Snow fence height calculation method, system, and ventilation system and protection system

Abstract

The present application relates to the snow accumulation height calculation method, system and ventilation system and protection system, wherein the snow accumulation height calculation method comprises the following steps: obtaining the snow surface length in the horizontal direction away from the wall; obtaining the windward side snow accumulation height according to the snow surface length and the snow load of the snow surface; obtaining the uniform snow load thickness on the snow surface, and obtaining the total snow accumulation height according to the uniform snow load thickness and the windward side snow accumulation height; and outputting the minimum height of the target object arranged on the wall according to the total snow accumulation height; the method can obtain the minimum height of the target object arranged on the wall, so as to avoid the adverse effects of snow accumulation on the target object, such as shielding and blocking.

Description

Technical Field

[0001] This invention relates to the field of nuclear-grade mechanical equipment in nuclear power plants, and more particularly to methods, systems, ventilation systems, and protection systems for calculating snow accumulation height. Background Technology

[0002] To ensure the nuclear safety functions of a nuclear power plant, protection against internal and external hazards must be comprehensively considered before the plant's construction and design. Among these, the ventilation system, as a crucial support system for nuclear safety functions, directly participates in the radiation containment function, one of the three major safety functions of a nuclear power plant, and also provides ventilation and cooling for front-end systems and safety-grade instrumentation systems. The air intake and exhaust vents of the ventilation system are generally located at the plant boundary, requiring special attention to protection against external hazards.

[0003] However, current technologies do not take snow accumulation into account when determining the height of ventilation openings, often resulting in them being blocked by snow in extreme weather conditions. Therefore, determining the appropriate ventilation opening height to avoid being affected by snow accumulation is a question worth exploring.

[0004] Secondly, external disasters also include projectiles, tornadoes, and blast shockwaves; how to prevent these disasters from damaging the ventilation system and its vents is also a problem that needs to be solved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method, system, ventilation system and protection system for calculating the height of snow accumulation.

[0006] The technical solution adopted by this invention to solve its technical problem is: to construct a method for calculating the height of snow accumulation, wherein the snow accumulation refers to the snow piled up around a wall standing on a snow-covered surface, and the height calculation method includes the following steps:

[0007] S1: Obtain the length of the snow surface in the horizontal direction away from the wall;

[0008] S2: Based on the length of the snow surface and the snow load on the snow surface, the snow accumulation height on the windward side is obtained;

[0009] S3: Obtain the uniformly distributed snow load thickness on the snow surface, and obtain the total snow accumulation height based on the uniformly distributed snow load thickness and the snow accumulation height on the windward side;

[0010] S4: Based on the total height of the snow pile, output the minimum height that the target object on the wall should be set at.

[0011] In some embodiments, in step S2, the snow accumulation height on the windward side is calculated according to formula a; formula a is:

[0012]

[0013] Among them, h d W refers to the height of snow accumulation on the windward side. b P refers to the length of the snow-covered surface. g Refers to the snow load on the snow surface.

[0014] In some embodiments, obtaining the uniformly distributed snow load thickness on the snow surface includes: calculating the uniformly distributed snow load thickness according to formula b;

[0015] The relation b is:

[0016]

[0017] Among them, h b P refers to the thickness of the uniformly distributed snow load. g The term refers to the snow load on the snow surface, ρ refers to the snow density, and g refers to the acceleration due to gravity.

[0018] In some embodiments, obtaining the uniformly distributed snow load thickness on the snow surface includes:

[0019] The uniformly distributed snow load thickness is obtained based on the snow accumulation height on the windward side.

[0020] The present invention also constructs a snow accumulation prevention height calculation system, comprising:

[0021] The first acquisition module is used to acquire the length of the snow surface in the horizontal direction away from the wall;

[0022] The first calculation module is used to obtain the snow accumulation height on the windward side based on the length of the snow surface and the snow load on the snow surface;

[0023] The second calculation module is used to obtain the uniformly distributed snow load thickness on the snow surface, and to obtain the total snow accumulation height based on the uniformly distributed snow load thickness and the snow accumulation height on the windward side.

[0024] The output module is used to output the minimum height that the target object on the wall should be set at, based on the total height of the snow pile.

[0025] The present invention also constructs a ventilation system arranged inside a nuclear power plant building, wherein the ventilation opening of the ventilation system is installed on the first side wall of the nuclear power plant building; the first side wall is provided with a top surface connected to its outer wall surface and located below the ventilation opening; the top surface includes the ground or the roof of the building;

[0026] The height of the vent from the top surface is at least greater than the distance H1, which can be obtained according to the above-mentioned method for calculating the height of snow-proofing.

[0027] The present invention also constructs a nuclear power plant protection system for protecting safety-grade items arranged in a nuclear power plant building. The safety-grade items include a ventilation system. The nuclear power plant building includes a vertical first side wall. The ventilation opening of the ventilation system is located on the first side wall. The first side wall also has a top surface connected to its outer wall surface and located below the ventilation opening.

[0028] The nuclear power plant protection system includes a baffle for shielding the ventilation opening from foreign objects; the baffle is located outside the first side wall, and the minimum height of the baffle from the top surface is at least greater than the distance H2, which is obtained according to the above-mentioned method for calculating the height of snow accumulation prevention.

[0029] In some embodiments, the baffle has a fixed end and a free end, the fixed end being fixed to the first side wall; the free end facing the top surface and located below the vent, with a gap between it and the top surface and the first side wall respectively.

[0030] In some embodiments, the baffle includes a first parallel plate fixed at one end to the first side wall and a first vertical plate connected to the other end of the first parallel plate;

[0031] The first parallel plate is positioned above the ventilation opening on the first side wall, and the surface of the first vertical plate is opposite to the ventilation opening.

[0032] In some embodiments, the baffle is L-shaped, one end of the first parallel plate is vertically fixed to the first side wall, and the other end of the first parallel plate is vertically connected to the first vertical plate.

[0033] In some embodiments, the line connecting the lower end of the first vertical plate to the lowest point of the vent forms an angle α with the plane in which the first vertical plate is located; the angle α is between 20° and 40°.

[0034] In some embodiments, a passive shock wave valve is also included for connecting the ventilation system, wherein the passive shock wave valve isolates the ventilation duct when the ventilation duct of the ventilation system generates a negative pressure or overpressure exceeding a preset value.

[0035] In some embodiments, a dynamic isolation valve is also included for connecting the ventilation system, the dynamic isolation valve isolating the ventilation ducts of the ventilation system in the event of a ventilation system failure.

[0036] Implementing this invention has the following beneficial effects: This method for calculating the height of snow accumulation can determine the minimum height that the target object on the wall should be set at by calculating the total height of the snow accumulation, thereby avoiding the adverse effects of snow accumulation on the target object, such as obstruction and blockage. Attached Figure Description

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0038] Figure 1 This is a flowchart of the method for calculating the height of snow accumulation prevention according to the present invention;

[0039] Figure 2 This is a simulated structural diagram of the snow accumulation prevention height calculation method of the present invention applied to a nuclear power plant building;

[0040] Figure 3 This is a schematic diagram of the structure of the nuclear power plant protection system of the present invention in conjunction with the nuclear power plant building and ventilation system in some embodiments.

[0041] Reference numerals: 11. High-roofed building; 12. Low-roofed building; 111. Wall; 121. Snow surface; 122. Evenly distributed snow; 123. Snow accumulation section; 23. Nuclear power plant building; 231. First side wall; 2311. Ventilation opening; 232. Baffle; 2321. First parallel plate; 2322. First vertical plate; 2323. Opening; 3. Active isolation valve; 4. Passive shock wave resistant valve; 5. Ventilation system. Detailed Implementation

[0042] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or element referred to must have a specific orientation; therefore, they should not be construed as limitations on this invention.

[0043] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. The terms "first," "second," "third," etc., are only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0044] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0045] See Figure 1 This invention provides a method for calculating the height of snow accumulation to prevent snow buildup. This method can be applied to nuclear power plant buildings. By calculating the total height of snow accumulation, the minimum height that should be set for targets such as baffles, windows, and ventilation openings located on the plant boundary (walls) can be determined, thereby avoiding the adverse effects of snow accumulation on these targets, such as obstruction or blockage. Of course, this method for calculating the height of snow accumulation can also be applied to other scenarios that require calculating snow accumulation height, such as in the construction field, without specific limitations here.

[0046] like Figure 1 As shown, in some embodiments, the method for calculating the height of snow accumulation prevention includes the following steps:

[0047] S1: Obtain the length of the snow surface 121 in the horizontal direction away from the wall 111;

[0048] Understandably, snow piles typically form along walls, meaning snow accumulates around the perimeter of a wall standing on a snow-covered surface. Because wall 111 provides some support, snow tends to accumulate along it, forming snow piles. If baffles, windows, and vents on wall 111 are installed at a low height, they are easily covered or blocked by snow piles, thus losing their original function.

[0049] In some embodiments, see Figure 2 The roof of the nuclear power plant building 23 is stepped, forming a high-roof building 11 and a low-roof building 12 lower than the high-roof building 11. Ventilation openings are provided on the wall 111 of the high-roof building 11 facing the low-roof building 12. Figure 2 (Not shown in the image); the top surface of the low-roofed building 12 is a horizontal plane, perpendicular to the walls 111 of the high-roofed building 11. In snowy conditions, the top surface of the low-roofed building 12 serves as the snow accumulation surface 121, where snow accumulates and rises along the walls 111. In this embodiment, the length of the snow accumulation surface is... Figure 2 The length in the Wb direction marked in the figure can be obtained by measuring with tools such as a ruler.

[0050] In other embodiments, the nuclear power plant includes a nuclear power plant building 23 and another nuclear power plant building adjacent to the nuclear power plant building 23, the height of which is greater than the height of the other nuclear power plant building. The snow surface 121 can be the top surface (roof) of the other nuclear power plant building, which is a horizontal plane perpendicular to the wall 111. Snowflakes fall onto the roof of the other nuclear power plant building during snowfall, forming the snow surface 121; while the wall 111 can be a building wall in the nuclear power plant building 23 that is higher than and connected to the roof of the other nuclear power plant building.

[0051] In some embodiments, the snow surface 121 can be the ground surface, formed by snowflakes falling onto the ground during snowfall; while the wall 111 refers to the building wall standing on the ground, such as the building wall of the nuclear power plant building 23. Generally, the ground surface is a horizontal plane, perpendicular to the wall 111. It should be noted that, considering the length of the ground surface and the roof of the nuclear island building, the length of the snow pile on the snow surface is generally much shorter than the length of the snow surface itself. In this calculation method, the limitation on the length and height of the snow pile due to insufficient snow surface length caused by terrain is not considered. Therefore, optionally, the length of the snow surface can be taken as 50m, referencing the roof length of the nuclear island building.

[0052] S2: Based on the length of the snow cover and the snow load on the snow cover, the snow accumulation height on the windward side is obtained;

[0053] Understandably, considering environmental factors, the shape of the snow pile formed between the wall and the snow surface is generally roughly triangular, such as... Figure 2 The snowdrift section 123 is shown above the uniformly distributed snow 122 on the snow surface 121. Based on this, the snow accumulation height on the windward side is calculated through simulation.

[0054] The specific formula 'a' for calculating the snow accumulation height on the windward side is:

[0055]

[0056] Where hd represents the snow accumulation height on the windward side, Wb represents the length of the snow cover, and Pg represents the snow load on the snow cover. This snow load can be obtained from the snow pressure load data given in Table E.5 of Appendix E of the national standard "Load Code for Building Structures" GB50009. Optionally, the length of the snow cover can be taken as 50m, representing snow accumulation formed on a snow cover surface with a length of 50m.

[0057] S3: Obtain the uniformly distributed snow load thickness on the snow surface 121, and obtain the total snow accumulation height based on the uniformly distributed snow load thickness and the snow accumulation height on the windward side;

[0058] Understandably, the uniformly distributed snow load thickness refers to the thickness of the uniformly distributed snow accumulation 122 below the snowpack 123. In some embodiments, the uniformly distributed snow load thickness is calculated using the following formula b. Formula b is specifically:

[0059]

[0060] Where hb refers to the uniformly distributed snow load thickness, Pg refers to the snow load on the snow surface, ρ refers to the snow density, and g refers to the acceleration due to gravity. The snow density is expressed in t / m³. 3 The density can be obtained by combining the method in Appendix E of the national standard "Load Code for Design of Building Structures" GB50009 with local meteorological station records, or by using a density measuring instrument. g is the acceleration due to gravity (which can be taken as 9.8 m / s²). 2 ).

[0061] In some embodiments, due to strong outdoor winds and the blowing effect of the wind, the actual uniform snow load thickness is very small and cannot be accurately assessed. The uniform snow load thickness can be enveloped by taking an appropriate margin after obtaining the snow accumulation height on the windward side.

[0062] Understandably, the total height of the snow pile is the highest height that can be achieved by piling snow on the snow surface 121, and this total height of the snow pile is equal to the sum of the uniformly distributed snow load thickness and the snow pile height on the windward side.

[0063] S4: Based on the total height of the snow pile, output the minimum height that the target object on the wall should be set at.

[0064] Understandably, targets include baffles, windows, and vents located on or near wall 111 that need to be positioned above the snow pile. The distance between these targets and the top surface or ground of the low-roofed building 12 must be at least greater than the total height of the snow pile to prevent the snow pile from obscuring or blocking the targets.

[0065] The present invention also provides a snow accumulation prevention height calculation system. In some embodiments, the calculation system includes:

[0066] The first acquisition module is used to acquire the length of the snow surface 121 in the horizontal direction away from the wall 111;

[0067] The first calculation module is used to obtain the snow accumulation height on the windward side based on the length of the snow surface and the snow load on the snow surface;

[0068] The second calculation module is used to obtain the uniformly distributed snow load thickness on the snow surface 121, and to obtain the total snow accumulation height based on the uniformly distributed snow load thickness and the snow accumulation height on the windward side.

[0069] The output module is used to output the minimum height that the target object placed on the wall should be set according to the total height of the snow pile.

[0070] In some embodiments, the first calculation module calculates the snow accumulation height on the windward side according to relation a, which is:

[0071]

[0072] Where hd refers to the snow accumulation height on the windward side, Wb refers to the length of the snow surface, and Pg refers to the snow load on the snow surface.

[0073] In some embodiments, the second calculation module calculates the snow accumulation height on the windward side according to relation b, which is:

[0074]

[0075] Where hb refers to the uniformly distributed snow load thickness, Pg refers to the snow load on the snow surface, ρ refers to the snow density, and g refers to the gravitational acceleration.

[0076] In some embodiments, the second computing module includes:

[0077] The first calculation unit is used to obtain the uniformly distributed snow load thickness based on the snow accumulation height on the windward side;

[0078] The second calculation unit is used to obtain the total snow accumulation height based on the uniformly distributed snow load thickness and the snow accumulation height on the windward side.

[0079] See Figure 3The present invention also constructs a ventilation system arranged within a nuclear power plant building 23. The nuclear power plant building 23 may include a top wall and multiple side walls extending downwards along the edge of the top wall; the multiple side walls are vertical and perpendicular to the ground. The ventilation openings of the ventilation system are installed on a first side wall 231 among the multiple side walls; a top surface is provided outside the first side wall 231, connected to its outer wall surface and located below the ventilation opening 2311. This top surface may include the roof surface of the building or the ground.

[0080] Ventilation vent 2311 connects to the external environment of nuclear power plant building 23, and the elevation of ventilation vent 2311 should be higher than the outdoor snow accumulation height to prevent snow from accumulating on the vent side and causing freezing blockage. According to GB50019-2015, the minimum height for preventing snow accumulation on outdoor roofs should not be less than 1 meter from the ground, meaning the minimum height of ventilation vent 2311 should be greater than 1 meter.

[0081] Preferably, in order to more reliably determine the height between the vent 2311 and the top surface, the minimum height between the vent 2311 and the top surface can be obtained by relying on the above-mentioned snow-proofing height calculation method.

[0082] Understandably, in some embodiments, the nuclear power plant building 23 is built on the roof (ground), and the outer wall of the first side wall 231 is connected to the ground. In snowy conditions, snow will accumulate on the ground and rise along the outer wall of the first side wall 231; if the height of the ventilation opening 2311 is too low, it will be blocked or even blocked by snow accumulation. Therefore, the height of the ventilation opening 2311 from the ground is at least greater than the distance H1, which can be obtained according to the above-described method for calculating the height to prevent snow accumulation.

[0083] Alternatively, in some embodiments, another nuclear power plant building 23 is located adjacent to the nuclear power plant building 23, situated on one side of the first side wall 231 of the nuclear power plant building 23, and its height is less than that of the nuclear power plant building 23. In snowy conditions, snow will accumulate on the top surface (roof) of the other nuclear power plant building 23 and rise upwards along the outer wall of the first side wall 231; if the height of the ventilation opening 2311 is too low, it will be blocked or even sealed off by the accumulated snow. Therefore, the minimum height of the ventilation opening 2311 from the top surface of the other nuclear power plant building 23 can be obtained according to the above-described method for calculating the height to prevent snow accumulation.

[0084] Alternatively, in some embodiments, the roof walls of the nuclear power plant building 23 are stepped, forming a high-roof building 11 and a low-roof building 12 below the high-roof building. The wall 111 of the high-roof building 11 facing the low-roof building 12 is the first side wall 231. In snowy conditions, snow will accumulate on the top surface (roof) of the low-roof building 12 and rise upwards along the outer wall of the first side wall 231. If the height of the ventilation opening 2311 is too low, it will be blocked or even blocked by the snow accumulation. Therefore, the minimum height of the ventilation opening 2311 from the top surface of the low-roof building 12 can be obtained according to the above-described method for calculating the height to prevent snow accumulation.

[0085] See Figure 3 The present invention also constructs a nuclear power plant protection system, which can be used to protect safety-grade items arranged within the nuclear power plant building 23, including ventilation systems 5 and process systems, etc. Of course, the protection system can also be used to protect other systems, which is not limited here.

[0086] In some embodiments, the nuclear power plant protection system includes a baffle 232 disposed on the outer wall of the first side wall 231 of the nuclear power plant building 23, for shielding the ventilation openings 2311 from rain, snow, and projectiles; the baffle 232 has a fixed end and a free end, the fixed end being fixed to the first side wall 231; the free end facing the top surface, and a gap is left between the free end and the top surface and the first side wall 231 respectively. This gap is used to prevent the ventilation effect of the ventilation openings 2311 from being excessively blocked by the baffle 232.

[0087] In some embodiments, the baffle 232 is L-shaped and may include a first parallel plate 2321 and a first vertical plate 2322 connected to the first parallel plate 2321. The first parallel plate 2321 is located on the first side wall 231 above the vent 2311, with one end (fixed end) vertically fixed to the first side wall 231 and the other end vertically connected to the upper end of the first vertical plate 2322. The surface of the first vertical plate 2322 is relative to the vent 2311, and the lower end (free end) of the first vertical plate 2322 is spaced apart from the top surface and the vent 2311.

[0088] The lower end of the baffle 232 forms an opening 2323 between itself and the first side wall 231. This opening 2323 is located below and connected to the ventilation opening 2311. Preferably, the height of the opening 2323 is set in the same way as that of the ventilation opening 2311. To prevent snow accumulation from blocking the opening 2323, the height of the opening 2323 from the top surface is at least greater than a distance H2, which can be obtained according to the above-described method for calculating the height to prevent snow accumulation.

[0089] Preferably, to ensure that the baffle 232 can better shield against rain, snow, and flying objects, the line connecting the lower end of the baffle 232 to the lowest point of the vent 2311 is set to form an angle α with the plane where the first vertical plate 2322 is located; the angle α is between 20° and 40°. Preferably, the angle α is 30°.

[0090] See Figure 3 In some embodiments, the nuclear power plant protection system also includes a passive shock wave valve 4, which is used to isolate the ventilation duct when the ventilation duct of the ventilation system 5 generates a negative pressure or overpressure exceeding a preset value.

[0091] Understandably, when a positive pressure shock wave acts on the valve leaf of the passive shock wave valve 4, the valve leaf overcomes the resistance and moves to one side of the valve body of the passive shock wave valve 4. With the cooperation of the valve leaf and the valve body, the internal and external channels of the ventilation duct are blocked. When a negative pressure shock wave or negative pressure acts on the valve leaf, the valve leaf overcomes the resistance and moves to the other side of the valve body, closing with the valve body and blocking the internal and external channels of the ventilation duct. During normal ventilation, when the positive and negative pressure forces disappear, the valve leaf returns to the middle position, and the ventilation duct remains unobstructed.

[0092] In some embodiments, the design of the passive shock wave valve 4 needs to meet the design benchmarks for tornadoes and explosion shock waves in third-generation nuclear power plants, so that the passive shock wave valve 4 can quickly isolate and block the impact of external disasters on the items inside the nuclear power plant building 23 when tornadoes or explosion shock waves occur.

[0093] Considering the impact of tornadoes, the passive shock wave valve 4 needs to meet the following baseline conditions: maximum design wind speed: 80 m / s; maximum rotational wind speed: 62.0 m / s; maximum translational wind speed: 18.0 m / s; total pressure drop: 51.5 hPa; maximum pressure drop rate: 9.5 hPa / s; maximum projectile velocity: 28.0 m / s.

[0094] Considering the impact of the explosion shock wave, the passive shock wave resistant valve 4 needs to meet the requirements of a stepped pre-triangular wave with an overpressure of 20 kPa and a duration of 300 ms; and the valve closing time needs to be ≤10 ms when subjected to the design shock wave pressure, and ≤500 ms when subjected to a tornado.

[0095] See Figure 3 In some embodiments, the nuclear power plant protection system also includes an active isolation valve 3 for connecting the ventilation system 5, the active isolation valve 3 for isolating the ventilation ducts of the ventilation system 5 in the event of a failure of the ventilation system 5.

[0096] Understandably, in cold environments, such as winter operating conditions in northern nuclear power plants, when ventilation system 5 shuts down or its fresh air heating function is lost, in order to prevent cold air from penetrating and causing freezing risks to items inside the nuclear power plant building 23, the electric isolation valve is automatically triggered to isolate the ventilation duct of ventilation system 5.

[0097] In summary, the nuclear power plant protection system of the present invention can ensure the stable operation of the ventilation system 5 under the conditions of design reference, in the event of external disasters such as tornadoes, tornado-generated projectiles, and blast shock waves.

[0098] Secondly, in the event of ventilation system 5 shutting down and extreme rain, snow and low temperatures, not only can the factory boundary be automatically isolated to prevent cold air from penetrating and freezing the factory, but the ventilation openings 2311 and openings 2323 at the factory boundary will not be blocked by snow.

[0099] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A method for calculating the height of snow accumulation prevention, characterized in that, The snow pile refers to the snow accumulated around the perimeter of a wall standing on a snow-covered surface, and the height calculation method includes the following steps: S1: Obtain the length of the snow surface in the horizontal direction away from the wall; S2: Based on the length of the snow surface and the snow load on the snow surface, the snow accumulation height on the windward side is obtained; S3: Obtain the uniformly distributed snow load thickness on the snow surface, and obtain the total snow accumulation height based on the uniformly distributed snow load thickness and the snow accumulation height on the windward side; S4: Based on the total height of the snow pile, output the minimum height that the target object on the wall should be set at.

2. The method for calculating the height of snow accumulation prevention according to claim 1, characterized in that, In step S2, the snow accumulation height on the windward side is calculated according to formula a; formula a is: Among them, h d W refers to the height of snow accumulation on the windward side. b P refers to the length of the snow-covered surface. g Refers to the snow load on the snow surface.

3. The method for calculating the height of snow accumulation prevention according to claim 1, characterized in that, The process of obtaining the uniformly distributed snow load thickness on the snow surface includes: calculating the uniformly distributed snow load thickness according to formula b. The relation b is: Among them, h b P refers to the thickness of the uniformly distributed snow load. g The term refers to the snow load on the snow surface, ρ refers to the snow density, and g refers to the acceleration due to gravity.

4. The method for calculating the height of snow accumulation prevention according to claim 1, characterized in that, The process of obtaining the uniformly distributed snow load thickness on the snow surface includes: The uniformly distributed snow load thickness is obtained based on the snow accumulation height on the windward side.

5. A snow-accumulation prevention height calculation system, characterized in that, The step of implementing the height calculation method for preventing snow accumulation according to any one of claims 1 to 4, wherein the height calculation system comprises: The first acquisition module is used to acquire the length of the snow surface in the horizontal direction away from the wall; The first calculation module is used to obtain the snow accumulation height on the windward side based on the length of the snow surface and the snow load on the snow surface; The second calculation module is used to obtain the uniformly distributed snow load thickness on the snow surface, and to obtain the total snow accumulation height based on the uniformly distributed snow load thickness and the snow accumulation height on the windward side. The output module is used to output the minimum height that the target object on the wall should be set at, based on the total height of the snow pile.

6. A ventilation system arranged inside a nuclear power plant building, wherein the ventilation outlet of the ventilation system is installed on a first side wall of the nuclear power plant building; the first side wall is provided with a top surface connected to its outer wall surface and located below the ventilation outlet; the top surface includes the ground or the roof of a building; Its features are, The height of the vent from the top surface is at least greater than the distance H1, which can be obtained by the height calculation method for preventing snow accumulation according to any one of claims 1 to 4.

7. A nuclear power plant protection system for protecting safety-grade items arranged within a nuclear power plant building, the safety-grade items including a ventilation system, the nuclear power plant building including a vertical first side wall, the ventilation opening of the ventilation system being disposed on the first side wall, and the first side wall also having a top surface connected to its outer wall surface and located below the ventilation opening; Its features are, The nuclear power plant protection system includes a baffle for shielding the ventilation opening from foreign objects; the baffle is located outside the first side wall, and the minimum height of the baffle from the top surface is at least greater than a distance H2, wherein the distance H2 is obtained by the snow-blocking height calculation method according to any one of claims 1 to 4.

8. The nuclear power plant protection system according to claim 7, characterized in that, The baffle has a fixed end and a free end. The fixed end is fixed to the first side wall. The free end faces the top surface and is located below the vent, with a gap between it and the top surface and the first side wall.

9. The nuclear power plant protection system according to claim 8, characterized in that, The baffle includes a first parallel plate fixed at one end to the first side wall and a first vertical plate connected to the other end of the first parallel plate; The first parallel plate is positioned above the ventilation opening on the first side wall, and the surface of the first vertical plate is opposite to the ventilation opening.

10. The nuclear power plant protection system according to claim 9, characterized in that, The baffle is L-shaped, with one end of the first parallel plate vertically fixed to the first side wall and the other end of the first parallel plate vertically connected to the first vertical plate.

11. The nuclear power plant protection system according to claim 10, characterized in that, The line connecting the lower end of the first vertical plate to the lowest point of the vent forms an angle α with the plane where the first vertical plate is located; the angle α is between 20° and 40°.

12. The nuclear power plant protection system according to claim 8, characterized in that, It also includes a passive shock wave valve for connecting the ventilation system, which isolates the ventilation duct when the ventilation duct of the ventilation system generates a negative pressure or overpressure exceeding a preset value.

13. The nuclear power plant protection system according to claim 8, characterized in that, It also includes a powered isolation valve for connecting the ventilation system, which isolates the ventilation ducts of the ventilation system in the event of a ventilation system failure.

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