Application of laser fusion to the production of fissile materials

Calculations are made for the amount of ²³⁹Pu produced and the number of fast fissions occuring per 14 MeV neutron in a medium containing various concentrations of ²³⁸U, ²³⁹Pu, ¹⁶O, and ²³Na. Neutrons are assumed to be produced by a laser induced D + T fusion reaction and to interact with a blanket containing fertile materials where plutonium breeding occurs. Calculations show that in pure ²³⁸U the neutron multiplication factor is 4·6 and that 1·08 fast fissions occur per each D + T reaction. Assuming a neutron production rate of 3 × 10¹⁹ sec at E_n = 14 MeV and allowing for ²³Na cooling of the ²³⁸U blanket, the thermal energy generated is nearly 1000 MW, while the thermal value of the produced ²³⁹Pu is 4 times as large. Values are somewhat lower in cases where UO₂ is used in the blanket. Buildup of ²³⁹Pu in the blanket is considered and is found to have the effect of strongly increasing both the net ²³⁹Pu production and the thermal power generated.

Possibilities of using ²³²Th in the blanket and the D + D fusion reaction are also discussed and are found to be energetically inferior.