Numerical Simulation Study on the Air/Water Counter- current Flow Limitation in Nuclear Reactors

Authors

  • youssef morghi Doutorado em Ciência e Tecnologia das Radiações, Minerais e Materiais
  • Amir Zacarias Mesquita Pesquisador de Produtividade e Desenvolvimento Tecnológico - DT/CNPq

DOI:

https://doi.org/10.15392/bjrs.v8i3B.610

Keywords:

Countercurrent Fow Limitation (CCFL), Computational fluid dynamics, LOCA, PWR.

Abstract

After a loss-of-coolant accident (LOCA) in a Pressurized Water Reactor (PWR), the temperature of the fuel elements cladding increases dramatically due to the heat produced by the fission products decay, which is not adequately
removed by the vapor contained in the core. In order to avoid this sharp rise in temperature and consequent melting of the core, the Emergency Core Cooling System is activated. This system initially injects borated water from accumulator
tanks of the reactor through the inlet pipe (cold leg) and the outlet pipe (hot leg), or through the cold leg only, depending on the plant manufacturer. Some manufacturers add to this, direct injection into the upper plenum of the
reactor. The penetration of water into the reactor core is a complex thermofluidodynamic process because it involves the mixing of water with the vapor contained in the reactor, added to that generated in the contact of the water with the still hot surfaces in various geometries. In some critical locations, the vapor flowing in the opposite direction of the water can control the penetration of this into the core. This phenomenon is known as Countercurrent Flow Limitation (CCFL) or Flooding, and it are characterized by the control that a gas exerts in the liquid flow in the opposite direction.
This work presents a proposal to use a CFD to simulate the CCFL phenomenon. Numerical computing can provide important information and data that is difficult or expensive to measure or test experimentally. Given the importance of
computational science today, it can be considered a third and independent branch of science on an equal footing with the theoretical and experimental sciences.

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Author Biography

  • youssef morghi, Doutorado em Ciência e Tecnologia das Radiações, Minerais e Materiais
    Departamento de Tecnologia das Radiações, Minerais e Materiais

References

Al Issa, S.; Macian, R. Experimental investigation of countercurrent flow limitation (CCFL) in a large-diameter hot-leg geometry: A detailed description of CCFL mechanisms, flow patterns and high-quality HSC imaging of the interfacial structure in a 1/3.9 scale of PWR geometry. Nucl. Eng.

Des. V. 280, p. 550-563, 2014.

Navarro, M.A. Study of countercurrent flow limitation in a horizontal pipe connected to an inclined one. Nucl. Eng. Des. V. 235, p. 1139-1148, 2005.

Al Issa, S.; Macian, R. A review of CCFL phenomenon. Annals of Nuclear Energy. V. 38, p. 1795-1819, 2011.

Chistophe V; et Al. Counter –current flow limitation in a model of the hot leg of a PWR – comparison between air/water and steam/water experiments. Nuc.Eng.Des. V. 245, p. 113-124, 2012.

Deendarlianto; Thomas Hohne; Dirk Lucas; Karen Vierow; Gas-liquid countercurrent two-phase flow in a PWR hot leg: A comprehensive research review. Nuc. Eng.Des. V. 243, p. 214-233, 2011.

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Published

2021-02-13

Issue

Section

XX Meeting on Nuclear Reactor Physics and Thermal Hydraulics (XX ENFIR)

How to Cite

Numerical Simulation Study on the Air/Water Counter- current Flow Limitation in Nuclear Reactors. Brazilian Journal of Radiation Sciences, Rio de Janeiro, Brazil, v. 8, n. 3B (Suppl.), 2021. DOI: 10.15392/bjrs.v8i3B.610. Disponível em: https://bjrs.org.br/revista/index.php/REVISTA/article/view/610.. Acesso em: 18 dec. 2024.

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