Thermal stratification and striping in a model pressurizer surge line

Conference · Wed Nov 01 04:00:00 EST 1989 · Transactions of the American Nuclear Society; (United States)

OSTI ID:5486928

Morgan, C D; Fitzgerald, D W; Odgen, C W; Joynt, M A; Raiford, P G ^[1]

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1. Virginia Military Institute, Lexington (USA)

During the start-up of nuclear plant, hot water from the pressurizer slowly flows through the surge line to the primary system. Under some conditions, the hotter water will ride on top of the cooler water from the primary system. The resulting stratified flow has an oscillating interface. The temperature differences between the top and bottom of the surge line can cause significant deformation due to differential thermal expansion. The oscillating temperatures at the interface (thermal striping) cause thermal stresses and high-cycle fatigue. A scale model of the pressurizer surge line in a typical Babcock Wilcox pressurized water reactor was constructed to study thermally stratified flow and striping. The model closely matched elevation changes and horizontal lengths, but the inside diameter of the pipe was only 3 in. compared to 8.75 in. in the plant. The horizontal sections contained clear acrylic pipe. The hot and cold water were dyed different colors so that the interface would be clearly visible. The tests were performed at atmospheric pressure with hot water at {approximately}145{degree}F and cold water at {approximately}70{degree}F. Salt was added to the cold water so that density differences up to 10 lb{sub m}/ft{sup 3} could be obtained. The density and viscosity of the salt water were measured before starting the test. Results are described in this paper.

• OSTI ID: 5486928
• Report Number(s): CONF-891103--
• Conference Information: Journal Name: Transactions of the American Nuclear Society; (United States) Journal Volume: 60
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210200* -- Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
COOLING SYSTEMS
DEFORMATION
ENERGY SYSTEMS
EXPANSION
FATIGUE
FLOW RATE
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
OPERATION
PRESSURIZERS
PRIMARY COOLANT CIRCUITS
PWR TYPE REACTORS
REACTOR COMPONENTS
REACTOR COOLING SYSTEMS
REACTOR OPERATION
REACTOR START-UP
REACTORS
SALTS
START-UP
STRATIFICATION
STRESSES
SURGES
TEMPERATURE DEPENDENCE
THERMAL EXPANSION
THERMAL FATIGUE
THERMAL STRESSES
TURBULENCE
VISCOSITY
WATER COOLED REACTORS
WATER MODERATED REACTORS