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Abstract
An experimental work was carried out on a passive containment cooling system (PCCS) test facility where the effects of change in secondary cooling pool water level and the presence of a noncondensable on the PCCS heat transfer characteristics were investigated. Two condensation flow regimes, complete condensation and flow-through condensation relevant to initial and late stages of PCCS operation, were investigated where secondary cooling pool water level decreases with time. A single tube and a tube bundle test section were used. Steady-state tests with half full and half secondary pool levels were performed using single and four-tube bundle test sections. Transient tests were carried out on the tube bundle test section where the secondary pool water decreases continuously due to boil-off. Transient tests carried out with secondary pool water level change showed that the system pressure for complete condensation mode increases with decrease in water level; however, rate of condensation is almost constant. If the PCCS is operated in through-flow mode the system pressure (primary side pressure) is constant; however, the condensate rate decreases, indicating that some of the steam does not condense. A decrease in pool water level to the top header initially decreases the inlet steam pressure, indicating slight heat transfer enhancement due to efficient cooling of PCCS tubes due to two-phase mixture. When the water level is below three-fourths of the tube height the inlet steam pressure increases with decrease in the water level, indicating decrease in PCCS heat transfer rate. The presence of a noncondensable also reduced PCCS condensation heat transfer.
NOMENCLATURE
| A | = | area (m2) |
| d | = | diameter (m) |
| H | = | tank height or length (m) |
| h | = | heat transfer coefficient (kW/m2-s) |
| hfg | = | latent heat of vaporization (kJ/kg) |
| k | = | thermal conductivity (W/m°C) |
| = | mass flow rate (kg/s) | |
| p | = | tube bundle pitch (m) |
| = | condensation heat transfer rate (kW) | |
| t | = | time (s) |
| T | = | temperature (°C) |
| U | = | overall heat transfer coefficient (kW/m2-s) |
| Wair | = | noncondensable (air) mass fraction |
Greek Symbols
| Δ | = | difference or change |
| ρ | = | density |
Subscripts
| CT | = | condensate tank |
| c | = | condensation, condensate |
| i | = | tube inner |
| o | = | tube outer |
| P | = | pool |
| SAT | = | at saturation |
| sec | = | secondary side |
| st | = | steam |
| tube | = | condenser tube |
| Wi | = | inside tube wall |
| Wo | = | outside tube wall |
| w | = | condenser tube wall |
Additional information
Funding
Notes on contributors
Shripad T. Revankar
Shripad T. Revankar is a professor of nuclear engineering and Director of the Multiphase and Fuel Cell Research Laboratory in the School of Nuclear Engineering at Purdue University. He is also WCU Visiting Professor at Pohang University of Science and Technology in the Division of Advanced Nuclear Engineering in South Korea. He received his B.S. (1975), M.S. (1977), and Ph.D. (1983) in physics from Karnatak University, India, M.Eng. (1982) in Nuclear Engineering from McMaster University, Canada, and postdoctoral training at Lawrence Berkeley Laboratory and at the Nuclear Engineering Department of University of California, Berkeley, from 1984 to 1987. His research interests are in the areas of nuclear reactor thermal hydraulics and safety, multiphase heat transfer, multiphase flow in porous media, instrumentation and measurement, fuel cell design, simulation and power systems, and nuclear hydrogen generation. He has published more than 250 technical papers in archival journals and conference proceedings. He is active member of the AIChE, ANS, AAAS, ECS,and ASEE. He is on the editorial board of several journals, including Heat Transfer Engineering. He is a fellow of the ASME.
Wenzhong Zhou
Wenzhong Zhou is an assistant professor in the Department of Mechanical and Biomedical Engineering at City University of Hong Kong. He received his B.S. (1996) and M.S. (2002) in heating, ventilation, and air conditioning (HVAC) engineering from Tianjin University, China, and Ph.D. (2010) in nuclear engineering from Purdue University. Before his current position, he worked as a research associate at Los Alamos National Laboratory. He is a member of the ANS, ASME, ASHRAE, and Sigma Xi. His research interests are in heat transfer, and reactor safety. He serves as an associate editor for Journal of Power Technologies, Energy and Environment Research, and Mechanical Engineering Research.