Fusion neutron source: potential in the production of 237Np and 231Pa for improving the proliferation protection of nuclear materials

The paper evaluates the capability of fusion facilities to produce fissionable materials with the maximum content of the artificial isotopes 237Np and 231Pa. In particular, the paper investigates the effects of the 237Np or 231Pa production zone thickness and the composition of the next zone on the production rates of fissionable isotopes under neutron irradiation of 238U or 232Th. It is demonstrated that relatively thin (about 10 cm thick) uranium or thorium zones should be applied for the production of 237Np and 231Pa. Also, it is revealed that incorporation of 237Np or 231Pa production zones into the blanket module of an International Thermonuclear Experimental Reactor type of fusion facility leads to reduced attenuation of the fast-neutron flux by the blanket module.