Steam-water mixing and system hydrodynamics program. Task 4. Quarterly progress report, April 1, 1977--June 30, 1977. [PWR]

Experimental studies were conducted in a 2/15-scale model of a four-loop pressurized water reactor at pressures to 75 psia to extend the understanding of steam-water interaction phenomena and processes associated with a loss-of-coolant accident. The initial test series in this facility was completed which consisted of quasi-steady penetration tests. Additionally, plenum filling studies with and without hot walls and no cold leg steam were completed. Preliminary analyses of these data indicate that results obtained from both modes of testing, quasi-steady penetration with lower plenum draining and plenum filling, provide similar results which can be used to develop downcomer penetration correlations and to compare results from tests conducted in either operational mode. Comparisons of 1/15- and 2/15-scale data show that fluid behavior in both sizes is similar in that the observed effects on downcomer penetration of core steam flow, system pressure, ECC flow, and ECC water subcooling are common to both systems. The 1/15 and 2/15 data are compared using the j* or flooding parameters as the scaling basis. Although the comparisons appear to show good agreement, analyses indicate that a statistically significant difference exists in the data. This difference is being examined further. Two different forms are examined for correlatingmore » the combined sets of 2/15- and 1/15-scale data. Statistical tests were used to select the most appropriate form. Comparisons of data and correlational outputs are presented for both sized systems to illustrate the degree of data representation.« less