Measurement of spatial distributions of the threshold detector activation integrals for the model of a thermonuclear reactor with a molten salt blanket in the 1-14 MeV neutron energy range

Results of measuring the spatial distribution of threshold detector activation integrals in the model of a thermonuclear reactor (TNR) blanket based on the melt of fluorine salts are presented. The investigated model of the TNR blanket constitutes a sphere, 400 mm in diameter, uniformly filled with melt of fluorine salts of lithium and beryllium (LiF, BeF2) in the relation of 50-50 mol.%. As a neutron source the NGI-200 neutron generator was used. Thirteen types of detectors covering the 1-14 MeV neutron energy range have been used during the measurements. A comparison is made of obtained experimental results with calculations performed in accordance with the BLANK program. The experiments showed that the chosen set of activation detectors is not optimum and needs furhter perfection. Specifically, the further use of 197Au(n,2n)196Au and 27Al(n,p)27Mg reactions in inexpedient. It is proposed to replace the latter reaction by the 204Pb(n,n')sup(204m)Pb. The analysis of obtained results shows that the calculations agree well with the experiments in the 1-8 MeV energy range. For reactions whose energy threshold esceeds 8 MeV the calculated and experimental discrepancies are greater