Sensitivity study of PWR upper vessel flow and phenomena using RELAP5-3D

Journal Article · Fri Jul 01 00:00:00 EDT 2016 · Transactions of the American Nuclear Society

OSTI ID:23042759

Crook, Timothy; Vaghetto, Rodolfo; Vanni, Alessandro; Hassan, Yassin A. ^[1]

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1. Texas A and M University, Department of Nuclear Engineering 3133 TAMU, College Station, TX 77843-3133 (United States)

During normal pressurized water reactor (PWR) operation, water enters the reactor pressure vessel (RPV) from the cold leg and exits through the hot leg. While most of this water flows through the downcomer and reactor core, a number of other flow paths exist, including the core baffle/bypass and the upper plenum spray. The upper plenum sprays normally account for a small fraction (less than 10%) of the total inlet flow, and provide cooling to the upper vessel dome and instrumentation/control rod channels. In the event of a loss-of-coolant accident (LOCA), especially one with core blockage, this alternative flow path may play a key role in maintaining core coolability. Because of the possible safety implications of the upper vessel flow, it is important to ensure the models used to simulate this region of the vessel are accurate. In this study, the model was altered to better reflect the internal flow path of the upper head and this was compared to the reference model. The simulation of interest is a hot leg double-ended guillotine (HL DEG) break followed later by a full blockage of the core and core bypass. In this scenario, the coolant can only reach the core through the upper spray bypass, so its impact on core coolability can be clearly seen. (authors)

• OSTI ID: 23042759
• Journal Information: Transactions of the American Nuclear Society, Vol. 115; Conference: 2016 ANS Winter Meeting and Nuclear Technology Expo, Las Vegas, NV (United States), 6-10 Nov 2016; Other Information: Country of input: France; 3 refs.; available from American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (US); ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
97 MATHEMATICAL METHODS AND COMPUTING
BAFFLES
BYPASSES
COMPUTERIZED SIMULATION
CONTROL ELEMENTS
COOLANTS
COOLING
LOSS OF COOLANT
PRESSURE VESSELS
PWR TYPE REACTORS
REACTOR CORES
REACTOR OPERATION
REACTOR SAFETY
SENSITIVITY ANALYSIS
SPRAYS
WATER