Thermal conductivities of hypostoichiometric (U, Pu, Am)O2−x oxide

Morimoto, Kyoichi; Kato, Masato; Ogasawara, Masahiro; Kashimura, Motoaki

doi:10.1016/j.jnucmat.2007.09.003

Cited by 43 publications

(26 citation statements)

References 25 publications

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“…In previous works, the effects of Np and Am addition on the thermal conductivities of MOX were measured at temperatures of less than 1,873 K, 12,13) and the O=M ratio dependence of thermal conductivity was investigated at temperatures of less than 2,273 K. 14) From these results, Eq. (1) was derived.…”

Section: Thermal Conductivitiesmentioning

confidence: 99%

“…Physical property measurements, fuel pellet preparation tests, and irradiation tests of Np-and Am-bearing MOX (Np/Am-MOX) fuels have been carried out as a part of the development. [4][5][6][7][8][9][10][11][12][13][14][15][16][17] To develop such new fuels, it is essential to evaluate irradiation behavior. However, irradiation data is little in the early phase of development.…”

Section: Introductionmentioning

confidence: 99%

“…[18][19][20] However, the physical properties of MOX containing 0-3% Am and 0-12% Np have been measured in recent studies, and it was found that the effect of Np and Am addition on the properties was small. [7][8][9][10][11][12][13][14][15][16][17] In this work, the physical properties of Np/Am-MOX were evaluated, and the irradiation behavior was analyzed by using those properties, which contribute to the development of the model for describing irradiation behavior.…”

Section: Introductionmentioning

confidence: 99%

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Physical Properties and Irradiation Behavior Analysis of Np- and Am-Bearing MOX Fuels

Kato

Maeda

Ozawa

et al. 2011

Journal of Nuclear Science and Technology

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The physical properties and irradiation behavior of Np-and Am-bearing MOX were evaluated for the development of advanced fast reactor fuels. The physical properties, lattice parameter, melting temperature, thermal conductivity, and oxygen potential of the fuels were described as functions of Np content, Am content, and oxygen-to-metal (O=M) ratio, and the effect of a few percent Np and Am addition into MOX on those properties was found to be negligibly small. The irradiation tests of fuel pellets having O=M ratios of 1.98 or 1.96 were carried out at a high linear heat rate of about 430 W/cm for 24 h. The redistributions of actinide element and oxygen were analyzed by using the physical properties for Np-and Am-bearing MOX, and the maximum temperatures of the pellets were estimated. The maximum temperatures of the pellets of O=M ¼ 1:96 and 1.98 were estimated to be 2,701 and 2,510 K, respectively. The analysis result showed that the higher maximum temperature in the low-O=M pellet was caused by the low thermal conductivity in the outer region of the pellets, and the maximum temperatures of the pellets did not exceed their melting temperatures. In the results of postirradiation examination, no trace of melting was observed.

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Section: Thermal Conductivitiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Physical Properties and Irradiation Behavior Analysis of Np- and Am-Bearing MOX Fuels

Kato

Maeda

Ozawa

et al. 2011

Journal of Nuclear Science and Technology

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“…Work has also been performed in the JOYO reactor by JAEA to study the effect of minor actinide additions on the thermal conductivity of MOX fuel. Again, results were encouraging-Am additions of up to 3 wt% only slightly reduce the thermal conductivity of MOX fuel (Morimoto et al, 2008). Nevertheless, it is clear that significantly more work is required before any licensing case could be made for MOX fuel containing actinides.…”

Section: Ivc2 Thermophysical Propertiesmentioning

confidence: 99%

Sodium fast reactor safety and licensing research plan. Volume II.

Ludewig

Powers²,

Hewson³

et al. 2012

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Expert panels comprised of subject matter experts identified at the U.S. National Laboratories (SNL, ANL, INL, ORNL, LBL, and BNL), universities (University of Wisconsin and Ohio State University), international agencies (IRSN, CEA, JAEA, KAERI, and JRC-IE) and private consultation companies (Radiation Effects Consulting) were assembled to perform a gap analysis for sodium fast reactor licensing. Expert-opinion elicitation was performed to qualitatively assess the current state of sodium fast reactor technologies. Five independent gap analyses were performed resulting in the following topical reports: Idaho National Laboratory Robert Bari Brookhaven National Laboratory Robert Budnitz Lawrence Berkeley National Laboratory Jim Cahalan, Chris Grandy, Dave Wade Argonne National Laboratory Michael Corradini University of Wisconsin, Madison Richard Denning Ohio State University George FlanaganOak Ridge National Laboratory Steve Wright Sandia National Laboratories March 2010 FCRD-REAC-2010-0001268 DISCLAIMER This information was prepared as an account of work sponsored by an agency of the U.S. Government. Neither the U.S. Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness, of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. References herein to any specific commercial product, process, or service by trade name, trade mark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the U.S. Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the U.S. Government or any agency thereof. Advanced Sodium Fast Reactor Accident Initiators/Sequences Technology Gap AnalysisMarch 2010 9 SUMMARYAn advanced Sodium-Fast-Reactor (SFR) is being evaluated by DOE to provide the capability to transmute actinides and enhance the long-term fissile fuel-supply for fission reactors. An essential element in this evaluation is whether an adequate technology base exists to support the safety case for an SFR.The panel concluded that there are no major technology gaps in preparing a safety case for an advanced SFR, so long as one stays with known technology. Defining the current state of knowledge was therefore an important activity of the panel, along with the context in which it can be used for licensing. Significant potential departures from known technology were identified, such as development of fuel containing high concentrations of minor actinides, which will require further investments in R&D both to develop the technology and to develop an adequate safety case.

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“…The thermal conductivity was expressed as a piece-wise smooth function where A, B, A 1 , B 1 , λ 1 , λ 2 , and l 2 are constants [14,15]. The thermal power per unit volume of a fuel element was determined as where w and e are constants; q(\ 0 ) = q 0 ; q(R 0 ) = q 1 = 3q 0 .…”

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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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Thermal conductivities of hypostoichiometric (U, Pu, Am)O2−x oxide

Cited by 43 publications

References 25 publications

Physical Properties and Irradiation Behavior Analysis of Np- and Am-Bearing MOX Fuels

Physical Properties and Irradiation Behavior Analysis of Np- and Am-Bearing MOX Fuels

Sodium fast reactor safety and licensing research plan. Volume II.

Numerical modeling of the temperature distribution in a VVER fuel element

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