CA2622547A1 - Pressurized fuel channel type nuclear reactor - Google Patents
Pressurized fuel channel type nuclear reactor Download PDFInfo
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- CA2622547A1 CA2622547A1 CA002622547A CA2622547A CA2622547A1 CA 2622547 A1 CA2622547 A1 CA 2622547A1 CA 002622547 A CA002622547 A CA 002622547A CA 2622547 A CA2622547 A CA 2622547A CA 2622547 A1 CA2622547 A1 CA 2622547A1
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- Prior art keywords
- fuel
- reactor
- fuel assembly
- pressure tube
- pressure
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
- G21C3/02—Fuel elements
- G21C3/04—Constructional details
- G21C3/06—Casings; Jackets
- G21C3/14—Means forming part of the element for inserting it into, or removing it from, the core; Means for coupling adjacent elements, e.g. to form a stringer
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C19/00—Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel
- G21C19/02—Details of handling arrangements
- G21C19/12—Arrangements for exerting direct hydraulic or pneumatic force on fuel element or on control element
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C19/00—Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel
- G21C19/14—Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel characterised by their adaptation for use with horizontal channels in the reactor core
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C19/00—Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel
- G21C19/20—Arrangements for introducing objects into the pressure vessel; Arrangements for handling objects within the pressure vessel; Arrangements for removing objects from the pressure vessel
- G21C19/202—Arrangements for handling ball-form, i.e. pebble fuel
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C19/00—Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel
- G21C19/20—Arrangements for introducing objects into the pressure vessel; Arrangements for handling objects within the pressure vessel; Arrangements for removing objects from the pressure vessel
- G21C19/205—Interchanging of fuel elements in the core, i.e. fuel shuffling
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Monitoring And Testing Of Nuclear Reactors (AREA)
Abstract
The present invention provides a PWR or CANDU nuclear reactor having a greatly simplified on-power refueling by using a reactor coolant flow instead of existing fuelling machine head and auxiliary equipment. This newly developed reactor completely eliminates the pressure tube plugs (in the range of 1000 per reactor), fuelling machine trolleys, fuelling ducts, fuelling heads, thus eliminating potential leaks of the reactor coolant, reducing the size of the reactor building, simplifying operations, maintenance, and greatly reducing the capital and O&M
cost of the fuel handling equipment.
cost of the fuel handling equipment.
Description
PRESSURIZED FUEL CHANNEL TYPE NUCLEAR REACTOR
TECHNICAL FIELD OF INVENTION
The present invention relates to nuclear reactors. More specifically, the present invention relates to pressurized fuel channel type reactors, for example, the water-cooled reactors, including pressurized water reactors (PWR) and pressurized heavy water reactors (PHWR), and, specifically, CANDU reactors for nuclear power plants.
BACKGROUND OF THE INVENTION AND PRIOR ART
Pressurized fuel channel type reactors are well known. A pressurized fuel channel type reactor (a reactor in the following text) comprises a group of fuel channels. A fuel channel comprises a horizontal or vertical pressure tube positioned in a moderator and containing fuel assemblies (fuel bundles). The reactor also comprises a reactor coolant circulation system comprising a group of pumps and providing circulation of the reactor coolant through the fuel channels, and a fuel handling apparatus (fuelling machine) for insertion of fuel assemblies into the pressure tubes and removal of fuel assemblies from the pressure tubes.
A reactor coolant is usually represented by light water, heavy water (in latter case a reactor is also known as a pressurized heavy water reactor (PHWR), represented by CANDU reactors), but there are many other coolants potentially available (liquid metal, molten salts, etc.). A reactor coolant circuit consists of a reactor, a heat consumer (usually a primary side of boilers in case of nuclear power plant), and reactor coolant pumps. The reactor coolant is pumped between fuel elements of fuel assemblies located in the fuel channels absorbing the heat generated by fuel elements and usually through the tube side of boilers of the nuclear power plant releasing the heat. The coolant further returns to the reactor coolant pump and to the reactor channels. The fuel handling apparatus (fuelling machine) consists of trolleys, fuelling heads comprising various mechanical and hydraulic devices to attach the fuelling heads to the both ends of the pre-selected pressure tube, remove and re-install the pressure tube plugs, insert a new fuel assembly into the pressure tube and remove the spent fuel assembly from another end of the pressure tube, a magazine containing the fuel assemblies, a heat exchanger and a circulation pump for cooling the removed fuel assemblies, control and instrumentation.
The pressurized fuel channel type reactors are described in the following patent applications or patents granted in Canada:
1066434 Isaac, Peter 2283647 Sollychin, Rayman The patent No. 2283647 that discloses a pressurized fuel channel type reactor having fuel channels, containing fuel assemblies (fuel bundles) aligned in pairs to reduce a hydraulic resistance of the fuel channel.
The closest prior art is the patent No. 1066434 discloses a pressurized fuel channel type reactor having horizontally extending fuel channels, a reactor coolant circulation system, and a fuel handling apparatus (fuelling machine) for insertion and removal of fuel assemblies into and from the fuel. The fuel handling apparatus comprises piston members assisting the process of fuel removal during on-line refueling.
The prior art does not sufficiently address an issue of on-line refueling that requires opening both the upstream and the downstream ends of the fuel channel filled with high temperature reactor coolant being under high pressure (10 MPa or higher). This operation is performed by a very complex and expensive fuelling machine. Any malfunction of the fuelling machine results in a forced shut down of the reactor and associated losses in generation in the range of $ 1,000,000 per day. There is also a potential for a loss of reactor coolant in the form of minor leaks from the connection points or even a complete loss of the reactor coolant in case of failure of the fuelling head to re-install correctly the pressure tube plug.
In addition, the prior art does not address high operation and maintenance (O&M) expenses and very high cost of the fuelling machine (fuel handling apparatus). The fuelling machine maintenance is further complicated by high radiation fields it is exposed to during on-line refueling thus making all the parts of the fuelling machine highly radioactive.
SUMMARY OF THE INVENTION
The present application develops the prior art to simplify the process of fuelling of the reactor. A pressurized fuel channel type reactor (a reactor in the following text) comprises a group of fuel channels. A fuel channel comprises a horizontal or vertical pressure tube positioned in a moderator and containing fuel assemblies (fuel bundles). The reactor also comprises a reactor coolant circulation system comprising a group of pumps and providing circulation of the reactor coolant through the fuel channels. A reactor coolant can be represented by light water or heavy water, but there are many other coolants potentially available (liquid metal, molten salts, etc.). A reactor coolant circuit consists of a reactor, a heat consumer (usually a primary side of boilers in case of nuclear power plant), and reactor coolant pumps. The reactor coolant is pumped between fuel elements of fuel assemblies located in the fuel channels absorbing the heat generated by fuel elements and usually through the tube side of boilers of the nuclear power plant releasing the heat. The coolant further returns to the reactor coolant pump and to the reactor channels. Fuel assembly has a capability of moving rollably in the pressure tubes and in pipes with the flow of the reactor coolant, for example, by having a spherical shape. A fuel assembly distribution header is connected to the pressure tube inlets and has a plurality of hydraulic cylinders controlling movement of fuel assemblies from fuel assembly distribution header into the pressure tube inlets. Functions of the part of the hydraulic cylinders can be performed by nozzles, connected to the source of the high-pressure reactor coolant and producing small jets of the reactor coolant directing each fuel assembly into the predetermined pressure tube. A fuel assembly collection header is connected to pressure tube outlets and has a plurality of hydraulic cylinders controlling the movement of fuel assemblies from the pressure tube outlets into the fuel assembly distribution header. This newly developed reactor completely eliminates the pressure tube plugs (in the range of 1000 per reactor), fuelling machine trolleys, fuelling heads, thus eliminating potential leaks of the reactor coolant, simplifying operations, maintenance, and greatly reducing the capital and O&M cost of the fuel handling.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of the pressurized fuel channel type nuclear reactor having horizontal fuel channels and individual fuel supply and removal pipes equipped with hydraulic cylinders controlling the movement of the fuel assemblies according to one embodiment of the present invention and corresponding to the claims 1, 2, 3, 4, 6, 7.
FIG. 2 is a schematic representation of the pressurized fuel channel type nuclear reactor having horizontal fuel channels, a fuel assembly distribution header, and a fuel assembly collection header, equipped with hydraulic cylinders controlling the movement of the fuel assemblies according to the embodiment of the present invention and corresponding to the claims 1, 2, 3, 4, 6, 7, 8, and 9.
FIG. 3 is a schematic representation of the pressurized fuel channel type nuclear reactor having horizontal fuel channels, a fuel assembly distribution header, and a fuel assembly collection header, equipped with hydraulic cylinders controlling the movement of the fuel assemblies according to the embodiment of the present invention and corresponding to the claims 1, 2, 3, 4, 6, 7, 9, and 10.
FIG. 4 is a schematic representation of a fuel assembly having a capability of moving rollably in the pressure tubes and in the pipes of the fuel handling apparatus according to the embodiment of the present invention and corresponding to the claims 1, 2, 3, 4, and 5. The fuel assembly comprises cylindrical fuel elements positioned radially within a spherical shell having a plurality of holes for circulation of the reactor coolant.
FIG. 5 is a schematic representation of a fuel assembly having a capability of moving rollably in the pressure tubes and in the pipes of the fuel handling apparatus according to the embodiment of the present invention and corresponding to the claims 1, 2, 3, 4, and 5. The fuel assembly comprises spherical fuel elements positioned within a spherical shell having a plurality of holes for circulation of the reactor coolant.
FIG. 6 is a schematic representation of a spherical fuel element.
FIG. 7 is a schematic representation of a part of the fuel assembly distribution header with two fuel assemblies shown. The movement of the fuel assemblies along the header is restricted by stems being a part of the hydraulic cylinder assembly (not shown).
Parts that are not essential to the invention and well known in power generation industry, such as details of the moderator design, end fittings, reactor coolant circulation system, boilers, control and instrumentation equipment, etc., are not shown.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1 of the drawings, a pressurized fuel channel type reactor (a reactor in the following text) comprises a group of fuel channels positioned in a moderator 1. A fuel channel comprises a horizontal pressure tube 2 (as shown) positioned inside the calandria tube 3 providing a thermal insulation layer between the pressure tube and the moderator. A vertical pressure tube arrangement is not shown. The pressure tubes contain fuel assemblies (fuel bundles). The reactor also comprises a reactor coolant circulation system comprising a group of pumps (not shown) and providing circulation of the reactor coolant through the fuel channels. A reactor coolant can be represented by light water or heavy water, but there are many other coolants potentially available (liquid metal, molten salts, etc.). A reactor coolant circuit consists of a reactor, a heat consumer (usually a primary side of boilers in case of nuclear power plant), and reactor coolant pumps. The reactor coolant is pumped between fuel elements of fuel assemblies located in the fuel channels absorbing the heat generated by fuel elements and usually through the tube side of boilers of the nuclear power plant releasing the heat. The coolant further returns to the reactor coolant pump and to the reactor channels.
A hydraulic cylinder is a device comprising a cylindrical hollow body with a piston.
The piston has an ability to move inside the cylinder along its axis depending on a pressure difference applied to the opposite piston surfaces. The stem (rod) is attached to the piston in the axial direction and moves with it. The hydraulic cylinder is attached (welded) to the fuel handling apparatus pipe and, depending on its position, either prevents or allows the movement of the fuel assembly with the flow of the reactor coolant.
Fuel assembly has a capability of moving rollably in the pressure tubes and in pipes with the flow of the reactor coolant by having a spherical or close to spherical shape. Each pressure tube 2 has two connections to the reactor coolant circulation system. Inlet of the pressure tube 2 is connected to the pipe of the fuel handling apparatus supplying new fuel assemblies 4. The pipe of the fuel handling apparatus is connected to the reactor coolant circulation system having an equal or higher pressure than the pressure of the reactor coolant at the inlet of the pressure tube 2 (not shown). The pipe of the fuel handling apparatus has two hydraulic cylinders 8, each of them having a piston and attached stem that moves into the pipe of the fuel handling apparatus controlling the movement of the fuel assemblies with the flow of the reactor coolant. The piston moves along the axis inside the cylindrical vessel to and from the pipe of the fuel handling apparatus depending on the pressure difference on opposite sides of the piston generated by external source of pressure (not shown). The stem can be of any form (shape) including being an elongated concave plate having passages for the reactor coolant (not shown), or having the end of the stem split in two rods as shown on Fig. 7.
To remove one used fuel assembly from the pressure tube 2, the stem 9 of the right (as seen on Fig.1) of two hydraulic cylinders 8, located downstream of the outlet of the pressure tube 2, retracts, and the first fuel assembly 4 moves rollably with the flow from the outlet of the pressure tube 2 and stops when it reaches the used fuel storage location outside the reactor (not shown). After that, the stem 9 returns to previous position (extends into the pipe).
Similarly, when the stem 9 of the left (as seen on Fig.1) of two hydraulic cylinders 8, located at the outlet of the pressure tube 2, retracts, all fuel assemblies positioned upstream of the stem inside the pressure tube 2 move rollably with the reactor coolant flow toward the outlet of the pressure tube 2 until the first of them reaches the extended stem 9 of the right hydraulic cylinder 8.
To insert one new fuel assembly into the pressure tube 2, the stem 9 of the lower (as seen on Fig.1) of two hydraulic cylinders 8, located upstream of the inlet of the pressure tube 2, retracts, one new fuel assembly 4 moves rollably with the flow toward the inlet of the pressure tube 2 and stops when it reaches the first (from the left side) fuel assembly positioned in the pressure tube 2. After that, the stem 9 returns to previous position (extends into the pipe). Similarly, when the stem 9 of the upper (as seen on Fig.1) of two hydraulic cylinders 8 retracts, all new fuel assemblies positioned upstream of the stem move rollably with the reactor coolant flow toward the inlet of the pressure tube 2 until the first of them reaches the extended stem 9 of the lower hydraulic cylinder 8.
Referring to FIG. 2 of the drawings, a pressurized fuel channel type reactor is provided with a fuel assembly distribution header 10 (a pipe) connected to the group of the pressure tube 2 inlets and has two hydraulic cylinders 8 controlling a movement of the fuel assemblies 4 into the fuel assembly distribution header 10, and a plurality of hydraulic cylinders 8, each of them controlling movement of fuel assemblies 4 from fuel assembly distribution header into each pressure tube 2 inlet of the group. When a new fuel assembly 4 is released, it moves with the flow of the reactor coolant passing all hydraulic cylinders 8 having their stems 9 retracted until it reaches the hydraulic cylinder having its stem 9 extended directing the fuel assembly 4 toward the predetermined pressure tube 2. At that place, the fuel assembly 4 leaves the fuel assembly distribution header 10 and moves toward the pressure tube 2 inlet. To ensure that the fuel assembly does not enter another pressure tube (not predetermined), the fuel assembly distribution header 10 is slightly curved (not shown). Subsequently, the fuel assembly moves rollably in the fuel assembly distribution header being in contact with the header internal side opposite to the pipe branch leading to the pressure tube 2 inlet. This modification requires significantly less hydraulic cylinders.
The reactor is also provided with a fuel assembly collection header 11 (a pipe) connected to the group of the pressure tube outlets. Two hydraulic cylinders 8 control the movement of the fuel assemblies 4 from each of the pressure tubes into the fuel assembly collection header 11.
Referring to FIG. 3 of the drawings, a pressurized fuel channel type reactor is provided with a fuel assembly distribution header 10 (a pipe) connected to the group of the pressure tube inlets and has two hydraulic cylinders 8 controlling a movement of the fuel assemblies 4 into the fuel assembly distribution header 10, and a plurality of hydraulic nozzles 12, each of them controlling movement of fuel assemblies 4 from the fuel assembly distribution header 10 into each pressure tube inlet of the group. Functions of the part of the hydraulic cylinders are performed by nozzles 12, connected to the source of the high-pressure reactor coolant and producing small jets of the reactor coolant directing each fuel assembly into the predetermined pressure tube. When a new fuel assembly 4 is released, it moves with the flow of the reactor coolant passing all hydraulic nozzles 12 not producing small jets until it reaches the hydraulic nozzle 12 producing a small jet directing the fuel assembly 4 toward the predetermined pressure tube 2. At that place, the fuel assembly 4 leaves the fuel assembly distribution header 10 and moves toward the pressure tube 2 inlet. To ensure that the fuel assembly does not enter another pressure tube (not predetermined), the fuel assembly distribution header 10 is slightly curved (not shown).
Subsequently, the fuel assembly 4 moves rollably in the fuel assembly distribution header being in contact with the header internal side opposite to the pipe branch leading to the pressure tube inlet. This modification requires significantly less hydraulic cylinders.
Referring to FIG. 4 of the drawings, a fuel assembly has a shell 5 having an exterior rolling surface by having a circular external axial cross-section and being of spherical or close to spherical form. The shell 5 has a plurality of holes 7 for circulation of the reactor coolant. Fuel elements 6 in the form of rods are positioned radially in all directions from the centre of the shell 5 (Fig. 4 shows only the first row of the fuel elements).
Referring to FIG. 5 of the drawings, a fuel assembly has a shell 5 having an exterior rolling surface. The shell 5 has a plurality of holes 7 for circulation of the reactor coolant. Spherical (or quasi-spherical) fuel elements 13 are positioned in the internal zone of the shell 5.
Referring to FIG. 6 of the drawings, spherical (or quasi-spherical) fuel elements 13 comprise a nuclear fuel 14 covered by a metal cladding 15. The cladding 15 have attached metal pads 16 preventing direct contact between the fuel elements and therefore preventing overheating of the fuel elements in the points of contact.
Referring to FIG. 7 of the drawings, a part of the fuel assembly distribution header 10 is shown having stems 9 of the hydraulic cylinders 8 preventing the movement of two fuel assemblies 4 with the flow of the rector coolant. The stems 9 have the end of each stem split in two rods.
While providing on-power refueling, this newly developed reactor completely eliminates the pressure tube plugs (in the range of 1000 per reactor), fuelling machine trolleys, fuelling ducts, fuelling heads, thus eliminating potential leaks of the reactor coolant, reducing the size of the reactor building, simplifying operations, maintenance, and greatly reducing the capital and O&M cost of the fuel handling equipment.
Several preferred embodiments of the present invention have been shown and described. However, it is apparent to those skilled in the art that many changes and modifications may be made without departing from the invention as it is defined in the appended claims.
TECHNICAL FIELD OF INVENTION
The present invention relates to nuclear reactors. More specifically, the present invention relates to pressurized fuel channel type reactors, for example, the water-cooled reactors, including pressurized water reactors (PWR) and pressurized heavy water reactors (PHWR), and, specifically, CANDU reactors for nuclear power plants.
BACKGROUND OF THE INVENTION AND PRIOR ART
Pressurized fuel channel type reactors are well known. A pressurized fuel channel type reactor (a reactor in the following text) comprises a group of fuel channels. A fuel channel comprises a horizontal or vertical pressure tube positioned in a moderator and containing fuel assemblies (fuel bundles). The reactor also comprises a reactor coolant circulation system comprising a group of pumps and providing circulation of the reactor coolant through the fuel channels, and a fuel handling apparatus (fuelling machine) for insertion of fuel assemblies into the pressure tubes and removal of fuel assemblies from the pressure tubes.
A reactor coolant is usually represented by light water, heavy water (in latter case a reactor is also known as a pressurized heavy water reactor (PHWR), represented by CANDU reactors), but there are many other coolants potentially available (liquid metal, molten salts, etc.). A reactor coolant circuit consists of a reactor, a heat consumer (usually a primary side of boilers in case of nuclear power plant), and reactor coolant pumps. The reactor coolant is pumped between fuel elements of fuel assemblies located in the fuel channels absorbing the heat generated by fuel elements and usually through the tube side of boilers of the nuclear power plant releasing the heat. The coolant further returns to the reactor coolant pump and to the reactor channels. The fuel handling apparatus (fuelling machine) consists of trolleys, fuelling heads comprising various mechanical and hydraulic devices to attach the fuelling heads to the both ends of the pre-selected pressure tube, remove and re-install the pressure tube plugs, insert a new fuel assembly into the pressure tube and remove the spent fuel assembly from another end of the pressure tube, a magazine containing the fuel assemblies, a heat exchanger and a circulation pump for cooling the removed fuel assemblies, control and instrumentation.
The pressurized fuel channel type reactors are described in the following patent applications or patents granted in Canada:
1066434 Isaac, Peter 2283647 Sollychin, Rayman The patent No. 2283647 that discloses a pressurized fuel channel type reactor having fuel channels, containing fuel assemblies (fuel bundles) aligned in pairs to reduce a hydraulic resistance of the fuel channel.
The closest prior art is the patent No. 1066434 discloses a pressurized fuel channel type reactor having horizontally extending fuel channels, a reactor coolant circulation system, and a fuel handling apparatus (fuelling machine) for insertion and removal of fuel assemblies into and from the fuel. The fuel handling apparatus comprises piston members assisting the process of fuel removal during on-line refueling.
The prior art does not sufficiently address an issue of on-line refueling that requires opening both the upstream and the downstream ends of the fuel channel filled with high temperature reactor coolant being under high pressure (10 MPa or higher). This operation is performed by a very complex and expensive fuelling machine. Any malfunction of the fuelling machine results in a forced shut down of the reactor and associated losses in generation in the range of $ 1,000,000 per day. There is also a potential for a loss of reactor coolant in the form of minor leaks from the connection points or even a complete loss of the reactor coolant in case of failure of the fuelling head to re-install correctly the pressure tube plug.
In addition, the prior art does not address high operation and maintenance (O&M) expenses and very high cost of the fuelling machine (fuel handling apparatus). The fuelling machine maintenance is further complicated by high radiation fields it is exposed to during on-line refueling thus making all the parts of the fuelling machine highly radioactive.
SUMMARY OF THE INVENTION
The present application develops the prior art to simplify the process of fuelling of the reactor. A pressurized fuel channel type reactor (a reactor in the following text) comprises a group of fuel channels. A fuel channel comprises a horizontal or vertical pressure tube positioned in a moderator and containing fuel assemblies (fuel bundles). The reactor also comprises a reactor coolant circulation system comprising a group of pumps and providing circulation of the reactor coolant through the fuel channels. A reactor coolant can be represented by light water or heavy water, but there are many other coolants potentially available (liquid metal, molten salts, etc.). A reactor coolant circuit consists of a reactor, a heat consumer (usually a primary side of boilers in case of nuclear power plant), and reactor coolant pumps. The reactor coolant is pumped between fuel elements of fuel assemblies located in the fuel channels absorbing the heat generated by fuel elements and usually through the tube side of boilers of the nuclear power plant releasing the heat. The coolant further returns to the reactor coolant pump and to the reactor channels. Fuel assembly has a capability of moving rollably in the pressure tubes and in pipes with the flow of the reactor coolant, for example, by having a spherical shape. A fuel assembly distribution header is connected to the pressure tube inlets and has a plurality of hydraulic cylinders controlling movement of fuel assemblies from fuel assembly distribution header into the pressure tube inlets. Functions of the part of the hydraulic cylinders can be performed by nozzles, connected to the source of the high-pressure reactor coolant and producing small jets of the reactor coolant directing each fuel assembly into the predetermined pressure tube. A fuel assembly collection header is connected to pressure tube outlets and has a plurality of hydraulic cylinders controlling the movement of fuel assemblies from the pressure tube outlets into the fuel assembly distribution header. This newly developed reactor completely eliminates the pressure tube plugs (in the range of 1000 per reactor), fuelling machine trolleys, fuelling heads, thus eliminating potential leaks of the reactor coolant, simplifying operations, maintenance, and greatly reducing the capital and O&M cost of the fuel handling.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of the pressurized fuel channel type nuclear reactor having horizontal fuel channels and individual fuel supply and removal pipes equipped with hydraulic cylinders controlling the movement of the fuel assemblies according to one embodiment of the present invention and corresponding to the claims 1, 2, 3, 4, 6, 7.
FIG. 2 is a schematic representation of the pressurized fuel channel type nuclear reactor having horizontal fuel channels, a fuel assembly distribution header, and a fuel assembly collection header, equipped with hydraulic cylinders controlling the movement of the fuel assemblies according to the embodiment of the present invention and corresponding to the claims 1, 2, 3, 4, 6, 7, 8, and 9.
FIG. 3 is a schematic representation of the pressurized fuel channel type nuclear reactor having horizontal fuel channels, a fuel assembly distribution header, and a fuel assembly collection header, equipped with hydraulic cylinders controlling the movement of the fuel assemblies according to the embodiment of the present invention and corresponding to the claims 1, 2, 3, 4, 6, 7, 9, and 10.
FIG. 4 is a schematic representation of a fuel assembly having a capability of moving rollably in the pressure tubes and in the pipes of the fuel handling apparatus according to the embodiment of the present invention and corresponding to the claims 1, 2, 3, 4, and 5. The fuel assembly comprises cylindrical fuel elements positioned radially within a spherical shell having a plurality of holes for circulation of the reactor coolant.
FIG. 5 is a schematic representation of a fuel assembly having a capability of moving rollably in the pressure tubes and in the pipes of the fuel handling apparatus according to the embodiment of the present invention and corresponding to the claims 1, 2, 3, 4, and 5. The fuel assembly comprises spherical fuel elements positioned within a spherical shell having a plurality of holes for circulation of the reactor coolant.
FIG. 6 is a schematic representation of a spherical fuel element.
FIG. 7 is a schematic representation of a part of the fuel assembly distribution header with two fuel assemblies shown. The movement of the fuel assemblies along the header is restricted by stems being a part of the hydraulic cylinder assembly (not shown).
Parts that are not essential to the invention and well known in power generation industry, such as details of the moderator design, end fittings, reactor coolant circulation system, boilers, control and instrumentation equipment, etc., are not shown.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1 of the drawings, a pressurized fuel channel type reactor (a reactor in the following text) comprises a group of fuel channels positioned in a moderator 1. A fuel channel comprises a horizontal pressure tube 2 (as shown) positioned inside the calandria tube 3 providing a thermal insulation layer between the pressure tube and the moderator. A vertical pressure tube arrangement is not shown. The pressure tubes contain fuel assemblies (fuel bundles). The reactor also comprises a reactor coolant circulation system comprising a group of pumps (not shown) and providing circulation of the reactor coolant through the fuel channels. A reactor coolant can be represented by light water or heavy water, but there are many other coolants potentially available (liquid metal, molten salts, etc.). A reactor coolant circuit consists of a reactor, a heat consumer (usually a primary side of boilers in case of nuclear power plant), and reactor coolant pumps. The reactor coolant is pumped between fuel elements of fuel assemblies located in the fuel channels absorbing the heat generated by fuel elements and usually through the tube side of boilers of the nuclear power plant releasing the heat. The coolant further returns to the reactor coolant pump and to the reactor channels.
A hydraulic cylinder is a device comprising a cylindrical hollow body with a piston.
The piston has an ability to move inside the cylinder along its axis depending on a pressure difference applied to the opposite piston surfaces. The stem (rod) is attached to the piston in the axial direction and moves with it. The hydraulic cylinder is attached (welded) to the fuel handling apparatus pipe and, depending on its position, either prevents or allows the movement of the fuel assembly with the flow of the reactor coolant.
Fuel assembly has a capability of moving rollably in the pressure tubes and in pipes with the flow of the reactor coolant by having a spherical or close to spherical shape. Each pressure tube 2 has two connections to the reactor coolant circulation system. Inlet of the pressure tube 2 is connected to the pipe of the fuel handling apparatus supplying new fuel assemblies 4. The pipe of the fuel handling apparatus is connected to the reactor coolant circulation system having an equal or higher pressure than the pressure of the reactor coolant at the inlet of the pressure tube 2 (not shown). The pipe of the fuel handling apparatus has two hydraulic cylinders 8, each of them having a piston and attached stem that moves into the pipe of the fuel handling apparatus controlling the movement of the fuel assemblies with the flow of the reactor coolant. The piston moves along the axis inside the cylindrical vessel to and from the pipe of the fuel handling apparatus depending on the pressure difference on opposite sides of the piston generated by external source of pressure (not shown). The stem can be of any form (shape) including being an elongated concave plate having passages for the reactor coolant (not shown), or having the end of the stem split in two rods as shown on Fig. 7.
To remove one used fuel assembly from the pressure tube 2, the stem 9 of the right (as seen on Fig.1) of two hydraulic cylinders 8, located downstream of the outlet of the pressure tube 2, retracts, and the first fuel assembly 4 moves rollably with the flow from the outlet of the pressure tube 2 and stops when it reaches the used fuel storage location outside the reactor (not shown). After that, the stem 9 returns to previous position (extends into the pipe).
Similarly, when the stem 9 of the left (as seen on Fig.1) of two hydraulic cylinders 8, located at the outlet of the pressure tube 2, retracts, all fuel assemblies positioned upstream of the stem inside the pressure tube 2 move rollably with the reactor coolant flow toward the outlet of the pressure tube 2 until the first of them reaches the extended stem 9 of the right hydraulic cylinder 8.
To insert one new fuel assembly into the pressure tube 2, the stem 9 of the lower (as seen on Fig.1) of two hydraulic cylinders 8, located upstream of the inlet of the pressure tube 2, retracts, one new fuel assembly 4 moves rollably with the flow toward the inlet of the pressure tube 2 and stops when it reaches the first (from the left side) fuel assembly positioned in the pressure tube 2. After that, the stem 9 returns to previous position (extends into the pipe). Similarly, when the stem 9 of the upper (as seen on Fig.1) of two hydraulic cylinders 8 retracts, all new fuel assemblies positioned upstream of the stem move rollably with the reactor coolant flow toward the inlet of the pressure tube 2 until the first of them reaches the extended stem 9 of the lower hydraulic cylinder 8.
Referring to FIG. 2 of the drawings, a pressurized fuel channel type reactor is provided with a fuel assembly distribution header 10 (a pipe) connected to the group of the pressure tube 2 inlets and has two hydraulic cylinders 8 controlling a movement of the fuel assemblies 4 into the fuel assembly distribution header 10, and a plurality of hydraulic cylinders 8, each of them controlling movement of fuel assemblies 4 from fuel assembly distribution header into each pressure tube 2 inlet of the group. When a new fuel assembly 4 is released, it moves with the flow of the reactor coolant passing all hydraulic cylinders 8 having their stems 9 retracted until it reaches the hydraulic cylinder having its stem 9 extended directing the fuel assembly 4 toward the predetermined pressure tube 2. At that place, the fuel assembly 4 leaves the fuel assembly distribution header 10 and moves toward the pressure tube 2 inlet. To ensure that the fuel assembly does not enter another pressure tube (not predetermined), the fuel assembly distribution header 10 is slightly curved (not shown). Subsequently, the fuel assembly moves rollably in the fuel assembly distribution header being in contact with the header internal side opposite to the pipe branch leading to the pressure tube 2 inlet. This modification requires significantly less hydraulic cylinders.
The reactor is also provided with a fuel assembly collection header 11 (a pipe) connected to the group of the pressure tube outlets. Two hydraulic cylinders 8 control the movement of the fuel assemblies 4 from each of the pressure tubes into the fuel assembly collection header 11.
Referring to FIG. 3 of the drawings, a pressurized fuel channel type reactor is provided with a fuel assembly distribution header 10 (a pipe) connected to the group of the pressure tube inlets and has two hydraulic cylinders 8 controlling a movement of the fuel assemblies 4 into the fuel assembly distribution header 10, and a plurality of hydraulic nozzles 12, each of them controlling movement of fuel assemblies 4 from the fuel assembly distribution header 10 into each pressure tube inlet of the group. Functions of the part of the hydraulic cylinders are performed by nozzles 12, connected to the source of the high-pressure reactor coolant and producing small jets of the reactor coolant directing each fuel assembly into the predetermined pressure tube. When a new fuel assembly 4 is released, it moves with the flow of the reactor coolant passing all hydraulic nozzles 12 not producing small jets until it reaches the hydraulic nozzle 12 producing a small jet directing the fuel assembly 4 toward the predetermined pressure tube 2. At that place, the fuel assembly 4 leaves the fuel assembly distribution header 10 and moves toward the pressure tube 2 inlet. To ensure that the fuel assembly does not enter another pressure tube (not predetermined), the fuel assembly distribution header 10 is slightly curved (not shown).
Subsequently, the fuel assembly 4 moves rollably in the fuel assembly distribution header being in contact with the header internal side opposite to the pipe branch leading to the pressure tube inlet. This modification requires significantly less hydraulic cylinders.
Referring to FIG. 4 of the drawings, a fuel assembly has a shell 5 having an exterior rolling surface by having a circular external axial cross-section and being of spherical or close to spherical form. The shell 5 has a plurality of holes 7 for circulation of the reactor coolant. Fuel elements 6 in the form of rods are positioned radially in all directions from the centre of the shell 5 (Fig. 4 shows only the first row of the fuel elements).
Referring to FIG. 5 of the drawings, a fuel assembly has a shell 5 having an exterior rolling surface. The shell 5 has a plurality of holes 7 for circulation of the reactor coolant. Spherical (or quasi-spherical) fuel elements 13 are positioned in the internal zone of the shell 5.
Referring to FIG. 6 of the drawings, spherical (or quasi-spherical) fuel elements 13 comprise a nuclear fuel 14 covered by a metal cladding 15. The cladding 15 have attached metal pads 16 preventing direct contact between the fuel elements and therefore preventing overheating of the fuel elements in the points of contact.
Referring to FIG. 7 of the drawings, a part of the fuel assembly distribution header 10 is shown having stems 9 of the hydraulic cylinders 8 preventing the movement of two fuel assemblies 4 with the flow of the rector coolant. The stems 9 have the end of each stem split in two rods.
While providing on-power refueling, this newly developed reactor completely eliminates the pressure tube plugs (in the range of 1000 per reactor), fuelling machine trolleys, fuelling ducts, fuelling heads, thus eliminating potential leaks of the reactor coolant, reducing the size of the reactor building, simplifying operations, maintenance, and greatly reducing the capital and O&M cost of the fuel handling equipment.
Several preferred embodiments of the present invention have been shown and described. However, it is apparent to those skilled in the art that many changes and modifications may be made without departing from the invention as it is defined in the appended claims.
Claims (10)
1. A pressurized fuel channel type nuclear reactor comprising:
- a plurality of pressure tubes, wherein each of said pressure tubes having a pressure tube inlet and a pressure tube outlet and being filled with a reactor coolant;
- a plurality of fuel assemblies, wherein each of said fuel assemblies comprising fuel elements and positioned in said pressure tubes;
- a reactor coolant circulation system comprising a pump being in flow communication with said pressure tubes and providing circulation of the reactor coolant through said pressure tubes;
- a fuel handling apparatus for insertion of fuel assemblies into the pressure tubes and removal of fuel assemblies from the pressure tubes, wherein said fuel handling apparatus comprising pipes being in flow communication with said pressure tubes and being filled with the reactor coolant;
wherein each said fuel assembly having a capability of moving rollably in said pressure tubes and in said pipes of said fuel handling apparatus.
- a plurality of pressure tubes, wherein each of said pressure tubes having a pressure tube inlet and a pressure tube outlet and being filled with a reactor coolant;
- a plurality of fuel assemblies, wherein each of said fuel assemblies comprising fuel elements and positioned in said pressure tubes;
- a reactor coolant circulation system comprising a pump being in flow communication with said pressure tubes and providing circulation of the reactor coolant through said pressure tubes;
- a fuel handling apparatus for insertion of fuel assemblies into the pressure tubes and removal of fuel assemblies from the pressure tubes, wherein said fuel handling apparatus comprising pipes being in flow communication with said pressure tubes and being filled with the reactor coolant;
wherein each said fuel assembly having a capability of moving rollably in said pressure tubes and in said pipes of said fuel handling apparatus.
2. The pressurized fuel channel type nuclear reactor of claim 1, wherein said fuel assembly having an exterior rolling surface defining an internal zone wherein said fuel elements positioned in said internal zone.
3. The pressurized fuel channel type nuclear reactor of claim 2, wherein said fuel assembly having a circular external axial cross-section.
4. The pressurized fuel channel type nuclear reactor of claim 2, wherein said exterior rolling surface of said fuel assembly being a part of an exterior surface of a sphere.
5. The pressurized fuel channel type nuclear reactor of claim 2, wherein said exterior rolling surface of said fuel assembly having a plurality of holes for circulation of the reactor coolant through said internal zone of said fuel assembly.
6. The pressurized fuel channel type nuclear reactor of claim 1, wherein said fuel handling apparatus comprising a means to insert said fuel assembly into said reactor coolant circulation system upstream of said pressure tube.
7. The pressurized fuel channel type nuclear reactor of claim 1, wherein said fuel handling apparatus comprising a means to remove said fuel assembly downstream of said pressure tube.
8. The pressurized fuel channel type nuclear reactor of claim 6, wherein said means to insert said fuel assembly into said reactor coolant circulation system comprise a fuel assembly distribution header being in flow communication with said pressure tube inlet and a plurality of hydraulic cylinders controlling movement of fuel assemblies from said fuel assembly distribution header into said pressure tube inlet.
9. The pressurized fuel channel type nuclear reactor of claim 7, wherein said means to remove said fuel assembly downstream of said pressure tube comprise a fuel assembly collection header being in flow communication with said pressure tube outlet and a plurality of hydraulic cylinders controlling movement of fuel assemblies from said pressure tube outlet into said fuel assembly collection header.
10. The pressurized fuel channel type nuclear reactor of claim 6, wherein said means to insert said fuel assembly into said reactor coolant circulation system comprise a fuel assembly distribution header being in flow communication with said pressure tube inlet and a plurality of nozzles being in flow communication with a source of the reactor coolant having a higher pressure than the reactor coolant pressure in said distribution header and strategically positioned to control the movement of fuel assembly from said fuel assembly distribution header into said pressure tube inlet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002622547A CA2622547A1 (en) | 2008-02-28 | 2008-02-28 | Pressurized fuel channel type nuclear reactor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002622547A CA2622547A1 (en) | 2008-02-28 | 2008-02-28 | Pressurized fuel channel type nuclear reactor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2622547A1 true CA2622547A1 (en) | 2009-08-28 |
Family
ID=41010623
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002622547A Abandoned CA2622547A1 (en) | 2008-02-28 | 2008-02-28 | Pressurized fuel channel type nuclear reactor |
Country Status (1)
| Country | Link |
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| CA (1) | CA2622547A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015166203A1 (en) * | 2014-04-29 | 2015-11-05 | Ian Richard Scott | Movement of fuel tubes within an array |
| GB2545030A (en) * | 2015-12-06 | 2017-06-07 | Richard Scott Ian | Rectangular nuclear reactor core |
| WO2017098228A1 (en) * | 2015-12-06 | 2017-06-15 | Ian Richard Scott | Rectangular nuclear reactor core |
| CN112735614A (en) * | 2020-12-11 | 2021-04-30 | 中核核电运行管理有限公司 | Quality control device and method for full-reactor fuel channel medium-term overhaul of heavy water reactor nuclear power station |
-
2008
- 2008-02-28 CA CA002622547A patent/CA2622547A1/en not_active Abandoned
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015166203A1 (en) * | 2014-04-29 | 2015-11-05 | Ian Richard Scott | Movement of fuel tubes within an array |
| CN106463184A (en) * | 2014-04-29 | 2017-02-22 | 伊恩·理查德·斯科特 | Movement of fuel tubes within array |
| CN106463184B (en) * | 2014-04-29 | 2018-04-27 | 伊恩·理查德·斯科特 | The movement of cartridge in array |
| GB2545030A (en) * | 2015-12-06 | 2017-06-07 | Richard Scott Ian | Rectangular nuclear reactor core |
| WO2017098228A1 (en) * | 2015-12-06 | 2017-06-15 | Ian Richard Scott | Rectangular nuclear reactor core |
| KR20180083438A (en) * | 2015-12-06 | 2018-07-20 | 이안 리차드 스코트 | Rectangular reactor core |
| KR101968617B1 (en) | 2015-12-06 | 2019-04-12 | 이안 리차드 스코트 | Rectangular reactor core |
| CN112735614A (en) * | 2020-12-11 | 2021-04-30 | 中核核电运行管理有限公司 | Quality control device and method for full-reactor fuel channel medium-term overhaul of heavy water reactor nuclear power station |
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