WO2020150976A1 - 包覆燃料颗粒、惰性基体弥散燃料芯块和一体化燃料棒及其制造方法 - Google Patents

包覆燃料颗粒、惰性基体弥散燃料芯块和一体化燃料棒及其制造方法 Download PDF

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WO2020150976A1
WO2020150976A1 PCT/CN2019/073029 CN2019073029W WO2020150976A1 WO 2020150976 A1 WO2020150976 A1 WO 2020150976A1 CN 2019073029 W CN2019073029 W CN 2019073029W WO 2020150976 A1 WO2020150976 A1 WO 2020150976A1
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layer
fuel
coated
core
fuel particles
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PCT/CN2019/073029
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English (en)
French (fr)
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刘彤
舒睿
廖业宏
李锐
卢志威
李雷
黄恒
武海龙
马赵丹丹
高思宇
张永栋
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中广核研究院有限公司
广东核电合营有限公司
中国广核集团有限公司
中国广核电力股份有限公司
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Priority to PCT/CN2019/073029 priority Critical patent/WO2020150976A1/zh
Priority to CN201980081090.2A priority patent/CN113196416A/zh
Publication of WO2020150976A1 publication Critical patent/WO2020150976A1/zh

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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
    • G21C3/42—Selection of substances for use as reactor fuel
    • G21C3/58—Solid reactor fuel Pellets made of fissile material
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
    • G21C3/42—Selection of substances for use as reactor fuel
    • G21C3/58—Solid reactor fuel Pellets made of fissile material
    • G21C3/60—Metallic fuel; Intermetallic dispersions
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Definitions

  • the present invention relates to the technical field of nuclear fuel, in particular to a coated fuel particle, an inert matrix dispersed fuel pellet and a manufacturing method thereof, an integrated fuel rod and a manufacturing method thereof.
  • coated fuel particles originated from the United Kingdom and has been used in high-temperature gas-cooled reactor fuel for more than 30 years. my country has established industrial-grade coated fuel particles and graphite spherical fuel element production lines in Tsinghua University and China Nuclear North Nuclear Fuel Element Co., Ltd.
  • the industrially produced coated fuel particles have a spherical UO 2 core inside, and 4 layers of closed spherical shells are wrapped by CVD technology. They are a loose cracked carbon layer, a dense cracked carbon layer, a dense SiC layer, and a dense cracked carbon layer (ie TRISO particles, BISO particles if there are only two layers).
  • the UO 2 coated fuel particles are uniformly dispersed in the graphite matrix and pressed and sintered into spherical fuel elements for application in high-temperature gas-cooled reactors.
  • the four-layer coating shell has excellent containment, protection and shielding effects on the fuel core, so that the fission product fragments and gas of the fuel core are retained in the coating particles. It has been confirmed that no radioactive leakage has been found below 1600°C;
  • the sturdy SiC shell has excellent mechanical properties and physical and chemical stability, so that the coated fuel particles are intact under pressure, high temperature, strong corrosion, and strong irradiation at 100 MPa level, and can withstand harsh application conditions.
  • Coated fuel particles also have significant disadvantages, as follows:
  • the volume fraction of the non-fuel area coated with fuel particles is too large, resulting in low uranium content of fuel elements prepared from coated fuel particles, high manufacturing and use costs, and unable to meet the needs of high power density hydropower plants , Its application is limited to high-temperature gas-cooled reactors, and its market prospects are greatly affected;
  • the fuel core is UO 2 , and the uranium density is low, which will have a negative impact on the uranium loading of the fuel;
  • the UO 2 core has poor thermal conductivity, high core temperature during operation, serious release of fission products, and high internal pressure of coated fuel particles under deep burnup, which severely increases the risk of rupture of the coating shell and radioactive leakage;
  • Spherical graphite fuel elements prepared on the basis of coated fuel particles have the advantages of mature technology and stable material physical properties, but the graphite matrix must be protected by helium during high-temperature operation, and water vapor and oxygen must be strictly removed to prevent chemical reactions. Flammable and toxic gases cause high maintenance costs. In addition, the graphite fuel element cracks due to thermal expansion during the operation, and cannot play a role in shielding radioactivity.
  • the technical problem to be solved by the present invention is to provide a new type of coated fuel particles, an inert matrix dispersed fuel pellet made of the coated fuel particles, and a manufacturing method thereof, and an integrated fuel rod made of the coated fuel particles And its manufacturing method.
  • U x Si y is U 3 Si, U 3 Si 2 or U 3 Si 5 .
  • the diameter of the U x Si y core is 300-1200 ⁇ m.
  • the multi-layer protective shell includes a loose buffer layer, a structural support sealing layer, and a lubricating protective layer sequentially coated on the U x Si y core.
  • the thickness of the loose buffer layer is 20-140 ⁇ m; the thickness of the structural support sealing layer is 20-100 ⁇ m; the thickness of the lubricating protection layer is 30-50 ⁇ m.
  • the thickness of the loose buffer layer is a SiC layer; the structural support sealing layer is a SiC layer with a density greater than that of the loose buffer layer; and the lubricating protection layer is an Al layer.
  • the multilayer protective shell further includes a dense barrier layer disposed between the loose buffer layer and the structural support sealing layer.
  • the thickness of the dense barrier layer is 20-80 ⁇ m.
  • the present invention also provides an inert matrix dispersion fuel pellet, which is characterized in that it is made of any of the above-mentioned coated fuel particles.
  • the present invention also provides a method for manufacturing the above-mentioned inert matrix dispersed fuel pellet, which includes the following steps:
  • step S2 the pressing process includes:
  • the vacuum pressureless sintering densification includes:
  • the inert matrix dispersed fuel pellets are rapidly densified in a second-level process, and the density reaches more than 92%.
  • the present invention also provides an integrated fuel rod, which is characterized in that it is made of any one of the above-mentioned coated fuel particles.
  • the present invention also provides a method for manufacturing the above-mentioned integrated fuel rod, which includes the following steps:
  • the FeCrAl liquid is cooled and solidified to form a FeCrAl matrix and be fixed to the FeCrAl cladding shell, and the coated fuel particles are consolidated in the FeCrAl matrix in a dispersed form to obtain an integrated fuel rod.
  • step S3 the FeCrAl powder is melted by the eddy current of the induction coil.
  • the coated fuel particles of the present invention use U x Si y as the core, which has higher uranium density and higher thermal conductivity than UO 2 and can increase the uranium density of the core material by more than 17% without increasing the degree of enrichment Significantly improve the uranium content of the fuel; the core and the outer protective shell have good chemical compatibility, and will not produce a lot of gas due to chemical reactions at high temperatures. It can be used for accident-tolerant fuel, large-scale advanced pressurized water reactors, and other advanced nuclear energy systems.
  • the coated fuel particles are used in nuclear fuels to improve the thermal conductivity of the fuel and reduce the average temperature of the fuel, thereby alleviating the increase in internal stress caused by thermal expansion and the release of fission gas, and greatly improving the fuel safety performance; the gas inside the coated fuel particles is greatly reduced, The fuel damage rate is reduced and the safety is improved; the inert matrix of the fuel pellets coated with the fuel particles can be cracked, which solves the problem that the FCM cannot use the existing spent fuel processing technology.
  • Fig. 1 is a schematic cross-sectional structure diagram of coated fuel particles according to an embodiment of the present invention
  • FIG. 2 is a schematic diagram of the structure of an inert matrix dispersed fuel pellet according to an embodiment of the present invention
  • FIG. 3 is a schematic cross-sectional structure diagram of an integrated fuel rod according to an embodiment of the present invention.
  • the coated fuel particle 1 of the present invention includes a U x Si y core 10 and a multilayer protective shell 20 covering the U x Si y core 10.
  • U x Si y may be U 3 Si, U 3 Si 2 or U 3 Si 5 .
  • U 3 Si, U 3 Si 2 and U 3 Si 5 are U-Si stable compounds, which all have excellent thermal conductivity. As the temperature increases, the thermal conductivity also increases. At a high temperature of 1500°C, the thermal conductivity of U 3 Si 2 and U 3 Si 5 are 13 times and 7 times that of UO 2 respectively. The thermal conductivity of U 3 Si is more than 13 times that of UO 2 at a phase transition temperature of 900°C. It can be seen that using U x Si y UxSiy as a core can effectively alleviate the safety risks caused by thermal expansion and fission gas release caused by high temperature.
  • the multi-layer protective shell 20 may include a loose buffer layer 21, a dense barrier layer 22, a structural support sealing layer 23, and a lubricating protective layer 24 sequentially coated on the U x Si y core 10.
  • the loose buffer layer 21 is in contact with the U x Si y core 10, which is made of a material with good chemical compatibility with U x Si y , preferably a high melting point compound containing Si, such as SiC SiC layer made.
  • the structural support sealing layer 23 is a provider of key mechanical properties for coating fuel particles and a guarantee for fuel safety.
  • a mature and reliable material such as a SiC layer made of SiC, must be used.
  • the loose buffer layer 21 and the structural support sealing layer 23 made of the same SiC have different functions.
  • the loose buffer layer 21 has a loose structure and its density is less than that of the structural support sealing layer 23, that is, the density of the structural support sealing layer 23 is greater than the loose buffer Layer 21 to play the role of structural support.
  • the lubricating protective layer 24 buffers and protects the coated fuel particles during the process of fuel pellet assembly and pressing.
  • the liquid formed during the sintering process is lubricated against the particles to make it easy to be densified with the matrix material. After the sintering is completed, the liquid disappears without affecting The mechanical properties and radiation properties of the interface between the particles and the matrix.
  • the lubricating protective layer 24 may be an Al layer made of Al.
  • the diameter of the U x Si y core is 300-1200 ⁇ m, preferably 500-800 ⁇ m; the thickness of the loose buffer layer 21 is 20-140 ⁇ m, preferably 50-110 ⁇ m; the thickness of the dense barrier layer 22 is 20-80 ⁇ m, preferably 30
  • the thickness of the structural support sealing layer 23 is 20-100 ⁇ m, preferably 30-60 ⁇ m; the thickness of the lubricating protective layer 24 is 30-50 ⁇ m, preferably 30-50 ⁇ m.
  • the inert matrix dispersed fuel pellet of an embodiment of the present invention is made of the above-mentioned coated fuel particles 1. As shown in FIG. 2, in the inert matrix dispersed fuel pellet, the coated fuel particles 1 are dispersed in the inert matrix 2.
  • the manufacturing method of inert matrix dispersed fuel pellets of the present invention may include the following steps:
  • the green body is densified by vacuum pressureless sintering to obtain an inert matrix dispersion fuel pellet.
  • vacuum pressureless sintering densification includes:
  • the temperature rise rate is 5-20°C/min to 500-800°C, preferably the temperature rise rate is 10°C/min to 500°C;
  • the inert matrix dispersed fuel pellets are rapidly densified in a second-level process, and the density reaches more than 92%.
  • the diameter of the manufactured inert matrix dispersed fuel pellet may be 4-16 mm.
  • the integrated fuel rod of an embodiment of the present invention is made of the above-mentioned coated fuel particles 1.
  • the coated fuel particles 1 are dispersed in the FeCrAl matrix 3.
  • the FeCrAl matrix 3 is located in the FeCrAl cladding 4 and is integrally connected with the inner wall of the FeCrAl cladding 4; the dotted circle in Figure 3 is FeCrAl The connection interface between the substrate 3 and the FeCrAl cladding 4.
  • the manufacturing method of the integrated fuel rod of the present invention may include the following steps:
  • the coated fuel particles 1 and FeCrAl powder are evenly mixed and then dispersedly loaded in the FeCrAl cladding 4.
  • the eddy current generated by the induction coil is used to heat the FeCrAl powder inside the FeCrAl cladding 4 to 1500° C. to melt and immerse all the coated fuel particles 1 to achieve physical connection with the inner wall of the FeCrAl cladding 4. Forced cooling is performed on the outer wall of the FeCrAl cladding 4, and the maximum temperature of the FeCrAl cladding 4 is controlled so as not to undergo annealing that causes performance changes due to eddy current heating.
  • S3 and FeCrAl liquid are cooled and solidified to form a FeCrAl matrix 3 and solidify with the FeCrAl cladding 4, and the coated fuel particles 1 are consolidated in the FeCrAl matrix 3 in a dispersed form to obtain an integrated fuel rod.
  • the diameter of the manufactured integrated fuel rod may be 5-17 mm.
  • the integrated fuel rod is not limited to the matrix and cladding, nor is it limited to FeCrAl materials.
  • the inert matrix and the cladding can be dissolved in nitric acid to realize the recovery of coated fuel particles and the fuel cycle.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
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  • Dispersion Chemistry (AREA)
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  • Monitoring And Testing Of Nuclear Reactors (AREA)

Abstract

一种包覆燃料颗粒、惰性基体弥散燃料芯块和一体化燃料棒及其制造方法，包覆燃料颗粒包括UxSiy核心以及包覆在所述UxSiy核心外的多层保护壳；所述UxSiy核心中，x＝3，y＝1-5。所述包覆燃料颗粒，核心采用UxSiy，较于UO2具有高铀密度及高热导率，可使核芯材料的铀密度提高17％以上，在不增加富集度的情况下明显改善燃料的铀装量；核心与外层的保护壳化学相容性好，在高温下不会因化学反应产生大量气体。可用于事故容错燃料、大型先进压水堆以及其他先进核能系统的燃料系统。

Description

包覆燃料颗粒、惰性基体弥散燃料芯块和一体化燃料棒及其制造方法 技术领域
本发明涉及核燃料技术领域，尤其涉及一种包覆燃料颗粒、惰性基体弥散燃料芯块及其制造方法、一体化燃料棒及其制造方法。
 背景技术
包覆燃料颗粒技术源于英国，在高温气冷堆燃料中有超过30年的成熟应用。我国已在清华大学与中核北方核燃料元件有限公司建立起工业级包覆燃料颗粒与石墨球形燃料元件生产线。
工业化生产的包覆燃料颗粒内有一颗球形的UO 2内核，其外通过CVD技术包裹4层封闭球壳，分别为疏松裂解碳层、致密裂解碳层、致密SiC层、致密裂解碳层（即TRISO颗粒，若只有两层则是BISO颗粒）。将UO 2包覆燃料颗粒均匀弥散在石墨基体中，并压制烧结成球形燃料元件以应用于高温气冷堆。
现有的包覆燃料颗粒具有明显的优点，如下：
1、四层包覆外壳对燃料核芯起到卓越的包容、保护与屏蔽作用，使燃料核芯的裂变产物碎片、气体均滞留于包覆颗粒内，已证实1600℃以下未发现放射性泄漏；
2、坚固的SiC外壳具有优异的力学性能与物理化学稳定性，使包覆燃料颗粒在百兆帕级别压力、高温、强腐蚀、强辐照环境下完好无损，可承受严苛的应用条件。
包覆燃料颗粒也存在显著的缺点，如下：
1、包覆燃料颗粒的非燃料区所占体积分数过大，导致由包覆燃料颗粒制备的燃料元件铀装量较低，制造、使用成本较高，无法满足功率密度高的水堆电站需求，其应用局限在高温气冷堆，市场前景大受影响；
2、燃料核芯为UO 2，铀密度较低，对燃料的铀装量造成负面影响；
3、UO 2核芯导热能力差，运行时核芯温度高，裂变产物释放严重，深燃耗下包覆燃料颗粒内压很大，严重加剧包覆外壳的破裂与放射性泄露风险；
4、UO 2核芯与毗邻的疏松裂解碳外壳在约1500℃时因剧烈碳热反应生成大量CO气体，极大增加包覆燃料颗粒内压直至引发包覆外壳破裂与放射性泄露。
以包覆燃料颗粒为基础制备的球型石墨燃料元件具有工艺成熟、材料物理性能稳定等优点，但是石墨基体在高温运行中必须用氦气作为保护，严格去除水蒸汽与氧气以防止化学反应产生可燃、有毒气体，导致使用维护成本高昂。且石墨燃料元件运行过程中因热膨胀发生开裂，无法起到屏蔽放射性的作用。
 技术问题
本发明要解决的技术问题在于，提供一种新型的包覆燃料颗粒、该包覆燃料颗粒制成的惰性基体弥散燃料芯块及其制造方法、该包覆燃料颗粒制成的一体化燃料棒及其制造方法。
 技术解决方案
本发明解决其技术问题所采用的技术方案是：提供一种包覆燃料颗粒，包括U xSi y核心以及包覆在所述U xSi y核心外的多层保护壳；所述U xSi y核心中，x=3，y=1-5。
优选地，所述U xSi y核心中，U xSi y为U 3Si、U 3Si 2或U 3Si 5。
优选地，所述U xSi y核心的直径为300-1200μm。
优选地，所述多层保护壳包括依次包覆在所述U xSi y核心上的疏松缓冲层、结构支撑密封层以及润滑保护层。
优选地，所述疏松缓冲层的厚度为20-140μm；所述结构支撑密封层的厚度为20-100μm；所述润滑保护层的厚度为30-50μm。
优选地，所述疏松缓冲层的厚度为SiC层；所述结构支撑密封层为SiC层，且密度大于所述疏松缓冲层；所述润滑保护层为Al层。
优选地，所述多层保护壳还包括设置在所述疏松缓冲层和结构支撑密封层之间的致密阻挡层。
优选地，所述致密阻挡层的厚度为20-80μm。
优选地，所述致密阻挡层为ZrC x层或裂解C层；所述ZrC x层中，x=0.5-0.8。
本发明还提供一种惰性基体弥散燃料芯块，其特征在于，采用上述任一项所述的包覆燃料颗粒制成。
本发明还提供上述的惰性基体弥散燃料芯块的制造方法，包括以下步骤：
S1、取5-20wt.%的惰性基体粉末均匀混合溶剂中形成浆料，并将浆料喷洒在滚动的包覆燃料颗粒表面，浆料烘干后形成粘附在包覆燃料颗粒表面的包覆层；
S2、将剩余的惰性基体粉末与带有包覆层的包覆燃料颗粒按比例混合后，放入芯块模具中压制形成坯体；
S3、将所述坯体进行真空无压烧结致密化，制得惰性基体弥散燃料芯块。
优选地，步骤S2中，压制过程包括：
施加5-10MPa的压力进行预压后用油纸真空密封；
使用冷等静压机对油纸真空密封的坯体施加100-300MPa的等压载荷并保压1-5分钟，使坯体初始密度达到50%以上。
优选地，步骤S3中，真空无压烧结致密化包括：
以升温速率为5-20°C/min升温至500-800℃；
施加电压80-150V，脉冲电流3000A-5000A，在秒级过程中使惰性基体弥散燃料芯块快速致密化，致密度达到92% 以上。
本发明还提供一种一体化燃料棒，其特征在于，采用上述任一项所述的包覆燃料颗粒制成。
本发明还提供上述一体化燃料棒的制造方法，包括以下步骤：
S1、将包覆燃料颗粒与FeCrAl粉末混合均匀后弥散装载于FeCrAl包壳中；
S2、加热使FeCrAl粉末融化形成FeCrAl液体；
S3、FeCrAl液体冷却凝固后形成FeCrAl基体并与FeCrAl包壳固接，所述包覆燃料颗粒以分散形式固结在FeCrAl基体中，制得一体化燃料棒。
优选地，步骤S3中，通过感应线圈的涡流融化FeCrAl粉末。
 有益效果
本发明的包覆燃料颗粒，核心采用U xSi y，较于UO 2具有高铀密度及高热导率，可使核芯材料的铀密度提高17%以上，在不增加富集度的情况下明显改善燃料的铀装量；核心与外层的保护壳化学相容性好，在高温下不会因化学反应产生大量气体。可用于事故容错燃料、大型先进压水堆以及其他先进核能系统的燃料系统。
该包覆燃料颗粒应用于核燃料中，提高燃料热导率，降低燃料平均温度，从而缓解热膨胀与裂变气体释放导致的内应力增加，大幅提高燃料安全性能；包覆燃料颗粒内部气体的大幅减少，降低燃料破损率，提高安全性；用该包覆燃料颗粒的燃料芯块的惰性基体可裂解，解决了FCM无法使用现有乏燃料处理技术的问题。
 附图说明
下面将结合附图及实施例对本发明作进一步说明，附图中：
图1是本发明一实施例的包覆燃料颗粒的剖面结构示意图；
图2是本发明一实施例的惰性基体弥散燃料芯块的结构示意图；
图3是本发明一实施例的一体化燃料棒的剖面结构示意图。
 本发明的实施方式
为了对本发明的技术特征、目的和效果有更加清楚的理解，现对照附图详细说明本发明的具体实施方式。
如图1所示，本发明的包覆燃料颗粒1，包括U xSi y核心10以及包覆在U xSi y核心10外的多层保护壳20。
在U xSi y核心10的U xSi y中，x=3，y=1-5；y可以取1-5中任意数。作为选择，U xSi y可以为U 3Si、U 3Si 2或U 3Si 5。U 3Si、U 3Si 2和U 3Si 5为U-Si稳定化合物，均具有优异的导热性能，随着温度的升高，其热导率也升高。在1500℃高温下，U 3Si 2与U 3Si 5的热导率分别是UO 2的13倍与7倍。U 3Si在相变温度900℃时热导率是UO 2的13倍以上。可见，使用U xSi yUxSiy作为核芯可有效缓解高温造成的热膨胀、裂变气体释放带来的安全风险。
另外，在极深燃耗下，U 3Si、U 3Si 2和U 3Si 5，特别是U 3Si 2具有明显优异的抗辐照肿胀性能。
多层保护壳20可包括依次包覆在U xSi y核心10上的疏松缓冲层21、致密阻挡层22、结构支撑密封层23以及润滑保护层24。
在多层保护壳20中，疏松缓冲层21与U xSi y核心10相接触，其由与U xSi y化学相容性佳的材料制成，以含Si高熔点化合物为宜，如SiC制成的SiC层。
致密阻挡层22可根据情况设置或取消，其采用抗辐照性能极高且结构致密的材料制成，例如为ZrC x层或裂解C层，其中ZrC x为非标准化学计量单相纯净物，x= x=0.5-0.8，C缺位型ZrC x具有优异的耐辐照性能，在高能量重离子大剂量辐照后，其X射线衍射图像未发现新的衍射峰（出现新相）或者出现峰宽化（非晶化）。
结构支撑密封层23是包覆燃料颗粒的关键力学性能提供者，是燃料安全的保障，必须使用成熟可靠的材料，如为SiC制成的SiC层。对于相同SiC制成的疏松缓冲层21和结构支撑密封层23，两者作用不同，疏松缓冲层21具有疏松结构，其密度小于结构支撑密封层23，即结构支撑密封层23的密度大于疏松缓冲层21，以起到结构支撑的作用。
润滑保护层24在燃料芯块组装、压制过程中对包覆燃料颗粒进行缓冲保护，在烧结过程中形成液相对颗粒进行润滑使之易于随基体材料致密化，烧结完成后液相应消失且不影响颗粒与基体界面的力学性能与辐照性能。润滑保护层24可以是Al制成的Al层。
在尺寸方面，U xSi y核心的直径为300-1200μm，优选500-800μm；疏松缓冲层21的厚度为20-140μm，优选50-110μm；致密阻挡层22的厚度为20-80μm，优选30-60μm；结构支撑密封层23的厚度为20-100μm，优选30-60μm；润滑保护层24的厚度为30-50μm，优选30-50μm。
本发明一实施例的惰性基体弥散燃料芯块，采用上述的包覆燃料颗粒1制成。如图2所示，在惰性基体弥散燃料芯块中，包覆燃料颗粒1分散在惰性基体2中。
参考图2，本发明的惰性基体弥散燃料芯块的制造方法，可包括以下步骤：
S1、取5-20wt.%的惰性基体粉末均匀混合溶剂（如乙醇）中形成浆料，并将浆料喷洒在滚动的包覆燃料颗粒1表面，浆料烘干后形成粘附在包覆燃料颗粒1表面的包覆层。
S2、将剩余的惰性基体粉末与带有包覆层的包覆燃料颗粒1按比例混合后，放入芯块模具中压制形成坯体。
压制时，先施加5-10MPa的压力进行预压后用油纸真空密封；再使用冷等静压机对油纸真空密封的坯体施加100-300MPa的等压载荷并保压1-5分钟，使坯体初始密度达到50%以上。
S3、将坯体进行真空无压烧结致密化，制得惰性基体弥散燃料芯块。
其中，真空无压烧结致密化包括：
以升温速率为5-20°C/min升温至500-800℃，可优选以升温速率为10°C/min升温至500℃；
施加电压80-150V，脉冲电流3000A-5000A，在秒级过程中使惰性基体弥散燃料芯块快速致密化，致密度达到92% 以上。
在一种优选实施方式中，制成的惰性基体弥散燃料芯块的直径可为4-16mm。
本发明一实施例的一体化燃料棒，采用上述的包覆燃料颗粒1制成。如图3所示，在一体化燃料棒中，包覆燃料颗粒1分散在FeCrAl基体3中，FeCrAl基体3位于FeCrAl包壳4内并与FeCrAl包壳4内壁一体连接；图3虚线圆圈为FeCrAl基体3和FeCrAl包壳4的连接界面。
参考图3，本发明的一体化燃料棒的制造方法，可包括以下步骤：
S1、将包覆燃料颗粒1与FeCrAl粉末混合均匀后弥散装载于FeCrAl包壳4中。
S2、加热使FeCrAl粉末融化形成FeCrAl液体。
使用感应线圈产生的涡流加热FeCrAl包壳4内部的FeCrAl粉末至1500℃，使之融化并浸没全部包覆燃料颗粒1，实现与FeCrAl包壳4内壁物理连接。对FeCrAl包壳4外壁实施强制冷却，控制FeCrAl包壳4最高温度，使其不因涡流加热而发生导致性能变化的退火。
S3、FeCrAl液体冷却凝固后形成FeCrAl基体3并与FeCrAl包壳4固接，包覆燃料颗粒1以分散形式固结在FeCrAl基体3中，制得一体化燃料棒。
在一种优选实施方式中，制成的一体化燃料棒的直径可为5-17mm。
一体化燃料棒中也不限于基体和包壳也不限于FeCrAl材料制成。
本发明的惰性基体弥散燃料芯块和一体化燃料棒中，惰性基体和包壳可在硝酸中溶解，实现包覆燃料颗粒的回收与燃料循环。
以上所述仅为本发明的实施例，并非因此限制本发明的专利范围，凡是利用本发明说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其他相关的技术领域，均同理包括在本发明的专利保护范围内。

Claims (16)

  1. 一种包覆燃料颗粒，其特征在于，包括U xSi y核心以及包覆在所述U xSi y核心外的多层保护壳；所述U xSi y核心中，x=3，y=1-5。
  2. 根据权利要求1所述的包覆燃料颗粒，其特征在于，所述U xSi y核心中，U xSi y为U 3Si、U 3Si 2或U 3Si 5。
  3. 根据权利要求1所述的包覆燃料颗粒，其特征在于，所述U xSi y核心的直径为300-1200μm。
  4. 根据权利要求1所述的包覆燃料颗粒，其特征在于，所述多层保护壳包括依次包覆在所述U xSi y核心上的疏松缓冲层、结构支撑密封层以及润滑保护层。
  5. 根据权利要求4所述的包覆燃料颗粒，其特征在于，所述疏松缓冲层的厚度为20-140μm；所述结构支撑密封层的厚度为20-100μm；所述润滑保护层的厚度为30-50μm。
  6. 根据权利要求4所述的包覆燃料颗粒，其特征在于，所述疏松缓冲层的厚度为SiC层；所述结构支撑密封层为SiC层，且密度大于所述疏松缓冲层；所述润滑保护层为Al层。
  7. 根据权利要求4所述的包覆燃料颗粒，其特征在于，所述多层保护壳还包括设置在所述疏松缓冲层和结构支撑密封层之间的致密阻挡层。
  8. 根据权利要求7所述的包覆燃料颗粒，其特征在于，所述致密阻挡层的厚度为20-80μm。
  9. 根据权利要求7所述的包覆燃料颗粒，其特征在于，所述致密阻挡层为ZrC x层或裂解C层；所述ZrC x层中，x=0.5-0.8。
  10. 一种惰性基体弥散燃料芯块，其特征在于，采用权利要求1-9任一项所述的包覆燃料颗粒制成。
  11. 一种权利要求10所述的惰性基体弥散燃料芯块的制造方法，其特征在于，包括以下步骤：
    S1、取5-20wt.%的惰性基体粉末均匀混合溶剂中形成浆料，并将浆料喷洒在滚动的包覆燃料颗粒表面，浆料烘干后形成粘附在包覆燃料颗粒表面的包覆层；
    S2、将剩余的惰性基体粉末与带有包覆层的包覆燃料颗粒按比例混合后，放入芯块模具中压制形成坯体；
    S3、将所述坯体进行真空无压烧结致密化，制得惰性基体弥散燃料芯块。
  12. 根据权利要求11所述的制造方法，其特征在于，步骤S2中，压制过程包括：
    施加5-10MPa的压力进行预压后用油纸真空密封；
    使用冷等静压机对油纸真空密封的坯体施加100-300MPa的等压载荷并保压1-5分钟，使坯体初始密度达到50%以上。
  13. 根据权利要求11所述的制造方法，其特征在于，步骤S3中，真空无压烧结致密化包括：
    以升温速率为5-20°C/min升温至500-800℃；
    施加电压80-150V，脉冲电流3000A-5000A，在秒级过程中使惰性基体弥散燃料芯块快速致密化，致密度达到92% 以上。
  14. 一种一体化燃料棒，其特征在于，采用权利要求1-9任一项所述的包覆燃料颗粒制成。
  15. 一种权利要求14所述的一体化燃料棒的制造方法，其特征在于，包括以下步骤：
    S1、将包覆燃料颗粒与FeCrAl粉末混合均匀后弥散装载于FeCrAl包壳中；
    S2、加热使FeCrAl粉末融化形成FeCrAl液体；
    S3、FeCrAl液体冷却凝固后形成FeCrAl基体并与FeCrAl包壳固接，所述包覆燃料颗粒以分散形式固结在FeCrAl基体中，制得一体化燃料棒。
  16. 根据权利要求15所述的制造方法，其特征在于，步骤S3中，通过感应线圈的涡流融化FeCrAl粉末。
PCT/CN2019/073029 2019-01-24 2019-01-24 包覆燃料颗粒、惰性基体弥散燃料芯块和一体化燃料棒及其制造方法 WO2020150976A1 (zh)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012129677A1 (en) * 2011-03-28 2012-10-04 Torxx Group Inc. Ceramic encapsulations for nuclear materials and systems and methods of production and use
CN105225702A (zh) * 2015-09-23 2016-01-06 中科华核电技术研究院有限公司 高安全性燃料棒及其制造方法
CN105405474A (zh) * 2015-11-02 2016-03-16 西北工业大学 具备抗裂纹扩展能力的核燃料包壳管的结构及制备方法
US20170040069A1 (en) * 2011-08-04 2017-02-09 Francesco Venneri Dispersion Ceramic Micro-encapsulated (DCM) Nuclear Fuel and Related Methods
CN107180654A (zh) * 2017-05-27 2017-09-19 中国工程物理研究院材料研究所 一种max相陶瓷基体弥散芯块核燃料及其制法和用途

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10109381B2 (en) * 2015-06-22 2018-10-23 Battelle Energy Alliance, Llc Methods of forming triuranium disilicide structures, and related fuel rods for light water reactors
CN106981318B (zh) * 2017-04-13 2019-03-08 中国工程物理研究院材料研究所 一种惰性基弥散芯块燃料及其制备方法和用途

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012129677A1 (en) * 2011-03-28 2012-10-04 Torxx Group Inc. Ceramic encapsulations for nuclear materials and systems and methods of production and use
US20170040069A1 (en) * 2011-08-04 2017-02-09 Francesco Venneri Dispersion Ceramic Micro-encapsulated (DCM) Nuclear Fuel and Related Methods
CN105225702A (zh) * 2015-09-23 2016-01-06 中科华核电技术研究院有限公司 高安全性燃料棒及其制造方法
CN105405474A (zh) * 2015-11-02 2016-03-16 西北工业大学 具备抗裂纹扩展能力的核燃料包壳管的结构及制备方法
CN107180654A (zh) * 2017-05-27 2017-09-19 中国工程物理研究院材料研究所 一种max相陶瓷基体弥散芯块核燃料及其制法和用途

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
LIU, JUNKAI ET AL.: "A Complete Review and a Prospect on the Candidate Materials for Accident-tolerant Fuel Claddings", MATERIALS REVIEW A: REVIEW PAPERS, vol. 32, no. 6, 30 June 2018 (2018-06-30), ISSN: 1005-023X, DOI: 20191009100240Y *

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