JV with Amentum will build UK treatment facility for sodium coolant
UK-based Cavendish Nuclear and its US-based partner Amentum have been awarded the next phase of work by the Japan Atomic Energy Agency (JAEA) to support the decommissioning of the Monju prototype fast reactor in Fukui Prefecture, western Japan.
A statement said their joint venture, Alkali Metal Processing, will build a UK facility to treat the reactor’s sodium coolant, converting it into sodium hydroxide for industrial reuse.
The contract follows a design and engineering phase and draws on experience from decommissioning the UK’s Dounreay prototype fast reactor, which shares design similarities with Monju.
Cavendish was first awarded work on the Monju decommissioning project in 2019, drawing on its UK expertise in dismantling fast reactors.
Japan’s regulator approved a 30-year decommissioning roadmap in March 2018.
Monju, a 246-MW sodium-cooled fast breeder reactor, was designed to run on uranium-plutonium mixed fuel and generate more fissile material than it used.
Although it achieved first criticality in 1994, it has been largely idle since a 1995 accident involving a sodium leak and fire.
The government decided in 2016 to shut the facility for good, with dismantling costs put at about $3.2bn (€2.7bn) by Japanese media.
