Measurement of reaction rates in Li/V-alloy assembly with 14 MeV neutron irradiation

Tanaka, Teruya*; Sato, Satoshi; Kondo, Keitaro; Ochiai, Kentaro; Murata, Isao*; Takakura, Kosuke; Sato, Fuminobu*; Kada, Wataru*; Iida, Toshiyuki*; Konno, Chikara  ; Muroga, Takeo*

Irradiation experiments of 14 MeV neutrons have been performed on a Li block assembly of 46 51 51 cm with a 5 cm thick V-alloy layer inside to examine the accuracy of neutronics calculations for the Li/V-alloy blanket design. Foils of Nb, Ni, In and Au for reaction rate measurements of Nb(n,2n)Nb, Ni(n,p)Co, In(n,n')In, Au(n,)Au reactions and Li enriched (Li: 95.5%) and Li enriched (Li: 99.9%) LiCO pellets for tritium production rate measurements were installed in the assembly. Results of the measurements were compared with those of calculations with MCNP5, JENDL-3.3 and JENDL/D-99. The comparisons for the reaction rates in the Nb, Ni and In foils indicate that measurements and calculations of the fast neutron transport are consistent almost within 10%. In the comparison for the reaction rates in the Au foils, the underestimation of 15% was found at a surface of the V-alloy layer. There is a possibility that this is due to the elastic scattering cross section of V around 4 keV as previously reported. The comparisons for tritium production rates in the Li enriched and Li enriched LiCO pellets indicate that calculated rates were larger than results of the measurements by 2-8% and 1-4%, respectively.