JPH0634797A - Vacuum control device in radioactive substance storage facility - Google Patents

Abstract

PURPOSE:To ensure the profitability and the soundness of a radioactive substance storage facility including a storage for radioactive substance packs, without deteriorating the detection sensitivity for a degree of vacuum in the case of storing several storage containers. CONSTITUTION:A vacuum control device incorporates depressurizing pipe lines 23 which are connected in parallel in each of groups into which several storage containers 21 are divided into, pressure sensors 24 for detecting depressurized conditions, a vacuum degree determining part 25 for selecting vacuum degree data and a vacuum control part 26 for operating a, vacuum generating means 22 in accordance with the selected vacuum degree data. Among the groups, the one having a worst vacuum degree is determined so as to operate the vacuum generating means 22, thereby the vacuum degree in the radioactive substance storage facility is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negative pressure control device for a radioactive substance storage facility.

[0002]

2. Description of the Related Art High-level radioactive waste (waste liquid, etc.) generated in facilities related to a nuclear power plant can be handled easily by vitrification treatment, for example. Then, the radioactive substance storage body such as a solidified package which has been subjected to a treatment such as vitrification is planned to be stored in a radioactive waste storage as shown in FIG. 2 for a long period of time.

In FIG. 2, reference numeral P is a radioactive substance storage body obtained by subjecting high-level radioactive waste to vitrification, etc., 1 is a cell chamber, 2 is a radiation shielding wall (concrete wall), and 3 is a transfer chamber. 4 is a ceiling slab, 5 is a storage pipe (inner pipe), 6 is a support structure (support frame), 7 is an outer pipe, 8 is an outside air inlet, 9 is an air outlet, 10 is an air supply shaft, 11 is an exhaust shaft. , 12 are closing lids, and 13 is a cylindrical cooling flow path.

In the storage cabinet having such a structure, when the temperature of the storage tube 5 rises due to the decay heat of the radioactive material, the air in the cylindrical cooling channel 13 rises to generate convection, as shown by the arrow in FIG. The air taken in from the outside air inlet 8 is passed through to cool the air, and the heated air is discharged from the air outlet 9. Therefore, a power source is not required, cooling is performed by natural convection during decay heat generation, and high safety is ensured regardless of power failure or the like.

In such a facility, it is needless to say that the storage pipe 5 is stored in consideration of safety, earthquake resistance and the like, but the inside of the storage pipe 5 is kept at a pressure lower than that of the surrounding cylindrical cooling flow passage 13. Even if a pinhole or a crack is generated in the storage pipe 5 for some reason, it is possible to prevent the diffusion phenomenon of radioactive material due to the outflow of the internal fluid of the storage pipe 5 to the outside. it can. For example, the actual Kaihei 1-8729
In Japanese Patent Laid-Open No. 9 (radioactive substance storage device), the internal gas of a plurality of storage pipes into which a container for storing a radioactive substance is inserted is individually sucked by a negative pressure generating means, and the pressure in each storage pipe is externalized. A technique for keeping the pressure lower than the pressure is disclosed.

[0006]

However, in a radioactive substance storage facility such as a radioactive substance storage device, the number of storage pipes may reach several hundreds, and the pressure in each storage pipe is managed individually. Then, the equipment cost and management cost of the equipment for that purpose become large, and the practicality is impaired.
When all storage pipes are connected in parallel and the overall negative pressure is attempted to be grasped, even if one of the storage pipes has a defect, it will be leveled as a whole and the sensitivity for detecting abnormalities will decrease. become.

The present invention has been made in view of the above circumstances, and an object thereof is to ensure the economical efficiency and soundness of a radioactive substance storage facility for many storage containers without impairing the detection sensitivity. .

[0008]

A negative pressure control apparatus for a radioactive substance storage facility according to the present invention stores a storage container in a cell chamber, and generates a negative pressure in the storage container with a negative pressure atmosphere inside. A storage facility to which means is connected, in which a large number of storage containers are divided into a plurality of groups, and decompression pipes connected in parallel inside the storage containers of each group, and decompression state connected to the decompression pipes A pressure sensor for detecting the negative pressure level, a negative pressure level determination section connected to a plurality of pressure sensors for selecting the negative pressure level data having the worst condition, and an intervening state between the negative pressure level determination section and the negative pressure generation means. A negative pressure control unit for activating the negative pressure generating means based on the selected and selected negative pressure level data is adopted.

[0009]

Function: A large number of storage containers are monitored while being divided into a plurality of groups. The depressurized state of the depressurized piping of each group is detected by the pressure sensor, and each negative pressure level data is transmitted to the negative pressure level determination unit. In the negative pressure level determination unit, the negative pressure level data is searched for the one with the worst condition, and the negative pressure level is operated based on the negative pressure level data to maintain the negative pressure level. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a negative pressure control device for a radioactive substance storage facility according to the present invention will be described below with reference to FIG. In FIG. 1, reference numeral 20 is a cell chamber, 21 is a storage container, 22 is a negative pressure generating means, 23 is a pressure reducing pipe, 24 is a pressure sensor, 25 is a negative pressure degree determination unit, 26 is a negative pressure control unit, 27.
Is an intake pipe, and 28 is a dust monta.

The cell chamber 20 has a structure surrounded by a radiation shielding wall such as a concrete wall, and the radioactive substance storage device shown in FIG. 2 is applied.

The storage container 21 is, for example, a container in which a radioactive substance is hermetically stored, the storage pipe 5 shown in FIG. 2, and the like, and a large number of them are stored in the cell chamber 20 and a plurality of groups A, It is divided into B, C ...

The negative pressure generating means 22 is a blower or the like arranged in the middle of the suction pipe 27, and a filter or the like for trapping radioactive substances is appropriately arranged in the exhaust passage thereof.

The decompression pipe 23 has a large number of storage containers 21.
However, when the storage containers 21 are divided into a plurality of groups A, B, C ..., Each storage container 21 for each group is connected in parallel, and these are collectively connected to the suction pipe 27.

The pressure sensor 24 is a pressure reducing pipe 2 for each group.
3 and the suction pipe 27, the pressure (depressurized state) of the pipeline is detected, and the negative pressure degree data is obtained by the negative pressure degree determining unit 25.
And to the negative pressure control section 26.

The negative pressure determination unit 25 is connected to each of the pressure sensors 24 of a plurality of groups, compares the detected negative pressure data, and has the worst condition among them (for example, close to atmospheric pressure). Negative pressure data is selected, and it is determined whether the negative pressure exceeds a preset threshold value (standard control range).

The negative pressure control unit 26 is arranged in an intervening state between the negative pressure level determining unit 25 and the negative pressure generating unit 22, and based on the negative pressure level decreasing signal output from the negative pressure level determining unit 25. The negative pressure generating means 22 is operated, and the operating state of the negative pressure generating means 22 is controlled while the overall negative pressure is detected by the pressure sensor 24 of the suction pipe 27.

In such a negative pressure control device for a radioactive substance storage facility, a large number of storage containers 2 are provided inside the cell chamber 20.
By operating the negative pressure generating means 22 with 1 stored, the gas inside all the storage containers 21 is sucked through the pressure reducing pipes 23 of the plurality of groups, and the negative pressure degree of each group is increased. After the negative pressure is kept within the standard control range, the required negative pressure is maintained for each group.

The negative pressure level of each group is detected by the pressure sensor 24 arranged in each pressure reducing pipe 23, and the negative pressure level data of the pressure reducing line 23 of each group is transmitted to the negative pressure level determining unit 25. Hereinafter, the negative pressure determination unit 25 sequentially monitors.

The negative pressure level determination unit 25 compares the transmitted negative pressure level data, finds the worst condition (the one whose negative pressure level is reduced) in each group, and determines the negative value. When the pressure exceeds the threshold value, the negative pressure generating means 22 is activated. By the operation of the negative pressure generating means 22, the internal pressure and the negative pressure of the storage container 21 are set to the required values via the respective pressure reducing pipes 23, and when the negative pressure is recovered, the initial pressure is restored. It is returned to the state.

<Other Embodiments> In the present invention, the following technique can be adopted in place of the embodiment described above. Another negative pressure generating system is connected in series to the negative pressure generating means 22. In that case, the negative pressure generating means 22 should be used only for the pressure reduction adjustment of each storage container 21. The radioactive substance storage body P to be stored in the storage container 21 is other than a vitrified body, for example, a general radioactive waste is packaged or a spent fuel is packaged. An on-off valve is arranged in the middle of the decompression pipe 23 so that each group can be isolated. In the above case, depressurize only the storage container 21 of the group in which the negative pressure is lowered.

[0022]

According to the negative pressure control device for a radioactive substance storage facility according to the present invention, a large number of storage containers accommodated in a cell chamber are divided into a plurality of groups and are connected in parallel within the groups. Piping, a pressure sensor for detecting the depressurized state thereof, a negative pressure determination unit for selecting the negative pressure data having the worst condition, and a negative pressure control unit for operating negative pressure generation means based on the selected negative pressure data. The following effects are obtained because the configuration including the above is adopted. (1) Even when a large number of storage containers are stored in the cell chamber, it is possible to simplify the control of the negative pressure to facilitate control and improve the economical efficiency of the radioactive substance storage facility. (2) Since each decompression pipe divided into a plurality of groups is managed, the soundness of the radioactive substance storage facility can be secured without impairing the detection sensitivity of the negative pressure.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a negative pressure control device for a radioactive substance storage facility according to the present invention.

FIG. 2 is a front sectional view showing a conventional example of a radioactive waste storage.

[Explanation of symbols]

 P Radioactive substance container 20 Cell chamber 21 Storage container 22 Negative pressure generating means 23 Decompression pipe 24 Pressure sensor 25 Negative pressure degree judgment unit 26 Negative pressure control unit 27 Suction pipe 28 Dust monitor

Claims (1)

[Claims] 1. A storage facility in which a storage container is housed in a cell chamber, and negative pressure generating means for creating a negative pressure atmosphere inside the storage container is connected to the storage container. A decompression pipe connected in parallel to the inside of each divided and divided storage container, a pressure sensor connected to the decompression pipe to detect the decompressed state, and a negative pressure sensor connected to a plurality of pressure sensors and having the worst condition. Negative pressure level determining unit for selecting pressure level data, and negative pressure for operating the negative pressure level generating unit based on the selected negative pressure level data arranged in an intervening state between the negative pressure level determining unit and the negative pressure level generating unit. A negative pressure control device for a radioactive substance storage facility, comprising a control unit.