Preparation method of honeycomb fuel pellet

A technology of fuel pellets and honeycomb shape, which is applied in the field of preparation of honeycomb fuel pellets, can solve the problems of enlarging the scrap rate of grinding, reducing the production yield of pellets, complex shape of pellets, etc., and achieves the realization of external dimension control, Easy control of external dimensions and uniform internal density

Active Publication Date: 2019-08-23
CHINA INSTITUTE OF ATOMIC ENERGY
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AI Technical Summary

Problems solved by technology

[0013] 1) The shape of the pellet is complex, the mold design is more complicated, and the pressure transmission inside the powder is more difficult. On the one hand, it leads to a substantial increase in pressing defects and a decrease in the yield of the green compact; on the other hand, the difficulty of pressure transmission leads to the uneven density of the pellet uniform
[0014] 2) The uneven compact density of the pellets leads to inconsistent sintering shrinkage of the pellets in the subsequent sintering process, and the shape of the pellets is deformed, which increases the workload of the grinding process, and at the same time, the demand for more grinding processes further enlarges the pellets Grinding scrap rate due to internal defects reduces overall pellet production yield
[0015] The above problems make the honeycomb fuel pellets unable to be produced by the existing conventional nuclear fuel pellet production process, and a new production process needs to be developed

Method used

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  • Preparation method of honeycomb fuel pellet
  • Preparation method of honeycomb fuel pellet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] Embodiment 1: Preparation of honeycomb fuel pellets (1)

[0045] Weigh UO 2 Powder 50g, paraffin wax powder 0.5g. Will UO 2 The powder is filled into the mold and pre-pressed on a hydraulic press with a pre-pressing pressure of 50MPa. The pre-pressed compact is crushed, and the large particles obtained by crushing are sieved and poured into ZrO together with 0.5g of paraffin wax powder 2 Ball mill jar, put ZrO 2 The balls are subjected to high-energy ball milling, and the conditions are: the volume ratio of the ball to material is 3:1, the milling speed is 300 rpm, and the ball milling time is 48 hours. The powder obtained by ball milling is sieved for later use.

[0046]Weigh 4 g of the granulated powder and fill it into a cemented carbide mold, apply a pressure of 500 MPa to the mold on a hydraulic press, hold the pressure for 5 seconds, and demould to obtain a pellet compact.

[0047] First dewax the pellet compact, the dewaxing temperature is 600°C, the dewaxi...

Embodiment 2

[0048] Embodiment 2: the preparation of honeycomb fuel pellet (two)

[0049] Weigh 50g of UN powder and 1g of paraffin wax powder. Fill the UN powder into the mold and pre-press on the hydraulic press with a pre-press pressure of 80MPa. The pre-pressed compact is crushed, and the large particles obtained by crushing are sieved and poured into ZrO together with 1g of paraffin wax powder. 2 Ball mill jar, put ZrO 2 The balls are subjected to high-energy ball milling, and the conditions are: the volume ratio of the ball to material is 4:1, the milling speed is 400 rpm, and the ball milling time is 32 hours. The powder obtained by ball milling is sieved for later use.

[0050] Weigh 4 g of the granulated powder and fill it into a cemented carbide mold, apply a pressure of 300 MPa to the mold on a hydraulic press, hold the pressure for 30 seconds, and then release the mold to obtain a pellet compact.

[0051] Dewax the pellet compact first, the dewaxing temperature is 400°C, th...

Embodiment 3

[0052] Embodiment 3: Preparation of honeycomb fuel pellets (three)

[0053] Weigh UO 2 -W powder 50g, paraffin wax powder 2.5g. Will UO 2 -W powder is filled into the mold and pre-pressed on a hydraulic press with a pre-pressing pressure of 100MPa. The pre-press compact is crushed, and the large particles obtained by crushing are sieved and poured into ZrO together with 2.5g of paraffin wax powder. 2 Ball mill jar, put ZrO 2 The balls are subjected to high-energy ball milling, and the conditions are: the volume ratio of the ball to material is 5:1, the ball milling speed is 500 rpm, and the ball milling time is 16 hours. The powder obtained by ball milling is sieved for later use.

[0054] Weigh 4 g of the granulated powder and fill it into a cemented carbide mold, apply a pressure of 50 MPa to the mold on a hydraulic press, hold the pressure for 60 seconds, and then demould to obtain a pellet compact.

[0055] Put the pellet compact into a tungsten crucible and start de...

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Abstract

The invention belongs to the technical field of nuclear fuel preparation, and relates to a preparation method of a honeycomb fuel pellet. The preparation method which does not include a grinding stepsequentially comprises the following steps: (1) granulating: weighing raw material powder particles, filling a mold with the raw material powder particles, pre-pressing the raw material powder particles in a hydraulic machine, crushing a pre-pressed green body, sieving the crushed green body to obtain large particles, mixing the large particles with a binder, pouring the obtained mixture into a ball mill jar, placing grinding balls in the jar, and performing high-energy ball milling; (2) pressing: sieving the obtained ball-milled powder, filling the mold with the large particles, pressing thelarge particles, and demolding the pressed large particles to obtain a pellet pressed body; and (3) sintering: dewaxing the pellet pressed body, placing the dewaxed pellet pressed body in a burning boat, and placing and sintering the burning boat in a sintering furnace to obtain the finished honeycomb fuel pellet. The preparation method of the honeycomb fuel pellet of the invention has the advantages of realization of the production of the nuclear fuel pellet with a complicated shape by using the existing nuclear fuel production line, omission of the grinding process, increase of the production efficiency and reduction of the production cost.

Description

technical field [0001] The invention belongs to the technical field of nuclear fuel preparation, and relates to a method for preparing honeycomb fuel pellets. Background technique [0002] At present, the most widely used form of fuel pellets in reactor fuel technology is solid cylindrical pellets or cylindrical pellets with a central hole. The conventional powder metallurgy process is generally used for processing and manufacturing. This process is relatively mature and generally includes manufacturing Granulation, pressing, sintering, grinding and other processes, the main conditions of each process are as follows. [0003] 1) Granulation [0004] The main purpose of granulation is to improve the compaction performance of pellet raw material powder, reduce the possibility of defects in compaction, so as to achieve the purpose of controlling the quality of pellets. Granulation is generally the pellet raw material powder (such as the most common UO 2 Powder) is pre-presse...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G21C21/02G21C21/10
CPCG21C21/02G21C21/10Y02E30/30
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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