Reactor core shielding top cover

Abstract

The utility model discloses a reactor core shielding top cover, which comprises an upper cover and a lower cylinder hermetically connected to an opening of a pressure vessel, the lower opening of the upper cover is hermetically connected with the lower cylinder, and the lower cylinder is of a hollow structure; and the upper cover is provided with a plurality of avoiding holes for reactor measurement instrument columns to pass through. The reactor core shielding top cover disclosed by the utility model is provided with the plurality of avoiding holes, reactor measuring instrument columns can penetrate out of the upper cover through the avoiding holes and are exposed out of the reactor core shielding top cover, the upper cover does not need to be dismounted when a reactor measuring instrument finger sleeve assembly is replaced, and the reactor measuring instrument finger sleeve assembly can be conveniently replaced on the basis of effective radiation protection.

Description

Technical Field

[0001] The utility model relates to the technical field of nuclear power plant reactor maintenance equipment, in particular to a reactor core shielding top cover. Background Art

[0002] During the refueling overhaul of a nuclear power plant reactor, after the reactor pressure vessel cover is opened, a large amount of radioactive substances in the reactor core will leak outwards. During the high water level period of the reactor pool, it can be isolated and absorbed by the boric acid water in the pool. However, when the water level is low, shielding needs to be carried out on the opened reactor pressure vessel so as to isolate and shield radioactive substances to a certain extent.

[0003] At present, a special shielding top cover is used to cover the reactor pressure vessel, which can shield a large amount of radioactive substances in the reactor core, but it is not convenient to replace the reactor core measurement system (RIC) instrumentation assembly. In addition, the shielding ability of the existing shielding top cover still needs to be improved. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is to provide a reactor core shielding top cover.

[0005] The technical solution adopted by the utility model to solve its technical problem is: a reactor core shielding top cover, including an upper cover and a lower cylinder body hermetically connected to the opening of the pressure vessel. The lower opening of the upper cover is hermetically connected to the lower cylinder body, and the lower cylinder body is a hollow structure;

[0006] The upper cover is provided with a plurality of avoidance holes for the reactor instrumentation columns to pass through.

[0007] Preferably, in the reactor core shielding top cover of the utility model, the reactor core shielding top cover further includes a plurality of protective covers, and the protective covers are arranged above the avoidance holes and are detachably connected to the upper cover to cover the reactor instrumentation columns.

[0008] Preferably, in the reactor core shielding top cover of the utility model, the upper part of the upper cover is recessed inwards to form a plurality of avoidance grooves, and each avoidance groove is communicated with at least one avoidance hole;

[0009] The protective cover is arranged above the avoidance groove and is detachably connected to the opening edge of the avoidance groove.

[0010] Preferably, in the reactor core shielding top cover of the utility model, a first shielding layer is encapsulated in the side wall of the protective cover.

[0011] Preferably, in the reactor core shielding top cover of the present utility model, the lower cylinder body includes an upper flange, an inner cylinder body, a second shielding layer, an outer cylinder body and a lower flange. The lower flange is arranged at the bottom of the second shielding layer and is respectively connected to the inner cylinder body, the second shielding layer and the outer cylinder body; the upper flange is arranged at the top of the second shielding layer and is respectively connected to the inner cylinder body and the outer cylinder body;

[0012] A gap is left between the second shielding layer and the upper flange.

[0013] Preferably, in the reactor core shielding top cover of the present utility model, the gap between the second shielding layer and the upper flange is 7 mm to 10 mm.

[0014] Preferably, in the reactor core shielding top cover of the present utility model, the second shielding layer is a multi-layer lead plate, and the gap is filled with lead water;

[0015] The thickness of the second shielding layer is 35 mm - 45 mm.

[0016] Preferably, in the reactor core shielding top cover of the present utility model, the reactor core shielding top cover further includes a positioning member and a shielding cover. The positioning member fixedly connects the lower flange to the pressure vessel, and the shielding cover covers the positioning member;

[0017] A third shielding layer is encapsulated in the side wall of the shielding cover.

[0018] Preferably, in the reactor core shielding top cover of the present utility model, the reactor core shielding top cover further includes a ladder. The ladder is fixedly connected to the upper cover and / or the lower cylinder body and extends along the axial direction of the lower cylinder body;

[0019] A protective cage is arranged outside the ladder.

[0020] Preferably, in the reactor core shielding top cover of the present utility model, the reactor core shielding top cover further includes a lifting assembly and a plurality of guiding mechanisms that are positioned and matched with guiding columns. The plurality of guiding mechanisms are fixedly connected to the outer wall of the lower cylinder body, and the lifting assembly is fixedly connected to the upper cover.

[0021] By implementing the present utility model, the following beneficial effects are achieved:

[0022] The reactor core shielding top cover of the present utility model includes an upper cover and a lower cylinder body hermetically connected to the opening of the pressure vessel. The lower opening of the upper cover is hermetically connected to the lower cylinder body, and the lower cylinder body is a hollow structure; the upper cover is provided with a plurality of avoidance holes for the reactor measurement instrument columns to pass through. The reactor core shielding top cover is provided with a plurality of avoidance holes, and the reactor measurement instrument columns can pass through the avoidance holes and protrude out of the upper cover. When replacing the finger sleeve assembly of the reactor measurement instrument, it is not necessary to remove the upper cover, which facilitates the replacement of the finger sleeve assembly of the reactor measurement instrument on the basis of effective radiation protection. Description of the Drawings

[0023] The present utility model will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0024] Figure 1 is a schematic structural diagram of the reactor core shielding top cover according to an embodiment of the present utility model;

[0025] Figure 2 is Figure 1 a sectional view of the reactor core shielding top cover;

[0026] Figure 3 is Figure 1 a partial sectional view of the lower cylinder body. Detailed Embodiments

[0027] In order to have a clearer understanding of the technical features, objectives, and effects of the present utility model, the detailed embodiments of the present utility model will now be described with reference to the drawings.

[0028] It should be noted that, without conflict, the embodiments in the present utility model and the features in the embodiments may be combined with each other.

[0029] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise specified, the meaning of "a plurality" is two or more.

[0030] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "linkage" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a chemical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0031] See Figures 1 to 3 , an embodiment of the present utility model discloses a reactor core shielding top cover, which is used for temporarily shielding the radiation in the reactor core after opening the top cover of the pressure vessel 100 of the reactor during the refueling overhaul of the reactor.

[0032] The reactor core shielding top cover includes an upper cover 1 and a lower cylinder body 2 hermetically connected to the opening of the pressure vessel 100. The lower opening of the upper cover 1 is hermetically connected to the lower cylinder body 2, and the lower cylinder body 2 is a hollow structure. The upper cover 1 is provided with a plurality of avoidance holes 11 for the reactor measurement instrument columns to pass through. Preferably, the avoidance holes 11 are circular holes with a diameter slightly larger than the diameter of the reactor measurement instrument columns. The reactor measurement instrument columns extend along the axial direction of the pressure vessel 100, that is, along the axial direction of the upper cover 1, and the avoidance holes 11 are generally provided on the top wall of the upper cover 1. The reactor measurement instrument columns can pass through the avoidance holes 11 and extend out of the upper cover 1, exposing outside the reactor core shielding top cover. When replacing the reactor measurement instrument finger sleeve assembly later, it is not necessary to remove the upper cover 1, nor to enter the inside of the cover body, which is convenient for replacing the reactor measurement instrument finger sleeve assembly on the basis of effective radiation protection. Generally, the reactor measurement instrument finger sleeve assembly is installed on the upper part of the reactor measurement instrument column and is fixedly installed on the reactor core through the reactor measurement instrument column to monitor the situation of the reactor core in real time.

[0033] Furthermore, as Figure 1 shown, the reactor core shielding top cover further includes a plurality of protective covers 3. The protective covers 3 are arranged above the avoidance holes 11 and are detachably connected to the upper cover 1 to cover the reactor measurement instrument columns. Preferably, one protective cover 3 can cover one or more reactor measurement instrument columns. In this embodiment, the number of the protective covers 3 is four, and one protective cover 3 can cover three reactor measurement instrument columns to shield the reactor measurement instrument columns when there is no operation and prevent radiation leakage. When disassembling and assembling the reactor measurement instrument finger sleeve assembly, it is necessary to remove the protective covers 3 first and then perform subsequent operations.

[0034] Preferably, in some embodiments, in order to enhance the shielding effect of the protective covers 3, a first shielding layer is encapsulated in the side wall of the protective covers 3, which is not shown in the figure. The first shielding layer can include one or more lead plates.

[0035] Furthermore, as Figure 1 and Figure 2As shown in the figure, in order to enhance the shielding effect of the upper cover 1, while maintaining the axial length of the upper cover 1, the upper part of the upper cover 1 is recessed inward to form a plurality of avoidance grooves 12, and each avoidance groove 12 communicates with at least one avoidance hole 11. The protective cover 3 is arranged above the avoidance groove 12 and is detachably connected to the opening edge of the avoidance groove 12. This can enable the pile measurement instrument column to pass through the upper cover 1 through the avoidance hole 11, without restricting the height of other parts of the upper cover 1, facilitating the replacement of the pile measurement instrument finger sleeve assembly while maintaining the existing protection effect. Preferably, one avoidance groove 12 can communicate with one avoidance hole 11, or one avoidance groove 12 can communicate with multiple avoidance holes 11. In this embodiment, the number of avoidance grooves 12 is 4, and one avoidance groove 12 can communicate with three avoidance holes 11. A protective cover 3 is correspondingly arranged on each avoidance groove 12 to shield the pile measurement instrument column when there is no operation and prevent radiation from leaking out.

[0036] Furthermore, as Figure 3 shown, in order to enhance the shielding effect of the lower cylinder body 2, the lower cylinder body 2 includes an upper flange 21, an inner cylinder body 22, a second shielding layer 23, an outer cylinder body 24 and a lower flange 25. The lower flange 25 is arranged at the bottom of the second shielding layer 23 and is respectively connected to the inner cylinder body 22, the second shielding layer 23 and the outer cylinder body 24. The upper flange 21 is arranged at the top of the second shielding layer 23 and is respectively connected to the inner cylinder body 22 and the outer cylinder body 24. A gap is left between the second shielding layer 23 and the upper flange 21. Preferably, the second shielding layer 23 is multiple layers of lead plates with a total thickness of 35 mm - 45 mm. The gap between the second shielding layer 23 and the upper flange 21 is 7 mm to 10 mm, and the gap is filled with lead water. This can eliminate the bulging situation caused by the compression and extension of the lead plates and improve the wrapability of the lead plates.

[0037] Furthermore, as Figure 1 shown, in order to fixedly connect the lower cylinder body 2 and the opening of the pressure vessel 100, prevent radiation leakage and enhance the shielding effect, the reactor core shielding top cover further includes a positioning member and a shielding cover 4. The positioning member fixedly connects the lower flange 25 and the pressure vessel 100, and the shielding cover 4 covers the positioning member. A third shielding layer is encapsulated in the side wall of the shielding cover 4. Preferably, the third shielding layer can include one or more layers of lead plates. This can enhance the shielding effect of the shielding cover 4 and reduce the risk of radiation material leakage at the shielding boundary. Among them, the positioning member and the third shielding layer are not shown in the figure.

[0038] Furthermore, as Figure 1 and Figure 2As shown in the figure, for the convenience of maintenance operations, such as the replacement of the pile measurement instrument finger sleeve assembly, the reactor core shielding top cover further includes a ladder 5. The ladder 5 is fixedly connected to the upper cover 1 and / or the lower cylinder 2 and extends along the axial direction of the lower cylinder 2. A protective cage 6 is provided outside the ladder 5. Preferably, the ladder 5 is fixedly connected to the upper cover 1 and the lower cylinder 2. The ladder 5 and the protective cage 6 can be hung by gravity, which is convenient for disassembly and assembly, and improves the replacement efficiency and safety of the pile measurement instrument finger sleeve assembly.

[0039] Furthermore, as Figure 1 and Figure 2 shown in the figure, for the convenience of the installation and disassembly of the reactor core shielding top cover, the reactor core shielding top cover further includes a lifting assembly 7 and a number of guiding mechanisms 8 that are positioned and matched with the guiding columns 200. The number of guiding mechanisms 8 is fixedly connected to the outer wall of the lower cylinder 2, and the lifting assembly 7 is fixedly connected to the upper cover 1. Preferably, there are at least three guiding mechanisms 8, and the position of each guiding mechanism 8 corresponds to that of a guiding column 200. The three guiding mechanisms 8 are respectively sleeved on the guiding columns 200 to achieve positioning.

[0040] The lifting assembly 7 includes a lifting beam 71, a main lifting hole assembly 72, and two lifting rings 73. The lifting beam 71 is cross-welded on the top of the upper cover 1, and the intersection point of the lifting beam 71 is the geometric center point of the reactor core shielding top cover. The main lifting hole assembly 72 is welded at the geometric center point and is used for the lifting of the reactor core shielding top cover in the nuclear island. The two lifting rings 73 are arranged on the lifting beam 71 on both sides of the main lifting hole assembly 72 and are centrally symmetrically arranged with the lifting holes as the symmetry points. The two lifting rings 73 are used for the lifting of the reactor core shielding top cover during assembly and transportation.

[0041] By implementing the present utility model, the following beneficial effects are achieved:

[0042] The reactor core shielding top cover of the present utility model is provided with a number of avoidance holes 11. The pile measurement instrument column can pass through the avoidance holes 11 and penetrate out of the upper cover 1, exposing it outside the reactor core shielding top cover. When replacing the pile measurement instrument finger sleeve assembly, it is not necessary to remove the upper cover 1, which is convenient for the replacement of the pile measurement instrument finger sleeve assembly on the basis of effective radiation protection.

[0043] It is understandable that the above embodiments only represent the preferred embodiments of the present utility model, and the description thereof is relatively specific and detailed. However, it should not be construed as a limitation on the scope of the patent of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, the above embodiments or technical features can be freely combined, and several deformations and improvements can also be made. These all belong to the protection scope of the present utility model, that is, the embodiments described in "in some embodiments" can be freely combined with any of the above or below embodiments. Therefore, all equivalent transformations and modifications made to the scope of the claims of the present utility model shall fall within the scope covered by the claims of the present utility model.

Claims

1. A reactor core shielding top cover, characterized in that: It comprises an upper cover (1) and a lower cylinder (2) sealed on the opening of a pressure container (100), the lower opening of the upper cover (1) is tightly connected to the lower cylinder (2), and the lower cylinder (2) is a hollow structure; The upper cover (1) is provided with a plurality of avoidance holes (11) for stacking measuring instrument columns to pass through.

2. The reactor core shielding top cover according to claim 1, characterized in that: The reactor core shielding top cover also includes a plurality of protective covers (3), wherein the protective covers (3) are arranged above the avoidance holes (11) and are detachably connected to the upper cover (1) to cover the stack instrument columns.

3. The reactor core shielding top cover according to claim 2, characterized in that: The upper portion of the upper cover (1) is recessed inward to form a plurality of avoidance grooves (12), and each of the avoidance grooves (12) is connected to at least one of the avoidance holes (11); The protective cover (3) is arranged above the avoidance groove (12) and is detachably connected to the opening edge of the avoidance groove (12).

4. The reactor core shielding top cover according to claim 2, characterized in that: A first shielding layer is encapsulated in the side wall of the protective cover (3).

5. The reactor core shielding top cover according to claim 1, characterized in that: The lower cylinder (2) comprises an upper flange (21), an inner cylinder (22), a second shielding layer (23), an outer cylinder (24) and a lower flange (25); the lower flange (25) is arranged at the bottom of the second shielding layer (23) and is respectively connected to the inner cylinder (22), the second shielding layer (23) and the outer cylinder (24); the upper flange (21) is arranged at the top of the second shielding layer (23) and is respectively connected to the inner cylinder (22) and the outer cylinder (24); A gap is left between the second shielding layer (23) and the upper flange (21).

6. The reactor core shielding top cover according to claim 5, characterized in that: The gap between the second shielding layer (23) and the upper flange (21) is 7 mm to 10 mm.

7. The reactor core shielding top cover according to claim 5, characterized in that: The second shielding layer (23) is a multi-layer lead plate, and the gap is filled with lead water; The thickness of the second shielding layer (23) is 35 mm-45 mm.

8. The reactor core shielding top cover according to claim 5, characterized in that: The reactor core shielding top cover further comprises a positioning member and a shielding cover (4), wherein the positioning member fixedly connects the lower flange (25) to the pressure vessel (100), and the shielding cover (4) covers the positioning member; A third shielding layer is encapsulated in the side wall of the shielding cover (4).

9. The reactor core shielding top cover according to any one of claims 1 to 8, characterized in that: The reactor core shielding top cover further comprises a ladder (5), wherein the ladder (5) is connected and fixed to the upper cover (1) and / or the lower cylinder (2), and extends along the axial direction of the lower cylinder (2); The ladder (5) is provided with a protective cage (6) outside.

10. The reactor core shielding top cover according to any one of claims 1 to 8, characterized in that: The reactor core shielding top cover also includes a hanging assembly (7) and a plurality of guide mechanisms (8) positioned and matched with the guide columns (200); the plurality of guide mechanisms (8) are fixedly connected to the outer wall of the lower cylinder (2); and the hanging assembly (7) is fixedly connected to the upper cover (1).

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