Method for sealing core wire of measurement control cable on containment side of nuclear power station

Abstract

The invention relates to the technical field of nuclear power plant containment integral test, in particular to a nuclear power plant containment side measurement control cable core wire sealing method. The method comprises the following steps: S1, carrying out compatibility analysis on a fireproof sealant and a sealing contact item; s2, selecting a fireproof sealant of which the compatibility meets the requirement; and S3, filling the fireproof sealant among the core wires of the measurement control cable. The sealing method is suitable for sealing between the containment side measurement control cable core wires under the condition that no electrical penetration assembly is designed on the containment boundary of a nuclear power plant, and the sealing effect of blocking gas leakage between the core wires during the containment whole test pressurizing period after the measurement control cable is terminated is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear power plant containment integral test, and in particular to a method for sealing a core wire of a measuring control cable at a containment side of a nuclear power plant. Background Art

[0002] Electrical penetrations are special electrical devices installed on the reactor containment wall for cables to pass through the containment. Under normal and various accident conditions, including earthquakes and loss of coolant accidents, electrical penetrations should be able to ensure the integrity of the reactor containment, prevent the leakage of radioactive materials, and maintain the continuity of electricity and signals inside and outside the containment.

[0003] During the construction of a certain unit in China, no technical requirements were specifically set for the termination of measurement and control cables on the containment side in the absence of electrical penetrations. After the measurement and control cables on the inside of the containment were terminated in the reactor building of the unit in accordance with the design technical documents, it was found that during the overall test pressurization of the containment, the measurement and control cables had leakage problems of varying degrees, which had a certain impact on the containment pressurization and pressure maintenance. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for sealing the core wires of a measuring control cable on the containment side of a nuclear power plant, which is suitable for sealing the core wires of a measuring control cable on the containment side when no electrical penetration is designed at the containment boundary of the nuclear power plant.

[0005] The present invention provides a method for sealing a core wire of a measurement control cable at a containment shell side of a nuclear power plant, comprising the following steps:

[0006] Step S1: Perform compatibility analysis on the fireproof sealant and the sealing contact items;

[0007] Step S2: Selecting a fireproof sealant with compatibility that meets the requirements;

[0008] Step S3: using the fireproof sealant to fill between the core wires of the measurement and control cable.

[0009] In a specific embodiment of the present invention, the sealed contact items include cables and heat shrink tubing.

[0010] In a specific embodiment of the present invention, step S3 specifically includes:

[0011] Step S3-1: stripping the cable sheath;

[0012] Step S3-2: Sleeve the heat shrink tubing onto the cable, and evenly fill it with fireproof sealant until the base of the core wires in contact with the cable sheath;

[0013] Step S3-3: shrinking the heat shrinkable tube;

[0014] Step S3-4: Apply sealant to the joint between the end of the heat shrink tubing and the core wire.

[0015] In a specific embodiment of the present invention, step S3-4 specifically includes:

[0016] Apply sealant to the joint between the end of the heat shrink tubing and the wire core, and ensure that the fireproof sealant is evenly filled between the wire cores;

[0017] Process the appearance of the fireproof sealant after filling and wrap and tighten it with insulating tape.

[0018] In a specific embodiment of the present invention, in the step S3-1, after the cable sheath is stripped off, the cable filler is removed.

[0019] Compared with the prior art, the method for sealing the core wires of the measuring and control cable on the containment side of a nuclear power plant of the present invention innovatively explores the use of fire-resistant sealants compatible with cables and heat shrink tubing to uniformly fill the gaps between the core wires before and after the cable termination, thereby achieving a sealing effect of blocking gas leakage between the core wires after the measurement and control cable is terminated during the overall test pressurization of the containment, when no electrical penetrations are designed at the boundary of the nuclear power plant containment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It shows the schematic diagram of stripping the cable sheath and reserving the appropriate length of the core according to the type of termination equipment;

[0021] Figure 2 Schematic diagram showing uniform filling of sealant between core wires;

[0022] Figure 3 It shows the schematic diagram of heat shrink tubing installation after the sealant between the core wires is filled;

[0023] Figure 4 Schematic diagram showing the application of sealant at the joint between the end of the heat shrink tubing and the wire core. DETAILED DESCRIPTION

[0024] In order to further understand the present invention, the embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the present invention.

[0025] An embodiment of the present invention discloses a method for sealing a core wire of a measurement and control cable at a containment side of a nuclear power plant, comprising the following steps:

[0026] Step S1: Perform compatibility analysis on the fireproof sealant and the sealing contact items;

[0027] The sealed contact items include cables and heat shrink tubing;

[0028] Step S2: Selecting a fireproof sealant with compatibility that meets the requirements;

[0029] Step S3: using the fireproof sealant to fill between the core wires of the measurement and control cable.

[0030] The step S3 is as follows: Figures 1 to 4 As shown, specifically including:

[0031] Step S3-1: stripping the cable sheath;

[0032] Specifically: Determine the cable stripping length according to the conditions of the terminated equipment;

[0033] Use a special electrician's tool to slowly peel off the cable sheath along the cable terminal direction and remove the cable outer skin;

[0034] Remove the cable filler;

[0035] Step S3-2: Sleeve the heat shrink tubing onto the cable, and evenly fill the fireproof sealant between the core wires where they contact the cable sheath, so that the core wires are evenly filled with the fireproof sealant;

[0036] Step S3-3: shrinking the heat shrinkable tube;

[0037] Step S3-4: Apply sealant to the joint between the end of the heat shrink tubing and the core wire;

[0038] Specifically: Apply sealant to the joint between the end of the heat shrink tubing and the wire core, and ensure that the fireproof sealant is evenly filled between the wire cores;

[0039] Process the appearance of the fireproof sealant after filling and wrap and tighten it with insulating tape.

[0040] The overall test pressure of the containment is used to test the cable core wires after filling with sealant.

[0041] After test verification, the fire-proof sealant in the cable fire-proof sealing material was used to evenly fill the cable core wires with fire-proof sealant before and after heat shrinkage. After the test pressure was evenly increased to 10.14kPa (the pressure during the containment test was ≥7.7kPa), the test cable was leak-checked and no gas leakage was found.

[0042] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0043] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for sealing the core wire of a measurement and control cable on the containment side of a nuclear power plant, characterized in that: The following steps are involved: Step S1: Perform compatibility analysis on the fireproof sealant and the sealing contact items; Step S2: Selecting a fireproof sealant with compatibility that meets the requirements; Step S3: using the fireproof sealant to fill between the core wires of the measurement and control cable.

2. The method for sealing the core wire of the measurement and control cable at the containment side of a nuclear power plant according to claim 1, characterized in that: The sealed contact items include cables and heat shrink tubing.

3. The method for sealing the core wire of the measurement and control cable at the containment side of a nuclear power plant according to claim 1, characterized in that: The step S3 specifically includes: Step S3-1: stripping the cable sheath; Step S3-2: Sleeve the heat shrink tubing onto the cable, and evenly fill it with fireproof sealant until the base of the core wires in contact with the cable sheath; Step S3-3: shrinking the heat shrinkable tube; Step S3-4: Apply sealant to the joint between the end of the heat shrink tubing and the core wire.

4. The method for sealing the core wire of the measurement and control cable at the containment side of a nuclear power plant according to claim 3, characterized in that: The step S3-4 specifically includes: Apply sealant to the joint between the end of the heat shrink tubing and the wire core, and ensure that the fireproof sealant is evenly filled between the wire cores; Process the appearance of the fireproof sealant after filling and wrap and tighten it with insulating tape.

5. The method for sealing the core wire of the measurement and control cable at the containment side of a nuclear power plant according to claim 3, characterized in that: In the step S3-1, after the cable sheath is stripped off, the cable filler is removed.

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