though the programme is still only at an early stage. For every decade of delay, Sellafield could need to construct another storage building (each costing £500 million–£760 million) and would incur higher operating costs. recommendation The Nuclear Decommissioning Authority and Sellafield Ltd should use their existing long–term financial models to produce and publish a range of scenarios, giving more insight into how government can reduce the lifetime decommissioning cost of the NDA estate. This should include an assessment of the cost (on both a discounted and undiscounted basis) if government funding for the NDA is constrained at current levels in all future years.
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.
Source
Committee
Public Accounts Committee
Inquiry
Decommissioning Sellafield
Report
28th Report - Decommissioning Sellafield
04 Jun 2025
HC 363
Addressee Bodies
HM Treasury
Timeline
Recommendation age
1.3 yr
Report published
04 Jun 2025