MDRAP - A MATLAB-Based Detector Response Analysis Package

Abstract

An analysis program has been developed, in the MATLAB environment, for determining in-core flux detector dynamic response characteristics from a combined knowledge of the local detector flux and measured detector output. Critical to the program is an accurate estimate of the local detector flux. The estimated local detector flux is input to a detailed model of the detector and its electronic compensators; the model output is compared with the recorded signal. The model of the detector is then iteratively adjusted to minimize the mean square error between the output of the model and the recorded signal. The process is completely automated, requiring no manual input by the code user. The program has been used on both Pt-clad and vanadium detectors for the Point Lepreau Nuclear Generating Station for various power rundown tests. This paper describes the code and presents results from the analysis of Pt-clad detectors with data from the 1997 shutdown system (SDSl) Trip Test at Pt. Lepreau. 1. Introduction The dynamic response of i n-core flux detectors (ICFDs) is characterized by an immediate or prompt response and a delayed response. The delayed response is assumed to be linear and can be adequately represented by a sum of first-order lags, each characterized by an amplitude and a time-constant. The amplitude is the fraction of the total steady-state response at equilibrium resulting from the particular lag. The time-constant determines the rate of change of the delayed component. The total delayed response is the sum of the amplitudes of all the lags. Since the total fractional response is unity, the prompt fraction is one minus the delayed fraction. In the analysis of the 1995 shutdown system 1 (SDS 1) Trip Test at Point Lepreau, discrepancies were noticed between the Reactor Fueling Simulation Program (RFSP) [I] simulated detector readings and measured values for SDS 1 and Reactor Regulating System (RRS) detectors. The detectors for both systems are straight individually