Preparation method of beryllium oxide modified uranium dioxide nuclear fuel

A technology of uranium dioxide and beryllium oxide, which is used in reactor fuel elements, reactor fuel materials, nuclear engineering, etc., can solve the problem of high centerline temperature and cross-section temperature gradient of fuel pellets, increased thermal stress, and low thermal conductivity. problems, achieving good high temperature and radiation stability, improving thermal conductivity, and simple preparation methods.

Active Publication Date: 2017-09-29
MATERIAL INST OF CHINA ACADEMY OF ENG PHYSICS +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But UO 2 The thermal conductivity of the UO is very low, and the heat is transferred through phonons, and its thermal conductivity will drop sharply in the high-temperature irradiation environment, which directly leads to the UO 2 The fuel pellet centerline temperature and cross-sectional temperature gradient are both high
This phenomenon directly leads

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0018] The purpose of this example is to provide a preparation method of beryllium oxide improved uranium dioxide nuclear fuel, which adopts spheroidization and coating technology to make BeO micropowder very uniformly coated on UO 2 On the particle surface, BeO will be very uniformly dispersed in UO after forming 2 In the matrix, after a long time of high-temperature sintering, BeO in UO 2 Particle gaps are locally melted and connected to each other to form a three-dimensional network structure, and finally BeO is evenly distributed, and it is compatible with UO 2 BeO modified UO with matrix forming interpenetrating network structure 2 In nuclear fuel, the BeO enhanced phase of the three-dimensional network structure provides a fast channel for heat conduction, making BeO / UO 2 The thermal conductivity of the composite pellets is maximized, and the UO of the three-dimensional network structure 2 The matrix is ​​interwoven with BeO, which can well support and constrain the B...

example 1

[0020] (1) mixing uranium dioxide powder with a particle diameter of 100nm and zinc stearate in a ratio of 1:0.003 by mass, and obtaining uranium dioxide mixture powder after mixing for 24 hours;

[0021] (2) Put the uranium dioxide mixture powder into the powder metallurgy pre-pressing mold, and press it to a density of 5.2g / cm 3 The uranium dioxide pre-press is crushed and sieved to obtain uranium dioxide particles with a particle size of 30 mesh, and then the uranium dioxide particles are put into the spheroidization equipment for grinding and spheroidization6 Hours, obtain uranium dioxide pellets with good sphericity;

[0022] (3) Put uranium dioxide pellets into the mixing and coating equipment, add beryllium oxide powder with a volume ratio of 0.08:1 and a particle size of 10 μm to uranium dioxide and mix and coat for 1 hour to obtain beryllium oxide in The surface of uranium pellets is coated with uniform uranium dioxide / beryllium oxide core-shell particles;

[0023] ...

example 2

[0026] (1) mixing uranium dioxide powder with a particle diameter of 50nm and zinc stearate in a mass ratio of 1:0.001, and mixing for 12 hours to obtain uranium dioxide mixture powder;

[0027] (2) Put the uranium dioxide mixture powder into the powder metallurgy pre-pressing mold, and press it to a density of 6.2g / cm 3 The uranium dioxide pre-press is crushed and sieved to obtain uranium dioxide particles with a particle size of 100 mesh, and then the uranium dioxide particles are put into the spheroidization equipment for grinding and spheroidization12 Hours, obtain uranium dioxide pellets with good sphericity;

[0028] (3) Put uranium dioxide pellets into the mixed coating equipment, add beryllium oxide powder with a volume ratio of 0.15:1 and a particle size of 20 μm to uranium dioxide and mix and coat for 4 hours to obtain beryllium oxide in The surface of uranium pellets is coated with uniform uranium dioxide / beryllium oxide core-shell particles;

[0029] (4) Put the ...

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Abstract

The invention discloses a preparation method of a beryllium oxide modified uranium dioxide nuclear fuel. The preparation method comprises the following steps: extremely uniformly coating the surfaces of UO2 particles with BeO micro-powder through a spheroidizing and cladding technology, shaping the coated UO2 particles to make BeO extremely uniformly dispersed in a UO2 matrix, and carrying out high temperature sintering for a long time to locally melt the BeO in UO2 particle gaps and realize intercommunication in order to form a three-dimensional network structure and finally obtain the BeO modified UO2 nuclear fuel containing uniform distributed BeO and having a BeO and UO2 matrix formed interpenetrating network structure. The BeO enhancement phase of the three-dimensional network structure provides a rapid channel for heat conduction, so the heat conductivity of a BeO/UO2 composite core is maximally improved; and the UO2 matrix and the BeO of the three-dimensional network structure are interlaced, and can well support and constrain the BeO enhancement phase in a high temperature radiation environment, so the high temperature stability and the radiation resistance of the core are well guaranteed.

Description

technical field [0001] The invention relates to the field of nuclear fuel, in particular to a preparation method of beryllium oxide improved uranium dioxide nuclear fuel. Background technique [0002] Uranium dioxide (UO 2 ) has the advantages of high melting point, strong fission gas holding capacity, and good radiation stability, and is currently the preferred nuclear fuel material for nuclear power plants. But UO 2 The thermal conductivity of the UO is very low, and the heat is transferred through phonons, and its thermal conductivity will drop sharply in the high-temperature irradiation environment, which directly leads to the UO 2 The centerline temperature and cross-sectional temperature gradient of the fuel pellets are both high. This phenomenon directly leads to a significant increase in the thermal stress of the interaction between the fuel pellet and the cladding tube at high temperature, cracking, displacement, and creep of the pellet, and also intensifies the ...

Claims

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Application Information

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IPC IPC(8): G21C3/62
CPCG21C3/623Y02E30/30
Inventor 杨振亮刘彤李冰清黄华伟高瑞孙茂州贾建平马赵丹丹
Owner MATERIAL INST OF CHINA ACADEMY OF ENG PHYSICS
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