Floating nuclear power platform and radiation shielding system thereof

Abstract

The invention provides a floating nuclear power platform and a radiation shielding system thereof. The radiation shielding system comprises a primary shielding structure, a combined shielding structure and a containment shielding structure, the primary shielding structure covers the outer side of a reactor pressure vessel to perform primary shielding on the reactor pressure vessel, the combined shielding structure sleeves a loop pipeline and accessory equipment thereof, and the containment shielding structure is arranged in the containment structure; the primary shielding structure comprises a first heat preservation layer wrapping the outer side of the pressure vessel shell, a shielding water tank covering the first heat preservation layer and a shielding material layer covering the outer side of the shielding water tank, and the shielding water tank is hollow to contain water. The combined shielding structure comprises a high-density alloy layer and a second thermal insulation layer; the high-density alloy layer is sleeved outside the loop pipeline and accessory equipment thereof; the second thermal insulation layer is sleeved outside the high-density alloy layer; the containment shielding structure comprises a lead plate, a polyethylene plate layer, a boron-containing polyethylene plate layer and an outer steel plate layer which are arranged in the containment structure. According to the radiation shielding system provided by the invention, the total radiation shielding weight can be reduced by 20-40% while the radiation shielding effect is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of floating nuclear power technology, in particular to a floating nuclear power platform and a radiation shielding system thereof. Background Art

[0002] A floating nuclear power plant (FNP) is a mobile nuclear power plant built on a floating platform. With its high energy density, clean, low-carbon technology, long endurance, and flexible mobility, FNPs offer a key solution for sustained power and energy supply in deep-sea resource development and carbon reduction in the marine sector.

[0003] Floating nuclear power plants usually use dispersed reactors and primary circuit systems, which inevitably generate radioactivity during operation. To ensure the life, health and radiation safety of workers on nuclear-powered floating platforms, radiation shielding is required for the radioactive sources in the reactors and primary circuits of floating nuclear power plants.

[0004] For dispersed reactors and primary circuit systems, land-based nuclear power plants generally use the containment vessel and its internal concrete structures as shielding. The main equipment of the reactor and the primary circuit are first separated and shielded by closed concrete compartments, and finally surrounded by the concrete structure of the containment vessel, which is heavy and large in size.

[0005] Unlike land-based nuclear power plants, nuclear-powered floating platforms have limited space and weight resources and compact equipment layout, making it difficult to set up closed compartment separation and shielding for the reactor and primary-loop system piping equipment. This puts higher demands on efficient radiation shielding and multifunctional integrated design. Summary of the Invention

[0006] The main purpose of the present invention is to provide a floating nuclear-powered platform and a radiation shielding system thereof, aiming to reduce the weight and size of the shielding system while ensuring the shielding effect.

[0007] To achieve the above-mentioned object, the present invention provides a radiation shielding system for a floating nuclear power platform, comprising a primary shielding structure, a combined shielding structure and a containment shielding structure, wherein: The primary shielding structure cover is arranged outside the reactor pressure vessel to provide primary shielding therefor, the combined shielding structure is sleeved outside the primary circuit pipeline and its ancillary equipment, and the containment shielding structure is arranged inside the containment structure; The primary shielding structure includes a first insulation layer wrapped around the outside of the pressure vessel shell, a shielding water tank covered outside the first insulation layer, and a shielding material layer covered outside the shielding water tank, wherein the shielding water tank is hollow inside to accommodate water; The combined shielding structure includes a high-density alloy layer sheathed on the outside of the primary circuit pipeline and its auxiliary equipment, and a second thermal insulation layer sheathed outside the high-density alloy layer; The containment shielding structure comprises a lead plate, a polyethylene plate layer, a boron-containing polyethylene plate layer and an outer steel plate layer which are arranged in the containment structure.

[0008] Preferably, the primary shielding structure further includes an alloy layer located between the inner side wall of the shielding water tank and the first thermal insulation layer.

[0009] Preferably, the side walls of the shielding water tank are made of stainless steel.

[0010] Preferably, the first thermal insulation layer and the second thermal insulation layer are both metal reflective thermal insulation layers; the thickness of the combined shielding structure is 150 mm to 300 mm, and the total thickness of the primary shielding structure is 1 m to 2 m.

[0011] Preferably, the shielding material layer is a tungsten boron polyethylene shielding layer.

[0012] Preferably, the high-density alloy layer and the second thermal insulation layer both form a sleeve-shaped structure, and the high-density alloy layer and the second thermal insulation layer both adopt a multi-section structure outside the single-loop pipeline, and the multi-section structures are connected by a tongue-and-groove structure, and each section of the high-density alloy layer and the second thermal insulation layer adopts a petal structure in the circumferential direction, and the petal structures are fixed with fasteners to fasten each section of the high-density alloy layer or the second thermal insulation layer to the outside of the single-loop pipeline.

[0013] Preferably, the containment shielding structure includes a lead plate, a polyethylene layer, a boron-containing polyethylene layer and an outer steel plate layer, which are arranged in sequence from the inside to the outside.

[0014] Preferably, the lead plate, polyethylene layer, boron-containing polyethylene layer and outer steel plate layer are arranged in sequence from inside to outside.

[0015] Preferably, the thickness of the containment shielding structure is 300 mm to 600 mm.

[0016] The present invention also provides a radiation shielding system for a floating nuclear power platform.

[0017] The radiation shielding system proposed by the present invention has the following beneficial effects: 1. Compared with traditional land-based nuclear power plant solutions, the Monte Carlo method is used for calculation and analysis, which can reduce the total weight of radiation shielding by 20% to 40% while ensuring the radiation shielding effect: 2. The use of highly efficient radiation shielding materials such as steel, lead, composite shielding materials, tungsten, and water is expected to reduce weight by approximately 10% to 20%; 3. The use of an integrated pre-partial shielding structure of "tungsten alloy-insulation layer" for the primary circuit system is expected to reduce the radiation shielding weight by 10% to 20%.

[0018] 4. This radiation shielding system has the advantages of simple structure and good shielding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of the radiation shielding system of the floating nuclear-powered platform of the present invention; Figure 2 It is a schematic cross-sectional view of the primary shielding structure in the radiation shielding system of the floating nuclear power platform of the present invention; Figure 3 It is a schematic cross-sectional view of the combined shielding structure in the radiation shielding system of the floating nuclear power platform of the present invention; Figure 4 for Figure 3 The cross-sectional structural diagram in the AA direction is shown; Figure 5 for Figure 4 The enlarged structural diagram of the details at C is shown; Figure 6 for Figure 3 Schematic diagram of the cross-sectional structure in the BB direction; Figure 7 for Figure 6 The detailed enlarged structural diagram of point D is shown; Figure 8 The schematic diagram of the structure of the containment shielding structure in the radiation shielding system of the floating nuclear power platform of the present invention is shown.

[0020] In the figure, 1-primary shielding structure, 11-first insulation layer, 12-alloy layer, 13-inner wall of shielding water tank, 14-inner chamber of shielding water tank, 15-outer wall of shielding water tank, 16-shielding material layer, 2-combined shielding structure, 21-high-density alloy layer, 22-second insulation layer, 3-containment shielding structure, 31-lead plate, 32-polyethylene layer, 33-boron-containing polyethylene layer, 34-outer steel plate layer, 4-containment structure, 5-reactor pressure vessel, 6-coolant pipeline, 7-main pump, 8-steam generator, 9-core.

[0021] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0022] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0023] It should be noted that in the description of the present invention, the terms "transverse," "longitudinal," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] The present invention provides a radiation shielding system for a floating nuclear-powered platform.

[0025] Reference Figures 1 to 3 In this preferred embodiment, a radiation shielding system for a floating nuclear power platform includes a primary shielding structure 1, a combined shielding structure 2, and a containment shielding structure 3, wherein: The primary shield structure 1 is mounted on the outside of the reactor pressure vessel 5 to provide primary shielding therefor. The combined shield structure 2 is mounted on the outside of the primary circuit pipeline (i.e., the coolant pipeline 6) and its ancillary equipment. The containment shield structure 3 is mounted inside the containment structure 4. The primary shielding structure 1 includes a first insulation layer 11 wrapped around the outside of the pressure vessel shell, a shielding water tank covered outside the first insulation layer 11, and a shielding material layer 16 covered outside the shielding water tank. The shielding water tank is hollow inside to accommodate water. The combined shielding structure 2 includes a high-density alloy layer 21 that is sheathed around the primary circuit piping and its ancillary equipment, and a second insulation layer 22 that is sheathed around the high-density alloy layer 21. The high-density alloy typically contains tungsten at least 90% by mass and has a density of 17 g / cm³ or higher.

[0026] Furthermore, the primary shielding structure 1 further includes an alloy layer 12 located between the inner wall of the shielding water tank and the first thermal insulation layer 11 , and the alloy layer 12 is made of a high-density alloy.

[0027] In this embodiment, the side walls of the shielding water tank are made of stainless steel.

[0028] In this embodiment, both the first insulation layer 11 and the second insulation layer 22 are metal reflective insulation layers. The metal reflective insulation structure is composed of multiple enclosed, bright, mirror-like block structures. Its outer shell is composed of stainless steel panels, end plates, and ring plates, providing a certain degree of structural strength. The interior is composed of stacked stainless steel reflective foil.

[0029] The primary shielding structure 1 is mainly used to reduce the radiation of the core and reduce the heat dissipation from the reactor to the containment space. In this embodiment, the shielding material layer 16 is a tungsten boron polyethylene shielding layer.

[0030] The high-density alloy layer 21 inside the shielding water tank helps reduce shielding volume and weight, rapidly reducing neutron and gamma radiation rates. The inner water layer of the shielding water tank provides excellent neutron moderation, while also providing a certain shielding effect against gamma radiation, absorbing and shielding heat release, and providing a water source for system replenishment and safety system water use. The outer shielding material layer 16 of the shielding water tank is a tungsten-boron polyethylene shielding layer, which further attenuates neutrons and gamma rays while also shielding secondary gamma radiation generated by neutrons, reducing it to a safe level. The total thickness of the primary shielding structure 1 is typically 1 to 2 meters, requiring comprehensive shielding optimization calculations based on the reactor source term, material combination distribution, resource cost, and economic efficiency.

[0031] Specifically, refer to Figure 1 The primary circuit pipeline and its ancillary equipment include the primary circuit main coolant pipeline, main pump 7 and steam generator 8 and other main primary circuit pipelines and equipment.

[0032] Combined with reference Figures 3 to 7 The high-density alloy layer 21 and the second insulation layer 22 both form a sleeve-shaped structure. The high-density alloy layer 21 and the second insulation layer 22 both adopt a multi-section structure outside the first-loop pipeline. The multi-section structures are connected by a tongue-and-groove structure to ensure the sealing of the connection.

[0033] Each segment of the high-density alloy layer 21 and the second insulation layer 22 adopts a circumferentially split-petal structure (a two-petal structure is used as an example in the figure). Fasteners are used to secure each segment of the high-density alloy layer 21 or second insulation layer 22 to the exterior of the primary circuit piping. The thickness of the combined shielding structure 2 ranges from 150 mm to 300 mm. The thickness of the high-density alloy layer 21 is optimized based on the intensity and distribution of the radioactive source term, while the thickness of the second insulation layer 22 is determined based on the temperature requirements of the main cooling pipe and the containment vessel.

[0034] In this embodiment, a combined shielding structure 2 is used, which can, on the one hand, shield the activation products such as N-16 in the reactor main coolant equipment and the gamma rays of the fission product decay, thereby reducing the pressure of the containment shield; on the other hand, it can reduce the heat dissipation from the primary circuit pipeline and equipment to the containment.

[0035] To effectively reduce the shield's volume and weight while ensuring effective shielding, and to facilitate installation and construction, a high-density alloy layer 21 is used on the inside. This layer has excellent mechanical strength and provides effective shielding against both thermal neutrons and gamma rays. It can be directly installed as a structural component on the outside of pipelines and equipment, secured with bolts. To minimize radiation leakage, a staggered installation method is used. The outside utilizes a metal reflective insulation structure that can be directly installed on the external structure. Considering heat dissipation from the mounting structure, a ferrule and bolt mounting method is used.

[0036] Specifically, in this embodiment, referring to Figure 8 The containment shielding structure 3 consists of, arranged from the inside out, lead plates 31, a polyethylene layer 32, a boron-containing polyethylene layer 33, and an outer steel plate layer 34 (the containment structure 4 is T-shaped). This combined structure optimizes shielding effectiveness while optimizing weight, reducing costs, and facilitating installation and construction. The lead plates 31 on the inside of the containment structure 4 attenuate transmitted reactor and primary circuit gamma rays and further reduce the energy of high-energy neutrons. Adjacent to the lead plates 31, a polyethylene layer 32 and a boron-containing polyethylene layer 33 rapidly moderate and absorb neutrons, reducing neutron radiation. The outer steel plate layer 34 is installed by welding.

[0037] Lead sheet 31, polyethylene layer 32, and boron-containing polyethylene layer 33 are all applied in a multi-layered structure on the exterior of containment structure 4. The thickness of containment shielding structure 3 ranges from 300 mm to 600 mm. Specifically, the thickness of the containment shielding material must be optimized based on the reactor and primary source, primary shielding structure 1, the combined shielding and insulation structure for primary piping and equipment, and radiation safety limit requirements.

[0038] The radiation shielding system proposed by the present invention has the following beneficial effects: 1. Compared with traditional land-based nuclear power plant solutions, the Monte Carlo method is used for calculation and analysis, which can reduce the total weight of radiation shielding by 20% to 40% while ensuring the radiation shielding effect: 2. The use of highly efficient radiation shielding materials such as steel, lead, composite shielding materials, tungsten, and water is expected to reduce weight by approximately 5% to 10%; 3. The use of an integrated pre-partial shielding structure of "tungsten alloy-insulation layer" for the primary circuit system is expected to reduce the radiation shielding weight by 15% to 25%.

[0039] 4. This radiation shielding system has the advantages of simple structure and good shielding effect.

[0040] In this preferred embodiment, a radiation shielding system for a floating nuclear-powered platform is provided. The specific structure and beneficial effects of the radiation shielding system refer to the above embodiments and will not be described in detail here.

[0041] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's description and drawings, or directly or indirectly applied to other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A radiation shielding system for a floating nuclear-powered platform, characterized in that: It includes a primary shielding structure, a combined shielding structure and a containment shielding structure, among which: The primary shielding structure cover is arranged outside the reactor pressure vessel to provide primary shielding therefor, the combined shielding structure is sleeved outside the primary circuit pipeline and its ancillary equipment, and the containment shielding structure is arranged inside the containment structure; The primary shielding structure includes a first insulation layer wrapped around the outside of the pressure vessel shell, a shielding water tank covered outside the first insulation layer, and a shielding material layer covered outside the shielding water tank, wherein the shielding water tank is hollow inside to accommodate water; The combined shielding structure includes a high-density alloy layer sheathed on the outside of the primary circuit pipeline and its auxiliary equipment, and a second thermal insulation layer sheathed outside the high-density alloy layer; The containment shielding structure comprises a lead plate, a polyethylene plate layer, a boron-containing polyethylene plate layer and an outer steel plate layer which are arranged in the containment structure.

2. The radiation shielding system for a floating nuclear-powered platform according to claim 1, wherein: The primary shielding structure also includes an alloy layer located between the inner side wall of the shielding water tank and the first thermal insulation layer.

3. The radiation shielding system for a floating nuclear-powered platform according to claim 1, wherein: The side walls of the shielding water tank are made of stainless steel.

4. The radiation shielding system for a floating nuclear-powered platform according to claim 1, wherein: The first insulation layer and the second insulation layer are both metal reflective insulation layers; the thickness of the combined shielding structure is 150mm to 300mm, and the total thickness of the primary shielding structure is 1m to 2m.

5. The radiation shielding system for a floating nuclear-powered platform according to claim 1, wherein: The shielding material layer is a tungsten boron polyethylene shielding layer.

6. The radiation shielding system for a floating nuclear-powered platform according to claim 1, wherein: The high-density alloy layer and the second thermal insulation layer both form a sleeve-shaped structure. The high-density alloy layer and the second thermal insulation layer both adopt a multi-section structure outside the first-loop pipeline. The multi-section structures are connected by a tongue-and-groove structure. Each section of the high-density alloy layer and the second thermal insulation layer adopts a petal structure in the circumferential direction. The petal structures are fixed with fasteners to fasten each section of the high-density alloy layer or the second thermal insulation layer to the outside of the first-loop pipeline.

7. The radiation shielding system for a floating nuclear power platform according to any one of claims 1 to 6, characterized in that: The lead plate, polyethylene layer, boron-containing polyethylene layer and outer steel plate layer are arranged in sequence from the inside to the outside.

8. The radiation shielding system for a floating nuclear-powered platform according to claim 7, wherein: The lead plate, polyethylene layer and boron-containing polyethylene layer are all laid inside the containment structure in a layered multi-block structure.

9. The radiation shielding system for a floating nuclear-powered platform according to claim 7, wherein: The thickness of the containment shielding structure is 300 mm to 600 mm.

10. A floating nuclear-powered platform, characterized in that: The invention comprises a reactor pressure vessel and its piping, and also comprises a pressure vessel shell radiation shielding system according to any one of claims 1 to 9.

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