OECD/NEA ROSA Project experiment on steam condensation in PWR horizontal legs during large-break LOCA

PWR大破断LOCA時の水平配管での蒸気凝縮に関するOECD/NEA ROSAプロジェクト実験

竹田 武司 ; 大津 巌 ; 中村 秀夫  

Takeda, Takeshi; Otsu, Iwao; Nakamura, Hideo

Separate-effect experiment simulating steam condensation on emergency core cooling system (ECCS) water in PWR cold legs during reflood phase of large-break loss-of-coolant accident (LBLOCA) was conducted in OECD/NEA ROSA project using the Large Scale Test Facility (LSTF). The boundary test conditions were defined based on PWR LBLOCA analysis by RELAP5/MOD3.2.1.2 code considering typical Japanese safety analysis conditions. Significant condensation of steam appeared in a short distance from the simulated ECCS injection point, and the steam temperature in the test section decreased immediately after the initiation of the ECCS water injection. Fluid temperature distribution at 50 mm downstream from the ECCS injection point was significantly non-uniform, but became almost uniform in less than 350 mm. Clear images of high-speed video camera were obtained on droplet behaviors through the viewer at 200 mm downstream from the ECCS injection point, especially for annular mist flow.