Preparation method of monocrystalline high-heat-conductivity uranium dioxide nuclear fuel core block

A uranium dioxide and nuclear fuel technology, applied in the fields of reactor fuel material, nuclear engineering, nuclear power generation, etc., can solve the problems of increasing the cladding temperature, cracking of the zirconium alloy cladding layer, low thermal conductivity, etc. The effect of improving anti-radiation performance, improving thermal conductivity performance, and improving economic benefits

Inactive Publication Date: 2019-04-23
MATERIAL INST OF CHINA ACADEMY OF ENG PHYSICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But UO 2 There is still a significant problem of low thermal conductivity, which is only 2.8 W/m K at 1000 °C, which leads to UO 2 There is a large temperature gradient in the fuel pellets, resulting in high core temperature and severe thermal stress, which will lead to large-scale cracking of the fuel pellets, and these cracks will significantly increase the release of fission gases under high burnup conditions, The increase of the operating temperature of the reactor will further accelerate the release of fission gas and form bubbles, which will cause the swelling of the fuel pellets. Therefore, the UO in the reactor 2 Fuel life is significantly limited
[0003] In addition, the h

Method used

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  • Preparation method of monocrystalline high-heat-conductivity uranium dioxide nuclear fuel core block
  • Preparation method of monocrystalline high-heat-conductivity uranium dioxide nuclear fuel core block
  • Preparation method of monocrystalline high-heat-conductivity uranium dioxide nuclear fuel core block

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example 1

[0047] UO with a particle size of 110nm 2 The powder and 0.1wt.% Akewax are loaded into SPS low-temperature calcining special graphite molds, and then placed in SPS sintering furnace for low-temperature rapid pre-sintering to obtain a density of 5.5g / cm 3 UO 2 Preform. Will UO 2 The preform is crushed and sieved to obtain UO with a particle size of 15 mesh 2 particles, then the UO 2 Put the particles into the spheroidization equipment for grinding and spheroidization for 4 hours to obtain UO with good sphericity 2 small ball. Will UO 2 Put the pellets into the mixed coating equipment, add 15vol.% single crystal growth aid Cr with a particle size of 20μm 2 o 3 , mixed and coated for 1 hour to obtain UO 2 @Cr 2 o 3 single-layer core-shell particles. Put the single-layer core-shell structure particles into the mixing and coating equipment, add 20vol.% of the thermal conductivity enhancing phase BeO with a particle size of 50nm, and mix and coat for 1 hour to obtain UO...

example 2

[0050] UO with a particle size of 50 μm 2 The powder and 0.5wt.% Akewax are loaded into the powder metallurgy preforming mold and carry out biaxial compression molding to obtain a density of 6.0g / cm 3 UO 2 Preform. Will UO 2 The preform is crushed and sieved to obtain UO with a particle size of 80 mesh 2 particles, then the UO 2 Put the particles into the spheroidization equipment for grinding and spheroidization for 10 hours to obtain UO with good sphericity 2 small ball. Will UO 2 Put the pellets into the mixed coating equipment, add 5vol.% single crystal growth aid Al with a particle size of 20nm 2 o 3 \Y 2 o 3 , where Al 2 o 3 and Y 2 o 3 The mass ratio is 1:1, mixed and coated for 0.5 hours to obtain UO 2 @Al 2 o 3 \Y 2 o 3 single-layer core-shell particles. Put the single-layer core-shell particles into the mixing and coating equipment, add 25vol.% of the thermal conductivity enhancing phase Graphene with a particle size of 1 μm, and mix and coat for ...

example 3

[0053] UO with a particle size of 200 μm 2 The powder and 0.05% zinc stearate are loaded into SPS low-temperature calcining special graphite molds, and then placed in SPS sintering furnace for low-temperature rapid pre-sintering to obtain a density of 6.3g / cm 3 UO 2 Preform. Will UO 2 The preform is crushed and sieved to obtain UO with a particle size of 80 mesh 2 particles, then the UO 2 Put the particles into the spheroidization equipment for grinding and spheroidization for 8 hours to obtain UO with good sphericity 2 small ball. Will UO 2 Put the pellets into the mixing and coating equipment, add 8vol.% single crystal growth aid Cr with a particle size of 20nm to 100μm 2 o 3 , mixed and coated for 1 hour to obtain UO 2 @Cr 2 o 3 single-layer core-shell particles. Put the single-layer core-shell structure particles into the mixing and coating equipment, add 30vol.% of the thermal conductivity enhancing phase Mo with a particle size of 20nm, and mix and coat for 6...

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Abstract

The invention discloses a preparation method of a monocrystal high-heat-conductivity uranium dioxide nuclear fuel core block. The preparation method comprises the following steps: mixing and wrappinga monocrystal growth aid and a heat conductivity enhancing phase with UO2 particles, carrying out the high-temperature sintering in an active atmosphere, liquedifying the monocrystal growth aid, mutually diffusing the liquefied monocrystal growth aid and UO2 to form UO2 monocrystals, continuously distributing the heat conductivity enhancing phase on the periphery of each monocrystal UO2 particle,and forming the monocrystal high-heat-conductivity UO2 fuel core block with an inter-penetrating network structure with the monocrystal UO2 particles. The heat conductivity of the fuel core block is greatly improved, so that the operation safety of a reactor can be apparently improved, and the economic benefit of a nuclear station can be increased.

Description

technical field [0001] The invention relates to the preparation of nuclear fuel elements, in particular to a method for preparing single crystal high thermal conductivity uranium dioxide nuclear fuel pellets. Background technique [0002] Uranium dioxide (UO 2 ) is currently the most commonly used nuclear fuel for commercial nuclear reactors. It has high melting point, good high temperature stability, good chemical compatibility with cladding materials and coolants, strong radiation resistance, and thermal neutron capture of oxygen as a non-fission combination element Significant advantages such as low cross-section. But UO 2 There is still a significant problem of low thermal conductivity, which is only 2.8 W / m K at 1000 °C, which leads to UO 2 There is a large temperature gradient in the fuel pellets, resulting in high core temperature and severe thermal stress, which will lead to large-scale cracking of the fuel pellets, and these cracks will significantly increase the...

Claims

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Application Information

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IPC IPC(8): G21C21/02G21C3/42G21C3/58
CPCG21C3/42G21C3/58G21C21/02Y02E30/30
Inventor 杨振亮李冰清高瑞褚明福张鹏程刘徐徐钟毅段丽美黄奇奇王志毅程亮刘朋闯严彪杰王昀
Owner MATERIAL INST OF CHINA ACADEMY OF ENG PHYSICS
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