JPS6310558Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention is used for a nuclear reactor that uses liquid metal sodium as a primary coolant, for example, and is used in a fuel exchanger that is drawn into the reactor vessel, a television camera for inside the reactor inspection, and a reactor. This invention relates to a shaft sealing device for equipment inserted into a furnace, which is used for measuring various physical quantities in a furnace.

First, the basic structure of this type of shaft sealing device will be explained with reference to FIG. In the figure, 1 is the reactor core, 2 is the upper shield plug of the reactor vessel housing the reactor core, 3, 4
are liquid metal sodium as the primary coolant and cover gas, respectively, sealed in the reactor vessel. The fuel exchanger 5 has a flexible main body and is drawn into the furnace from outside the furnace through the through hole 6 of the plug 2 and the door valve 7 installed on the top surface of the plug.
It is lifted and lowered by the lift drive mechanism 8 of the fuel exchanger to load fuel into the reactor core 1 and to extract fuel from the core. On the other hand, the cover gas inside the furnace contains highly radioactive sodium vapor, and in order to prevent this cover gas from leaking out of the furnace, a shaft sealing device 9 for the fuel exchanger 5 is installed above the door valve 7. There is. This shaft sealing device 9 is a fuel exchanger 1
a shaft seal housing 10 that surrounds the main body of the shaft seal housing, and a shaft seal packing 1 for preventing cover gas leakage that constitutes a furnace pressure boundary installed inside the shaft seal housing.
In addition to 1, when the fuel exchanger 1 is pulled out of the furnace, the sodium adhering to the surface of the part inserted into the furnace is taken out of the furnace as it is, or it adheres to the shaft sealing packing 11, reducing its sealing performance. To prevent this, a primary coolant sodium cleaning member 12 is installed in the shaft seal housing 10 in line with the shaft seal packing 11. This sodium cleaning member 12 is made as a braided body or a brush body of heat-resistant and corrosion-resistant metal wire, and is installed so as to be in direct contact with the outer surface of the main body of the fuel exchanger. Therefore, when the fuel exchanger is pulled out of the furnace, the sodium adhering to the outer surface of the main body is scraped off and removed by the cleaning member 12 before the shaft seal packing 11.

In the conventional shaft seal device, the primary coolant cleaning member 12 described above is fixedly attached to the shaft seal housing 10, as shown in FIG. For this reason, when the fuel exchanger 5 is moved up and down, if the fuel exchanger 5 is slightly eccentric due to a slight misalignment between the fuel exchange position of the core and the fuel exchanger, it may hit unevenly with the cleaning member 12. An abnormal increase in sliding resistance occurs. As a result, there is a risk that problems such as a decrease in the sodium removal performance and an obstruction to smooth lifting and lowering operations of the fuel exchanger may develop.

This idea was developed in consideration of the above points, and its purpose is to eliminate the drawbacks of the conventional equipment, and to prevent uneven contact between the primary coolant cleaning member and the primary coolant cleaning member even if the equipment inserted into the furnace is slightly eccentric. To provide a shaft sealing device for equipment inserted into a furnace, which can always maintain a good primary coolant cleaning function without fear of abnormal increase in sliding resistance.

According to this invention, this object is achieved by supporting the housing case within the shaft seal housing while maintaining a loose fitting gap between the outer periphery of the housing case housing the primary coolant cleaning member and the shaft seal housing. be done.

This invention will be explained below based on illustrated embodiments.

In FIG. 3, the cleaning member 12 is not fixed to the shaft seal housing 10 as it is, but is housed in a housing case 13, and the housing case 13 is loosely fitted and supported on the shaft seal housing 10 so as to be movable in the radial direction. ing. That is, a loose fitting gap g is provided in advance between the outer periphery of the accommodation case 13 and the shaft seal housing 10, and within this gap g, the fuel exchanger 5
Even if the cleaning member 12 is slightly eccentric in the direction of the arrow, the cleaning member 12 can eccentrically move within the shaft seal housing 10 following the fuel exchanger 5. Therefore, even if the fuel exchanger 5 is slightly eccentric, uneven contact with the cleaning member 12 or abnormal increase in sliding resistance does not occur, and the cleaning member always stably contacts the outer surface of the fuel exchanger 5. A good cleaning function of the primary coolant can be maintained.

Next, a more specific example based on Fig. 3 is shown in Fig. 4.
As shown in the figure. In the figure, reference numeral 14 is a fixing bolt for the shaft seal housing 10, 15 is a packing holder, 16 is a tightening bolt for the packing holder, 17 is an assembly bolt for the housing case 13, 18 is a flange for supporting the housing case, 1
9 is a fixing bolt of the flange, and 20 is a partition plate inserted between each cleaning member segment.

Although the illustrated embodiment has been described with reference to a fuel exchanger in a liquid metal sodium cooled nuclear reactor, the present invention can be similarly applied to various types of equipment inserted into a reactor other than a fuel exchanger. Furthermore, if the primary coolant is water other than liquid metal, it goes without saying that the same method as in the illustrated embodiment can be carried out by simply changing the cleaning member to felt, for example.

[Brief explanation of the drawing]

Figure 1 is an overall schematic configuration diagram showing the state in which the fuel exchanger, which is the equipment inserted into the reactor, is inserted into the reactor.
The figure is a cross-sectional view of the configuration of a conventional shaft sealing device, Figure 3 is a cross-sectional view of the basic configuration of an embodiment of this invention, and Figure 4 is a cross-sectional view showing the structure of a more specific embodiment based on Figure 3. It is. 2... Furnace vessel plug, 3... Primary coolant, 4
... Cover gas, 5 ... Fuel exchanger as equipment inserted into the furnace, 9 ... Shaft seal device, 10 ... Shaft seal housing, 11 ... Shaft seal packing, 12 ... Primary coolant cleaning member, 13 ... Containment case, g...play space.

Claims (1)

[Scope of utility model registration request] A shaft seal gasket for preventing furnace cover gas leakage is installed on the inner periphery of the shaft seal housing that surrounds the outer periphery of the penetrating end of the equipment inserted into the furnace that penetrates the plug of the furnace vessel and is drawn into the furnace. In the shaft sealing device of equipment inserted into the reactor, which is equipped with a primary coolant cleaning member that scrapes off the primary coolant adhering to the outer surface of the part inserted into the reactor when the equipment is pulled out of the reactor, primary cooling is performed. The accommodation case is supported in the shaft seal housing with a loose fitting gap maintained in advance between the outer periphery of the storage case that accommodates the material cleaning member and the shaft seal housing, and the housing case is supported against the eccentricity of the equipment inserted into the furnace. A shaft sealing device for equipment inserted into a nuclear reactor, characterized in that a case can be moved in a radial direction.