CA2567090A1 - Std module. container for storage, transportation and disposal of used nuclear fuel and fuel wastes - Google Patents
Std module. container for storage, transportation and disposal of used nuclear fuel and fuel wastes Download PDFInfo
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- CA2567090A1 CA2567090A1 CA 2567090 CA2567090A CA2567090A1 CA 2567090 A1 CA2567090 A1 CA 2567090A1 CA 2567090 CA2567090 CA 2567090 CA 2567090 A CA2567090 A CA 2567090A CA 2567090 A1 CA2567090 A1 CA 2567090A1
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Classifications
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F5/00—Transportable or portable shielded containers
- G21F5/005—Containers for solid radioactive wastes, e.g. for ultimate disposal
- G21F5/008—Containers for fuel elements
- G21F5/012—Fuel element racks in the containers
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F5/00—Transportable or portable shielded containers
- G21F5/005—Containers for solid radioactive wastes, e.g. for ultimate disposal
Abstract
A container is provided for packaging used nuclear fuel and nuclear fuel waste for the purpose of storage, transportation and disposal. The container comprises a metallic outer shell and an insert, also of metallic construction, designed to maintain used nuclear fuel bundles or other radioactive materials in a specific geometric arrangement in all orientations and to assist in conducting the heat produced by the radioactive materials to the periphery of the container. The container's outer shell and the container lid, including the lid closure weld, provide a permanent, high-integrity containment barrier for its contents.
Description
CONTAINER FOR STORAGE, TRANSPORTATION AND DISPOSAL OF USED
NUCLEAR FUEL, AND OTHER RADIOACTIVE NUCLEAR FUEL WASTES.
1.0 SUMMARY OF THE INVENTION
This invention is directed to a container for packaging used nuclear fuel and other radioactive materials for the purpose of storage, transportation and disposal.
It comprises a metallic vessel of cylindrical shape including an insert, also of metallic construction, which is intended to maintain used nuclear fuel bundles or other radioactive materials in a specific geometric arrangement in ail orientations, and to assist in conducting the heat produced by the radioactive materials to the periphery of the container. The container's outer shell and the container lid, including the lid closure weld, provide a permanent, high-integrity containment barrier for the radioactive materials. In addition to providing a sealed boundary that prevents leakage of radioactive contaminants, the said container protects the integrity of the used nuclear fuel and fuel wastes from the effects of mechanical impact and vibration and from degradation by chemical agents.
The said container is designed to be a core component of storage systems, transportation systems and disposal systems for used fuel and nuclear fuel wastes.
Accordingly, it will be referred to in this Summary and all associated documents as the "STD
Module", or simply "the Module".
The suitability of the Module as a core component of storage, transportation and disposal systems enables it to serve as the basis for an integrated approach to managing the used fuel discharged from CANDU nuclear reactors, right from the time of its removal from the irradiated fuel baythrough to its final disposal in a deep geologic repository. Once used fuel bundles and fuel wastes are loaded in the Module they will not need to be individually handled for re-packaging. The fuel bundles or nuclear fuel wastes packaged in the Module can be placed in an on-site storage facility, or placed in a transportation cask to be moved off-site, or placed into a container designed for final disposal of the waste, while remaining sealed in the STD Module.
The Module capabilities result in substantial economic advantages, derived from the increased simplicity of the facilities and processes required for long-term management of the nuclear fuel wastes. They Module capabiiities result also in increased safety of operations, since the waste will remain permanently sealed within the Module. They also result in increased flexibility for the development and implementation of long-term plans for nuclear fuel waste management.
2.0 CURRENT PRACTICE
In CANDU nuclear power stations, the fuel discharged from the reactors is directly transferred to irradiated fuel bays where it is kept for a minimum period of ten years. The water in the fuel bays provides thermal cooling for the fuel and provides shielding from the radiation emitted by the fuel. After the cooling period, current practice is to remove the fuel from the bays and place it in dry storage at the reactor sites. Two different methods are currently used in Canada for dry storage. At Ontario's commercial power plants, dry storage containers (DSCs) as described in CP 2014065 [1 ] are used. At the New Brunswick and Quebec utilities and at spent fuel storage facilities owned by Atomic Energy of Canada Limited (AECL) the fuel is packaged in fuel baskets, which are stored at the reactor sites in fixed shielding structures made of reinforced concrete. These two methods of storage are briefly described below.
At Ontario's nuclear utilities, after being discharged from the reactors, used fuel bundles are placed in storage trays with a capacity of 24 bundles, which are stacked inside the irradiated fuel bay. Prior to being loaded into DSCs, fuel bundles must be transferred from the trays into a steel structure called storage module, which holds 96 fuel bundles within an array of 48 horizontal steel tubes held by a steel frame. The storage module holds the fuel bundles inside a DSC but it does not provide a containment barrier, the fuel bundles simply sit in the open tubes. Containment during storage is provided by the DSC inner liner.
2.1 DSC LOADING OPERATION
Loading of storage modules into a DSC is done inside the fuel bay. The DSC is submerged in the bay water and lowered onto an impact pad placed at the bottom of the bay. Then, a crane provided with a special tool loads four modules one by one into the DSC. When the loading operation is complete, the DSC is lifted from the bay, drained, and vacuum dried. After this, a temporary lid is placed on the container and a specially designed vehicle moves the DSC to a storage facility within the reactor site, where the container is vacuum-dried a second time and filled with helium before the permanent lid is sealed by a multiple-pas weld. The DSC loading operation is described in further detail in Reference 2.
The weight of a fully loaded DSC (384 fuel bundles) varies in a range from 64 to 80 tons, depending on the density of the aggregate used for the concrete walls which provide shielding for the radioactive load. The DSC is not easily transportable because of its size and weight, and it is not suitable for disposal in a deep geologic repository for several reasons, but primarily because its containment barrier does not meet the service life requirements of a disposal container. Therefore, the fuel bundles stored in DSCs will need to be removed and re-packaged at least once before they are placed in a disposal facility.
This requires cutting open the DSC lid and handling the bundles one by one in a hot cell facility.
2.2 STORAGE BASKET LOADING OPERATION
In Quebec and New Brunswick nuclear utilities and at AECL facilities, used fuel bundles stored in trays at the irradiated fuel bays are loaded one by one in storage baskets, within the fuel bays. After each basket is loaded, it is removed from the bay, its load is dried and the lid is welded in place. Then the basket is transferred to a concrete shielding structure for storage at the reactor site. The structure providing shielding for reactor-site storage of the baskets are either concrete silos or a large volume storage facility called CANSTOR, supplied by AECL. The storage baskets and the shielding structures are designed for a service life of 50 years. Recent studies, however, have determined that under certain conditions the service life of this storage system can be extended up to 100 years. The storage baskets, however, do not meet the requirements for transportation of the spent fuel. Transportation of the fuel bundles in these baskets would result in damage to the fuel. This would present a serious problem at a later time, when the fuel needs to be re-packaged for disposal.
3.0 PROPOSED INNOVATION
The proposed alternative approach described here to existing methods for long-term management of used CANDU fuel consists in loading the used fuel bundles directly from the irradiated fuel bay into STD Modules. The STD Modules can be constructed to have a service life of hundreds of years, and their design meets the requirements for transportation of used CANDU fuel. They are also compatible with current designs of used fuel disposal containers. Therefore, once used CANDU fuel bundles and nuclear fuel wastes are loaded into an STD Module they can remain sealed inside the Module throughout the remaining steps of the fuel cycle. Once the Module is sealed, it becomes the basic handling unit for the nuclear waste. It constitutes a practical modular package providing a permanent containment barrier for the nuclear waste, which will not have to be re-packaged either for transportation or for disposal in a deep geologic repository.
4.0 ADVANTAGES OF THE INNOVATION
The advantages of the proposed approach for managing used CANDU fuel and nuclear fuel waste with respect to existing methods are discussed below.
The STD Module constitutes a suitable container for use as a core component of the most cost efficient systems currently in use for storing used CANDU fuel, such as concrete silos and the CANSTOR system, both designed by AECL. Both, CANSTOR and concrete silos provide radiation shielding and a secondary containment for fuel stored in existing fuel basket designs. Monitoring of the secondary containment provides indication throughout the dry storage period of the status of the primary containment. The benefits of using the STD
Module instead the existing fuel basket designs are that: a) the used fuel doesn't need to be re-packaged for transportation, b) the tighter packaging of the fuel wastes and better heat conduction capabilities result in a better fuel temperature profile within the module, which helps to prevent fuel degradation and c) the Module has a much longer service life which works together with its compatibility with transport and disposal systems, resulting in enhanced flexibility for the planning stage and higher efficiency in the implementation of long-term management of nuclear fuel wastes.
The Module is suitable for transportation of the fuel, via public roads or rail, to a remote facility, either for extended storage or disposal of the nuclear fuel waste. For transportation, the STD Module must be placed in either a road or a rail cask which would provide radiation shielding as well as protection against impact and fire during transport.
The primary advantage of the STD Module with respect to used fuel baskets is that fuel and fuel wastes will not have to be re-packaged. In contrast, used fuel transported in existing fuel baskets, in either vertical or horizontal orientation, would be expected to sustain damage, simply because the baskets were not designed to protect the fuel bundles from mechanical damage during transport. Therefore, receiving and handling of fuel baskets needs to be conducted in a complex hot cell facility where the baskets are cut open and the fuel wastes removed from the baskets and re-packaged, since the baskets are not suitable for disposal of the fuel.
The road casks or rail casks used for transport of STD Modules would be completely re-usable. Under normal conditions, the Module surfaces will be free of loose contamination, therefore its removal from the transport cask would be a simple operation conducted in a shielded facility. After routine safety checks the transport cask would be returned to the point of origin and it would be ready to continue Module shipments. In contrast, used CANDU fuel stored in DSCs presents difficulties in the steps that follow dry storage. Whether the fuel is transported in DSCs, or re-packaged for transport, either a dedicated fuel bay or a hot cell facility would be required for the process of cutting the DSC
open, removing the fuel storage modules and re-packaging the fuel. DSCs are essentially non-reusable, at the end of their service life they become a large mass of radioactive waste.
The dilemma of whether the fuel is removed from DSCs and re-packaged at the reactor-site or DSCs are transported first and retrieval and re-packaging of the used fuel takes place at a remote facility is an question of economics and logistics. In either case complex automated systems operating in large hot cells are required to re-package the nuclear fuel waste and large volumes of contaminated waste are generated in the form of several thousands of opened DSCs. In contrast, transporting the STD modules, where the used fuel bundles and fuel wastes remain permanently sealed is a much simpler and cleaner operation. Placing STD Modules in disposal containers is also a comparatively simple operation.
Redundant levels of safety, longer service life, elimination of the need for re-packaging the fuel, compatibility with re-usable casks resulting in the elimination of large volumes of radioactive wastes, elimination of radioactive contamination, and a dramatic simplification of the interFaces between fuel storage, transportation and disposal of the CANDU fuel wastes are all advantages derived from packaging used CANDU fuel in STD
Modules at the irradiated fuel bays. In a project of the scale of disposal of the Canadian inventory of used nuclear fuel, the savings accrued by packaging the fuel in STD modules are in the billions of dollars.
STD MODULE GEOMETRY
Figure 1 shows the geometry and dimensions of a typical CANDU fuel bundle.
Figure 2 shows a cross-section of the fuel array in a loaded STD Module. The Module has essentially a cylindrical symmetry with each of the fuel bundles occupying one space in a honeycomb pattern. The hexagonal pattem, which constitutes the geometry of the Module insert, provides the most efficient packing of the CANDU fuel bundles. A
series of hexagonal arrays with increasing numbers of cells would provide even higher packing efficiency, however, thermal considerations related to the disposal container make a set of more than sixty bundles unsuitable. Smaller bundle arrays, although suitable for the purpose, result in poor economics for a deep geologic repository system. Therefore, the 54-bundle array illustrated in Figure 2 constitutes the reference cross-section geometry for the STD Module.
Figure 3 illustrates one embodiment of the STD Module consisting of two layers of 54 fuel bundles in the geometry described above. The Module can have a capacity of 54 bundles or, theoretically, any multiple of 54, however, thermal and mechanical considerations make 54-bundle and 108-bundle capacities the most practical configurations.
The same principle of using hexagonal cells for packaging CANDU fuel bundles can be used for packaging used nuclear fuel or fuel wastes of different sizes and geometry. The only geometric constraint that applies is that a Module or a set of Modules should fit inside the disposal container. Other constraints that might apply to the detailed design of the Module type used for a specific kind of nuclear waste (such as research fuel) are related to heat dissipation, criticality and handling.
The Module components that constitute the containment boundary are connected by full welds. All of the components, except the lid, are welded at a Module manufacturing facility. The lid is piaced in the Module at the irradiated fuel bay and sealed by an automatic machine weld inside a shielded enclosure after the Module is removed from the fuel bay.
Some of the lid features include two vent ports, which may be used to purge the Module's inner volume after sealing, and spacers which are needed as interfaces with other modules and systems at different stages of its service life.
MATERIALS OF CONSTRUCTION
The durability of the Module depends on the materials selected for its construction.
Appropriate materials can be selected to meet the required service life as well as any requirements dictated by interfacing systems. For example, an external shell made of stainless steel can provide a reliable primary containment with a service life of hundreds of years. However, the STD Module design can be implemented using any materials of the group specified in the Claims document, to meet specific requirements defined by the user.
The Module inserts may also contain neutron absorbers to reduce the reactivity of the used fuel or fuel wastes and prevent criticality.
REFERENCES
1. Canadian Intellectual Property Office, Patent No. 2,014,065. "Metal-Clad Container for Radioactive Material Storage".
2. "Pickering Waste Management Facility Safety Report". An Ontario Power Generation Report to the Canadian Nuclear Safety Commission (periodically updated in compliance with the requirements of applicable Canadian Nuclear Safety Regulations).
NUCLEAR FUEL, AND OTHER RADIOACTIVE NUCLEAR FUEL WASTES.
1.0 SUMMARY OF THE INVENTION
This invention is directed to a container for packaging used nuclear fuel and other radioactive materials for the purpose of storage, transportation and disposal.
It comprises a metallic vessel of cylindrical shape including an insert, also of metallic construction, which is intended to maintain used nuclear fuel bundles or other radioactive materials in a specific geometric arrangement in ail orientations, and to assist in conducting the heat produced by the radioactive materials to the periphery of the container. The container's outer shell and the container lid, including the lid closure weld, provide a permanent, high-integrity containment barrier for the radioactive materials. In addition to providing a sealed boundary that prevents leakage of radioactive contaminants, the said container protects the integrity of the used nuclear fuel and fuel wastes from the effects of mechanical impact and vibration and from degradation by chemical agents.
The said container is designed to be a core component of storage systems, transportation systems and disposal systems for used fuel and nuclear fuel wastes.
Accordingly, it will be referred to in this Summary and all associated documents as the "STD
Module", or simply "the Module".
The suitability of the Module as a core component of storage, transportation and disposal systems enables it to serve as the basis for an integrated approach to managing the used fuel discharged from CANDU nuclear reactors, right from the time of its removal from the irradiated fuel baythrough to its final disposal in a deep geologic repository. Once used fuel bundles and fuel wastes are loaded in the Module they will not need to be individually handled for re-packaging. The fuel bundles or nuclear fuel wastes packaged in the Module can be placed in an on-site storage facility, or placed in a transportation cask to be moved off-site, or placed into a container designed for final disposal of the waste, while remaining sealed in the STD Module.
The Module capabilities result in substantial economic advantages, derived from the increased simplicity of the facilities and processes required for long-term management of the nuclear fuel wastes. They Module capabiiities result also in increased safety of operations, since the waste will remain permanently sealed within the Module. They also result in increased flexibility for the development and implementation of long-term plans for nuclear fuel waste management.
2.0 CURRENT PRACTICE
In CANDU nuclear power stations, the fuel discharged from the reactors is directly transferred to irradiated fuel bays where it is kept for a minimum period of ten years. The water in the fuel bays provides thermal cooling for the fuel and provides shielding from the radiation emitted by the fuel. After the cooling period, current practice is to remove the fuel from the bays and place it in dry storage at the reactor sites. Two different methods are currently used in Canada for dry storage. At Ontario's commercial power plants, dry storage containers (DSCs) as described in CP 2014065 [1 ] are used. At the New Brunswick and Quebec utilities and at spent fuel storage facilities owned by Atomic Energy of Canada Limited (AECL) the fuel is packaged in fuel baskets, which are stored at the reactor sites in fixed shielding structures made of reinforced concrete. These two methods of storage are briefly described below.
At Ontario's nuclear utilities, after being discharged from the reactors, used fuel bundles are placed in storage trays with a capacity of 24 bundles, which are stacked inside the irradiated fuel bay. Prior to being loaded into DSCs, fuel bundles must be transferred from the trays into a steel structure called storage module, which holds 96 fuel bundles within an array of 48 horizontal steel tubes held by a steel frame. The storage module holds the fuel bundles inside a DSC but it does not provide a containment barrier, the fuel bundles simply sit in the open tubes. Containment during storage is provided by the DSC inner liner.
2.1 DSC LOADING OPERATION
Loading of storage modules into a DSC is done inside the fuel bay. The DSC is submerged in the bay water and lowered onto an impact pad placed at the bottom of the bay. Then, a crane provided with a special tool loads four modules one by one into the DSC. When the loading operation is complete, the DSC is lifted from the bay, drained, and vacuum dried. After this, a temporary lid is placed on the container and a specially designed vehicle moves the DSC to a storage facility within the reactor site, where the container is vacuum-dried a second time and filled with helium before the permanent lid is sealed by a multiple-pas weld. The DSC loading operation is described in further detail in Reference 2.
The weight of a fully loaded DSC (384 fuel bundles) varies in a range from 64 to 80 tons, depending on the density of the aggregate used for the concrete walls which provide shielding for the radioactive load. The DSC is not easily transportable because of its size and weight, and it is not suitable for disposal in a deep geologic repository for several reasons, but primarily because its containment barrier does not meet the service life requirements of a disposal container. Therefore, the fuel bundles stored in DSCs will need to be removed and re-packaged at least once before they are placed in a disposal facility.
This requires cutting open the DSC lid and handling the bundles one by one in a hot cell facility.
2.2 STORAGE BASKET LOADING OPERATION
In Quebec and New Brunswick nuclear utilities and at AECL facilities, used fuel bundles stored in trays at the irradiated fuel bays are loaded one by one in storage baskets, within the fuel bays. After each basket is loaded, it is removed from the bay, its load is dried and the lid is welded in place. Then the basket is transferred to a concrete shielding structure for storage at the reactor site. The structure providing shielding for reactor-site storage of the baskets are either concrete silos or a large volume storage facility called CANSTOR, supplied by AECL. The storage baskets and the shielding structures are designed for a service life of 50 years. Recent studies, however, have determined that under certain conditions the service life of this storage system can be extended up to 100 years. The storage baskets, however, do not meet the requirements for transportation of the spent fuel. Transportation of the fuel bundles in these baskets would result in damage to the fuel. This would present a serious problem at a later time, when the fuel needs to be re-packaged for disposal.
3.0 PROPOSED INNOVATION
The proposed alternative approach described here to existing methods for long-term management of used CANDU fuel consists in loading the used fuel bundles directly from the irradiated fuel bay into STD Modules. The STD Modules can be constructed to have a service life of hundreds of years, and their design meets the requirements for transportation of used CANDU fuel. They are also compatible with current designs of used fuel disposal containers. Therefore, once used CANDU fuel bundles and nuclear fuel wastes are loaded into an STD Module they can remain sealed inside the Module throughout the remaining steps of the fuel cycle. Once the Module is sealed, it becomes the basic handling unit for the nuclear waste. It constitutes a practical modular package providing a permanent containment barrier for the nuclear waste, which will not have to be re-packaged either for transportation or for disposal in a deep geologic repository.
4.0 ADVANTAGES OF THE INNOVATION
The advantages of the proposed approach for managing used CANDU fuel and nuclear fuel waste with respect to existing methods are discussed below.
The STD Module constitutes a suitable container for use as a core component of the most cost efficient systems currently in use for storing used CANDU fuel, such as concrete silos and the CANSTOR system, both designed by AECL. Both, CANSTOR and concrete silos provide radiation shielding and a secondary containment for fuel stored in existing fuel basket designs. Monitoring of the secondary containment provides indication throughout the dry storage period of the status of the primary containment. The benefits of using the STD
Module instead the existing fuel basket designs are that: a) the used fuel doesn't need to be re-packaged for transportation, b) the tighter packaging of the fuel wastes and better heat conduction capabilities result in a better fuel temperature profile within the module, which helps to prevent fuel degradation and c) the Module has a much longer service life which works together with its compatibility with transport and disposal systems, resulting in enhanced flexibility for the planning stage and higher efficiency in the implementation of long-term management of nuclear fuel wastes.
The Module is suitable for transportation of the fuel, via public roads or rail, to a remote facility, either for extended storage or disposal of the nuclear fuel waste. For transportation, the STD Module must be placed in either a road or a rail cask which would provide radiation shielding as well as protection against impact and fire during transport.
The primary advantage of the STD Module with respect to used fuel baskets is that fuel and fuel wastes will not have to be re-packaged. In contrast, used fuel transported in existing fuel baskets, in either vertical or horizontal orientation, would be expected to sustain damage, simply because the baskets were not designed to protect the fuel bundles from mechanical damage during transport. Therefore, receiving and handling of fuel baskets needs to be conducted in a complex hot cell facility where the baskets are cut open and the fuel wastes removed from the baskets and re-packaged, since the baskets are not suitable for disposal of the fuel.
The road casks or rail casks used for transport of STD Modules would be completely re-usable. Under normal conditions, the Module surfaces will be free of loose contamination, therefore its removal from the transport cask would be a simple operation conducted in a shielded facility. After routine safety checks the transport cask would be returned to the point of origin and it would be ready to continue Module shipments. In contrast, used CANDU fuel stored in DSCs presents difficulties in the steps that follow dry storage. Whether the fuel is transported in DSCs, or re-packaged for transport, either a dedicated fuel bay or a hot cell facility would be required for the process of cutting the DSC
open, removing the fuel storage modules and re-packaging the fuel. DSCs are essentially non-reusable, at the end of their service life they become a large mass of radioactive waste.
The dilemma of whether the fuel is removed from DSCs and re-packaged at the reactor-site or DSCs are transported first and retrieval and re-packaging of the used fuel takes place at a remote facility is an question of economics and logistics. In either case complex automated systems operating in large hot cells are required to re-package the nuclear fuel waste and large volumes of contaminated waste are generated in the form of several thousands of opened DSCs. In contrast, transporting the STD modules, where the used fuel bundles and fuel wastes remain permanently sealed is a much simpler and cleaner operation. Placing STD Modules in disposal containers is also a comparatively simple operation.
Redundant levels of safety, longer service life, elimination of the need for re-packaging the fuel, compatibility with re-usable casks resulting in the elimination of large volumes of radioactive wastes, elimination of radioactive contamination, and a dramatic simplification of the interFaces between fuel storage, transportation and disposal of the CANDU fuel wastes are all advantages derived from packaging used CANDU fuel in STD
Modules at the irradiated fuel bays. In a project of the scale of disposal of the Canadian inventory of used nuclear fuel, the savings accrued by packaging the fuel in STD modules are in the billions of dollars.
STD MODULE GEOMETRY
Figure 1 shows the geometry and dimensions of a typical CANDU fuel bundle.
Figure 2 shows a cross-section of the fuel array in a loaded STD Module. The Module has essentially a cylindrical symmetry with each of the fuel bundles occupying one space in a honeycomb pattern. The hexagonal pattem, which constitutes the geometry of the Module insert, provides the most efficient packing of the CANDU fuel bundles. A
series of hexagonal arrays with increasing numbers of cells would provide even higher packing efficiency, however, thermal considerations related to the disposal container make a set of more than sixty bundles unsuitable. Smaller bundle arrays, although suitable for the purpose, result in poor economics for a deep geologic repository system. Therefore, the 54-bundle array illustrated in Figure 2 constitutes the reference cross-section geometry for the STD Module.
Figure 3 illustrates one embodiment of the STD Module consisting of two layers of 54 fuel bundles in the geometry described above. The Module can have a capacity of 54 bundles or, theoretically, any multiple of 54, however, thermal and mechanical considerations make 54-bundle and 108-bundle capacities the most practical configurations.
The same principle of using hexagonal cells for packaging CANDU fuel bundles can be used for packaging used nuclear fuel or fuel wastes of different sizes and geometry. The only geometric constraint that applies is that a Module or a set of Modules should fit inside the disposal container. Other constraints that might apply to the detailed design of the Module type used for a specific kind of nuclear waste (such as research fuel) are related to heat dissipation, criticality and handling.
The Module components that constitute the containment boundary are connected by full welds. All of the components, except the lid, are welded at a Module manufacturing facility. The lid is piaced in the Module at the irradiated fuel bay and sealed by an automatic machine weld inside a shielded enclosure after the Module is removed from the fuel bay.
Some of the lid features include two vent ports, which may be used to purge the Module's inner volume after sealing, and spacers which are needed as interfaces with other modules and systems at different stages of its service life.
MATERIALS OF CONSTRUCTION
The durability of the Module depends on the materials selected for its construction.
Appropriate materials can be selected to meet the required service life as well as any requirements dictated by interfacing systems. For example, an external shell made of stainless steel can provide a reliable primary containment with a service life of hundreds of years. However, the STD Module design can be implemented using any materials of the group specified in the Claims document, to meet specific requirements defined by the user.
The Module inserts may also contain neutron absorbers to reduce the reactivity of the used fuel or fuel wastes and prevent criticality.
REFERENCES
1. Canadian Intellectual Property Office, Patent No. 2,014,065. "Metal-Clad Container for Radioactive Material Storage".
2. "Pickering Waste Management Facility Safety Report". An Ontario Power Generation Report to the Canadian Nuclear Safety Commission (periodically updated in compliance with the requirements of applicable Canadian Nuclear Safety Regulations).
Claims (10)
1. A container for storage, transport and disposal of used nuclear fuel and other nuclear wastes comprising: a vessel of cylindrical shape providing a containment envelope for the nuclear materials, said vessel consisting of a metallic shell, a base, a lid, a metallic insert and central support shaft, with said components having specified mechanical and thermal properties to meet the requirements of the container's functions.
2. A container according to Claim 1 wherein said central support shaft consists of a hollow cylinder designed to accept at either end a tool suitable for lifting and handling the container.
3. A container according to Claim 1 wherein said metallic insert contains a specified number of cells dimensioned to accept one or more CANDU fuel bundles, said cells providing the required support for transport of said nuclear materials in a horizontal position or other suitable orientation.
4. A container according to anyone of claims Claims 1, 2 and 3 wherein said insert cells may have a number of configurations from a set that includes circular, hexagonal or other polygonal cross-sections.
5. A container according to anyone of Claims 1,2, 3 and 4 wherein said insert cells are joined to adjoining cells and or to said container outer shell by welds.
6. A container according to anyone of claims 1, 2, 3, 4 and 5, wherein said insert or any spaces within the insert cells not occupied by fuel or fuel wastes may contain neutron absorbing materials.
7. A container according to anyone of Claims 1,2, 3, 4, 5 and 6 wherein said container materials comprise metals from the group consisting of stainless steel, titanium, aluminum, copper and carbon steel, and said metals may have anti-corrosion coatings containing materials from the group consisting of nickel, chromium and zinc.
8. A container according to anyone of Claims 1,2, 3, 4, 5, 6 and 7 wherein said container materials may have anti-corrosion coatings containing materials from the group consisting of nickel, chromium and zinc.
9. A container according to anyone of Claims 1,2, 3, 4, 5, 6, 7 and 8 wherein said container includes components such as spacer rings, spacer bars and aligning pins that interface with external systems.
10. A container according to anyone of Claims 1, 2, 3, 4, 5, 6, 7, 8, and 9 wherein said container lid is provided with two vent ports that can be used for purging the container volume.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2567090 CA2567090A1 (en) | 2006-10-31 | 2006-10-31 | Std module. container for storage, transportation and disposal of used nuclear fuel and fuel wastes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2567090 CA2567090A1 (en) | 2006-10-31 | 2006-10-31 | Std module. container for storage, transportation and disposal of used nuclear fuel and fuel wastes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2567090A1 true CA2567090A1 (en) | 2008-04-30 |
Family
ID=39367047
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2567090 Abandoned CA2567090A1 (en) | 2006-10-31 | 2006-10-31 | Std module. container for storage, transportation and disposal of used nuclear fuel and fuel wastes |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2567090A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR3027446A1 (en) * | 2014-10-20 | 2016-04-22 | Agence Nat Pour La Gestion Des Dechets Radioactifs | RADIOACTIVE WASTE STORAGE CONTAINER WITH ANTI-CORROSION PROTECTION, METHOD OF MANUFACTURE AND USE OF SUCH A STORAGE CONTAINER |
| US11666939B2 (en) | 2021-02-11 | 2023-06-06 | Nac International, Inc. | Methods for cold spraying nickel particles on a substrate |
-
2006
- 2006-10-31 CA CA 2567090 patent/CA2567090A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR3027446A1 (en) * | 2014-10-20 | 2016-04-22 | Agence Nat Pour La Gestion Des Dechets Radioactifs | RADIOACTIVE WASTE STORAGE CONTAINER WITH ANTI-CORROSION PROTECTION, METHOD OF MANUFACTURE AND USE OF SUCH A STORAGE CONTAINER |
| US11666939B2 (en) | 2021-02-11 | 2023-06-06 | Nac International, Inc. | Methods for cold spraying nickel particles on a substrate |
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