US20020050335A1 - Fabrication process of uranium foil having fine grains solidified rapidly from melt using cooling roll, and the fabrication apparatus - Google Patents

Fabrication process of uranium foil having fine grains solidified rapidly from melt using cooling roll, and the fabrication apparatus Download PDF

Info

Publication number
US20020050335A1
US20020050335A1 US09/836,478 US83647801A US2002050335A1 US 20020050335 A1 US20020050335 A1 US 20020050335A1 US 83647801 A US83647801 A US 83647801A US 2002050335 A1 US2002050335 A1 US 2002050335A1
Authority
US
United States
Prior art keywords
uranium
foil
melt
fabrication
chamber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US09/836,478
Inventor
Chang-Kyu Kim
Ki-Hwan Kim
Seok-Jin Oh
Se-Jung Jang
Eung-Soo Kim
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Korea Atomic Energy Research Institute KAERI
Korea Electric Power Corp
Original Assignee
Korea Atomic Energy Research Institute KAERI
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Korea Atomic Energy Research Institute KAERI filed Critical Korea Atomic Energy Research Institute KAERI
Assigned to KOREA ELECTRIC POWER CORPORATION, KOREA ATOMIC ENERGY RESEARCH INSTITUTE reassignment KOREA ELECTRIC POWER CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: JANG, SE-JUNG, KIM, CHANG-KYU, KIM, EUNG-SOO, KIM, KI-HWAN, OH, SEOK-JIN
Publication of US20020050335A1 publication Critical patent/US20020050335A1/en
Priority to US10/393,978 priority Critical patent/US6860317B2/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
    • B22D11/0637—Accessories therefor
    • B22D11/0697—Accessories therefor for casting in a protected atmosphere
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
    • B22D11/0622—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by two casting wheels
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C43/00—Alloys containing radioactive materials

Definitions

  • the present invention relates generally to a fabrication process for uranium foil having fine crystalline grains solidified rapidly from a melt using cooling rolls, and foil fabrication apparatus.
  • the present invention relates to low or high enrichment uranium and uranium alloy foil, the fabrication apparatus, and the fabrication process therefore wherein uranium (U) and uranium alloy [U—(A)Q—(B)X—(C)Y (Q: Al, Fe, Ni, Si, Cr, Zr element, X: Al, Fe, Ni, Si, Cr, Zr element, Y: Al, Fe, Ni, Si, Cr, Zr element, Q ⁇ X ⁇ Y, (A) ⁇ 1 wt %, (B) ⁇ 1 wt %, (C) ⁇ 1 wt %)] foils are directly cast from a melt, not through a vacuum induction melting & casting, ingot-cutting, hot-rolling and heat-treatment process, but through a twin-roll-casting process.
  • the conventional fabrication method for uranium foil has the disadvantages of complicated processes as follows: casting the uranium or the uranium alloy after holding at about 1300° C. in a vacuum induction furnace; cutting the resulting rod-type ingot to suitable size for hot rolling at 600° C. or higher; rolling through many passes a thick piece of the ingot to gradually thin it to fabricate a uranium foil of 100-200 ⁇ m thickness; and finally heat-treatment at 800° C. and quenching the fabricated uranium foil to produce the required gain size and orientation.
  • the uranium In the conventional method, the uranium must be heated and rolled under vacuum or in an inert atmosphere because it is a reactive material. The hot rolling is repeated several times to obtain a suitable thickness of the uranium foil. As the hot-rolling process takes long time, productivity is relatively low. A washing/drying process must be done to remove surface impurities after hot rolling. In order to obtain the fine grain structure which has a more stable behavior during irradiation, heat-treatment and quenching must be performed. The high hardness and low ductility of uranium or uranium alloy make it difficult to roll the foil. The foil is liable to crack owing to residual stress during the process, resulting in a low yield. The present invention is expected to improve the economy of producing uranium foil, due to a higher productivity and yield than the conventional method.
  • a uranium foil having excessive residual stress from hot rolling may be deformed or damaged during thermal cycling during irradiation. Furthermore, deformed areas or cracks generated during thermal cycling may act as penetration paths through which there can be an interdiffusion reaction of the uranium with a coating layer, such as Al or Ni, which serves as a protector against the reaction of the uranium with a fixed tube in an irradiation target.
  • a coating layer such as Al or Ni
  • the present invention aims to alleviate the problems as described above.
  • Low or high enrichment uranium and uranium alloy foil are fabricated through twin-roll casting of a uranium melt without a hot-rolling process and heat-treatment process.
  • An improvement in productivity and process economics due to process simplification and better quality from the absence of any residual stress on the foil are expected.
  • the said objects of the present invention can be achieved by providing a uranium foil solidified rapidly by twin-roll casting, and an apparatus and a method for fabricating the same.
  • the present invention is achieved by providing an apparatus and a method for fabricating the uranium foil wherein low or high enrichment uranium and alloy element material are weighed and then charged into a heat-resistant crucible equipped with a tundish having a slot.
  • the crucible is mounted at the inner part of a vacuum chamber in which a vacuum of 10 ⁇ 3 torr or higher can be maintained by a vacuum pump system.
  • the uranium and the alloying elements are melted by high frequency electric power.
  • the alloy melt is fed through the slot to the space between side dams and two rotating rolls driven by an electric motor, and thin foil is formed by pressing the partly solidified melt with the cold rolls.
  • the foil produced is further cooled by supplying inert cooling gas.
  • FIG. 1 shows a schematic view of a configuration of an apparatus for fabricating the uranium foil according to the present invention.
  • FIG. 1 With reference to FIG. 1, there is an apparatus for fabricating the uranium foil by twin rolls according to the present invention.
  • the apparatus of the present invention comprises: a heat-resistant crucible ( 2 ), a tundish having a slot ( 1 ), an induction coil ( 3 ) connected to a high-frequency generation apparatus (not shown) to increase the temperature of the crucible ( 2 ), a vacuum pump system ( 5 ) for evacuating the chamber ( 4 ) to an appropriate degree of vacuum, a roller ( 6 ) installed in the chamber ( 4 ), side dams with a resistance heater (not shown) for preventing a rapid decrease of the uranium melt temperature after pouring from the crucible and for guiding the uranium melt into the roller ( 6 ), a gas-feeding valve ( 7 ) for supplying a cooling gas into the chamber ( 4 ), and a recovery container ( 8 ) for collecting the fabricated foil.
  • Uranium and alloy elements are charged at the lower part of the heat-resistant crucible ( 2 ) mounted at the upper part of the chamber ( 4 ). Also a stopper ( 9 ) is installed in the crucible.
  • the induction coil ( 3 ) mounted around the heat-resistant crucible ( 2 ) superheats the charged material to about 200° C. higher than the melting temperature by the high frequency generation apparatus.
  • the vacuum pump system ( 5 ) allows an inner part of the chamber ( 4 ) to be evacuated to a suitable vacuum of 10 ⁇ 3 torr or higher and is connected to one side of the chamber ( 4 ).
  • the roller ( 6 ) is positioned in the same central plane as the slot ( 1 ) in the chamber ( 4 ). Also, the roller is operated by an electric motor (not shown) to manufacture the uranium foil from an alloy melt poured through the slot ( 1 ). The preheated side dams (not shown) prevent the rapid decrease of the uranium melt temperature after pouring from the crucible and guide the uranium melt into the roller ( 6 ).
  • the alloy melt fed through the slot ( 1 ) is fabricated into uranium foil by the rotating rolls driven by the electric motor, and the resulting foil is rapidly cooled under argon or helium cooling gas.
  • the recovery container ( 8 ) at the bottom part of the chamber ( 4 ) collects the thin foil ( 10 ) manufactured in the chamber ( 4 ).
  • uranium material is charged into a heat-resistant crucible ( 2 ) having a slot ( 1 ).
  • the crucible ( 2 ) and an insulation material (not shown) are assembled in proper order in a fabrication apparatus.
  • the steel chamber in the apparatus equipped with the crucible ( 2 ) is evacuated to a vacuum of 10 ⁇ 3 torr or higher by a vacuum pump system ( 5 ).
  • a high frequency generator ( 3 ) is operated to superheat the charge material of the crucible to a temperature of about 200° C. higher than the melting temperature of the uranium.
  • the poured alloy melt passes through the slot ( 1 ) of 1-mm width and then is fed to the space between the preheated side dams (not shown) and the roller ( 6 ) rotating at about 300 rpm to form the thin foil ( 10 ).
  • a gas-feeding valve ( 7 ) is operated to supply the chamber ( 4 ) with the inert cooling gas, whereby the foil ( 10 ) fabricated by the roller ( 6 ) is rapidly solidified (at a rate greater than 10 3 ° C./sec).
  • a uranium foil having fine and randomly orientated grains is directly obtained by such a rapid solidification effect, it is not necessary to heat-treat the foil and quench from about 800° C. to form fine grains.
  • the uranium foil is collected within a recovery container ( 8 ) installed at the bottom of the chamber ( 4 ).
  • the foil in the recovery container ( 8 ) is about 125 ⁇ m thick and the foil with an acceptable thickness is recovered at about 90% yield.
  • a piece of uranium foil prepared as previously described is assembled with other components to fabricate an irradiation target, in order to charge into a reactor for producing fission isotope 99 Mo, the only parent nuclide of 99m Tc, which is an extremely useful tool for medical diagnosis.
  • This invention is applied to a uranium alloy of low or high enrichment uranium [U—(A)Q—(B)X—(C)Y (Q: Al, Fe, Ni, Si, Cr, Zr elements, X: Al, Fe, Ni, Si, Cr, Zr elements, Y: Al, Fe, Ni, Si, Cr, Zr elements, Q ⁇ X ⁇ Y, (A) ⁇ 1 wt %, (B) ⁇ 1 wt %, (C) ⁇ 1 wt %)] foil for the irradiation target.
  • uranium and alloy elements including Fe, Al and Ni are appropriately weighed according to the desired alloy composition and charged to the crucible.
  • the steel chamber ( 4 ) is evacuated to 10 ⁇ 3 torr or higher using the vacuum pump system ( 5 ) as described in a fabrication procedure for uranium foil.
  • the high frequency generator ( 3 ) is operated to superheat the charge material of the crucible to a temperature about 200° C. higher than the melting temperature of the uranium alloy.
  • the discharged alloy melt passes through the slot ( 1 ) of 1.2 mm width and then is fed to the space between the preheated side dams (not shown) and the roller ( 6 ) rotating at the high speed of 300 rpm to form the thin foil ( 10 ).
  • the gas-feeding valve ( 7 ) is operated to inject the inert cooling gas into the chamber ( 4 ), whereby the foil ( 10 ) fabricated by the roller ( 6 ) is quickly solidified (10 3 ° C./sec or faster).
  • the uranium alloy foil having fine and randomly orientated grains is directly obtained by such a rapid solidification effect, it is not necessary to heat-treat the hot rolled foil and quench from about 800° C. to form fine grains.
  • the uranium alloy foil is collected within a container ( 8 ) installed at the bottom of the chamber ( 4 ).
  • the foil in the recovery container ( 8 ) is about 150 ⁇ m thick, and foil with a suitable thickness is recovered at a 90% or higher yield.
  • a piece of uranium foil prepared as previously described is assembled with other components to fabricate an irradiation target, in order to charge into a reactor for producing fission isotope 99 Mo, the only parent nuclide of 99m Tc, which is an extremely useful tool for medical diagnosis.
  • the fabrication process of uranium alloy foil by the present invention is greatly simplified compared to the conventional fabrication method, which includes a vacuum induction melting process, a repetitive hot-rolling process, a washing/drying process for removing impurities, such as surface oxides, and a heat-treatment process for obtaining fine isotropic grains.
  • the melt of uranium or uranium alloy is rapidly cooled to directly fabricate the uranium foil, the uranium or uranium foil, being difficult to roll due to its high toughness, can be easily fabricated.
  • a long time period is required to conduct the repetitive troublesome conventional hot-rolling process to adjust the thickness of a uranium ingot.
  • the alloy melt may be cast at once to fabricate large amounts of the foil in a few minutes by the present invention, thereby having a high productivity.
  • the uranium foil may be damaged and cracked owing to an induced stress during the hot-rolling process, which leads to a low yield and a reduced economic efficiency.
  • the foil fabrication process by rapid solidification of the present invention has a 90% or higher yield through which several kilograms of the foil can be directly fabricated in a few minutes.
  • the foil fabrication process using preheated side dams and a cooling roller, facilitates control of the width of the foil. Accordingly, the yield of uranium is very high and the economics are highly favorable because enriched uranium is very expensive.
  • foil fabricated by twin rolling has smaller stress than foil obtained through repetitive hot rolling of a uranium plate. Accordingly, deformation or cracking of the foil generated by thermal cycling during the irradiation process can be prevented. Defects in deformation areas or cracks can act as penetration paths for elements in the coating layer of the target. The interaction between coating layer and target will be enhanced by the defects or cracks. However, the foil fabricated by the present invention does not have such paths.
  • uranium foil undergoes large anisotropic growth during irradiation in a reactor.
  • the uranium foil of the present invention has homogeneous and fine grains with random orientation so as to prevent the uranium foil from excessively growing during irradiation.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Continuous Casting (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

The present invention is concerned with the fabrication process of low or high enrichment uranium and uranium alloy foil, and the fabrication apparatus therefor. Uranium (U) and uranium alloy [U—(A)Q—(B)X—(C)Y (Q: Al, Fe, Ni, Si, Cr, Zr element, X: Al, Fe, Ni, Si, Cr, Zr element, Y: Al, Fe, Ni, Si, Cr, Zr element, Q≠X≠Y, (A)≦1 wt %, (B)≦1 wt %, (C)≦1 wt %)] foil are directly obtained from a melt, not through a vacuum induction melting & casting, ingot cutting, hot-rolling and heat-treatment process, but through melt spinning or a twin-roll casting process. Major advantages have been obtained as follows: 1) a simplified process without the hot-rolling process and heat-treatment process, 2) an improvement in productivity and process economics in foil fabrication, and 3) a high purity and a high quality of the foil.

Description

    BACKGROUND OF THE INVENTION
  • 1. Field of the Invention [0001]
  • The present invention relates generally to a fabrication process for uranium foil having fine crystalline grains solidified rapidly from a melt using cooling rolls, and foil fabrication apparatus. In particular, the present invention relates to low or high enrichment uranium and uranium alloy foil, the fabrication apparatus, and the fabrication process therefore wherein uranium (U) and uranium alloy [U—(A)Q—(B)X—(C)Y (Q: Al, Fe, Ni, Si, Cr, Zr element, X: Al, Fe, Ni, Si, Cr, Zr element, Y: Al, Fe, Ni, Si, Cr, Zr element, Q≠X≠Y, (A)≦1 wt %, (B)≦1 wt %, (C)≦1 wt %)] foils are directly cast from a melt, not through a vacuum induction melting & casting, ingot-cutting, hot-rolling and heat-treatment process, but through a twin-roll-casting process. [0002]
  • 2. Description of the Prior Art [0003]
  • Generally, the conventional fabrication method for uranium foil has the disadvantages of complicated processes as follows: casting the uranium or the uranium alloy after holding at about 1300° C. in a vacuum induction furnace; cutting the resulting rod-type ingot to suitable size for hot rolling at 600° C. or higher; rolling through many passes a thick piece of the ingot to gradually thin it to fabricate a uranium foil of 100-200 μm thickness; and finally heat-treatment at 800° C. and quenching the fabricated uranium foil to produce the required gain size and orientation. [0004]
  • In the conventional method, the uranium must be heated and rolled under vacuum or in an inert atmosphere because it is a reactive material. The hot rolling is repeated several times to obtain a suitable thickness of the uranium foil. As the hot-rolling process takes long time, productivity is relatively low. A washing/drying process must be done to remove surface impurities after hot rolling. In order to obtain the fine grain structure which has a more stable behavior during irradiation, heat-treatment and quenching must be performed. The high hardness and low ductility of uranium or uranium alloy make it difficult to roll the foil. The foil is liable to crack owing to residual stress during the process, resulting in a low yield. The present invention is expected to improve the economy of producing uranium foil, due to a higher productivity and yield than the conventional method. [0005]
  • Meanwhile, a uranium foil having excessive residual stress from hot rolling may be deformed or damaged during thermal cycling during irradiation. Furthermore, deformed areas or cracks generated during thermal cycling may act as penetration paths through which there can be an interdiffusion reaction of the uranium with a coating layer, such as Al or Ni, which serves as a protector against the reaction of the uranium with a fixed tube in an irradiation target. [0006]
    • SUMMARY OF THE INVENTION
  • The present invention aims to alleviate the problems as described above. Low or high enrichment uranium and uranium alloy foil are fabricated through twin-roll casting of a uranium melt without a hot-rolling process and heat-treatment process. An improvement in productivity and process economics due to process simplification and better quality from the absence of any residual stress on the foil are expected. [0007]
  • Accordingly, the said objects of the present invention can be achieved by providing a uranium foil solidified rapidly by twin-roll casting, and an apparatus and a method for fabricating the same. [0008]
  • More specifically, the present invention is achieved by providing an apparatus and a method for fabricating the uranium foil wherein low or high enrichment uranium and alloy element material are weighed and then charged into a heat-resistant crucible equipped with a tundish having a slot. The crucible is mounted at the inner part of a vacuum chamber in which a vacuum of 10[0009] −3 torr or higher can be maintained by a vacuum pump system. Then, the uranium and the alloying elements are melted by high frequency electric power. The alloy melt is fed through the slot to the space between side dams and two rotating rolls driven by an electric motor, and thin foil is formed by pressing the partly solidified melt with the cold rolls. The foil produced is further cooled by supplying inert cooling gas.
    •  BRIEF DESCRIPTION OF THE DRAWING
  • The above objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawing, in which: [0010]
  • FIG. 1 shows a schematic view of a configuration of an apparatus for fabricating the uranium foil according to the present invention.[0011]
    • DETAILED DESCRIPTION OF THE INVENTION
  • With reference to FIG. 1, there is an apparatus for fabricating the uranium foil by twin rolls according to the present invention. [0012]
  • The apparatus of the present invention comprises: a heat-resistant crucible ([0013] 2), a tundish having a slot (1), an induction coil (3) connected to a high-frequency generation apparatus (not shown) to increase the temperature of the crucible (2), a vacuum pump system (5) for evacuating the chamber (4) to an appropriate degree of vacuum, a roller (6) installed in the chamber (4), side dams with a resistance heater (not shown) for preventing a rapid decrease of the uranium melt temperature after pouring from the crucible and for guiding the uranium melt into the roller (6), a gas-feeding valve (7) for supplying a cooling gas into the chamber (4), and a recovery container (8) for collecting the fabricated foil.
  • Uranium and alloy elements are charged at the lower part of the heat-resistant crucible ([0014] 2) mounted at the upper part of the chamber (4). Also a stopper (9) is installed in the crucible. The induction coil (3) mounted around the heat-resistant crucible (2) superheats the charged material to about 200° C. higher than the melting temperature by the high frequency generation apparatus.
  • The vacuum pump system ([0015] 5) allows an inner part of the chamber (4) to be evacuated to a suitable vacuum of 10−3 torr or higher and is connected to one side of the chamber (4).
  • The roller ([0016] 6) is positioned in the same central plane as the slot (1) in the chamber (4). Also, the roller is operated by an electric motor (not shown) to manufacture the uranium foil from an alloy melt poured through the slot (1). The preheated side dams (not shown) prevent the rapid decrease of the uranium melt temperature after pouring from the crucible and guide the uranium melt into the roller (6).
  • The alloy melt fed through the slot ([0017] 1) is fabricated into uranium foil by the rotating rolls driven by the electric motor, and the resulting foil is rapidly cooled under argon or helium cooling gas.
  • The gas-feeding valve ([0018] 7), connected to the chamber (4), feeds inert argon or helium cooling gas into the chamber (4) to rapidly cool the uranium foil fabricated by the cooling roller (6).
  • The inert argon or helium cooling gas, flowing into the chamber ([0019] 4) through the gas-feeding valve (7), is injected into the chamber (4) through gas nozzles mounted at the upper part of the chamber (4).
  • The recovery container ([0020] 8) at the bottom part of the chamber (4) collects the thin foil (10) manufactured in the chamber (4).
  • A better understanding of the present invention may be obtained in light of the following examples which are set forth to illustrate, but are not to be construed to limit, the present invention. [0021]
    • EXAMPLE 1
  • To fabricate low or high enrichment uranium foil, uranium material is charged into a heat-resistant crucible ([0022] 2) having a slot (1). The crucible (2) and an insulation material (not shown) are assembled in proper order in a fabrication apparatus.
  • Then, the steel chamber in the apparatus equipped with the crucible ([0023] 2) is evacuated to a vacuum of 10−3 torr or higher by a vacuum pump system (5).
  • A high frequency generator ([0024] 3) is operated to superheat the charge material of the crucible to a temperature of about 200° C. higher than the melting temperature of the uranium.
  • When the rotation speed of the roller ([0025] 6) driven by the electric motor is stabilized at about 300 rpm, a stopper (9) placed in the crucible (2) is lifted upward to discharge an alloy melt.
  • The poured alloy melt passes through the slot ([0026] 1) of 1-mm width and then is fed to the space between the preheated side dams (not shown) and the roller (6) rotating at about 300 rpm to form the thin foil (10).
  • Then, a gas-feeding valve ([0027] 7) is operated to supply the chamber (4) with the inert cooling gas, whereby the foil (10) fabricated by the roller (6) is rapidly solidified (at a rate greater than 103° C./sec).
  • Because a uranium foil having fine and randomly orientated grains is directly obtained by such a rapid solidification effect, it is not necessary to heat-treat the foil and quench from about 800° C. to form fine grains. The uranium foil is collected within a recovery container ([0028] 8) installed at the bottom of the chamber (4).
  • The foil in the recovery container ([0029] 8) is about 125 μm thick and the foil with an acceptable thickness is recovered at about 90% yield.
  • A piece of uranium foil prepared as previously described is assembled with other components to fabricate an irradiation target, in order to charge into a reactor for producing fission isotope [0030] 99Mo, the only parent nuclide of 99mTc, which is an extremely useful tool for medical diagnosis.
    • EXAMPLE 2
  • This invention is applied to a uranium alloy of low or high enrichment uranium [U—(A)Q—(B)X—(C)Y (Q: Al, Fe, Ni, Si, Cr, Zr elements, X: Al, Fe, Ni, Si, Cr, Zr elements, Y: Al, Fe, Ni, Si, Cr, Zr elements, Q≠X≠Y, (A)≦1 wt %, (B)≦1 wt %, (C)≦1 wt %)] foil for the irradiation target. [0031]
  • For the fabrication of U-500 ppm Fe-1200 ppm Al-500 ppm Ni alloy foil, uranium and alloy elements including Fe, Al and Ni are appropriately weighed according to the desired alloy composition and charged to the crucible. The steel chamber ([0032] 4) is evacuated to 10−3 torr or higher using the vacuum pump system (5) as described in a fabrication procedure for uranium foil.
  • As such, when the crucible ([0033] 2) and the insulation material (not shown) are assembled in the proper order in the apparatus, the high frequency generator (3) is operated to superheat the charge material of the crucible to a temperature about 200° C. higher than the melting temperature of the uranium alloy.
  • When the rotation speed of the roller ([0034] 6) operated by the electric motor is stabilized at about 300 rpm, the stopper (9) placed in the crucible (2) is lifted upward to feed the alloy melt.
  • The discharged alloy melt passes through the slot ([0035] 1) of 1.2 mm width and then is fed to the space between the preheated side dams (not shown) and the roller (6) rotating at the high speed of 300 rpm to form the thin foil (10).
  • Then, the gas-feeding valve ([0036] 7) is operated to inject the inert cooling gas into the chamber (4), whereby the foil (10) fabricated by the roller (6) is quickly solidified (103° C./sec or faster).
  • Because the uranium alloy foil having fine and randomly orientated grains is directly obtained by such a rapid solidification effect, it is not necessary to heat-treat the hot rolled foil and quench from about 800° C. to form fine grains. The uranium alloy foil is collected within a container ([0037] 8) installed at the bottom of the chamber (4).
  • The foil in the recovery container ([0038] 8) is about 150 μm thick, and foil with a suitable thickness is recovered at a 90% or higher yield.
  • A piece of uranium foil prepared as previously described is assembled with other components to fabricate an irradiation target, in order to charge into a reactor for producing fission isotope [0039] 99Mo, the only parent nuclide of 99mTc, which is an extremely useful tool for medical diagnosis.
  • The fabrication process of uranium alloy foil by the present invention is greatly simplified compared to the conventional fabrication method, which includes a vacuum induction melting process, a repetitive hot-rolling process, a washing/drying process for removing impurities, such as surface oxides, and a heat-treatment process for obtaining fine isotropic grains. [0040]
  • Since the melt of uranium or uranium alloy is rapidly cooled to directly fabricate the uranium foil, the uranium or uranium foil, being difficult to roll due to its high toughness, can be easily fabricated. [0041]
  • A long time period is required to conduct the repetitive troublesome conventional hot-rolling process to adjust the thickness of a uranium ingot. In contrast, the alloy melt may be cast at once to fabricate large amounts of the foil in a few minutes by the present invention, thereby having a high productivity. [0042]
  • In addition, because the uranium is lacking in ductility, the uranium foil may be damaged and cracked owing to an induced stress during the hot-rolling process, which leads to a low yield and a reduced economic efficiency. [0043]
  • However, the foil fabrication process by rapid solidification of the present invention has a 90% or higher yield through which several kilograms of the foil can be directly fabricated in a few minutes. The foil fabrication process, using preheated side dams and a cooling roller, facilitates control of the width of the foil. Accordingly, the yield of uranium is very high and the economics are highly favorable because enriched uranium is very expensive. [0044]
  • Furthermore, foil fabricated by twin rolling has smaller stress than foil obtained through repetitive hot rolling of a uranium plate. Accordingly, deformation or cracking of the foil generated by thermal cycling during the irradiation process can be prevented. Defects in deformation areas or cracks can act as penetration paths for elements in the coating layer of the target. The interaction between coating layer and target will be enhanced by the defects or cracks. However, the foil fabricated by the present invention does not have such paths. [0045]
  • Commonly, uranium foil undergoes large anisotropic growth during irradiation in a reactor. However, the uranium foil of the present invention has homogeneous and fine grains with random orientation so as to prevent the uranium foil from excessively growing during irradiation. [0046]
  • The present invention has been described in an illustrative matter, and it is to be understood that the terminology used is intended to be of the nature of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. [0047]

Claims (2)

What is claimed is:
1. A method for fabricating a uranium foil having fine randomly oriented grains by rapidly solidifying a melt of uranium or uranium alloy directly using a cooling roller, wherein the uranium alloy is U—(A)Q—(B) X—(C)Y, in which Q is selected from the group consisting of Al, Fe, Ni, Si, Cr, and Zr elements, X is selected from the group consisting of Al, Fe, Ni, Si, Cr, and Zr elements, and Y is selected from the group consisting of Al, Fe, Ni, Si, Cr, and Zr elements, and Q≠X≠Y, (A)≦1 wt %, (B)≦1wt %, (C)≦1 wt %.
2. An apparatus for fabricating a uranium foil having fine randomly oriented grains by solidifying rapidly a melt of uranium or uranium alloy directly using a cooling roller, comprising
a heat-resistant crucible (2) equipped with a tundish having a slot (1),
an induction coil (3) connected to a high frequency generating apparatus (not shown) to heat the crucible (2),
a vacuum pump system (5) for obtaining an appropriate vacuum within the chamber (4),
a roller (6) and side dams (not shown) installed in the chamber (4),
a gas-feeding valve (7) for feeding gas into the chamber (4) and
a recovery container (8) for collecting the fabricated foil.
US09/836,478 2000-10-31 2001-04-18 Fabrication process of uranium foil having fine grains solidified rapidly from melt using cooling roll, and the fabrication apparatus Abandoned US20020050335A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US10/393,978 US6860317B2 (en) 2000-10-31 2003-03-24 Method and apparatus for producing uranium foil and uranium foil produced thereby

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR00-64237 2000-10-31
KR10-2000-0064237A KR100388808B1 (en) 2000-10-31 2000-10-31 Uranium foil having fine grains solidified rapidly from melt by cooling roll directly, and the fabrication apparatus and the fabrication process

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US10/393,978 Continuation-In-Part US6860317B2 (en) 2000-10-31 2003-03-24 Method and apparatus for producing uranium foil and uranium foil produced thereby

Publications (1)

Publication Number Publication Date
US20020050335A1 true US20020050335A1 (en) 2002-05-02

Family

ID=19696341

Family Applications (1)

Application Number Title Priority Date Filing Date
US09/836,478 Abandoned US20020050335A1 (en) 2000-10-31 2001-04-18 Fabrication process of uranium foil having fine grains solidified rapidly from melt using cooling roll, and the fabrication apparatus

Country Status (6)

Country Link
US (1) US20020050335A1 (en)
EP (1) EP1203832B1 (en)
JP (1) JP3416660B2 (en)
KR (1) KR100388808B1 (en)
CN (1) CN1212908C (en)
CA (1) CA2347209C (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004028724A1 (en) * 2002-09-27 2004-04-08 Postech Foundation Method and apparatus for producing amorphous alloy sheet, and amorphous alloy sheet produced using the same
US7100670B1 (en) * 2003-09-12 2006-09-05 The United States Of America As Represented By The United States Department Of Energy Method for fabricating uranium foils and uranium alloy foils
AU2003259592B2 (en) * 2003-03-31 2010-02-04 Korea Atomic Energy Research Institute Method and apparatus for producing uranium foil and uranium foil produced thereby
CN105689660A (en) * 2016-02-26 2016-06-22 沈阳广泰真空科技有限公司 Double-faced cooling multifunctional efficient vacuum rapid-condensing furnace
CN108213389A (en) * 2017-12-29 2018-06-29 安徽高德铝业有限公司 A kind of door and window aluminium alloy extrusions processing technology of vacuum pouring forming
CN108637197A (en) * 2018-05-24 2018-10-12 钢铁研究总院 A kind of big heat size, high-efficiency and continuous prepare the vacuum quick quenching device and method of amorphous band
US11027330B2 (en) 2016-08-10 2021-06-08 Nucor Corporation Method of thin strip casting
RU2760902C1 (en) * 2021-05-11 2021-12-01 Российская Федерация, от имени которой выступает Государственная корпорация по атомной энергии "Росатом" Uranium-based alloy (options)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100485926B1 (en) * 2002-06-24 2005-04-29 한국수력원자력 주식회사 Method and apparatus for Continuous casting of uranium rod
KR100467440B1 (en) * 2002-07-30 2005-01-24 한국수력원자력 주식회사 Cutting apparatus of uranium rod
KR100470935B1 (en) * 2002-07-30 2005-02-21 한국수력원자력 주식회사 Transfer apparatus of uranium rod
KR100666702B1 (en) * 2005-05-04 2007-01-11 동아대학교 산학협력단 Fabrication device of rheology material by using vacuum chamber
CN103658573B (en) * 2013-12-09 2015-06-03 武汉钢铁(集团)公司 Liquid alloy vacuum melting single-roller melt-spinning method and device
KR101640237B1 (en) 2015-04-28 2016-07-22 한국원자력연구원 Manufacturing method of uranium aluminide powder and uranium aluminide powder using thereof
CN114309505B (en) * 2021-12-17 2023-01-10 北京科技大学 Metal thin strip continuous casting method adopting momentum flow distribution
CN115094351B (en) * 2022-07-05 2023-01-24 西安交通大学 Depleted uranium-based hydrogen absorption and storage alloy and method

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5536052A (en) * 1978-09-06 1980-03-13 Pioneer Electronic Corp Manufacturing method of magnetic sheet
CA1135933A (en) * 1979-07-18 1982-11-23 Robert Thomson Method and apparatus for casting elongated members of reactive metals and reactive metal alloys
US4592411A (en) * 1983-01-17 1986-06-03 Allied Corporation Method of and apparatus for continuously casting metal filament in a vacuum
JPS60111744A (en) * 1983-11-24 1985-06-18 Nec Corp Quick cooling device for liquid
JPH01271039A (en) * 1988-04-20 1989-10-30 Mitsubishi Electric Corp Manufacture of thin berylium-copper sheet
JPH05337614A (en) * 1992-04-06 1993-12-21 Nippon Steel Corp Production of single roll solidified strip by rapid cooling
JPH05287307A (en) * 1992-04-15 1993-11-02 Seiko Epson Corp Production of alloy for rare-erath bond magnet
JPH11179499A (en) * 1997-12-15 1999-07-06 Fuji Electric Co Ltd Vacuum float-up melting and continuous casting apparatus and method thereof

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004028724A1 (en) * 2002-09-27 2004-04-08 Postech Foundation Method and apparatus for producing amorphous alloy sheet, and amorphous alloy sheet produced using the same
US20060102315A1 (en) * 2002-09-27 2006-05-18 Lee Jung G Method and apparatus for producing amorphous alloy sheet, and amorphous alloy sheet produced using the same
AU2003259592B2 (en) * 2003-03-31 2010-02-04 Korea Atomic Energy Research Institute Method and apparatus for producing uranium foil and uranium foil produced thereby
US7100670B1 (en) * 2003-09-12 2006-09-05 The United States Of America As Represented By The United States Department Of Energy Method for fabricating uranium foils and uranium alloy foils
CN105689660A (en) * 2016-02-26 2016-06-22 沈阳广泰真空科技有限公司 Double-faced cooling multifunctional efficient vacuum rapid-condensing furnace
US11027330B2 (en) 2016-08-10 2021-06-08 Nucor Corporation Method of thin strip casting
CN108213389A (en) * 2017-12-29 2018-06-29 安徽高德铝业有限公司 A kind of door and window aluminium alloy extrusions processing technology of vacuum pouring forming
CN108637197A (en) * 2018-05-24 2018-10-12 钢铁研究总院 A kind of big heat size, high-efficiency and continuous prepare the vacuum quick quenching device and method of amorphous band
RU2760902C1 (en) * 2021-05-11 2021-12-01 Российская Федерация, от имени которой выступает Государственная корпорация по атомной энергии "Росатом" Uranium-based alloy (options)
WO2022240311A1 (en) * 2021-05-11 2022-11-17 Российская Федерация, от имени которой выступает Государственная корпорация по атомной энергии "Росатом" Uranium-based alloy (variants)

Also Published As

Publication number Publication date
EP1203832A3 (en) 2002-05-15
KR20020033961A (en) 2002-05-08
KR100388808B1 (en) 2003-06-25
JP3416660B2 (en) 2003-06-16
CA2347209A1 (en) 2002-04-30
CN1350896A (en) 2002-05-29
JP2002143990A (en) 2002-05-21
CA2347209C (en) 2009-12-01
EP1203832B1 (en) 2004-08-11
CN1212908C (en) 2005-08-03
EP1203832A2 (en) 2002-05-08

Similar Documents

Publication Publication Date Title
EP1203832B1 (en) Fabrication process of uranium foil having fine grains solidified rapidly from melt using roll, and the fabrication apparatus
JP3325900B2 (en) Method and apparatus for producing polycrystalline silicon, and method for producing silicon substrate for solar cell
CN113122763B (en) Preparation method of high-strength high-toughness high-entropy alloy
CN104704139B (en) Cu Ga alloy sputtering targets and its manufacture method
EP0460234B1 (en) Sheet of titanium-aluminum intermetallic compound and process for producing the same
EP0784350B1 (en) Method for producing hydrogen-absorbing alloy
EP0202336B1 (en) Process for producing a thin plate of a high ferrosilicon alloy
EP0389821A1 (en) Continuous thin sheet of titanium-aluminium intermetallic compound and process for producing same
CN116607028B (en) Smelting method of refractory high-entropy alloy
JPS6327407B2 (en)
JPH06287661A (en) Production of smelted material of refractory metal
JP3553487B2 (en) Silicon ribbon manufacturing equipment
CN110484742B (en) Method for preparing Fe-W intermediate alloy by electron beam melting and high purification
JPH10246578A (en) Skull melting furnace and production of high purity alloy using it
CN115821122B (en) Block nano-stacking fault aluminum alloy material and preparation and cold rolling methods thereof
CN110408871A (en) A kind of tantalum, niobium, tantalum alloy and niobium alloy crystal fining method
CN101724775B (en) Prepration method for forming ZrO2 nanoparticles in molten steel
JPH05277656A (en) Thin plate of alloy containing ti3al group intermetallic compound and manufacture thereof
US6860317B2 (en) Method and apparatus for producing uranium foil and uranium foil produced thereby
Kim et al. An investigation of the fabrication technology for uranium foils by cooling-roll casting
Kim et al. Fabrication and characteristics of U-MO foils for a monolithic fuel by the cooling-roll casting method
Kim et al. Development of the fabrication technology of wide uranium foils for Mo-99 irradiation target by cooling-roll casting method
CN117753932A (en) Preparation method of nickel-vanadium alloy cast ingot
JPH04190959A (en) Manufacture of hydrogen occluding alloy
Kobayashi Novel Processing Methods for Superplastic Alloys

Legal Events

Date Code Title Description
AS Assignment

Owner name: KOREA ELECTRIC POWER CORPORATION, KOREA, REPUBLIC

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KIM, CHANG-KYU;KIM, KI-HWAN;OH, SEOK-JIN;AND OTHERS;REEL/FRAME:011724/0033

Effective date: 20010326

Owner name: KOREA ATOMIC ENERGY RESEARCH INSTITUTE, KOREA, REP

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KIM, CHANG-KYU;KIM, KI-HWAN;OH, SEOK-JIN;AND OTHERS;REEL/FRAME:011724/0033

Effective date: 20010326

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION