Measurement of the Neutron Spectrum in the 14MeV Neutron Driven Vanadium-Alloy Assembly by the Multifoil Activation Method

A neutronics benchmark experiment on vanadium-alloy was conducted by using the D-T neutron source facility of FNS/ JAERI. The neutron spectra in the vanadium-alloy assembly which was bombarded by D-T neutrons were measured by the multifoil activation - adjustment method. Reaction rates of 20 dosimetry reaction were measured. Neutron spectra were calculated by the MCNP-4A code with the JENDL Fusion File and FENDL/E-1.0 libraries. These calculated neutron spectra were used as initial guesses and adjusted by the SAND-II code with the measured reaction rates. Cross sections of the FENDL/A-2.0 library were used as detector response functions for the adjustment. The obtained adjusted spectra are consistent with the results of the on-line spectrum measurement. The evaluated cross section data of vanadium-alloy were validated on the comparisons between the calculated initial spectra and the adjusted spectra.