TW200527449A - Metal gasket and manufacturing method therefor, and radioactive substance containment vessel - Google Patents

Abstract

To facilitate drainage of water inside a metal gasket. In this metal gasket 20, the radial inner side of an inner cover 40 covering a coil spring 30 is formed with a plurality of drainage holes 101. The inner cover 40 is held by an outer cover 50, and the double rings having different hoop diameters are integrated by the outer cover 50. The drainage hole 101 facilitates the drainage of the water collecting inside the metal gasket 20. The drainage hole 101 is positioned near the center in the seal thickness direction such that approach to a seal face 90 is avoided.

Description

200527449 (1) Description of the invention: [Technical field to which the invention belongs] The present invention relates to a sealed metal gasket used for a cylinder or the like that can house a recycled fuel assembly, a method for manufacturing the same, and a container for storing radioactive materials. [Prior art] At the end of nuclear fuel recovery, the nuclear fuel assembly system that has ended combustion is referred to as a recovered fuel assembly. The recycled fuel assembly contains highly radioactive substances such as "," which must be thermally cooled, so it can be extinguished for a long time in the cooling tank of a nuclear power plant. After that, it can be stored in a cylinder as a shielding container and transported by rails, It is stored in the processing facility. Since the cylinder contains high-level radioactive substances, it is necessary to pay close attention to the seal of the cylinder during the storage period of 40 to 60 years. Figure 5 shows the structure of the conventional cylinder Figure 6 is an enlarged view of a part of the cylinder shown in Figure 6. The cylinder 500 is composed of the following components: a stainless steel or carbon steel cylinder body 501; and an outer cylinder 502, which is used to form a cylinder. Outside; polymer resin 503, which contains hydrogen that can be filled between the cylinder body 50m and the outer cylinder 502; bottom plate 505, which is fused to the ^ part of the cylinder body 50m, and sealed Resin made of resin 504; and main cover 507 and sub cover 508, which are provided on the flange portion 506 which is integrated with the cylindrical body 501 by welding. The basket 513 for storing the recovered fuel assembly can be arranged In the cavity 509 of the cylindrical body 501. As shown in the figure: 510 and 511 fix the main cover 507 and the sub cover 508 to the flange portion 506, and seal the resin 512 in the sub cover 508. The basket 513 is a plural number formed by the composite material of (B) and Shao. unit

O: \ 90 \ 90842.DOC 200527449. The cavity 500 of the cylinder 500 is filled with helium in a negative pressure state. On the other hand, a positive pressure is formed in the gap between the main shaft 507 and the sub cover 508, and a pressure barrier is formed between the inside and the outside of the cylinder 500. In addition, the auxiliary shaft 508 is provided with a hole 5 丨 4 for detecting the pressure in the space between the lids, and a pressure sensor 515 is provided at the exit of the hole 514. The main cover 507 is provided with a valve 516 for replacing the gas in the cylinder 500. The valve 516 is covered by a valve cover 517. The seal between the main cover 507 and the cylindrical body 501, and the sub cover 508 and the cylindrical body 501, from the viewpoint of maintaining the sealing function for a long time, can make the appliance heat-resistant, corrosion-resistant, and durable. High metal washers 518, 519. Fig. 7 is an enlarged view showing a metal gasket not used for sealing a cylinder and a sealing part of the cylinder. The sealing portions between the main cover 507 and the cylindrical body 501 and between the sub cover 508 and the cylindrical body 501 have the same sealing structure. The gasket groove 525 is formed by machining, and the metal gaskets 518 and 519 used are of a double ring construction. The structure of the metal gaskets 518 and 519 is made of a corrosion-resistant or high-temperature oxidized inconel (trade name: nickel-based alloy). The spiral spring 521 is covered by an inner shell 522, which is also made of inconel. The aluminum casing 523 covers the inner and outer wheels. Fig. 7 (The hook system shows the state of the metal washer 518 (5 19) before use. When the metal washer 518 (519) fixes the auxiliary cover 5⑽ and the like and the cylindrical body 501 and the like, as shown in FIG. 7 (b), The force can deform and exert a sealing function. The washer groove 525 is fixed by using bolt holes provided in the housing 523. In the aforementioned metal washers 518 and 519, for example, there are many examples of the use of nuclear power cylinders. Made by Kawei Industry Co., Ltd.

O: \ 90 \ 90842.DOC 200527449 7th night "or" ~ y77 夕 only_Kouji "made by CEFILAC, France. In addition, the structure of the metal gasket to ensure tightness is a single ring type = a gasket, and A metal washer formed by forming a solid lubricating material between the 523 and the inner shell 522 to suppress leakage is disclosed in Patent Document 1. [Patent Document] Bento, Fair No. 5-75154 pi, Figure !, Figure 2 However, When the recovered fuel assembly is stored in the cylinder 500, the operation is performed in a hoop. After the recovered fuel assembly is stored, the internal water must be drained by vacuum drying. However, the above metal gasket has a double structure :: utilization The outer ring holds the coiled coil spring, so water accumulates in the inner and outer rings, and there is a problem that it is difficult to drain the water when the water is drained. On the other hand, the 5 Hai metal gasket is wound around the coiled spring with a plate-shaped inner shell. Therefore, it is necessary to wind the opening part to the outside for winding operation. In this way, in order to easily drain the water inside, it is difficult to make the two inner shell openings face inward. Head The purpose is to provide a metal gasket capable of removing moisture from the metal gasket and exhibiting sufficient sealing properties over a long period of time, a method for manufacturing the same, and a storage container for a radioactive substance. SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the metal of the present invention The gasket is interposed between the cylindrical body for storing the radioactive material storage container of the recovered fuel assembly and the cover installed in the cavity opening of the cylindrical body to maintain the seal in the cavity. In the metal gasket, It is characterized in that the metal washer has a ring-shaped spiral. A spring, an inner shell for covering the coil spring, and an outer shell for covering the inner shell, the inner shell is provided with a drainage hole. The feature is preferably that the inner shell precedes the outer shell. Trail

O: \ 90 \ 90842.DOC 200527449 The exposure side is exposed, and drainage holes are provided on the exposed radial side. ^ Use the drainage hole 'to drain the water enclosed in the inner shell to the outside. In addition, it is preferable that the radial direction is at least 45 degrees with respect to the radial J-series soil. Beyond this range temple, the water s stays between the sealing surface and the Xibu shell Γ eight and is difficult to dry. The shape of the drain hole may be circular or rectangular. Secondly, the invention's metal plutonium ring is located between the cylindrical body of the radioactive material storage container and the plutonium installed in the cavity opening to maintain the seal in the cavity. In the metal gasket, its characteristics The metal washer is formed by concentrically forming two ring-shaped spiral elastic springs of different hoop diameters and covering the above-mentioned coil spring to form a double ring. In addition, the inner shell is covered with the outer shell and the outer shell is used to connect between the rings for integration. A drainage hole is provided on the radial side of the inner shell of the metal washer. In this way, the inner shell of the 纟 is provided with drainage holes, and the water in the inner shell can be effectively discharged to the outside. Secondly, the invented metal gasket is between the cylindrical body for storing the radioactive material storage container of the recovered fuel assembly and the cover of the cavity opening of the cylindrical body to maintain the seal in the cavity. This metal ring is characterized by the structure of a metal washer formed by forming a plate into a ring shape with a circular cross section, and forming a spring so that its ends overlap each other. A housing is provided in the spring, and the metal The gasket is provided with a drainage hole. In the present invention, the plate is formed so that the cross section is circular, and the ring is formed as a spring. Next, a casing is provided outside the spring. Since the spring has a circular cross-section, it is easy for water to enter the interior. Therefore, the water can be easily drained out by perforating the drainage hole in a metal washer. Secondly, the method of manufacturing the metal gasket of the invention is characterized in that

O: \ 90 \ 90842.DOC -10- 200527449 The drainage hole is perforated, and the sheet is wound on the spiral elastic cyan surface forming a ring ’to form an inner shell from the sheet, and then the outer shell is wound around the shell. The radioactive material storage container of the second invention has the advantage that the above-mentioned metal gasket is interposed between a cylindrical body for receiving a cylinder of the recovered fuel assembly and a cover installed in the cavity opening of the cylindrical body. [Embodiment] Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment. In addition, the constituent elements of the following embodiments may include those that are easily assumed by the operator or those that are substantially the same. In addition, the use of the metal gasket of the present invention is not particularly limited. For example, it can be used in a cylinder or a sealed portion of an atomic furnace storage container. In addition, the metal gasket is particularly suitable for applications where the sealing performance can be maintained in units of decades in a comparative South temperature environment, and among them, a cylinder used for storing and collecting the recovered fuel assembly and storing for a long time is the best. (Embodiment 1) FIG. 1 is an explanatory view showing a sealing structure of a cylinder according to Embodiment 1 of the present invention. Fig. 2 is a sectional view showing a metal washer according to a first embodiment of the present invention. The cylindrical bifurcation seal structure 10 is characterized in that the inner shell is provided with a drainage hole 丨 〇 丨. In addition, the metal washer 20 described next is a so-called double-ring type, which arranges two coil springs 30a and 30b of different hoop diameters Df in a concentric shape, and then uses the peripheral 50-while covering both, Combination. However, the metal washer that can be used in the present invention is not limited to this type, and as shown in FIG. 2 (b), a single-ring type metal washer 20 'or (c) may be included as a flat metal washer on the upper portion of the housing 50. As shown in FIG. 1, the sealing structure 10 is provided on, for example, a sub-cover 508 of a cylinder 500.

O: \ 90 \ 90842.DOC -11-200527449 and the flange portion of the cylindrical body 501. It is needless to say that the seal structure and the metal gasket of the present invention (the same shall apply hereinafter) between the cylinder main cover and the cylinder body 501. As shown in FIG. 2, the metal washer 20 has a structure in which the inner coil 40 'is covered with an annular coil spring 30, and the inner and outer wheels are integrated with the outer shell 50 and covered. A drain hole 101 is perforated on a radially inner side of the inner case 40 exposed from the outer case 50 (the inner peripheral ring and the inner peripheral ring are referred to as an inner side). In addition, the drainage hole 101 is perforated at a position that does not interfere with the casing 50. In this way, it is only necessary to provide the drainage hole 101 in the inner shell 40. In addition, the inner shell 40 is perforated with the drainage hole 101, and the inner shell 40 is formed into a ring shape to be wound around the coil springs 30 and 30b, and the coil springs 30a and 30b are covered. In addition, the hoop diameter Df of the metal washer 20 (the distance from the center c of the cylindrical body 501 to the metal washer 20) is about 2 m, and the cross-sectional diameters D of the inner ring 70 and the outer ring 80 are respectively 5 · 5. The thickness of the outer shell 50 is about 0.4 mm, and the thickness of the inner 40 is 0.2 mm. The shell 50 can be made of soft shell metals such as aluminum, silver, copper and nickel to ensure sealing performance. In addition, for the inner case 40 and the helical cymbal spring 30, nickel-based alloys such as corrosion-resistant or high-temperature oxidation-resistant nickel-nickel alloys (registered trademark) or stainless steel can be used to maintain elasticity under high-temperature environments. In order to further improve the durability at high temperatures, use of ten or more contents of C0 is possible. For the auxiliary cover 508 or main cover and the cylindrical body 501, stainless steel or carbon steel can be used to shield radiation and maintain mechanical strength. On the other hand, in the case 50 of the metal washer 20, a soft metal such as silver or silver is used in order to exert the sealing performance. In this way, through the contact of dissimilar metals, a potential difference is generated between the two, forming a metal gasket 20 that causes electrolytic corrosion and causes the seal to leak.

O: \ 90 \ 90842.DOC -12- 200527449. As such, in terms of the material of the cylinder sub-cover 508 or the cylinder body 501, molybdenum-containing SUS3 17 or SUS625 is used to prevent electrolytic rot. In addition, since SUS3 17 or SUS625 has good weldability, it is used as a cylinder for many welded parts. In addition to SUS317 or SUS625, SUS3 14, SUS316, SUS3 26, SUS3 45, etc. can also be used. Furthermore, with regard to the Tian 1J 盍 508 and the round body 501, even if SUS317 or the like is not used, a sealing surface 90 (not shown) can be formed by diversifying the same material. Alternatively, as the case 50, aluminum having a corrosion potential higher than SUS3174SUS625 containing molybdenum used for the material of the cylinder sub-cover 508 or the cylinder body 501 may be used. In this way, since the outer casing 50 of the metal washer 20 which is easy to exchange is easier than the auxiliary cover 508 or the cylindrical body 5 (1), the auxiliary cover 508 or the cylindrical body 501 can be protected from electrolytic corrosion. Next, a description will be given of a ring-shaped spiral spring 30 used for the metal washer 20. Fig. 3 is an explanatory view showing a spiral spring of a metal ring according to an embodiment of the present invention. As shown in the figure, the Spiral Projection Department 30 uses chrome (iron) as a base alloy (registered trademark) or non-recorded steel or two ("registered trademark") which can withstand higher temperatures. Rolled up and made. If there is a gap between the lines on the t side, "When the metal gasket 20 is squeezed for sealing," the door cannot be promoted with equal force ... 0 and the housing 5 (see Figure 2), long The expected sealing performance cannot be exhibited during use. In general, the metal gasket 20 (the one with a wide linear diameter d from Lai Zhao uses a spiral elastic cyanine 3.) has a high rigidity in order to obtain the sealing pressure. .Because the linear control d of the spiral spring 30 such as the ancient green l / is too wide, that is, it is difficult to form a straight line, so the coil of the spiral spring 3. The expansion of the coil _ will also be expanded by two =

O: \ 90 \ 90842.DOC '13-200527449 The cross-section of the metal washer 20 is required to have a high sealing pressure. In addition, the face diameter D is lower than the sealing pressure

The same applies in the direction of applied force). Next, the drain hole 101 will be described. Inside the hoop, the recovered fuel is collected by vacuum drying, and the inside of the metal ring 20 is housed in the cylinder 500, and the water is taken out from the hoop. At this time, the coil spring 30 is immersed in water, and when the inner casing 40 is opened for 40 seconds, the inside of the inner casing 3 is easily immersed in water. In addition, before the inner side is left open, water will enter through the space between the outer shell 50 and the inner shell 40 and accumulate inside the inner shell 3 Ob. In addition, water also infiltrates from the merging surface of the outer shell 50 and the inner shell 40 and accumulates inside. When water inside the metal washer 20 is drained from the cylinder 500, the water is drained from the drain hole 101 to the outside. In addition, since the inner case 40a having an opening 40s on the inner side drains the water from the opening 40s, a drain hole is not particularly required. For example, the opening 40 s is located relatively above (near the connecting part 50 a of the housing 50), and it must be formed in a shape that is easy to accumulate water (illustration omitted). In addition, at the merging surface between the outer shell 50 and the inner shell 40, there must be a hole 10 0 Γ in order to discharge the accumulated water. Next, when manufacturing the metal washer 20, first, when the drain holes 101 and 10 r are perforated with the coil spring 30 rolled up by the inner case 40, care must be taken not to process the coil spring 30. To this end, the inner shell 40 is first wound around the coil spring 30, the drainage hole 101 is first perforated, and then the coil spring 30 is wound. In this way, the perforating operation can be easily performed without damaging the coil spring 30. In addition, in the above-mentioned embodiment, the hole position of the inner case 40 faces the inside in the radial direction.

O: \ 90 \ 90842.DOC -14- 200527449 (the center line L with two rings) is perforated. If it is inclined downward, it will make the opening ineffective when it meets the sealing surface. Specifically, it is preferable that the position of the drainage hole ιι is within ± 45 degrees from the center of the line L in the inner direction. (Second Embodiment) Fig. 4 is a sectional view showing a metal washer according to a second embodiment of the present invention. As shown in FIG. 4 (a), the metal washer is configured to form the inner shell 200 into a ring shape, and the two inner shells 210 having different hoop diameters are arranged concentrically. In addition, the two are covered and combined with each other by the outer shell, forming a double ring as a whole. Furthermore, the metal gasket 200 that can be used in the present invention is not limited to this type, as shown in FIG. 4 (b), it can also be used in A so-called single-ring type metal washer 250 covered with an inner shell 210 and an outer shell 200. The outer shell 220 can be made of soft metals such as aluminum, silver, copper, and nickel to ensure sealing performance. In addition, the inner shell 21 is used for Nickel-based alloys such as Inconel (registered trademark), which are resistant to corrosion or high-temperature oxidation, can maintain elasticity in high-temperature environments. To further improve high-temperature durability, Co can be used. (Registered trademark), etc. The inner shell 21 is formed into a ring shape to partially overlap, and the overlapping portion 210s is slid by compression during sealing to reduce the diameter of the inner shell 2H as a whole. That is, since only the inner shell is reduced Straight 2 in 2O does not enlarge the contact surface of the inner shell 210, so that it can be reliably sealed. Inside the two inner shells 210, the majority of the drainage holes 23 ° and -30 are made in the circumferential direction. 5Hai drainage holes 230, 230, which will invade the interior Those discharged to the outside will be located in the middle of the thickness direction (height direction in the figure) from the middle of the direction &. For example, when it is placed below, it will interfere with the casing%, so the casing 50 must be perforated. In addition, it is located near the sealing surface

O: \ 90 \ 90842.DOC -15- 200527449, water easily penetrates between the shell 50 and the sealing surface, and it is difficult to dehydrate. Specifically, it is preferable that the position of the drainage hole 21 0 is within ± 45 degrees from the center line L in the meridional direction. On the other hand, since the inner shell 21a on the small-diameter side has the overlapping portion 21 Os located inside the metal washer, it is necessary to slide the overlapping portion 210s with a sealed compression, and perforate the drainage hole 23o at a position not hidden. The metallic ring 250 shown in Fig. 4 (b) is formed into a ring shape by laminating the plate-shaped inner case 210 and the outer case 220. Next, the drainage hole 230 is perforated at approximately the center in the thickness direction. At this time, since the inner case 210 is not exposed to the outside, the drain hole 230 is perforated to penetrate both the inner case 210 and the outer case 220. In the case of a separate plate of the inner shell and the outer shell ', the drainage hole 2 30 is perforated on the opposite side of the heavy surface 2 10 s. [Effects of the Invention] As described above, according to the present invention, the moisture in the metal ring can be removed, and sufficient sealing performance can be exhibited over a long period of time. [Brief description of the drawings] Fig. 1 is an explanatory view showing a sealing structure of a cylinder according to a first embodiment of the present invention. Figs. 2 (a) and 2 (b) are cross-sectional views showing a metal cymbal ring according to the first embodiment of the present invention. 3 (a) and 3 (b) are explanatory views showing a coil spring of a metal washer according to the first embodiment of the present invention. 4 (a) and 4 (b) are sectional views showing a metal washer according to a second embodiment of the present invention.

O: \ 90 \ 90842.DOC -16- 200527449 Fig. 5 is a sectional view showing the structure of a conventional cylinder. Fig. 6 is an enlarged view of a part of the cylinder shown in Fig. 5. 7 (a) and 7 (b) are enlarged views showing a metal gasket used for sealing a cylinder and a sealing portion of the cylinder. [Illustration of Symbols in the Drawings] 10 Seal Structure 20 Metal Washer 30 Coil Spring 40 Inner Shell 50 Outer Shell 90 Sealing Surface 101 Drain Hole O: \ 90 \ 90842.DOC -17-

Claims (1)

200527449 Scope of patent application: 1. A metal washer that maintains a cavity between a cylindrical body containing a radioactive material storage container for recovered fuel assembly and a cover installed in the cavity opening of the cylindrical body The inner sealer is characterized in that: the metal washer has an annular coil spring, an inner shell covering the coil spring, and an outer shell covering the inner shell; and the inner shell is provided with a drainage hole. 2. A metal gasket, which is located between a cylinder body that houses a radioactive material storage container for recovered fuel assembly and a cover that is installed in the cavity opening of the cylinder body to maintain the seal in the cavity. The metal washer has a ring coil spring, an inner shell covering the coil spring, and an outer shell covering the inner shell; and the inner shell is exposed on a radial direction side of the outer shell, and a drainage hole is provided on the exposed radial direction side. 3. A metal gasket, which is located between a cylinder body that houses a radioactive material storage container for recovered fuel assembly and a cover that is installed in the cavity opening of the cylinder body to maintain the seal in the cavity. The metal washer arranges two ring-shaped coil springs with different hoop diameters in a concentric shape and covers the coil spring to form a double ring. The inner shell is covered with an outer shell and the outer shell is used to connect between the rings and integrated; and The outer shell is an inner shell inside the metal gasket exposed from the outer shell, and a drainage hole is provided on a radial side of the exposed inner shell. 4. A metal washer, which is interposed between a cylindrical body of a radioactive material storage container containing a recovered fuel assembly and a cavity installed in the cylindrical body. O: \ 90 \ 90842.DOC 200527449 The sealer in the cavity is characterized in that the metal vow ring is formed by forming the plate into a ring shape and having a circular cross section, and the ends thereof are mutually heavy with each other &gt; The structure of the shell is provided with drainage holes in the metal gasket. 5. A method for manufacturing a cymbal, which is characterized in that the plate is drained and drained. 3 The d plate is wound on the surface of the coil spring forming a ring, and the plate forms an inner shell, and then the inner shell is wound around the outer shell. Species: genus ring <manufacturing method 'is characterized in that a drainage hole is formed in the plate, and the plate is wound on the surface of the spiral elastic cyanine which forms a ring, and the plate constitutes an inner shell. The drain hole is wound around the casing. 7. The radioactive material storage container has the advantage that the metal gasket of any one of the above-mentioned patent scopes 1 to 4 is between the recovered fuel assembly (the cylindrical body of the container and the empty space installed in the cylindrical body). Between the openings of the cavity. O: \ 90 \ 90842.DOC