KR101483873B1 - Nuclear fuel cladding structure of sodium-cooled fast reactor capable of preventing fuel-cladding chemical interaction and method of manufacturing the same - Google Patents

Abstract

The present invention relates to nuclear fuel cladding for a sodium-cooled fast reactor. According to the present invention, the nuclear fuel cladding for a sodium-cooled fast reactor comprises outer cladding, a liner layer, and a middle layer. The outer cladding is made of at least ferrite-martensite steel including HT9 steel or austenite-martensite steel including Grade 92 steel. The liner layer is prepared on the inner surface of the outer cladding and prevents fuel-cladding chemical interaction (FCCI) between nuclear fuel and the outer cladding. The middle layer is prepared between the outer cladding and the liner layer; prevents interaction between the outer cladding and the liner layer; and increases adhesion between the outer cladding and the liner layer. The outer cladding and the liner layer with the middle layer in between are co-drawing-molded using a co-drawing mold and integrated into a cladding structure. As a result, the present invention can reduce FCCI between nuclear fuel and the cladding, improve adhesion between the cladding and a liner, prevent inter-diffusion between the cladding and the liner caused by neutrons, and physically separate the cladding from the nuclear fuel, thereby significantly improving the safety of the cladding.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a nuclear fuel cladding tube for preventing fuel-cladding interaction, and a method for manufacturing the cladding tube.

The present invention relates to a method of manufacturing a nuclear fuel cladding tube and a cladding thereof, and more particularly, to a fuel cladding chemical interaction (FCCI) method of a sodium- cooled fast reactor (SFR) And a method of manufacturing the same.

Generally, a fourth-generation future nuclear reactor system, the sodium-cooled fast reactor (SFR), is a nuclear reactor that uses fission neutrons to generate nuclear fission. As a raw material, It is possible to reduce the amount of spent fuel in light water reactors, which is becoming a problem as well as maximizing uranium resources, and is considered as a potential candidate for next generation nuclear reactors to be built in the future.

SFR fuel is produced by a pyro-processing process in which oxidized spent fuel is melted in molten salt after dry processing and then processed into metal by electrolytic reduction. From this point of view, metallic fuel is strongly considered as SRF fuel.

The metal nuclear fuel of SFR reactor has advantages of high power core design due to high thermal conductivity and excellent nuclear diffusion resistance in connection with pyro processing, but the actinide elements such as uranium and plutonium, which are the main constituents of metal nuclear fuel, (FCCI) and common phenomenon at contact with stainless steels at an operating temperature of 650 ° C or higher, resulting in a thinner nuclear fuel cladding, resulting in weakened nuclear fuel integrity.

Several countermeasures have been proposed to prevent the existing FCCI. Various coating methods have been attempted to prevent FCCI by physically separating the cladding tube and the nuclear fuel. However, SFR fuel cladding tubes are seamless steel tubes with an outer diameter and a thickness of 9 mm and 0.6 mm and a length of 3.7 m or more, It has been concluded provisionally that the coating of the diffusion preventing material on the inner surface of the narrow and long pipe of the present invention is practically impossible to achieve practical use.

In this regard, various countermeasures have been proposed. For example, in the case of Japanese Patent JP 199400293 U, a technique of forming a film by electrolytic plating has been proposed. The electrolytic plating method has a high economic efficiency, but has disadvantages such as a problem of plating cracking during plating and a limitation in selection of a plating material. In addition, there is an attempt to form a film by applying PVD, CVD, oxidizing / nitriding method, etc. However, due to disadvantages such as impossibility of practical application to a small diameter tube such as a nuclear fuel cladding for SFR, It can not be applied to nuclear power plants.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a nuclear fuel cladding structure having a structure that can prevent chemical interaction between a nuclear fuel and a cladding tube of a nuclear reactor, And a method for producing the same.

Another object of the present invention is to provide a nuclear fuel cladding tube capable of forming a structure capable of preventing the interaction (FCCI) between an SFR fuel cladding tube having a small outer diameter and a small thickness and a nuclear fuel at low cost and a method of manufacturing the same will be.

In order to achieve the above object, a nuclear cladding tube of a sodium-cooled high-speed furnace according to the present invention comprises a cladding tube composed of a ferrite or austenite martensitic steel including HT9 and Grade 92 and a cladding tube provided on the inner surface of the cladding tube, (FCCI) between the cladding and the liner layer to prevent interaction between the cladding and the liner layer due to neutrons originating from the fuel, And a liner layer having an intermediate layer formed thereon, and the clad pipe are subjected to a cord drawing-forming process using a mold for co-drawing molding to form a core having a diameter of less than 1 cm And is formed integrally with a cladding structure.

In the cladding tube, the intermediate layer may be formed on the liner surface using physical vapor deposition.

In the cladding tube, Cr, Zr, V, SiC, Si, Sn, Nb or Ti may be used as the intermediate layer material.

In the cladding tube, the intermediate layer may be formed to a thickness of 1 to 5 탆.

In the cladding tube, the liner may be formed to a thickness of 20 to 100 탆.

A method for manufacturing a nuclear fuel cladding tube according to the present invention comprises the steps of preparing a liner having an intermediate layer formed on its surface, preparing a cladding tube, and a mold for co-drawing molding the liner and cladding tube Forming a cladding structure having a diameter of less than 1 cm and integrally forming a cladding layer having a diameter of less than 1 cm, the intermediate layer being formed of a mixture of a cladding material and a liner And is formed by using a substance that enhances adhesiveness.

In the method of manufacturing the cladding tube, the intermediate layer may be formed on the surface of the liner using physical vapor deposition.

In the method of manufacturing the cladding tube, Cr, Zr, V, SiC, Si, Sn, Nb or Ti may be used as the intermediate layer material.

In the method of manufacturing the cladding tube, the intermediate layer may be formed to a thickness of 1 to 5 탆.

In the method of manufacturing the cladding tube, the liner may be formed to a thickness of 20 to 100 탆.

In the method of manufacturing the cladding tube, the cladding tube may be composed of ferrite or austenite martensitic steel including HT9 and Grade 92.

According to the present invention, unlike a conventional nuclear fuel cladding tube, a liner having an intermediate layer deposited on an inner surface of a cladding tube provides a cladding structure composed of a liner / intermediate layer / cladding tube. Therefore, it is possible to reduce the FCCI phenomenon between the cladding tube and the fuel, to improve the adhesion between the cladding tube and the liner, to prevent mutual diffusion due to neutrons between the cladding tube and the liner, and to physically isolate the cladding tube and the fuel, The safety of the cladding pipe can be greatly improved.

1 shows a structure of an SFR fuel cladding tube according to an embodiment of the present invention;
FIG. 2 is a schematic view illustrating a process of forming an intermediate layer on a surface of a liner by rotating a liner according to an embodiment of the present invention using physical vapor deposition. FIG.
3 is a schematic view illustrating a process of simultaneously forming a liner having an intermediate layer according to the present invention and a cladding tube integrally using a codrawing process.
Fig. 4 is a schematic view showing the nose drawing of Fig. 3 three-dimensionally. Fig.
5 is a diagram showing the interaction (FCCI) phenomenon between the nuclear fuel cladding and the nuclear fuel.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, a structure well known in the art, for example, a co-drawing process itself, a mold used in the process itself, etc. are already well known, and a description thereof will be omitted. Even if these explanations are omitted, those skilled in the art will readily understand the characteristic configuration of the present invention.

1 is a view showing the structure of an SFR fuel cladding tube according to an embodiment of the present invention.

Referring to FIG. 1, the nuclear fuel cladding tube 1 according to the present invention includes a jacket tube 30 and a plurality of openings 30 for preventing interaction (FCCI) between the jacket tube 30 and the nuclear fuel, A liner 10 provided on the inner surface of the outer tube 30 and a liner 10 provided between the liner 10 and the outer tube 30 for improving the adhesion between the liner 10 and the closure tube 1 And further comprises an intermediate layer (20) provided to further protect said cladding tube (1).

That is, according to the present invention, the liner 10 and the intermediate layer 20 are provided on the inner surface of the outer tube 30 to physically isolate the outer tube 30 from the nuclear fuel, ) And the liner (10).

In one embodiment of the present invention, the SFR nuclear envelope tube 30 is composed of ferrite martensite steel or austenite martensite steel. For example, HT9 can be used as a ferrite martensitic steel, which is composed of 12 wt% of Cr, 1 wt% of Mo, 0.17 wt% of C, 0.25 wt% of Si, 0.5 wt% of Ni %, And so on. As a kind of austenite martensite steel, Grade 92 can be used. It is a steel containing 9 wt% of Cr and 0.5 wt% of Mo and containing iron as a base element. Such cladding tubes are typically formed of seamless steel tubes having an outer diameter of 9 mm and a thickness of 0.6 mm and a length of 3.7 m or more.

The liner 10 for preventing FCCI reaction between the outer tube 30 and the nuclear fuel comprises one of Zr (zirconium), V (vanadium), Cr (chromium), In (indium), and Pd (palladium) In one embodiment, it is formed to a thickness of 20 to 100 mu m. The heat transfer efficiency is lowered from the viewpoint of heat transfer and the power generation efficiency of the nuclear power generation is reduced, so that the liner 10 is formed in the thickness range for economical reasons.

Even if the liner 10 is formed on the inner surface of the outer tube 30, it may cause thermal diffusion between the liner 10 and the outer tube 30 at a temperature of about 600 ° C. . In order to improve the adhesion between the liner 10 and the outer tube 30 and to suppress the mutual diffusion reaction between the liner 10 and the outer tube 30, ) And the outer tube (30). Zr, V, SiC, Si, Sn, Nb, Ti, Ti, and the like, for the secondary fission reaction by the neutron while minimizing the neutron absorption while achieving the above- In, Pd, or the like. At this time, the intermediate layer 20 is preferably formed to have a thickness of 1 to 5 탆. That is, when the thickness of the intermediate layer 20 is less than 1 탆, it is difficult to achieve the object of preventing the mutual diffusion between the liner 10 and the outer tube 30, and when it is thicker than 5 탆, It is preferable to form it within the above-mentioned thickness range.

Meanwhile, as described above, the outer tube 30 is generally a nonmetallic steel tube having an outer diameter and a thickness of 9 mm and 0.6 mm and a length of 3.7 m or more. The inner surface of the narrow and long outer tube 30 It is difficult to form the liner 10 and the intermediate layer 20 as described above. Therefore, in the present invention, the structure of the cladding tube 1 is formed using a co-drawing process.

In other words, it is practically impossible to form the liner 10 and the intermediate layer 20 on the inner surface of the envelope tube 30 having the above-mentioned size once. Therefore, in the present invention, the above structure is realized by using a cord drawing process.

Specifically, first, the material constituting the intermediate layer 20 is deposited on the surface of the liner material (rod-like material) forming the liner layer 10 (see FIG. 2). As the method for forming the intermediate layer 20, PVD, PLD, CVD, E-beam, and electroplating may be used.

For example, a plasma deposition apparatus 40 may be used to deposit the material constituting the intermediate layer 20 on the liner 10 layer. When the material 41 constituting the intermediate layer 20 is bonded to one pole of the power source unit 42 of the plasma deposition apparatus 40, On the outer circumferential surface of the liner (10).

Next, as shown in FIGS. 3 and 4, the liner 10 on which the intermediate layer 20 is deposited and the sheath tube 30 are subjected to cord drawing-forming by using a die for cord drawing molding, A tube-shaped cladding structure as shown in Fig. 1 can be obtained. It is practically impossible to separately form a separate layer on the inner surface of the cladding to which the present invention is applied by using a deposition or electrolytic reaction. Therefore, conventionally, a cladding tube consisting essentially of a single layer has been generally used. However, according to the present invention, the liner 10 and the sheath tube 30, on which the intermediate layer 20 is deposited, and the sheathing tube 30 are formed by a mechanical molding process called " There is an advantage that a cladding structure can be realized.

Specifically, the metal mold for cord drawing molding is inserted into a hole formed in the cladding tube 1 to prevent the cladding tube 1 from being distorted during molding, and the cladding tube 1 is formed into a cylindrical shape An inner mandrel 51 and an insert 52 in close contact with the outer circumferential surface of the closure tube 1 to reduce the diameter of the closure tube 1 and an outer backing 53 surrounding the insert 52 do.

The inner surface of the insert 52 is formed as an inclined surface, and the diameter of the cladding tube 1 is reduced while adhering to the insert 52.

As noted above, the present invention is intended to prevent interactions (FCCI) between nuclear fuel cladding and nuclear fuel in nuclear reactors, particularly sodium-cooled fast reactors (SFRs). That is, as shown in FIG. 6, the nuclear fuel is diffused into the cladding during operation of the reactor, and the reaction layer is formed in accordance with the diffusion, whereby the thickness of the cladding tube becomes gradually thinner, and the safety of the reactor is lowered. However, since the cladding of a nuclear reactor installed and operated in Korea is constituted solely by a cladding tube itself, there is a possibility of causing a problem with respect to safety. Therefore, with respect to a nuclear fuel cladding tube used in a sodium- Similarly, a structure that can prevent such FCCI phenomenon is required.

While the present invention has been described with reference to specific embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. That is, the embodiments can be variously modified and modified within the scope of the claims, which are also within the scope of the present invention. Accordingly, the invention is limited only by the claims and the equivalents thereof.

10: liner 20: middle layer
30: cladding tube

Claims (11)

An envelope tube composed of ferrite or austenite martensitic steel including at least HT9 and Grade 92;
A liner layer provided on an inner surface of the outer tube to prevent a chemical interaction reaction (FCCI) between the nuclear fuel and the outer tube; And
An intermediate layer provided between the sheath tube and the liner layer to prevent mutual reaction between the sheath tube and the liner layer and increase adhesion between the sheath tube and the liner layer;
/ RTI >
Wherein the intermediate layer is deposited on the outer circumferential surface of the liner layer in the form of fine particles by the plasma deposition apparatus,
Wherein said liner layer and said sheath tube are of a cladding structure in the form of a tube using a die for forming a cord. The method according to claim 1,
Wherein the intermediate layer is formed on the surface of the liner using physical vapor deposition. 3. The method of claim 2,
Wherein the intermediate layer material comprises Cr, Zr, V, SiC, Si, Sn, Nb, Ti, In, or Pd. The method according to any one of claims 1 to 3,
Wherein the intermediate layer is formed to a thickness of 1 to 5 占 퐉. 5. The method of claim 4,
Wherein the liner is formed to a thickness of 20 to 100 占 퐉. A method of manufacturing a fuel cladding structure in a sodium cooled high speed furnace,
Preparing a liner having an intermediate layer on its surface;
Preparing an envelope tube,
Molding the liner and the sheath tube by a co-drawing process using a mold for co-drawing molding, and integrally molding the sheath structure;
Lt; / RTI >
Wherein the intermediate layer prevents interference between the sheath tube and the liner due to thermal diffusion resulting from the nuclear power operation operating temperature of the nuclear fuel and increases the adhesion between the sheath tube and the liner, Wherein the material constituting the intermediate layer is deposited in the form of fine particles on the outer circumferential surface of the liner. The method according to claim 6,
Wherein the intermediate layer is formed on the surface of the liner using physical vapor deposition. 8. The method of claim 7,
Wherein the intermediate layer material comprises Cr, Zr, V, SiC, Si, Sn, Nb, Ti, In or Pd. 9. The method according to any one of claims 6 to 8,
Wherein the intermediate layer is formed to a thickness of 1 to 5 占 퐉. 10. The method of claim 9,
Wherein the liner is formed to a thickness of 20 to 100 占 퐉. 11. The method of claim 10,
Wherein said cladding is comprised of ferrite or austenite martensitic steel comprising HT9 and Grade 92. The method of claim < RTI ID = 0.0 > 1, < / RTI >

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