Nuclear data benchmark experiment on lead with DT neutrons

Kondo, Keitaro; Ochiai, Kentaro; Suzuki, Chihiro*; Yagi, Takahiro*; Onishi, Seiki; Takakura, Kosuke; Sato, Satoshi; Abe, Yuichi; Konno, Chikara  

Lead is considered as one of the candidates of the neutron multiplier in the blanket of a fusion reactor. A benchmark experiment with a DT neutron source aiming at the accuracy validation of nuclear data evaluated for lead was thus carried out in the Fusion Neutronics Source facility of Japan Atomic Energy Agency. A lead cubic assembly of 45 cm in thickness was constructed, and the reaction rate measurement with activation foils (In, Ni, Al, Nb, Zr) of which the threshold energy is above 0.3 MeV and the neutron spectrum measurement with an NE213 detector inside the assembly was conducted. We found that the calculation with JENDL-3.3 showed the very large underestimation of the neutron flux above 10 MeV as increasing of depth, and its magnitude was approximately 50% at 40 cm depth. On the other hand, the calculations with ENDF/B-VII.0 and JEFF-3.1 reproduced the experimental values comparatively well.