Benchmark experiments on breeding properties of thorium

摘要

Thorium is a fertile element that can be applied in the conceptual blanket design of a fusion-fission hybrid reactor. It is essential to validate Th-232 nuclear data and obtain the breeding properties of macroscopic thorium assemblies by conducting integral neutronics benchmark experiments. The thorium assemblies with a D-T fusion neutron source consist of a polyethylene shell, depleted uranium shell, and thorium oxide powder cylinder. The Th-232 (n, gamma), Th-232 (n, f), and Th-232 (n, 2n) reaction rates in the assemblies are measured by ThO2 foil activation technique. The experimental uncertainties are about 3.1% for Th-232 capture rates, 5.3-5.5% for Th-232 fission rates, and 6.8-7.0% for Th-232 (n, 2n) reaction rates. From Th-232 reaction rates, the fuel and neutron breeding properties of thorium under different neutron spectra are obtained and compared. The experiments are simulated by using the MC code with different evaluated data. The ratios of calculation to experimental values for the reaction rates are analyzed.