Use este identificador para citar ou linkar para este item: http://carpedien.ien.gov.br:8080/handle/ien/2198
Tipo: conferenceObject
Título: TRANSIENT HEAT TRANSFER ANALYSIS UP TO DRYOUT IN 3D FUEL RODS UNDER UNIDEAL CONDITIONS THROUGH THE DEVELOPMENT OF A COMPUTER CODE
Autor(es): MARTINS, Rodolfo I.
AFFONSO, Renato R. W.
MOREIRA, Maria de Lourdes
SAMPAIO, Paulo A. B. De
Resumo: In this paper we analyze a conjugated transient heat transfer problem consisting of a nuclear reactor’s fuel rod and its intrinsic coolant channel. Our analysis is made possible through a computer code being developed at the Instituto de Engenharia Nuclear (IEN/CNEN). This code is meant to study the temperature behavior in fuel rods which exhibit deviation from their ideal conditions, that is, rods in which the cladding is deformed or the fuel is dislocated. It is also designed to avoid the use of the computationally expensive Navier-Stokes equations. For these reasons, its physical model has as basis a three-dimensional fuel rod coupled to a one-dimensional coolant channel, which are discretized using the finite element method. Intending to study accidental conditions in which the coolant (light water) transcends its saturation temperature, turning into vapor, a homogeneous mixture is used to represent the two-phase flow, and so the coolant channel’s energy equation is described using enthalpy. Owing to the fact that temperature and enthalpy are used in the physical model, it became impractical to generate a fully coupled method for solving the pertinent equations. Thus, the conjugated heat transfer problem is solved in a segregated manner through the implementation of an iterative method. Finally, as study cases for this paper we present analyses concerning the behavior of the hottest fuel rod in a Pressurized Water Reactor during a shutdown wherein the residual heat removal system is lost (loss of the reactor’s coolant pumps). These studies contemplate cases in which the fuel rod’s geometry is ideal or curved. Analyses are also performed for two circumstances of positioning of the fuel inside the rod: concentric and eccentric.
In this paper we analyze a conjugated transient heat transfer problem consisting of a nuclear reactor’s fuel rod and its intrinsic coolant channel. Our analysis is made possible through a computer code being developed at the Instituto de Engenharia Nuclear (IEN/CNEN). This code is meant to study the temperature behavior in fuel rods which exhibit deviation from their ideal conditions, that is, rods in which the cladding is deformed or the fuel is dislocated. It is also designed to avoid the use of the computationally expensive Navier-Stokes equations. For these reasons, its physical model has as basis a three-dimensional fuel rod coupled to a one-dimensional coolant channel, which are discretized using the finite element method. Intending to study accidental conditions in which the coolant (light water) transcends its saturation temperature, turning into vapor, a homogeneous mixture is used to represent the two-phase flow, and so the coolant channel’s energy equation is described using enthalpy. Owing to the fact that temperature and enthalpy are used in the physical model, it became impractical to generate a fully coupled method for solving the pertinent equations. Thus, the conjugated heat transfer problem is solved in a segregated manner through the implementation of an iterative method. Finally, as study cases for this paper we present analyses concerning the behavior of the hottest fuel rod in a Pressurized Water Reactor during a shutdown wherein the residual heat removal system is lost (loss of the reactor’s coolant pumps). These studies contemplate cases in which the fuel rod’s geometry is ideal or curved. Analyses are also performed for two circumstances of positioning of the fuel inside the rod: concentric and eccentric.
In this paper we analyze a conjugated transient heat transfer problem consisting of a nuclear reactor’s fuel rod and its intrinsic coolant channel. Our analysis is made possible through a computer code being developed at the Instituto de Engenharia Nuclear (IEN/CNEN). This code is meant to study the temperature behavior in fuel rods which exhibit deviation from their ideal conditions, that is, rods in which the cladding is deformed or the fuel is dislocated. It is also designed to avoid the use of the computationally expensive Navier-Stokes equations. For these reasons, its physical model has as basis a three-dimensional fuel rod coupled to a one-dimensional coolant channel, which are discretized using the finite element method. Intending to study accidental conditions in which the coolant (light water) transcends its saturation temperature, turning into vapor, a homogeneous mixture is used to represent the two-phase flow, and so the coolant channel’s energy equation is described using enthalpy. Owing to the fact that temperature and enthalpy are used in the physical model, it became impractical to generate a fully coupled method for solving the pertinent equations. Thus, the conjugated heat transfer problem is solved in a segregated manner through the implementation of an iterative method. Finally, as study cases for this paper we present analyses concerning the behavior of the hottest fuel rod in a Pressurized Water Reactor during a shutdown wherein the residual heat removal system is lost (loss of the reactor’s coolant pumps). These studies contemplate cases in which the fuel rod’s geometry is ideal or curved. Analyses are also performed for two circumstances of positioning of the fuel inside the rod: concentric and eccentric.
Palavras-chave: INAC 2017
INAC 2017
INAC 2017
Idioma: eng
eng
eng
eng
País: Brasil
Brasil
Brasil
Brasil
Editor: Instituto de Engenharia Nuclear
Instituto de Engenharia Nuclear
Instituto de Engenharia Nuclear
Instituto de Engenharia Nuclear
Sigla da Instituição: IEN
IEN
IEN
IEN
Tipo de Acesso: openAccess
URI: http://carpedien.ien.gov.br:8080/handle/ien/2198
Data do documento: Out-2017
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