JPS5948691A - Main steam leakage control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The invention relates to a main steam leak suppression device in a boiling water nuclear reactor plant.

[Technical background of the invention]

In the event of a loss of coolant accident (hereinafter referred to as LOCA) or a rupture of the main steam piping outside the containment vessel (hereinafter referred to as MSLB), containment occurs in response to the generation of the reactor LOCA signal or MSLB signal inserted in the main steam piping. The inner main steam isolation valve on the inside of the vessel and the outer main steam isolation valve on the outside are automatically closed in an emergency, but if a seat leak occurs in these main steam isolation valves, the main steam will be leaked to the outside of the reactor building. There is a risk of leakage. Therefore, a main steam leak suppression device is provided to prevent this. That is, the main steam leakage suppression device is intended to reduce the amount of steam leaking to the outside of the reactor building during LOCA, MST, or B, and includes a bleed system and a vent system.

The bleed system releases main steam leaking from the main steam isolation valve into the space between the reactor containment vessel and the reactor building during a LOCA. The main steam released into the reactor building will be treated in the emergency gas treatment system and then released into the atmosphere.

By guiding leaked steam from the main steam isolation valve to the pressure suppression pool and condensing it during vent system MSLB, the total amount of leaked main steam flowing out to the turbine equipment is reduced.

That is, as shown in FIG. 1, a reactor containment vessel 2 is installed in a nuclear reactor building 1, and a reactor pressure vessel 4 is housed within this containment vessel 2. As shown in FIG. and reactor pressure vessel 4
The high-temperature, high-pressure main steam generated inside the
The steam is supplied to the turbine equipment 8 provided outside the reactor building 1 via the main steam pipe 6 of the reactor building 1. Note that the main steam pipe 6 is provided to pass straight through the side walls of the containment vessel 2 and the reactor building 1.

In each main steam piping 6, an inner main steam isolation valve 10 is inserted inside the containment vessel 2, and a first main steam isolation valve 10 is inserted on the outside of the containment vessel 2. Second
Outer main steam isolation valve 12A.

12B is inserted (the first outer main steam isolation valve 12 is on the upstream side). In addition, these live steam isolation valves 10.1
2. Both valves 12B are kept open during normal operation.

In addition, the main steam pipe 6 has a first. Second outer main steam isolation valve 1
2, vent system branch piping i on each upstream side of 12B
4 A l i 4 B is connected, and each vent system branch pipe 141.14B has a vent system branch valve 16 and a 16
B is inserted.

Note that the vent system branch valve 161.16B is kept closed during normal operation. And each vent system branch pipe 1
4, 18B is connected to the bleed system branch pipe 18 on the upstream side of the vent system branch valve 161.16B,
In each bleed system piping 18A, 18B, there is a bleed system branch valve 20A, ;! An OR is inserted. In addition, 20B of these bleed system branch valves 20 is also maintained in a closed state during normal operation.

The above is the same for the four main steam pipes 6, and the four vent system branch pipes J4AC14B) are connected to one vent system common pipe 22k (22B), and the four bleed system branch pipes 18A (Same as 18B) is connected to one bleed system common pipe 24k (24B).

The vent system common pipe 22k (22B) extends into the pressure suppression pool 26 provided at the lower part of the containment vessel 2, and the bleed system common pipe 24A (24B) connects the reactor containment vessel 2 and the atomic One end is opened into the space between it and the furnace building 1.

A vent system common valve 28A (28B) is inserted into the vent system common pipe 22A (22B), and a bleed system upstream common valve 30A (30B) is inserted into the bleed system common pipe 24A (?4B). Bleed system downstream common valve 32A (
32B) is inserted. And these common valve 2
8A,', 2ξB, 30, and 30B are also kept closed during normal operation.

The bleed system common pipe 24A (24B is the same) has an upstream common valve 5oh (soB) and a downstream common valve 32A (32B).
) is connected to the drain pipe J4A (, 94B), and a drain valve 361L (, 96B) is inserted into the drain pipe J4A (, 94B). These drain valves 36 A, ? 6B is kept closed during normal operation;

20, when any one of the valves 20B is fully opened, the valves are closed in conjunction with this. And both drain pipes 3'4A, 34B
The bleed system common pipe 24A extends into the pressure suppression nozzle 36 as a single pipe.

The water component in 24B is configured to be able to flow down to the pressure suppression pool 26 at all times.

In the main steam leakage suppression device configured as described above, L
When the OCA signal is generated, the inner main steam isolation valve 10 and the first outer main steam isolation valve 12k are all automatically closed as shown in FIG. Then, the operator manually closes the second outer main steam isolation valves 12B in all the main steam pipes 6 as shown in FIG. First, the bleed system branch valve 20B and the bleed system common valve 30B in the bleed system branch pipe 14B connected to the main steam pipe 6 of the first wood.

32B is opened. As a result, the main steam accumulated between the first outer main steam isolation valve 12 in the first main steam pipe 6 and the second outer main steam isolation valve 12B is transferred to the bleed system common pipe. Reactor building 1 through 4B
released within. At this time, the first outer main steam isolation valve 12
If there is a seat leak in the main steam isolation valve 12k, the amount of released steam will increase, so by detecting the released steam -it', it can be easily determined whether a seat leak has occurred in the main steam isolation valve 12k. . After the first bleed system branch valve 20Bf is closed, the bleed system branch valve 20B is similarly applied to the second and subsequent main steam pipes 6 as shown in FIG.
After opening and closing the fourth main steam pipe 6, open and close the bleed system common valves 30B and 32Bf.
Close the valve.

Next, regarding the first main steam pipe 6, as shown in FIG. 6, the bleed system branch valve 20A and the bleed system common valve sob, 32B in the bleed system branch pipe 14 on the reactor pressure vessel 4 side are opened. As a result, the main steam accumulated between the inner main steam isolation valve 10 and the first outer main steam isolation valve 12 is discharged into the reactor building 1 through the bleed system common pipe 24k. At this time, the inner main steam isolation valve 10 is closed)
If a leak occurs, the amount of released steam will increase, so by detecting the amount of released steam, it can be easily determined whether or not a leak is occurring in the main steam isolation valve 10. . And the first bleed system branch valve 20k
f After closing the valve, the second and subsequent main steam pipes 6 as shown in Figure 7.
Similarly, the bleed system branch valve 20 is opened and closed, and after the operation for the fourth main steam pipe 6 is completed, the bleed system common valves 30A and 32A are closed. The main steam released into the reactor building 1 is treated in an emergency gas treatment system (not shown) and then released into the atmosphere.

Also, when the MSLB signal is generated, the inner main steam isolation valve 10 and the first outer king steam isolation valve 12k are all automatically closed in this case as well (see FIG. 2).

Then, the operator manually closes the second outer main steam isolation valves 12Bf in all the main steam pipes 6 (see Fig. 3), and then closes them first among the four main steam pipes 6 as shown in Fig. 8. Vent system branch valve 1 connected to the first main steam pipe 6
6B and the vent system common valve 28B are opened. As a result, the first outer main steam isolation valve 1 in the first main steam pipe 6
2 and the second outer main steam isolation valve 12B is discharged into the pressure suppression pool 26 through the vent system common piping 22B, and is condensed and liquefied by pool water. At this time, if a seat leak occurs in the first outer main steam isolation valve 12k, the steam flow rate in the vent system common piping 22B will increase, so by detecting this flow rate, it can be determined that a seat leak has occurred in the main steam isolation valve 12A. It can be easily determined whether there is a

After closing the first vent system branch valve 16Bf, the 9th
As shown in the figure, open and close the vent system branch valve 16B for the second and subsequent main steam pipes 6 in the same way, and after completing the operation for the fourth main steam pipe 6, close the vent system common valve 28k. .

Next, for the first main steam pipe 6, the vent system branch valve 16 in the vent system branch pipe 22A on the reactor pressure vessel 4 side and the vent system common valve 28 are opened as shown in FIG. 10. As a result, the main steam accumulated between the inner main steam isolation valve 10 and the first outer main steam isolation valve 12 is discharged into the pressure suppression pool 26 through the vent system common piping 22A, and is condensed and liquefied by the pool water. . In this case as well, it is possible to easily determine whether a seat leak has occurred in the inner main steam isolation valve 10 based on the flow rate in the vent system common pipe 22A. And the first vent system branch valve 16
After the Af valve is closed, the vent system branch valves 16 are opened and closed in the same manner for the second and subsequent main steam pipes 6 as shown in FIG. 11, and after completing the operation for the fourth main steam pipe 6, Vent system common valve 28Af is closed.

[Problems with background technology]

A conventional main steam leakage control device is a through-flow system branch pipe 14A shown in FIGS. 1 to 11.

24B and bleed system branch pipe 18, 18B-10-
.

The number of these is extremely large because they are provided separately. Therefore, the configuration is complicated, and the operation when generating the LOCA signal or MSLB signal is also complicated.

[Purpose of the invention]

The present invention was made based on these circumstances, and
The purpose of this is to create a configuration that allows most of the piping and valves used when generating the LOCA signal to be used as the piping and valves used when generating the MSLB signal, thereby reducing the number of piping and valves, and making the configuration simple and easy to operate. An object of the present invention is to provide a Hikoshu steam leakage control device.

[Summary of the invention]

A main steam leakage prevention device according to the present invention includes a plurality of leakage branch pipes connected to the upstream side of each outer main steam isolation valve of a plurality of main steam pipes between a reactor containment vessel and a reactor building;
A branch valve inserted in each leakage branch pipe, a common pipe commonly connected to the plurality of branch pipes, and a vent connected to this common pipe to guide steam in the main steam pipe to the pressure suppression pool. system piping, a vent system common valve inserted in the vent system piping, and a vent system common valve connected to the common piping to release main steam in the main steam piping into the space between the reactor containment vessel and the reactor building. The special feature is that the system is equipped with a bleed system piping and a bleed system common valve inserted into the bleed system piping.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 12191 to 22.

A reactor containment vessel 102 is installed in the reactor building 101, and a reactor pressure vessel Z04 is installed inside this containment vessel 102.
is stored. The high-temperature main steam generated inside the reactor pressure vessel 104 is supplied to the turbine equipment 10& provided outside the reactor building 1 via a plurality of (for example, four) main steam pipes 106. Note that the main steam pipe 6 is provided to completely penetrate the side walls of the containment vessel 102 and the reactor building 101.

In each main steam piping 10, 6, a main steam isolation valve 11θ is inserted inside the containment vessel 102, and a main steam isolation valve 11θ is inserted outside the containment vessel 102. Second outer main steam isolation valves 112A and 112B are interposed (the first outer main steam isolation valve 112A is on the upstream side). In addition, these main steam isolation valves 110, 112k
.

112B are both kept open during normal operation. In addition, the main steam pipe 106 has a first. Leakage branch piping I J 4A is provided upstream of each of the second outer main steam isolation valves I J ffA and 112B.

114B is connected. And leakage branch pipe 114
1' (same as 114B), there is a branch valve 116k (11
6B) is inserted. Note that these branch valves 116
In addition, valve 116B is kept closed during normal operation. The above is the same for the four main steam pipes 106.9.
Four leakage branch pipes J24A (JJ4B) are connected to one common pipe 118A (ZJ sB) (A in the figure).
The common piping 118 between o and A1 and between Bo and B1 is 118B). And this common pipe 118A (1
A vent system pipe 119A (119B) is connected to one end (AI 7B+ ) 13- of the pipe 18B). This vent system pipe 719k (119B) extends into the pressure suppression sol 120 provided at the lower part of the containment vessel 102, and the vent system pipes 119A, 1
A vent system common valve 122k (122B) is inserted in 19B. These vent system common valves 122A,
122B is also kept closed during normal operation.

Also, one end (Alp) of the common pipe 118k (118B)
Bt) has bleed system piping 124AC1,? 4B
) are connected. This bleed system piping 124k (1
24B) has one end open in the space between the reactor containment vessel 102 and the reactor building 101, and a bleed system upstream common valve 1 is installed in each bleed system pipe 124A (124B).
26A (126B) and bleed system downstream common valve 128A (
228B) is inserted. And these common valves 126, 126B, 1281L.

128B is also kept closed during normal operation. 14- The bleed system piping 124A (same as 124B) has an upstream common valve 126k (126B) and a downstream common valve 128k (
128B) between the drain pipe 13θA (J,?
OB) is connected, and this drain pipe 130A (130
A drain valve 132k (132B) is inserted in B). These drain valves 1.921', , 1.92B are kept closed during normal operation, but when any one of the branch valves 116B is opened, they are closed accordingly. speak. Then, in both drain pipes 130, 1
30B extends into the pressure suppression pool 120 as a single line, and is configured so that the water component in the bleed system piping 124k (124B) can flow down into the pressure suppression pool 120 at all times.

Next, the operation of the main steam leakage suppression device configured as above will be explained.

While the reactor is operating in the state shown in Figure 12, if an abnormal situation occurs and the LOCA signal is generated,
As shown in FIG. 13, the inner main steam isolation valve 110 and the first outer main steam isolation valve 112 are all automatically closed. Then, the operator manually closes the second outer main steam valves 112B in all the main steam pipes 106 as shown in FIG.
Next, as shown in FIG. 15, among the four main steam pipes 106,
First, the branch valve 116B in the leakage branch pipe 114B connected to the first main steam pipe 106 and the bleed system pipe 124
Fully open the bleed system common valves 126B and 128B in B.

As a result, the first outer main steam isolation valve 112 in the first main steam pipe 106 and the second outer main steam isolation valve 112B
The main steam accumulated between the two is discharged into the reactor building 101 through the bleed system piping 124B. At this time, if a seat leak occurs in the 112 people of the first outer main steam isolation valve, the amount of released steam will increase, so by detecting the released steam tv, it can be determined whether a seat leak has occurred in the 112 people of the main steam isolation valve. All can be easily determined. After closing the first branch valve 116Bf, as shown in FIG.
After completing the operation for 6, open the bleed system common valve 12.
6B, 128B'z valves are closed.

Next, regarding the first main steam pipe 106, as shown in FIG. 17, a branch valve 116A in the leakage branch pipe 114A on the reactor pressure vessel 1/04 side and a bleed system common valve 126k in the bleed system pipe 124A.

Open the 128Af valve. As a result, the main steam accumulated in the inner main steam isolation valve 110 and the first outer main steam isolation valve 112A is routed through the entire bleed system piping 124A to the nuclear route building 1.
Release within 01. At this time, the inner main steam isolation valve 110
If a seat leak occurs in the main steam isolation valve 110, the amount of released steam will increase, so by detecting the amount of released steam, it can be easily determined whether a seat leak is occurring in the main steam isolation valve 110. And the first branch valve J J 6A
'i After the valve is closed, the branch valve 116A is opened and closed in the same way for the second and subsequent main steam pipes 106 as shown in Fig. 18, and after completing the operation for the main steam pipe 106 at the fourth grain 17-, Close the bleed system common valves 126k and 128k. In addition,
The main steam released into the reactor building 101 is treated in an emergency gas treatment system (not shown) and then released into the atmosphere.

Also, when the MSLB signal is generated, the inner main steam isolation valve 110 and the first outer main steam isolation valve 112A are all automatically closed in this case as well (see FIG. 13). The operator then installs the second outer main steam isolation valve 1 in all main steam lines 106.
12B (closed by manual operation (see Fig. 14)), and then the branch valve 116 connected to the first main steam pipe 106 out of the four main steam pipes 106 as shown in Fig. 19.
B and the vent system common valve 122B are opened. As a result, the main steam accumulated between the first outer main steam isolation valve 112A and the second outer main steam isolation valve 112B in the first main steam pipe 106 flows into the pressure suppression sol 120 through the vent system arrangement 119T3f. released and condensed into liquid by pool water. At this time, if there is a leak in the first outer main steamer 18-air isolation valve 112,
Since the steam flow rate in the vent system piping 119B increases, by detecting this flow rate, it can be easily determined whether a seat leak has occurred in the main steam isolation valve 112A. After closing the first branch valve 116B,
As shown in FIG. 20, the branch valve 116B is opened and closed in the same manner for the second and subsequent main steam pipes 106, and after the operation for the fourth main steam pipe 106 is completed, the vent system common valve 122B is closed. .

Next, regarding the first main steam pipe 106, as shown in Fig. 21, the branch valve 116A in the leakage branch pipe 114 on the reactor pressure vessel 104 side and the vent system common valve 122A in the vent system pipe 119 are opened. . As a result, the main steam accumulated between the inner main steam isolation valve 110 and the first outer main steam isolation valve 112 is removed from the vent system pipe JJ! 9Ai into the pressure suppression pool 120, and is condensed and liquefied by the pool water. In this case as well, if there is a seat leak in the inner main steam isolation 110, it can be easily determined based on the flow rate in the vent system piping 119A. After closing the first branch valve 116Af, the opening/closing operations of the branch valves 116A were similarly performed for the second and subsequent main steam pipes 1θ6 as shown in Fig. 22, and the operation for the fourth main steam pipe 106 was completed. Afterwards, the vent system common valve 122Af is closed.

Although one embodiment has been described above, the present invention is also applicable to a case where each main steam pipe has one outer main steam isolation valve.

〔Effect of the invention〕

As detailed above, the main steam leakage suppression device of the present invention includes:
Since the leakage branch pipe, the common pipe, and the branch valve are commonly used both when the LOCA signal is generated and when the MSLB signal is generated, the number of pipes and valves can be significantly reduced.

Further, by reducing the number of valves, valve operation becomes less complicated and easier, and other excellent effects can be obtained.

[Brief explanation of drawings]

Figures 1 to 11 are piping system diagrams showing conventional examples;
2 to 22 are piping system diagrams showing one embodiment of the present invention. 101... Reactor building, 102... Reactor containment vessel, 104... Reactor pressure vessel, 106... Main steam piping, 110... Inner main steam isolation valve, 1121'. 112B...Outside main steam isolation valve, 114A, J f
4B... Leak branch pipe, 116... Branch valve, 118
1゜118B... common piping, 119, 119B...
・Vent system common valve, 124, 124B... Bleed system piping, 126A, 126B, 128, 128B
...Bleed system common valve. Applicant's agent Patent attorney Takehiko Suzue 21-

Claims (1)

[Claims] A plurality of leakage branch pipes connected to the upstream side of each outer main steam isolation valve of a plurality of main steam pipes between the reactor containment vessel and the reactor building, and a branch valve inserted in each leakage branch pipe. , a common pipe commonly connected to the plurality of branch pipes, a vent system pipe connected to the common pipe to guide steam in the main steam pipe to the pressure suppression pool, and a vent system pipe inserted in the vent system pipe. a vent system common valve, a bleed system pipe that is connected to the common pipe and discharges main steam in the main steam pipe into the space between the reactor containment vessel and the reactor building; A main steam leakage suppression device characterized by comprising a bleed system common valve inserted therein.