Prediction of pressure tube integrity for a large LOCA in CANDU
The core of a Canada deuterium uranium (CANDU) reactor consists of a large number of horizontal pressure tube fuel channels connected by individual feeder pipes to common horizontal headers above the core. Each pressure tube contains 37-element fuel bundles and is enclosed by a concentric calandria tube. The annular gap between the pressure tube and the calandria tube is filled with gas. The calandria tubes are surrounded by a heavy-water moderator. The pressure tubes provide a pressure boundary between the high-pressure primary heat transport system and the low-pressure, relatively cold moderator system. In a number of postulated accident scenarios, some of the fuel channels at decay power levels are predicted to experience periods of low flow. In such a period, the coolant boils and stratifies, exposing the upper fuel elements and the upper part of the pressure tube to superheated steam. The exposed fuel elements and the surrounding pressure tube then heat up. At sufficiently high tube temperature and channel pressure, the pressure tube may strain radially into contact with the relatively cold calandria tube, transferring its stored heat to the moderator. Stratified channel coolant conditions and falling channel water level, however, may cause temperature gradients to develop around the pressure tube circumference from peak temperatures at the top of the tube to the saturation temperature at water level. To predict the temperature distribution around the pressure tube circumference under stratified channel coolant conditions, a model named AMPTRACT was developed.
- OSTI ID:
- 7118607
- Report Number(s):
- CONF-8711195-
- Journal Information:
- Trans. Am. Nucl. Soc.; (United States), Journal Name: Trans. Am. Nucl. Soc.; (United States) Vol. 55; ISSN TANSA
- Country of Publication:
- United States
- Language:
- English
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A CODES
ACCIDENTS
CALANDRIAS
CANDU TYPE REACTORS
COMPUTER CODES
CONTAINERS
COOLING SYSTEMS
ECCS
ENERGY SYSTEMS
ENGINEERED SAFETY SYSTEMS
HEAVY WATER MODERATED REACTORS
LOSS OF COOLANT
PRESSURE TUBE REACTORS
PRESSURE TUBES
PRIMARY COOLANT CIRCUITS
REACTOR ACCIDENTS
REACTOR COMPONENTS
REACTOR COOLING SYSTEMS
REACTOR CORES
REACTOR PROTECTION SYSTEMS
REACTOR SAFETY
REACTORS
RELIABILITY
SAFETY
THERMAL REACTORS
TUBES