JPH0694894A - Silo storing and transporting system for used fuel - Google Patents

Abstract

PURPOSE:To unify equipment, and thereby enhance operating efficiency and safety by housing each canister storing used fuel into an exclusive or normal transporting cask, sending it to a storing site by marine transportation, repacking each canister into the loading cask there, transporting it to a store silo so as to store it, repacking it into a transport cask after its storing period has been over, and thereby transporting it to a disposal plant. CONSTITUTION:Used fuel produced at an atomic power plant 1 is housed in an exclusive or normal transport cask 2 in a form of a canister (DSC 3) both ends of which are covered with shields, or its inner cylinder container (DSC 1) where fuel is stored in, it is forwarded to horizontal silo store facilities 5 by marine transportation 4. In a directly connected and unified packing equipment 7 and storing equipment 8, fuel is repacked in a DSC loading cask means from the transport cask 2 in a form of the DSC 3, so as to be stored in the store silo, after a storing period has been over, the DSC 3 is transferred to the equipment 7 from the silo, it is repacked into the cask 2, and it is then transported to a disposal plant 6 by marine transportation 4. By this constitution, each canister, repack equipment and the like can be commonly utilized, so that operating efficiency is thereby enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to intermediate storage and transportation of spent fuel generated from a nuclear power plant.

[0002]

As horizontal silo storage system of the Related Art Spent fuel is US PN Inc. NUHOMS ^R system. Spent fuel generated from a nuclear power plant is stored in a canister with double-sided shield in a water pool attached to the power plant, transferred to a storage site by a dedicated transportation cask, and then stored and stored in a silo.

In on-site storage, a loading cask for on-site transfer is used to move by a trailer to an independently installed storage silo. These are carried out in the open air. In off-site centralized storage, a dedicated off-site transportation cask is used to transport to a storage site by rail or barge, where it is refilled with a loading cask for on-site transfer and moved to a storage silo by a trailer. These are all carried out in open air.

After the end of the storage period, the canister is taken out of the storage silo by a loading cask for transfer on site, and then refilled into a dedicated off-site transport cask and transported to a disposal site by rail or barge.

[0005]

However, the above-mentioned conventional technique has the following drawbacks. Inadequate measures for marine transportation, dimensionally unusable transportation casks for fuel transportation due to shields on both ends of the canister, relatively large required site area, and difficulty in improving efficiency of operation Inability to operate without being influenced by weather, in applying the design standard in Japan, which is different from the design standard in the US for canisters and concrete silos, structurally insufficient points (shielding, heat removal, storage, earthquake resistance, External missile resistance, criticality, etc.), etc.

Some of these problems have been improved, for example, Japanese Patent Application Nos. 62-323892 and 62-62.
No. 323893, Japanese Patent Application No. 63-95821, Japanese Patent Application No. 1
Although there are inventions described in Japanese Patent Application No. 4879, Japanese Patent Application No. 1-4880, etc., these are partial improvements of the system. To complete the invention of the silo storage / transportation system as a whole, the following systems are further required. Needed to be developed. That is,

(1) A transportation system that enables canister transportation by a transportation cask for ordinary fuel transportation,
(2) Transport system that ensures safety (subcriticality, etc.) during an accident when the canister is submerged in water, (3) Reusable and reusable system that can be used for both dedicated transport cask and regular transport cask both canisters, (4) Receiving / Refilling / Storage /
Canister at the time of unloading / High efficiency system for moving and operating cask and operation rate of equipment, (5) Canister /
It is a storage system with greatly improved performance such as shielding of concrete and silos, heat removal, storage, earthquake resistance, external missile resistance, and criticality.

The present invention has been made in view of the above circumstances, and relates to horizontal silo storage / transportation of spent fuel,
It is an object of the present invention to solve the above technical problems and to provide a system capable of meeting various future needs.

[0009]

The above objects are achieved by a spent fuel silo storage / transportation system as set forth in the appended claims. That is, the spent fuel generated at a nuclear power plant is stored in a horizontal silo storage canister, and the canister is stored in a dedicated transport cask or an ordinary transport cask and transported by sea. Canisters / transport casks that have been transported to the storage site of the storage site, and means for refilling the canisters for silo storage in the silo and transferring the refilled canisters / loading casks to the storage silo location. And storing the canister in the silo, and returning it to the refill facility after the end of the storage period and storing it again in a dedicated cask that can be transported off-site by sea or in a normal transport cask and transport it to a disposal site. Silo storage of spent fuel composed by
Transportation system. The canister is a double containment container consisting of an inner cylinder container with one end shield and an outer cylinder container with one end shield, and has an inner cylinder container that can be stored in a normal transportation cask for fuel transportation. A spent fuel silo storage / transportation system as described, which incorporates a tube assembly basket. The spent fuel silo storage / transportation system according to claim 1, wherein the means for refilling the cask for loading the canister is a refillable common to both the dual containment canister and the inner cylinder canister with one shield. In the means for refilling the canister and the means for storing the canister, receiving / refilling / storage are directly connected and integrated, a dedicated transfer / load cask device is linearly arranged, and the area where the device moves is in the building The spent fuel silo storage and transportation system described in. The storage silo is made of concrete, and the inside air-coolable concrete cask is stored in the storage silo,
Silo storage of spent fuel according to the description in which cooling air flow paths are arranged on the side and rear of adjacent storage silos.
Transportation system. The spent-fuel silo storage / transportation system is described in which the guide tubes of the guide-tube assembly basket are closely assembled, and the tube material is made of a material having a high thermal conductivity. Hereinafter, the operation and the like of the present invention will be described based on Examples.

[0010]

[Embodiments] The means for solving the problems described in the preceding section will be described as follows.

(1) Canister with both ends shielded (hereinafter referred to as D
It is called SC. ) Is an outer cylinder container with a shield (hereinafter referred to as DSCO)
Say. ) And an inner cylinder container with one end shield (hereinafter referred to as DSCI). DSC
Is a dedicated transportation cask, and DSCI can be transported by a regular transportation cask.

(2) A conventional guide sleeve or guide used to store the fuel assembly in the basket.
The lattice is changed to a guide tube and the tube material contains a neutron absorbing material such as boron to ensure subcriticality during submersion in water. Limitation of the material strength and the content of neutron absorbing substances from the processed surface can be dealt with by changing the tube wall thickness.

(3) D from the transport cask into the refill facility
Install a common refill device that can be inserted / pulled out by either SC or DSCI.

(4) Receiving / refilling / carrying out facility (hereinafter referred to as I
It is called TOF. ) And silo storage equipment (hereinafter referred to as HSF) are directly connected and integrated, and a dedicated DSC transfer / load cask device (hereinafter referred to as STTC) consisting of a DSC loading cask loading / traveling vehicle is linearly formed from inside the ITOF to inside the HSF. It is arranged so that it can be run. The running area will have a building structure. This will reduce the site area, facilitate remote automation of DSC transfer and loading, and facilitate all-weather driving operations.

(5) In the storage silo body, a concrete cask (hereinafter referred to as ISCC) having a DSC air cooling passage is installed in a concrete silo (hereinafter referred to as HCSO) having a shielding and impact resistance function. Then, the structure is such that the DSC is housed and fixed inside this. Also HCSO
The outer air flow path is formed by providing a gap space at the side and rear of the adjacent silo. The bulk shield makes the HCSO shield more compact with ISCC installation. Streaming shielding can be reduced to radiation leakage after scattering three or more times by the ISCC internal channel, inter-silo side channel, and silo rear channel. To remove heat from the DSC, the guide / tube material in the basket is made of a material having good thermal conductivity such as an aluminum alloy, and the tubes are closely assembled to improve heat transfer in the DSC. The air flow path in the ISCC is rectified, and the pressure loss of the flow path can be reduced. The air flow path that penetrates the HCSO shielding wall can also reduce the number of bends and shorten the penetration length to reduce the flow path pressure loss. The exhaust stack can be installed independently of the silo, and the chimney effect can be provided by adjusting this height. Since the spent fuel is stored in the dual containment structure of DSC and DSCO, the double storeability can be maintained during all processes of transfer, loading and storage of DSC. Also, after the storage period, it is possible to confirm the DSCI integrity when transporting the DSC off-site if necessary. The seismic resistance of HCSO will be significantly improved as it eliminates the need for a heavy stack to be installed above the silo, which requires shielding for radiation protection. The impact resistance of the storage DSC by the external missile is a double impact prevention structure of the HCSO shielding wall and the ISCC shielding body, so that the missile safety is enhanced.

By taking the above means, in the horizontal silo storage / transportation system, the DSC sea transportation, the use of the normal transportation cask, the efficiency improvement of the DSC silo loading / storage, the drastic improvement of the operation and safety performance of this system. Is achieved. A system capable of satisfying more diverse requirements for spent fuel storage will be possible, and will be able to support future technologies in this field.

An embodiment of the present invention will be described below with reference to FIGS.
, And this will be described sequentially. FIG. 1 is a diagram showing an example of the entire flow of a spent fuel silo storage / transportation system of the present invention. In FIG. 1, 1 is a nuclear power plant, 2 is a dedicated transportation cask or normal transportation cask, and 3 is DSC. Reference numeral 4 is sea transportation, 5 is a horizontal silo storage facility, 6 is a disposal site, 7 is a refill facility, and 8 is a storage facility. Spent fuel generated in the nuclear power plant 1 is stored in a DSC dedicated transportation cask or a DSCI normal transportation cask 2 and is transported by sea transportation 4 to a horizontal silo storage facility 5. Refill facility 7 and storage facility 8 that are directly connected and integrated are refilled and transferred from off-site transportation cask to DSC loading cask device exclusively for the facility in the form of DSC3, and stored in a storage silo with improved performance. To be done. After the end of the storage period, DSC3 is transferred from the silo to the refill facility and DSC3
Alternatively, it is converted into DSCI and is transported to the disposal site 6 by marine transportation 4 by an off-site transportation cask.

FIG. 2 is a view showing an axial cross section of a dual containment structure canister. In FIG. 2, 9 is a shield.
Reference numeral 10 is an outer cylinder container with one end shield, and 11 is an inner cylinder container with one end shield. By accommodating the inner cylindrical container 11 with one end shielded inside the outer cylindrical container 10 with one end shielded, the DSC is configured and at the same time the double storability is always maintained. The power plant that owns the dedicated transportation cask directly stores the DSC in the storage facility, and the power plant that owns only the normal transportation cask is DSCI.
Will be transported to the storage facility. Since DSCI is only provided with a shield at one end, it can be dimensionally transported by a regular transport cask.

FIG. 3 is a diagram showing an example of a common refill facility for DSC and DSCI. The refilling equipment includes the DSC or the DSCI exchanging device 12 installed on the ground floor and the transportation cask installation pit No. installed on the basement floor. 113, Cask Refill Pit No. 214, loading cask installation pit N
o. 315.

The transport cask 18 which was carried in was No. 1 first.
It was installed in the 1st pit 13 and the No. 2 Move and fix to pit 14. Here, the canister (DSC or DSCI) 16 is lifted inside the canister exchanging device 12, and the shielding door 17 of the device is closed. The empty transportation cask is No. Returned to 1 pit 13. Then No. The empty loading cask 19 installed in the 3rd pit 15 is No. It moves to 2 pits 14 and is fixed. The canister 16 in the exchanging device 12 is suspended by opening the shielding door 17 and stored in the loading cask.
o. After returning to the 3 pits 15 and performing the necessary DSC sealing work, the cask lid is attached. In FIG. 3, 20 is a carry-in,
21 is refilling and 22 is loading. Canister replacement device 1
2 is a fixed type, has a necessary shield, and can detect a radioactive leak by sweeping the atmosphere gas inside.

FIG. 4 is a diagram showing an example of a plan layout view of a horizontal silo storage facility 5 in which the receiving / refilling / unloading facility and the storage facility are directly connected and integrated. ITOF accepts transportation cask /
Carry-out room (hereinafter, IOCR) 24, canister exchange room (hereinafter, CCTR) 25, loading cask receiving / carrying room (hereinafter, SCHR) 26 and DSC.
It is composed of a loaded traveling vehicle installation area (hereinafter referred to as SCTA) 27. Storage facility (hereinafter referred to as HCSF)
Is a storage silo arrangement area (hereinafter referred to as CSAA) 2
8, a carriage traveling area (hereinafter, referred to as CTTA) 29, a cooling air introduction / discharge passage area (hereinafter, referred to as ACPA) 30
And a cooling air intake / exhaust pipe installation area (hereinafter referred to as AIEA) 31. The traveling carriage 23 is ITOF
HCSF internal CTTA directly connected to this from the internal installation location
Move in a straight line. The CTTA has a building structure with a roof.

All the canisters carried into this facility are converted into a DSC having a double storage structure and stored in a silo by STTC. The stored DSC is naturally air-cooled in the silo, but air is introduced / released from the silo common flow path. Therefore, no air is exhausted from the individual silos directly into the atmosphere.

FIG. 5 shows a concrete silo (hereinafter referred to as C
It is called S. ) Is an elevation view and FIG. 6 is an example of a plan view thereof. In FIGS. 5 to 6, 32 is an internal air-cooled concrete cask (hereinafter referred to as CC), 33 is a ceiling shield, and 34 is a side. Part shield, 35 is an air passage in the concrete cask, 36 is an air inlet, 37 is an air outlet,
38 is a rear shield, 39 is a front shield, 40 is a flow passage in the silo wall, and 41 is a side flow passage between silos. The CS has a built-in CC 32 independent of this. The flow path of cooling air is
It is composed of upper and lower flow paths that cool the internal DSC of the CC 32, upper and lower flow paths that penetrate the CS wall, upper and lower flow paths that flow between adjacent silo sidewalls, and upper and lower flow paths that flow between adjacent silo rear walls.

7 to 8 are views showing an example of the internal structure of the DSC. FIG. 7 is a sectional view of the guide tube, and FIG. 8 is a guide tube.
It is a figure which shows the state at the time of dense collection of tubes. 7-8
In the figure, 42 is a guide tube and 43 is a spacer disk. The guide tubes 42 containing the spent fuel are closely assembled, and a material having good thermal conductivity such as aluminum alloy is used as the tube material. If necessary, the tube material may contain a neutron absorbing material such as boron or may have its wall thickness increased.

FIG. 9 is a sectional view showing an example of the internal structure of the CC 32, and FIG. 10 is a schematic sectional view showing the structure of the support portion of the CC 32. 9 to 10, 44 is an air outlet, 45
Is a heat shield layer, 46 is a shield concrete, 47 is a lower heat shield plate, 48 is an upper heat shield plate, 49 is a cask support structure, 50 is silo bottom concrete, 51 is silo installation base, and 52 is an air inlet. Inside the CC32, DS
C is accommodated, a flow path is formed to flow air evenly around the DSC, and a heat insulating layer is provided on the inner surface of the CC 32 flow path, so that the CC 32 is directly supported by the silo installation base 51.

[0026]

According to the present invention, the following effects can be obtained as described in the above embodiment. By improving the performance of the common canister, the common refilling device, the integration of the refilling equipment and the storage equipment, and the performance of the storage silo, operational efficiency and safety can be improved. It can reduce the site area of spent fuel storage facilities, enable remote automation of driving operations, and canister loading regardless of weather. In addition to reducing the bulk shielding of the CS by installing the CC, the air flow path arrangement can reduce the radiation leakage after three or more scatterings. The heat removal performance can be improved by adopting an aluminum alloy guide tube and reducing the flow path pressure loss by simplifying the CS internal air flow path. By adopting the double storage structure container, it is possible to constantly maintain the double storage property and ensure high safety. Seismic performance can be improved by not installing an air exhaust pipe on each CS. A double impact resistant structure can be formed by the CS shielding layer and the CC shielding layer to significantly improve the performance of external missile resistance and the like. By configuring the guide / lattice in the fuel assembly bucket with a tube material containing a neutron absorbing substance such as boron, it is possible to secure subcriticality during submersion in water.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of the overall flow of a spent fuel silo storage / transportation system according to the present invention.

FIG. 2 is a view showing an axial cross section of a dual containment structure canister.

FIG. 3 is a diagram showing an example of a common refill facility for DSC and DSCI.

FIG. 4 is a diagram showing an example of a planar layout of a horizontal silo storage facility in which a receiving / refilling / carrying-out facility and a storage facility are directly connected and integrated.

FIG. 5 is a diagram showing an example of an elevation of CS.

FIG. 6 is a diagram showing an example of a plane of CS.

FIG. 7 is a cross-sectional view of a guide tube.

FIG. 8 is a diagram showing a state when the guide tubes are densely assembled.

FIG. 9 is a diagram showing an example of an internal structure of a CC.

FIG. 10 is a schematic cross-sectional view showing the structure of a CC support portion.

[Explanation of symbols]

 1 Nuclear power plant 2 Dedicated transport cask or normal transport cask 3 DSC 4 Sea transport 5 Horizontal silo storage facility 6 Disposal site 7 Refill facility 8 Storage facility 9 Shield 10 One-end shielded outer container 11 One-end shielded inner container 12 Exchanger 13 Pit No. 1 14 Pit No. 215 Pit No. 3 16 canister 17 shield door 18 transport cask 19 loading cask 20 carry-in 21 refilling 22 loading 23 loading cask traveling carriage 24 IOCR 25 CCTR 26 SCHR 27 SCTA 28 CSAA 29 CTTA 30 ACPA 31 CCIA 32 ceiling part 33 ceiling Shield 35 Air passage in concrete cask 36 Air inlet 37 Air outlet 38 Rear shield 39 Front shield 40 Silo wall passage 41 Side passage between silos 42 Guide tube 43 Spacer disc 44 Air outlet 45 Heat shield layer 46 Shield concrete 47 Lower heat shield plate 48 Upper heat shield plate 49 Cask support structure 50 Silo bottom concrete 51 Silo installation base 52 Air inlet

Claims (6)

[Claims] 1. A storage site outside a site of a nuclear power plant, in which spent fuel generated in a nuclear power plant is stored in a horizontal silo storage canister and the canister is stored in a dedicated transport cask or a normal transport cask. A silo can be stored in a silo by receiving a transportation cask (hereinafter referred to as a canister / transport cask) containing a canister that has been transported to a storage site outside the site of a nuclear power plant at the storage site. Means to refill the loading cask for loading inside, means to transfer the refilled canister / loading cask to the storage silo location and store the canister in the silo, and return the canister to the refilling facility after the end of the storage period And then again stored in a dedicated cask or a normal transportation cask that can be transported by sea off the premises and transported to the disposal site. A spent fuel silo storage / transportation system characterized by being configured as follows. 2. A dual containment container in which the canister comprises an inner cylindrical container with one end shield and an outer cylindrical container with one end shield,
The spent fuel silo storage / transportation system according to claim 1, further comprising an inner cylinder container that can be housed in a transportation cask for ordinary fuel transportation, and a boron-containing guide / tube assembly basket. 3. The used according to claim 1, wherein the means for refilling the cask for loading the canister is refillable commonly to both the dual containment vessel canister and the one-end shielded inner cylinder canister. Fuel silo storage and transportation system. 4. In the means for refilling the canister and the means for storing the canister, the receiving / refilling / storage are directly connected and integrated, and a dedicated transfer / load cask device is linearly arranged, and a moving area of the device is provided. The spent fuel silo storage / transportation system according to claim 1, wherein the silo storage / transportation system is in a building. 5. The storage silo is made of concrete, and an internal air-coolable concrete cask is housed in the storage silo, and cooling air passages are arranged at the side and the rear of the adjacent storage silo. The spent fuel silo storage / transportation system according to 1. 6. The silo storage for spent fuel according to claim 2, wherein the guide tubes of the guide tube assembly basket are closely assembled, and the tube material is made of a material having a high thermal conductivity. Transportation system.