Hot Wire Needle Probe for In-Pile Thermal Conductivity Detection

Conference · Thu Nov 01 04:00:00 EST 2001

OSTI ID:1004270

Daw, Joshua; Rempe, Joy; Condie, Keith; Knudson, Darrell; Wilkins, S Curtis; Fox, Brandon S; Ban, Heng

Thermal conductivity is a key property of interest for both nuclear fuel and structural materials, and must be known for proper design, test, and application of new fuels and structural materials in nuclear reactors. Thermal conductivity is highly dependent on the physical structure, chemical composition, and the state of the material. Typically, thermal conductivity changes that occur during irradiation are measured out-of-pile by Post Irradiated Examination (PIE) using a “cook and look” approach in hot-cells. Repeatedly removing samples from a test reactor to make out-of-pile measurements is expensive, has the potential to disturb phenomena of interest, and only provides understanding of the sample's end state at the time each measurement is made. There are also limited thermophysical property data for advanced fuels. Such data are needed for simulation design codes, the development of next generation reactors, and advanced fuels for existing nuclear plants. Being able to quickly characterize fuel thermal conductivity during irradiation can improve the fidelity of data, reduce costs of post-irradiation examinations, increase understanding of how fuels behave under irradiation, and confirm or improve existing thermal conductivity measurement techniques. This paper discusses advancements from Idaho National Laboratory (INL) / Utah State University (USU) examinations, including background information, governing equations, experimental setup, detailed results, and conclusions for both a steady state and a transient method. Experimental findings of the INL/USU steady state method examinations help to better understand limitations and benefits of two-thermocouple methods, where laboratory results can be extrapolated to in-pile applications. Additionally, results from the transient method offer the immediate potential for in-pile application, as the method reduces the impact on the sample from only a small centerline sensor, measurement times (e.g., only minutes for complete transient tests compared to hours or days for steady state tests), and uncertainties from estimating difficult parameters such as, in-pile fuel to cladding contact resistance needed for two-thermocouple approaches.

• Research Organization: Idaho National Laboratory (INL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 1004270
• Report Number(s): INL/CON-10-19633
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
BUILDING MATERIALS
CHEMICAL COMPOSITION
DESIGN
DETECTION
HOT CELLS
IRRADIATION
In-Pile Instrumentation
NUCLEAR FUELS
Nuclear Fuel Properties
POST-IRRADIATION EXAMINATION
PROBES
REACTORS
SIMULATION
TEST REACTORS
THERMAL CONDUCTIVITY
TRANSIENTS
Thermal Conductivity Measurement