USEFULNESS OF REACTOR NOISE ANALYSIS,THE UTILITY PERSPECTIVE

摘要

Two different measurement techniques have been used in the CANDU nuclearrngeneration stations of Ontario Power Generation and Bruce Power to test the dynamics ofrnsafety related systems and instrumentation. The first technique, called reactor noisernanalysis, utilizes the small fluctuations (noise) of detector signals measured at steadystaternfull-power operation. Instrumentation signals included in the reactor noisernmeasurements are in-core flux detectors (ICFDs), ion chambers, flow, pressure, and levelrntransmitters, and resistance temperature detectors (RTDs). Their frequency dependentrnnoise signatures are regularly measured during steady-state operation, and are used forrnanomaly detection and parameter estimation (in-situ response time estimation).rnThe second technique is based on detector signals measured during an operatorinitiatedrnreactor trip at the beginning of scheduled outages. Measurements of ICFD andrnion chamber signals responding to the insertion of shut-off rods (Shutdown System No.1,rnSDS1 trip), or to the injection of neutron absorbing poison (Shutdown System No.2,rnSDS2 trip) are regularly carried out at all stations. The purpose of the trip responsernmeasurement is (1) to estimate the effective prompt fractions of the shutdown systemrnICFDs, relative to the trip response of the ex-core ion chambers (100% prompt referencernsignals), (2) to assess the effectiveness of the trip mechanism (poison injection, orrninsertion of shut-off rods) by measuring the timing of signal changes of ICFDs and ionrnchambers as a function of detector location, and (3) to provide trip measurement data forrnvalidating safety analysis models and assumptions on response times.