Exploration of Pressure Tube Ballooning Temperature

Abstract

During postulated event of large LOCA with Loss of ECI in CANDU reactors, the pressure tube may balloon to contact with its surrounding calandria tube to transfer heat to the moderator. The integrity of the fuel channel after the PT/CT contact was considered to be controlled by the moderator subcooling. To determine the required moderator subcooling to ensure fuel channel integrity after PT/CT contact, many experiments have been performed in the last three decades. In this work, the available PT/CT contact experiments data were collected and analyzed to determine the temperatures at which the pressure tube begins to balloon when different internal pressures are applied. The obtained data was correlated to internal pressure linearly. By assuming the pressure tube material and calandria tube material have similar mechanical properties, the obtained correlation may be applicable to calandria tubes in judging the integrity of the fuel channel when the calandria tube temperature is known.