Containment

Abstract

The invention discloses a multi-layer steel lining containment structure, and the containment comprises an inner layer steel lining which is in contact with gas in the containment and is used for encapsulating radioactive substances; the outer-layer steel lining and the inner-layer steel lining form an interlayer, and the interlayer is provided with a filling space; the concrete shell is arranged on the outer layer of the outer-layer steel lining so as to protect the outer layer of the outer-layer steel lining; the filling space is filled with the phase change material, and the phase change performance of the phase change material can realize defect self-repairing of the containment. According to the structure, multiple functions of passive impact buffering, pressure balancing, rapid heat guiding-out, defect repairing and the like can be integrated.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear engineering, and in particular to a novel multi-layer steel-lined containment structure of a nuclear power plant. Background Art

[0002] At present, the containment structures used in nuclear power plants at home and abroad are mainly divided into four categories: the reactor type represented by the Chernobyl nuclear power plant has no containment, only a non-pressurized concrete reactor building; the reactor type represented by the Fukushima nuclear power plant has only a single-layer steel shell, and the outer layer is a non-pressurized concrete reactor building; a single-layer steel-lined concrete containment; and some reactor types have double-layer containment, and both the inner and outer containment are single-layer steel-lined concrete containment. The containment of the above structures can only achieve a single function.

[0003] Patent CN114352086A discloses an impact-resistant containment shell, the structure of which is an inner concrete containment shell 1 and an outer concrete anti-collision containment shell 2, which are connected by a skeleton 3 to form a whole, and aggregate is filled between the two layers of concrete containment shells to absorb impact energy. The patent described in the document can only buffer the impact force of external impact. The design is an external extension design based on the traditional containment shell, and the problem it addresses is external impact. It is also unable to achieve multiple functions such as passive impact buffering, pressure balance, rapid heat extraction, and defect repair.

[0004] In view of the above technical problems, the present invention is specially introduced. Summary of the invention

[0005] The main purpose of the present invention is to provide a multi-layer steel-lined containment structure, which can realize passive impact buffering, pressure balance, rapid heat extraction and defect repair in one. In order to achieve the above purpose, the present invention provides a containment, which includes: an inner steel lining, which contacts the gas in the shell and is used to encapsulate radioactive materials; an outer steel lining, which forms a sandwich with the inner steel lining, and the sandwich has a filling space; a concrete shell, which is arranged on the outer layer of the outer steel lining to protect the outer layer of the outer steel lining; and a phase change material is filled in the filling space, and the phase change performance of the phase change material can realize the self-repair of the defects of the containment.

[0006] The following is a further optimization of the above scheme by the present invention:

[0007] Furthermore, the phase change material undergoes a phase change between 50°C and 100°C.

[0008] Furthermore, the melting point of the phase change material is 50°C to 70°C.

[0009] Furthermore, the phase change material undergoes phase changes between solid-liquid, solid-gas, and solid-liquid-gas at 50°C to 100°C.

[0010] Furthermore, the phase change material is a composite phase change material.

[0011] Furthermore, the phase change material includes paraffin wax.

[0012] Furthermore, the diameter of the paraffin particles is 6 mm to 10 mm.

[0013] Furthermore, the outer steel lining has a thickness of t1, the inner steel lining has a thickness of t2, and the distance between the inner side of the outer steel lining and the outer side of the inner steel lining is t3, where t3=0.9-1.1.

[0014] Furthermore, the interlayer is a segmented structure, and layered partitions are arranged at the connection points of the segmented structures.

[0015] Furthermore, the containment vessel also includes an upper pipeline and / or a lower pipeline to compensate or discharge the phase change material.

[0016] By applying the technical solution of the present invention, at least the following beneficial effects are achieved:

[0017] 1. The new containment structure has the function of pressure balance through multi-layer steel lining and phase change materials between them, which can inhibit radioactive leakage.

[0018] 2. The new containment structure uses multi-layer steel linings and phase change materials between them to make the containment have the function of pressure shock buffering, reducing the damage to the concrete shell 3 caused by the pressure increase in accident conditions.

[0019] 3. The new containment structure has the function of self-repairing defects through multi-layer steel linings and phase change materials between them. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 A schematic diagram of a multi-layer steel-lined containment structure is shown;

[0022] Figure 2 A schematic diagram of the cross-sectional structure of a multi-layer steel-lined containment is shown;

[0023] Figure 3 A schematic diagram of the multi-layer steel lined containment structure is shown.

[0024] The above drawings include the following reference numerals:

[0025] 1. Inner steel lining; 2. Outer steel lining; 3. Concrete shell; 4. Filling space;

[0026] 5. Lower pipe; 6. Upper pipe. DETAILED DESCRIPTION

[0027] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] The present invention is further described in detail below in conjunction with specific embodiments, and these embodiments cannot be understood as limiting the scope of protection claimed by the present invention. The term "including" when used indicates the existence of a feature, but does not exclude the existence or addition of one or more other features; the orientation or position relationship indicated by the terms "lateral", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention; in addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance.

[0029] In the description, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0030] In order to realize the multi-functions of passive impact buffering, pressure balance, rapid heat extraction and defect repair in one, the present invention proposes a multi-layer steel lined concrete containment, which can realize multiple functions at the same time by filling the annular space between the multiple layers of steel linings with specific substances.

[0031] Figure 1-Figure 3 The containment shown is a two-layer steel lining. According to actual needs, the containment can also be a three-layer or more steel lining structure.

[0032] like Figure 1As shown, the containment shell includes an inner steel lining 1, an outer steel lining 2 and a concrete shell 3. The inner steel lining 1 is in contact with the gas in the shell and is used to encapsulate radioactive substances. The outer steel lining 2 forms a sandwich with the inner steel lining 1. The sandwich has a filling space 4, and the filling space 4 is filled with a phase change material. The phase change performance of the phase change material can realize the self-repair of defects in the containment shell. The concrete shell 3 is arranged on the outer layer of the outer steel lining 2 to protect the outer layer of the outer steel lining 2. The material of the inner steel lining 1 and the outer steel lining 2 is steel, which can be low-alloy high-strength steel. Through the interlayer and the phase change material inside it, the heat can be quickly discharged. When an accident occurs, the inner steel lining 1 can be quickly cooled and depressurized to achieve the reduction of the containment shell.

[0033] In the attached drawings and the following implementation examples, a typical structure of a double-layer steel lining is provided only to complete the description of the innovative points of the new structure. As long as the actual number of steel lining layers is two or more, the specific number of layers, whether there are pipelines, and the number of pipelines do not affect the functional realization and are all within the scope of the present invention.

[0034] The outermost layer of the containment is a concrete shell 3, and the outer steel lining 2 with a thickness of t1 is in direct contact with the inner layer of concrete. The innermost layer is an inner steel lining 1 with a thickness of t2. The distance between the inner side of the outer steel lining 2 and the outer side of the inner steel lining 1 is t3, t3 = 0.9 ~ 1.1 (t1 + t2). The construction process of the containment adopts segmented modular construction, in which the interlayer is a layered structure, which is welded by multiple layers of prefabricated sealing chamber sections. The inner steel lining 1 is a nuclear-grade shell, and the outer steel lining is a non-nuclear-grade shell. The interlayer serves as the inner template for concrete pouring.

[0035] The sandwich is provided with layered partitions at the joints of the segmented structures. The layered partitions arranged at different heights play the role of connecting and strengthening the skeleton.

[0036] The new containment structure has a pressure balance function through multiple layers of steel linings and phase change materials between them, which can inhibit radioactive leakage. When an accident occurs, along with the temperature rise, the pressure between the steel linings increases through phase change of phase change materials and other measures. The pressure is higher than the atmospheric pressure but lower than the pressure inside the shell, which reduces the differential pressure between the radioactive gas inside the shell and the outside, and can reduce the leakage rate of the containment.

[0037] The filling space 4 between the steel liners can be filled with different materials according to different design requirements. The containment also includes an upper pipe 6 and / or a lower pipe 5 to compensate or discharge the phase change material.

[0038] In the filling space 4, material particles and other mixed aggregates with "solid-gas" and "solid-liquid" phase change characteristics accompanying temperature changes are filled. At the beginning of the accident, the pressure in the shell rose rapidly, the inner steel lining 1 expanded outward, and the material particles in the filling space 4 played a role of physical support and buffering, and the effect of transferring to the outer steel lining 2 was weakened. The temperature in the shell rises, and under the heat conduction of the inner steel lining 1, the temperature of the filling space 4 rises, and the filling material absorbs the heat in the shell. When the temperature of the filling space 4 reaches the critical temperature of the phase change material, the phase change material in the filling space 4 changes from solid to liquid / gas, quickly absorbs heat, and suppresses the further increase of temperature and pressure in the shell. As the phase change material is transformed into a gaseous substance, the pressure in the filling space 4 rises, reducing the pressure difference with the shell and suppressing the outflow of radioactive substances. Among them, the pressure increase amplitude is related to the ratio of solid-gas phase change material.

[0039] The new containment structure uses multiple layers of steel linings and phase change materials between them to make the containment have the function of pressure shock buffering, reducing the damage to the concrete shell 3 caused by the pressure rise in accident conditions. Since the phase change material is not dense and filled, the gaps between the phase change materials and the free space between the multiple layers of steel linings will allow the inner containment to expand and deform rapidly, reducing the cracking damage caused by its deformation to the external concrete.

[0040] The new containment structure has the function of self-repairing defects through the multi-layer steel lining and the phase change materials therebetween. The gaseous substance transformed by the phase change material flows from the filling space 4 into the concrete shell 3 through defects such as cracks. When it reaches the low temperature side, it returns from the gaseous state to the solid state, automatically completing the crack sealing, so that the steel lining has the function of self-repairing defects. When an accident occurs, the temperature of the multi-layer steel lining space rises, the phase change material undergoes a phase change, and the gaseous phase change material will diffuse to the outside of the concrete through defects such as cracks. On the concrete side, the gaseous phase change material is cooled and re-solidified to seal the existing cracks.

[0041] Phase change materials are mainly phase change materials, which can be a single phase change material, a variety of composite phase change materials, or a combination of phase change materials and non-phase change aggregates. Phase change materials undergo phase changes in three forms: solid-liquid, solid-gas, and solid-liquid-gas between 50°C and 100°C. Phase change materials that meet the above characteristics, combined with the design of multi-layer steel lining, can meet the safety performance of the containment. For the selected phase change materials and phase change forms, when determining the loading rate or mixing ratio, it is also necessary to consider the impact of phase change on the interlayer filling space 4. When selecting materials for solid-gas phase change, additional consideration should be given to the potential impact of gas escape on the external environment.

[0042] Preferably, the melting point of the phase change material is 50°C to 70°C, and the phase change material undergoes three phase changes between solid-liquid, solid-gas, and solid-liquid-gas at 50°C to 100°C.

[0043] In this embodiment, paraffin particles are used as an example to illustrate the effect of phase change materials and multi-layer steel lined containment. Preferably, the diameter of the paraffin particles is 6 mm to 10 mm. Paraffin is filled in the filling space 4, and the melting point of the paraffin particles is controlled at about 60° C. by controlling the carbon content of the paraffin.

[0044] During the normal operation of the nuclear power plant, the temperature inside the containment is controlled at about 25°C, and the paraffin particles between the double-layer steel linings always exist in the state of solid particles and will not melt. When an accident occurs in a nuclear power plant, the temperature and pressure inside the containment will rise. The paraffin between the interlayers stores heat to suppress the temperature rate inside the shell. The inner steel lining 1 is heated and transfers heat to the paraffin particles in direct contact. The paraffin particles expand due to heat, and the temperature in the interlayer rises at the same time, so the pressure in the interlayer will rise. This inhibits the gas inside the inner steel lining 1 from leaking between the interlayers to a certain extent. During the heating of the interlayer, the pressure rise value in the interlayer can be controlled by the filling rate of the paraffin and the proportion of the solid-gas phase change material.

[0045] When the temperature of the paraffin wax in the inner steel lining 1 reaches the melting point, it begins to melt and absorb more latent heat. It begins to flow along the wall, further accelerating the melting of the paraffin wax between the interlayers, quickly taking away the heat of the inner steel lining 1, and effectively suppressing the temperature rise inside the containment. Since the interlayer is filled with paraffin particles, there are gaps between the particles, and some paraffin particles have melted after being heated. Therefore, during the accident, the interlayer has a good buffering effect. During the period of pressure rise inside the containment, the force first acts on the inner steel lining 1, and the deformation and impact force caused by the inner steel lining 1 will be completely absorbed and buffered by the interlayer, and will not be transmitted to the outer steel lining 2. Therefore, the outer steel lining 2 and the external concrete shell 3 will not be subjected to the impact force and deformation caused by the rapid rise in pressure inside the shell. This effect effectively guarantees the integrity of the concrete shell 3.

[0046] At the same time, as more paraffin particles melt, the paraffin liquid will gradually cover most of the outer steel lining 2, and the part not covered by the liquid will also be filled with a small amount of paraffin vapor. Therefore, if there is a leak in the outer steel lining 2, the paraffin liquid or vapor will pass through the outer steel lining 2 and enter the concrete voids of the concrete shell 3. Since the outermost layer of the concrete shell 3 is in contact with the atmosphere, the temperature outside the concrete shell 3 is much lower than the melting point of paraffin, so the paraffin will solidify into a solid in the concrete shell 3, and the voids in the concrete itself will be sealed with wax, which realizes the automatic repair of concrete defects and completely avoids the diffusion of gas in the outer steel lining 2 into the environment.

[0047] After the accident, the temperature and pressure inside the containment vessel drop. The paraffin between the interlayers releases heat, suppressing the rate of temperature drop inside the vessel and preventing damage to the containment vessel caused by rapid pressure drop inside the vessel. During this process, the paraffin liquid or vapor between the interlayers gradually solidifies. The paraffin that solidifies again can function again. In the event of an accident, it can still perform its safety function according to the above process when heated.

[0048] In summary, from the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0049] 1. The new containment structure has the function of pressure balance through multi-layer steel lining and phase change materials between them, which can inhibit radioactive leakage.

[0050] 2. The new containment structure uses multi-layer steel linings and phase change materials between them to make the containment have the function of pressure shock buffering, reducing the damage to the concrete shell 3 caused by the pressure increase in accident conditions.

[0051] 3. The new containment structure has the function of self-repairing defects through multi-layer steel linings and phase change materials between them.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A containment vessel, characterized in that: The containment shell comprises: An inner steel lining (1), in contact with the gas in the shell, for enclosing radioactive materials; An outer steel lining (2) forms a sandwich with the inner steel lining (1), wherein the sandwich has a filling space (4); A concrete shell (3), wherein the concrete shell (3) is arranged on the outer layer of the outer steel lining (2) to protect the outer layer of the outer steel lining (2); The filling space (4) is filled with a phase change material, and the phase change performance of the phase change material can realize self-repair of defects of the containment vessel.

2. The containment vessel according to claim 1, characterized in that: The phase change material undergoes phase change between 50°C and 100°C.

3. The containment vessel according to claim 2, characterized in that: The melting point of the phase change material is 50°C to 70°C.

4. The containment vessel according to claim 3, characterized in that: The phase change material undergoes phase changes in three forms: solid-liquid, solid-gas, and solid-liquid-gas at 50°C to 100°C.

5. The containment vessel according to claim 4, characterized in that: The phase change material is a composite phase change material.

6. The containment vessel according to claim 5, characterized in that: The phase change material includes paraffin wax.

7. The containment vessel according to claim 6, characterized in that: The diameter of the paraffin particles is 6 mm to 10 mm.

8. The containment vessel according to claim 7, characterized in that: The outer steel lining (2) has a thickness of t1, the inner steel lining (1) has a thickness of t2, the distance between the inner side of the outer steel lining (2) and the outer side of the inner steel lining (1) is t3, and t3=0.9~1.1(t1+t2).

9. The containment vessel according to claim 8, characterized in that: The interlayer is a segmented structure, and layered partitions are arranged at the connection points of the segmented structures.

10. The containment vessel according to claim 9, characterized in that: The containment vessel further comprises an upper pipeline and / or a lower pipeline to compensate or discharge the phase change material.

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