JP2003315482A - Ventilation facility at top part of reactor pressure vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide ventilation facilities at the top part of a reactor pressure vessel capable of efficiently and reliably preventing non-condensable gases from being accumulated in the vicinity of the top part of the reactor pressure vessel and performing highly reliable and stable operation. <P>SOLUTION: The ventilation facilities 20 at the top part of the reactor pressure vessel (RPV) is provided with both an RPV head spray system 31 for supplying cooling water for an RPV head spray nozzle 36 at the upper part of the RPV 22 and a RPV ventilation system 30 for guiding non-condensable gases which occurs during operation of a reactor to a main steam pipe 37. The RPV head spray system 31 is provided with a branched ventilation system 32 branched from a check valve 39, provided on RPV head spray piping 38, on the side of the RPV 22. The branched ventilation system 32 is constituted in such a way as to guide the non-condensable gases which occur in the RPV 22 to the side of the main steam pipe 27 with the RPV ventilation system 30 during normal operation of the reactor. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear reactor pressure vessel top vent facility for treating non-condensable gases present in the reactor pressure vessel.

[0002]

2. Description of the Related Art Generally, in a boiling water nuclear power plant (hereinafter referred to as BWR plant), a gas treatment facility around the top of a reactor pressure vessel (hereinafter referred to as RPV) 2 is constructed as shown in FIG. To be done. The BWR plant has an RPV in the reactor containment vessel (hereinafter referred to as PCV) 1.
The (reactor pressure vessel) 2 is stored. A reactor core 3 is housed in the RPV 2, and the reactor core 3 is immersed in reactor cooling water 4. The inside of the RPV 2 is divided into a liquid phase part in which the reactor cooling water 4 is stored and a gas phase part 5 above the liquid phase part.

In the reactor cooling water 4 in the RPV 2, hydrogen gas and oxygen gas, which are decomposed and produced from the cooling water 4 by neutron irradiation accompanying the nuclear reaction in the core 3, or, in some cases, a trace amount from the fuel rods are produced. There are leaking non-condensable gases such as radioactive noble gases such as Kr and Xe. For this reason, the gas waste treatment system (not shown) for treating the non-condensable gas is BW.
It is installed in the R plant.

During normal operation of the BWR plant, the non-condensable gas generated in the RPV 2 is guided from the RPV 2 via the main steam pipe 6 connected to the steam turbine T, and is guided to the condenser via the steam turbine T. After that, it is treated in the gaseous waste treatment system provided in this condenser. The main steam pipe 6 has P
Main steam isolation valves 7a and 7b are provided on the upstream side and the downstream side of the CV (reactor containment vessel) 1, respectively.

A reactor pressure vessel vent pipe (hereinafter referred to as RPV vent pipe) 8 is provided on the top of the RPV 2. The RPV vent pipe 8 is connected to the main steam pipe 6 via the motor-operated valve 9 on the upstream side of the main steam isolation valve 7a, and constitutes a reactor pressure vessel vent system (hereinafter, RPV vent system) 10. The RPV vent system 10 discharges the non-condensable gas that may accumulate in the RPV 2 from the top of the RPV 2 and joins the main steam passing through the main steam pipe 6.

Furthermore, the BWR plant is shut down and the RP
When cooling V2, a reactor pressure vessel head spray system (hereinafter, RPV) that supplies cooling water to the upper part of RPV2 in order to cool the vapor phase portion 5 in RPV2 that is in the vapor phase
It is called a head spray system. ) 11 is provided. This R
The RPV head spray pipe 12 of the PV head spray system 11 is provided with a check valve 13 and reactor containment (PCV) isolation valves 14a and 14b near the inside and outside of the PCV 1, respectively.

When the boiling water reactor is stopped, cooling water is supplied from the RPV head spray pipe 12 through the check valve 13 to the RPV.
2 is sprinkled with water to cool the upper part of RPV2.

[0008]

The non-condensable gas generated in the RPV 2 during the normal operation of the boiling water reactor is basically a gas discharged from the condenser through the main steam pipe 6 and the steam turbine T. It is transferred to the waste treatment system and treated in this gaseous waste treatment system. The non-condensable gas accumulated in the upper part of the RPV 2 is also discharged into the main steam pipe 6 by the RPV vent system 10,
The design is designed to prevent the accumulation of non-condensable gas above the RPV2.

However, the RP connected to the top of the RPV2
The V head spray system 11 does not take measures to prevent the accumulation of non-condensable gas. In order to reliably prevent the accumulation of non-condensable gas even around the top of RPV2, it is necessary to prevent the accumulation itself of the part where there is a possibility of non-condensable gas accumulation, in order to stabilize the nuclear power plant. It is important for ensuring reliable operation and reliable operation.

On the other hand, during normal operation of the boiling water reactor, R
It is known that hydrogen gas and oxygen gas, which are the main components of the non-condensable gas generated in PV2, are accumulated at the rising portion of the pipe. From this point of view as well, it is strongly desired to prevent gas accumulation in the top of the RPV2 where there is a possibility that some non-condensable gas may accumulate, in advance.

The present invention has been made in consideration of the above-mentioned circumstances, and efficiently and reliably prevents the accumulation of non-condensable gas around the top of the reactor pressure vessel, and ensures reliable and stable operation. It is an object of the present invention to provide a reactor pressure vessel top venting device capable of performing the above.

Another object of the present invention is to prevent the non-condensable gas from accumulating around the top of the reactor pressure vessel during normal operation, and to surely prevent the non-condensable gas from being accumulated during operation of the reactor isolation cooling system. It is to provide a venting equipment at the top of a reactor pressure vessel that can sufficiently maintain its function.

Another object of the present invention is to efficiently remove the non-condensable gas from the non-condensable gas accumulation portion where it is difficult to exhaust the non-condensable gas from around the reactor pressure vessel in the conventional reactor pressure vessel vent system. It is an object of the present invention to provide a vent facility at the top of a reactor pressure vessel that effectively and effectively exhausts gas and prevents the accumulation of non-condensable gas.

[0014]

In order to solve the above-mentioned problems, the reactor pressure vessel top venting equipment according to the present invention is, as set forth in claim 1, a reactor pressure vessel above a reactor pressure vessel. In a reactor pressure vessel having a reactor pressure vessel head spray system for supplying cooling water to a head spray nozzle and a reactor pressure vessel vent system for guiding a non-condensable gas generated during a reactor operation to a main steam pipe, The reactor pressure vessel head spray system comprises a branch vent system branched from the reactor pressure vessel side of the check valve provided on the reactor pressure vessel head spray pipe, and the branch vent system is the reactor. It is configured to guide the non-condensable gas generated in the reactor pressure vessel to the main steam pipe side together with the pressure vessel vent system.

In order to solve the above-mentioned problems, the venting equipment at the top of the reactor pressure vessel according to the present invention comprises:
As described above, the branch vent system includes a vent branch pipe branched from the reactor pressure vessel head spray pipe of the reactor pressure vessel head spray system, and the vent branch pipe is an on-off valve that is remotely operated on the way. It is connected to the main steam pipe side via the, further, as described in claim 3, the branch vent system is branched from the reactor pressure vessel head spray pipe of the reactor pressure vessel head spray system. This vent branch pipe is connected to the reactor pressure vessel vent pipe of the reactor pressure vessel vent system at the upstream side of the on-off valve provided in this reactor pressure vessel vent pipe. .

Further, in order to solve the above-mentioned problems,
In the reactor pressure vessel top vent equipment according to the present invention, as described in claim 4, the branch vent system is a vent branch pipe branched from the reactor pressure vessel head spray pipe of the reactor pressure vessel head spray system. This vent branch pipe is connected to the reactor pressure vessel vent pipe of the reactor pressure vessel vent system on the downstream side, while a remotely operated on-off valve is provided in the middle of the vent branch pipe.
Further, as described in claim 5, the branch vent system comprises a vent branch pipe branched from a reactor pressure vessel head spray pipe of a reactor pressure vessel head spray system, and the downstream side of the branch pipe is the reactor. While being connected to a reactor pressure vessel vent pipe of a pressure vessel vent system, an on-off valve and an orifice which are remotely operated are provided in the middle of the vent branch pipe.

In order to solve the above problems, the reactor pressure vessel top vent equipment according to the present invention is provided in claim 6.
As described above, in the reactor pressure vessel head spray system, reactor containment vessel isolation valves are provided inside and outside the reactor containment vessel of the reactor pressure vessel head spray piping, while the reactor pressure vessel head is provided. The spray pipe is configured so as to also serve as the injection pipe of the reactor isolation cooling facility. Further, as described in claim 7, the opening / closing valve provided in the vent branch pipe of the branch vent system is:
The reactor pressure vessel head spray system is configured to be closed by an opening permission signal of the reactor containment vessel isolation valve.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a reactor pressure vessel top vent facility according to the present invention will be described with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a schematic system diagram showing a first embodiment of a reactor pressure vessel top vent equipment according to the present invention.

This reactor pressure vessel top vent equipment is generally designated by the numeral 20, and a reactor containment vessel (hereinafter referred to as PCV) 2 of a boiling water nuclear power plant (BWR plant) 2
1 and a reactor pressure vessel (hereinafter referred to as RPV) 22 are installed in a dry well 37.

The BWR plant is a reactor containment vessel (PC
A reactor pressure vessel (RPV) 22 is housed in V) 21 and a reactor core 23 is housed in this RPV 22. The reactor core 23 is immersed in the reactor cooling water 24. A liquid phase portion storing the reactor cooling water 24 is formed in the lower portion of the RPV 22, while a vapor phase portion 25 of the RPV 22 is formed above the liquid phase portion.

The reactor cooling water 24 in the RPV 22 is heated and vaporized by being irradiated with neutrons due to a nuclear reaction while passing through the core 23. The generated steam is separated into water and water in the RPV 22, dried, and then sent to the steam turbine 28 through the main steam pipe 27 to work in the steam turbine 28.
Drive a generator (not shown). The main steam pipe 27 is provided with main steam isolation valves 29 a and 29 b on the upstream side and the downstream side of the reactor containment vessel 21, respectively. The steam that has worked in the steam turbine 28 and has expanded is condensed in a condenser (not shown) and then passes through the reactor condensate / water supply system to R
It is returned to the PV 22 again.

Further, the reactor pressure vessel top vent facility 20 provided in the reactor pressure vessel (RPV) 22 of the BWR plant is a reactor pressure vessel (RPV) vent system 30.
And a branch vent system 32 branched from a reactor pressure vessel head spray system (hereinafter referred to as an RPV head spray system) 31.

The RPV vent system 30 is a reactor pressure vessel (RPV) vent pipe 33 connected to the top of the RPV 22.
Have. The RPV vent pipe 33 is connected to an RPV head vent nozzle 34 formed on the top of the RPV 22, and on the other hand, an electric valve 3 which is remotely operated as an on-off valve.
5 are provided. The downstream side of the motor-operated valve 35 is connected to the main steam pipe 27 on the upstream side of the main steam isolation valve 29 a in the reactor containment vessel 21.

The branch vent system 32 also includes a vent branch pipe 40 branched from the check valve 39 downstream side of the reactor pressure vessel (RPV) head spray pipe 38. The vent branch pipe 40 is also provided with an electrically operated valve 41 which is remotely operated as an on-off valve in the middle thereof, and the downstream side of the electrically operated valve 41 is the main steam pipe 27.
To the upstream side of the main steam isolation valve 29a.

Further, the RPV head spray system 31 is
The RPV head spray pipe 38 is provided on the top of the RPV 22 and the reactor pressure vessel head spray nozzle (hereinafter,
It is called RPV head spray nozzle. ) 36. The RPV head spray pipe 38 of the RPV head spray system 31 may also serve as the cooling water injection pipe of the reactor isolation cooling facility (hereinafter referred to as RCIC) 43. The RCIC 43 is a facility for cooling the gas phase part 25 of the RPV 22 by using the cooling water of the cooling system during shutdown in order to reduce the residual pressure of the RPV upper dome when the boiling water reactor is shut down.

On the other hand, the RPV head spray pipe 38 is provided with a check valve 39 and reactor containment isolation valves (PCV isolation valves) 44a and 44b on the way. The PCV isolation valves 44a and 44b are installed inside and outside the reactor containment vessel 21, respectively, and are normally closed during the operation of the reactor.

By the way, the reactor pressure vessel top vent equipment 20 comprises an RPV vent system 30 and a branch vent system 32 utilizing an RPV head spray system 31. Both vent systems 30 and 31 work in concert to operate the reactor pressure vessel 22.
The non-condensable gas is led out from the area where the non-condensable gas can be accumulated, and is discharged to the main steam pipe 27. At the top of the reactor pressure vessel (RPV) 22, the RPV vent system 3
0 and a branch vent system 32 using the RPV head spray system 31 are provided to cooperate with each other, so that oxygen gas in a portion that may accumulate near the top of the RPV 22 during normal operation of the nuclear power plant. , Hydrogen gas and Kr, X
The non-condensable gas such as the radioactive noble gas of e can be smoothly and smoothly discharged to the main steam pipe 27 side, and the accumulation of the non-condensable gas around the top of the RPV 22 can be prevented in advance.

Next, the operation of the reactor pressure vessel top vent facility will be described.

This reactor pressure vessel top venting equipment 20
Is the main steam isolation valve 2 during normal operation of the BWR plant.
9a, 29b and the motor-operated valves 35, 41 are set to an open state, and the PCV isolation valves 44a, 44b are set to a closed state.

When the reactor is operated, hydrogen gas and oxygen gas are decomposed and produced from the reactor cooling water 24 by the neutron irradiation caused by the nuclear reaction in the core 23, while the fuel rods of the core-loaded fuel assemblies may be generated. There is a radioactive noble gas such as Kr or Xe that may leak in a smaller amount. These non-condensable gases such as hydrogen gas, oxygen gas, radioactive noble gas, etc., are generated by RPV2 during normal operation of the nuclear power plant.
It occurs within 2.

The generated non-condensable gas is mixed with the main steam from the RPV 22, passes through the main steam pipe 27, and passes through the steam turbine 28.
On the other hand, it is discharged from the steam turbine 28 to a condenser (not shown) and is guided to a gas waste treatment system (not shown) attached to this condenser for treatment.

Further, since the electrically operated valves 35 and 41 that are remotely operated during the normal operation of the BWR plant are set to the open state, the RPV vent system 30 and the branch vent system 32 are in the operating state. For this reason, the non-condensable gas in the head portion of the RPV 22 and around the head portion does not flow into the RPV vent system 3
0 RPV vent piping 33 and RPV head spray system 3
A vent flow path communicating with the main steam pipe 27 is formed through the vent branch pipe 40 of the branch vent system 32 that utilizes No. 1.
Therefore, in the vicinity of the head portion of the RPV 22, for example, the RPV
It is possible to prevent the non-condensable gas from accumulating in the head portion of No. 22, the electric valve 35 upstream side piping of the RPV vent system 30, and the check valve 39 downstream side piping of the RPV head spray system 31 in advance. it can.

When the BWR plant is shut down,
The electric valve 41 is closed and the PCV isolation valves 44a and 44b are opened. Therefore, the RPV head spray system 31
When the RPV head spray pipe 38 of No. 2 is also used as the cooling water injection pipe of the reactor isolation cooling facility (hereinafter referred to as RCIC) 43, the RPV 2 is passed through the RPV head spray pipe 38 which is the injection pipe of the RCIC 43 when the reactor is stopped.
It is possible to supply cooling water into the inside of 2 and spray it to cool the gas phase portion 25 of the RPV 22 and reduce the residual pressure of the upper dome.

At the time of this reactor shutdown, R of RCIC43
In the branch vent system 32 branched from the PV head spray pipe 38, since the electric valve 41 is closed, it is possible to return the entire amount of cooling water into the RPV 22. This RCIC4
In order to reliably prevent the cooling water from flowing into the branch vent system 32 during the head spray of the RPV 22, the motor control valve 3 is operated in conjunction with the opening permission signal of the PCV isolation valves 44a and 44b so that the PCV isolation valve is closed. When the opening permission signal is given to 44a and 44b from the central control room or the like, the motor-operated valve 41 may be closed by this opening permission signal.

According to this reactor pressure vessel top vent equipment 20, the non-condensable gas cannot be discharged only by the conventional RPV vent system during normal operation of the nuclear power plant, and the accumulation of the non-condensable gas cannot be prevented. For example, the non-condensable gas from the pipe section on the downstream side of the check valve 39 of the RPV head spray system (RCIC43) 31 can be surely discharged, and the accumulation of gas in the pipe section can be prevented in advance. Moreover,
Even if the non-condensable gas is prevented from accumulating in the downstream piping of the RPV head spray system 31, the cooling function of the RCIC 43 is not impaired, so that reliable and stable operation can be performed.

(Second Embodiment) FIG. 2 is a schematic system diagram showing a second embodiment of a reactor pressure vessel top vent equipment according to the present invention.

In the reactor pressure vessel top vent equipment 20A shown in this embodiment, the structure of the branch vent system 45 is the first.
Reactor pressure vessel top vent equipment 20 shown in the embodiment
Since the second embodiment is basically different from the second embodiment and other configurations and actions are not substantially different, the same reference numerals are given and the description thereof will be omitted.

The reactor pressure vessel top vent equipment 20A shown in FIG. 2 is a check valve 39 of the RPV head spray system 31.
It has a branch vent system 45 branched from the RPV 22 side of the check valve 39 on the downstream side. This branch vent system 45
Comprises a vent branch pipe 46 branched from the RPV head spray pipe 38 of the RPV head spray system 31.
The downstream side of the vent branch pipe 46 is the RPV vent system 30.
Is connected to the RPV vent pipe 33 on the upstream side of a motor-operated valve 35 that is a remotely operated on-off valve. The branch portion of the vent branch pipe 46 is formed at a position as close to the check valve 39 as possible. The RPV head spray piping 38 of the RPV head spray system 31 is a reactor isolation cooling facility (RCI).
C) The injection pipe of 43 may also be used.

This reactor pressure vessel top vent equipment 20A
In the above, the non-condensable gas generated in the RPV22 is
A branch vent system 45 that uses a part of the RPV head spray system 31 even in a portion that cannot be discharged by the RPV vent system 30.
Therefore, it is possible to prevent the non-condensable gas from accumulating around the top of the RPV 22 in advance.

Next, the operation of the reactor pressure vessel top vent equipment will be described.

This reactor pressure vessel top vent equipment 20A
Is the main steam isolation valve 2 during normal operation of the BWR plant.
9a, 29b and the motor operated valve 35 are set to the open state,
The PCV isolation valves 44a and 44b are set to the closed state.

When the reactor is operated, the reactor cooling water 24 is heated by the neutron irradiation due to the nuclear reaction in the core 23 and is vaporized. Non-condensable gases such as oxygen gas and a trace amount of radioactive rare gas are produced from the fuel rods.

The non-condensable gas generated in the RPV 22 is R
While being mixed with the main steam from the PV 22 and being guided to the steam turbine 28 through the main steam pipe 27, the steam is discharged from the steam turbine 28 to a condenser (not shown), and the gas waste attached to this condenser is discarded. A material processing system (not shown) guides and processes.

During normal operation of the BWR plant,
Since the motor-operated valve 35 of the RPV vent system 30 is set to the open state, the RPV vent system 30 and the branch vent system 3
2 is in operation. Therefore, the non-condensable gas in the head portion of the RPV 22 forms a vent flow path leading to the main steam pipe 27 by the branch vent system 45 using the RPV vent system 30 and the RPV head spray system (RCIC43) 31. It is discharged to the steam pipe 27.

Therefore, in the vicinity of the head portion of the RPV 22,
For example, the non-condensable gas is not accumulated in the head portion of the RPV 22, the electric valve 35 upstream side piping portion of the RPV vent system 30, and the check valve 39 downstream side piping portion of the RPV head spray system 31, and is smooth and smooth. To the main steam pipe 27.

When the BWR plant is shut down,
The electric valve 35 of the RPV vent system 30 is closed, and the PCV isolation valves 44a and 44b are opened. By opening the PCV isolation valves 44a and 44b, a part of the cooling water of the cooling system during stop (for example, cooling water in the suppression chamber) is supplied into the RPV 22 through the RPV head spray system (RCIC43) 31 and sprayed. Cooled by RP
The residual pressure of the V22 upper dome has been reduced.

At this time, the RPV head spray system (RCI
Although the branch vent system 45 is branched from C43) 31, the electric valve 35 of the RPV vent system 30 is closed, so that it is possible to reliably prevent the cooling water from flowing into the main steam pipe 27 side, and almost all Are supplied into the RPV 22.

RPV head spray system (RCIC43)
In order to surely close the motor-operated valve 35 of the RPV vent pipe 33 during head spraying of the RPV 22 by 31,
The motor-operated valve 35 can be closed by an opening permission signal for the PCV isolation valves 44a and 44b.

This reactor pressure vessel top vent equipment 20A
Is the RPV vent system 3 during normal operation of the BWR plant.
It is possible to smoothly and smoothly discharge the non-condensable gas at a portion where the non-condensable gas cannot be prevented from being accumulated (discharged) only by 0. The reactor pressure vessel top vent equipment 20A shown in FIG. 2 can also achieve the same effects as the reactor pressure vessel top vent equipment 20 of the first embodiment.

(Third Embodiment) FIG. 3 is a schematic system diagram showing a third embodiment of a reactor pressure vessel top vent equipment according to the present invention.

The reactor vent vessel top vent equipment 20B shown in this embodiment has a branch vent system 50 of FIG.
Since it is basically different from the reactor pressure vessel top vent equipment 20 shown in FIG.
The same reference numerals are given and the description is omitted.

The reactor pressure vessel top vent equipment 20B shown in FIG. 3 is a check valve 3 of the RPV head spray system 31.
9 has a branched vent system 50 branched from the RPV 22 side of the check valve 39. This branch vent system 5
0 is provided with a vent branch pipe 51 branched from the RPV head spray pipe 38 of the RPV head spray system 31,
This vent branch pipe 51 connects the RPV vent system 30 to the RPV.
The vent pipe 33 is connected on the upstream side of the electric valve 35, which is a remote control valve. The branch portion of the branch vent system 50 from the RPV head spray system 31 is provided at a position as close to the check valve 39 as possible.

In this case, the RPV head spray pipe 38 of the RPV head spray system 31 also serves as the injection pipe of the reactor isolation cooling facility 43.

By the way, the branch vent system 50 is provided with an electrically operated valve 52 which is an on-off valve which is remotely operated in the middle of the vent branch pipe 51. The motor-operated valves 52 and 35 of the branch vent system 50 and the RPV vent system 30 are controlled to be opened / closed by, for example, remote operation from the central control room. The motor-operated valves 52 and 35 are opened when the reactor is operating and closed when the reactor is stopped.

The RPV head spray pipe 38 of the RPV head spray system (RCIC43) 31 is closed by closing the motor-operated valve 52 of the branch vent system 50 when the reactor is stopped.
When returning the cooling water to RPV22 using
It can be put back into PV22 and then RPV2
It is preferable to install the motor-operated valve 52 which is a remote control valve from the viewpoint of the reactor water treatment when the upper lid 2 is opened. During the RPV head spray by the RPV head spray system 31,
In order to securely close the motor-operated valve 52, the motor-operated valve 52 is set to P
The CV isolation valves 44a and 44b may be closed by an opening permission signal.

In the reactor pressure vessel top vent equipment 20B shown in FIG. 3 as well, it is possible to eliminate the portion where non-condensable gas may accumulate around the RPV 22 of the BWR plant, and the RPV vent system 30 can be used. It is possible to prevent the accumulation of the non-condensable gas that cannot be discharged during the normal operation of the nuclear reactor, and also to discharge the non-condensable gas from the branch vent system 50.

Next, the operation of the vent facility at the top of the reactor pressure vessel will be described.

During operation of the BWR plant, the electric valve 35 of the RPV vent system 30 and the electric valve 5 of the branch vent system 50
2. Open the main steam isolation valves 29a and 29b,
PCV isolation valves 44a, 4 of the RPV head spray system 31
Set 4b to the closed state.

Since the motor-operated valve 35 of the RPV vent system 30 is opened and the motor-operated valve 52 of the branch vent system 50 is also opened, the main steam pipe 27 from the top of the RPV 22 via the RPV vent system 30 during the reactor operation. In addition to the flow path to
A flow path to the main steam pipe 27 through the branch vent system 50 and the RPV vent pipe 33 is also formed in the check valve 39 downstream side pipe portion of the PV head spray system 31. Therefore, R
Check valve 3 of PV head spray system (RCIC43) 31
9. It is possible to prevent the non-condensable gas from accumulating in the downstream piping portion during the operation of the nuclear reactor.

This reactor pressure vessel top vent equipment 20B
According to this, it is possible to reliably prevent the non-condensable gas generated in the RPV 22 during the normal operation of the BWR plant from staying near the top of the RPV, and it is difficult to discharge the non-condensable gas only by the conventional RPV vent system 30. Accumulation of non-condensable gas at various locations is prevented. In addition, it is necessary to provide the branch vent system 50 with a motor-operated valve 52 that is a remote control valve in order to supply cooling water into the RPV 22 or to operate the RPV 22 when the reactor is shut down.
It is also preferable in operation to remove the top lid of the top.

(Fourth Embodiment) FIG. 4 is a schematic system diagram showing a fourth embodiment of the reactor pressure vessel top vent equipment according to the present invention.

The reactor pressure vessel top vent equipment 20C shown in this embodiment is basically different from the reactor pressure vessel top vent equipment 20 of the first embodiment in the structure of the branch vent system 55, and other Since the configuration and the action are not substantially different, the same reference numerals are given and the description thereof will be omitted.

The reactor pressure vessel top vent equipment 20C shown in FIG. 4 is a check valve 3 of the RPV head spray system 31.
9 has a branch vent system 55 branched from the RPV 22 side of the check valve 39. The branch vent system 55 is an RPV head spray system (RCIC43) 31.
A vent branch pipe 56 branched from the RPV head spray pipe 38 of FIG. The vent branch pipe 56 is provided with an orifice 57 and a motor-operated valve 58 which is a remote control valve on the way, and the downstream side of the motor-operated valve 56 is connected to the RPV vent system 30 at the motor valve 35 upstream side of the RPV vent pipe 33. . The motor-operated valve 35 is also an opening / closing valve that is opened / closed by remote control.

The motor-operated valve 35 of the RPV vent system 30 and the motor-operated valve 58 of the branch vent system 55 are opened while the reactor is operating, while an interlock signal 60 for automatic closing is input when the reactor is stopped, and operation control is performed. Are arranged as described above. The branch portion of the branch vent system 55 from the RPV head spray system 31 is located as close to the check valve 39 as possible.

The RP of the RPV head spray system 31
V head spray pipe 38 is a reactor isolation cooling facility (R
The CIC) 43 may also serve as the injection pipe.

This reactor pressure vessel top vent equipment 20C
When the reactor is in operation, the branch vent system 55 is installed at a portion where the non-condensable gas may accumulate around the RPV 22, so that the non-condensable gas can be prevented from staying. Further, the RPV head spray system 38 is used for the RPV head spray system (RCIC4) in the BWR plant that also serves as the injection piping for the RPV head spray system 31.
3) RPV2 without affecting the cooling function of 31
It is possible to prevent the accumulation of non-condensable gas around the top of No.2.

Next, the vent equipment 20 at the top of the reactor pressure vessel
The action of C will be described.

During normal operation of the BWR plant, the motor-operated valve 35 of the RPV vent system 30 and the motor-operated valve 5 of the branch vent system 55
8 and the main steam isolation valves 29a and 29b are opened, and RP
PCV isolation valves 44a and 44b of the V head spray system 31
Is set to the closed state.

This reactor pressure vessel top vent equipment 20C
Is a flow path from the top of the RPV 22 to the main steam pipe 27 via the RPV vent system 30 and a flow path to the main steam pipe 27 via the branch vent system 55 and the RPV vent pipe 33 during the reactor operation. Is formed.

Therefore, it is possible to prevent the non-condensable gas from accumulating in the piping portion on the downstream side of the check valve 39 of the RPV head spray system 31 during the operation of the reactor.

Further, when the cooling water is returned to the RPV 22 via the RPV head spray system 31 when the reactor is stopped, it is possible to return the entire amount of the returned water to the RPV 22 by closing the electric valve 58 of the branch vent system 55. Is. From this point of view, it is preferable to provide the branch vent system 55 with the electric valve 58 from the viewpoint of treating the reactor water when the upper lid of the RPV 22 is opened.

Branch vent system 5 during RPV head spray
In order to surely close the motor-operated valve 58 of No. 5, the PCV isolation valves 44a and 44b may be controlled to be closed by the opening permission signal.

Furthermore, when the RPV head spray system 31 operates during normal reactor operation, the orifice 57 is used to prevent transfer of the cooling water to the branch vent system 55 immediately after the operation as much as possible, and the branch vent system 55 is operated. The motor-operated valve 58 and the motor-operated valve 35 of the RPV vent system 30 are closed by receiving the automatic closing signal 60 by the activation of the RPV head spray system 31, so that the RPV head spray system (RCIC 43) 3
There is no problem in the function of injecting the cooling water through the RPV head spray pipe 38 of No. 1.

Although the RCIC 43 operates in the surveillance test mode even during the reactor operation, the motor valve 35 of the RPV vent system 30 and the motor valve 58 of the branch vent system 55 are closed during the surveillance operation. Consideration such as bypassing the signal is required.

This reactor pressure vessel top vent equipment 20C
According to this, during the operation of the BWR plant, it is possible to smoothly and smoothly discharge the non-condensable gas around the RPV 22 in a portion that cannot be discharged only by the operation of the conventional RPV vent system 30. It is preferable to provide the branch vent system 55 with the orifice 57 and the motor-operated valve 58 in terms of operation when the reactor is stopped.

(Other Examples) In each embodiment of the reactor pressure vessel top vent equipment according to the present invention, the RPV is used.
The head spray pipe 38 is an RPV head spray system (R
The CIC 43) 31 also serves as the cooling water injection pipe, and in the third and fourth embodiments, the branch vent system is connected to the RPV vent system 30 at the upstream side of the motor-operated valve 35. The vent system may be installed downstream of the motor-operated valve 35 of the RPV vent system 30. However, the branch vent system 46 of the second embodiment needs to be connected to the upstream side of the electric valve 35 of the RPV vent system 30. This is to prevent the cooling water from returning to the main steam pipe side when the reactor is shut down.

In the fourth embodiment, the motor-operated valve 58 of the branch vent system 55 and the motor-operated valve 35 of the RPV vent system 30 are closed according to the cooling water injection start time after the activation signal of the RPV head spray system (RCIC43) 31. If the time is fast, then the installation of the orifice is not necessary. This is because there is no problem in the cooling water injection function of the RPV head spray system (RCIC43) 31.

In the BWR plant in which the injection pipe of the RCIC 43 is also used as the RPV head spray pipe 38 of the RPV head spray system 31, the vent branch pipe 56 of the branch vent system 55 may be connected to the main steam pipe 27.

Further, the vent equipment at the top of the reactor pressure vessel can be used as the vent equipment around the reactor vessel of the PWR plant.

[0081]

EFFECTS OF THE INVENTION In the reactor pressure vessel top vent equipment according to the present invention, a reactor pressure vessel vent system and a branch vent system utilizing a reactor pressure vessel head spray system are provided to the vicinity of the reactor pressure vessel top. Accumulation of non-condensable gas can be prevented efficiently and reliably, and reliable and stable operation can be performed.

Even when the reactor pressure vessel head spray system is also used as the injection pipe of the reactor isolation cooling equipment, non-condensable gas is accumulated in the vicinity of the top of the reactor pressure vessel during normal operation of the reactor. By the cooperation of the reactor pressure vessel vent system and the branch vent system, it prevents it in advance and surely, and fully demonstrates the injection cooling function without impairing the injection cooling function during operation of the reactor isolation cooling system, Can be maintained.

Further, the branch vent system can efficiently and effectively perform the exhaust process of the non-condensable gas in the part which cannot be exhausted by the reactor pressure vessel vent system, and the non-condensable property is provided around the top of the reactor pressure container. It is possible to prevent gas from accumulating in advance.

[Brief description of drawings]

FIG. 1 is a schematic system diagram showing a first embodiment of a reactor pressure vessel top vent facility according to the present invention.

FIG. 2 is a schematic system diagram showing a second embodiment of a reactor pressure vessel top vent facility according to the present invention.

FIG. 3 is a schematic system diagram showing a third embodiment of a reactor pressure vessel top vent facility according to the present invention.

FIG. 4 is a schematic system diagram showing a fourth embodiment of a reactor pressure vessel top vent facility according to the present invention.

FIG. 5 is a schematic system diagram of a gas treatment facility of a conventional nuclear power plant.

[Explanation of symbols]

20, 20A, 20B, 20C Reactor pressure vessel top vent equipment 21 Reactor containment vessel (PCV) 22 Reactor pressure vessel (RPV) 23 Core 24 Reactor cooling water (liquid phase portion) 25 Gas phase portion (steam phase portion) ) 27 main steam pipe 28 steam turbines 29a, 29b main steam isolation valve 30 reactor pressure vessel vent system (RPV vent system) 31 reactor pressure vessel head spray system (RPV head spray system) 32 branch vent system 33 reactor pressure vessel Vent piping (RPV vent piping) 34 Reactor pressure vessel head vent nozzle (RPV head vent nozzle) 35 Motorized valve (remotely operated valve) 36 Reactor pressure vessel head spray nozzle (RPV head spray nozzle) 37 Dry well 38 Reactor pressure Container head spray piping (RPV head spray piping) 39 Check valve 40 Vent Branch piping 41 Motorized valve (remote control valve) 43 Reactor isolation cooling equipment (RCIC) 44a, 44b Reactor containment vessel isolation valve (PCV isolation valve) 45, 50, 55 Branch vent system 46, 51, 56 Vent branch piping 52,58 Electric valve (remote control valve) 57 Orifice

Continued front page    (72) Inventor Akio Shioiri             8th Shinsugita Town, Isogo Ward, Yokohama City, Kanagawa Prefecture             Ceremony company Toshiba Yokohama office

Claims (7)

[Claims] 1. A reactor pressure vessel head spray system for supplying cooling water to a reactor pressure vessel head spray nozzle above a reactor pressure vessel, and an atom for guiding a non-condensable gas generated during reactor operation to a main steam pipe. In a reactor pressure vessel with a reactor pressure vessel vent system, the reactor pressure vessel head spray system is branched from the reactor pressure vessel side of the check valve provided on the reactor pressure vessel head spray pipe. A branch vent system, which is configured to guide the non-condensable gas generated in the reactor pressure vessel to the main steam pipe side together with the reactor pressure vessel vent system. Vent equipment on top of pressure vessel. 2. The branch vent system comprises a vent branch pipe branched from a reactor pressure vessel head spray pipe of a reactor pressure vessel head spray system, and the vent branch pipe has an on-off valve which is remotely operated on the way. The reactor pressure vessel top vent equipment according to claim 1, which is connected to the main steam pipe side through the vent pipe. 3. The branch vent system comprises a vent branch pipe branched from a reactor pressure vessel head spray pipe of a reactor pressure vessel head spray system, and the vent branch pipe is a reactor of the reactor pressure vessel vent system. The reactor pressure vessel top vent facility according to claim 1, which is connected to the pressure vessel vent pipe on the upstream side of an on-off valve provided in the reactor pressure vessel vent pipe. 4. The branch vent system comprises a vent branch pipe branched from a reactor pressure vessel head spray pipe of a reactor pressure vessel head spray system, and this vent branch pipe has a downstream side of the reactor pressure vessel vent system. The reactor pressure vessel top vent equipment according to claim 1, wherein an on-off valve that is remotely operated is provided in the middle of the vent branch pipe while being connected to the reactor pressure vessel vent pipe. 5. The branch vent system comprises a vent branch pipe branched from a reactor pressure vessel head spray pipe of a reactor pressure vessel head spray system, and this branch pipe has a downstream side of an atom of the reactor pressure vessel vent system. The reactor vent vessel top venting facility according to claim 1, wherein the vent valve top pipe is connected to the reactor pressure vessel vent pipe, and a remotely operated opening / closing valve and an orifice are provided in the middle of the vent branch pipe. 6. The reactor pressure vessel head spray system comprises reactor containment vessel isolation valves inside and outside the reactor containment vessel of the reactor pressure vessel head spray pipe, while the reactor pressure vessel head spray system is provided. The reactor pressure vessel top venting equipment according to any one of claims 1 to 5, wherein the piping is configured so as to also serve as an injection piping of the reactor isolation cooling equipment. 7. The on-off valve provided in the vent branch pipe of the branch vent system is configured to be closed by an opening permission signal of the reactor containment isolation valve of the reactor pressure vessel head spray system. The reactor vent vessel top vent facility according to 4 or 5.