Simplified distributed parameters BWR dynamic model for transient and stability analysis

Espinosa-Paredes, Gilberto; Nuñez-Carrera, Alejandro; Vázquez–Rodríguez, A.

doi:10.1016/j.anucene.2006.08.009

Cited by 11 publications

(4 citation statements)

References 7 publications

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“…Datos geométricos de una barra de combustible típica de un ensamble de combustible de 10x10 (López & Marco A. Lucatero, 2011) Material de la pastilla: Dióxido de Uranio (UO2) Tabla 2. Correlaciones para propiedades termofísicas de los materiales que integran la barra de combustible (Espinosa-Paredes, Núñez-Carrera, & Vázquez-Rodríguez, 2006) Conductividad térmica combustible Capacidad calorífica volumétrica combustible…”

Section: Introductionunclassified

Solución numérica de la conducción de calor unidimensional en estado transitorio en un elemento de combustible de un reactor tipo BWR mediante diferencias finitas

et al. 2022

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El presente trabajo describe una solución numérica de la distribución de temperaturas en un elemento de combustible de un reactor nuclear tipo BWR, partiendo de la ecuación general de conducción calor en su forma no lineal y asumiendo que las propiedades termofísicas de los materiales que lo integran son funciones que dependen de la temperatura. La solución se basa en el método de diferencias finitas, usando un esquema de discretización en diferencias finitas centradas, tanto para el estado estacionario como para el transitorio. Ambos casos se resuelven con el apoyo del programa Microsoft Excel, usando las herramientas de solución propias de este software para sistemas de ecuaciones lineales y el desarrollo de funciones embebidas en Excel para representar la dependencia de la temperatura en las propiedades termofísicas. Se resuelven dos escenarios de estado transitorio, el primero se refiere a un apagado del reactor (generación interna de calor nula) y el segundo, a un cambio en el coeficiente de transferencia de calor por convección. Para ambos escenarios de simulación, el análisis de resultados se realiza en forma cualitativa, resultando en un comportamiento apropiado, de acuerdo con lo esperado.

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Section: Introductionunclassified

Solución numérica de la conducción de calor unidimensional en estado transitorio en un elemento de combustible de un reactor tipo BWR mediante diferencias finitas

et al. 2022

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“…This dependence has been intensively studied for prolonged lifetime of existing reactors. There are many papers in which the authors studied the different aspects of this problem [2][3][4][5][6][7]. Yapici et al [2] investigated the maximum temperatures in centerline of the fuel rod for different clad outer surface temperatures, melting points of the fuel materials, temporal heat generation, temperature distribution in the nuclear fuel rod and temporal variation of the neutronic data during rejuvenation periods.…”

Section: Introductionmentioning

confidence: 99%

“…We have taken physical parameters and dependencies of the densities and the specific heat capacities on temperature for the fuel, the gap and the cladding from the papers [1,6,7] . Heat conductivities for the fuel and for the rim layer could be expressed by a classical phonon transport model [24][25][26][27]…”

Section: Introductionmentioning

confidence: 99%

Thermal regimes of high burn-up nuclear fuel rod

Kudryashov¹,

Khlunov²,

Chmykhov³

2010

Communications in Nonlinear Science and Numerical Simulation

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The temperature distribution in the nuclear fuel rods for high burn-up is studied. We use the numerical and analytical approaches. It is shown that the time taken to have the stationary thermal regime of nuclear fuel rod is less than one minute. We can make the inference that the behavior of the nuclear fuel rod can be considered as a stationary task. Exact solutions of the temperature distribution in the fuel rods in the stationary case are found. Thermal regimes of high burn-up the nuclear fuel rods are analyzed.Comment: 24 pages, 9 figure

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“…The heat-transfer coefficient H is found according to the relation [16] H = 0.023Re 0.8 Pr 0.4 k/D h , where Re = GD h /μ is the Reynolds number, Pr = μC p /k is the Prandtl number, D h is the hydraulic diameter, k is the thermal conductivity of water, C p is the specific heat of water at constant pressure, μ is the dynamic viscosity of water, and G is the flow density of the cooling liquid. The reference data in [17] were used to determine the coefficient of heat-transfer H = 2936.8 J/(sec·m 2 ·K) at water pressure P = 15.7 MPa and temperature T = 488 K.…”

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confidence: 99%

Numerical modeling of the temperature distribution in a VVER fuel element

et al. 2010

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The temperature distribution in a VVER fuel element with deep burnup of nuclear fuel is studied. Numerical and analytical methods are used. It is shown that a stationary temperature distribution is established in no longer than 1 min. Analytical methods are used to obtain the temperature dependence of the radius of a fuel element in a stationary regime.One way to realize down trending fuel-cycle costs in nuclear power is to increase the burnup of heavy nuclei. Higher burnup is desirable from the standpoint of a positive solution to economic questions as well as to draw high-enrichment uranium and plutonium into large-scale nuclear power, since the transition to deep burnup and long fuel run is impossible without increasing the enrichment of or adding plutonium to uranium fuel [1].With deep burnup of oxide nuclear fuel, a large change occurs in the structural-phase state, chemical composition, and density of the fuel kernel of a fuel element [2]. As fission products accumulate, the oxygen potential changes and new localized phases precipitate [3,4] and the thickness of the most highly damaged surface layer of a fuel pellet increases [5,6]. In the peripheral layer, the initial grains with typical size ~15 μm disperse under irradiation into 0.2-0.3 μm subgrains and low-density dislocations. The result is that a fine-grain structure with elevated porosity of quite large size (micron) forms in the surface layer of the pellets as burnup increases and fission products accumulate. For example, with average uranium burnup 105 GW·days/tons the local burnup in the surface layer of a pellet reaches 300 GW·days/tons. In the process, a so-called ultra-high burnup structure [7-9], where the pore size reaches 15 μm as a result of coalescence or migration of bubbles, forms, increasing the local porosity to 22% [10].The thermophysical processes in the fuel composition and in a fuel element as a whole are of scientific and practical interest. For oxide nuclear fuel, as burnup increases, the thermal conductivity decreases noticeably as a result of the accumulation of soluble fission products and the formation of radiation-induced defects due to the action of fission products. This decrease of the thermal conductivity is especially strongly manifested at temperatures below 1000 K.The strongest changes can occur in the surface zone. It is important to know the particulars of and regularities in the variations of the state and properties of the fuel composition to refine the fuel element design, choose the operating regimes of the reactor, and predict the behavior of fuel intended for deep burnup.For a fuel element as a source of nuclear energy, the thermal conductivity of the materials and heat transfer in the radial direction are important but difficult to determine experimentally. For this reason, it is of interest to perform a theoretical analysis and modeling of the heat transfer taking account of the surface layer, appearance and growth of an oxide layer on the zirconium cladding, and decrease of the gap between the fuel composit...

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Simplified distributed parameters BWR dynamic model for transient and stability analysis

Cited by 11 publications

References 7 publications

Solución numérica de la conducción de calor unidimensional en estado transitorio en un elemento de combustible de un reactor tipo BWR mediante diferencias finitas

Solución numérica de la conducción de calor unidimensional en estado transitorio en un elemento de combustible de un reactor tipo BWR mediante diferencias finitas

Thermal regimes of high burn-up nuclear fuel rod

Numerical modeling of the temperature distribution in a VVER fuel element

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