JPH09145887A - Travelling in-core instrumentation explosive cutting valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent leak due to conductive combustion residue generated in a power cartridge when a travelling in-core instrumentation explosive cutting valve is operated by covering the explosive storing guide inner wall surface of a power cartridge with an electric insulation layer. SOLUTION: A power cartridge 13 is adapted to store igniter powder 24 and loading powder 25 in a metallic cartridge body 21. A heating electrode 23 connected between pin electrodes 22a, 22b supported by an insulating support 31 generates heat, thereby igniting explosive 24 for covering the electrode to explode the explosive 25. At this time, the explosive storing chamber inner wall surface 21a in the body 21 is covered with a cylindrical insulating sleeve 27. Accordingly, as the sleeve 27 is interposed between the current carrying electrodes 22a, 22b and the body 21, even if conductive combustion residue is generated by ignition and explosion of explosives 24, 25, it is possible to prevent electric formation between the electrodes 22a, 22b due to the combustion residue so as to prevent the occurrence of leak.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile in-core instrumentation (TIP) from outside the containment vessel to the inside of the reactor for calibrating a local power range neutron flux detector for in-core neutron flux monitoring.
The TIP detector cable in the nuclear reactor instrumentation system in which the detector cable is inserted and pulled out and the TIP guide tube for guiding the same are cut by a cutter that is pushed forward by the explosive force of the explosive to isolate the instrumentation system. The present invention relates to a movable in-core instrumented explosive disconnect valve.

[0002]

2. Description of the Related Art In a nuclear power plant using a boiling water reactor, a TIP explosive cutoff valve is provided in order to disconnect the TIP detector cable and the TIP guide tube of a TIP drive system to isolate the system when an abnormality occurs. It is provided.

The TIP and TIP explosive cutoff valve will be described with reference to FIGS. 3 and 4.

FIG. 1 is a layout view showing the entire TIP drive system. A pressure vessel 2 is installed in the reactor containment vessel 1, and a plurality of local output region neutron flux detector assemblies 3 are attached to the pressure vessel 2 at predetermined positions.

The TIP drive system comprises a calibration conduit 4 and TI installed in the local output region neutron flux detector assembly 3.
A P indexing device 5, a TIP ball valve 6, a TIP explosive cutoff valve 7, a TIP shielding container 8, a TIP drive device 9 and a TIP guide tube 10 which connects these devices and forms a guide passage for a TIP detector cable.

The TIP explosive cutoff valve 7 shown in FIG.
As shown in FIG. 3, a TIP guide pipe 19 penetrates the valve body 11, and a TIP detector cable 20 passes through the TIP guide pipe 19. In the valve body 11, the TIP
A cutter 12 is provided which is capable of advancing in a direction perpendicular to the guide tube 19 and cutting the TIP guide tube 19 together with the TIP detector cable 20. The cutter 12 has a cylindrical body and a wedge-shaped blade, and the explosive contained in a power cartridge 13 installed opposite to the rear end of the body is plugged from a control panel (not shown) to a plug 14 An electric current is applied to the blade to explode, and a propulsive force is applied to the blade to move forward to cut the TIP guide tube 19 and the TIP detector cable 20, and the blade is embedded in the flat surface of the blade and the valve body 11. The packing 18 is in close contact and seals the cut surface,
Realizes isolation of the TIP drive system. In order to detect that the cutter 12 has moved forward to cut the TIP guide tube 19 and the TIP detector cable 20 and to seal the cut surface, when the cutter 12 reaches the position, the pin 16 is pushed and the position is detected. A detector 17 is provided, and the detection result is output from the plug 15 to a control panel (not shown).

The conventional power cartridge 13
Is a metal cartridge body 21 as shown in FIG.
An igniting charge 24 and an explosive charge 25 are housed in the insulating support 3
The ignition charge 24 covering the heating electrode 23 connected between the pin electrodes 22a and 22b supported by 1 is ignited by the heat generated by the heating electrode 23 to explode the explosive charge 25.

[0008] Such a conventional power cartridge 13
When the igniting charge 24 and the explosive charge 25 explode (combust), the conductive combustion residue 26 adheres to the inner wall surface 21a of the explosive storage chamber of the cartridge body 21 and the cartridge body 2
1, the insulation resistance between the pin electrodes 22a and 22b decreases,
A leakage current may flow from the energized pin electrodes 22a and 22b to the cartridge body 21.

However, the instrumentation system is provided with an earth leakage detection (alarm) means, and the mobile core instrumentation explosive disconnect valve 7 is provided.
However, there is a problem that the system is confused when the leakage detection means also operates when is activated.

Incidentally, Japanese Patent Laid-Open No. 5-220380 discloses a power cartridge of this type, but lacks consideration for leakage due to combustion residues.

[0011]

As described above, the conventional mobile type in-core instrumentation charge disconnection valve 7 is used in the power cartridge 1
There was a problem that the conductive combustion residue 26 generated by the explosive (combustion) of the explosive No. 3 caused electric leakage to confuse the system.

It is an object of the present invention to prevent electric leakage due to conductive combustion residue generated in the power cartridge of the mobile in-core instrumentation charge disconnection valve when the valve operates.

[0013]

DISCLOSURE OF THE INVENTION The present invention is directed to a movable in-core instrumentation detector cable by moving a cutter forward by energizing a heat generating electrode with explosive stored in a power cartridge mounted on a valve body to explode. In a movable core instrumentation charge disconnection valve adapted to cut the guide tube, the power cartridge interior wall of the power cartridge is covered with an electrically insulating layer, or between the power cartridge and the valve body Characterized by interposing an electrical insulation layer,
Alternatively, the body of the power cartridge is formed of an electrically insulating material.

With the above construction, the electrically insulating member is interposed between the electrode to be energized and the valve body, so that even if a conductive combustion residue is generated, electric leakage does not occur.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. The same components as those of the conventional mobile in-core instrumentation charge disconnection valve described above are designated by the same reference numerals, or are omitted from the drawings and duplicate description is omitted.

In the first embodiment, the explosive storage chamber inner wall surface 21a of the cartridge body 21 of the power cartridge 13 is covered with a cylindrical insulating sleeve 27, and explosives (combustion) of explosives 24, 25 cause conductive combustion. Even if a residue is generated, an electric path due to the combustion residue is prevented from being formed between the pin electrodes 22a and 22b.

Nylon is suitable for the material of the insulating sleeve 27, and by forming it to a thickness of 1 mm or more, it was possible to maintain an insulating resistance of 0.2 MΩ or more even after the operation.

A second embodiment of the present invention will be described with reference to FIG. The same components as those of the conventional mobile in-core instrumentation charge disconnection valve described above are designated by the same reference numerals, or are omitted from the drawings and duplicate description is omitted.

In the second embodiment, a synthetic resin type insulating member 28 is interposed on the mounting surface of the power cartridge 13 with respect to the valve body 11 of the movable in-core instrumentation charge cutting valve 7.
The valve body 11 and the power cartridge 13 are electrically disconnected from each other. Therefore, even if the cartridge body and the pin electrode are electrically connected by the conductive combustion residue, the pin electrode does not leak to the valve body, and the problem of leakage due to the conductivity of the combustion residue is eliminated.

A leakage current due to the combustion residue flows through the conductive cartridge body of the power cartridge 13. Therefore, even if the cartridge body is made of an insulating material, the occurrence of electric leakage can be prevented.

[0021]

INDUSTRIAL APPLICABILITY As described above, the movable core instrumentation explosive cutoff valve according to the present invention may cause electric leakage due to conductive combustion residue generated by the explosion (combustion) of the explosive contained in the power cartridge. Absent.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional side view of a power cartridge in a TIP explosive cutoff valve showing a first embodiment of the present invention.

FIG. 2 is a vertical sectional side view of a TIP explosive cutoff valve according to a second embodiment of the present invention.

FIG. 3 is a layout diagram showing an entire TIP drive system in a conventional boiling water reactor.

FIG. 4 is a vertical sectional side view of a conventional TIP explosive cutoff valve.

FIG. 5 is a vertical sectional side view of a power cartridge in a conventional TIP explosive cutoff valve.

[Explanation of symbols]

 21 valve body 21a explosive storage chamber inner wall surface 22a, 22b pin electrode 23 heat generating electrode 24 ignition charge 25 explosive charge 27 insulating sleeve

Front Page Continuation (72) Inventor Shinya Omori 3-1-1, Saiwaicho, Hitachi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor Hideyo Saito 3-1-1, Saiwaicho, Hitachi, Ibaraki Stock company Hitachi Ltd. Hitachi factory (72) Inventor Masafumi Watanabe 21 21 Matoba Shinmachi, Kawagoe-shi, Saitama Prefecture 2 NOF Giken Kogyo Co., Ltd. Kawagoe plant (72) Inventor Nao Kazama 21 Shinmachi, Kawagoe, Saitama Prefecture Address 2 NIPPON GIKEN CORPORATION Kawagoe Factory

Claims (4)

[Claims] 1. A cutter is advanced by energizing a pyrotechnic electrode stored in a power cartridge mounted on a valve body to generate heat to explode the cutter, thereby cutting the movable in-core instrumentation detector cable and the guide tube. A mobile in-core instrumented explosive shutoff valve, characterized in that the wall surface of the power cartridge's explosive storage chamber is covered with an electrically insulating layer. 2. The mobile in-core instrumentation charge cutoff valve according to claim 1, wherein the electrical insulation layer is formed of nylon. 3. The movable in-core instrumentation detector cable and the guide tube are cut by advancing the cutter by energizing and exploding the heat generating electrode with the explosive stored in the power cartridge mounted on the valve body. A mobile in-core metered-explosive cutoff valve, wherein an electrically insulating layer is interposed between the power cartridge and the valve body. 4. A cutter is advanced by energizing a heat generating electrode with explosive stored in a power cartridge mounted on a valve body to explode, thereby cutting a movable in-core instrumentation detector cable and a guide tube. A mobile in-core metered explosive cutoff valve, characterized in that the body of the power cartridge is formed of an electrically insulating material.