OECD MCCI Project Small-Scale Water Ingression and Crust Strength Tests (SSWICS) SSWICS-10 Test Data Report (Thermal Hydraulic Results)
- Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division
The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core/concrete interaction (MCCI) when the reactants are flooded from above. These experiments provided unique, and for the most part repeatable, indications of heat transfer mechanisms that could provide long term debris cooling. However, the results did not demonstrate definitively that a melt would always be completely quenched. This was due at least partially to the fact that the crust anchored to the test section sidewalls in every test, which led to melt/crust separation, even at the largest test section lateral span of 1.2 m. This decoupling is not expected for a typical reactor cavity where the lateral span is much larger, ~5-6 m. Instead, the crust is expected to fracture under the weight of the coolant and the crust itself so that coolant contact with the melt is maintained. However, because of a lack of knowledge of the strength of the crust, one cannot be certain that it would actually fracture under such circumstances. As part of the MCCI-1 and MCCI-2 programs, a series of separate-effects experiments has been conducted to measure corium quench rates and crust strength to investigate the various debris cooling mechanisms identified in the MACE program. Each quench test involved cooling a molten mass of UO2, ZrO2, and concrete constituents, which produced a corium ingot that was later load tested to determine its mechanical strength. The quench tests were designed to optimize measurements of heat flux from the corium surface and consequently the ingots that were formed were not of optimal thickness for the strength measurements. For the quench tests, a minimum corium depth of 150 mm was deemed necessary to obtain a satisfactory heat flux measurement. However, 150 mm is too much for optimal load testing and so the ingots were sectioned (cut in the radial direction) to increase their aspect ratio (diameter/thickness) to make them more suitable for load testing. Unfortunately, the cutting process is laborious and involves much handling of the ingot and therefore decreases the certainty that the mechanical strength of the sections is close to that of the original ingot. This uncertainty would be eliminated if the ingots produced by the quench tests could be tested without having to cut them. SSWICS-9 & 10, in contrast to previous tests, are designed to optimize the ingot for load testing. A reduced amount of corium will be used in the quench test to produce a thinner ingot. The ingot will then be load tested without sectioning. This report details the results of the SSWICS-10 quench test.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission (NRC), Rockville, MD (United States)
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1177583
- Report Number(s):
- OECD/MCCI-2008-TR02; 114410
- Country of Publication:
- United States
- Language:
- English
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