Effect of Gd2O3Dispersion on the Thermal Conductivity of UO2

Iwasaki, Kouta; Matsui, Tsuneo; Yanai, Koichi; Yuda, Ryouichi; Arita, Yuji; Nagasaki, Takanori; Yokoyama, Noboru; Tokura, Ichiro; Une, Katsumi; Harada, Koji

doi:10.1080/18811248.2007.9711574

Cited by 26 publications

(7 citation statements)

References 14 publications

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“…UO 2 has a different thermal expansion coefficient of 12 × 10 −6 /°C, and the interfacial cracks are expected to form in UO 2 oxide pellet containing lumped Gd 2 O 3 with a high initial density. 3 Durazzo et al 49 investigated the effect of Gd 2 O 3 phase transformation on the sintering of Gd 2 O 3 -mixed UO 2 fuel pellets and found that no interfacial cracks were developed by the phase transformation of Gd 2 O 3 . Similar cracks were also observed in the UO 2 -ThO 2 duplex pellet because of the difference in the densification of UO 2 and ThO 2 , respectively.…”

Section: Fabrication Of Oxide Pellets Containing Lumped Gd 2 Omentioning

confidence: 99%

Fabrication of oxide pellets containing lumped Gd₂O₃using Y₂O₃-stabilized ZrO₂for burnable absorber fuel applications

et al. 2018

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Summary In this paper, the fabrication of novel burnable absorber fuel concepts with oxide pellets, containing either a lumped Gd2O3 rod, a mini‐pellet, or a spherical particle in the centerline of the oxide pellet, is investigated to propose the lumped Gd2O3 burnable absorber fuel concept to improve nuclear fuel performance with longer fuel cycle lengths and better fuel utilization. The unique characteristic of the lumped Gd2O3 burnable absorber fuel is its high spatial self‐shielding factor that reduces its burnout rate and, therefore, improves the reactivity control. Oxide pellets containing lumped Gd2O3 were fabricated by using a combination of cold isostatic pressing and microwave sintering at 1500°C to understand the potential technical issues in the fabrication of duplex burnable absorber fuel. The effect of the sintering temperature on the densification and phase transformation of 8 wt.% yttria‐stabilized zirconia, a surrogate for UO2, was investigated. Spherical Gd2O3 particles were fabricated by the drip casting of a Gd2O3‐based Na alginate solution. The fabrication of duplex oxide pellets by using presintered Gd2O3 mini‐pellets resulted in internal cracks at the interface between the Gd2O3 and 8 wt.% yttria‐stabilized zirconia layers because of the mismatch of their densification. However, the formation of interfacial cracks was eliminated by controlling the initial sintered density of the lumped Gd2O3.

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Section: Fabrication Of Oxide Pellets Containing Lumped Gd 2 Omentioning

confidence: 99%

Fabrication of oxide pellets containing lumped Gd₂O₃using Y₂O₃-stabilized ZrO₂for burnable absorber fuel applications

et al. 2018

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“…In fast reactors, the centerline temperature of MOX fuel pellets increases up to the melting temperature of the MOX and a hole appears in the central part of the pellet early in the irradiation period. This is caused by the high heat flux and low thermal conductivity of the MOX fuel matrix [17][18][19]. The high heat flux combined with a steep temperature gradient has other effects, including the formation of cracks, redistribution of Fission Product (FP) and Trans-Uranium (TRU) atoms, the formation of precipitates of fuel and FP atoms in the middle part of the pellet, and the formation of a so-called Joint Oxide Gaine (JOG) at the pellet-clad interface.…”

Section: Calculation Of the Thermal Conductivity Of Particlementioning

confidence: 99%

“…The heat source for the MOX matrix and the external temperature of the pellet was fixed for the calculations. In the present study it is assumed that the thermal conductivity of the dispersed particles is ten times higher than that of the MOX matrix [17][18][19].…”

Section: Calculationmentioning

confidence: 99%

Study on Detailed Calculation and Experiment Methods of Neutronics, Fuel Materials, and Thermal Hydraulics for a Commercial Type Japanese Sodium-Cooled Fast Reactor

Takeda

Rooijen

Yamaguchi

et al. 2012

Science and Technology of Nuclear Installations

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This paper discusses the objectives and results of a multiyear R&D project to improve the modeling accuracy for the detailed calculation of the Japanese Sodium-cooled Fast Reactor (JSFR), although the preliminary design of JSFR is prepared using conventional methods. For detailed design calculations, new methods are required because the JSFR has special features, which cannot be accurately modeled with existing codes. An example is the presence of an inner duct in the fuel assemblies. Therefore, we have developed new calculational and experimental methods in three areas: (1) for neutronics, we discuss the development of methods and codes to model advanced FBR fuel subassemblies, (2) for fuel materials, modeling and measurement of the thermal conductivity of annular fuel is discussed, and (3) for thermal hydraulics, we describe advances in modeling and calculational models for the intermediate heat exchanger and the calculational treatment of thermal stratification in the hot plenum of an FBR under low flow conditions. The new methods are discussed and the verification tests are described. In the validation test, measured data from the prototype FBR Monju is partly used.

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“…Research is also conducted in terms of assessing the behavior of uranium-gadolinium fuel during homogeneous mixing of elements: when gadolinium is added to the fuel, its thermal conductivity changes, affecting the design characteristics. At a Gd 2 O 3 concentration of about 10% and a pellet density of 10.62 g/cm 3 , high thermal conductivity is maintained (Iwasaki et al 2009). Further changes in these values lead to a decrease in this parameter value.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Burnable Absorber Arrangement on the VVER(1200 Fuel Assembly Neutronic Performance

Vnukov

Kolesov

Zhavoronkova

et al. 2021

YadEn

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Optimizing the use of fuel in a power reactor is a task of current concern. However, little attention has been given to investigating the dependences among the enrichment used, the content of gadolinium oxide in fuel elements, and the life time in combination with assessing the efficiency of using Gd fuel elements with different Gd 2 O 3 contents.The paper considers fuel assembly (FA) versions for VVER-1200 reactors having different enrichments for fuel elements, including those with Gd, and different contents of gadolinium oxide in fuel. A comparative analysis is presented for assemblies with homogeneous Gd 2 O 3 arrangements in each fuel element and with profiled Gd 2 O 3 arrangements. In the latter case, profiling depends on the neutron flux density in the layer which includes Gd fuel elements. This suggests that the arrangement of gadolinium oxide proportionally to the neutron flux density will improve the FA neutronic performance.The results were obtained using SERPENT (a continuous-energy multi-purpose three-dimensional Monte Carlo particle transport code). The assemblies with the used parameters for a 12-month fuel cycle have shown the method under consideration to be inefficient for a period of over 300 eff. days. With increased enrichment and content of gadolinium oxide, the use of profiled versions has turned out to be more rational for longer periods (up to 900 eff. days). Therefore, this phenomenon is relevant for the reactor life, whereas it proves to be insignificant for the fuel life. A complex relationship is noted between the gadolinium and uranium content in an assembly and the effective multiplication factor for the profiled and standard assemblies. This relationship requires further detailed consideration.

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Effect of Gd₂O₃Dispersion on the Thermal Conductivity of UO₂

Cited by 26 publications

References 14 publications

Fabrication of oxide pellets containing lumped Gd₂O₃using Y₂O₃-stabilized ZrO₂for burnable absorber fuel applications

Fabrication of oxide pellets containing lumped Gd₂O₃using Y₂O₃-stabilized ZrO₂for burnable absorber fuel applications

Study on Detailed Calculation and Experiment Methods of Neutronics, Fuel Materials, and Thermal Hydraulics for a Commercial Type Japanese Sodium-Cooled Fast Reactor

Effect of the Burnable Absorber Arrangement on the VVER(1200 Fuel Assembly Neutronic Performance

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Effect of Gd2O3Dispersion on the Thermal Conductivity of UO2

Cited by 26 publications

References 14 publications

Fabrication of oxide pellets containing lumped Gd2O3using Y2O3-stabilized ZrO2for burnable absorber fuel applications

Fabrication of oxide pellets containing lumped Gd2O3using Y2O3-stabilized ZrO2for burnable absorber fuel applications

Study on Detailed Calculation and Experiment Methods of Neutronics, Fuel Materials, and Thermal Hydraulics for a Commercial Type Japanese Sodium-Cooled Fast Reactor

Effect of the Burnable Absorber Arrangement on the VVER(1200 Fuel Assembly Neutronic Performance

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Effect of Gd₂O₃Dispersion on the Thermal Conductivity of UO₂

Fabrication of oxide pellets containing lumped Gd₂O₃using Y₂O₃-stabilized ZrO₂for burnable absorber fuel applications

Fabrication of oxide pellets containing lumped Gd₂O₃using Y₂O₃-stabilized ZrO₂for burnable absorber fuel applications