JPH11337691A - Vacuum drying device for spent nuclear fuel containment vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum drying device of containment vessel capable of facilitating the regeneration work of cold trap. SOLUTION: This device 1 is constituted of a vacuum pump 12 for sucking the air containing steam in a containing vessel 2 for containing spent nuclear fuel through a sucking tube 11, a cold trap 13 installed on the way of the sucking tube 11 and for removing water and brine from an evaporator 21 of an ammonia absorbing type heat pump device 14 is supplied to heat conduction pipes 16 which is provided inside a vessel body 15 of the cold trap 13. In addition, hot water having passed an absorber 22 and a condenser 24 in the heat pump device 14 is supplied during removing of ice in the cold trap 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum drying apparatus for a container for storing spent nuclear fuel.

[0002]

2. Description of the Related Art Normally, spent nuclear fuel generated in a nuclear facility such as a nuclear power plant is transported (or stored) in a specially manufactured container for storing spent nuclear fuel.

In this storage container, water is filled, and spent nuclear fuel is immersed in the water to cool and shield radiation. By the way, when transported immersed in water,
Because of the need to treat radioactivity, a method has recently been proposed in which spent nuclear fuel is stored without being immersed in water, that is, dry.

[0004] As described above, as a method for drying the spent nuclear fuel in the storage container, a method in which the pressure in the storage container is reduced by using a vacuum device to evaporate water is considered. When the water vapor in the storage container is sucked by the vacuum device together with the air, a cold trap for removing the water vapor is required in the suction pipe.

[0005] As the cold trap, a cold trap in which a cooling material (for example, a product in which dry ice is immersed in alcohol and cooled to about -70 ° C) is disposed in a container body is used.

Therefore, when the air in the storage container is sucked into the container body, it is cooled here, and the moisture contained in the air is frozen and removed. When the frozen ice accumulates to some extent in the container main body, after the coolant is taken out of the container main body, the heating material is inserted and the ice collected in the container main body is melted and taken out as water. Had been.

[0007]

In the above-mentioned cold trap, when ice generated in the container body is removed,
After taking out the coolant from the container body, the heating material is inserted to melt the ice, so that there is a problem that the operation of regenerating the cold trap is very troublesome.

Accordingly, an object of the present invention is to provide a vacuum drying apparatus for a storage container that can easily perform a cold trap regeneration operation.

[0009]

In order to solve the above-mentioned problems, a vacuum drying apparatus for a container for storing spent nuclear fuel according to the present invention comprises a suction pipe for sucking air in a container for storing spent nuclear fuel. And a cold trap that is interposed in the middle of this suction pipe to remove moisture, and a heat transfer section provided in the container body of the cold trap has an absorption type. The cooling fluid is supplied from the evaporator of the heat source device, and when the ice is removed by the cold trap, at least the heating fluid passing through the condenser in the absorption heat source device or the heat storage on the absorption heat source device side The heating fluid stored in the tank is supplied.

[0010] According to the above configuration, the cooling fluid and the heating fluid generated on the absorption heat source device side are used as the heat source of the cold trap for removing the moisture contained in the air in the storage container. The regeneration operation in the trap can be performed simply by switching the supplied fluid.

In another aspect of the present invention, there is provided a vacuum drying apparatus for a spent nuclear fuel storage container, the vacuum pump for sucking air in the storage container for storing the spent nuclear fuel through a suction pipe, and a vacuum pump. A cold trap having a cooling chamber which is interposed in the middle of the suction pipe and guides and cools the air in the storage container, and which is generated on the absorption heat source device side above the cooling chamber of the cold trap. And a return pipe for returning the cooling fluid accumulated in the lower part of the cooling chamber to the absorption heat source device side.

[0012] According to the above configuration, as a cold trap, the cooling fluid from the absorption heat source device side can be brought into direct contact with the air, so that there is no particular need for a regeneration operation for removing frozen ice.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vacuum drying apparatus for a container for storing spent nuclear fuel according to a first embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 1 denotes a vacuum drying apparatus for drying the inside of a storage container 2 for transporting spent nuclear fuel,
A vacuum pump 12 for suctioning air containing steam (hereinafter simply referred to as air) in the storage container 2 through a suction pipe (suction pipe) 11; And a cold trap 13 for freezing and removing moisture contained in the water, and an absorption heat source device such as an ammonia absorption heat pump as a heat source device for supplying a cooling fluid and a heating fluid to the cold trap 13. Apparatus 14 is used.

The cold trap 13 has a cooling chamber 15a through which air sucked by the vacuum pump 12 can pass.
A heat transfer tube (heat transfer portion) 16 is arranged in a container body 15 having

The heat pump device 14 is mainly composed of an evaporator 21 for evaporating the ammonia liquid, an absorber 22 for guiding the ammonia vapor generated by the evaporator 21 and absorbing it into water, , A regenerator 23 that guides and heats a concentrated aqueous ammonia solution having a high concentration to separate ammonia, a condenser 24 that guides and condenses the ammonia vapor separated by the regenerator 23, The heat storage tank 25 stores hot water (heating fluid) whose temperature has been raised to about 50 ° C. through the heat transfer tubes 22a, 24a of the condenser 24. In addition, as a heat source of the regenerator 23, waste steam or the like is used.

The heat transfer tube 21a in the evaporator 21
And the heat transfer pipe 16 in the cold trap 13 are connected by a cooling fluid circulation pipe 31 for circulating brine (cooling fluid), and at the middle of an inlet pipe section 31a and an outlet pipe section 31b of the circulation pipe, respectively. Three-way switching valve 3
2, 33 are provided.

A heating fluid circulation pipe 34 is connected between the three-way switching valves 32 and 33 and the heat storage tank 25, and hot water of about 50 ° C. stored in the heat storage tank 25 is stored in the cold trap 13. Is circulated and supplied to the heat transfer tube 16.

Therefore, when the spent nuclear fuel is transported dry in the storage container 2, the spent nuclear fuel is first stored in the storage container 2, and then the vacuum pump 12 is driven to drive the suction pipe 11. The air containing the vapor in the storage container 2 is sucked. The air sucked by the vacuum pump 12 is supplied to the cooling chamber 1 of the container body 15 of the cold trap 13.
5a, where it flows through the heat transfer tube 16 -30 to-
The water (vapor) in the air is frozen and removed by cooling with brine of about 50 ° C. (specifically, ethylene glycol or the like is used).

By the way, it is necessary to take out ice when a certain amount of ice has accumulated in the cooling chamber 15a of the container body 15. In this case, the two-way switching valves 32 and 33 are switched, and the heating fluid circulating pipe 34 is used to heat the heat storage tank 25. Is flowed into the heat transfer tube 16. Therefore, the cooling chamber 15a
The ice frozen inside is melted and discharged from an outlet (not shown) of the container body 15.

In order to remove the ice collected in the cold trap 13, the three-way switching valves 32, 33 are simply used.
Only by operating the cold trap 13, the hot water in the heat storage tank 25 can be guided to the cold trap 13 to melt the ice, so that the cold trap 13 can be regenerated very easily.

Next, a vacuum drying apparatus for a container for storing spent nuclear fuel according to a second embodiment of the present invention will be described with reference to FIG. In the cold trap according to the first embodiment, as the heat source of the cold trap, the cooling fluid and the heating fluid from the absorption type heat pump device are caused to flow through the heat transfer tube, so that heat is indirectly exchanged with air. In the second embodiment, the cooling fluid from the absorption heat pump device is brought into direct contact with the air from the storage container.

That is, as shown in FIG. 2, a vacuum drying device 41 according to the second embodiment comprises a storage container 42.
A vacuum pump 52 for sucking air containing steam through a suction pipe (suction pipe) 51, and freezing and removing moisture contained in the middle of the suction pipe 51 by cooling the air. An absorption heat source device, for example, an ammonia absorption heat pump device 54 is used as a heat source device for supplying brine (cooling fluid) to the cold trap 53.

The cold trap 53 is provided with a container body 55 having a cooling chamber 55a for guiding air from the storage container 42, and is inserted and arranged above the cooling chamber 55a of the container body 55 to cool the brine. An injection pipe 56 for injecting the air into the cooling chamber 55a, and an outlet 57 for drawing out the brine accumulated in the lower portion of the cooling chamber 55a, and the brine is provided between the cooling chamber 55a and the heat transfer pipe 61a of the evaporator 61. And a cooling fluid return pipe 59 for returning the brine in the cooling chamber 55a to the evaporator 61 side. A solution pump 60 is provided in the middle of the cooling fluid return pipe 59.

Therefore, the air in the storage container 42 is sucked toward the cold trap 53 by the vacuum pump 52, but in the cooling chamber 55 a of the container body 55, the air injected from the injection pipe 56 is −30 to −50. ℃ brine (Specifically, ethylene glycol is used)
And the moisture in the air is frozen and removed. The frozen ice is directly mixed with the brine and discharged to the outside.

As described above, the moisture (steam) contained in the air is frozen by the brine injected from the injection pipe 56 and is discharged to the outside together with the brine. As in the case of the embodiment, the regeneration operation of the cold trap can be easily performed.

In the first embodiment, the hot water generated by the heat pump device is temporarily stored in the heat storage tank. However, the hot water directly heated by the absorber and the condenser is required. Only at times, it can be supplied to the cold trap side.

In the second embodiment,
Although the brine supplied into the cold trap has been described as being cooled in the evaporator, for example, as described in the first embodiment, the brine cooled in the evaporator is
Once stored in a tank (if the brine is water, an ice storage tank is used), another brine can be circulated between the tank and the cold trap.

[0029]

As described above, according to the configuration of the vacuum drying apparatus of the present invention, as the heat source of the cold trap for removing the moisture contained in the air in the storage container, the cooling fluid generated on the absorption heat source device side and Since the heating fluid was used, the regeneration operation in the cold trap was simply
This can be performed simply by switching the fluid to be supplied, and thus does not require a cumbersome operation of removing the coolant from the cold trap and then adding the heating material as in the related art.

Further, according to another configuration of the vacuum drying apparatus of the present invention, the cooling fluid from the absorption heat source device side is brought into direct contact with air as a cold trap, so that the frozen ice is taken out. No special work is required.

That is, according to the configuration of each of the vacuum drying apparatuses, the operation of regenerating the cold trap can be performed very easily.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a vacuum drying device for a storage container according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a vacuum drying device for a storage container according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum drying device 2 Storage container 11 Suction pipe 12 Vacuum pump 13 Cold trap 14 Heat pump device 15 Container main body 16 Heat transfer tube 24 Condenser 25 Heat storage tank 31 Cooling fluid circulation piping 32, 33 Three-way switching valve 34 Heating fluid circulation piping 41 Vacuum Drying device 42 Storage container 51 Suction pipe 52 Vacuum pump 53 Cold trap 54 Heat pump device 55 Container body 56 Injection pipe 58 Cooling fluid supply pipe 59 Cooling fluid return pipe 61 Evaporator

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Otsuka 1-7-89, Minamikohoku, Suminoe-ku, Osaka-shi, Osaka Inside Hitachi Zosen Corporation (72) Inventor Yoshinobu Takagi 1-chome, Minamikohoku, Suminoe-ku, Osaka-shi, Osaka 7-89 Hitachi Zosen Corporation (72) Inventor Katsuhiko Tsuji 1-7-89 Minami Kohoku, Suminoe-ku, Osaka-shi, Osaka Inside Hitachi Zosen Corporation

Claims (2)

[Claims] 1. A vacuum pump for sucking air in a storage container for storing spent nuclear fuel through a suction pipe, and a cold trap interposed in the suction pipe for removing moisture. And to supply the cooling fluid from the evaporator of the absorption heat source device to the heat transfer section provided in the container body of the cold trap, and when removing the ice in the cold trap, Vacuum drying of a container for storing spent nuclear fuel, characterized in that a heating fluid passed through at least the inside of the condenser in the absorption heat source device or a heating fluid stored in the heat storage tank on the absorption heat source device side is supplied. apparatus. 2. A vacuum pump for sucking air in a storage container for storing spent nuclear fuel through a suction pipe, and an air in the storage container inserted in the middle of the suction pipe. And a cold trap having a cooling chamber for guiding and cooling, and an injection pipe for injecting a cooling fluid generated on the absorption heat source device side is arranged above the cooling chamber of the cold trap, and a lower part of the cooling chamber A return pipe for returning the cooling fluid accumulated in the tank to the absorption heat source device side, wherein the vacuum drying device for the container for storing spent nuclear fuel is provided.