JPS6130816B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mixer diffuser for mixing a gaseous medium and a liquid medium, in particular a mixer diffuser used for controlling the heat and pressure energy resulting from an accidental nuclear reaction inside a nuclear reactor.・This is related to differential users.

Pressurized or boiling water type nuclear reaction systems are generally enclosed with secondary or steam vessel structures designed to withstand the maximum pressures that may occur as a result of a reactor accident. This type of accident results from a rupture of a cooling line or reaction vessel caused by sudden evaporation of the water refrigerant. There is also the possibility of hydrogen gas being released due to chemical reactions between the shell material and metal cladding and high pressure water. In any case, it is essential that such gases and vapors are accommodated in the reactor and that the pressure is reduced so as not to exceed limits predetermined by its structural design. be. The substances contained in some new nuclear fuels and in all nuclear fuels after inactivation are harmful to animals, plants, etc. Therefore, the release of these substances into the environment in the event of a serious reactor accident must be prevented.

The most serious and likely reactor accident is the rupture of the reaction pressure vessel or the main refrigerant passageway connected to the vessel, involving an exothermic chemical reaction between the fuel and the refrigerant, moderator, or other materials that may be present. It is generally thought that. The energy released during this type of accident is highly dependent on the amount and maximum temperature of the refrigerant, and significant amounts of vapor are produced containing gaseous fission products such as halogens and rare gases. be done. The safety of nuclear reactors is such that, in the event of an accident involving the release of radioactive fission products, all contained gases, liquids, and solids are contained in a container that is safe from leakage until their radioactive levels are substantially reduced. It relies on the principle that

In nuclear power generation equipment that generates large amounts of electric power, it is difficult to completely contain excess pressure.
Some must be dissipated. The most common solution to the containment problem is to form a vessel around the reactor and provide a preliminary cooling system with sufficient volume to hold the cooling water jetting out of the large cracks under suitable pressure. It is to form.

Conventionally, the reactor is internally connected to the reactor;
A torus-shaped pressure vessel that is approximately half filled with water has been put into practical use in order to condense excess water vapor. This type of monolithic torus or donut-shaped vessel is a very large tank structure, with typical tanks measuring 30 feet in cross-sectional diameter and 109 feet in centerline diameter. The torus-shaped vessel is placed in a hole or holding well surrounding the drying hole in the reactor and is connected to the drying hole vessel by means of a combination of vents consisting of headers and down pipes. There is. In another conventional type, the pressure vessel consists of a plurality of spherical pressure tanks connected to a drying hole by a header and a downcomer or large closed chamber located on the underside of the reactor.

In all conventional pressure chamber arrangements of this type, water vapor and other products in the event of a reactor accident are transported into the pressure chamber through headers and downcomers that communicate below the water level in the pressure vessel. It is removed. The water in the pressure chamber condenses and cools the water vapor to an internal pressure that does not exceed the design limits of the chamber.

Additionally, nuclear power plants typically include a steam relief valve that operates to release excess steam pressure from the cooling line when a rapid pressure increase occurs. Typically, the exhaust pipe of the water vapor relief valve communicates with the pressure chamber so that the water vapor is rapidly condensed. These relief valves are required to have their operability inspected at least once a year.

In a typical nuclear power plant, the dry well containment vessel has a volume on the order of 260,000 cubic feet.
In the event of an accident, significant amounts of air and water vapor are released into the pressure vessel through the headers and downcomers. This large volume of air and water vapor, together with the air already in the piping, is suddenly released into the deep part of the pressure chamber or its bottom, forming a kind of air layer that completely drains the water above it. Lift up to compress the air above the water. In a torus-shaped pressure chamber, the water is calculated to hit the top of the torus at a rate of 25 feet per second, causing significant damage to the expansion bellows and other equipment installed on top of the torus. Furthermore, the actual kinetic energy of the large volume of water striking the top of the pressure chamber physically displaces the pressure chamber, causing damage due to the displacement potential resulting in rupture, ejection of material containing nuclear material, etc.

Similar to nuclear power generation, conventional thermal power plants are equipped with a number of pressure relief valves that release high pressure steam during rapid pressure increases. Suppression and dissipation of noise and thermal energy during operation of this pressure relief valve is desirable. Moreover, in various industrial operations it is desirable to produce rapid and effective mixing of gaseous and liquid media.

Therefore, the provision of a mixer diffuser capable of diffusing or dissipating the energy generated as a result of a reactor accident or the incident energy due to the actuation of a water vapor pressure relief valve would be a welcome advance in this type of field. can bring. Also, providing a mixer diffuser capable of rapidly and effectively mixing gaseous and liquid media in various industrial fields could bring further advances in this type of field.

According to the invention, a mixer diffuser for diffusing and condensing water vapor ejected from the end of a hollow pipe extending into water has a conical buttful member with an inclined wall extending from a circular base to the top. . The top of this conical member is located within the open end of the pipe. The annular skirt member has a first open end having a first diameter slightly larger than the diameter of the pipe and a second open end having a second diameter larger than the first diameter, and the annular skirt member and are positioned around the pipe to form an annular opening between the edge of the first open end of the skirt member and the pipe. The second open end of the skirt member extends beyond the open end of the pipe that adjoins the circular base of the conical member. Means are provided for attaching the cone and skirt member to the end of the pipe. As water vapor is ejected from the end of the pipe, it flows against and beyond the conical member, and as it passes over the edge of the open end of the pipe, water is sucked through the annular opening. It mixes with water vapor to subdivide it into a large number of bubbles that are more easily condensed.

The invention has particular application in nuclear power generation systems. This type of nuclear power generation system includes a nuclear reactor, a sealed dry hole vessel surrounding the reactor,
a cooling water supply circulating around the reactor and heated by the reactor; at least one pressure chamber;
A downcomer tube extends into the pressure chamber and has at least one open end opening below the water surface of the pressure chamber.

An improved mixer diffuser used in connection with this type of nuclear power plant includes a conical member having a top and a bottom, the top of which is located within the open end of a downcomer extending below the water surface of the pressure chamber. while the circular bottom is located outside the open end of the downcomer. An annular skirt member having a first open end having a first diameter slightly larger than the diameter of the downpipe and a second open end having a second diameter larger than the first diameter. The first open end is positioned about and above the open end of the downcomer so that an annular opening is formed between the edge of the downcomer and the open end of the skirt member. . The second open end of the skirt member is disposed below the open end of the downcomer contiguous to the circular base of the conical member.

Means are provided for attaching the skirt member and cone member to the downcomer pipe.

During a nuclear reactor accident, when high-pressure water vapor, air or radioactive material is ejected through the downpipe, these materials mix with the water sucked in through the annular opening and diffuse into the pressure chamber. It is condensed.

The first object of the invention is therefore to provide a mixer for use in nuclear power reactors capable of dissipating the energy generated during a nuclear reactor accident or when a pressure relief valve is actuated. - Providing a differential user structure.

Another object of the invention is to provide an apparatus that allows rapid and effective mixing of gaseous media with liquid media.

Furthermore, another object of the present invention is to provide a mixer/diffuser capable of diffusing and condensing water vapor ejected from the open end of a pipe extending below the water surface.

Another object of the invention is to provide a mixer diffuser capable of dissipating heat, pressure and noise energy generated by the rapid release of high pressure gaseous media.

The above and other objects, advantages and details thereof of the present invention will be described below, and examples of the invention, including but not limited to, are illustrated in the accompanying drawings by way of illustration and without limitation. There is.

Referring to FIGS. 1 and 2, a known power plant 10 is illustrated. Power generation plant 10
It consists of a multi-storey building 12 having a roof 14, walls 16, a refueling room 18, a crane 20, a control room 22 and various individually non-identical rooms necessary for the plant. A nuclear reaction vessel 24 is provided inside the building 12 and contains a nuclear reaction material (not specifically shown). Partially surrounding the nuclear reaction vessel 24 is a shield 26 . Completely surrounding the nuclear reaction vessel 24 is a light bulb-shaped storage chamber 28 with a drying hole 30 formed therein. The storage chamber 28 is substantially surrounded by a concrete base 32 forming the foundation of the building 12. A drying hole 3 connected to the bottom of the storage chamber 28
0 through an opening 34 is a hollow header pipe 36. The header pipe 36 has a torus-shaped pressure chamber 38 partially filled with water.
penetrates the wall of. The header pipe 36 is connected to a torus-shaped pipe 42 communicating therewith. This pipe 42 extends all the way around the inside of the pressure chamber 38 , and a plurality of down conduits 44 are connected and communicated with the torus-shaped pipe 42 and extend below the water surface 40 . A continuous hollow conduit is thus formed from the drying hole 30 by the header pipe 36, the torus-shaped pipe 42 and the downconduit 44. This down conduit 4
Attached to the end of 4 is a mixer diffuser 46 according to the present invention.

Penetrating the wall of the storage chamber 28 and reaching the drying hole 30 are cooling pipes 48 , 50 that circulate a coolant such as water around the nuclear reaction vessel 24 . The refrigerant is heated by the reactor to perform the heat exchange necessary to generate electrical energy. Pipes 48, 50 are connected to a heat exchanger (not shown) for heating the secondary cooling water to generate water vapor for the generation of electrical energy. Refrigerant circulated through pipes 48, 50 is recirculated around nuclear reactor vessel 24 so that there is no possibility of release of contaminated refrigerant.

FIG. 3 shows another well-known nuclear power generation system. The storage container structure 100 is preferably made of reinforced concrete;
And its inner surface is covered with a steel lining 102. An inlet opening 104 is formed through the lower wall of containment structure 100 and is closed by a concrete door 106 . Containment structure 100 provides an impermeable barrier to prevent contaminants from entering the atmosphere, as is well known in the art.

Inside the containment vessel 100 is a cylindrical space having an outer diameter smaller than the space defined by the steel liner 102 on the inner circumference of the containment vessel 100 such that an annular space 112 surrounds the entire housing 110. have

A central compartment 114 surrounds the nuclear reactor 108. Side chamber 116 houses a steam generator 118 suitably interconnected with conduit 120 for circulating refrigerant around reactor 108 . The reactor housing structure 110 forms a lower pressure chamber 122 within which water 124 is placed. The radially distributed inlet openings 126 connect the pressure chamber 122 and the annular space 112.
communicate with. Further, communication between the central compartment 114 and the pressure chamber 122 is provided by a plurality (typically 16) of down conduits 128 that define openings 130 in the wall of the central compartment 114. communicated through. The walls 132 and 134 of the pressure chamber 122 constitute a barrier to the passage of gas and water vapor therethrough. Attached to the end of downconduit 128 is a mixer diffuser 46 according to the present invention. A pressure relief valve 121 is attached to conduit 120. When pressure builds up in conduit 120, pressure relief valve 121 releases steam pressure into pressure chamber 122 via downpipe 129.

4 and 5 illustrate yet another known nuclear reactor storage structure. This storage structure is similar to that shown in FIG. 1, except that a plurality of spherical pressure chambers 150 are provided instead of the torus-shaped pressure chamber. The storage chamber 152 houses a nuclear reactor (not shown), and a drop from the bottom of the chamber 152 passes through its wall and reaches below the surface of water 158 contained in the pressure chamber 150. A curved header pipe 154 extends to form a conduit 156. A mixer diffuser 46 according to the present invention is attached to the lower end of the down conduit 156.

For nuclear reactors of the type illustrated in Figures 1 through 5, the most likely accidents are loss of refrigerant,
This was a rupture of the primary cooling system, accompanied by melting of the core and release of radioactive materials. A rupture in the cooling channel fills the storage chamber with water vapor with a rapid increase in pressure. This rapid rise in vapor pressure in the storage chamber causes the air in the header and down conduit to be rapidly and rapidly reduced downward in opposition to the combined pressure of water pressure and air pressure in the pressure chamber. In a typical nuclear power plant, the headers and downcomers have extremely large diameters. Also, the down pipes are extremely numerous. The typical diameter of this type of downcomer is 24 inches, with the header having a much larger diameter on the order of 56 inches. Therefore, in a nuclear reactor accident, a large volume of air is suddenly forced down through the header and downcomer and released deep into the interior of the pressure chamber or at its bottom, and the air forms a layer. It lifts all the water and compresses the air above the water surface. With the reactor configuration shown in Figure 1, water is expected to strike the top of the torus at high speeds on the order of 25 feet per second. The kinetic energy of the large mass of water striking the top of this toroidal pressure chamber causes significant damage to the system resulting in the dissipation of pollutants into the atmosphere.

Similarly, in the nuclear power plant structure shown in FIG.
28 extends 18 feet below the water level in pressure chamber 122, as does the pipe from the main steam relief valve. Typically, the pressure chamber 1 shown in FIG.
22 has a diameter of about 90 feet and is filled with water to a depth of about 30 feet. Therefore, in the event of a nuclear reactor accident or actuation of the main steam relief valve, an 18-foot column of water stuck at the bottom of the pipes would be destroyed by compressed air and gas in each of the 16 downpipes. being pushed down rapidly. When air blows out from the bottom of the down conduit, 500~
A large bubble is formed with a high pressure of about 550 psi, and the bubble begins to expand rapidly. The inertia of water is
Even after the air and water pressures are equalized, the water continues to move, thereby creating a negative pressure on the air bubbles. These pressure fluctuations occur at a rate of about 8 cycles per second, resulting in extremely strong vibrating forces acting on the walls of the pressure chamber. And in extreme cases, the vibration or folding forces can cause severe damage to the entire building structure.

Additionally, a more serious problem called "chugging" is created when water vapor is ejected from the end of the downconduit. Chugging is a shock caused by pressure waves generated when a pocket of water vapor condenses and collapses, forcing water to rush to fill the space. This chugging gives the water a strong swirling effect, causing the water to be heated by the steam and reducing the condensation efficiency.

To overcome the above problems, a mixer diffuser according to the invention is mounted at the end of a downconduit that reaches deep underwater in a pressure chamber.

As shown in FIG. 6, the mixer diffuser 46 according to the present invention has a basically circular bottom 162
and a conical buttful member 160 having an inclined curved wall 164 extending toward a top portion 166. Hollow conduit 168 corresponds to either downconduit 44 in FIG. 1, 128 or 129 in FIG. 2, or 156 in FIG. The conduit also corresponds to any hollow conduit through which a high-pressure gaseous medium is jetted. The lower end 170 of conduit 168 is located below the level of liquid medium 172, which corresponds to the water in the pressure chamber shown in FIGS. 1-5. However, liquid medium 1
Any liquid medium capable of suitably dissipating energy and condensing water vapor can be used as 72.

The conically shaped buffle member 160 has a top portion 166 that extends between the lower edge 170 of the conduit 168 and the inclined wall 160 of the buffle member 160.
The end of the conduit 168 is mounted by a displacement rod 174 so as to project slightly into the end of the conduit 168 so as to form an annular inlet 176 therebetween. Displacement rod 174 is attached to conduit 168 and conical buffle 160 by suitable means such as welding.

Additionally, the outer side of the displacement rod 174 is attached adjacent to the end of the conduit 168 from a small first open end 182 to a second large open end 1.
Skirt member 178 has an integral sloped wall 180 sloped at 84. First open end 18
2 has a diameter that is larger than the diameter of conduit 168 and substantially larger than the circumference formed by displacement rod 174 . The skirt member 178 is the displacement rod 17
4 by suitable means such as welding, and an annular opening 186 is attached to the wall of the conduit 168 and the conduit 16
An annular opening 186 is formed between the edge 182 of the first open end of the skirt member 178 around the circumference of the skirt member 178 .

As air, water vapor, or other gaseous medium descends within conduit 168, as indicated by arrow A in FIG.
8 and the lower portion 170. air,
As water vapor or other gaseous medium passes through passageway 176, it undergoes a transfer of mass and momentum that draws liquid medium 172 through annular opening 186, as shown by arrow C in FIG. This suction action causes the air, water vapor, or other gaseous medium to mix in an agitated flow with the liquid medium sucked through the annular opening 186 before being ejected from the second open end 184 of the skirt member 178 . Therefore, the gas medium and the liquid medium are
4 and the inner wall 180 of the skirt member 178, and by the time the mixture is discharged from the second open end 184, the air, water vapor or other gaseous medium is actually liquid. It is mixed with a medium and subdivided into a large number of microscopic bubbles. These microscopic bubbles allow rapid dissipation of pressure energy and condensation of water vapor, thereby eliminating the problems described above. That is, the liquid medium 172 is not lifted upwards and pressure oscillations and chugging can actually be reduced to the extent that it does not result in any damage to the pressure chamber. If instead of a single large vibrating bubble of air and water vapor being ejected from the end of conduit 168, a large number of fine bubbles would be ejected, and the bubbles vibrating at different frequencies would expand and contract. The vibration forces caused by the bubbles cancel each other out and attenuate each other. Furthermore, as a result of the fine bubbles having a larger surface area than a single large bubble, water vapor released from the end of conduit 168 condenses much more rapidly.

The present invention reduces other problems associated with the release of high pressure gaseous media from the ends of conduits. The gas ejected from this type of conduit is determined by Newton's second law:
However, the conical buttle 160 can reduce the downward force by providing an inclined surface against which some of the gas acts. Furthermore, the thrust is further reduced by the presence of an agitating mixing action between the conical buffling member 160 and the skirt member 178. Thus, the present invention avoids bending or damage to the conduit 168 that would otherwise occur. In the nuclear reaction system illustrated and described in Figures 1-4, the flexible bellows or inflatable joint can be damaged by extremely large upward thrusts. or at various connection points where rupture could occur.
Thus, the present invention can eliminate these potential damages as well.

It can be clearly understood that the invention can be put into practice in connection with a variety of different systems other than the nuclear power generation systems described above. For example, a conventionally known thermal power generation device using coal is equipped with a large number of steam pressure relief valves that operate to relieve abnormally high pressure in the system. If these pressure relief valves were to release pressure directly to the atmosphere, operation of the pressure relief valves would result in excessive noise, heat rise, and other undesirable effects. Therefore, the present invention is equally applicable to thermal power plants as described above. These pressure relief valves are connected to the conduit 168.
Pressure is released through a conduit below the water level of the pressure tank to dissipate heat and noise energy.

Another possible application of the invention is the known natural gas pipeline system. Pipelines of this type are typically vented under high pressure to remove fog droplets or other inclusions that may accumulate in the pipeline. Usually, this type of pipeline is directly discharged into the atmosphere, which not only causes extremely loud noise pollution, but also causes air pollution due to the pollutants in the discharged gas. This type of noise pollution is caused by gas pipeline companies reporting in local newspapers prior to this type of release that the noise associated with the release is extremely loud and can reach several miles around the point of release. It is so serious that a warning has to be posted to explain it. The invention can be applied by discharging through such conduits reaching deep underwater, for example in ponds or large tanks, thereby dissipating noise underwater and retaining pollutants in the water. can do.

Furthermore, the present invention can be put into practice as providing a means for effectively mixing any type of gaseous medium with any type of liquid medium, for example in industrial or chemical related fields. The present invention can provide an effective means by which a gas medium can be subdivided into a large number of fine bubbles that are easily absorbed into a liquid medium.

Various variations, changes or modifications of the invention are possible and the invention can be applied to a wide variety of different types of devices without departing from the spirit and scope of the invention as set forth in the claims. .

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a nuclear power plant showing an embodiment according to the present invention, FIG. 2 is a top sectional view of the above plant taken along line 2-2 in FIG. 1, and FIG. FIG. 4 is a side sectional view showing another embodiment of the nuclear power plant; FIG. 5 is a side perspective view showing another embodiment of the nuclear power plant; FIG. 5 shows the downpipe and 6 is a partial side sectional view of a preferred embodiment of the invention; FIG. 46...Mixer diffuser, 160...Conical buttful member (162...Circular bottom, 164...Slope wall, 166...Top), 168...Conduit (44, 12
8, 129, 156...downward conduit), 170...end of conduit, 174...displacement rod, 178...skirt member (180...inclined wall, 182...first open end, 18
4...second opening end), 186...annular opening.

Claims (1)

[Scope of Claims] 1. A diffuser for diffusing and condensing water vapor ejected from the end of a hollow pipe reaching water, the diffuser having a circular inclined wall extending from the bottom to the top, the top of which is connected to the pipe. a conical member located within an end of the pipe; a first open end having a first diameter slightly larger than the pipe; and a second open end having a second diameter larger than the first open end; The open end is located around the pipe and adjacent the open end to form an annular opening between the pipe and the first open end, and the second open end is an annular opening extending beyond the end of the pipe. a skirt member and means for attaching the conical member and the skirt member to the end of the pipe, wherein water vapor ejected from the pipe end mixes with water sucked in through the annular opening, and the water vapor is diffused and condensed. A mixer/diffuser designed to be used. 2 a nuclear reactor, a closed dry hole vessel surrounding the reactor, a refrigerant supply device for circulating a refrigerant around the reactor and heated by the reactor, partially filled with a predetermined amount of water; at least one pressure chamber having a first open end communicating with the drying hole;
and at least one downconduit having a second open end extending below the water level of the at least one pressure chamber, the improved mixer diffuser in a nuclear power plant having a top and a circular bottom. , the top being located within the second open end of the at least one downconduit reaching below the water surface in the at least one pressure chamber, and the circular bottom being located outside the second open end of the downconduit. a first open end having a first diameter greater than the diameter of the at least one downconduit, and a second open end having a second diameter greater than the first diameter; an open end positioned around the at least one downconduit and above the second open end thereof to define an annular opening between the at least one conduit and the first open end; an annular skirt member located below a second open end of the at least one downconduit; and means for attaching the skirt member and the conical buttful member to the at least one conduit; water vapor, air, and nuclear contaminants ejected at high pressure through at least one downconduit to mix with water sucked in through the annular opening to diffuse and condense the water vapor, air, and nuclear contaminants; Mixer/defuser.