Estimate of the Thermal Conductance Between Pressure Tube and Calandria Tube Upon Contact

Abstract

To confirm the integrity of the fuel channel after the contact with a given moderator subcooling in case of a large LOCA event, an analytical methodology has been developed to simulate the process of the pressure tube heatup, ballooning, contacting its surrounding calandria tube and the heat transfer to the moderator. Within this methodology, the pressure tube/calandria tube contact thermal conductance is a key parameter to the heat transfer process. In this work, the thermal contact conductance at 1MPa and 2MPa of the pressure tube pressure in case of film boiling heat transfer on the calandria tubes was estimated based on existing experiments. The estimated values were then applied in transient simulations for other tests to confirm its reasonableness.