• Nuclear Engineering and Technology
• /
• v.36 no.6
• /
• pp.571-581
• /
• 2004

A methodology is proposed for the evaluation of a steam explosion load on a reactor scale by evaluating the steam explosion model against the experimental data. Being part of the OECD/SERENA program,, appropriate data was selected by international experts and the analytical model of TEXAS-V was chosen. The procedure consists of two steps. the pre-mixing model was verified against the FARO L-14 and FARO L-28 data. The explosion model was verified against the experimental data of KROTOS-44, FARO L-33, TROI-13, and TROI-34. The capabilities and deficiencies of the fundamental models of the TEXAS-V are reviewed in terms of their adequacy in a simulation of steam explosion on a reactor scale.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.12
• /
• pp.1051-1060
• /
• 2010

The effect of materials on fuel coolant interactions (FCIs) was analyzed on the basis of a solidified particle size response for TROI experiments.$^{(1)}$ The solidified particle size response can provide an understanding of the relationship among the initial condition, the mixing, and an explosion. Through a comparison of the size distributions of the solidified particles in the case of explosive and non-explosive FCIs, it is revealed that an explosive FCI results in the production of a large amount of fine particles and a small amount of large particles. The material effect of the size of solidified particles was analyzed using non-explosive FCIs without losing the information on the mixing. This analysis indicates that an explosive melt includes large particles that participate in the steam explosion, whereas a nonexplosive melt includes smaller particles and finer particles.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.414-419
• /
• 2003

In the recent TROI experiments, melts of zirconia and two different compositions of corium were used to observe the occurrence of a steam explosion when it came into contact with water at two different depths. The compositions of the corium were 70 : 30 and 80 : 20 in weight percent of $UO_{2}$ and $ZrO_{2}$, and the mass of the corium was about 10kg. The depth of water in the interaction vessel was 67cm and 130cm. A steam explosion did not occur in the interaction between 80 : 20 corium melt and water at 130cm depth, while steam spikes were observed in the interactions between corium melts of two different compositions and water at 67cm depth. A strong steam explosion occurred in the interaction between 5.43kg of zirconia melt and water at 67cm depth. This fact shows that the explosivity of zirconia is much greater than that of corium.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.2041-2046
• /
• 2004

Recently series of steam explosion experiments have been performed in the TROI facility to identify the influence of corium compositions on the occurrence of a spontaneous steam explosion varying corium melt composition. The compositions of the corium were 0 : 100, 50 : 50, 70 : 30, 80 : 20 and 87 : 13 at weight percent of $UO_2$ to $ZrO_2$, and the mass of the corium was about 10kg. Corium melt at 0 : 100 weight percent (pure zirconia) caused a strong spontaneous steam explosion, and melt at 70 : 30 weight percent(eutectic corium) led to a weak steam spike, while melts at other compositions did not result in spontaneous steam explosions, when they came into contact with 67cm deep water pool at room temperature. It seems that the explosivity of pure zirconia is stronger than that of corium at other compositions and a steam explosion is not likely to occur with corium melts at non-eutectic compositions which are included in mushy zone region.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.3027-3032
• /
• 2007

To understand the complex phenomena performed in steam explosion, the fast and global measurement of the steam distribution is imperative for this extremely rapid transient stimulation of the bubble breakup and coalescence due to turbulent eddies and shock waves. TROI, the experimental facility requests more robust sensor system to meet this requirement. In Europe, researchers are prefer a X-ray method but this method is very expensive and has limited measurement range. There is an alternative technology such as ECT. Because of TROI's geometry, however, we need axial tomography method. This paper reviews image reconstruction algorethms for axial tomography, including Tikhonov regularization and iterative Tikhonov regularization. Axial tomography method is examined by simulation and experiment for typical permittivity distributions. Future works in axial tomography technology is discussed.

• Proceedings of the Korean Nuclear Society Conference
• /
• 2004.10a
• /
• pp.457-458
• /
• 2004

• Proceedings of the Korean Nuclear Society Conference
• /
• 2004.10a
• /
• pp.261-262
• /
• 2004

• Proceedings of the KSME Conference
• /
• 2001.06e
• /
• pp.57-62
• /
• 2001

Korea Atomic Energy Research Institute (KAERI) launched an intermediate scale steam explosion experiment named Test for Real cOrium Interaction with water (TROI) using reactor material to investigate whether the corium would lead to energetic steam explosion when interacted with cold water at low pressure. The melt-water interaction is confined in a pressure vessel with the multi-dimensional fuel and water pool geometry. The cold crucible technology, where the mixture of powder in a water-cooled cage is heated by high frequency induction, is employed. In this paper, results of the first series of tests ($TROI-1{\sim}5$) were discussed. The ZrO2 jets with 5kg mass and 5cm diameter were poured into the 67cm deep water pool at $30{\sim}95^{\circ}C$. Either spontaneous steam explosions or quenching was observed. The morphology of debris and pressure wave profiles clearly indicates the each case.

• Proceedings of the KSME Conference
• /
• 2002.08a
• /
• pp.397-400
• /
• 2002

Vapor explosion is one of the most important problems encountered in severe accident management of nuclear power plants. In spite of many efforts, a lot of questions still remain. So, KAERI launched a real experimental program called TROI using $UO_{2}$ and $ZrO_{2}$ to investigate the vapor explosion. Besides TROI tests, a small-scale experiment with molten-tin/water system was performed to quantify the characteristics of vapor explosion and to understand the phenomenology of vapor explosion. A vapor explosion was observed while the amount of air bubble and water temperature were systematically varied The mass and temperature of tin are $50\;g\;and\;150^{\circ}C$, respectively. Water temperature is set to $24^{\circ}C\;and\;50^{\circ}C$. The void fraction of air bubble ranges from $0\;to\;10\;{\%}$. The strength of vapor explosion was measured using dynamic pressure sensors attached in reactor tube wall. as a function of void fraction. In addition, a high speed video filming up to 1,000 flame/sec was taken in order to visually investigate the behavior of the vapor explosion .

• Proceedings of the Korean Nuclear Society Conference
• /
• 2005.05a
• /
• pp.609-610
• /
• 2005