A new-design space-saving storage rack has begun receiving Advanced Gas-cooled Reactor used fuel at a storage pond attached to the closed Thorp reprocessing plant on the Sellafield site in the UK. The new 63-can rack was developed to increase the storage capacity of the receipt and storage ponds at the Thermal Oxide Reprocessing Plant (Thorp) plant, which ceased operation in 2018.
Announcing the closure of the facility, Sellafield Ltd and the UK Nuclear Decommissioning Authority (NDA) said Thorp would continue to serve the UK until the 2070s as a storage facility for used fuel. The plant, opened in 1994, was one of only two commercial nuclear fuel reprocessing plants in the world (the other being Orano’s La Hague in France).
Before its closure, Thorp reprocessed more than 9000 tonnes of fuel from 30 customers in nine countries around the world and generated an estimated £9bn ($11.5bn) in revenue. Thorp is one-third of a mile long and dominates a huge central strip of the Sellafield site. It is the largest structure on the site and cost £1.8bn to build, “paid for by its future customers”. The decision to cease reprocessing was taken in 2012 “in response to a significant downturn in demand”.
The new storage rack is taller but with a smaller footprint than the previous design. Each rack can store 63 fuel cans compared with the existing storage compartments that can hold up to 20 fuel cans. Fuel that was already being stored in the pond is being transferred into the new storage racks which will be used for all future fuel deliveries.
Use of the new racks means Sellafield can safely store all the fuel expected from the UK’s currently operational nuclear power stations. Without the rack, a new storage pond would have to be built, potentially costing billions of pounds. Sellafield said the rethink was required because Thorp needs to store more fuel than was previously expected because the UK no longer reprocesses used fuel, but stores it underwater instead, pending final disposal.
The rack, which has been 16 years in the making, weighs 7 tonnes and is 5.5 metres tall. These stainless steel containers are being built by a consortium of Cumbrian manufacturers and Stoke-based Goodwin International. Between them, they will manufacture 160 racks. Another 340 racks will be needed in the future. It represents a key contract for Carlisle-based Bendalls Engineering and Workington’s West Cumbria Engineering, who head up the Cumbria Manufacturing Alliance making half of the racks.
Roddy Miller, Sellafield Ltd’s Nuclear Operations Director said Sellafield had been serving the UK nuclear industry since the 1940s. “These days, our job is to create a clean and safe environment for future generations by safely managing our nuclear legacy,” he noted. “This includes receiving and storing the UK’s spent nuclear fuel, helping EDF Energy to continue generating low carbon electricity for homes and businesses.”
He added: “Since the change of approach to managing spent fuel, it was clear we would need to innovate to be able to safely store everything we need to in the Thorp pond. These racks will increase fuel capacity from 4,000 tonnes to 6,000 tonnes, meaning we can accommodate all current and future arising, negating the need for a new storage facility.”
Transfers of fuel from the old containers into the new racks started during the summer. Operators who previously fed fuel into the reprocessing system are now placing fuel into the new racks. Because fuel will be stored for longer than was originally intended, the pond has required other alterations including raising the pH level to avoid corrosion and installing new cooling capacity.
Researched and written by Judith Perera
