Investigation of dependence of BN-600 reactor sector fuel cladding leak detection system responses on the operation parameters

The purpose of the present study was to investigate the dependence of readings of the sector fuel cladding leak detection system (SFCLDS) of the BN-600 nuclear power reactor on the operational parameters and the development of regression model for forecasting the SFCLDS background parameters.List of parameters of regression model for determination of the background level for the SFCLDS measurement channel was developed. Calculated value of temperature outside the detection unit (DU) which is proportional to the value of temperature increment in the DU was included in the composition of the model along with parameters of reactor power level, temperature in the DU and time from the start of time interval between reactor refueling operations.Coefficients of the regression model were determined using the least squares method (LSM) with application of stepwise regression with sequential addition of parameters to the model. The criterion for inclusion of the parameter in the composition of the model was the reduction of the value of average error of approximation e and normalization of distribution of model residues. Data processing was performed using MS Excel, MS Access and VBA.Results of construction of the model demonstrated that all parameters are statistically significant. Uncertainty of the developed model for forecasting the SFCLDS background parameters for all sections of the data for one BN-600 cycle between refueling operations does not exceed 1% which satisfies the original requirements.Implemented studies of dependence of background on the reactor operational parameters are of practical importance and are original scientifically - similar types of research have not been done previously. Upon completion of testing and validation of the developed model using extended volume of reactor operation data the issue will be addressed of the implementation of the methodology within the composition of the SFCLDS of BN-600 and BN-800 reactors.