Measurements of Pu and U²³⁵ Fission Rates in Water—Uranium Reactor Spectra

Measurements of Pu²³⁹ and Pu²⁴¹ fission rates relative to U²³⁵ have been made in 1.3% enriched uranium metal fueled lattices. Results were obtained in lattices having 0.387-in. diameter rods and water-to-uranium ratios of 2.35:1 or 1:1. The measurements are compared with a calculational model and the agreement is considered good.