UK Inquiry Tracker

Decommissioning Sellafield

Public Accounts Committee Closed Inquiry

Opened: 31 Oct 2024 Closed: 21 Aug 2025 Parliament page

The Sellafield nuclear site closed in 2003, having operated since 1950. Work began to decommission the site in 2005. Highly hazardous materials are stored there from across the UK’s nuclear industry, and it holds a legacy of contaminated buildings, untreated waste and ageing facilities. The Nuclear Decommissioning Authority (NDA), the … Read more The Sellafield nuclear site closed in 2003, having operated since 1950. Work began to decommission the site in 2005. Highly hazardous materials are stored there from across the UK’s nuclear industry, and it holds a legacy of contaminated buildings, untreated waste and ageing facilities. The Nuclear Decommissioning Authority (NDA), the public body in charge of Sellafield, expects full site remediation will take until 2125. The forecast future cost of decommissioning Sellafield, after adjusting for inflation, was £136bn in March 2024 – this is 18.8% higher than it was in March 2019. The Committee last reported on Sellafield in 2018, when it found that Government needed a firmer grip on the challenges the site presents. The report recognised that significant milestones had been met in reducing risk at the high hazard facilities at Sellafield, it found that most major projects there were significantly delayed, with expected combined cost overruns at the time of £913m. Earlier that same year, the Committee scrutinised the procurement and management of the contract to clean up the Magnox nuclear reactor and research sites, finding that costly mistakes in these areas caused untold reputational damage to the NDA. The National Audit Office (NAO) found in 2024 that, despite progress having been made since 2018 on areas including hazardous waste retrieval and storage, value for money is not yet being achieved at Sellafield. The report the need to address the deteriorating condition of key assets, the lack of a comprehensive measure to assess progress in reducing risk, and large projects still being delivered later than planned and at higher cost. Based on the NAO report, the Committee will hear from senior officials at the NDA, DESNZ and Sellafield Ltd on subjects including: - Risk reduction and progress to date in managing risk; - Progress towards decommissioning with ongoing and future costs; and - Operational effectiveness and organisational culture. Please look at the requirements for written evidence submissions and note that the Committee cannot accept material as evidence that is published elsewhere. If you have evidence on these issues please submit it here by 23:59 on Thursday 6 March 2025. Show less

9 Recommendations

23 Conclusions

1 Report

1 Oral session

7 Letters

1 Event

Activity timeline 10 events

8 Jan
2026

Correspondence

Letter from the Interim Permanent Secretary at the Department for Energy Security & Net Zero relating to Decommissioning Sellafield, 12 Dec…

8 Jan
2026

Correspondence

Letter from the Group Chief Executive of the Nuclear Decommissioning Authority relating to Decommissioning Sellafield, 12 December 2025

15 Dec
2025

Correspondence

Letter from the Chief Executive Officer of Sellafield Ltd relating to recommendations of the Committee’s Twenty-eighth Report on Decommissi…

24 Nov
2025

Correspondence

Letter from the Chair to the Permanent Secretary at the Department for Energy Security and Net Zero, the Group Chief Executive Officer at t…

18 Sep
2025

Report published

Treasury minutes: Government response to the Committee of Public Accounts on the Twenty-eighth report from Session 2024-26

4 Sep
2025

Correspondence

Letter from the Chief Executive Officer at Sellafield Limited relating to the 28th Report of Session 2024-25, Decommissioning Sellafield, R…

4 Jun
2025

Report published

28th Report - Decommissioning Sellafield

24 Apr
2025

Correspondence

Letter from the Group Chief Executive Officer at the Nuclear Decommissioning Authority relating to the oral evidence session held on 20 Mar…

7 Apr
2025

Correspondence

Letter from the Group Chief Executive Officer of the Nuclear Decommissioning Authority relating to Public Accounts Committee’s visit to Sel…

20 Mar
2025

Oral evidence

Oral evidence session

Oral evidence sessions 1 session

20 Mar 2025

View on parliament.uk

Clive Maxwell · Department for Energy Security and Net Zero David Peattie · Nuclear Decommissioning Authority Euan Hutton · Sellafield Ltd Kate Bowyer · Nuclear Decommissioning Authority Lee McDonough · Department for Energy Security and Net Zero

Reports 1 report · click to expand

Title	HC No.	Published	Items	Response
28th Report - Decommissioning Sellafield	HC 363	4 Jun 2025	32	Response document linked

Recommendations & Conclusions

32 results

2 Recommendation

28th Report - Decommissioning Sell…

Publish medium-term targets for Sellafield's key decommissioning activities and report annual progress.

The targets set for Sellafield Ltd neither support DESNZ and the NDA in holding it to account for poor performance, nor allow Sellafield Ltd to demonstrate it is making meaningful progress towards addressing the site’s hazards. In recent years, Sellafield … Read more

HM Treasury

Decommissioning Sellafield

Activity timeline 10 events

Oral evidence sessions 1 session

Reports 1 report · click to expand

Recommendations & Conclusions

Publish medium-term targets for Sellafield's key decommissioning activities and report annual progress.

Require Sellafield Ltd to update Committee on plutonium analysis and alternative project costs.

Require Sellafield Ltd to explain actions addressing deteriorating asset condition and maintenance team productivity.

Publish financial model scenarios to reduce NDA estate lifetime decommissioning costs, including funding constraints.

Publish bullying/harassment prevalence, staff survey results, and reporting effectiveness metrics in NDA Annual Report.

Committee took evidence on the decommissioning of the Sellafield site.

Magnox Swarf Storage Silo's radioactive leak persists, with emptying delayed significantly until 2054-2059.

Sellafield Ltd consistently misses waste retrieval and vitrification targets since 2020 due to various issues.

Plutonium management at Sellafield shows improvement, with long-term strategy to reduce risks by 2060.

Sellafield Ltd consistently underperforms against strategic waste processing targets, impacting wider site cleanup plans.

Sellafield Ltd plans significant acceleration of waste retrieval, requiring substantial capability development over next few years.

Efficient waste retrieval demands constant iteration, strong performance culture, and sophisticated, transparent target setting.

Major project delays and costs at Sellafield significantly escalated since 2018 due to poor planning.

Recent major project delivery at Sellafield shows tangible signs of improvement, with several projects on track.

New Programme and Project Partners (PPP) model improves major project delivery at Sellafield.

Improved project planning and robust assurance processes contribute to better delivery outcomes at Sellafield.

NDA and Sellafield Ltd actively share project learning and best practice group-wide.

Replacement Analytical Project faced significant cost increases and delays due to inadequate planning.

Sellafield Ltd adopted a new, cheaper plan for analytical services despite long-term uncertainties.

Significant financial waste on previous projects indicates slow learning of lessons at Sellafield.

Sellafield's century-long decommissioning plan faces urgent race against ageing assets.

Increasing maintenance backlog and unknown asset conditions negatively impact Sellafield operations.

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

Sellafield decommissioning costs have significantly risen, potentially compromising long-term value for money.

Funding constraints force difficult decisions, risking long-term costs and facility obsolescence.

Department relies on NDA boards for resource allocation; lacks recent greenfield cost analysis.

UKGI's role in NDA oversight remains unconvincing and unclear.

Geological Disposal Facility project experiences significant delays and slow progress.

Government must improve valuing whistleblowers, addressing Sellafield mistreatment allegations.

Sellafield believes its safety reporting processes are robust and effective.

Sellafield Ltd uses NDAs and makes significant special payments for employment claims.

Sellafield's workplace culture demonstrates improvement through new 'Speak Up' initiatives.

Correspondence 7 letters