Method of Performing Uncertainty Analysis Using Neutron Covariance Data for HTGR

The aim of this work is to develop methods for calculating the neutronic parameters of HTGR and to perform uncertainty analysis with the aid of design programs and neutron covariance data. The method and software modules for preparing multigroup libraries of covariance data for individual isotopes based on a 44-group library of covariance data of the SCALE-6 computational complex were improved in the course of this work. Correction factors are introduced to improve the accuracy of the method. The WIMSD-5 code with a 69-group cross-section libraries, created on the basis of ENDF/BVII.0 and ENDF/BVII.1 evaluated nuclear data files, is used for the neutronic calculations. Calculations of the uncertainties of one-group fission and absorption cross sections for the main isotopes of the elements of the MHTGR-350 core as well as the neutron multiplication coefficients for the fuel-compact cells and fuel-block cells of the MHTGR-350 reactor were performed to verify the developed method.