Performance of a LOFT drag-disc turbine transducer and gamma densitometer under transient two-phase blowdown conditions

One of the basic parameters measured during the LOFT loss-of-coolant experiment (LOCE) is two-phase mass flow rate. The flow measurement transducers used in LOFT were designed to determine the mass flow rates at discrete points in a transient two-phase flow field (free field measurement configuration). These instruments are calibrated in steady state single-phase water (full flow configuration). The single phase calibrations are used with two-phase flow measurement models to compute two-phase mass flow. The paper reports a performance evaluation of LOFT two-phase flow measurement techniques under transient two-phase flow conditions