The decision ends British involvement in the development of fast-breeder reactors, which unlike conventional reactors "breed" their own plutonium fuel.
Japan and France remain the world's only users of fast-breeder reactors which produce more plutonium than they consume.
A fast-breeder reactor takes spent nuclear fuel and processes it for reuse as fuel or weapons.
More recently fast-breeder reactors fuelled with a mixture of plutonium and uranium have been developed by some countries.
In contrast, the plutonium fuel used in fast-breeder reactors could possibly go supercritical during a core collapse meltdown.
Even optimistic officials think it will take three years to restart its fast-breeder reactor, where a leak occurred in December.
The Japanese government has announced that it will support the next stage of development of a fast-breeder nuclear reactor.
Liquid sodium is used as a coolant for fast-breeder nuclear reactors, which produce more plutonium than they consume.
One of the most significant will be a look at the next generation of fast-breeder nuclear reactors.
In particular they'd sought the promise of fast-breeder nuclear reactors.