JPS634678B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a cooling system for inspection equipment in a fast breeder reactor, particularly for inlet piping inspection equipment such as television cameras and electronic equipment used in reactor vessel ISI (in-service inspection) equipment. This relates to a cooling device for cooling (ITV).

In a fast breeder reactor, equipment that is particularly important for safety needs to be inspected as necessary during use, but the area around the reactor vessel of a fast breeder reactor requires nitrogen gas not only during reactor operation but also when the reactor is shut down. The harsh atmosphere, such as gas atmosphere, high temperature, and high radiation dose rate, makes it impossible for workers to approach, and the ISI
All of the testing equipment used is remotely controlled equipment. Most of these inspection equipment are heat resistant, but ITV (inlet piping inspection equipment) is the only one that cannot be made heat resistant, so it must be kept cooled to a working temperature of -10℃ to +50℃. In an inspection space where the atmosphere is around 250°C, it is extremely difficult to cool and maintain the temperature to the operating temperature.

That is, as shown in Fig. 1, the ITV cooling system in the conventional fast breeder reactor is such that the ITV is suspended by a chain 2 and moves in and out of the inspection space.
3, a large storage tank 4 containing liquid nitrogen is fixedly arranged in the room temperature atmosphere on the operation floor 5, and a flexible hose 6 is connected between the storage tank 4 and the ITV 3, and the liquid nitrogen in the storage tank is is guided through a flexible hose 6 to cool the ITV 3. However, in such a conventional cooling system, the length of the flexible hose 6 from the storage tank 4 to the ITV 3 is approximately 50 m, and the liquid nitrogen is heated by heat input along the way.
The cooling capacity for ITV3 is reduced, and as a result,
To maintain ITV3 within the operating temperature range of -10°C to +50°C, approximately 400 kg/hr of nitrogen is required.
For this reason, the cooling equipment becomes larger and the consumption of liquid nitrogen increases, which is economically disadvantageous, and the nitrogen gas used for cooling is treated as waste gas, so the waste gas system of the nuclear power plant This causes problems such as an increase in size and difficulty in temperature control, and a solution to these problems is desired.

This invention was made in view of the above-mentioned circumstances, and it is possible to miniaturize the cooling device, reduce the consumption of liquid nitrogen, and downsize the waste gas system of a nuclear power plant. The object of the present invention is to provide a cooling device for inspection equipment in a fast breeder reactor that can be easily used.

In response to this purpose, the cooling device for testing equipment in a fast breeder reactor of the present invention includes a container capable of containing liquefied gas arranged near the testing equipment holder, and the container and the testing equipment holder being connected by flexible piping. , and is characterized in that the container can be moved into and out of the testing space together with the testing equipment holder.

The details of this invention will be explained below with reference to the drawings showing one embodiment.

In FIG. 2, 11 is a fast breeder reactor, and the fast breeder reactor 11 is equipped with a reactor vessel 12. The reactor vessel 12 is supported by a pedestal 13, and its upper end opening is closed by a shielding plug 14. A guard vessel 15 is provided outside the reactor vessel 12. Reactor vessel 12
The reactor coolant inlet pipe 16 extends from the guard vessel 15, and the ISI guide pipe 17 extends from the guard vessel 15, and the base end of the inlet pipe 16 extends from the ISI guide pipe 17.
It is contained in the proximal end of the
An inspection space 18 is configured for loading ITV (inspection equipment for reactor inlet piping). ITV19 is ITV
It is held in the holder 25 and inserted into the inspection space 18 to inspect the properties of the reactor inlet piping 16.
The output of the ITV 19 is sent via a cable 23 to, for example, a monitor television 22 for display.

As shown in FIG. 3, the cooling device 24 of the present invention includes an ITV holder 25 that holds the ITV 19, a flexible tube 26, and a cold converter 27.

The ITV holder 25 has a cylindrical shape with an opening 28 at one end, and houses the ITV 19 inside. A passage 30 is formed between the wall portion 29 of the ITV holder 25 and the ITV 19 through which nitrogen gas can flow. Further, the wall portion 29 has a heat insulating structure to prevent heat from entering from an external high temperature atmosphere. As a heat insulating structure, the wall portion 29 may be made of a heat insulating material such as pearlite or lock fine, or the inside of the wall portion 29 may be evacuated. Further, a super insulation structure may be adopted. Super insulation generally refers to an insulation method that reduces radiation, convection, and conduction by layering Al foil and glass wool on top of each other and creating a vacuum in the space formed.

The cold converter 27 is a container with a double structure consisting of an inner tank 31 and an outer tank 32 having an airtight structure, and can store liquid nitrogen in the inner tank 31. Furthermore, a heater 33 is provided within the inner tank 31. This heater 33 can vaporize liquid nitrogen. Inner tank 31
A heat insulating structure is provided between the outer tank 32 and the outer tank 32. As its heat insulating structure, a structure similar to that adopted in the above-described ITV holder 25 can be adopted. Further, the cold converter 27 is provided with a liquid level gauge 34 and a liquid nitrogen supply port 35 is attached.

Inner tank 31 of cold converter 27 and ITV
It communicates with the passage 30 of the holder 25 via a flexible tube 26. The joint between the cold converter 27 and the flexible tube 26 has a heat insulating joint structure, and can be installed and removed.
A heat insulating rotary joint is connected to the ITV holder 25 and can be attached and removed. The flexible tube 26 is composed of a flexible inner tube and an outer tube, and a spacer is provided to ensure a distance between the inner tube and the outer tube. The gap 12 between the outer tube and the inner tube has a heat insulating structure, and as such a heat insulating structure, a structure similar to that adopted in the ITV holder 25 can be adopted. Furthermore, a heater 36 is provided within the flexible tube 26. The heater 36 controls the temperature of the nitrogen gas vaporized within the cold converter 27.

The cooling device 24 may be suspended from the tip of the chain 37 and positioned within the inspection space 18 . The chain 37 is wound up or unwound by the drive device 38, whereby the cooling device 24 moves up and down into and out of the ISI guide tube 17 while holding the ITV in the ITV holder 25.

Due to the cooling device 24 configured as described above,
Cooling of the ITV 19 is performed as follows.

First, wind up the chain 37 and connect the cooling device 2.
4 to the position shown by the chain line 24' in FIG.
Liquid nitrogen is supplied from the liquid nitrogen storage tank 39 to the cold converter 27. Next, the chain 37 is unwound and inserted into the inspection space 18 together with the cooling device 24 into the ITV 19, and an in-service inspection (ISI) is performed. The liquid nitrogen in the cold converter 27 is heated by heat input from the surroundings and the heater 33.
After being heated and vaporized by the flexible tube 26, it reaches the ITV holder 25, and
It flows around the ITV 19 to cool the ITV 19, and then flows out from the open end 28. The liquid nitrogen in the cold converter 27 is vaporized to some extent due to the influence of the ambient temperature of 240°C, for example due to heat intrusion through super insulation, and the liquid nitrogen is transferred to the ITV.
The holder 25 is cooled, but the insufficient amount is heated by the heater 33, the supply amount is controlled, and if necessary, the heater 36 is also used to heat the holder 25. A decrease in liquid nitrogen in the cold converter 27 is detected by a liquid level gauge 34, and the liquid nitrogen is replenished by pulling it up to the position shown by the chain line 24'.

In this way, in the cooling device for inspection equipment in a fast breeder reactor of the present invention, the cold converter 27 is inserted into the ISI guide tube 17, so the cold converter 27 and the ITV holder 25 are positioned close to each other. This allows the flexible tube 26 connecting the two to be shortened, thereby reducing heat input along the way, and maintaining a high cooling capacity for the ITV 19. Therefore, the amount of liquid nitrogen required to maintain the ITV 19 at a predetermined operating temperature (-10°C to +50°C) is small. According to experiments, the amount of liquid nitrogen required for conventional cooling equipment is approximately 400 kg/kg.
hr, whereas the cooling device of this invention has a
It has become clear that 0.8Kg/hr is sufficient. As a result of using less liquid nitrogen, it is economically advantageous, and the apparatus can be downsized, controllability can be improved, and the amount of radioactive waste gas can be reduced.

The above explanation is about an example in which ITV is used as the inspection device and liquid nitrogen is used as the cooling fluid, but it can be applied to electronic devices other than ITV as the inspection device. Cooling fluids other than liquid nitrogen may also be used. In addition, the inspection target is not limited to the reactor inlet piping; therefore,
Of course, the place where the cooling device is installed is not limited to the place surrounded by the guard cell, and it can be used in other high-temperature atmospheres, and
It can also be used in an ambient temperature range of about 350°C or higher.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing a cooling device for inspection equipment in a conventional fast breeder reactor, and FIG. 2 is a configuration diagram showing a state in which a cooling device for inspection equipment according to an embodiment of the present invention is incorporated into a fast breeder reactor. The explanatory diagram and FIG. 3 are configuration explanatory diagrams showing a cooling device for inspection equipment according to an embodiment of the present invention. 12... Reactor vessel, 15... Guard vessel, 17... ISI guide tube, 19... ITV, 24...
...Cooling device, 25...ITV holder, 26...
Flexible tube, 27...cold converter.

Claims (1)

[Claims] 1. A container capable of containing liquefied gas is disposed near a testing equipment holder, the container and the testing equipment holder are connected by flexible piping, and the container is tested together with the testing equipment holder. 1. A cooling device for inspection equipment in a fast breeder reactor, characterized in that it is configured to be able to enter and exit a space for use. 2. An inspection device for a fast breeder reactor according to claim 1, characterized in that a heater capable of imparting heat to the liquefied gas is disposed inside at least one of the container and the flexible pipe. Cooling system. 3. Cooling of inspection equipment in a fast breeder reactor according to claim 1 or 2, wherein at least one of the container, the flexible pipe, and the inspection equipment holder has a heat-insulating structure. Device.