JPH1172589A - Device for exhausting main steam relief safety valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhausting device of main steam relief safety valve improved in maintaining the soundness of the reactor containment and the blow efficiency by making the exhaust pipes common for a plurality of main steam relief safety valves and improving the arrangement and working capability of exhaust pipes by contriving the shapes of a quencher and blow holes, and by suppressing the pressure fluctuation generated in blowing steam, etc. SOLUTION: The exhaust device of main steam relief safety valve connects a plurality of main steam relief safety valves 3a automatically relieving at a set blow pressure in abnormal increase of pressure of a reactor to respective main steam pipes 2. The exhaust pipe 4a for introducing discharge steam to a suppression chamber 7 by connecting to each of main steam relief safety valves 3a is branched into a plurality of split exhaust pipes 11a and 11b in the suppression chamber 7 and connected to quenchers 8 blowing air and steam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a main steam release safety valve for preventing overpressure of a nuclear reactor provided in a main steam pipe in a boiling water nuclear power plant, and an exhaust device for a main steam release safety valve related to an exhaust pipe and the like. About.

[0002]

2. Description of the Related Art In a boiling water nuclear power plant, steam generated in a reactor pressure vessel 1 as a nuclear reactor is passed through a plurality of main steam pipes 2 as shown in a sectional view of a main part of FIG. The power is sent to a turbine system, and a turbine generator (not shown) is rotated to generate power (here, only one main steam pipe is shown).

[0003] Reactor pressure rises due to the operation of a nuclear power plant. To prevent excessive pressure rise in the reactor and maintain the integrity of the reactor pressure vessel 1,
A plurality of main steam safety relief valves (Main Steam Safety Relief Valv.
e, hereinafter abbreviated as MSSRV) 3a, 3b are installed (here, two are shown).

The MSSRVs 3a and 3b are connected to exhaust pipes 4a and 4b, respectively, and the ends of the MSSRVs 3a and 3b are located in a reactor containment vessel 5 constructed around the reactor pressure vessel 1.
It is connected to a quencher 8 installed at the bottom of a suppression chamber 7 formed at the lower part partitioned by a diamond from floor 6. Since the suppression pool water 9 is stored in the suppression chamber 7, the quencher 8 is always placed in the suppression pool water 9.

[0005] The plurality of MSSRVs 3a and 3b installed in the main steam pipe 2 are set to have different outlet pressures. When the reactor pressure excessively rises and reaches the outlet set pressure, the MSSRV 3a , 3b open automatically. As a result, the discharged steam is rapidly discharged from the quencher 8 in the suppression chamber 7 into the suppression pool water 9 through the exhaust pipes 4a and 4b, so that the reactor pressure vessel 1 is easily depressurized and the overpressure is reduced. Is prevented.

Since the set pressure of the MSSRVs 3a and 3b is different for each valve, when the reactor pressure rises, the MSSRV 3a with the set pressure at the low pressure side operates first, and then the high pressure side. MSSRV3b
It works in the order of. However, in many events, several of the MSSRVs 3a at the respective low-pressure side set pressures installed in the plurality of main steam pipes 2 are activated,
Because it is possible to prevent excessive pressure increase of the reactor,
All the valves of the low pressure side MSSRV3a and the high pressure side MSSRV3b hardly operate.

The steam discharged from the MSSRVs 3a and 3b passes through exhaust pipes 4a and 4b, respectively, protrudes from the quenchers 8, and is supplied to a plurality of arms 10 through a plurality of blowout holes. Water 9
The air is rapidly blown out and condensed together with the cooling by the suppression pool water 9.

[0008]

The above-mentioned MSSRV3a,
When the discharge steam from the main steam pipe 2 is blown out to the exhaust pipes 4a and 4b by the opening operation of 3b, the discharge steam flows from the quencher 8 into the suppression pool water 9 via the exhaust pipes 4a and 4b. To be blown out. However, the air accumulated in the exhaust pipes 4a and 4b before this is pushed by the steam and blown out into the suppression pool water 9, and thereafter the steam is blown out.

When the air is rapidly blown out of the quencher 8, a pressure fluctuation occurs in the suppression pool water 9, and when the steam blown out from the quencher 8 condenses in the suppression pool water 9, the pressure fluctuation also occurs. Occurs. This pressure fluctuation quickly propagates in the suppression pool water 9 and applies a load on the walls of the reactor containment vessel 5 that has a detrimental effect on soundness.

The exhaust pipes 4a and 4b installed in the reactor containment vessel 5 may be provided with a piping route for reducing the load applied to the exhaust pipes 4a and 4b when the MSSRVs 3a and 3b are blown out. , MSSRV3a,
It is necessary to set the piping route such that the blowing pressure of 3b is within the allowable value and the blowing capacity is secured.

However, the exhaust pipes 4a and 4b are
Since a dozen or so are generally installed in the same number as the number of a and 3b installed, in the reactor containment vessel 5 where many other important equipment and piping are installed, it is appropriate for all exhaust pipes. It is extremely difficult to set a proper piping route, and
There was a problem that the installation work became complicated.

Further, when air and steam are blown out from the quencher 8, the pressure loss of the arm 10 of the quencher 8 is increased because the flow path is longer at the tip end than at the center of the quencher 8. , The arm 10
It is difficult to blow out steam uniformly from each of the blowout holes (not shown), since the tip portion is smaller than the center portion,
If the blowout amount is imbalanced, the pressure reduction efficiency of the reactor pressure vessel 1 has been reduced.

An object of the present invention is to use a common exhaust pipe for a plurality of main steam release safety valves, to improve the arrangement and workability of the exhaust pipe by the shape of a quencher and a discharge hole, and to discharge air and steam. An object of the present invention is to provide an exhaust device for a main steam relief safety valve that suppresses pressure fluctuations that occur at the same time and maintains the integrity of the containment vessel and improves the blowing efficiency.

[0014]

According to a first aspect of the present invention, there is provided an exhaust system for a safety valve for a main steam relief valve, which is configured to automatically set a predetermined blow-out pressure when a reactor pressure is excessively increased. A plurality of main steam relief safety valves, which are opened in series, are connected to the plurality of main steam pipes, and a plurality of exhaust pipes connected to the respective main steam relief safety valves to guide the discharged steam to the suppression chamber are provided in the suppression chamber. It is characterized in that a quencher for blowing air and steam is connected to each of the branches.

The exhaust pipe connected to the main steam release safety valve is
Since it branched at the tip and connected to multiple quenchers,
When the air in the exhaust pipe and the steam discharged from the main steam relief safety valve are blown into the suppression chamber, the blowout amount per quencher decreases, so that the pressure fluctuation caused by the air blowout and the blown steam condensed. The pressure fluctuations that occur at the time are reduced, and the influence of each pressure fluctuation on the reactor containment vessel is reduced.

According to a second aspect of the present invention, there is provided an exhaust system for a main steam relief safety valve comprising a plurality of main steam relief safety valves which automatically open at a preset blow-out pressure when an excessive pressure rise of a nuclear reactor occurs. And an exhaust pipe connected to the plurality of main steam relief safety valves to guide discharged steam to the suppression chamber is connected to a common combined exhaust pipe at the upper part of the suppression chamber, and the combined exhaust pipe is connected to the main steam pipe. A quencher for blowing air and steam in the suppression chamber is connected to the tip of the quencher.

Since the exhaust pipes of the plurality of main steam relief safety valves are combined into a common combined exhaust pipe and guided to the suppression chamber, the number of exhaust pipes is reduced, and the arrangement and workability of the exhaust pipe in the suppression chamber are improved. I do.

According to a third aspect of the present invention, there is provided an exhaust system for a main steam release safety valve, comprising a plurality of main steam release safety valves which automatically open at a preset blow-out pressure when an excessive pressure rise of a reactor occurs. And an exhaust pipe connected to the plurality of main steam relief safety valves to guide discharged steam to the suppression chamber is connected to a common combined exhaust pipe at the upper part of the suppression chamber, and the combined exhaust pipe is connected to the main steam pipe. Is divided into a plurality of parts in the suppression chamber, and a quencher for blowing air and steam is connected to each of them.

By combining the exhaust pipes of the plurality of main steam relief safety valves into a common combined exhaust pipe, the number of exhaust pipes is reduced, the arrangement and workability in the suppression chamber are improved, and the common combined exhaust pipe is provided. Since a plurality of quenchers are connected to the pipe, the amount of air and steam blown out per quencher is reduced, the pressure fluctuation caused by blowing air from the quencher, and the pressure generated when the blown steam condenses Fluctuations are reduced, and the influence of each pressure fluctuation on the reactor containment is reduced.

According to a fourth aspect of the present invention, in the exhaust system for a main steam release safety valve according to the second or third aspect, when the pressure of the nuclear reactor rises excessively, it is automatically opened at a preset blow set pressure. A plurality of main steam relief safety valves are connected to each of a plurality of main steam pipes, and a plurality of main steam relief safety valves having mutually different blow-out set pressures are connected to a common combined exhaust pipe.

The plurality of main steam release safety valves connected to a common combined exhaust pipe through which the steam discharged from the plurality of main steam release safety valves collectively flows are set at different outlet pressures from each other. The combined exhaust pipe has a margin in the flow path with respect to the amount of steam discharged when the safety valve is opened. Therefore, the discharge speed of the air accumulated in the combined exhaust pipe from the quencher is reduced by the discharge steam from the low-pressure side main steam release safety valve, so that the generated pressure fluctuation is reduced and the integrity of the containment vessel is reduced. The effect is reduced.

According to a fifth aspect of the present invention, there is provided an exhaust system for a main steam release safety valve according to any one of the first to fourth aspects, wherein the exhaust pipe and the combined exhaust pipe are connected to the main steam release safety valve to guide discharged steam to the suppression chamber. In the quencher connected to the above, the arm protruding to the periphery and having a large number of blow holes in the axial direction is provided with an elevation angle at which the blow flow rate in each of the blow holes is equal or almost equal.

[0023] A large number of blow holes formed in an arm provided to protrude from the quencher have a difference in height in the vertical direction at an elevation angle provided in the arm, and a head difference due to suppression pool water occurs. Thereby, the blow-off hole near the base of the arm, the blow-out hole at the tip end, and the blow-out hole at an intermediate position thereof have the same flow rate of the blown air and steam despite the different pressure loss, and therefore have a high flow rate. It is blown out at the blowing efficiency.

According to a sixth aspect of the present invention, there is provided an exhaust system for a main steam release safety valve according to any one of the first to fourth aspects, wherein the exhaust pipe and the combined exhaust pipe are connected to the main steam release safety valve to guide discharged steam to the suppression chamber. In the quencher connected to the arm, the diameter of each outlet hole of the arm that protrudes to the periphery and has a number of outlet holes in the axial direction is such that the outlet flow rate in each outlet hole from the base of the arm toward the tip end is equal or almost equal. It is characterized in that it is made larger gradually.

The air and steam blown out from a large number of blowout holes of the arm provided so as to protrude from the quencher are such that the diameter of the blowout hole opened in the arm is small at the blowout hole near the base of the arm and large at the tip end portion. Also, the outlet hole at the intermediate position is provided with a hole having a size therebetween. For this reason, the air and steam blown out from each blowout hole are blown out with high blowout efficiency because the blowout flow rates are equal despite the pressure loss being different from each other.

[0026]

Embodiments of the present invention will be described with reference to the drawings. Note that the same components as those of the above-described related art are denoted by the same reference numerals, and detailed description thereof will be omitted. The first embodiment relates to claim 1 and, as shown in a sectional view of a main part of FIG. 1, sends steam generated in a reactor pressure vessel 1 to a turbine system through a plurality of main steam pipes 2. A turbine generator that does not rotate is used to generate power (here, only one main steam pipe is shown).

In the main steam pipe 2, the reactor pressure vessel 1
A plurality of MSSRVs 3a are installed in the vicinity of (only one is shown here), and the MSSRV 3a is connected to the exhaust pipe 4a. Multiple branch exhaust pipes 11
a and 11b, and one quencher 8 is connected to each (here, the case of two branches is shown).

Each of the quenchers 8 is installed at the bottom of a suppression chamber 7 formed at the lower part of the reactor containment vessel 5, and the suppression chamber 7 stores suppression pool water 9. Therefore, each of the quenchers 8 is always placed in the suppression pool water 9.

Next, the operation of the above configuration will be described. If for some reason the reactor pressure rises excessively, M
When the reactor pressure reaches the blowout set pressure, the SSRV 3a automatically opens and rapidly releases the steam in the reactor pressure vessel 1 via the main steam pipe 2 to the exhaust pipe 4a. Therefore, since the pressure of the reactor is reduced, a pressure increase is prevented, and the integrity of the reactor pressure vessel 1 is maintained.

At this time, the air accumulated in the exhaust pipe 4a is pushed by the discharge steam and passes through the exhaust pipe 4a.
It is separated by two branch exhaust pipes 11a and 11b, and is discharged from the two quenchers 8 into the suppression pool water 9 of the suppression chamber 7, and then steam is discharged.

As described above, since the exhaust pipe 4a of one MSSRV 3a is divided into two branch exhaust pipes 11a and 11b at the tip, the air accumulated in the exhaust pipe 4a and the air discharged from the MSSRV 3a are blown out. The amount of the discharged steam blown out per unit in the quencher 8 is greatly reduced.

As a result, the pressure fluctuations caused by the blowing of air from the quencher 8 and the pressure fluctuations generated when the discharged steam condenses are both reduced, so that the containment of the reactor receiving the pressure fluctuations is reduced. In the container 5, since the influence is small, good soundness can be maintained.

In the second embodiment, as shown in FIG. 2, the steam generated in the reactor pressure vessel 1 is supplied to a turbine system through a plurality of main steam pipes 2 as shown in the sectional view of the main part. The power is sent and a turbine generator (not shown) is rotated to generate power (here, only one main steam pipe is shown).

In the main steam pipe 2, the reactor pressure vessel 1
A plurality of MSSRVs 3a and 3b are installed in the vicinity of (only two are shown here).
The exhaust pipes 4a and 4b are connected to the exhaust pipes 4a and 4b, respectively. The two exhaust pipes 4a and 4b are put together at the upper part of the diaphragm floor 6 and connected to the common combined exhaust pipe 12.

Here, as an example, a case where two MSSRVs 3a, 3b installed in the same main steam pipe 2 are combined with two exhaust pipes 4a, 4b connected to each other is shown. There is also a configuration in which a plurality of exhaust pipes connected to a plurality of installed MSSRVs are merged, or a configuration in which a plurality of exhaust pipes connected to a plurality of MSSRVs installed in a plurality of different main steam pipes 2 are combined. Furthermore, this combined exhaust pipe 12
Is connected to one quencher 8 in the suppression chamber 7.

The quencher 8 is provided at the bottom of a suppression chamber 7 formed below the reactor containment vessel 5, and the suppression chamber 7 stores suppression pool water 9. The quencher 8 is always placed in the suppression pool water 9.

Next, the operation of the above configuration will be described. If for some reason the reactor pressure rises excessively, M
The SSRVs 3a and 3b open automatically when the reactor pressure reaches the blowout set pressure, and rapidly release the steam in the reactor pressure vessel 1 via the main steam pipe 2.
Therefore, since the pressure of the reactor is reduced, a pressure increase is prevented, and the integrity of the reactor pressure vessel 1 is maintained.

At this time, the air accumulated in the exhaust pipes 4a and 4b and the combined exhaust pipe 12 is pushed by the discharged steam, passes through the exhaust pipes 4a and 4b and the combined exhaust pipe 12, and is suppressed from the quencher 8 by the suppression. Released into the pool water 9, followed by steam. In addition, the one combined exhaust pipe 12
In the above, the two exhaust pipes 4a,
4b, the same flow area can be secured with a relatively small diameter of the expansion ratio, and the pressure loss is reduced and the mechanical strength is reduced as compared with the case of the two exhaust pipes 4a, 4b. Greatly obtained.

In this manner, a plurality of MSSRVs 3a,
3b exhaust from each exhaust pipe 4a, 4b to a common combined exhaust pipe
The exhaust pipe 4 provided in the suppression chamber 7 is led to the suppression chamber 7 in
By replacing a and 4b with the combined exhaust pipe 12, the number thereof can be greatly reduced while improving the function and strength. As a result, the arrangement of the exhaust pipe in the suppression chamber 7 is improved, so that an appropriate piping route can be easily set, the degree of freedom in design is increased, and the installation work is simplified.

The third embodiment relates to claim 3 and is a combination of the first embodiment and the second embodiment. As shown in the sectional view of the main part of FIG. The steam generated in the vessel 1 is sent to a turbine system via a plurality of main steam pipes 2, and a turbine generator (not shown) is rotated to generate electric power (here, only one main steam pipe is shown).

In the main steam pipe 2, the reactor pressure vessel 1
A plurality of MSSRVs 3a and 3b are installed in the vicinity of (only two are shown here).
a, 3b are connected to the exhaust pipes 4a, 4b, respectively. However, these two exhaust pipes 4a and 4b are combined together at the upper part of the diaphragm floor 6 to form a common combined exhaust pipe.
12 is connected to a plurality of branch exhaust pipes 11a, 11b in the suppression chamber 7.
And one quencher 8 is connected to each (here, two branches are shown).

Here, as an example, a case is shown in which two exhaust pipes 4a, 4b connected to two MSSRVs 3a, 3b installed in the same main steam pipe 2 are combined. A plurality of exhaust pipes connected to a plurality of MSSRVs installed in a plurality of MSSRVs connected to a common combined exhaust pipe, or an exhaust pipe connected to a plurality of MSSRVs installed in a plurality of different main steam pipes 2 There is also a configuration in which a plurality of are combined and connected to a common combined exhaust pipe.

Further, each of the quenchers 8 is installed at the bottom of a suppression chamber 7 formed below the reactor containment vessel 5, and the suppression chamber 7 stores a suppression pool water 9. Therefore, each of the quenchers 8 is always placed in the suppression pool water 9.

Next, the operation of the above configuration will be described. If for some reason the reactor pressure rises excessively, M
The SSRVs 3a and 3b open automatically when the reactor pressure reaches the blowout set pressure, and rapidly release the steam in the reactor pressure vessel 1 via the main steam pipe 2.
Therefore, since the pressure of the reactor is reduced, a pressure increase is prevented, and the integrity of the reactor pressure vessel 1 is maintained.

At this time, the air that has accumulated inside the exhaust pipes 4a and 4b, the combined exhaust pipe 12, and the plurality of branch exhaust pipes 11a and 11b is pushed by the discharged steam and is exhausted by the exhaust pipes 4a and 4b.
4b, through the combined exhaust pipe 12, and the branch exhaust pipes 11a and 11b, from a plurality of quenchers 8 to the suppression pool water 9.
Into which steam is released.

In this way, a plurality of MSSRVs 3a,
3b exhaust from each exhaust pipe 4a, 4b to a common combined exhaust pipe
As a result, the number of exhaust pipes 4a and 4b can be significantly reduced. Further, the arrangement of the exhaust pipe in the suppression chamber 7 is improved, so that an appropriate piping route can be easily set, the degree of freedom of design is expanded, and the installation work is simplified.

Further, by dividing into two branch exhaust pipes 11a and 11b at the end of the combined exhaust pipe 12 and leading them from the two quenchers 8 into the suppression pool water 9 in the suppression chamber 7, the exhaust pipes 4a and 4b are connected to each other. Merged exhaust pipe 12,
In addition, the amount of air accumulated in the branch exhaust pipes 11a and 11b and the amount of discharged steam blown out from the MSSRVs 3a and 3b per quencher 8 is reduced.

As a result, the pressure fluctuation caused by the blowing of air from the quencher 8 and the pressure fluctuation generated when the blown steam is condensed are all reduced, and the reactor containment vessel 5 is reduced via the suppression pool water 9. , And the soundness of the containment vessel 5 can be maintained satisfactorily.

The fourth embodiment relates to claim 4 and is a modification applied to the second and third embodiments.
4, for example, four main steam pipes 2 (No. 1 to No. 1) connected to the reactor pressure vessel 1 are shown.
Each 4), balloon set pressure from the low pressure side P ₁ until the high pressure side P _4, each four MSSRV3a ₁ ~3d
_{1, 3a 2 ~3d 2, 3a} 3 ~3d 3, 3a 4 ~3d 4
Is installed.

Each main steam pipe 2 (No. 1 to No.
In 4), each of four MSSRV3a ₁ ~3d _1, 3
The same applies to each of the main steam pipes 2 (No. 1 to No. _{4) with} respect to the set blowing pressures P _{1 to} P _{4 at} a _{2 to} 3d ₂ , 3a _{3 to} 3d ₃ , and 3a _{4 to} 3d ₄ . .

Here, as shown in FIGS. 2 and 3, each of the four MSSRVs 3a _{1 to} 3d ₁ , 3a ₂ to 3
For 3d ₂ , 3a _{3 to} 3d ₃ , 3a _{4 to} 3d ₄ , two MSSRVs and each exhaust pipe are combined into one combined exhaust pipe 12.
Let's take an example of connecting together.

In main steam pipe 2 (No. 1), MSSRV 3a ₁ (P ₁ ) and MSSR
V3c ₁ (P ₃ ), MSSRV 3b ₁ (P ₂ ) and M
Like the SSRV 3d ₁ (P ₄ ), the consolidation in the combined exhaust pipe 12 is configured by combining different outlet setting pressures.

That is, a plurality of MSSRVs connected to the same combined exhaust pipe 12 via a plurality of exhaust pipes are
Even if the main steam pipes 2 provided with the main steam pipes 2 are the same main steam pipe 2 or different main steam pipes 2, a configuration is adopted in which pipes having different blowing set pressures are combined.

As an example of this combination, in addition to the above, the MSSRV 3a in the main steam pipe 2 (No. 1)
₁ (P ₁ ), MSSRV3d ₁ (P ₄ ), and MSSR
V3b ₁ (P ₂ ) and MSSRV 3c ₁ (P ₃ ), and MSSRV 3a of main steam pipe 2 (No. 1)
₁ (P ₁ ) and MSSRV3c of main steam pipe 2 (No. 2)
₂ (P ₃ ) or MS of main steam pipe 2 (No. 1)
MS of SRV3a ₁ (P ₁ ) and main steam pipe 2 (No. 3)
There are many such as SRV3d ₃ (P ₄ ).

Next, the operation of the above configuration will be described. If for some reason the reactor pressure rises excessively, M
SSRV3a ₁ ~3d _1, when the reactor pressure respectively reaching the set pressure P ₁ to P ₄ blowout preset,
The steam in the reactor pressure vessel 1 is released quickly and automatically through the main steam pipe 2 in order.

[0056] In MSSRV3a ₁ and merged exhaust pipe 12 summarizes the MSSRV3c ₁ is, MSSRV3a ₁ and M
SSRV3c ₁ is blow set pressure each other P ₁ and P ₃
Because it is different as, MSSRV3a ₁ is first opened. Therefore, with an excessive rise in the reactor pressure, the MSSRV 3a1 on the low pressure side is _first opened,
The steam discharged from SRV3a _1, air that has been accumulated in the merging exhaust pipe 12 is blown from the quencher 8 in the suppression pool water 7.

The blowing speed at this time depends on the combined exhaust pipe 12
Has a flow path area that is equal to the amount of steam discharged from the two MSSRVs 3a ₁ and 3c _{1, so} that _one MSSRV 3a ₁ and 3c ₁
The flow rate of the steam discharged from 3a ₁ is decreased in merged exhaust pipe 12. Particularly, blow rate of air and discharge vapor has accumulated in the interior is slowed.

As a result, the pressure fluctuation caused by the blowing of the air from the quencher 8 and the pressure fluctuation generated when the blown steam is condensed are both reduced, and the reactor containment vessel 5 is suppressed via the suppression pool water 9. , And the soundness of the containment vessel 5 can be maintained satisfactorily. Further, the opening of MSSRV3a ₁ of the low-pressure side (P ₁₎ is, MSSRV3a ₂ ~ other steam pipe 2 (not shown) (No.2~No.4)
Also in 3a _4, the reactor is depressurized performed substantially simultaneously.

Therefore, normally, the low pressure side MSSRV3
Simultaneously with the opening of a ₁ ~3a _4, each MS of the high-pressure side (P ₃₎
SRV3b ₁ ~3b ₄ it is rare that a state of is opened together, also a plurality of exhaust pipes 4a for connecting the aperture of merging exhaust pipe 12, by the flow area to meet the total flow in 4b, mechanical strength together to obtain large yields sufficient margin in the flow area at the time of opening of only MSSRV3a ₁ on the low-pressure side.

As a result, the pressure reduction function of the nuclear reactor and the mechanical strength of the exhaust pipe are improved, the number of exhaust pipes is greatly reduced, the arrangement of the exhaust pipes in the suppression chamber 7 is improved, and an appropriate piping route is improved. Setting can be facilitated, design flexibility can be expanded, and installation work can be simplified.

The fifth embodiment relates to claim 5 and relates to a quencher. As shown in the front view of FIG. 5, a plurality of arms 10 provided in a quencher 13 have a large number of blowout holes 14a, 14b and the elevation angle θ is provided.

When the arm 10 is installed horizontally, the elevation angle θ provided to the arm 10 is a distance l from the base.
Pressure loss when air and steam are blown out from the blowout hole 14a at the position L, and the blowout hole 14b at the position L at a distance L from the base.
Is set so that the difference in pressure loss at the time of blowing from the nozzle is equal to or almost equal to the pressure loss due to the head difference 15 between L cos θ and l cos θ. Thereby, whether the blowout flow rate from the blowout hole 14a is equal to the blowout flow rate from the blowout hole 14b,
It is configured to be approximately equal.

Next, the operation of the above configuration will be described. The air or steam flowing down the exhaust pipes 4a, 4b, 12 and flowing through the arm 10 of the quencher 13 into the suppression pool water 9 from the outlet holes 14a, 14b is compressed at a pressure corresponding to the moving distance in the arm 10. Loss occurs. For this reason, when the diameters of the blowout holes 14a and 14b are the same, a difference occurs in the blowout flow rate between the blowout hole 14a at a distance 1 close to the base of the arm 10 and the blowout hole 14b at a long distance L, and the flow rate of the blowout hole 14a is reduced. Is larger than the blowout hole 14b.

However, since the arm 10 is provided with the elevation angle θ, there is a difference in the vertical position between the blowout hole 14a and the blowout hole 14b, and the quencher 13 is always in the suppression pool water 9. Therefore, the difference between the vertical positions is a head difference 15 caused by the suppression pool water 9.

Accordingly, since the distance between the base of the arm 10 and the distance L from the base of the outlet hole 14a and the outlet hole 14b are equal to each other, the pressure loss of the blown air or steam is smaller in the outlet hole 14a. 14b smaller than the head difference 15
Is higher in the blowout hole 14a than in the blowout hole 14b, so that the blowout flow rates are equal or almost equal. As a result, each blowout hole 14 in the arm 10 of the quencher 13
Since a and b can blow out an equal amount of air and steam from a and b, the blowing efficiency is improved.

A large number of unillustrated blowout holes provided between the blowout holes 14a and 14b also correspond to the difference in the separation distance from the base of the arm 10 and correspond to the blowout holes 14a and 14b. Is the same as in
Can be almost equal.

The sixth embodiment relates to claim 6 and relates to a quencher. As shown in the front view of FIG. 6, a plurality of arms 10 provided on a quencher 16 are provided with a plurality of blowouts having different hole diameters in the axial direction. The holes 17a and 17b are formed. The blowout holes 17a, 17b formed in the arm 10
Is a blowout hole 17 at a position of a distance l close to the base of the arm 10.
The distance L farther from the base of the arm 10 than the hole diameter d of a
The hole diameter D of the blowout hole 17b at the position (d <
D).

The diameters d and D of the blowout holes 17a and 17b are
Assuming that the hole diameters are the same, the pressure loss when air and steam are blown out from the blowout hole 17a at a distance l from the base of the arm 10 of the quencher 16 and the blowout hole 17 at a distance L
It is selected so that the difference from the pressure loss when air and steam blows out from b is equal to or substantially equal to the difference in pressure loss when the hole diameter d (small diameter) is changed to the hole diameter D (large diameter).

As a result, the flow rate of the blow-out from the blow-out hole 17a, which is provided at a position of a distance 1 close to the base of the arm 10,
The blowout flow rate from the blowout hole 17b provided at the position of the far distance L is configured to be equal or almost equal. Note that the arm (not shown) provided between the outlet 17a and the outlet 17b also includes the arm.
By gradually increasing the hole diameter in accordance with the separation distance from the base of 10, the blowout flow rate is equal to or substantially equal to the blowout holes 14a and 14b.

Next, the operation of the above configuration will be described. The air and steam flowing down the exhaust pipes 4a, 4b, and 12 and flowing into the arm 10 of the quencher 16 from the outlet holes 17a and 17b into the suppression pool water 9 are discharged from the arm 10
A pressure loss occurs according to the moving distance in the inside. For this reason, when the diameters of the blowout holes 17a and 17b are the same, a difference occurs in the blowout flow rate due to the pressure loss between the blowout hole 17a at a distance 1 close to the base of the arm 10 and the blowout hole 17b at a long distance L. The blow hole 17a is larger than the blow hole 17b.

However, in the quencher 16,
Since the diameter d of the blowout hole 17a near the base of the arm 10 is smaller than the diameter D of the blowout hole 17b located at the tip of the arm 10, the hole diameters d and D of the blowout holes 17a and 17b are set.
, The pressure loss at the time of blowing is larger in the blowing hole 17a than in the blowing hole 17b. As a result, the blowout flow rate of the blowout hole 17a having a small hole diameter d near the base of the arm 10 and the blowout hole 17b having a large blowout hole 17D farther from the base of the arm 10 becomes uniform, and the blowout efficiency is improved.

[0072]

As described above, according to the present invention, by branching the exhaust pipe from the MSSRV into a plurality of parts and connecting a quencher to each of them, fluctuations in the generated pressure as well as the amount of air and steam blown out per quencher are reduced. Maintain the soundness of the containment vessel.

In addition, by combining a plurality of exhaust pipes from a plurality of MSSRVs into a common exhaust pipe and reducing the number of exhaust pipes, the arrangement and workability of the exhaust pipes are improved, and at the same time, the blow set pressure can be reduced. By combining the exhausts of different MSSRVs into one exhaust pipe, the blowing speed when the air in the exhaust pipe is blown into the suppression pool water decreases, and the soundness of the reactor containment vessel is maintained well.

Further, by increasing the angle of the arm of the quencher or gradually increasing the diameter of the blowout hole toward the tip of the arm, the amount of air and the amount of steam blown out from each blowout hole are equalized, and the blowing efficiency is improved. improves.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of an MSSRV exhaust device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of an MSSRV exhaust device according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a main part of an exhaust device of an MSSRV according to a third embodiment of the present invention.

FIG. 4 is an explanatory diagram of an arrangement of MSSRVs in a fourth embodiment according to the present invention.

FIG. 5 is a front configuration diagram of a quencher according to a fifth embodiment of the present invention.

FIG. 6 is a front configuration diagram of a quencher according to a sixth embodiment of the present invention.

FIG. 7 is a cross-sectional view of a main part of a conventional MSSRV exhaust device.

[Explanation of symbols]

1 ... Reactor pressure vessel, 2 ... Main steam pipe, 3a-3d, 3a
_{1 ~3d 1, 3a 2 ~3d 2} , 3a 3 ~3d 3, 3a 4
3d ₄ … MSSRV, 4a, 4b… exhaust pipe, 5… reactor containment vessel, 6… diaphragm floor, 7… suppression chamber, 8, 13, 16… quencher, 9… suppression pool water, 10… arm, 11a , 11b ... branch exhaust pipe, 12 ... combined exhaust pipe, 14a, 14b ... outlet hole, 15 ... head difference, 17a ... outlet hole (small diameter), 17b ... outlet hole (large diameter), D ... hole diameter (large diameter), d: hole diameter (small diameter), L: distance from the base of the arm (far), l: distance from the base of the arm (close), θ: elevation angle of the arm.

Claims (6)

[Claims] 1. A plurality of main steam relief valves, which are automatically opened at a preset blow-out pressure when an excessive pressure rise of a nuclear reactor is connected to a plurality of main steam pipes,
An exhaust pipe connected to each of the main steam release safety valves and guiding discharged steam to the suppression chamber is branched into a plurality of sections in the suppression chamber, and a quencher for blowing air and steam is connected to each of the exhaust pipes. Exhaust device for steam release safety valve. 2. A plurality of main steam release safety valves, which are automatically opened at a preset blow set pressure upon an excessive rise in pressure of a reactor, are connected to a plurality of main steam pipes, respectively.
An exhaust pipe connected to the plurality of main steam relief safety valves and guiding the discharged steam to the suppression chamber is connected to a common combined exhaust pipe at the top of the suppression chamber, and air and air in the suppression chamber at the tip of the combined exhaust pipe. An exhaust device for a main steam relief safety valve, wherein a quencher for blowing steam is connected. 3. A plurality of main steam relief valves, which are automatically opened at a preset blow set pressure upon an excessive rise in pressure of the reactor, are connected to the plurality of main steam pipes.
An exhaust pipe connected to the plurality of main steam relief safety valves to guide discharged steam to the suppression chamber is connected to a common combined exhaust pipe at the upper part of the suppression chamber, and the tip of the combined exhaust pipe is connected to a plurality of parts in the suppression chamber. An exhaust device for a main steam release safety valve, characterized in that a quencher that branches off and blows air and steam is connected to each branch. 4. A plurality of main steam relief valves, which are automatically opened at a preset blow set pressure upon an excessive rise in pressure of the reactor, are connected to the plurality of main steam pipes,
The exhaust device for a main steam relief safety valve according to claim 2 or 3, wherein a plurality of main steam relief safety valves having mutually different blowing set pressures are connected to a common combined exhaust pipe. 5. An exhaust pipe connected to the main steam release safety valve and connected to a combined exhaust pipe that guides discharge steam to a suppression chamber, and a quencher that protrudes to the periphery and has a large number of blowout holes formed in an axial direction. 5. An exhaust device for a main steam relief safety valve according to claim 1, wherein an elevation angle is provided such that a blowout flow rate in each of said blowout holes is equal or substantially equal. 6. An exhaust pipe connected to the main steam release safety valve and connected to a combined exhaust pipe for guiding discharged steam to a suppression chamber and a quencher connected to a combined exhaust pipe, wherein each of the arms has a plurality of axially-discharged holes projecting therefrom. The main steam release according to claim 1, wherein a diameter of the blowout hole is gradually increased from a base of the arm toward a tip portion so that a blowout flow rate in each of the blowout holes becomes equal or almost equal. 5. Exhaust device for safety valve.