Engineering news
A four year study into nuclear waste has resulted in a breakthrough that the Nuclear Decommissioning Authority has said will save the taxpayer hundreds of millions of pounds.
The research focused on the chemical behaviours of the Intermediate Level Waste (ILW) stored in the Magnox Swarf Storage Silo (MSSS) – one of the UK’s most hazardous buildings, and a priority for the Nuclear Decommissioning Authority (NDA) to clean-up. It was thought a 22-step mechanical treatment and encapsulation process would be needed to manage and ultimately dispose of the ILW stored in silos constructed over 50 years ago.
However, the study’s findings suggest an alternative three step solution that stores the waste ‘raw’ with concrete grout inside a shielded container is possible. The process would speed up decommissioning of the silo by several years and provide huge savings.
The waste package would be suitable for interim storage at Sellafield and then, once grouted, final disposal in a UK geological disposal facility. The technique could also be applied to other redundant nuclear facilities in the UK and around the world, said the NDA.
The four year study focused on the corrosion behaviours of magnesium and uranium and shed new light on the hazards these materials pose to people and the environment in the long term.
The NDA called the research a “genuinely exciting development”. The approach will also reduce the ‘secondary wastes’ created during the treatment phase, resulting in an estimated 10% fewer waste packages being produced during the decommissioning of MSSS.
Dr Adrian Simper, strategy and technology director for the NDA, 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.”
The study was led by the NDA, Sellafield Ltd and the National Nuclear Laboratory, with academics from the universities of Bristol, Leeds and London South Bank.
The Magnox Swarf Storage Silo (MSSS) was built in the 1960s to receive spent fuel from nuclear plants all around the UK so it could be recycled. However a higher than expected rate of power generation by Magnox reactors at the time meant more spent fuel than could be reprocessed arrived at Sellafield.
Fuel cladding, known as swarf, has been stored under water in the 22 individual compartments within the silo. A project to pump out the radioactive water has been running for the last five years.