Category Archives: Natural circulation data and methods for advanced water cooled nuclear power plant designs


1.2.1. Single phase flow In Section 2 several nuclear reactor designs as well as natural circulation applications have been described. The single phase natural circulation flow is driven by a gravity head induced by coolant density differences; the mass flow is established according to the balance between driving head and flow resistance losses. Because the (one component) density is a […]

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Stable Two-Phase NC (TPNC)

TPNC regime occurs as a consequence of coolant loss from the primary system. Owing to this, both driving and resistant forces increase when decreasing mass inventory of primary system. Assigned the typical geometrical layout of PWR, the former effect, i. e. increase of driving forces, is prevalent at small decreases of mass inventories. The opposite occurs for larger decreases of […]

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. Steady state behaviour of two-phase systems

For testing the scaling laws, a two-phase natural circulation loop as shown in Fig. 11 was constructed. The loop was made of 50 mm NB (2” Sch 80) pipes except for the separator which is 150 mm NB (6” Sch 120) pipe. The separated steam is condensed and the condensate is returned to the separator. The vertical heater is direct […]

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Severe accidents

After the accidents in TMI-2 and Chernobyl, the study of phenomena, reactor system, and containment behaviour for sequences with core melts became a major research area. Compared to phenomena under DBA conditions, the phenomena that are present during accident sequences with core melt are very complex and, evidently, much less understood. The main phenomena influencing containment behaviour are

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High pressure natural convection loop

CAPCN resembles CAREM in the primary loop and steam generators, while the secondary loop is designed just to produce adequate boundary conditions for the heat exchanger. Water enters the heated section from the lower plenum. The nuclear core is reproduced by electric heaters. The heated water flows up through the riser to the upper plenum where a vapor interphase exists. […]

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The Instrumentation Development

TOPFLOW will be equipped with advanced two-phase instrumentation mainly and adapted and developed in Rossendorf, such as wire-mesh sensors, needle-shaped conductivity probes with integrated thermocouple, gamma and X-ray tomography and passive ultrasonic droplet probes. Additionally, laser-doppler anemometry and a phase-doppler particle analyser are available. Two of these devices, the needle-shaped conductivity probes with integrated thermocouple and the wire-mesh sensors will […]

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