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A zrc and uo 2 Composite fuel pellets and its preparation method and application

A composite fuel, UO2 technology, applied in the manufacture of reactors, reactor fuel materials, reactor fuel elements, etc., can solve the problems of low safety performance and low thermal conductivity of fuel assemblies, achieve simple operation, simple preparation method, and improve UO2 heat. The effect of conductivity

Active Publication Date: 2020-05-01
MATERIAL INST OF CHINA ACADEMY OF ENG PHYSICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem that the present invention solves is: provide a kind of ZrC and UO 2 Composite fuel pellets to solve UO in the prior art 2 Low safety performance of fuel assemblies due to low thermal conductivity

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Step 1, mix and match raw materials as follows:

[0028] UO 2 , 5~8μm, 235 U enrichment 1~5%, 99vol%; ZrC, particle size 30-40μm, 1vol%; Acrawax, UO 2 and 0.05vol.% of the total amount of ZrC. Put the above powder in a nylon ball mill jar, add 1-2 times the mass of alcohol and 3 times the mass of zirconia grinding balls, wet mix for 24 hours, and then dry at 70-100°C for 24 hours.

[0029] Step 2, carry out sintering as follows:

[0030] The mixed powder is molded to obtain the fuel pellet blank, and the molding pressure is 400Mpa

[0031] The green body is placed in an atmosphere sintering furnace for pressureless sintering. First, heat up to about 600°C at a rate of 5-10°C / min and keep it warm for 0.5h, then perform degreasing treatment, vacuum degree 10 -2 ~10 Pa. Raise the temperature to 1650°C at a rate of 1°C / min, hold the temperature for 1h, cool the furnace, protect the atmosphere with hydrogen, and the pressure is 10-50kPa.

[0032] Step 3: Take out the...

Embodiment 2

[0034] Step 1, mix and match raw materials as follows:

[0035] UO 2 , 30-40μm, 235 U enrichment 1~5%, 99vol%; ZrC, particle size 200nm, 1vol%; Acrawax, UO 2 and 0.05vol.% of the total amount of ZrC. Put the above powder in a nylon ball mill jar, add 1-2 times the mass of alcohol and 3 times the mass of zirconia grinding balls, wet mix for 24 hours, and then dry at 70-100°C for 24 hours.

[0036] Step 2, carry out sintering as follows:

[0037] The mixed powder is molded to obtain the fuel pellet blank, and the molding pressure is 300Mpa

[0038] The green body is placed in an atmosphere sintering furnace for pressureless sintering. First, heat up to about 600°C at a rate of 5-10°C / min and keep it warm for 0.5h, then perform degreasing treatment, vacuum degree 10 -2 ~10 Pa. Raise the temperature to 1650°C at a rate of 1°C / min, hold the temperature for 1h, cool the furnace, protect the atmosphere with hydrogen, and the pressure is 10-50kPa.

[0039] Step 3: Take out the...

Embodiment 3

[0041] Step 1, mix and match raw materials as follows:

[0042] UO 2 , 30-40μm, 235 U enrichment 1~5%, 99vol%; ZrC, particle size 40μm, 1vol%; Acrawax, UO 2 and 0.05vol.% of the total amount of ZrC. Put the above powder in a nylon ball mill jar, add 1-2 times the mass of alcohol and 3 times the mass of zirconia grinding balls, wet mix for 24 hours, and then dry at 70-100°C for 24 hours.

[0043] Step 2, carry out sintering as follows:

[0044] The mixed powder is molded to obtain the fuel pellet blank, and the molding pressure is 200Mpa

[0045] The green body is placed in an atmosphere sintering furnace for pressureless sintering. First, heat up to about 600°C at a rate of 5-10°C / min and keep it warm for 0.5h, then perform degreasing treatment, vacuum degree 10 -2 ~10 Pa. Raise the temperature to 1650°C at a rate of 1°C / min, hold the temperature for 1h, cool the furnace, protect the atmosphere with hydrogen, and the pressure is 10-50kPa.

[0046] Step 3: Take out the sa...

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Abstract

The invention discloses a ZrC and UO2 composite fuel pellet as well as a preparation method and application of the ZrC and UO2 composite fuel pellet and aims at solving the problem that UO2 is super-low in heat conductivity to result in relatively low safety performance of a fuel assembly in the prior art. The ZrC and UO2 composite fuel pellet disclosed by the invention is prepared by sintering raw materials including UO2 and ZrC at high temperature, wherein the enrichment degree of 235U in UO2 is 1%-5%, and the dosage of ZrC does not exceed 10vol% of total quantity of UO2 and ZrC. The preparation method disclosed by the invention comprises the steps: uniformly mixing UO2, ZrC and a lubricant according to a certain proportion, carrying out high-temperature sintering, carrying out furnace cooling, then, taking out a sample, and processing the sample to the required shape and size. By using the ZrC and UO2 composite fuel pellet disclosed by the invention, the heat conductivity of UO2 canbe effectively increased, so that the safety performance of the fuel assembly is improved. The preparation method disclosed by the invention is simple and convenient to operate.

Description

technical field [0001] The invention belongs to the technical field of nuclear fuel, in particular to a kind of ZrC and UO 2 Composite fuel pellets and their preparation and application. Background technique [0002] Uranium dioxide (UO 2 ) is currently the most widely used nuclear fuel in commercial nuclear reactors. It has excellent thermal, chemical, and radiation stability, as well as high melting point, retention of solid fission products, and strong ability to block the diffusion of gaseous fission products. However, relying on the characteristics of phonon heat transfer causes its thermal conductivity to drop sharply under high temperature and irradiation conditions, and its heat export ability declines rapidly. Therefore, the current UO 2 The operating temperature of the -Zr nuclear fuel system is only 700-1200°C. In an accident state, the cooling system of the reactor fails, the heat in the reactor cannot be dissipated, the temperature of the core rises rapidly,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G21C3/62G21C21/16
CPCG21C3/623G21C21/16Y02E30/30
Inventor 高瑞杨振亮李冰清张鹏程褚明福钟毅刘徐徐段丽美黄奇奇王志毅
Owner MATERIAL INST OF CHINA ACADEMY OF ENG PHYSICS
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