CN202034610U - Connecting device for cable joint in control rod system containment - Google Patents

Abstract

The utility model belongs to a connection device for a connection between a cable and a plug, in particular to a connection device for a cable joint in a containment shell of a control rod system. It includes the cable core wire, the solder joint of the cable core wire is filled with epoxy resin, the cable core wire and the joint are provided with a heat-shrinkable sleeve, and the cable core wire and the joint with the heat-shrinkable sleeve are installed on the cement wall In the shaft, the flange is fixed on the cement wall shaft by bolts. Its advantage is that by changing the joint structure and using a new sealing method, it can effectively prevent the entry of external water vapor through sealing and water vapor export, and has a good sealing and moisture reduction function, ensuring that the cable insulation is above the operating limit .

Description

Connection device for cable joints inside containment of control rod system

technical field

The utility model belongs to a connection device for a connection between a cable and a plug, in particular to a connection device for a cable joint in a containment shell of a control rod system.

Background technique

The VVER unit of Tianwan Nuclear Power Plant currently has 103 bundles of control rods, each of which is controlled by 103 drive mechanisms. The drive mechanism has the functions of lifting and inserting control rods and measuring the position of the control rods, that is, rod control and rod position. The drive mechanism is controlled by the upper layer. The cabinet provides power supply through 103 7-core cables (power cables) in the shell, and the upper control cabinet provides power for the rod position measurement sensor through 103 24-core cables (instrumentation and control cables) in the shell.

The driving mechanism is connected at the shaft of the reactor cement wall through its own cable and the power and instrument control cables inside the shell. The joints at the reactor shaft are CH-38-7A/30-1 (power cable connector), CH-38-24A/30 -1 (instrumentation and control cable connector). The cable joints and cable connections at the reactor shaft are shown in Figure 1. The cables and connectors are connected by welding, and epoxy resin is poured into the welding place to prevent external water vapor and air from entering, and to protect the welding point.

The joint is located in the shaft of the cement wall of the reactor. During the operation of the reactor, the temperature of the reactor shaft is high, the humidity is high, and there is radiation.

After a lifetime of operation, it was found during the overhaul that the insulation of some cables had been reduced, even lower than the operating limit (0.5MΩ). After analyzing the cause of the cable insulation drop, it was found that the root cause of the cable insulation drop was that the epoxy resin of the cable joint at the reactor shaft was cracked, causing condensation to seep into the contact of the joint. The reason for the condensed water is that the solder joints of the joints and the epoxy resin used for protection are in the holes of the cement wall shaft, and the water vapor in the core condenses in the holes, and the holes are horizontal and the joints are at relatively low points in the holes , so condensed water collects at the joints. As the epoxy cracked, condensation got inside the joint. This situation will affect the safe and stable operation of the unit. Based on the above situation, measures must be taken to prevent the insulation from falling below the operating limit.

Contents of the invention

The purpose of this utility model is to provide a connection device for cable joints in the control rod system containment that can prevent water vapor from entering the interior of the joints and ensure that the insulation value of the cable joints is above the operating limit.

The utility model is realized in the following way: the connecting device of the cable joint in the containment of the control rod system includes a cable core wire, and epoxy resin is poured into the welding spot of the joint of the cable core wire. The sleeve, the cable core wire and the joint with the heat-shrinkable sleeve are installed in the cement wall shaft, and the flange is fixed on the cement wall shaft by bolts.

The utility model has the advantages: by changing the structure of the joint and using a new sealing method, the entry of external water vapor is effectively prevented by means of sealing and water vapor export, and the function of good sealing and moisture reduction ensures that the cable insulation is in operation. above the limit. After actual use and verification, this scheme effectively improves the cable insulation. The cable whose insulation value is lower than 0.5MΩ in the original environment has reached more than 100MΩ after modification.

Description of drawings

Fig. 1 is a structural diagram of an existing joint connection device;

Fig. 2 is a schematic diagram of the connection device of the cable joint in the containment of the control rod system provided by the utility model.

In the figure, 1 bolt, 2 cement wall shaft, 3 epoxy resin, 4 cable core wire, 5 flange, 11 heat shrinkable sleeve.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment, the utility model is described in further detail.

As shown in Figure 2, the connection device of the cable joint in the containment of the control rod system includes a cable core wire 4, and epoxy resin 3 is poured at the welding point of the joint of the cable core wire 4, and the cable core wire 4 is connected to the outside of the joint. A heat-shrinkable sleeve 11 is sheathed, and the cable core wire 4 and the connector with the heat-shrinkable sleeve 11 are installed in the cement wall shaft 2 , and the flange 5 is fixed on the cement wall shaft 2 by bolts 1 .

The utility model remakes the cable joint, welds the cable and the joint according to the original welding method, pours epoxy resin into the welding spot, and wraps the heat-shrinkable sleeve on the outer layer for sealing.

Claims (1)

1. The connection device of the cable joint in the containment of the control rod system, which includes a cable core wire (4), and epoxy resin (3) is poured into the welding spot of the joint of the cable core wire (4), and is characterized in that: the cable core wire ( 4) A heat-shrinkable sleeve (11) is provided on the outside of the joint, and the cable core wire (4) with the heat-shrinkable sleeve (11) and the joint are installed in the shaft (2) of the cement wall, and the flange (5) passes through Bolt (1) is fixed on the cement wall shaft (2).

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