ESA to fund its own RTG studies? Options

[Paolo]

according to Flight International UK could use plutonium in space nuclear power demonstration

[Holder of the Tw...]

Plutonium 238 can be produced in usable purity in two different ways. Separate out neptunium 237 from spent reactor fuel. Place this in a reactor to expose it to neutrons. The Np-237 atoms that capture a neutron will either fission or form Np-238. Np-238 will decay to Pu-238 in short order. There will always be a little bit of Pu-239 contamination from double neutron capture. This is the standard process.

You can also make it from exposing americium 241 to neutrons, producing Am-242, which beta decays to Curium 242, then alpha decays to Pu-238. This method requires a high flux of neutrons.