Measurement of the selected spectral averaged cross sections in a radial channel of the VR-1 reactor

The spectral averaged cross section is an important quantity used in a validation of nuclear cross section. When the cross sections are averaged over the neutron standard field (Cf-252(s,f) or U-235(n,f) neutron spectrum), they can be used for tuning of evaluations. This kind of quantities is very useful because the data in integral measurements can be determined with a significantly smaller uncertainties than the standard differential data. The experiment was aimed at the spectral average cross sections measurement and was performed in a radial channel of VR-1 reactor (with fuel enrichment 19.75 wt %). The results are in a good agreement within the uncertainties with a previous measurements in LR-0 reactor (with fuel enrichment 3.3 wt %), thus it supports the hypothesis that even significant amount of U-238(n,f) neutrons in the LR-0 reactor spectrum does not have a significant influence. The derived spectral averaged cross sections are as follows: 0.1709 +/- 0.0115 mb for Y-89(n,2n), 10.738 +/- 0.719 mb for Ti-46(n,p), 17.896 +/- 1.181 mb for Ti-47(n,p), 0.294 +/- 0.02 mb for Ti-48(n,p), 72.994 +/- 4.964 mb for Fe-54(n,p), 0.528 +/- 0.036 mb for Cu-63(n,a), 0.444 +/- 0.029 mb for Nb-93(n,2n)Nb-92* and 0.239 +/- 0.016 mb for Ni-58(n,x)Co-57.