The Nuclear Decommissioning Authority, a non-departmental public body established in 2005, spent a total of £3.3bn in 2017-18, according to a National Audit Office report released yesterday.
Of this expenditure, £0.15 of every pound spent by the NDA in 2017-18 was on major projects at the Sellafield site.
The watchdog criticised the authority for wasting £586m on three major clean-up projects at Sellafield since 2012 before finding more cost-effective ways of carrying them out.
Although, the NAO acknowledged since it last reported on the Cumbrian site in 2015, the NDA and Sellafield Limited - the company that owns the plant - had made significant progress with programmes to reduce risk and hazard in legacy ponds and silos.
Amyas Morse, head of the NAO, said: “The improvements in reducing risk at Sellafield are encouraging, but the scale of the challenge is very great and the department could be doing more to support the NDA through better governance and oversight of performance.
“The NDA, for its part, needs to do a better job of explaining what progress it has made and what it will achieve over the next two to four years so parliament can hold it to account.”
The NDA has a clean-up mission lasting until 2120, with an estimated undiscounted cost of £121bn - Sellafield accounts for £91bn of this.
A Department for Business, Energy and Industrial Strategy spokesperson said: “The NAO review makes clear the improving performance of Sellafield Ltd and the significant progress and value for money it is delivering in ensuring the safety of the Sellafield site.
“The government will carefully scrutinise the NAO report and consider its recommendations.”
