Measurement of neutron leakage from 238U,232Th,Be and Pb spherical shells with 14 MeV neutron central sources

The accuracy of forecasting project parameters of thermonuclear ractor (TNR) blanket depends on the authenticity of constants used in calculations. A good check-up of authenticity is provided by comparison of calculation results with results of integral experiments. The method of measuring neutron escapes from spherical assemblies (the method of boron tank) is briefly described. The results of measuring neutron escapes from spherical shells of different thickness from 238U, 232Th, Be and Pb with normalization for one neutron of 14 MeV sourse are presented. The comparison of experimental data with calculations according to BLANK program using constants from ENDL and UKNDL libraries has shown that the value of neutron escapes from Pb-spheres is 5.5% higher than calculated values. For Th-spheres experimental results are higher than those calculated and with the shell thickness of 10 cm the difference is 11%. Neutron escapes from U- and Be-spheres are produced in a satisfactory way in the blank program