The Influence of Variations in the Water Depth and Melt Composition on a Spontaneous Steam Explosion in the TROI Experiments

Conference · Thu Jul 01 04:00:00 EDT 2004

OSTI ID:21160555

Kim, J H; Park, I K; Min, B T; Hong, S W; Shin, Y S; Song, J H; Kim, H D ^[1]

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1. Thermal-hydraulics and Safety Research Team, Korea Atomic Energy Research Institute, 150 Dukjin-Dong, Yusong, Taejon 305-353 (Korea, Republic of)

In the recent TROI test series, six steam explosion experiments were performed using Zirconia (ZrO{sub 2}) melt and corium melts of two different compositions interacting with water pools of various depths at room temperature and atmospheric pressure. These experiments were aimed at finding the effect of the water depth and melt composition on the occurrence of a spontaneous steam explosion. The compositions (UO{sub 2}: ZrO{sub 2}) of the corium were 80: 20 and 70: 30 at a weight percent and the mass of the corium interacting with the water was about 10 kg. The water depth was varied from 67 cm to 130 cm in these experiments. In the case of the three interactions between the 80: 20 corium melt and the water pool of 130 cm in depth, no spontaneous steam explosion occurred. Meanwhile, from the two interactions between the corium melts of two different compositions (80: 20 and 70: 30 at weight percent) and a 67 cm deep water pool, steam spikes were believed to have been observed. Also, from one interaction between the zirconia melt ({approx}5.43 kg) and a 67 cm deep water pool, an explosive steam explosion occurred which was accompanied with strong pressure waves of 5.5 MPa and a dynamic load greater than 500 kN. It is thought that the probability of a self-triggering of a steam explosion is reduced in a deep water pool since the melt could be cooled down and then solidified due to its long journey through the water pool before a contact between the melt and the vessel bottom beneath the water, which is supposed to be the time for the triggering of a steam explosion. By changing the composition of the melt to pure zirconia, the triggerabilty and explosiveness of the zirconia melt was found to be much higher than that of the corium. In the case of a steam explosion, the pressure vessel was heated up less than that in the no steam explosion cases. This probably results from the fact that the pressure vessel heat-up was lowered by the dispersion of the water sent to the atmosphere by a steam explosion, while it was increased by the continuous generation of hot steam in the no steam explosion cases. (authors)

• Research Organization: American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
• OSTI ID: 21160555
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CORIUM
DEPTH
EXPLOSIONS
MAXIMUM PERMISSIBLE ACTIVITY
PRESSURE VESSELS
STEAM
URANIUM DIOXIDE
WATER
ZIRCONIUM OXIDES