New integral experiment on lead with DT neutron at JAEA/FNS

Kwon, Saerom; Ota, Masayuki; Ochiai, Kentaro; Sato, Satoshi; Konno, Chikara  

An integral experiment on lead which is a candidate material as a liquid breeder (such as LiPb), a neutron multiplier and a shield for ray in fusion blanket system with DT neutron source was performed at JAEA/FNS. However, the experimental data related to lower energy neutrons below a few keV could not be measured accurately, which suggested that the measured data might be affected by neutrons scattered in the concrete wall or other components in the experiment room (also known as background neutrons). Hence, we have carried out an integral experiment on lead with LiO blocks to reduce background neutrons and measured reaction rates of several reactions. We used the Monte Carlo radiation transport code, MCNP5-1.40 and the recent nuclear data libraries, ENDF/B-VII.1, JEFF-3.2, JENDL-4.0 and FENDL-3.0 (JEFF-3.1.1) for the experiment analysis. The calculated reaction rates with all of the nuclear data libraries related to higher energy neutrons above a few MeV agreed with the measured ones. However, the reaction rates related to lower energy neutrons were underestimated with the depth of the lead assembly. In this presentation, we also discuss these underestimation issues with the nuclear data of lead.