Method of increasing safety against nuclear power plant explosions
Elastic membranes filled with helium absorb and disintegrate blast waves, addressing the inefficiencies of existing methods by reducing blast impact and maintaining dynamic load balance in industrial spaces.
Patent Information
- Application Number
- IR140150140003000734
- Authority / Receiving Office
- IR · IR
- Patent Type
- Patents
- Current Assignee / Owner
- Priority Date
- 2020-10-05
- Filing Date
- 2022-04-20
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2042-04-20
AI Technical Summary
Existing methods for reducing explosion impact in industrial spaces, such as nuclear power plants, using foam or porous materials are ineffective due to liquid-induced corrosion and increased weight load, and existing elastic membrane methods impose a static load.
Elastic membranes filled with non-flammable gas like helium are deployed in multiple layers to absorb and disintegrate the blast wave, using sensors to detect flammable gas concentrations and fill the membranes with helium upon detection, allowing the wave to propagate through an inert gas environment.
The method effectively reduces the blast wave's impact on walls by at least half, as demonstrated by experimental tests, minimizing corrosion and weight load while maintaining a dynamic load balance.
Smart Images
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Abstract
Description
Method for increasing safety against nuclear power plant explosions This invention relates to methods for reducing the effects of explosive charges in industrial spaces, including nuclear power plants and large chemical production facilities. Methods and devices for reducing the shock wave using foam or porous materials, but without the use of additional damping mechanisms, are known [1. VM Kudinov, BI Palamarchuk, B.Ye. Gelfand, SA Parameters of the shock wave during the explosion of an explosive charge in foam / / "Reports of the USSR Academy of Sciences". Vol. 228, 1974, 4. - pp. 555-558. 2. B.Ye. Gelfand, AV Gubanov, Ye.I. Timofeev Contact of air shock waves with a porous plate / / "Izvestia of the USSR Academy of Sciences, MZhG", 1983, 4, pp. 79-84]. However, the use of such an approach is not effective in industrial spaces, since the presence of liquid in the porous plate leads to the formation of high humidity and, as a result, corrosion, as well as an increase in the weight load on the walls and floor of the protected room. The closest method to the claimed invention in terms of purpose and set of essential features is the method of increasing explosion safety. In this method, to attenuate the explosion wave, barriers in the form of elastic membranes filled with a flame-resistant liquid are placed in front of the protected surface. This method is considered the main prototype. The disadvantage of the prototype, as well as other analogues, is the presence of a static and constant load on the walls and floor of the protected space. The purpose of the claimed invention is to improve explosion safety. The technical result of this invention is to reduce the impact of the blast wave created by the accidental explosion of a fuel-air mixture on the walls and floors of protected spaces. In order to achieve the stated technical result, the known method improves explosion safety by weakening the impact of a combustion wave or shock wave on the protected surface by placing barriers in the form of elastic membranes filled with a flame-resistant liquid in front of the protected surface. It is proposed to use a non-flammable gas to fill the membranes. The membranes themselves are made of a material that collapses during and under the influence of the movement of the front of the combustion wave or shock wave along the surface of the membranes. The membranes are filled with a non-flammable gas immediately after the detection of a flammable gas in a dangerous concentration in the space in front of the protected object. Helium is used to fill the elastic membranes as a non-flammable material. The elastic membranes in front of the protected surface are placed in at least two layers. Each layer of elastic membranes is located in the recess of the previous layer. To fill the elastic membranes, an air / helium mixture containing at least 50% helium is used as a non-flammable material. The air-filled membranes are placed face-up against the helium-filled membranes.The total thickness of the elastic membranes filled with non-flammable material along the surface normal to the protected surface is greater than the two critical diameters of explosion in free space for the stoichiometric composition mixture. The set of disclosed features makes it possible to achieve high efficiency of the method of reducing the explosive and intense thermal effect of the blast wave on flat and curved surfaces, which enclose the protected space. No combination of the claimed essential features was found in known methods for reducing blast impact on protected surfaces. The proposed method for reducing the effect of a blast wave on a protected surface is described in Figure 1 and Figure 2. Figure 1 shows a possible embodiment of the claimed method and Figure 2 shows a schematic diagram of a blast chamber in which the effect of shock wave attenuation has been experimentally tested. According to Figure 1, sensors 2 determine the concentration of explosive gas. A controller 3, which, if necessary, activates the gas supply mechanism 4, a cylinder for storing compressed gases 5; a gas distribution system 6; elastic membranes 7 and a compressor 8 are located in the protected room 1.The surfaces of the NPP spaces are protected against explosive loads as follows. Signals about the concentration of flammable gas, for example, hydrogen, in the protected room of the NPP are continuously transmitted from the sensor 2 to the controller 3. When the controller 3 detects an unacceptable concentration of flammable gas (in an emergency), the controller 3 gives a command to the gas supply mechanism 4, and the elastic membranes 7 are filled with non-flammable gas, such as helium, through the distribution system 6 and from the containers 5 (in Fig. 1, two layers of membranes are filled with non-flammable gas). If the concentration of flammable gas in the space 1 can be reduced to a safe level (for example, due to the operation of the ventilation system and the chemical oxidation system of flammable gas, not shown in the figures), the gas from the membranes 7 can be returned to the containers 5 for further use using the corresponding compressors. Therefore, the explosive charge protection system of spaces can be restored to its original state using elastic membranes with non-flammable (inert) gas.If explosive combustion occurs in space 1, the combustion wave (or shock wave) approaching the elastic membranes 7 will disintegrate them and continue its movement in a non-flammable (inert) gas environment, which will lead to a reduction in the effect of its force on the walls and, in particular, on the vault of space 1. The effectiveness of shock wave attenuation was tested in an experiment with a large explosion in a volume of hydrogen-air mixture in a spherical explosion chamber 9 with a diameter of 12 m, the schematic of which is shown in Fig. 2. The pre-mixed flammable mixture was pumped into a latex membrane 10 (probe balloon) with a volume of up to 40 cubic meters. Combustion or explosion was initiated in the center by a dense explosive charge 11. Pressure sensors 12 D1-4 and ionization sensors 12 I1-4 were located inside the membrane and somewhat outside it. In relation to external objects, which are represented in the simplest case by the limiting surfaces, the spherical volume 10 located in the area near the wall simulates the accumulation of a flammable hydrogen-air mixture in the interior of the nuclear power plant. To record the parameters of the explosive charge, four pressure sensors 13 were placed near the surface of the explosive chamber, which are shown in the right part of the diagram in Fig. 2. RSV113 sensors were used as pressure sensors 13, which were installed in a steel plate 6 mm thick and with a surface area of 0.52 x 0.65 m2 (not shown in the figure). Elastic membranes 7 filled with helium or air and having a gas layer thickness of 0.6 m or filled with a two-layer air-helium gas system with a total gas layer thickness of 0.6 m and a layer thickness ratio of 1:1 were installed on some of the sensors 13. In the experiments, the pressure recorded by the sensors 13 was compared for two types – i.e. with and without protective membranes in place 7, as shown in Figure 2 . Differential pressure comparison table Sensor in plate covered with inertizer, ΔP, bar Sensor in plate covered with inertizer 35-40 Type and thickness of inertizer layer ΔP, bar Air, 0.6 m 14.9 Helium, 0.6 m 4.7 Air Helium 0.6 m (1 / 1) 5.4 These tests have shown that elastic membranes filled with helium provide the best pressure reduction. The 0.6-meter thickness of the gas layer specified in the elastic membranes in the path of the blast wave propagation is at least twice the critical explosion diameter in free space for a hydrogen-air mixture with stoichiometric composition.
Claims
1. A method of providing explosion safety for nuclear power plants, comprising placing obstructions before a protected surface (1) in the form of elastic membranes (7) filled with a non-flammable gas, characterized in that the membranes (7) are made of a material that disintegrates during and under action of displacement of a front of a combustion wave or shock wave along a surface of the membranes (7), wherein the membranes (7) are filled with the non-flammable gas immediately after flammable gas is detected at a unacceptable concentration in a space in front of the protected object, wherein the elastic membranes (7) are placed before the protected surface (1) in at least two layers.
2. A method of claim 1, wherein helium is used as the non-flammable gas filling the elastic membranes (7).
3. A method of claim 1, wherein an air / helium mixture with a helium content of at least 50 vol. % is used as the non-flammable gas filling the elastic membranes (7).
4. A method of claim 2, wherein membranes filled with air are placed before the membranes (7) filled with helium.
5. A method of claim 1, wherein total thickness of the elastic membranes (7) filled with non-flammable gas along the normal to the protected surface (1) exceeds two critical detonation diameters in a free space for the stoichiometric mixture