Transient-temperature behavior following a step change in internal heat generation has been analyzed to determine the power generation in the Battelle Shielding Facility fission plate. The fission plate is employed for shielding studies as a radiation source with a fission energy distribution. The plate is a 28-in. diam, 0.0199-in. thick uranium disk containing 3741 gm of uranium enriched to 93.14% in the uranium-235 isotope. It is plated with 0.0007 in. of nickel and clad with 0.025 in. of aluminum on each side and is in intimate contact with a 0.25-in. thick aluminum plate on one side. Ceramic spacers provide airgap insulation of the fission-aluminum plate combination from the surrounding media. Resistance thermometers were employed to observe the transient-temperature behavior following a step change in the internal heat generation in the plate for fission heating and for cooling tests. The cooling curve data were strictly exponential and rendered a decay constant of 0.0517 min−1 which was utilized, along with the physical constants of the assembly, to render a solution to the transient-heating equation and an estimated power of 25.0 ± 0.6 watts.