JP3138936B2 - Apparatus and method for controlling pneumatic main steam isolation valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic main steam isolation valve control apparatus and method for controlling the opening and closing of a pneumatic main steam isolation valve disposed in a main steam pipe in a nuclear power plant such as a boiling water type. About.

[0002]

2. Description of the Related Art In a nuclear power plant of a boiling water type or the like, a main steam pipe is provided for guiding high-temperature and high-pressure steam generated in a reactor pressure vessel to a turbine. Pneumatic main steam isolation valves are installed inside and outside the vessel. This pneumatic main steam isolation valve is required to be rapidly closed at a predetermined time in an emergency or the like. The pneumatic main steam isolation valve is provided with air control equipment for each valve.This pneumatic control equipment is designed to minimize the waste time such as the delay in operating time of the pneumatic main steam isolation valve. It is placed directly on the cylinder of the steam isolation valve.

[0003]

However, since the pneumatic main steam isolation valve is installed in a narrow location such as in the reactor containment vessel, the air control equipment is placed directly on the pneumatic main steam isolation valve. In this case, there is a disadvantage that the pneumatic main steam isolation valve occupies a large space and the working space is limited.

Further, since the operation time of the pneumatic main steam isolation valve is severely restricted, a solenoid valve, a two-way valve, a three-way valve, and a solenoid valve in the air control equipment for controlling the operation of the pneumatic main steam isolation valve are provided. The four-way valve and the like are dispersed and arranged directly on the pneumatic main steam isolation valve, and a lot of time is required for maintenance work of the air control equipment. Therefore, recently, in order to facilitate maintenance work on air control equipment, air control equipment for the pneumatic main steam isolation valve consisting of a solenoid valve, two-way valve, three-way valve, and four-way valve has been integrated.
Combination is required, but there is a drawback that the air control equipment becomes large when integrated and combined.

An object of the present invention is to provide a control device and a control method for a pneumatic main steam isolation valve which can secure a work space for maintenance work even if the air control equipment becomes large due to integration and compounding. To provide.

[0006]

In order to achieve the above object, a pneumatic main steam isolation valve control device according to the present invention includes an air control device for controlling the opening and closing of a pneumatic main steam isolation valve. A steam isolation valve is separately provided, and an air cylinder of the pneumatic main steam isolation valve and the air control equipment are connected via an air pipe.

[0007] The length of the air pipe is set to a size such that when the volume of the air pipe and the pressure loss coefficient are adjusted, the operation time of the pneumatic main steam isolation valve is within a predetermined time; In addition, a flexible tube is provided at at least one position at an end or in the middle of the air pipe.

Further, the air control equipment is installed on an earthquake-resistant structure.

Further, the air control equipment according to the present invention is separated from the pneumatic main steam isolation valve and connected to an air cylinder of the pneumatic main steam isolation valve via an air pipe.

In the method for controlling a pneumatic main steam isolation valve according to the present invention, the pneumatic main steam isolation valve is connected to an air cylinder of the pneumatic main steam isolation valve via an air pipe, and is provided separately from the pneumatic main steam isolation valve. The opening and closing of the pneumatic main steam isolation valve is controlled by air control equipment.

[0011]

According to the above construction, the air control equipment can be separated from the pneumatic main steam isolation valve and installed in another wide place. In addition, a large work space for maintenance work can be secured.

When the air control equipment is separately installed, the operation time T of the main steam isolation valve changes. However, by adjusting the volume and the pressure loss coefficient of the air pipe, the operation time T can be set within the predetermined time. I do. Specifically, the operating time T of the pneumatic main steam isolation valve is mainly adjusted by adjusting the air pipe volume.
(= T ₀ + T ₁ (T ₀ : delay time, T ₁ : actual operation time)), the delay time T ₀ is determined and the pressure loss coefficient of the air pipe is adjusted, so that the delay time T ₀ and the actual operation time to determine the T _1.
In this way, the operation time of the pneumatic main steam isolation valve can be set within a predetermined time even in a separately installed air control facility.

Further, since the flexible tube is provided at the end or in the middle of the air pipe, even if the pneumatic main steam isolation valve is displaced by heat or the like, the displacement is absorbed to prevent distortion of the air pipe. be able to.

[0014] Further, by installing the air control equipment on the earthquake-resistant structure, damage during an earthquake is prevented. In this case, the above-mentioned earthquake-resistant structure needs to have the same earthquake-proof function as the pneumatic main steam isolation valve.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. First, the structure and operating principle of the pneumatic main steam isolation valve will be described in detail. As shown in FIG. 3, the pneumatic main steam isolation valve 1
Is a cylinder type Y-type globe valve having an air cylinder 2, an oil cylinder 3, and a spring 4. The air control equipment 5 minimizes the volume of an air pipe (not shown) to the air cylinder 2 and delays time. Is set directly on the air cylinder 2 in order to minimize. Although not shown, a solenoid valve, a two-way valve, a three-way valve, and a four-way valve are installed in the air control equipment 5. The air control equipment 5 has an air supply pipe 6
Are connected and receive supply air S / A from an air source.
In the drawings, reference numeral 7 denotes a valve body, 8 denotes a valve rod, and 9 denotes a valve box.

In the normal operation, the pneumatic main steam isolation valve 1 is fully opened by supplying compressed air from an air source to the lower air cylinder 2b via the air control equipment 5. In an emergency, a closing signal is input to the air control equipment 5, and the solenoid valve, two-way valve, three-way valve, and four-way valve on the air control equipment 5 are switched, and the compressed air from the air control equipment 5 is supplied to the upper air cylinder 2a. Supplied and lower air cylinder 2
The compressed air in the area b is rapidly exhausted, and the urging force of the spring 4 is applied to rapidly close the valve to bring it into a fully closed state as shown in the figure. The opening / closing time at the time of sudden closing can be adjusted by a throttle valve attached to the oil cylinder 3.

The pneumatic main steam isolation valve 1 includes an oil cylinder 3
Therefore, unlike other pneumatic cylinder valves, it is possible to immediately start the constant velocity movement immediately after the operation delay time T ₀ of the pneumatic cylinder after the input of the operation signal.

In the pneumatic main steam isolation valve 1 having such features, the solenoid valve, the two-way valve, the three-way valve, and the four-way valve are arranged in a dispersed manner. Then, the air control equipment 5 becomes large and cannot be installed in a narrow space. Therefore, in this embodiment, as shown in FIG. 1, the air control equipment 5 is provided separately from the pneumatic main steam isolation valve 1.

In FIG. 1, the air control equipment 5 is, as with the pneumatic main steam isolation valve 1, separately provided on a seismic rack 10 for maintaining the seismic function during an earthquake. An air pipe 11 connects between the air control equipment 5 on the seismic rack 10 and the upper and lower air cylinders 2a and 2b of the pneumatic main steam isolation valve 1. A flexible tube 12 is provided at an end portion or at least one position in the middle of the air pipe 11, and even if the pneumatic main steam isolation valve 1 is displaced by heat or the like,
The displacement is absorbed to prevent the air pipe 11 from being distorted.

In the pneumatic main steam isolation valve 1 and the air control equipment 5, the operation time delay and the like are reduced so far to facilitate the adjustment of the operation time of the strictly controlled pneumatic main steam isolation valve. ing. As in the present embodiment, the air control equipment 5
Is separated from the pneumatic main steam isolation valve 1, the air piping volume v between the air control equipment 5 and the pneumatic main steam isolation valve 1
In particular, by suppressing the pressure loss of the air pipe 11 and the volume vb of the air pipe 11b connecting the air control equipment 5 and the lower air cylinder 2b of the pneumatic main steam isolation valve 1,
The operation time of the pneumatic main steam isolation valve 1 can be easily adjusted.

That is, the volume vb of the air pipe 11b and the volume V in the lower air cylinder 2b of the pneumatic main steam isolation valve 1
The sum of b has the following relationship with the time until the pneumatic main steam isolation valve 1 starts operating in an emergency, that is, the operation delay time T ₀ .

T ₀ = k ₀ (Vb + vb) k ₀ ; proportionality constant The pressure loss coefficient f of the air pipe 11 has the following relationship between the operation delay time T ₀ and the actual operation time T ₁ .

T ₀ = k ₀ ′ √ (1 + f) T ₁ = k ₁ √ (1 + f) k ₀ ′,
k ₁ ; proportionality constant By the way, Vb = 6.8 × 10 ⁴ cc, vb = 1.7 × 10 ⁴
The operation time delay of the pneumatic main steam isolation valve was evaluated by the above equation and experiments using the air main steam isolation valve with cc, f = 0.16, the separately installed air control equipment and the air piping communicating between them. . The result is shown in FIG.

In FIG. 2, in the pneumatic main steam isolation valve having the direct-installed air control equipment, the operation delay time T ₀ = 0.22.
Second, the actual operation time T ₁ = 3.24 seconds, and when the above-mentioned separate air control equipment is installed in this pneumatic main steam isolation valve, T ₀
= 0.30 seconds and T ₁ = 3.48 seconds. As a result of the experiment, T ₀ = 0.31 seconds and T ₁ = 3.54 seconds, and the evaluation result and the experimental result were almost the same. From the above results, in the pneumatic main steam isolation valve, if the operation characteristics (operation delay time T ₀ , actual operation time T ₁ ) when the air control equipment 5 is directly placed (the state of FIG. 3) are known. , Separate air control equipment 5
From the characteristics (piping volume v and pressure loss f) of the air pipe 11 connecting the air-operated main steam isolation valve 1 to the main steam isolation valve 1 having the separately installed air control equipment 5 (the state of FIG. 1),
The operating time can be adjusted within the required operating time.

Further, in adjusting the oil cylinder,
Since it is possible to adjust the actual operating time T _1, the actual operating time T ₁ may be a common to straight Place / separately installed air control equipment, change to a different place air control equipment straight every air control equipment However, the operation time difference of the pneumatic main steam isolation valve is only the operation time delay, and the total operation time of the pneumatic main steam isolation valve is as small as about 0.3 seconds.
It only increases by one second.

According to this embodiment, the air control equipment attached to the pneumatic main steam isolation valve is integrated and combined to obtain an operating characteristic which is almost the same as that of the direct installation even if the air control equipment is enlarged. be able to.

[0027]

As described above, according to the present invention,
Since the air control equipment can be installed in a wide place different from the pneumatic main steam isolation valve, it is possible to improve workability in maintenance of the air control equipment.

Further, since the air pipe is provided with a flexible tube, even if the pneumatic main steam isolation valve is displaced by heat or the like, the displacement can be absorbed, and damage to the air pipe can be prevented. .

Furthermore, since the air control equipment is installed on the earthquake-resistant structure, safety against earthquakes can be guaranteed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a control device for a pneumatic main steam isolation valve of the present invention.

FIG. 2 is a diagram comparing the operation time of the pneumatic main steam isolation valve between the present invention and the prior art.

FIG. 3 is a schematic configuration diagram of a conventional pneumatic main steam isolation valve control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pneumatic main steam isolation valve 2 Air cylinder 2a Upper air cylinder 2b Lower air cylinder 3 Oil cylinder 4 Spring 5 Air control equipment 6 Air supply piping 7 Valve body 8 Valve rod 9 Valve box 10 Seismic rack 11 Air piping 11a Upper air piping 11b Lower air pipe 12 Flexible tube

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G21D 1/00 G21D 3/04

Claims (6)

(57) [Claims] An air control device for controlling the opening and closing of a pneumatic main steam isolation valve is provided separately from the pneumatic main steam isolation valve, and an air cylinder of the pneumatic main steam isolation valve and the air control are provided. A pneumatic main steam isolation valve controller, wherein the equipment is connected via an air pipe. 2. The pneumatic main steam isolation valve control device according to claim 1, wherein the length of the air pipe is adjusted when a volume of the air pipe and a pressure loss coefficient are adjusted. The pneumatic main steam isolation valve control device is set to a size such that the operation time of the air main steam isolation is within a predetermined time. 3. The pneumatic main steam isolation valve control device according to claim 1, wherein at least one flexible tube is provided at an end or in the middle of the air pipe. Steam isolation valve controller. 4. The control device for a pneumatic main steam isolation valve according to claim 1, wherein said air control equipment is installed on an earthquake-resistant structure. 5. An air control system which is separated from the pneumatic main steam isolation valve, connected to an air cylinder of the pneumatic main steam isolation valve via an air pipe, and controls opening and closing of the pneumatic main steam isolation valve. . 6. The pneumatic main steam isolation valve is connected to an air cylinder of the pneumatic main steam isolation valve via an air pipe, and air control equipment is provided separately from the pneumatic main steam isolation valve. A method for controlling a pneumatic main steam isolation valve, comprising controlling opening and closing.