JPH0534491A - Cut valve for separation valve of instrumentation system in reactor core - Google Patents

Abstract

PURPOSE:To ensure holding unless a point not specified of a cutting blade is broken by residual energy after a detector cable is cut, and thus a sealing function is lost. CONSTITUTION:A notch part 36 is provided on a specified point of a cutting blade 13 so that a specified point of the blade is easily broken. After a detector cable 20 is cut, the specified point is broken and the cutting blade 13 is seated to a valve seat 21, and is closely connected to a valve seat 34, and sealing characteristic is not defected. The position of the notch part 36 comes below a valve seat 3 which does not affect sealing function after the cutting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving in-core instrumentation (hereinafter referred to as T
The isolation valve for the isolation valve of the in-core instrumentation system that constitutes the boundary of the containment vessel of the nuclear reactor containment vessel.

[0002]

2. Description of the Related Art As shown in FIG. 5, a TIP system is provided with a plurality of output area detectors 2 arranged at predetermined positions in a reactor pressure vessel 1 and internally provided in these output area detectors 2. A calibration tube 3 and a detector guide tube 4 connected to its lower end,
An indexing device 5, an isolation valve 8 including a ball valve 8a and a cutoff valve 8b, through which a detector guide tube 4 drawn out of the reactor containment vessel 7 through a penetration flange 6 penetrates, and a shielding vessel 9
And a detector driving device 10.

A TIP detector (not shown) is attached to the tip of a detector cable 20 (not shown) which passes through the detector guide tube 4, and is housed in a shielding container 9 when not in use. The instrument cable is wound on a reel in the detector driving device 10.

On the other hand, when measuring the neutron flux in the reactor pressure vessel 1, the TIP detector is sent into the detector guide tube 4 by the detector cable 20 unwound from the reel of the detector driving device 10. .. The TIP detector advances in the detector guide tube 4 by the length of the sent detector cable 20. When the TIP detector exits the shielding container 9, the ball valve 8a of the isolation valve 8 opens, the TIP detector is introduced into the reactor containment vessel 7 through the isolation valve 8, and finally the core top portion of the calibration tube 3 is introduced. Then, the operation is stopped and the extraction operation is started to measure the neutron flux in the reactor pressure vessel 1. In this state, an abnormality occurs in the reactor and an isolation signal for the reactor containment vessel 7 is transmitted. However, since the detector guide tube 4 and the detector cable 20 penetrate the cutoff valve 8b in this way. The ball valve 8a cannot be closed. In such a case, the cutting blade provided in the cutting valve 8b is operated to disconnect the detector guide tube 4 from the detector cable inserted into the guide tube 4, and at the same time, the detector guide tube 4 is cut. The TIP-based containment vessel penetrating portion is isolated by sealing the cut end of the above with a cutting blade.

The conventional cutoff valve 8b will be described with reference to FIG. As shown in FIG. 6, a conventional cutting valve 8b is provided with a cylinder 12 in a valve box 11, and a piston 14 having a cutting blade 13 mounted downward is incorporated in the cylinder 12 and a cylinder above the piston 14 is installed. Gunpowder 15 in 12 openings
A gunpowder plug 16 filled with is provided. A valve seat 21 is provided below the cylinder 12, and a through hole 17 for penetrating the detector guide tube 4 is provided in a direction perpendicular to the cutting blade 13. The outside of the detector guide tube 4 which penetrates the through hole 17 is fixed to the valve box 11 and the valve seat 21 by a guide tube outlet plug 18 (outlet side) and a guide tube inlet plug (inlet side). Valve box
Reference numeral 11 also serves as a holder for holding the detector guide tube 4.

To operate the cutoff valve 8b, a coil (not shown) provided in the explosive charge 15 of the explosive charge plug 16 is energized to explode the explosive charge 15, and the pressure causes the piston 14 to move downward in the cylinder 12. The cutting blade 13 is slid in the direction to drive the cutting blade 13 toward the detector guide tube 4, and the detector guide tube 4 and the detector cable 20 inserted therein are both cut off, and the tip of the cutting blade 13 is moved to the valve seat 21. Abutting, the through hole 17 at the plane of the cutting blade 13
To block.

[0007]

However, the conventional isolation valve cutoff valve 8b has the following problems. (1) It is necessary to notify or authorize a person in charge of handling dangerous materials and a related organization for handling the explosive 15 to the driving source of the cutting blade 13. (2) If explosive powder 15 is accidentally exploded during inspection and repair, workers may be at risk. (3) Once the explosive plug 16 is used once, the inner wall of the piston 14 and cylinder 12 will be burned with explosive powder and cannot be reused.Therefore, the operation confirmation test cannot be performed during repeated cuts or during periodic inspections, resulting in reduced reliability. .. (4) The detector cable 20 is usually made of a material such as piano wire (SW
P, SWPR, etc.) are used, and a cutting blade 13 for cutting this
Is made of alloy tool steel with higher strength and hardness (SKS
Etc.) are used. When the cutoff valve 8b is operated, the detector cable 20 can be sufficiently disconnected. However, since energy still remains in the cutting blade 13 after the disconnection of the detector cable 20, the cutting blade 13 collides with the inner bottom portion of the valve box 11 and the cutting blade 13 itself may be damaged by the impact force at that time. In such a case, since the damaged position of the cutting blade 13 cannot be specified, the valve seat function of the cutting blade 13 itself after the disconnection of the detector cable 20 is lost and the isolation function cannot be maintained.

The present invention has been made to solve the above-mentioned problems, and its purpose is to use the detector cable 20 alone or to use the detector guide tube 4 and the detector without using explosive as a driving source of the cutting blade 13. In-core instrumentation capable of simultaneously disconnecting the cable 20 and further maintaining the function of the isolation valve 8 because the tip of the cutting blade 13 is damaged at a specific location when the detector cable 20 is disconnected. The purpose of the present invention is to provide a disconnect valve for a system isolation valve.

[0009]

According to the present invention, there is provided a valve box, a cylinder formed in the valve box, a piston that slides in the cylinder, and a cutting blade attached to the end of the piston. Isolation of an in-core instrumentation system including a detector cable or detector guide tube provided in a direction substantially perpendicular to the sliding direction of the piston and communicating with the end portion of the cylinder, and a through hole penetrating the detector cable. In the valve cutoff valve, the inside of the cylinder is pressurized by electric discharge to slide the piston, and the cutting blade is configured to cut off both the detector cable or the detector guide tube and the detector cable. The cutting blade is characterized in that a notch portion is formed at a position below the valve seat so that the sealing function is not impaired when the cutting blade is seated in the valve box after the detector cable is disconnected.

[0010]

[Function] When the capacitor equipment is charged and the discharge switch is turned on after charging, a discharge phenomenon occurs, a shock wave acts on the upper part of the piston, the cutting blade attached to the piston descends in the cylinder, and the detector cable Only, or both the detector guide tube and the detector cable can be disconnected at the same time.

Further, when the cutting valve operates, the cutting blade cuts the detector cable into both sides, and the cutting blade collides with the bottom of the valve box.
The impact force at that time is absorbed (damaged) by the notch. Due to this damage, damage always occurs in a specific portion (a portion that does not affect the valve seat function) and the valve seat function is maintained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the isolation valve for a isolation valve according to the present invention will be described with reference to FIGS. In addition, in each figure, FIG.
Also, the same portions as those in FIG. 6 or portions having the same function are denoted by the same reference numerals and described. As shown in FIG. 1, the cutoff valve in the present embodiment is provided with a discharge plug 22 for discharging and pressurizing the upper opening of the cylinder 12 in the valve box 11. A pair of electrodes 23 is provided in the discharge plug 22. A wire 38 is connected between the electrodes 23. A cylinder 12 is formed in the valve box 11, and a piston 14 is incorporated in the cylinder 12. A cutting blade 13 is attached to the tip of the piston 14. A through hole 17 is provided so as to communicate with the lower portion of the cylinder 12 in the valve box 11 in a direction perpendicular to the cutting blade 13, and a valve seat 21 is provided below or below the through hole 17. The detector cable 20 has through holes 24a, 25a of an outlet flange 24 and an inlet flange 25, which are joints of the detector guide pipe 4 provided on both sides of the valve box 11 so as to face each other.
And through the through hole 17 of the valve box 11. A valve seat 34 that seals the through hole 17 when the cutting blade 13 descends is interposed below the cylinder 12 and the valve seat 21 in the valve box 11. Gasket 35 is interposed between the contact surface between valve box 11 and outlet flange 24 and the contact surface between valve box 11 and inlet flange 25 to maintain airtightness. As shown in the enlarged view of FIG. 2, the cutting blade 13 has a notch 36 formed at the cutting edge.
The notch 36 is formed so as to be located below the valve seat 34 after the detector cable 20 is cut off as shown in FIG.

The electrode 23 of the discharge plug 22 is connected by a lead wire 26 to an electricity storage facility required for discharging, for example, a capacitor facility 27. This capacitor equipment 27 is separately installed outside. As shown in FIG. 3, the charging and discharging circuit of the capacitor equipment 27 includes a DC power source 28, a resistor 29, a capacitor 30,
It is composed of an electrode 23, a switch S ₁ 31 and a switch S ₂ 32. Note that FIG. 4 shows only a main part of the state where the cutoff valve in FIG. 1 cuts the detector cable.

The operation of the isolation valve cutoff valve of the in-core instrumentation system of the present invention constructed as described above will be described. As shown in FIG. 5, the detector cable sent by the detector driving device 10 exits the shielding container 9 and leaves the isolation valve 8 (ball valve 8).
a, the cutoff valve 8b), the indexing device 5, and the calibration tube 3
Inserted in. At that time, when the containment vessel isolation signal is transmitted, the detector driving device 10 automatically pulls out and drives the detector cable, but if the detector driving device 10 fails at this time, the detector cable is pulled out. Therefore, the ball valve 8a of the isolation valve 8 cannot be closed. In such a case, the condenser equipment 27
As shown in FIG. 3, the switch S ₁ 31 is closed and a direct current is applied to charge the capacitor 30, and thereafter,
By turning on the switch S ₂ 32 for starting the discharge, a discharge phenomenon occurs due to the electrode 23 in the discharge plug 22. At this time,
As shown in FIG. 4, a shock wave is generated on the upper surface of the piston 14, and the discharge pressure applied to the air causes the piston 14 to slide downward. As the piston 14 descends, the cutting blade 13 descends to move the detector cable 20 to the detector cable 20. Can be cut off.

That is, the capacitor equipment is operated by the isolation signal.
Charging is started at 27, and after several seconds, discharge is started at the discharge plug 22, the piston 14 descends, and the detector cable 20 is cut by the cutting blade 13. After that, the cutting blade 13 is further lowered by the remaining power of the discharge energy, and is seated on the valve seat 21 and, at the same time, receives an impact force. This impact force is released when the weakest part of the cutting blade 13 (the part of the notch 36) is damaged.
Since the notch 36 is located below the valve seat 34, even if it is damaged (a crack is generated from the notch), it does not affect the sealing function.

In the conventional disconnecting valve, however, it was possible to disconnect the cable when the detector cable was disconnected, but after the disconnection, the cutting blade inside the disconnecting valve was damaged at an unspecified position,
Depending on the breakage position, the valve seat 34 cannot be completely seated,
The seal is not maintained. On the other hand, the breakage position is specified by using the cutting blade according to the present embodiment, and after the cable is cut off, the valve seat 21 is firmly seated together with the closeness to the valve seat 34, and the isolation valve function of the cutting valve is provided. Will be improved.

[0017]

The present invention has the following effects. (1) It is possible to provide a cutting valve for isolation valve having the same function as the conventional one, without using explosive as a driving source of the cutting blade. (2) Since explosives are not used as compared with conventional ones, it is not necessary to notify or approve the hazardous materials handling personnel and related organizations. (3) Reliability can be improved because an operation confirmation test can be performed at the annual inspection. (4) In the unlikely event of a reactor primary cooling water leak,
It has a fail-safe function that can close the valve even if the heater fails. (5) If the cutting blade is damaged after disconnecting the detector cable, the damaged part can be identified, and the isolation valve function can be reliably maintained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of an isolation valve cutoff valve according to the present invention in a partial block.

FIG. 2 is an enlarged side view showing a cutting blade of the cutting valve in FIG.

FIG. 3 is an electric circuit diagram of a capacitor facility used for the cutoff valve in FIG.

4 is a vertical cross-sectional view showing only a main part of the state of the cutoff valve in FIG.

FIG. 5 is a diagram showing a mobile in-core instrumentation (TI) to which the present invention is applied.
Schematic showing the P) system.

FIG. 6 is a vertical cross-sectional view showing a conventional isolation valve cutoff valve for an in-core instrumentation system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel, 2 ... Output area detector, 3 ... Calibration tube, 4 ... Detector guide tube, 5 ... Indexing device, 6 ... Penetration flange, 7 ... Reactor containment vessel, 8 ... Isolation valve, 9 … Shielded container, 10… Detector drive, 11… Valve box, 12… Cylinder, 13
… Cutting blade, 14… Piston, 15… Gunpowder, 16… Gunpowder plug,
17 ... Through hole, 18 ... Guide tube outlet plug, 19 ... Guide tube inlet plug, 20 ... Detector cable, 21 ... Valve seat, 22 ... Discharge plug, 23 ... Electrode, 24 ... Outlet flange, 25 ... Inlet flange,
26 ... Lead wire, 27 ... Capacitor equipment, 28 ... DC power supply, 29
... resistance, 30 ... capacitor, 31 ... switch S _1, 32 ... switch S _2, 33 ... liquid, 34 ... valve seat, 35 ... gasket,
36 ... Notch, 37 ... O-ring, 38 ... Wire.

Claims (1)

Claim: What is claimed is: 1. A valve box, a cylinder formed in the valve box, a piston that slides in the cylinder, a cutting blade attached to an end portion of the piston, and Isolation valve for in-core instrumentation system including a detector cable or detector guide tube provided in a direction substantially perpendicular to the sliding direction of the piston and communicating with the end portion of the cylinder, and a through hole penetrating the detector cable In the cutting valve for pressurization, the inside of the cylinder is pressurized by electric discharge to slide the piston, and the cutting blade cuts off the detector cable or the detector guide tube and the detector cable. For the isolation valve of the in-core instrumentation system, the blade has a notch at a position below the valve seat that does not impair the sealing function when seated in the valve box after the detector cable is disconnected Off Valve.