Sellafield Ltd reported on 8 October 2026 that teams had completed the bulk removal of one of its oldest legacy inventories: radioactive BUTEX liquor, a byproduct of the site's first reprocessing operations in the 1950s, which had stayed for decades in the oldest tanks of the Highly Active Liquor Evaporation and Storage (HALES) plant. The company said the original plans had been to leave the liquor in the tanks until operations there ended, and that finding alternative storage on the busy site had raised additional issues. Around 110m³ needed to be moved.

The oldest tanks had not seen a transfer in almost 20 years, prompting concern that the systems involved might no longer work. Teams updated ventilation, planned the work and secured permissions through engagement with the Office for Nuclear Regulation and the Environment Agency, Sellafield said, beginning with a small transfer before larger-scale operations. The company said the full job was expected to take more than a year but took months, with 2,250 operating cycles moving 40 litres at a time.

Removing the self-heating liquor reduced the heat load on some of HALES' oldest assets, according to the company. The liquid is to be vitrified, mixed with glass for safer long-term storage, and will stay in new tanks until then. HALES head of operations Chris Bone said that a few years ago there was real uncertainty about whether this could be done.