Measurements and analyses of uranium reaction rates on a depleted uranium shell with D-T neutrons

Abstract

Aiming at checking the conceptual design of the subcritical reactor, an experiment using activation technique was carried out on a depleted uranium shell of R19.4/30.0 cm with D-T neutrons. The 6 depleted uranium foils were activated at 90° with respect to the incident D beam in the shell, and distributions of 238U (n, γ) reaction rates, 238U (n, f) reaction rates, 238U (n, f) reaction rates and 238U (n, 2n) reaction rates were obtained, by measuring characteristic γ rays generated by corresponding uranium reactions. The relative uncertainties are 3.6%–3.7% for 238U (n, γ) reaction rates, 5.1%–5.9% for 238U (n, f) reaction rates and 238U (n, f) reaction rates, and 4.3%–4.7% for 238U (n, 2n) reaction rates. The experiment was simulated using MCNP5 code with ENDF66c library, and the calculation-to-experiment ratios are 0.972–1.034 for 238U (n, γ) reaction rates, 0.983–1.058 for 238U (n, f) reaction rates and 238U (n, f) reaction rates, and 0.979–1.019 for 238U (n, 2n) reaction rates.