Transmutation process for minor actinide nuclide

Among minor actinide nuclides separated from spent fuels, Neptunium (Np) is added to reactor core fuels in an FBR type reactor, and americium (Am) and rare earth element are added to one or both of a radial blanket and an axial blanket, and they are burnt. In a case of a plutonium combustion reactor, not a plutonium breeding reactor, Am and rare earth elements are added to one or both of a radial shielding and an axial shielding instead of the blankets, and then they are burnt. In the present invention, since Np is thus added to the reactor core fuels, and Am (and curium, Cm) and rare earth elements are added to the blankets or the shieldings, minor actinide nuclides having a long half-life taken out from spent fuels can be transmutated by burning without burden of separating minor actinide nuclides and rare earth elements. (T.M.)