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Method for preparing uranium dioxide composite fuel pellets by doping graphene oxide

A technology of uranium dioxide and composite fuel, which is applied in the direction of reactor fuel material, reactor fuel element, manufacturing reactor, etc., can solve the problems of segregation, agglomeration, low uniformity and production efficiency of graphene, and the difference in density and other physical properties. Achieve the effects of improving hydrophilicity, reducing raw material costs, and improving thermal conductivity

Active Publication Date: 2022-07-01
CHINA INSTITUTE OF ATOMIC ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But graphene and UO 2 The density and other physical properties vary greatly, making it difficult for graphene to be uniformly doped into UO 2 In pellets (relevant foreign research mainly adopts physical mixing and spark plasma sintering technology, there are problems such as uniformity and low production efficiency; domestic reports use graphene doped UO 2 Pellets, which require ultrasonic dispersion during mixing
However, graphene is very prone to segregation and agglomeration problems, which will affect the uniformity of the powder, so graphene is directly used to prepare uniformly doped UO 2 Pellets are difficult)

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Example 1: Preparation of uranium dioxide composite fuel pellets

[0029] (1) Take 180 mL of uranyl nitrate solution with a concentration of 500 g / L and an acidity of 1.5 mol / L HNO 3 , to wherein adding 40g content is the graphene oxide suspension of 1% (m / m), after mixing, slowly add 400mL concentrated ammonia water, make the pH of solution be 10-12, obtain the ammonium diuranate (ammonium diuranate) containing graphene oxide ( ADU) precipitation.

[0030] (2) Filtration of the precipitate obtained in step (1), the filter cake is dried, pulverized and sieved in a vacuum drying oven to obtain an ammonium diuranate-graphene oxide composite with an average particle size of 0.1-10 μm.

[0031] (3) The ammonium diuranate-graphene oxide composite obtained in step (2) was transferred into a quartz boat, sent into a muffle furnace, heated to 350° C. by introducing nitrogen, and then heated to 550° C. and calcined for 2 hours to obtain UO 3 . The temperature was raised to 68...

Embodiment 2

[0034] Example 2: Preparation of intermediate products and detection of final uranium dioxide composite fuel pellets

[0035] The intermediate products prepared in Example 1 and the uranium dioxide composite fuel pellets finally obtained were tested as follows.

[0036] (1) Detection of uranium dioxide complex powder

[0037] According to GB / T 11847-2008 "BET Capacity Method for Determination of Specific Surface Area of ​​Uranium Dioxide Powder", the specific surface area of ​​uranium dioxide composite powder prepared by doping graphene oxide was tested, and the result was that the specific surface area of ​​the composite was 10.05m 2 / g, and UO without graphene oxide 2 The specific surface area of ​​the control sample is 3.01m 2 / g.

[0038] According to GB / T 11842-89 "Uranium dioxide powder and pellets determination of oxygen-uranium atomic ratio by thermogravimetric method", the oxygen-uranium ratio was determined, and the result was that the oxygen-uranium ratio of the ...

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Abstract

The invention belongs to the technical field of nuclear fuel preparation, and relates to a method for preparing uranium dioxide composite fuel pellets by doping graphene oxide. The preparation method comprises the following steps: (1) adding graphene oxide to the uranyl nitrate solution, adding ammonia water after mixing evenly to obtain ammonium diuranate precipitation containing graphene oxide; (2) filtering the precipitation, and the filter cake is subjected to drying, pulverizing, and sieving to obtain an ammonium diuranate-graphene oxide composite; (3) calcining the ammonium diuranate-graphene oxide composite, and then further heating the ammonium diuranate-graphene oxide composite under a hydrogen reducing atmosphere to obtain a carbon dioxide uranium powder; (4) cold pressing the uranium dioxide powder into a mold, demoulding to obtain a green body; (5) sintering the green body in a reducing atmosphere to obtain a uranium dioxide composite fuel pellet. Using the preparation method of the present invention, a novel composite fuel pellet with high thermal conductivity can be prepared, thereby improving the safety of the nuclear reactor during operation.

Description

technical field [0001] The invention belongs to the technical field of nuclear fuel preparation, and relates to a method for preparing uranium dioxide composite fuel pellets by doping graphene oxide. Background technique [0002] At present, ceramic uranium dioxide pellets are widely used as reactor fuel in the world. Ceramic uranium dioxide has many advantages, such as good nuclear physical properties, good radiation stability, high melting point of 2800 ° C, only one crystal form within the melting point, and isotropy. However, the thermal conductivity of ceramic uranium dioxide is only one tenth of that of metal uranium, and the thermal conductivity decreases with the increase of temperature. At the core temperature, if the heat transfer from the pellets to the coolant is not smooth, it is easy to cause local overheating of the pellets, resulting in swelling and rupture of the cladding. [0003] In order to improve the thermal conductivity of fuel pellets and improve th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/51C04B35/622C04B35/626G21C3/62G21C21/02
CPCC04B35/51C04B35/622C04B35/62605G21C3/623G21C21/02C04B2235/425C04B2235/6582C04B2235/656C04B2235/6567C04B2235/96C04B2235/9607Y02E30/30
Inventor 朱礼洋张燕杨志红杨素亮田国新杜江平冯海宁
Owner CHINA INSTITUTE OF ATOMIC ENERGY
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