KR101312583B1 - Manufacturing non-proliferational nuclear metallic fuel applying electric current and compressive force to metallic powder at low temperature - Google Patents

Abstract

The present invention relates to a method for manufacturing a metal fuel rod containing bubbles by loading a raw material in the form of metal powder into a cylindrical mold, applying a current up and down, and compressing to form a bond between particles at low temperature.

Metallic fuels are being developed as fuel for the next generation of nuclear power. Raw materials for metal fuels are generally manufactured using a pyrochemical process and consequently take the form of metal powders. The production of the metal fuel developed until now has been using a method of solidifying or hot-melting the metal powder by casting at high temperature. However, if the spent fuel material must be continuously recycled through nuclear conversion, the loss of nuclear material is a problem due to the vaporization of volatile elements such as americium (Am) in the powder. The use of a nonvolatile low temperature process is preferred to promote.

In the present invention, the metal powder is loaded into a tube made of a non-conductive material and the powder is bonded while intermittently applying current while compressing the rod-shaped conductive electrodes on the upper and lower sides to maintain the temperature of the nuclear fuel rod in a low temperature region where the nuclear material does not volatilize. A method of manufacturing a rod-shaped metal nuclear fuel rod with nuclear non-proliferation and proper density was devised.

Description

Manufacturing non-proliferational nuclear metallic fuel applying electric current and compressive force to metallic powder at low temperature}

1 is a schematic diagram of a method for manufacturing a low-temperature non-proliferative metal fuel that simultaneously applies a current and a compressive force to a powder raw material.

Figure 2 is a system configuration for producing a low temperature nuclear non-proliferating metal fuel according to the present invention.

DESCRIPTION OF THE REFERENCE SYMBOLS

(1) pressure drive shaft (2) insulated compression force and current transfer

(3) Airtight Seal Box (4) Plunger

(5) Insulated rod fuel molds (Die) (6) Loaded fuel powder

(7) Cooling system (8) Gas entrance for atmosphere control

(9) current connection wire

A technology is developed to convert long-lived radioactive waste, such as spent nuclear fuel, from a nuclear conversion device into a short-lived nuclear material, so that the initial high-level waste contains only a small amount of high-level waste, or the whole is converted to low-level waste. . In this process, making the nuclear fuel for conversion into metal form has the advantage of making the most of the dry process using molten salt. Since all high-level wastes do not disappear at once in the nuclear converter, the remaining high-level wastes are collected, dried again into metal fuel, and repeatedly burned in the nuclear converter. At this time, the nuclear fuel material collected in the dry process is a metal powder and includes various nuclides such as uranium, plutonium, neptinium, americium and curium. In the nuclear fuel production method currently being developed, the powder collected by the vacuum molten metal casting method is loaded into a vacuum furnace, melted at a high temperature of about 1500 degrees Celsius using induction electricity, and cast to obtain a rod-shaped high density nuclear fuel. Since the above method is a high temperature process, it causes a loss of volatile substances such as americium, and thus has the disadvantage of lowering the nuclear diffusion resistance and the extinction efficiency of the high level waste.

The present invention aims to produce a nuclear fuel with a high density by forming a junction between powder particles using a current at a low temperature, but to prevent the loss of volatile nuclear materials at the source, thereby enhancing the nuclear proliferation resistance and increasing the efficiency of high level waste extinction. .

In order to achieve the object as described above, the present invention provides a method and apparatus for manufacturing a low temperature nuclear non-proliferative metal fuel that simultaneously applies a current and a compressive force to the powder raw material, the manufacturing method is a nuclear fuel encapsulated in a sealed box of vacuum Loading the fuel powder into the mold and then sealing the sealed phase difference;

Intermittently applying a current to the fuel powder;

Applying a compressive force from top to bottom simultaneously with applying the current

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The temperature in the mold may be above room temperature 600 degrees Celsius or less.

The compressive force may be greater than or equal to atmospheric pressure and less than 50000 psi.

Forming a cooling device for cooling around the nuclear fuel mold may initially supply any one of water and low temperature gas for low temperature formation, and may provide a refrigerant for cooling during the process.

In addition, as a low-temperature non-proliferative metal fuel manufacturing apparatus that applies a current and a compressive force to the powder raw material at the same time,

Cylindrical fuel molds

A compression rod positioned at an upper portion of the mold and connected to a pressure driving shaft to provide a compression force in a vertical direction to the nuclear fuel powder provided in the mold;

A cooling tube formed outside the mold to keep the mold at a low temperature initially and to distribute a refrigerant for cooling during the process;

It may include a current connecting line connected to the top and bottom of the nuclear fuel mold in order to flow the current in the mold.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings.

The equipment, manufacturing method and procedure of the present invention are as follows.

1. Powder-voltage powder metallurgy equipment

(1) Insulation molds of length and diameter suitable for the dimensions of the target metal nuclear fuel rods are made of materials of sufficient strength. At this time, in the case of a conductive material mold, an insulating tube made of non-conductive ceramic or high strength synthetic resin is inserted into the inner surface.

(2) Compression force and current transmitting part are also manufactured to have sufficient strength and insulation.

(3) Compression drive shaft is manufactured by Servo-electric type or Servo-hydraulic type to measure drive load and drive displacement continuously and exchange information with integrated control device to control drive shaft feedback.

(4) Atmosphere control boxes are to be constructed to maintain a reducing gas environment to prevent oxidation of metal fuel. To this end, a vacuum pump for removing initial internal air and a gas inlet for oxygen concentration control should be provided.

(5) The current supply device determines the capacity of the fuel to prevent the melting of the fuel during short-term energization based on the electrical resistance of the target fuel.

(6) The current controller is designed to apply variable current and time pulse current for optimal process based on information such as temperature, displacement, resistance, and breakdown voltage received from the state diagnosis device.

(7) The mold cooling device is initially formed at low temperature with water or low temperature gas, and is manufactured to remove heat generated during the process.

2. Nuclear Non-Proliferative Metal Fuel Manufacturing Process

(1) Based on the design density and dimensions of the final metal fuel, the weight of the nuclear fuel is quantified to load the powder and sealed in an airtight box to form a reducing atmosphere.

(2) The mold cooling device is initially formed at low temperature with water or low temperature gas, and the refrigerant is continuously supplied to remove heat generated during the process.

(3) Promote the joining of powder particles by intermittently applying current and compression displacement. Instantaneous density is evaluated by measuring the displacement of the drive shaft and the dynamic load.

(4) Repeat the above step (3) until the density reaches the design value.

Figure 1 is a simplified diagram of a device for producing a nuclear fuel, in order to produce a nuclear fuel is loaded with a fuel powder in a cylindrical fuel mold (5) and the fuel is compressed in a vertical direction with a compression rod (4) this compression force Is generated from the upper pressure drive shaft (1) and transmitted to the compression rod (4). At this time, the compression rod is applied to the loaded powder, the compression force is intermittently transmitted to the fuel powder and at the same time the current is applied to the fuel powder, the compression force and the current is applied intermittently until the density of the fuel powder reaches a predetermined design value.

At this time, the mold cooling apparatus formed around the mold cools the mold by using a refrigerant such as water and air to draw out heat generated during the compression process to the outside, and the temperature in the mold is not higher than 600 degrees Celsius above room temperature. . In addition, the compressive force applied by the compression rod is to be at least 50000psi above atmospheric pressure.

2 shows a block diagram of an apparatus for driving the apparatus according to the present invention. Compression driving device drives the compression rod that provides the compressive force. Current control device intermittently supplies the current to the nuclear fuel powder. The condition diagnosis device checks the temperature and pressure in the mold and integrates the process based on the data. The control unit performs feedback control to drive the compression drive unit and the current control unit.

According to the invention as described above, by forming a junction between the powder particles by using a current at a low temperature to produce a nuclear fuel with a high density, but to prevent the loss of volatile nuclear material at the source to increase the nuclear proliferation resistance and to increase the efficiency of high-level waste extinction Has an effect.

Claims (5)

As a low temperature nuclear non-proliferative metal fuel manufacturing method that applies a current and a compressive force to the fuel powder at the same time, Loading nuclear fuel powder into a nuclear fuel mold encapsulated in a vacuum sealed box and then encapsulating the sealed phase difference; Intermittently applying a current to the fuel powder; Applying a compressive force from top to bottom simultaneously with applying the current A method of manufacturing a low temperature nuclear non-proliferative metal fuel comprising simultaneously applying a current and a compressive force to a nuclear fuel powder The method of claim 1, wherein the temperature in the mold is at least 600 degrees Celsius above room temperature. The method of claim 1, wherein the compressive force is greater than atmospheric pressure and less than 50000 psi, simultaneously applying current and compression force to the fuel powder. The method of claim 1, wherein a cooling device for cooling is formed around the nuclear fuel mold to initially supply one of water and low temperature gas for low temperature formation, and provide a refrigerant for cooling during the process. Method for Manufacturing Low Temperature Nuclear Non-Proliferative Metal Fuel by Simultaneously Applying Current and Compression Force to Fuel Fuel Powders  It is a low-temperature non-proliferative metal fuel manufacturing apparatus that applies the current and compression force to the fuel powder at the same time, Cylindrical fuel molds A compression rod positioned at an upper portion of the mold and connected to a pressure driving shaft to provide a compression force in a vertical direction to the nuclear fuel powder provided in the mold; A cooling tube formed outside the mold to keep the mold at a low temperature initially and to distribute a refrigerant for cooling during the process; Low temperature nuclear non-proliferative metal fuel production apparatus for applying current and compression force simultaneously to the fuel powder, including a current connecting line connected to the top and bottom of the fuel mold in order to flow the current in the mold

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