Shielding structure for transportation of Co-60-containing medium-medium-level wastewater

Abstract

The utility model discloses a Co-60 medium-release wastewater transportation shielding structure which comprises an outer shell, a cover plate is arranged at the top of the outer shell, a supporting base is arranged at the bottom of the outer shell, an inner layer which is integrally connected is arranged in the outer shell, frames are arranged between the outer shell and the inner layer respectively, and arc-shaped modules are arranged on the inner sides of the frames. According to the utility model, through the layered shielding design of the housing and the inner layer, the dose rate is accurately controlled; the arc-shaped modules are modularly combined into a lead alloy structure, so that the maintenance cost is reduced; by means of modular splicing of the arc-shaped modules, seam treatment is optimized, and direct leakage is reduced; and the thermal expansion safety margin requirement under the filling rate of 90% is met.

Description

Technical Field

[0001] This utility model relates to the field of wastewater transportation technology, specifically a shielding structure for transporting wastewater containing Co-60. Background Technology

[0002] In the nuclear industry, transport containers for intermediate-level radioactive wastewater containing Co-60 must simultaneously meet the requirements of radiation shielding, structural sealing, and long-term service stability. Currently, the mainstream shielding container designs generally use lead-based materials, but traditional solutions have the following technical bottlenecks:

[0003] 1. Excessive dose leakage: The thickness design of traditional lead shielding structures is unreasonable, resulting in the dose rate at 30cm outside the shield being unable to meet the requirement of ≤2.5μSv / h specified in GB11806-2019;

[0004] 2. Poor material economy: Some solutions use pure lead or composite shielding materials, which are costly and complex to process;

[0005] 3. Difficult to maintain: The integral lead shielding structure cannot be replaced modularly, and there is a high risk of direct leakage at the joints;

[0006] 4. Insufficient adaptability to thermal expansion: When the container filling rate exceeds 90%, liquid expansion can easily lead to seal failure. Utility Model Content

[0007] The purpose of this invention is to provide a shielding structure for transporting wastewater containing Co-60, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a shielding structure for transporting Co-containing radioactive wastewater, comprising an outer shell, a cover plate on the top of the outer shell, a supporting base on the bottom of the outer shell, an integrally connected inner layer inside the outer shell, a frame between the outer shell and the inner layer, and an arc-shaped module on the inner side of the frame.

[0009] Preferably, the outer side of the outer shell has a cylindrical structure and is made of stainless steel to improve the shielding strength of the tank.

[0010] Preferably, the cover plate is detachably connected to the top of the outer shell, and a sealing layer is provided between the outer shell and the cover plate to facilitate the disassembly and assembly of the cover plate and improve the sealing performance of the connection between the outer shell and the cover plate.

[0011] Preferably, the frame is a galvanized steel frame, and the galvanized steel frame and the arc-shaped module are arranged on the outer wall of the inner layer. The shielding effect of the structure is improved by the design of the galvanized steel frame.

[0012] Preferably, the outer shell includes a symmetrical hexagonal grid to enhance impact resistance.

[0013] Preferably, multiple sets of the arc-shaped modules form a lead plate, and the joints of the multiple sets of arc-shaped modules are filled with 45° beveled interlocking and lead welding rods, which facilitates the use of modular splicing to reduce direct leakage paths.

[0014] The present invention provides a shielding structure for transporting Co-containing radioactive wastewater, which has at least the following beneficial effects:

[0015] 1. Precise dose rate control is achieved through a layered shielding design of the outer shell and inner layer;

[0016] 2. The modular combination of arc-shaped modules forms a lead alloy structure, reducing maintenance costs;

[0017] 3. Utilizing the modular splicing of arc-shaped modules optimizes joint treatment and reduces direct leakage;

[0018] 4. Meets the thermal expansion safety margin requirements at a 90% fill rate. Attached Figure Description

[0019] Figure 1 This is a perspective view of the present utility model;

[0020] Figure 2 This is a partial sectional view of the present invention.

[0021] In the diagram: 1. Outer shell; 2. Cover plate; 3. Support base; 4. Frame; 5. Inner layer; 6. Arc-shaped module. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Please see Figure 1-2 The present invention provides an embodiment of a shielding structure for transporting wastewater containing Co-60, comprising an outer shell 1, the outer side of which is cylindrical, and the outer shell 1 is made of stainless steel to improve the shielding strength of the tank. The top of the outer shell 1 is provided with a cover plate 2, and the bottom of the outer shell 1 is provided with a support base 3. The cover plate 2 is detachably connected to the top of the outer shell 1, and a sealing layer is provided between the outer shell 1 and the cover plate 2 to facilitate the disassembly and assembly of the cover plate 2 and improve the sealing performance of the connection between the outer shell 1 and the cover plate 2.

[0024] The outer shell 1 has an integrated inner layer 5 inside, and a frame 4 is provided between the outer shell 1 and the inner layer 5. The inner side of the frame 4 is provided with an arc-shaped module 6. The frame 4 is a galvanized steel frame, and the galvanized steel frame and the arc-shaped module 6 are set on the outer wall of the inner layer 5. The design of the galvanized steel frame improves the shielding effect of the structure. Multiple sets of arc-shaped modules 6 form a lead plate. The joints of multiple sets of arc-shaped modules 6 are filled with 45° beveled interlocking and lead welding rods, which facilitates the use of modular splicing to reduce the direct leakage path.

[0025] Example 1: This wastewater transport shielding structure reduces the lead alloy thickness by 22% compared to the traditional 100mm solution, resulting in an 18% cost saving. It also reduces the seam leakage dose ratio to <5% compared to the traditional solution, which is >30%. The modular design improves the shielding layer replacement efficiency by 70%. The shielding effect under different lead alloy thicknesses was verified by MCNP. When the double-layer shielding structure with a lead alloy thickness of 72mm and a stainless steel thickness of 2mm is used, the dose rate at 0.3m can be reduced to below 2.5μSv / h, with sufficient safety margin.

[0026] Example 2: The activity of the low-level radioactive wastewater tank is ≤4×10⁻⁶. 6 In Bq / L, the dose value at 30cm from the surface of the container is ensured to be less than 2.5μSv / h through lead alloy shielding. The 90L container is designed with a safety margin for wastewater discharge, reserving a 10% 10L buffer to prevent liquid thermal expansion and pressure fluctuations, complying with the requirement of "container filling rate ≤90%" in GB 11806-2019. Zero-leakage transportation is guaranteed.

[0027] Working principle: This wastewater transport shielding structure contains Co-60;

[0028] A layered shielding structure is formed by the layered structure design of the outer shell 1 and the inner layer 5. A lead alloy shielding layer with a thickness of 72 mm and a density of 11.34 g / cm³ is set on the wall of the inner layer 5. The dose attenuation effect is simulated and verified by MCNP software. A cylindrical structure is designed in the outer structure, with an inner diameter of 0.5 m and a height of 0.51 m. The outer diameter of the lead layer is 0.644 m, and the total height is 0.71 m. It forms a closed system with the detachable cover plate 2 and the support base 3. The lead plate is cut into 30 arc-shaped modules, and the joints are filled with 45° beveled interlocking and lead welding rods, thereby optimizing the joint treatment and reducing direct radiation leakage.

[0029] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0030] In the description of this utility model, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly, for example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

Claims

1. A Co-60 containing medium level waste water transport shield structure comprising an outer shell (1), characterised in that: The top of the outer shell (1) is provided with a cover plate (2), the bottom of the outer shell (1) is provided with a support base (3), the interior of the outer shell (1) is provided with an integrated inner layer (5), a frame (4) is provided between the outer shell (1) and the inner layer (5), and an arc-shaped module (6) is provided on the inner side of the frame (4).

2. A Co-60 containing medium-level radioactive waste transport shield structure according to claim 1, characterized in that: The outer side of the outer shell (1) is a cylindrical structure, and the outer shell (1) is made of stainless steel.

3. A Co-60 containing medium-level radioactive waste transport shield structure according to claim 1, characterized in that: The cover plate (2) is detachably connected to the top of the outer shell (1), and a sealing layer is provided between the outer shell (1) and the cover plate (2).

4. The Co-60 containing mid-stream wastewater transport shield structure of claim 1, wherein: The frame (4) is a galvanized steel frame, and the galvanized steel frame and the arc-shaped module (6) are set on the outer wall of the inner layer (5).

5. A Co-60 containing medium level waste water transport shield structure according to claim 1, characterized in that: The outer shell (1) includes a symmetrical hexagonal grid.

6. A Co-60 containing medium-level radioactive waste transport shield structure according to claim 1, characterized in that: Multiple sets of the arc-shaped modules (6) form a lead plate, and the joints of the multiple sets of arc-shaped modules (6) are joined by 45° beveled interlocking and lead welding rods for filling.

Images