Determination of the Th-232(n,2n)Th-231 reaction rate in thorium oxide cylinder assembly under D-T neutron source

摘要

Aiming at verifying the evaluated cross-section of Th-232(n,2n) reaction for the conceptual design of thorium based subcritical blanket in fusion-fission hybrid reactor, an integral experiment was carried out using activation technique with D-T neutrons. Th-232(n,2n) reaction rates were measured in a ThO2 cylinder assembly with relative uncertainty of 8.0%. The experiment was simulated by MCNP code combining with ENDF/B-VII.0, ENDF/B-VII.1, CENDL-3.1 and JENDL-4.0 databases. The calculated Th-232(n,2n) reaction rates employing JENDL-4.0 show low discrepancy with the measured ones. The results could provide reference to the re-evaluation of Th-232(n,2n) cross-section and the design of fusion-fission hybrid reactor.