Ex-Reactor Determination of Thermal Gap and Contact Conductance between Uranium Dioxide: Zircaloy-4 Interfaces. Stage I: Low Gas Pressure

摘要

A study of thermal gap and contact conductance between depleted uranium dioxide (UO2) and Zircaloy-4 (Zr4) has been made using two measurement apparatuses developed as part of this program. Both gap and contact conductance experiments were performed using the MPD (Modified Pulse Design) and MLD (Modified Longitudinal Design) techniques as a function of temperature, gas composition average mean-plane separation distances, contact pressure and surface morphology at atmospheric pressure: It was seen that H sub g is dependent on all these variables. A review of heat transfer formulations appropriate to estimation of gaseous conduction in the continuum and free molecular regime of gas dynamic is made. Comparison of MLD contact conductance (H sub C) results with those reported by the investigator Ross and Stoute, Dean, and Rapier is made. A review of models for predicting solid: solid thermal contact conductance based on surface roughness and elastic/plastic deformation of asperities and on surface waviness and elastic deformation is made.