To examine the accuracy in the neutronics calculations for the Li/V-alloy blanket system without Be neutron multiplier, a fusion neutronics experiment on a Li/V-alloy assembly has been performed with a 14 MeV neutron source. Reaction rates and tritium production rates (TPRs) in the assembly were measured with activation foils and Li2CO3 pellets. The measured reaction rates sensitive to fast neutrons agreed almost within ~10 % with ones calculated by using the MCNP5 code, JENDL-3.3 library and JENDL dosimetry file 99. Though there appeared a possibility of a significant underestimation in the transport calculations for the energy range of <~4 keV due to nuclear data of vanadium, the measured TPR was consistent with the calculated one within ~8 %.