JPH11133187A - Disposal device for fast reactor metallic sodium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disposal device for fast reactor metallic sodium, capable of disposing safely and efficiently of a large amount of waste metallic sodium presumed to be produced from a fast reactor. SOLUTION: This disposal device is equipped with a metallic-sodium dealing means 1 for measuring a fixed amount for every disposal unit by the use of a dealing container 9 and a level gauge 13 provided in the dealing container 9, a metallic-sodium injection means 2 comprising a metallic-sodium injection nozzle and a gas-dispersion ring having inert-gas inflow ports disposed around the nozzle for nozzle clogging prevention, and a metallic-sodium reaction/ disposal means 25 comprising propeller-shaped blade plates provided in tiers by means of a blade support rod and a metallic-sodium cleaner 3 equipped with a plurality of vent holes for steam and hot water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for disposing of metallic sodium in a fast reactor for treating a large amount of metallic sodium used in a fast reactor in a chemically stable state for disposal.

[0002]

2. Description of the Related Art As is well known, in a fast reactor, metallic sodium is used as a coolant for a nuclear reactor. Sodium metal has the property of being a solid below about 100 ° C. but liquid above that temperature, and the sodium metal in both phases reacts violently with water to produce stable sodium hydroxide and hydrogen. In a fast reactor, metallic sodium adheres to a replacement device when the fuel in the reactor is exchanged, and therefore, when the device is maintained, the metal sodium is washed and removed. At the time of disposal of the fast reactor, a large amount of metallic sodium remains as waste after fuel is removed.

FIG. 8 is a schematic view showing a conventional alcohol cleaning method. The metal sodium adhering portion 82 of the fuel exchanger 81 to be cleaned is immersed in the alcohol 86 in the cleaning tank 85 via the exchanger door valve 83 and the cleaning tank door valve 84. After reacting with the water in the alcohol, the metallic sodium is discharged together with the alcohol as sodium alcoholate. It is adopted when it is necessary to slow down the reaction speed in consideration of the reuse of equipment.

FIG. 9 is a schematic diagram showing a conventional steam cleaning and water cleaning method. Steam 87 is applied to the fuel exchanger 81 to be cleaned, and after a certain amount of reaction is completed, hot water 88
To remove solids and the like.

[0005]

However, there is currently no known method for treating a large amount of sodium at the time of disposal of a fast reactor. As a treatment method, a method of sealing and storing at room temperature or a method of reacting with water to treat as chemically stable sodium hydroxide can be considered. However, long-term sealed storage of large amounts of metallic sodium requires strict control and involves a great deal of danger. On the other hand, a method in which metallic sodium is brought into the tank for each washing, such as the above-described alcohol or steam washing method, requires a huge amount of time for processing, and is not practical.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to dispose a sodium fast reactor waste disposal apparatus capable of safely and efficiently treating a large amount of waste metal sodium expected from a fast reactor. Is to provide.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there is provided a waste treatment apparatus for a fast reactor metal sodium, which chemically converts fast reactor metal sodium into sodium hydroxide and disposes the same according to the present invention. Metal sodium metering means for metering a fixed amount of metallic sodium in the reactor to be discarded by the liquid level meter provided for each processing unit and sending it out by the gas pressure transfer method, and preventing the metallic sodium injection nozzle and the nozzle from being clogged Injecting means for metallic sodium composed of a gas dispersing ring having an inert gas inflow port arranged around the nozzle to disperse the metal gas, and multi-stages provided via a blade supporting rod to finely scatter the metallic sodium to be dropped are provided. A steam and hot water mixing device for reacting propeller-shaped blades and metallic sodium adhering to the blades with steam and hot water. Is achieved by a metallic sodium to equip the through flow opening of the cleaning device comprises a reaction processing means configured metallic sodium.

In the above invention, it is effective that the metal sodium injection nozzle has a nozzle clogging removal port or that the propeller-shaped blades provided in multiple stages are arranged at a pitch of a predetermined angle from each other. The metal sodium metering means weighs out a fixed amount of metal sodium in the nuclear reactor to be discarded for each processing unit and sends it out. The metal sodium is sequentially reacted with steam and water in the reaction processing means described later.

The gas dispersing ring in the means for injecting metallic sodium has an inert gas inlet disposed around the metallic sodium injection nozzle, and inert gas supplied from the inert gas inlet is supplied with water vapor around the metallic sodium injection nozzle. To prevent the reaction between the injected metallic sodium and water vapor, thereby avoiding clogging of the metallic sodium injection nozzle.

[0010] The propeller-shaped blades in the means for reacting and treating metallic sodium finely scatter the dripped metallic sodium. A cleaning tool equipped with a plurality of flow openings for steam and hot water efficiently supplies steam and water to finely dispersed metallic sodium. The nozzle clogging removal port removes the nozzle clogging when an unexpected situation such as the blocking of the metal sodium injection nozzle occurs.

When the propeller-shaped blades provided in multiple stages are arranged at a pitch of a predetermined angle with respect to each other, the metallic sodium to be dropped is deposited on the blades of each stage on average, and the reaction between the metallic sodium and water vapor is performed. The area increases.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a system diagram showing a fast reactor metal sodium disposal apparatus according to the present invention. The liquid metallic sodium to be disposed of is received from the reactor into the dispensing means 1 in a reduced pressure state in advance. Means for measuring sodium metal 1
Accepts one processing volume. When the inside of the sodium metal metering means 1 is pressurized, the metal sodium is continuously injected into the injection means 2.
Sent to. The liquid metallic sodium 5 injected from the metallic sodium injecting means 2 falls into the cleaning tool 3 in the cleaning tank 4 in the metallic sodium reaction processing means 25,
It reacts gently with the steam 6 inside the washing tank 4 which is in advance in a steam atmosphere to produce a sodium hydroxide solution or a sodium hydroxide solid. In order to complete the reaction and to perform the next treatment, hot water 7 is injected and circulated into the washing tank 4 through a hot water circulation device, and then the hot water containing sodium hydroxide is drained to the waste liquid treatment tank. Storing completes a series of waste metal sodium treatments.

FIG. 2 is a sectional view showing the metering means of the fast reactor metal sodium waste disposal system. Heater coated heater 1
The quantity container 9 maintained at a predetermined temperature in 4 receives the metallic sodium from the metallic sodium supply pipe 10 and
And accept a prescribed amount that can safely process the metallic sodium 5. By pressurizing the inside of the measuring container 9, the metallic sodium is sent to the metallic sodium discharge pipe 11. The pressure gauge 12 detects the degree of pressurization at this time and the degree of negative pressure at the time of receiving waste metal sodium from the nuclear reactor into the metering vessel 9.

FIG. 3 is a sectional view showing an injection means of the fast reactor metal sodium disposal apparatus. Valve 8 above cleaning tank
The injection means installed above injects the metallic sodium sent from the quantity container 9 via the metallic sodium discharge pipe 11 from the metallic sodium injection nozzle 15 to the cleaning tool 3. An inert gas such as nitrogen gas is supplied from an inert gas injection nozzle 19 so as to prevent the metal sodium injection nozzle 15 from clogging with the water vapor 6 in the cleaning tank 4 in which the liquid metal sodium 5 to be dropped rises from the sodium dropping port 20. Metal sodium injection nozzle 1 through inert gas inlet 16
5 is blown down. Inert gas inlet 16
Are drilled on a gas dispersion ring 17 which covers the metal sodium injection nozzle 15 at a distance. If the metal sodium injection nozzle 15 is blocked, the nozzle clogging removal port 1
From FIG. 8, the metallic sodium in the injection nozzle can be removed. The injection means is maintained at a predetermined temperature by a heater 14 coated with a heat insulating material.

FIG. 4 is a sectional view of a crushing staircase showing the reaction processing means of the fast sodium metal waste disposal apparatus. FIG. 5 is a sectional view of the reaction processing means shown in FIG. FIG. 6 is a sectional view of the reaction processing means shown in FIG. FIG.
5 is a sectional view of the reaction processing means shown in FIG.

The wing plate 24 has a propeller shape, and has a structure in which metal sodium 5 dripped from the injection means 2 via the valve 8 is easily scattered with a twist. The slat 24 is a cleaning tool 3
Are provided in multiple stages via a slat support rod 22 supported by the fins. The blades 24 of each stage are fixed while being rotated by a predetermined angle with respect to each other, so that there is no gap when viewed in the direction of dropping of metallic sodium, and the dropped metallic sodium is uniformly applied to the blades 24 of each stage. Deposited on Since a large number of ventilation holes 23 are provided in the cleaning tool 3 in the vertical and circumferential directions, the steam 6 and the hot water 7 supplied from the cleaning tank 4 easily react with the metallic sodium 5.

[0017]

According to the present invention, there is provided the following effect. (1) A blade under a steam atmosphere finely disperses metallic sodium dropped from the metallic sodium injection means, but suppresses abrupt reaction and realizes stable and rapid metallic sodium treatment.

(2) The sodium hydroxide produced by the reaction between metallic sodium and steam is removed by a conventional hot water circulation. (3) Since an inert gas blow-down structure is adopted as the means for injecting metallic sodium and the means for distributing metallic sodium are provided, a stable batch treatment of metallic sodium can be performed without causing clogging of metallic sodium.

(4) Since the gas pressure transfer system is adopted as the means for distributing metallic sodium, an electromagnetic pump in which the pipe diameter generally used for sodium transfer is partially reduced is not required, and the diameter of the pipe when the electromagnetic pump is used is reduced. No metal sodium clogging due to fineness. (5) The present invention is applicable not only to a fast reactor metal sodium waste disposal apparatus but also to a case where stable treatment of general metallic sodium is required.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a fast reactor metal sodium disposal apparatus of the present invention.

FIG. 2 is a cross-sectional view showing a metering means of the fast reactor metal sodium waste disposal apparatus.

FIG. 3 is a cross-sectional view showing an injection means of the fast reactor metal sodium waste treatment apparatus.

FIG. 4 is a sectional view of a crushing staircase showing a reaction treatment means of a fast reactor metal sodium waste disposal system.

FIG. 5 is a sectional view of the reaction processing means shown in FIG.

FIG. 6 is a sectional view of the reaction processing means shown in FIG.

FIG. 7 is a sectional view of the reaction processing means shown in FIG.

FIG. 8 is a schematic view showing a conventional alcohol cleaning method.

FIG. 9 is a schematic diagram showing a conventional steam cleaning and water cleaning method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal sodium dispensing means 2 Metal sodium injecting means 3 Cleaning tool 4 Cleaning tank 5 Metal sodium 6 Steam 7 Hot water 8 Valve 9 Metering container 10 Metal sodium supply pipe 11 Metal sodium discharge pipe 12 Pressure gauge 13 Liquid level gauge 14 Insulation material Coating heater 15 Metal sodium injection nozzle 16 Inert gas inflow port 17 Gas dispersion ring 18 Nozzle clogging removal port 19 Inert gas injection nozzle 20 Metal sodium dropping port 22 Blade support rod 23 Vent 24 Blade plate 25 Reaction of metal sodium Processing means 81 Refueling machine 82 Metallic sodium attachment part 83 Exchanger door valve 84 Cleaning tank door valve 85 Cleaning tank 86 Alcohol 87 Water vapor 88 Hot water

Claims (3)

[Claims] A wastewater treatment apparatus for sodium metal in a fast reactor, in which sodium metal in a fast reactor is chemically converted into sodium hydroxide and disposed of in a nuclear reactor, wherein the reactor is disposed of by a metering vessel and a liquid level gauge provided in the metering vessel. Metal sodium metering means for metering a fixed amount of metal sodium per processing unit and sending it out by a gas pressure transfer system, and a metal sodium injection nozzle and an inert gas inlet around the nozzle to prevent the nozzle from being blocked. Means for injecting metallic sodium composed of a gas dispersing ring arranged therein, and a propeller-shaped vane provided in multiple stages via a vane supporting rod for finely scattering dripped metallic sodium, and metallic sodium adhering to the vane From a metallic sodium cleaning tool equipped with multiple steam and hot water outlets to react water with steam and hot water Disposal apparatus FBR metallic sodium with the reaction processing means sodium metal to be made. 2. The disposal apparatus for metallic sodium in a fast reactor according to claim 1, wherein the metallic sodium injection nozzle has a nozzle clogging removal port. 3. An apparatus for disposing of metallic sodium in a fast reactor according to claim 1, wherein the propeller-shaped blades provided in multiple stages are arranged at a pitch of a predetermined angle with respect to each other.