Analysis of Exposure Dose Rate and Neutron Flux
Density Dynamics in the Shelter Object
of the Chornobyl NPP

M. V. Saveliev, O. V. Mykhailov, D. O. Sushchenko

Institute for Safety Problems of Nuclear Power Plants,
NAS of Ukraine, 36a, Kirova st., Chornobyl, 07270, Ukraine



Application software was developed for automating the algorithms of mathematical data processing of the nuclear safety monitoring system of the integrated automated monitoring system (NSMS IAMS) of the New Safe Confinement — Shelter Object complex (NSC-SO) at the Chornobyl NPP. The developed software was tested and deployed on computing equipment at the Institute for Safety Problems of Nuclear Power Plants. The machine analysis of the NSMS’s data was carried out and results were obtained in form of general trends in the dynamics of the neutron flux density (NFD) and the γ-radiation exposure dose rate (EDR) and another graphical and tabular format. The machine analysis was performed both on the data before and after installing the Arch of NSC into the design position over the Shelter Object. Conclusions were made regarding the possibility of applying the developed tool for automating routine procedures for the analysis of multiple arrays of measurement data to obtain information necessary for assessing the state of nuclear hazardous clusters located in the NSC-SO. In addition to the standard forms of reporting materials in the form of graphs and tables, a matrix form of presenting the results of the correlation-regression analysis is proposed, which allows you to visually assess the degree of interrelationships between the values of the control parameters simultaneously in all measuring channels of the NSMS IAMS. The results of the forecast of the NFD and EDR dynamics using the established regression functions were verified by comparing the calculation and measurement data as of January 1, 2022. A conclusion was made regarding the degree of reliability of forecasting the values of the NFD and EDR in the NSC-SO using the developed software.

Keywords: Chornobyl NPP, New Safe Confinement, Shelter object, application software, neutron flux density, exposure dose rate, regression analysis.


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