Demonstration Of Instrument Periodic Test Frequency In The Nuclear Power Plant's Refueling Cycle Extension

The project of nuclear power plant's refueling cycle extension is the unit prolonging the overhaul cycle from 1year to 1.5 years under the condition of security technology.The nuclear power plant need to original refueling cycle in the system equipment regularly test,maintenance cycle adaptive changes of the fuel cycle extended,demonstrating and analysing the influence of cycle extended,the demonstration of instrument periodic test cycle is the key way to extend the unit overhaul period.The more effective method of Instrument periodic test cycle demonstration is experience feedback method,demonstrate the performance reliability of instrument after extended the unit overhaul period base on the analysis of history instrument periodic test data,The nuclear power plants have ten thousands of historical data,the effectively method will improve the reliability of the whole demonstration results.In this paper deeply studyed the method base on the basis of existing research for the demonstration of instrument periodic test cycle,mainly including the following aspects:(1)Studyed the scheme of how to demonstrate instrument periodic test frequency.proposed an effective project selection and classification scheme,screened the necessary instrument periodic test cycle project and classified the project according to their different function,Design appropriate scheme of data collection and cycle adjustment.(2)Studyed the method of demonstrating instrument calibration cycle.discussed the As-Found and As-Left(AFAL)methodology,proposed an improved AFAL analysis by improving the identifying abnormal point and analysis the data distribution features of traditional methodology,to demonstrate the feasibility of extending the instrument calibration cycle.In the view of the insufficient calibration data project,through the calculation of the uncertainty evaluation of instrument performance parameters of the instrument's reliability(3)Studyed the method of demonstrating instrument validation test cycle.Established an weibull reliability model,analysed the ability of instrument system's failure prevention to demonstrate the easibility of extending instrument validation test cycle.This paper Listed instrument periodic test cycle demonstration examples to verify the proposed method's effective and correte.The example of demonstrating the Chemical and Volume Control System pressure instrument calibration cycle shows,Improve AFAL analysis method can make up for the traditional method in identifying abnormalpoint application range is small and can't accurate analysis data's normal distribution characteristics,It also could effectively analyze the drift trend of instrument.The example of demonstrating the Feedwater Flow Control System level transmitter validation test cycle shows,The instrument weibull distribution model can accurately calculate the instrument failure life and failure time.