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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-472-4

ISBN Online: 978-1-56700-471-7

3rd Thermal and Fluids Engineering Conference (TFEC)
March, 4–7, 2018, Fort Lauderdale, FL, USA

CFD analysis of thermal hydraulic behavior in moderator of PHWR

Get access (open in a dialog) pages 391-394
DOI: 10.1615/TFEC2018.cmd.021497

Abstract

The moderator of the Pressurized Heavy Water Reactor (PHWR) is performed to remove the heat from the reactor in the event of a large break loss of coolant accident. The reactor coolant system of Wolsong unit 2 has a shape surrounding 380 separate fuel tubes, and the flow pattern shows as a mixture of natural circulation and forced circulation. Thus, it is difficult to calculate the local temperature and sub-cooling margins if the existing 1D reactor system analysis codes are used. Therefore, CFD analyses were performed for the analysis of thermal hydraulic behaviors inside the moderator. The actual geometry of the moderator is modelled and the flow rate and temperature of the moderator cooling system are modelled as the boundary conditions. To improve the quality of the mesh, the structured mesh was used. Several turbulent models and buoyancy models were reviewed by comparing with experimental results. During the large break loss of coolant accident, the thermal removal load of moderator was calculated through the simulating results using reactor system analysis code (MARS-KS-CANDU). The local temperature distribution and sub-cooling margin of the fuel channel was calculated by CFD analyses using the calculated thermal loads. Such analysis results are available for safety review of the adequacy of the safety functions of the moderator cooling system.