The effect of subchannel thermohydraukic in nuclear reacior cores

The purpose of the present investigation is to validate the subchannel theoretical analysis approach for predicting adetailed local mass and enthalpy distributions in LWR fuelbundles, both for normal operational conditions as well for accidental situations.Experimental tests were performed to investigate enthalpy and mass flow distribution at the outlet of 16- rodcluster test section with PWR and BWR geometry.Test section was heated by uniform heating, axially and dially,under steady state condition.Sampling of 5 from 6 characteristic subchannels was performed using isokinetic technique andanalysis the outlet samples by a calorimetric method.The testsection were provided with typical geometrical configurationsfor PWRs and BWRsThe subchannel measurements have been carried out with160 bars Cfor PWR geometry ) and 70 bars Cfor BWR geometry )working pressure , 70 to 105 w/cm (PWR) and10 to 75 w/cmCBWR) of heat flux density 2000 to 3500 kg/m.sec (PWR) and1000 to 2000 kg/m.sec CBWR) mass flux and -20 to 20% CPWR)and 0 to 30% CBWR) average bundle outlet quality In this range,the experimsntal tests wsre generated and ’ charecterized by simultaneous flow and enthalpy monitored subchannels.measurements in five