JPH10197689A - High-level liquid waste sampler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-level liquid waste sampler which needs no dedicated air lift pump, does not require washing the sampler after sampling, and has a simple structure. SOLUTION: A sampling pot 31 is placed at some midpoint in a transportation pipe 15, and a transportation pipe 15b on the downstream side is allowed to communicate with the bottom of the sampling pot 31. A freezed valve 33 is located near the sampling pot 31 of the transportation pipe 15b, and an overflow pipe 32 is installed halfway between the downstream side of the freezed valve 33 and the sampling pot 31. The supply of liquid nitrogen to the freezed valve 33 outside the transportation pipe 15b freezes a liquid in it to stop the flow of the liquid, and allows it to overflow, and then a high-level liquid waste stored in the sampling pot 31 is sampled. After the completion of sampling, the high-level liquid waste in the transportation pipe 15b is dissolved by stopping the supply of the liquid nitrogen, and then the liquid waste is discharged from the bottom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for sampling high-level liquid waste, and more particularly to an apparatus for sampling the radioactivity level and composition of high-level liquid waste generated by reprocessing spent fuel at a nuclear facility. Can be installed also as a transfer pipe.

[0002]

2. Description of the Related Art Radioactive waste generated by the reprocessing of spent fuel in a nuclear facility is sealed and stored in a storage container according to the radioactivity level for storage management.

[0003] High-level liquid waste, which is one of the radioactive wastes, is generated, for example, in the process of reprocessing spent fuel, and high-level liquid waste generated in a reprocessing plant is, as shown in FIG. After being received in the receiving tank 1, it is sent to the glass melting furnace 5 via the concentration tank 2, the concentrated liquid tank 3 and the concentrated liquid supply tank 4, sealed as a vitrified body 6 in a vitrified container 7, and stored in a storage facility. Will be kept.

Normally, in each of the storage tanks 1, 2, 3, 4 and the like for storing high-level waste liquid, for example, as shown in FIG. 3, a waste liquid transfer device 10 is provided. An air lift pump 13 is provided in the waste liquid storage tank 11 to transfer the waste liquid to the waste liquid storage tank 12, and can be transferred to the waste liquid storage tank 12 via the gas-liquid separator 14 and the transfer pipe 15.

[0005] In the process of treating such high-level waste liquid,
It is necessary to check the radioactivity level and composition of the waste liquid in the storage tank where the high-level waste liquid of each process is stored about once every 1 to 6 months. Sampling is performed.

The high-level waste liquid sampling device 20
For example, as shown in FIG. 3, an air lift pump 21 is provided separately from the waste liquid transfer device 10 in the waste liquid storage tank 11 for storing the high-level waste liquid to be sampled, and the sampling pot 22 above the waste liquid storage tank 11 is provided. While sending waste liquid, overflow pipe 2
A part of the waste liquid to be pumped is provided and circulated by returning the waste liquid to the waste liquid storage tank 11, and the sampling device 24 samples the radioactivity level and the like using the waste liquid stored in the sampling pot 22.

[0007]

In this sampling apparatus 20, a sampling liquid is stored in a sampling pot 22, and an overflow pipe 23 is provided in the sampling pot 22.
However, if a simple structure is used to provide a valve at the bottom of the sampling pot 22, the valve needs to be maintained, and the valve must be installed in the radiation shielding wall. Can not. For this reason, if a solid content is contained in the sampling liquid at the bottom of the sampling pot 22, it is necessary to wash the sampling device 20 such as the sampling pot 22 by supplying water or the like after the sampling, since the solid content is deposited. There's a problem.

The sampling device 20 itself is
There is a problem that a dedicated device such as an air lift pump 21 is required even though the device is used only about once every six months.

The present invention has been made to solve the problems of the conventional concept, and does not require a dedicated air lift pump or piping, does not require cleaning after sampling, and has a simple and high-level structure. It is intended to provide a liquid waste sampling device.

[0010]

In order to solve the above-mentioned problems, a high-level liquid waste sampling apparatus according to the present invention has a sampling pot disposed in the middle of a high-level liquid waste transfer pipe and a high-level liquid waste transfer pipe. While the downstream end is connected to the bottom of the sampling pot, a frozen valve is provided near the sampling pot on the downstream transfer pipe, and a downstream side of the frozen valve and an intermediate portion between the sampling pot are provided. An overflow pipe is provided.

According to the high-level liquid waste sampling apparatus, the sampling pot is disposed in the middle of the transfer pipe, the downstream transfer pipe communicates with the bottom of the sampling pot, and the transfer pipe is frozen near the sampling pot. In addition to providing a freed valve, an overflow pipe is provided downstream of the frozen valve and in the middle of the sampling pot, and a cooling medium such as liquid nitrogen is supplied to the frozen valve outside the transfer pipe for transfer. Freezes the liquid in the pipe to stop the flow of the high-level waste liquid and causes it to overflow, samples the high-level waste liquid stored in the sampling pot, and stops the supply of the cooling medium after completion to stop the high-level waste liquid in the transfer pipe. To release the water from the bottom.

This eliminates the need for an air lift pump and dedicated piping for sampling, simplifies the structure, eliminates the need to clean the sampling pot, etc., and facilitates maintenance and the like.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram according to an embodiment of the high-level liquid waste sampling apparatus of the present invention.

The high-level liquid waste sampling device 30 discharges the waste liquid from the waste liquid storage tank 11 where the high-level liquid waste to be sampled is stored to the waste liquid storage tank 12 via the air lift pump 13 and the gas-liquid separator 14. It is installed using a waste liquid transfer device 10 such as a transfer pipe 15 for transferring.

In this high-level liquid waste sampling apparatus 30, a sampling pot 31 is disposed in the middle of a transfer pipe 15 as shown in FIG. 1, and a transfer pipe 15a on the upstream side from the gas-liquid separator 14 is sampled. An end portion of a downstream transfer pipe 15 b that is communicated with the intermediate portion of the pot 31 and communicates with the waste liquid storage tank 12 is attached to communicate with the bottom of the sampling pot 31.

An overflow pipe 32 is attached to the sampling pot 31 so as to communicate with a position corresponding to the liquid level required for sampling, and is attached so that the other end communicates with the downstream transfer pipe 15b. It is.

A frozen valve 33 is mounted near the sampling pot 31 on the downstream transfer pipe 15b communicating with the bottom of the sampling pot 31 so as to surround the outside of the transfer pipe 15b. The liquid in the transfer pipe 15b surrounded by the frozen valve 33 is frozen by supply and discharge of a cooling medium such as the liquid, so that the liquid can be closed or melted and opened as a fluidized state.

A sampling device 34 for checking the radioactivity level and composition is attached to such a sampling pot 31 so that the tip is near the bottom.

In the high-level liquid waste sampling apparatus 30 configured as described above, when sampling the high-level liquid waste in the waste liquid storage tank 11, first, a cooling medium such as liquid nitrogen is supplied to the frozen valve 33. The liquid is supplied to freeze the liquid in the transfer pipe 15b, and the bottom of the sampling pot 31 is closed.

Then, the waste liquid pumped from the waste liquid storage tank 11 by the air lift pump 13 is sent into the sampling pot 31 via the gas-liquid separator 14, gradually accumulates at the bottom, and accumulates at the overflow pipe 32. ,
It overflows and is transferred to the waste liquid storage tank 12 via the transfer pipe 15b on the downstream side.

In this manner, the state in which the waste liquid to be sampled is accumulated up to the overflow pipe 32 is held in the sampling pot 31, and the accumulated waste liquid is sampled by the sampling device 34.

On the other hand, after the sampling is completed, when the supply of the cooling medium to the frozen valve 33 is stopped, the frozen waste liquid in the transfer pipe 15b is thawed to be in a fluidized state and the valve is opened. After the waste liquid and solids collected at the bottom of the sampling pot 31 are transferred to the waste liquid storage tank 12, the waste liquid pumped from the waste liquid storage tank 11 is sequentially transferred via the downstream transfer pipe 11b.

Therefore, according to the high-level liquid waste sampling device 30, the sampling pot 31 and the frozen valve 33 and the like can be used in combination with the waste liquid transfer device 10 without providing an independent air lift pump or the like. The high-level liquid waste to be sampled can be collected and sampled in the sampling pot 31, so that the structure can be simplified and the device can be installed at low cost.

Further, since the downstream transfer pipe 15b communicates with the bottom of the sampling pot 31 and the frozen valve 33 is provided, the waste liquid collected at the bottom of the sampling pot 31 after sampling is completely removed together with the solid content. To prevent solid deposition and eliminate the need for washing.

Further, since the frozen valve 33 is provided as a valve for opening and closing the bottom of the sampling pot 31, there is no need for maintenance unlike a mechanical valve, and the valve can be installed in the radiation shielding wall. it can.

In the above embodiment, the high-level liquid waste generated by the reprocessing of the spent fuel in the nuclear reactor has been described as a sampling target. However, the present invention is not limited to this, and is widely applied to the sampling of high-level liquid waste. You can do it.

[0027]

According to the high-level liquid waste sampling apparatus of the present invention, the sampling pot is arranged in the middle of the transfer pipe and the downstream transfer pipe is provided. Is connected to the bottom of the sampling pot, a frozen valve is provided near the sampling pot of the transfer pipe, and an overflow pipe is provided downstream of the frozen valve and an intermediate portion of the sampling pot. Supplying a cooling medium such as liquid nitrogen to the frozen valve outside the tank, freezes the liquid in the transfer pipe, stops the flow of the high-level waste liquid, causes overflow, and performs sampling of the high-level waste liquid stored in the sampling pot. After completion, supply of the cooling medium is stopped to remove high-level waste liquid in the transfer piping. However can be discharged from the bottom, it is possible to prevent the deposition of such solids.

This eliminates the need for an independent air lift pump or dedicated piping for dedicated sampling, allows the structure to be simplified also as a waste liquid transfer device, and also necessitates cleaning of the sampling pot and the like. And maintenance becomes easy.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram according to an embodiment of a sampling device for high-level liquid waste of the present invention.

FIG. 2 is a schematic explanatory view of a reprocessing step of a spent fuel in a nuclear facility.

FIG. 3 is a schematic configuration diagram of a high-level liquid waste sampling device that has been considered up to now.

[Explanation of symbols]

 Reference Signs List 10 waste liquid transfer device 11 waste liquid storage tank (upstream side) 12 waste liquid storage tank (downstream side) 13 air lift pump 14 gas-liquid separator 15 transfer pipe 15a upstream transfer pipe 15b downstream transfer pipe 30 high-level liquid waste sampling device 31 sampling pot 32 overflow piping 33 frozen valve 34 sampling equipment

Claims (1)

[Claims] 1. A sampling pot is arranged in the middle of a transfer pipe for high-level liquid waste, and a downstream end of the transfer pipe is connected to a bottom of the sampling pot. A high-level liquid waste sampling apparatus comprising: a frozen valve provided near a pot; and an overflow pipe provided downstream of the frozen valve and an intermediate portion of the sampling pot.