The benchmark experiment on slab beryllium with D–T neutrons for validation of evaluated nuclear data

• Evaluated data for beryllium are validated by a high precision benchmark experiment.
• Leakage neutron spectra from pure beryllium slab are measured at 61° and 121° using time-of-flight method.
• The experimental results are compared with the MCNP-4B calculations with the evaluated data from different libraries.

Beryllium is the most favored neutron multiplier candidate for solid breeder blankets of future fusion power reactors. However, beryllium nuclear data are differently presented in modern nuclear data evaluations. In order to validate the evaluated nuclear data on beryllium, in the present study, a benchmark experiment has been performed at China Institution of Atomic Energy (CIAE). Neutron leakage spectra from pure beryllium slab samples were measured at 61° and 121° using time-of-flight method. The experimental results were compared with the calculated ones by MCNP-4B simulation, using the evaluated data of beryllium from the CENDL-3.1, ENDF/B-VII.1 and JENDL-4.0 libraries. From the comparison between the measured and the calculated spectra, it was found that the calculation results based on CENDL-3.1 caused overestimation in the energy range from about 3–12 MeV at 61°, while at 121°, all the libraries led to underestimation below 3 MeV.