Mixing of emergency core cooling water with steam: 1/3-scale test and summary. Final report

The Westinghouse steam/water mixing program was initiated to obtain test data and to develop thermal/hydraulic models which will represent the steam/water interactions expected in a PWR cold leg during a postulated Loss-Of-Coolant Accident (LOCA). The Westinghouse program comprises two major test series: 1/14-scale (2-inch-diameter simulated cold leg) tests and 1/3-scale (10.4-inch-diameter) tests. The 1/14-scale series has been reported in Reference 1. This describes the 1/3-scale steam/water mixing tests and data. Comparisons of these data are made with the Combustion Engineering 1/5- and 1/3-scale test data as well as the previously obtained 1/14-scale Westinghouse data. The 1/3-scale tests covered the range of parameters addressed in the 1/14-scale tests, excepting blow down, and the test parameter range was expanded to include post-reflood conditions. The primary information desired from the reflood tests was the pressure drop which occurred across the steam/water mixing zone, whereas for the post-reflood tests the primary interest was in the degree of mixing which occurred in the simulated cold leg as indicated by the effluent temperatures