Sellafield has hailed a “revolutionary” breakthrough that should accelerate decommissioning and could slash costs by up to £1bn.

Scientists studying intermediate-level waste (ILW) in one of the site’s historic waste stores have unearthed previously-unknown information about the material’s long-term behaviour.

The discovery has allowed the site to take a simplified approach to the packaging and disposal of ILW that could, Sellafield argues, see significant reductions in the timescales and costs. 

The new approach could also be applied to other redundant nuclear facilities. 

The research focused on the chemical behaviours of ILW stored in the Magnox Swarf Storage Silo, which was built in the 1960s and has been prioritised for clean-up by the Nuclear Decommissioning Authority (NDA). 

Previously, a 22-step mechanical treatment and encapsulation process was thought necessary. 

But the study’s findings support an alternative three-step solution, which stores the waste in a raw form without the need for a downstream treatment and encapsulation.

This produces a waste package suitable for interim storage at Sellafield for decades with only a simple cap required for final disposal in an underground repository. 

Switching to this new method should speed up decommissioning of the silo by four years, provide huge savings and help answer criticisms levelled at Sellafield by the Public Accounts Committee and others over the rising costs of decommissioning. 

Dr Adrian Simper, the NDA’s strategy and technology director, said: “This research has delivered the underpinning to what could be a paradigm shift in the management of nuclear waste. 

“Having a greater understanding of the long-term behaviour of this material allows us to design a truly fit-for-purpose approach to its management and disposal. 

“To be able to deliver a technical solution to ILW that not only offers a safe and secure route but also the possibility of a quicker and cheaper alternative to current technology is genuinely exciting.” 

The four-year study was led by the NDA, Sellafield Ltd and the National Nuclear Laboratory, with academics from UK universities. 

It focused on the corrosion behaviours of magnesium and uranium, and shed light on the hazards these materials pose to people and the environment in the long term. 

Its conclusions suggest that previous estimates about the level of treatment required to form protection against the dangers posed by these waste were overly conservative. 

Another benefit of the alternative approach is a reduction in secondary wastes created during the treatment phase.