Unfolding of initial distributions of neutron activities using results of measurements of irradiated reactor fuel assemblies

Analytical solution of problem of unfolding of linear space distribution of sources of own neutron radiation in spent fuel assemblies of power-generating reactors (RBMK-1000) is considered in the report. Continuous and discrete modes of scan are analyzed. The problem is solved for piecewise continuous function of activity distribution with finite number of brakes. An absence of exact information on space boundaries of measured object is supposed, that corresponds to the real measurement conditions in a fuel assembly storage pond. A method of determination (calculation) of boundary points of measured object is suggested. Justification of obtaining of unbiased estimate of integral neutron counting rate in a case of the continuous scan is given. Main mathematical procedures of problem solution are justified and the continuous scan calculation formulas for regularized solution are presented. Model solutions of problem of restoration of initial experimental data and also the experimental data unfolding of neutron measurements of the RBMK-1000 spent fuel assemblies are considered. The results obtained may be used for solution of wide range of problems related to neutron source measurements