Benchmarking of evaluated nuclear data for iron by a TOF experiment with slab samples

Abstract

In order to validate the evaluated nuclear data of iron, neutron leakage spectra in the range from 0.8 to 15 MeV from natural iron slab samples were measured by time-of-flight technique at 60° and 120°, the measurements were performed at China Institute of Atomic Energy (CIAE) using a D-T neutron source, the slab thicknesses were chosen to be 5 cm, 10 cm and 15 cm, corresponding to 1.08, 2.16 and 3.24 mean free paths for 14.5 MeV neutrons, respectively. Theoretical calculations were carried out by Monte Carlo neutron transport code MCNP-4C, using the evaluated nuclear libraries of iron from the CENDL-3.1, ENDF/B-VIII.0, JENDL-4.0, JEFF-3.3, and TENDL-2017. The experimental results were compared with the corresponding calculated ones. From the comparison, it was found that: (1) In the 12–15 MeV range, the results with the ENDF/B-VIII.0 library well reproduce the experimental ones at both 60°and 120°, but those with the JENDL-4.0, JEFF-3.3 and TENDL-2017 libraries are underestimated, especially at 120°; (2) In the 8.5-12 MeV energy range, the calculated neutron spectra with the TENDL-2017 library are underestimated by more than 35%, but those with the JENDL-4.0 library are overestimated around 20%.