Measurement of thermal gap conductance using the laser flash method
- Department of Mechanical and Aerospace, Utah State University, Logan, UT 84322 (United States)
- Idaho National Laboratory, Idaho Falls, ID 83415 (France)
Thermal gap conductance refers to overall heat conductance through a gas-filled gap as interface thermal resistance between the gas and surface has to be considered. The analysis of new ATR (Advanced Test Reactor) fuel experiments requires experimental data and models for the gap conductance of the cladding/fuel capsule gap, which typically varies from 5 μm to 50 μm and is filled with He at 1-3 atm. Although past research has studied the gap conductance between UO{sub 2} fuel and Zircaloy cladding, new experiments are needed to provide the gap conductance data between HT9 and stainless steel 316, and between advanced fuels and advanced cladding in the Accident Tolerant Fuels program. In this paper, the laser flash method is modified to measure the gap conductance. The gap is formed by welding two stainless steel 316 disks with three spacers. The temperature at the rear surface, after exposure to the laser pulse at the front surface, is modeled with 1D heat transfer through three layers. The analytic solution is then fitted with the measured temperature to determine gap conductance. The sensitivity analysis based on the 1D assumption and 3D numerical simulations were performed to assess the sensitivity and uncertainty of the measurement. It is concluded the heat capacity of the gas in the gap has minimal impact on the measurement, which indicates that the thermal property determined by this method is the thermal conductance, instead of the thermal diffusivity. Convective heat loss through sidewalls under the current experimental design has insignificant influences. Heat transfer through spacers may cause up to 10% overestimation of thermal gap conductance, but the effects can be mostly eliminated by the design of grooves on samples. The result established a pathway for gap conductance determination. (authors)
- Research Organization:
- American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
- OSTI ID:
- 22750130
- Resource Relation:
- Conference: Top Fuel 2016: LWR fuels with enhanced safety and performance, Boise, ID (United States), 11-15 Sep 2016; Other Information: Country of input: France; 21 refs.; Related Information: In: Top Fuel 2016 Proceedings| 1670 p.
- Country of Publication:
- United States
- Language:
- English
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