Sellafield's race against time: nuclear waste clean-up not going quickly enough, PAC warns

4th June 2025

Report highlights latest picture on delays and cost rises in c.£136bn 100-year nuclear decommissioning project.

The retrieval of waste from ageing buildings at the most hazardous nuclear site in the UK is not happening quickly enough.

In its report on decommissioning Sellafield, the Public Accounts Committee (PAC) warns that the estimated £136bn cost of the project would rise even more if work is further delayed, while expressing scepticism as to whether or not recent signs of improvement in performance could represent another false dawn.

The PAC found in 2018 that government needed a firmer grip on Sellafield's nuclear challenges, and now warns that not enough progress has been made in addressing its most significant hazards. One building, the Magnox Swarf Storage Silo (MSSS), has been leaking radioactive water into the ground since 2018 - the PAC calculates, at current rates, enough to fill an Olympic swimming pool roughly every three years. The Nuclear Decommissioning Authority (NDA) accepts this leak is its "single biggest environmental issue", but that the radioactive particles are "contained" in the soil and do not pose a risk to the public.

The PAC's report finds that Sellafield Ltd has missed most of its annual targets for retrieving waste from several buildings on the site, including the MSSS. The PAC's inquiry heard that the MSSS is the most hazardous building in the UK, and as a result of Sellafield Ltd's underperformance will likely remain extremely hazardous for longer. The report seeks answers from Government on how it will hold the NDA and Sellafield Ltd to account in ameliorating the site's greatest hazards.

As well as safety concerns, the PAC further warns of the impact that delays in the programme have on costs. In the long-term, waste will need to be stored in an underground Geological Disposal Facility (GDF) capable of storing it for thousands of years. The PAC finds that the date for the GDF has slipped from 2040 to the late 2050s, with every decade of delay meaning Sellafield could need to construct another storage building, each costing £500m-£760m. The GDF project is still at an early stage, with sites considered in Cumbria and Lincolnshire - though the PAC understands that Lincolnshire County Council has recently announced it is likely to withdraw.

The report highlights some recent signs of improvement in Sellafield’s delivery, with more emphasis put on planning in how it works with contractors and most recently-started projects being delivered in line with their business cases as a result. However, the report highlights the example of one of Sellafield’s project to refurbish an onsite lab so it could continue analysing waste samples - essential for safety.

The report finds that this very poorly managed and now-paused project has seen £127m wasted. Its failure, which resulted from a lack of understanding of what physical state its labs were in, and from not doing the right remedial work to address their deterioration, illustrates the need to improve asset management at Sellafield. The report urges Sellafield Ltd to explain how it is addressing the deteriorating condition of its assets, which its safety experts have warned is making the site increasingly unsafe.

The PAC’s report also finds indications of a sub-optimal culture at the site, with concerns raised in the report given that the exceptionally hazardous nature of many of Sellafield's activities means that it is imperative that all employees and contractors on the site feel able to raise any concerns that they have without fear of consequences. The PAC is aware that the NDA paid £377,200 in 2023-24 to settle employment-related claims.

Further, the PAC previously noted that non-disclosure agreements have been used elsewhere in the public sector to cover up failure. The report finds that Sellafield Ltd has signed 16 non-disclosure agreements in the last three years. It further seeks publication from the NDA of information around the prevalence and perception of bullying and harassment in its annual report.

Chair comment
Sir Geoffrey Clifton-Brown MP, Chair of the Committee, said: "The intolerable risks presented by Sellafield’s ageing infrastructure are truly world-class. When visiting the site, it is impossible not to be struck by the fact that one can be standing in what is surely one of the most hazardous places in the world. This is why we expect Sellafield’s management of its assets, and the delivery of the project to decommission it, to be similarly world-class. Unfortunately, our latest report is interleaved with a number of examples of failure, cost overruns, and continuing safety concerns. Given the tens of billions at stake, and the dangers onsite to both the environment and human life, this is simply not good enough.

"As with the fight against climate change, the sheer scale of the hundred-year timeframe of the decommissioning project makes it hard to grasp the immediacy of safety hazards and cost overruns that delays can have. Every day at Sellafield is a race against time to complete works before buildings reach the end of their life. Our report contains too many signs that this is a race that Sellafield risks losing. It is of vital importance that the Government grasp the daily urgency of the work taking place at Sellafield, and shed any sense of a far-off date of completion for which no-one currently living is responsible. Sellafield’s risks and challenges are those of the present day. There are some early indications of some improvement in Sellafield’s delivery which our report notes. Government must do far more to hold all involved immediately accountable to ensure these do not represent a false dawn, and to better safeguard both the public purse and the public itself."

Read the full report HERE

Source
https://committees.parliament.uk/committee/127/public-accounts-committee/news/207132/sellafields-race-against-time-nuclear-waste-cleanup-not-going-quickly-enough-pac-warns/