Manufacture and characteristics of spherical fuel elements for the HTR-10

Zhao, Hongsheng; Liang, Tongxiang; Zhang, Jie; He, Jinliang; Zou, Yanwen; Tang, Chunhe

doi:10.1016/j.nucengdes.2005.10.023

Cited by 42 publications

(26 citation statements)

References 2 publications

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“…The raw graphite matrix powder is composed of natural graphite, synthetic graphite, and resin binder in a certain proportion, which experience a series of high-temperature treatment to form graphite matrix [20]. The binder phenol resin is used to provide adhesion to mixture and helps to adhere the graphite matrix powder to TRISO-coated fuel particles during the overcoating process and will harden into a carbonaceous carbon during the subsequent carbonization process [21].…”

Section: The Current Intensity Effect On Particle Size Of Graphitementioning

confidence: 99%

The Electric Current Effect on Electrochemical Deconsolidation of Spherical Fuel Elements

Chen

Zhao

et al. 2017

Science and Technology of Nuclear Installations

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For High-Temperature Gas-Cooled Reactor in China, fuel particles are bonded into spherical fuel elements by a carbonaceous matrix. For the study of fuel failure mechanism from individual fuel particles, an electrochemical deconsolidation apparatus was developed in this study to separate the particles from the carbonaceous matrix by disintegrating the matrix into fine graphite powder. The deconsolidated graphite powder and free particles were characterized by elemental analysis, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and ceramography. The results showed that the morphology, size distribution, and element content of deconsolidated graphite matrix and free particles were notably affected by electric current intensity. The electrochemical deconsolidation mechanism of spherical fuel element was also discussed.

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Section: The Current Intensity Effect On Particle Size Of Graphitementioning

confidence: 99%

The Electric Current Effect on Electrochemical Deconsolidation of Spherical Fuel Elements

Chen

Zhao

et al. 2017

Science and Technology of Nuclear Installations

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“…G RAPHITE is one of the most important construction materials of the high-temperature gas-cooled reactor (HTR). Due to its excellent properties, such as low thermal expansion coefficient, outstanding thermal shock resistance, and good thermal conductivity, [1][2][3] graphite is used as the matrix material of fuel elements, absorbing elements, discharge tube, and thermal barrier for HTR. Nevertheless, carbon materials are susceptible to oxidise species at above 723 K, which greatly limits its application in severe high-temperature conditions.…”

Section: Introductionmentioning

confidence: 99%

Micro Four‐Layer SiC Coating on Matrix Graphite Spheres of HTR Fuel Elements by Two‐Step Pack Cementation

et al. 2016

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A micro four‐layer SiC coating, which includes inner transition layer, fine‐grained layer, dense bulk layer, and outer loose layer, was fabricated on the matrix graphite spheres of high‐temperature gas‐cooled reactor fuel elements to improve the oxidation‐resistant property by a two‐step pack cementation process. According to the experiment results, the micro four‐layer can be differentiated by SiC grain size and microstructure variation. The oxidation tests at 1773 K for 200 h reveal that the coating structure could effectively improve the oxidation resistance of matrix graphite spheres with a weight gain of 0.52 wt%, and the fine‐grained and dense bulk layers are evidenced as two main antioxidation layers. Although the thermal expansion coefficients of SiC and matrix graphite do not match each other so well, no obvious stress cracking was observed after thermal shocking tests from 1773 K to room temperature for 100 times.

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“…For nuclear application, natural graphite especially flake graphite has been successfully used in HTR spherical fuel elements, the graphite matrix of which is manufactured using a powder mixture composed of 64 wt.% natural flake graphite, 16 wt.% artificial graphite, and 20 wt.% phenol resin binder [12,13]. With such fuel elements the AVR reactor has been successfully operated for 21 years.…”

Section: Introductionmentioning

confidence: 99%

Advantages of natural microcrystalline graphite filler over petroleum coke in isotropic graphite preparation

Shen

Huang

et al. 2015

Carbon

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A B S T R A C TGraphite materials are used in high-temperature gas-cooled reactor (HTR) as moderator and reflector. Nuclear graphite is currently manufactured using coke as the filler; however, improvements in the performance of nuclear graphite are anticipated in order to enhance the safety and lifetime of HTRs. Natural microcrystalline graphite (MG), which is a metamorphic product of coal, is an emerging candidate as filler material. This paper proposes the approach of preparing isotropic graphite using MG fillers. The characterization results of MG ores and purified powder indicate a polycrystalline and near-isotropic structure of MG particles. Thus, near-isotropic graphite with an isotropy ratio of 1.10-1.15 can be easily obtained via cold isostatic pressing. The thermal diffusivity of MG-based green body is much higher than that of coke-based one, therefore facilitates the baking step. The advantages of MG-based graphite also include a high degree of graphitization, and a low coefficient of thermal expansion, both of which are highly beneficial to nuclear applications.As a result, MG exhibits a large potential for the application in isotropic nuclear graphite.Ó 2015 Elsevier Ltd. All rights reserved. IntroductionThe moderator in a nuclear reactor thermalizes 2 MeV fast neutrons to 0.025 eV thermal neutrons. With low atomic weight, high moderating ratio and low absorption cross section, H 2 O, D 2 O, Be, and C are four possible moderators [1]. Carbon in the form of graphite offers an acceptable compromise between nuclear properties and cost, therefore graphite is employed as moderator and structural material in high-temperature gas-cooled reactors (HTR) [2,3].

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Manufacture and characteristics of spherical fuel elements for the HTR-10

Cited by 42 publications

References 2 publications

The Electric Current Effect on Electrochemical Deconsolidation of Spherical Fuel Elements

The Electric Current Effect on Electrochemical Deconsolidation of Spherical Fuel Elements

Micro Four‐Layer SiC Coating on Matrix Graphite Spheres of HTR Fuel Elements by Two‐Step Pack Cementation

Advantages of natural microcrystalline graphite filler over petroleum coke in isotropic graphite preparation

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