OECD MCCI Project: Small-Scale Water Ingression and Crust Strength Tests (SSWICS). SSWICS-8 Test Data Report (Thermal Hydraulic Results)
- Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division
During the course of the first MCCI program, seven small-scale water ingression tests were performed with nominally 15 cm deep melt pools (up to 75 kg melt mass) made up of UO2 and varying amounts of either siliceous or limestone common sand concrete. The concrete contents varied from a low of 4 wt% to a high of 23 wt%. These tests demonstrated that melt cooling can be enhanced by water ingression and that the role of water ingression increases with decreasing concrete content. The dependence of the water ingression cooling rate on concrete content is strongest for melts containing less than 14% concrete. For melts with 14% or more concrete, little evidence of water ingression cooling was discernible. It was also found that the cooling rates of the three high concrete content melts (two at 14% and one at 23%) were similar to one another. One aim of this second MCCI program is to investigate the role of gas sparging on the corium cooling rate. The gases are a byproduct of the decomposition of concrete, which occurs when the material overheats. Gases generated near the corium/concrete interaction zone at the bottom of the melt are propelled up through the corium by buoyancy forces and the resultant gas flow has the potential to create melt porosity. This porosity is expected to supplement the fissures induced by thermal cracking. It is thought that these extra pathways will enhance the amount of water ingression cooling and quench the melt more rapidly than the case without sparging gases. This first test of the current program is a small-scale water ingression test with the same SSWICS apparatus that was used for the prior seven tests, but adapted to provide gas injection during quench to simulate the flow of concrete decomposition gases. The corium composition and operating conditions duplicate that of SSWICS-6, a fully oxidized PWR corium melt containing 15 wt% siliceous concrete quenched at a system pressure of 1 bar. The data provides an opportunity to compare the cooling rate and crust morphology of corium quenched with and without sparging gases. The test, conducted on January 25, 2007, is designated SSWICS-8 and this report includes a description of the test apparatus, the instrumentation used, plots of the recorded data, and some rudimentary data reduction to obtain an estimate of the heat flux from the corium to the overlying water pool. A subsequent report will address post test measurements of crust composition, permeability, and mechanical strength.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE; Nuclear Regulatory Commission (NRC); Organization for Economic Cooperation and Development (OECD) - Nuclear Energy Agency
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1177587
- Report Number(s):
- OECD/MCCI-2007-TR02; 114415
- Country of Publication:
- United States
- Language:
- English
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