OECD MCCI Project: Small-Scale Water Ingression and Crust Strength Tests (SSWICS) SSWICS-11 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 (MCCI-1), seven small-scale water ingression tests were performed with 75 kg corium melts 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 made possible by thermal stress-induced cracking, 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 melts with siliceous concrete cooled at about the same rate as melts with a similar amount of limestone common sand concrete. One aim of the current MCCI program (MCCI-2) 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 stress cracking. It is thought that these extra pathways could enhance the amount of water ingression cooling and quench the melt more rapidly than the case without sparging gases. The first test of the MCCI-2 program was SSWICS-8, a melt quench experiment that duplicated the conditions of SSWICS-6 while adding gas sparging to simulate the flow of concrete decomposition gases. The melts for these tests were formulated to simulate a fully oxidized PWR corium melt containing 15 wt% siliceous concrete. They were both quenched at a system pressure of 1 bar. The new data was to be used to make a comparison between the cooling rates and crust morphologies of corium quenched with and without sparging gases. SSWICS-8 was an operational success in every respect except for the fact that the injected gas appeared to bypass the melt by escaping through the basemat/liner joint and/or flowing up around the melt between the melt/liner interface. Post test examinations of the ingot and a review of the data determined that SSWICS-8 was effectively a repeat of SSWICS-6, i.e., a melt quenched in the absence of sparging gases. SSWICS-11, the subject of this report, is a repeat of SSWICS-8 with a modified sparging system designed with the goal of ensuring that the injected gas does not bypass the melt. The test was conducted on November 5, 2008. 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.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE; Organization for Economic Cooperation and Development (OECD) - Nuclear Energy Agency; Nuclear Regulatory Commission (NRC)
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1177574
- Report Number(s):
- OECD/MCCI-2009-TR01; 114324
- Country of Publication:
- United States
- Language:
- English
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OECD MCCI Project: Small-Scale Water Ingression and Crust Strength Tests (SSWICS). SSWICS-8 Test Data Report (Thermal Hydraulic Results)
OECD MMCI Small-Scale Water Ingression and Crust Strength tests (SSWICS) SSWICS-1 final data report, Rev. 1 February 10, 2003.; Report, Rev. 1