Energy Dependence of Plutonium and Uranium Average Fragment Total Kinetic Energies

A simple method has been developed to extrapolate measured first-chance fission-product average fragment total kinetic energies to higher energies where second-, third-, and fourth-chance fission are of importance. A prediction is made for the average total kinetic energy of Pu-239(n,f) and U-235(n,f) fission fragments up to a neutron energy of 20 MeV. These predictions will be tested over the next few years by the SPIDER collaboration at Los Alamos National Laboratory.