Thermal regimes of high burn-up nuclear fuel rod

Kudryashov, Nikolay A.; Khlunov, A. V.; Chmykhov, Mikhail A.

doi:10.1016/j.cnsns.2009.05.063

Cited by 16 publications

(7 citation statements)

References 28 publications

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“…The Todreas and Kazimi (1993a) and Duderstadt and Hamilton (1976) by solving the energy equation in cylindrical co-ordinates with appropriate boundary conditions. The temperature distribution in nuclear fuel rod taking into account the fuel, the rim-layer, the gap, the film of the zirconium oxide and the cladding has been found in open literature (Kudryashov et al, 2010). Using the numerical and analytical approaches Kudryashov et al (2010) showed that the time taken to have the stationary thermal regime of nuclear fuel rod is less than one minute.…”

Section: Introductionmentioning

confidence: 97%

“…The temperature distribution in nuclear fuel rod taking into account the fuel, the rim-layer, the gap, the film of the zirconium oxide and the cladding has been found in open literature (Kudryashov et al, 2010). Using the numerical and analytical approaches Kudryashov et al (2010) showed that the time taken to have the stationary thermal regime of nuclear fuel rod is less than one minute. They determined exact solutions of the temperature distribution in the fuel rods and analyzed thermal regimes of high burn-up the nuclear fuel rods.…”

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

Thermodynamic analysis of a solid nuclear fuel element surrounded by flow of coolant through a concentric annular channel

Poddar

Chatterjee

Chakravarty

et al. 2015

Progress in Nuclear Energy

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

Thermodynamic analysis of a solid nuclear fuel element surrounded by flow of coolant through a concentric annular channel

Poddar

Chatterjee

Chakravarty

et al. 2015

Progress in Nuclear Energy

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“…They found that there is a limiting value of biot number above which the temperature of the fuel element cannot be decreased. Kudryashov et al used both numerical and analytical approach to determine the temperature distribution in the fuel element during high burnups. They also determined the time required for temperature variation to become steady from the transient state.…”

Section: Introductionmentioning

confidence: 99%

Investigation of dimensionless parameters and geometry effects on heat‐transfer characteristics of liquid sodium flowing over a flat plate

Kaladgi¹,

Afzal²,

Ad³

et al. 2018

Heat Trans. Asian Res.

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To improve the cooling performance of a nuclear fuel element, it is important to appraise the effect of dimensionless parameters and the geometry on heat‐transfer characteristic of sodium flowing over a nuclear fuel element. To fulfill this objective, the effects of geometry, Reynolds number (ReH), conductivity ratio ( N cc ), and dimensionless total heat generation parameter ( Qt) on a two‐dimensional steady flow of liquid coolant flowing over a nuclear fuel element are studied. For this purpose, the stream function‐vorticity formulation method is applied. Full Navier Stokes equations and energy equation for the fluid domain are solved concurrently with conduction equation of fuel element applying finite difference scheme. The pseudotransient form of the vorticity transport and energy equations is solved using the alternating direction implicit method. A line‐by‐line technique is used for other discretized equations. Isotherms are also plotted and studied in detail. From the obtained results it can be concluded that for fixed values of aspect ratio and Re H there exists a critical value of Qt and N cc beyond and below which peak temperature in the fuel element surpasses its tolerable limit. The results can also be applied to minimize the peak temperature in the nuclear fuel element (hot spots).

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“…A similar problem for a uniform distribution of the thermal power released in the peripheral layer with constant temperature of the outer surface of the zirconium cladding is studied in [13]. In the present work, a general boundary condition on the surface of a fuel element is studied: heat transfer between the zirconium cladding and the cooling liquid is taken into account using the Newton-Rikhman law.…”

mentioning

confidence: 98%

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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Thermal regimes of high burn-up nuclear fuel rod

Cited by 16 publications

References 28 publications

Thermodynamic analysis of a solid nuclear fuel element surrounded by flow of coolant through a concentric annular channel

Thermodynamic analysis of a solid nuclear fuel element surrounded by flow of coolant through a concentric annular channel

Investigation of dimensionless parameters and geometry effects on heat‐transfer characteristics of liquid sodium flowing over a flat plate

Numerical modeling of the temperature distribution in a VVER fuel element

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