In the event of a LOCA (loss-of-coolant accident) resulting from a hypothetical guillo-tine break in the suction line of the PLR (primary loop recirculation) pump for a BWR plant, the PLR pump will be reversely driven by the two-phase fluid flowing back at high speed in the line. For clarifying the two-phase flow characteristics of the PLR pump, which would be necessary for the analysis of pump behavior during LOCA, blowdown tests were conducted using three scale model pumps. The two-phase flow characteristics data for the pump were plotted with use of homologous curves method and the two-phase degradation multiplier in order to examine the effect of specific speed and void fraction. As a result of this study, it was shown that the characteristics of any pump with specific speed between Ns=500 and 4, 200 rpm?gpm1/2/ft3/4 can be obtained by interpolation. Experimental analyses were made using the TRAC code. Analytical results regarding pump inlet pressure, void fraction, volumetric flow rate and pump speed showed good agreement with the test results. This is a joint study of Japan BWR utilities and plant makers.
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