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Manufacturing method for tungsten or molybdenum based uranium dioxide fuel pellet

A technology for uranium dioxide and a manufacturing method, which is applied in the field of nuclear fuel preparation, can solve problems such as unimproved continuity of tungsten pellets, poor continuity of tungsten substrates for pellets, and high requirements for special equipment, and achieve improved continuity of metal substrates, tungsten ( Molybdenum) metal matrix has good continuity, and the effect of reducing manufacturing difficulty and cost

Active Publication Date: 2019-08-23
CHINA INSTITUTE OF ATOMIC ENERGY
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Problems solved by technology

However, the method reported in the literature is still mechanically mixing tungsten powder and uranium dioxide powder, which still cannot solve the disadvantage of poor continuity of the tungsten (molybdenum) matrix after the uranium dioxide phase content in the pellet is high.
[0013] Therefore, these three methods have their own advantages and disadvantages. The pellet tungsten (molybdenum) substrate produced by vapor deposition-hot isostatic pressing method has better continuity, but it requires high special equipment, complicated process and high sintering temperature; The pressure sintering method has low requirements on equipment and simple process, but requires extremely high sintering temperature, and the prepared pellet tungsten (molybdenum) matrix has poor continuity; spark plasma sintering method has simple process and low sintering temperature, but the pellet tungsten (molybdenum) matrix has poor continuity. ) matrix continuity is still not improved

Method used

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  • Manufacturing method for tungsten or molybdenum based uranium dioxide fuel pellet
  • Manufacturing method for tungsten or molybdenum based uranium dioxide fuel pellet
  • Manufacturing method for tungsten or molybdenum based uranium dioxide fuel pellet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Embodiment 1: the manufacture of tungsten or molybdenum-based uranium dioxide fuel pellets (1)

[0042] Weigh 23g of uranium dioxide powder, pre-press it into a pre-pressed compact under a pressure of 50MPa on a hydraulic press, crush it, pass through a 20-mesh sieve, add 0.6% (m / m) of paraffin, spheroidize and mix evenly, and then add 27g The metal tungsten powder is mixed evenly to obtain powder raw materials that can be used for pressing.

[0043] Weigh 5g of powder raw material, fill it into a cemented carbide mold with a diameter of 12.20mm, apply a pressure of 100MPa to the mold, hold the pressure for 60s, and then demould to obtain a pellet compact.

[0044] Put the pellet compact into a crucible, put it into a sintering furnace, start sintering after vacuuming, the heating rate does not exceed 5°C / min, heat up to 250°C for 3 hours, and maintain a high vacuum in the furnace during the holding process. After the heat preservation is completed, Ar gas containing 2...

Embodiment 2

[0045] Embodiment 2: the manufacture of tungsten or molybdenum-based uranium dioxide fuel pellets (two)

[0046] Weigh 30.86g of uranium dioxide powder, pre-press it into a pre-pressed compact under a pressure of 50 MPa on a hydraulic press, crush it, pass through a 20-mesh sieve, add 0.6% (m / m) of paraffin, spheroidize and mix evenly, and then add 19.14g metal molybdenum powder is mixed evenly, obtains the powder raw material that can be used for pressing.

[0047] Weigh 5g of powder raw material, fill it into a cemented carbide mold with a diameter of 12.20mm, apply a pressure of 400MPa to the mold, hold the pressure for 20s, and demould to obtain a pellet compact.

[0048] Put the pellet compact into a crucible, put it into a sintering furnace, start sintering after vacuuming, the heating rate does not exceed 5°C / min, heat up to 250°C for 3 hours, and maintain a high vacuum in the furnace during the holding process. After the heat preservation is completed, Ar gas containi...

Embodiment 3

[0049] Embodiment 3: the manufacture of tungsten or molybdenum-based uranium dioxide fuel pellets (three)

[0050] Weigh 34.72g of uranium dioxide powder, put it into a crucible, heat up to 100°C in a calciner, and keep it warm in an air atmosphere for 4 hours. The obtained powder is pre-pressed into a pre-pressed compact under a pressure of 50 MPa on a hydraulic press, crushed through a 20-mesh sieve, added 0.3% (m / m) zinc stearate, spheroidized and mixed evenly, and then added 15.28 g of metal The tungsten powder is mixed evenly to obtain a powder raw material that can be used for pressing.

[0051] Weigh 5g of powder raw material, fill it into a cemented carbide mold with a diameter of 12.04mm, apply a pressure of 300MPa to the mold, hold the pressure for 30s, and demould to obtain a pellet compact.

[0052] Put the pellet compact into the crucible, put it into the sintering furnace, start sintering after vacuuming, the heating rate does not exceed 5°C / min, heat up to 600°...

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Abstract

The invention belongs to the technical field of nuclear fuel preparation, and relates to a manufacturing method for a tungsten or molybdenum based uranium dioxide fuel pellet. The manufacturing methodsequentially comprises the following steps: (1) preparing a pelletized powder raw material for pressing by a binder or a lubricant, metal tungsten or molybdenum powder and uranium dioxide powder; (2)filling the pelletized powder raw material into a mould to press, thereby obtaining pellet compact; and (3) putting the pellet compact into a sintering furnace, sintering after vacuum-pumping, and keeping high vacuum in the sintering furnace, wherein a heating rate does not exceed 5 DEG C per minute before a volatilization temperature of the binder or the lubricant added into powdered raw material preparation reaches; and after the binder or the lubricant is removed, increasing the heating rate to continuously sinter, thereby obtaining a tungsten or molybdenum based uranium dioxide fuel pellet finished product. The manufacturing method provided by the invention is relatively simple in process flow, is relatively low in sintering temperature, is relatively good in tungsten (molybdenum) metallic matrix continuity, and can reduce producing and manufacturing difficulty and cost of the fuel pellet.

Description

technical field [0001] The invention belongs to the technical field of nuclear fuel preparation and relates to a method for manufacturing tungsten or molybdenum-based uranium dioxide fuel pellets. Background technique [0002] In the field of reactors, the most widely used nuclear fuel is oxide fuel, such as uranium dioxide fuel and mixed oxide (UO 2 -PuO 2 )fuel. The tungsten (molybdenum)-based uranium dioxide fuel disperses uranium dioxide powder particles in a continuous metal tungsten (molybdenum) matrix, and utilizes the high thermal conductivity of metal tungsten (molybdenum) to convert the uranium dioxide fuel phase The fission heat is quickly taken away, so as to achieve the characteristics of high working temperature and high fuel consumption. [0003] Compared with pure uranium dioxide fuel, tungsten (molybdenum)-based uranium dioxide fuel has significantly improved thermal conductivity (such as figure 1 , 2 Shown), the 3-8W / m·K of uranium dioxide fuel is grea...

Claims

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Application Information

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IPC IPC(8): C22C1/05C22C1/10C22C29/12G21C21/02
CPCC22C1/051C22C29/005C22C29/12G21C21/02Y02E30/30
Inventor 屈哲昊尹邦跃王轩任劲如魏国良
Owner CHINA INSTITUTE OF ATOMIC ENERGY
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