JP3314531B2 - Storage for radioactive contaminants storage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage for a radioactive contaminant storage body, and more particularly to improving the cooling performance of a low heat generation radioactive contaminant storage housed in a storage tube. .

[0002]

2. Description of the Related Art The handling of high-level radioactive waste generated in a nuclear power plant or the like can be improved, for example, by vitrification.

As an example of a storage for storing radioactive waste such as a solidified package for a long period of time, Japanese Utility Model Application Laid-Open No. 3-1252 is disclosed.
No. 99 describes the technique shown in FIG. FIG.
, P is a radioactive contaminant container (vitrified package), 1 is a cell room, 2 is a concrete wall, 3 is a transfer room, 4 is a ceiling slab (ceiling wall), 5 is a storage tube, and 6 is a support structure. An object (support frame), 7 is an outer tube, 8 is an outside air inlet, 9 is an air outlet, 10 is a cooling air passage, and 11 is a closing lid.

In this radioactive waste storage, when the temperature of the storage pipe 5 increases due to the decay heat of the radioactive material, natural convection through which air passes as shown by arrows in FIG. As the air rises in the annular flow path between the storage pipe 5 and the outer pipe 7, the storage pipe 5 and the radioactive contaminant storage body P are cooled.

[0005]

However, when cooling the radioactive contaminant storage body P through the storage pipe 5 by passing cooling air around the storage pipe 5, the inside of the storage pipe 5 is not required. Since the air becomes a heat insulating material and the cooling property of the radioactive contaminant storage body P decreases, and the high-temperature air easily stays inside the storage pipe 5, the radioactive contaminant storage body P and the storage pipe 5
, A large temperature gradient is generated, and the central temperature of the radioactive contaminant storage body P tends to increase. In addition, as shown in FIG. 3, when cooling air is inserted into the annular flow path between the storage pipe 5 and the outer pipe 7 by natural convection, the cooling efficiency becomes low, so that the radioactive contaminant storage is performed. If the body P is in a state of high heat generation, there are problems such as the need to limit the number of storages, the use of forced cooling means, and the need to increase the size of the radioactive waste storage.

[0006] The present invention has been made in view of such circumstances, and aims to achieve the following objects. Improving heat transfer inside the storage tube to promote cooling of the radioactive contaminant storage body. To reduce the temperature gradient to prevent the central part of the radioactive contaminant container from becoming hot. Improve the cooling effect even when using natural convection. To ensure the simplification of the storage structure.

[0007]

A radioactive contaminant container is stored in a storage tube provided inside a cell chamber, and a cooling fluid is inserted through the outside of the storage tube. Gas supply means arranged in a connected state to supply the high thermal conductive gas; and exhaust means arranged in the connected state to exhaust the internal gas , wherein the storage pipe is arranged in an upright state.
And the specific gravity of air inside the storage tube is smaller than that of air.
Filled with heat transfer gas,
The supply means is arranged in the connected state, and
Thus, a configuration in which the exhaust means is arranged in a connected state is employed. High
Helium gas is used as the heat conduction gas . When a plurality of storage pipes are provided, a configuration in which a control valve that opens and closes a flow path of an air supply pipe and an exhaust pipe in each storage pipe is provided to the gas supply means or the exhaust means is added. When the storage tube is arranged in an upright state, a configuration is provided in which an outer tube through which air is inserted by natural convection is arranged around the storage tube. When the storage pipe is arranged in an upright state, a pedestal that supports the load of the radioactive contaminant storage body and buffers the load when the load is applied is disposed below the inside of the storage pipe, A connection portion between the inside of the storage tube and the exhaust means is disposed below the receiving stand, and a configuration in which an air storing portion is disposed between the storing tube and the receiving stand is added.

[0008]

[Function] When storing the radioactive contaminant storage body in the storage pipe, the gas inside the storage pipe is exhausted by the exhaust means,
The space between the storage pipe and the radioactive contaminant storage body is filled with the high thermal conductive gas from the gas supply means. At this time, the high thermal conductive gas
Filling the storage tube will reduce the specific gravity difference between the high thermal conductivity gas and air.
Based on the above, the stagnation moves downward from the upper position,
Inside air is replaced by the high thermal conductive gas. When the temperature of the highly thermally conductive gas rises due to the heat generated by the radioactive contaminants, the storage tube is heated, and by inserting a cooling fluid outside the storage tube,
The storage tube is cooled. At this time, inside the storage tube, heat is removed from the radioactive contaminant storage body by heat transfer by the high thermal conductive gas, and the temperature gradient between the storage tube and the radioactive contaminant storage body is reduced. When the radioactive contaminant storage body is not stored in each storage pipe, or when the amount of heat generated by the radioactive contaminant storage body is low, the amount of the high heat conductive gas fed into the storage pipes is stopped. When the outer pipe is provided when the storage pipe is arranged in the upright state, natural convection occurs around the storage pipe to cool the storage pipe and the radioactive contaminant storage body. When the storage tube is arranged in an upright state,
In the air storage portion between the inside lower part of the storage tube and the cradle, air having a high specific gravity mixed in a gas having a low specific gravity such as helium is separated and stored. When the inside of the storage tube is depressurized with respect to the internal pressure of the cell chamber,
Even if air enters the inside of the storage tube due to leakage, etc., the air with high specific gravity is separated and stored in the air storage unit, and the surrounding area of the radioactive contaminant storage inside the storage tube is cooled as a high thermal conductive gas atmosphere. To secure.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a storage for a radioactive contaminant container according to the present invention will be described below with reference to FIGS.

As shown in FIGS. 1 and 2, in the storage for radioactive contaminant storage according to one embodiment, a plurality of storage pipes 5 are arranged in an upright state inside the cell chamber 1. , Gas supply means 21 and exhaust means 22 are connected to the upper and lower interiors of each storage tube 5 in a connected state.

The gas supply means 21 is provided with a high heat conductive gas G
As shown in FIG. 1, a helium supply source 23 having a gas cylinder of helium gas or the like in a high pressure state, a pressure reducing valve, and the like, and a supply pipe 24 connected to the helium supply source 23 are provided. And a control valve 25 and a pressure gauge 26 arranged in the middle of the supply pipe 24, and an air supply pipe 27 connecting the supply pipe 24 and the upper inside of each storage pipe 5 and arranged in parallel. , A control valve 28 and a pressure gauge 29 which are individually arranged in the air supply pipe 27.

The exhaust means 22 is for sucking and discharging the air inside the storage pipes 5, and as shown in FIG.
And a control valve 31 and a pressure gauge 32 arranged in the middle of the exhaust pipe 30, a suction pipe 33 connected to each exhaust pipe 30, and a storage pipe 5 arranged in the middle of the suction pipe 33. A filter 34 for capturing and removing radioactive substances and the like in the air, a blower 35 in a reduced-pressure atmosphere by sucking air from each storage pipe 5 and the like through a suction pipe 33, and an exhaust gas for releasing the sucked air. And a mouth 36.

As shown in FIG. 2, a pedestal 37 for supporting the load of the radioactive contaminant storage body P or buffering when an impact load is applied is disposed on the inner bottom of the storage pipe 5, as shown in FIG.
A connecting portion 38 for sucking air is provided near the bottom of the storage tube 5 in a connected state inside the storage tube 5, and a receiving stand 37 is provided.
A hollow air storage portion 39 is formed around or inside the space.

As shown in FIG. 2, an outer tube 7 supported by a supporting structure 6 is arranged around the storage tube 5 as in the example of FIG. An annular flow path 40 is formed in the housing 11, and the closing lid 11 has a structure that closes an upper opening of the storage tube 5 with a bolt 11 a and a seal packing 11 b for improving airtightness interposed therebetween.

In the storage for a radioactive contaminant storage body having such a configuration, the radioactive contaminant storage body P
Is stored, suction and discharge of the air inside the storage pipe 5 by the operation of the exhaust means 22 and feeding of the high thermal conductive gas G into the storage pipe 5 by the operation of the gas supply means 21 are performed.

When the exhaust means 22 is operated, the control valve 31 corresponding to the storage pipe 5 storing the radioactive contaminant storage body P is opened, and the interior of the storage pipe 5 and the exhaust pipe 30 are opened. By setting the atmosphere under reduced pressure, the internal air is suctioned and discharged, and radioactive substances and the like contained in the discharged air are filtered by the filter 3.
After being trapped by the exhaust gas 4, the purified air is discharged from the exhaust port 36. Thereafter, the flow path of the exhaust pipe 30 is blocked by each control valve 31.

Next, the gas supply means 21 is operated,
For example, a storage pipe 5 containing a high thermal conductive gas G made of helium gas is used.
When the gas is sent into the upper portion of the storage tube 5, the high thermal conductive gas G is filled into the storage tube 5 based on the specific gravity difference between the helium gas and the air, and the stagnation shifts downward from the upper position. The air is replaced by the high thermal conductive gas G.

When the high thermal conductive gas G is filled into the storage pipe 5 up to the air storage section 39 near the receiving table 37, all the radioactive contaminant storage bodies P stored above the storage pipe 5 are surrounded. , The high thermal conductive gas G is interposed. After filling with the high thermal conductive gas G, the air supply pipe 2 is controlled by each control valve 28.
7 is shut off, and the gas pressure inside the storage pipe 5 is monitored by a pressure gauge 26. This gas pressure is set so as to maintain a reduced pressure atmosphere with respect to the pressure of the air inside the cell chamber 1.

When the temperature of the high thermal conductive gas G rises due to the heat generated by the radioactive contaminant container P, the high thermal conductive gas G
The heat of the radioactive contaminant storage body P is quickly transmitted to the pipe wall of the storage pipe 5 based on the fact that the thermal conductivity of the As the temperature difference becomes smaller, the temperature gradient becomes gentler.

When the outer surface temperature of the storage tube 5 increases, natural convection occurs in the annular flow path 40 between the storage tube 5 and the outer tube 7 as shown by the arrow in FIG. As a result, the temperature rise of the storage pipe 5 is suppressed, and the temperature rise of the radioactive contaminant storage body P inside the storage pipe 5 is also suppressed.

When the pressure of the high thermal conductive gas G is relatively lower than the internal pressure of the cell chamber 1, each control valve 2
It is conceivable that air or the like may enter the inside of the storage tube 5 due to a leakage phenomenon at the cutoff points of the sections 8 and 31. In addition to the detection, even if air is mixed in, the state in which the helium gas stays inside the storage tube 5 is continued, so that the cooling performance in a location where the temperature becomes high does not deteriorate. If the amount of air is small,
Since air having a large specific gravity is stored in the air storage section 39 below the storage pipe 5, the cooling performance can be maintained by interposing the high thermal conductive gas G around the radioactive contaminant storage body P.

When the radioactive contaminant storage body P is not stored in each storage pipe 5 or when the heat generation amount of the radioactive contaminant storage body P is low, the control valve 28, By opening and closing 31, the adjustment of the amount of high heat conductive gas G to be fed into the storage pipe 5 or the stop of the feeding are stopped.

[Other Embodiments] The following technology can be adopted in the storage for radioactive contaminant storage bodies according to the present invention. a) The gas supply means 21 or the exhaust means 22 is connected to an arbitrary number of storage tubes 5. b) A plurality of gas supply means 21 or exhaust means 22 are provided. c) The high thermal conductive gas G is a gas having good thermal conductivity other than helium. d) Instead of the blower 35, a fan, a pump or the like is applied.

[0024]

According to the storage for a radioactive contaminant container according to the present invention, the following effects can be obtained. (1) By adopting a configuration including gas supply means arranged in a connected state inside the storage pipe to supply a high thermal conductive gas and exhaust means arranged in a connected state inside the storage pipe to discharge the internal gas, By sending the high thermal conductive gas into the inside of the storage tube, the heat transfer inside the storage tube is improved, and the cooling of the radioactive contaminant storage body can be promoted. (2) By increasing the heat transfer between the storage pipe and the radioactive contaminant storage body, when a cooling fluid is inserted outside the storage pipe, the temperature gradient inside the storage pipe is reduced and radiation is performed. It is possible to suppress an increase in the temperature of the central portion of the no-pollutant container. (3) A control valve is provided in the pipe of the gas supply means or the exhaust means to switch the supply of high heat conductive gas to the storage pipe according to the level of heat generation of the radioactive contaminant storage body and the presence / absence of storage. The object container can be efficiently cooled. (4) When the storage pipe is arranged in an upright state, the state in which the high thermal conductive gas stays above the inside of the storage pipe by applying helium gas is maintained, and the cooling property in a place where the temperature becomes high is secured. be able to. (5) When the storage pipe is arranged in an upright state, an outer pipe through which air is inserted by natural convection is arranged around the storage pipe, whereby the cooling efficiency by natural convection can be improved. In addition, the structure of the storage can be simplified, and the radioactive waste storage can be prevented from increasing in size. (6) When storing the radioactive contaminant storage body in a high heat generation state, the inside of the storage pipe is made to have a high thermal conductive gas atmosphere and cooling by natural convection is used in combination, and cooling by natural convection is performed when the calorific value decreases. By switching to only, storage management and maintenance can be easily performed. (7) A pedestal and an air storage section are provided below the inside of the storage pipe in an upright state, so that air having a large specific gravity mixed in gas having a small specific gravity can be separated by a specific gravity difference. Separation, in addition to the load supporting and buffering action of the radioactive contaminant storage body, cooling around the radioactive contaminant storage body can be ensured as a high thermal conductive gas atmosphere.

[Brief description of the drawings]

FIG. 1 is a connection diagram showing an embodiment of a storage for a radioactive contaminant storage body according to the present invention.

FIG. 2 is a front sectional view showing a structural example near a storage tube in FIG. 1;

FIG. 3 is a single-focus transparent front sectional view showing a conventional example of a radioactive waste storage.

[Explanation of symbols]

 P Radioactive contaminant storage body (vitrified package) G High thermal conductive gas 1 Cell room 4 Ceiling slab (ceiling wall) 5 Storage tube 6 Support structure (support frame) 7 Outer tube 11 Closure lid 11a Bolt 11b Seal packing 21 Gas Supply means 22 Exhaust means 23 Helium supply source 24 Supply pipe 25 Control valve 26 Pressure gauge 27 Supply pipe 28 Control valve 29 Pressure gauge 30 Exhaust pipe 31 Control valve 32 Pressure gauge 33 Suction pipe 34 Filter 35 Blower 36 Exhaust port 37 Receiving stand 38 connection section 39 air storage section 40 annular flow path

Continuation of front page (56) References JP-A-3-273193 (JP, A) JP-A-3-277998 (JP, A) JP-A-5-107393 (JP, A) JP-A-60-216297 (JP) JP-A-55-155297 (JP, A) JP-A-61-119798 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G21F 9/36 541 G21C 19/06 G21F 7/015

Claims (4)

(57) [Claims] 1. A storage in which a radioactive contaminant storage body (P) is stored in a storage pipe (5) disposed inside a cell chamber (1), and a cooling fluid is inserted outside the storage pipe. A gas supply means (21) connected to the inside of the storage pipe to supply the high thermal conductive gas (G); and an exhaust means (22) connected to the inside of the storage pipe to discharge the internal gas. The storage pipe (5) is arranged in an upright state, and the storage pipe (5) is
Is filled with a high thermal conductivity gas having a lower specific gravity than air.
Gas supply means (21) is connected to the inside of the storage pipe
And the exhaust means (22) is connected to the inside of the lower part of the storage pipe.
Storage for radioactive contaminants storage, characterized in that they are arranged in a storage. 2. A plurality of storage tubes (5) are provided,
Each gas is supplied to the gas supply means (21) or the exhaust means (22).
Of the supply pipe (27) and exhaust pipe (30)
Control valves (28, 31) are provided to open and close the flow path for partitioning.
The radioactive contaminant container according to claim 1, wherein
Storage. 3. A natural convection around the storage pipe (5).
Characterized in that an outer tube (7) to be inserted therethrough is provided.
The storage for a radioactive contaminant container according to claim 1 or 2.
Warehouse. 4. Radioactive contamination below the inside of the storage tube (5).
It supports the load of the object storage body (P) and buffers when the load is applied.
A pedestal (37) is provided, and the
Connection between the inside of the storage tube and the exhaust means (22)
(38) is arranged, and an air storage section is provided between the storage pipe and the receiving stand.
3. The method according to claim 1, wherein (39) is arranged.
Is a storage for the radioactive contaminant storage body according to 3.