About the Requirements and Recommendations of the Regulatory Body to Error Estimation of Neutronics Calculations

Abstract

The article discusses the issues of determining the error of neutron-physical calculation taking into account its specificity, the features of the code implementation of various calculation methods and the requirements of regulatory documents in the field of atomic energy. According to the requirements of Russian regulatory documents, the design and safety analysis of nuclear facilities must be carried out on the basis of a conservative approach. A conservative approach is an approach to design and building of nuclear power plants (NPP), when by choosing values of parameters and characteristics of NPPs, NPP sites and (or) other methods, more unfavorable results are obtained during accident analyze of NPP. In order to implement the principle of conservatism in neutron-physical calculations, in addition to determining the desired quantity, it is necessary to determine the error in the calculation of this quantity. The safety of nuclear facilities is mainly analyzed through calculations using codes. Russian regulatory documents require codes to be verified and validated, the result of verification and validation is the certification passport of the code, which contains the errors calculated by the code values. They are established as a result of verification (validation) of the code. It is noted that it is necessary to take into account measurement errors in experiments, including those carried out at operating power units, for code verification. It is noted that in the Safety Guide RB-061-11, concerning the neutron-physical calculation, recommendations are given to determine the error, the article presents their analysis and synthesis.