Determination of Mass Flow Rates from Measured In-Core Two-Phase Flow Transit Times in a Boiling Water Reactor

Abstract

By analysing the neutron noise signals of the in-core detectors, the two-phase flow transit times have been measured for unit 1 of Tarapur Atomic Power Station (General Electric Boiling Water Reactor). Our study has shown that it is reasonable to identify the fluid velocity derived from the measured transit time with the volumetric flux. This interpretation offers the advantage of determining the mass flow rate by using the measured transit time and the steam quality obtained by the heat balance. Further, it is feasible to infer gross flow rate changes by combining the calculated value of the transit time as a function of flow with the periodic measurements of transit time over the operating cycle of the reactor.