CA2380909A1 - Differential pressure based lock - Google Patents
Differential pressure based lock Download PDFInfo
- Publication number
- CA2380909A1 CA2380909A1 CA002380909A CA2380909A CA2380909A1 CA 2380909 A1 CA2380909 A1 CA 2380909A1 CA 002380909 A CA002380909 A CA 002380909A CA 2380909 A CA2380909 A CA 2380909A CA 2380909 A1 CA2380909 A1 CA 2380909A1
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- Canada
- Prior art keywords
- pressure
- pressure vessel
- snout
- lock
- connecting mechanism
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- 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
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- 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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L37/00—Couplings of the quick-acting type
- F16L37/08—Couplings of the quick-acting type in which the connection between abutting or axially overlapping ends is maintained by locking members
- F16L37/084—Couplings of the quick-acting type in which the connection between abutting or axially overlapping ends is maintained by locking members combined with automatic locking
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C13/00—Details of vessels or of the filling or discharging of vessels
-
- 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
- G21C19/22—Arrangements for obtaining access to the interior of a pressure vessel whilst the reactor is operating
- G21C19/24—Arrangements for obtaining access to the interior of a pressure vessel whilst the reactor is operating by using an auxiliary vessel which is temporarily sealed to the pressure vessel
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- 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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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- High Energy & Nuclear Physics (AREA)
- Mechanical Engineering (AREA)
- Monitoring And Testing Of Nuclear Reactors (AREA)
Abstract
A lock for securing the head of a fuelling machine, defuelling machine or inspection machine to the end fitting of a fuel channel of a nuclear reactor is a rod and piston lock which engages or disengages according to the differential between the pressure in the snout cavity and the pressure in the fuelling machine magazine. The lock is engaged when the snout cavity pressure and the fuelling machine pressure are substantially equalized. When the pressure in the snout cavity is reduced sufficiently below the level of the pressure in the fuelling machine, the lock is engaged. The lock remains engaged if there is a drop in reactor pressure during refuelling and during reactor shutdown conditions. Engagement of the lock prevents inadvertent unclamping of the fuelling machine from the fuel channel.
Description
DIFFERENTIAL PRESSURE BASED LOCK
FIELD OF THE INVENTION
This invention relates to a differential pressure based lock. More specifically, the invention is a lock for securing two pressure vessels together. It has particular application in securing a fuelling machine, defuelling machine or inspection machine to the fuel channel of a nuclear reactor.
BACKGROUND OF THE INVENTION
A pressurized fuel channel type nuclear reactor, such as the CANDU°
nuclear reactor, is comprised of a pressure vessel containing horizontally oriented fuel channels.
A typical reactor contains approximately 400 fuel channels. 'The fuel channels are themselves also pressure vessels. Each fuel channel contains a plurality of fuel bundles longitudinally disposed in end-to-~end relation within a pressure tube. Each fuel bundle comprises a plurality of elongated fuel rods containing fissionable material. High pressure heavy or light water coolant flows through the fuel channels to cool the fuel rods and remove heat produced by the fission process. Each end of each fuel channel has an end fitting to contain the contents of, and provide the interfaces to, the fuel channel.
Refuelling of the reactor is carried out with a fuelling machine to remove the spent fuel bundles and insert fresh replacement fuel bundles. The head of the fuelling machine is also a pressure vessel. Fuel bundles are loaded into a fuel transfer mechanism and then pushed into the fuelling machine head's fuel loading magazine. The fuel bundles are loaded into the fuel channel through the snout of the fuelling machine head. When refuelling is to take place, the fuelling machine is remotely moved to the reactor face and the snout of the fuelling machine head is clamped to the end fitting of a fuel channel. A snout clamping mechanism, operated by a snout drive assembly, clamps the snout to the end fitting. The fuelling machine closure and the fuel channel closure are then removed so that the fuel channel is open to the fuelling machine.
FIELD OF THE INVENTION
This invention relates to a differential pressure based lock. More specifically, the invention is a lock for securing two pressure vessels together. It has particular application in securing a fuelling machine, defuelling machine or inspection machine to the fuel channel of a nuclear reactor.
BACKGROUND OF THE INVENTION
A pressurized fuel channel type nuclear reactor, such as the CANDU°
nuclear reactor, is comprised of a pressure vessel containing horizontally oriented fuel channels.
A typical reactor contains approximately 400 fuel channels. 'The fuel channels are themselves also pressure vessels. Each fuel channel contains a plurality of fuel bundles longitudinally disposed in end-to-~end relation within a pressure tube. Each fuel bundle comprises a plurality of elongated fuel rods containing fissionable material. High pressure heavy or light water coolant flows through the fuel channels to cool the fuel rods and remove heat produced by the fission process. Each end of each fuel channel has an end fitting to contain the contents of, and provide the interfaces to, the fuel channel.
Refuelling of the reactor is carried out with a fuelling machine to remove the spent fuel bundles and insert fresh replacement fuel bundles. The head of the fuelling machine is also a pressure vessel. Fuel bundles are loaded into a fuel transfer mechanism and then pushed into the fuelling machine head's fuel loading magazine. The fuel bundles are loaded into the fuel channel through the snout of the fuelling machine head. When refuelling is to take place, the fuelling machine is remotely moved to the reactor face and the snout of the fuelling machine head is clamped to the end fitting of a fuel channel. A snout clamping mechanism, operated by a snout drive assembly, clamps the snout to the end fitting. The fuelling machine closure and the fuel channel closure are then removed so that the fuel channel is open to the fuelling machine.
To avoid the remote possibility of a fuel spill of whole or partial fuel bundles from the fuel channel or the leak of reactor coolant, it is important that the fuel channel not become disconnected from the fuelling machine while either the fuelling machine closure or the fuel channel closure is removed. The snout clamping mechanism and the snout drive assembly are designed and tested to ensure that the seal between the end fitting and the snout is well maintained unless commanded to unclamp. However, it is possible that under certain conditions of temperature or vibration, the snout drive assembly may back-drive. For example, such conditions may potentially occur as a result of a seismic event. In addition, it is possible that the snout drive assembly is commanded to unclamp at the wrong time as a result of operator error, system error, or a system fault such as an electrical short.
To avoid any such inadvertent unclamping, the snout drive assembly is provided with a mechanical lock that acts to immobilize the snout drive assembly and thereby prevent actuation of the clamping mechanism. In addition, electrical and software interlocks are commonly used to prevent the snout drive assembly from being operated.
One of the commonly used mechanical locks is a rod and piston type lock which engages when the end of the rod, acting as a lock pin, protrudes into a recess in the snout drive assembly.
During refuelling, the snout cavity is open to the reactor operating pressure.
The pressure in the snout cavity activates the piston to drive the lock pin into place in the snout drive. This compresses a large spring on the rod side of the piston. Once refuelling is complete, the snout cavity is depressurized. When the pressure in the snout cavity falls below a pre-set level, the apring re-extends, the lock pin withdraws and the lock disengages. Thus, the lock is activated by 'the pressure from the reactor and de-activated by re-extension of the spring.
The spring release must be powerful enough to disengage the lock when lubricants degrade or seals tear, and .accordingly, the disengage pressure level is set relatively high.
Although the rod and piston type lock operates effectively and reliably, it does not immobilize the snout drive assembly to prevent unclamping of the fuelling machine from the fuel channel if the reactor pressure falls below the disengage pressure level.
Thus, if there were a reduction in pressure in the reactor caused by a loss of coolant accident, a main steam line break or other such upset or accident condition, the lock would disengage and there would be a risk that the snout and the end fitting would become disconnected, resulting in a possible reactor coolant leak or nuclear fuel spill.
Another scenario in which the rod and piston type lock does not act to secure the connection between the fuel channel and the fuelling machine is during shutdown conditions.
Although refuelling of the fuel channels generally takes place when the reactor is online, it may be carried out while the reactor is in shutdown mode. The pressure in the fuel channels during shutdown mode is reduced to about 50 psi. This pressure level is insufficient to cause the rod and piston type lock to engage and, accordingly, the lock is non-operational during shutdown conditions.
Many attempts have been made to develop a lock which overcomes the deficiencies of the aforementioned rod and piston type lock. For example, the assignee of the present application developed a lock which would operate over a greater pressure range. The lock presented operational difficulties as a result of the greater pressure range.
For instance, during leak checks carried out during the refuelling process, and in other circumstances, pressurization in the snout cavity caused the lock to partially engage at the time that the fuelling machine was to be removed from the reactor face. In addition, the larger piston which this lock required made it difficult to manufacture to a size package that could be retrofitted.
Thus, there is a need for a lock which effectively inactivates the snout drive assembly thereby securing the connection between the fuel channel and the fuelling machine, and which remains operational in the event of a reduction or loss of pressure in the fuel channel and during reactor shutdown conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of the fuel chaimel end fitting connected to the fuelling machine snout with the lock of the present invention in situ.
FIG. 2 is a cross-sectional view of the lock of the present invention in its disengaged position.
1FIG. 3 is a cross-sectional view of the Lock of the present invention in its engaged position.
To avoid any such inadvertent unclamping, the snout drive assembly is provided with a mechanical lock that acts to immobilize the snout drive assembly and thereby prevent actuation of the clamping mechanism. In addition, electrical and software interlocks are commonly used to prevent the snout drive assembly from being operated.
One of the commonly used mechanical locks is a rod and piston type lock which engages when the end of the rod, acting as a lock pin, protrudes into a recess in the snout drive assembly.
During refuelling, the snout cavity is open to the reactor operating pressure.
The pressure in the snout cavity activates the piston to drive the lock pin into place in the snout drive. This compresses a large spring on the rod side of the piston. Once refuelling is complete, the snout cavity is depressurized. When the pressure in the snout cavity falls below a pre-set level, the apring re-extends, the lock pin withdraws and the lock disengages. Thus, the lock is activated by 'the pressure from the reactor and de-activated by re-extension of the spring.
The spring release must be powerful enough to disengage the lock when lubricants degrade or seals tear, and .accordingly, the disengage pressure level is set relatively high.
Although the rod and piston type lock operates effectively and reliably, it does not immobilize the snout drive assembly to prevent unclamping of the fuelling machine from the fuel channel if the reactor pressure falls below the disengage pressure level.
Thus, if there were a reduction in pressure in the reactor caused by a loss of coolant accident, a main steam line break or other such upset or accident condition, the lock would disengage and there would be a risk that the snout and the end fitting would become disconnected, resulting in a possible reactor coolant leak or nuclear fuel spill.
Another scenario in which the rod and piston type lock does not act to secure the connection between the fuel channel and the fuelling machine is during shutdown conditions.
Although refuelling of the fuel channels generally takes place when the reactor is online, it may be carried out while the reactor is in shutdown mode. The pressure in the fuel channels during shutdown mode is reduced to about 50 psi. This pressure level is insufficient to cause the rod and piston type lock to engage and, accordingly, the lock is non-operational during shutdown conditions.
Many attempts have been made to develop a lock which overcomes the deficiencies of the aforementioned rod and piston type lock. For example, the assignee of the present application developed a lock which would operate over a greater pressure range. The lock presented operational difficulties as a result of the greater pressure range.
For instance, during leak checks carried out during the refuelling process, and in other circumstances, pressurization in the snout cavity caused the lock to partially engage at the time that the fuelling machine was to be removed from the reactor face. In addition, the larger piston which this lock required made it difficult to manufacture to a size package that could be retrofitted.
Thus, there is a need for a lock which effectively inactivates the snout drive assembly thereby securing the connection between the fuel channel and the fuelling machine, and which remains operational in the event of a reduction or loss of pressure in the fuel channel and during reactor shutdown conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of the fuel chaimel end fitting connected to the fuelling machine snout with the lock of the present invention in situ.
FIG. 2 is a cross-sectional view of the lock of the present invention in its disengaged position.
1FIG. 3 is a cross-sectional view of the Lock of the present invention in its engaged position.
SUMMARY OF THE INVENTION
The lock of the present invention acts to prevent inadvertent unclamping of the fuelling machine from the fuel channel in conditions in which the prior art locks do not. The action of the lock is based on the differential pressure between the snout cavity and the fuelling machine magazine. The lock is engaged when the snout cavity pressure and the fuelling machine pressure are substantially equalized. This occurs before the snout and fuel channel closures are removed. Thus, the lock remains engaged if there is a drop in reactor pressure during refuelling and the lock is also operational during reactor shutdown conditions when the reactor pressure is substantially reduced. Once refuelling is complete and the closures are replaced, the snout cavity pressure is vented and the fuelling machine magazine pressure acts to disengage the lock. Thus, the lock remains engaged if there is a drop in reactor pressure during refuelling. The lock is also operational during reactor shutdown conditions when the reactor pressure is substantially reduced.
Thus in accordance with the present invention, there is provided a means for locking a connecting mechanism, said connecting mechanism adapted to sealingly engage a first pressure vessel and a second pressure vessel at an interconnecting passageway, comprising: closure means in said passageway effective to maintain a pressure differential between said first and second pressure vessels; means for pressurizing said first pressure vessel to pressure of said second pressure vessel to eliminate said pressure differential and allow removal of said closure into the interior of said first pressure vessel permitting access to the interior of said second pressure vessel from said first pressure vessel; a rod and piston longitudinally movable within a hydraulic chamber between a first position effective to lock said connecting mechanism and a second position effective to unlock said connecting mechanism, the rod end of said chamber in fluid communication with the first pressure vessel side of said closure means and the piston end of said chamber in fluid communication with the second pressure vessel side of said closure means; wherein the elimination of said pressure differential is effective to move said rod and ;piston to said first position.
In accordance with another aspect of the present invention, there is provided a means for llocking a connecting mechanism, said connecting mechanism adapted to sealingly engage a first pressure vessel and a second pressure vessel at an interconnecting cavity in an interconnecting passageway, comprising: a first closure means in said passageway effective to maintain a first pressure differential between said first pressure vessel and said interconnecting cavity; a second closure means in said passageway effective to maintain a second pressure differential between said second pressure vessel and said interconnecting cavity; means for pressurizing said interconnecting cavity to pressure of said first pressure vessel to eliminate said first pressure differential and allow removal of said first closure means into interior of said first pressure vessel; means for depressurizing said interconnecting cavity to establish a pressure differential between said interconnecting cavity and said first pressure vessel; and a rod and piston longitudinally movable within a hydraulic chamber between a first position effective to lock said connecting mechanism and a second position effective to unlock said connecting mechanism, the rod end of said chamber in fluid communication with said first pressure vessel and the piston end of said chamber in fluid communication with said interconnecting cavity;
wherein the elimination of said pressure differential is effective to move said rod and piston to said first position and the establishment of said pressure differential is effective to move said rod and piston to said second position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The fuel channels of a CANDU~ reactor are refuelled by means of a remotely operated fuelling machine which removes spent fuel bundles from the fuel channel and replaces them with fresh fuel bundles. The spent fuel bundles and the fresh fuel bundles are stored in fuel ports in the fuelling machine. In order for the refuelling process to take place, the head of the fuelling machine is connected to the fuel channel in the manner illustrated in FIG. 1.
Fuel channel 10 is a longitudinal cylindrical assembly of approximately 4 inches in inside diameter and is adapted to contain a series of fuel bundles in end-to-end relation. High pressure heavy or light water coolant enters fuel channel 10 at one end, flows through the fuel bundles to cool the fuel rods .and remove heat produced by the fission process, and exits from fuel channel 10 at the opposite end. An end fitting, one of which is shown by reference numeral 12, is affixed to each end of fuel channel 10. Closure plugs, one of which is shown by reference numeral 14, are removable closures for fuel channel 10 which fit within the distal portion of each end fitting 12 and function to contain the contents of fuel channel 10. The pressure boundary for fuel channel 10 is at closure plug 14.
The fuelling machine head is a pressure vessel which contains a fuel loading mechanism.
Fuel loading magazine (a portion of which is shown at reference numeral 20) receives fuel into vacant positions for insertion into and removal from fuel channel 10. Snout 22 is a barrel-like extension of fuelling machine magazine 20 through which the fuel bundles pass to fuel channel 10. Fuelling machine snout plug 24 is a removable closure positioned within snout 22. The pressure boundary of fuelling machine is at snout plug 24.
A metallic seal between end fitting 12 and snout 22 is effected by clamp 26.
Clamp 26 consists of clamp jaws 28 on arm 30. Clamp jaws 28 are wedge elements which are pulled down into groove 32 on the outside of end fitting 12 to pull end fitting 12 and snout 22 tightly together.
A snout drive assembly drives clamp 26. In the embodiment illustrated in FIG.
l, the snout drive assembly is a screw-based linear actuator consisting of clamping barrel 34 on end fitting 12, ring gear 36 and gear rack 38. Gear rack 38 drives ring gear 36 which pulls barrel back towards fuelling machine and applies pressure to clamp 26 causing activation of jaws 28. Other types of snout drive assemblies may be used, for example, rack and pinion or sprag disc type assemblies.
When end fitting 12 and snout 22 are sealed, the volume surrounding the distal portion of snout plug 24 is contained and is referred to as snout cavity 16.
The lock of the present invention, illustrated by reference numeral 40 in FIG.
1 and shown in greater detail in FIGS. 2 and 3, acts on the snout drive assembly to prevent unclamping of end fitting 12 and snout 22. With reference to FIG. 2, lock has a rod and piston-type assembly housed by casing 42. Piston 44 and spring 46 occupy hydraulic piston chamber 48. Spring 46 is engaged to floor of piston chamber 48 and is biased to bottom of piston 44 such that when spring 46 is compressed, piston 44 is positioned in the lower part of piston chamber 48 and when spring 46 is extended, piston 44 is positioned in the upper part of piston chamber 48. Rod 52 extends from top of piston 44 through upper part of casing 42. Upper portion of rod 52 extends through ambushing 52 to potentially engage gear rack 38.
Rod seal 54 and piston seal 56 provide fluid seals for the rod 50 and piston 44, respectively. Seals 54, 56 may be O-rings, T-rings or any other suitable seal type. Rod 50 has lubricating means (not shown) and grease wiper seal 58. The piston and lock diameters can be -7_ any suitable dimension. In a lock used with a typical snout drive assembly, the piston diameter is about 2 inches, the rod diameter is about 1 inch and the load of the spring in its extended position is about 52 pounds.
Lock 40 is connected to fuelling machine magazine 20 and snout cavity 16 in the manner illustrated in FIG. 1. Snout connection tube 60 attaches to piston port 62 and connects snout cavity 16 to piston side of piston chamber 48 through piston channel 64.
Magazine connection tube 66 attaches to rod port 68 and connects fuelling machine magazine 20 to rod side of piston chamber 48 through rod channel 70. 'Tubes 60, 66 are connected to snout cavity 16 and fuelling machine magazine 20 in any suitable manner and preferably, for reasons of convenience, to pre existing pressure lines or ports.
A magnet rod 72 is mounted on a threaded rod screwed into piston 44 within tube 73.
Reed type magnetic switches 74 are mounted on the outside of tube 73 at fixed positions.
Switches 74 detect the location of the magnet allowing for remote sensing of the position of piston 44.
Drain port 76 has horizontal channel 78 to drain fluid if rod seal 54 fails and vertical channel 80 to drain any fluid that may have leaked into the snout drive mechanism.
To refuel a fuel channel, the fuelling machine head magazine 20 is moved to the reactor face and snout 22 is connected to end fitting 12 by clamp 26. Assuming that the reactor is in operating mode, the pressure in fuel channel 10 is at reactor operating pressure. The pressure in fuelling machine magazine 20 is at park pressure and the pressure in snout cavity 16 is at reactor lbuilding pressure. Park pressure is the pressure required to cool the spent fuel contained in the fuelling machine magazine 20. More specifically, it corresponds to the minimum pressure at the :fuelling machine head necessary to ensure coolant flows back through the cooling pipes which extend from the fuelling machine head. Once snout 22 and end fitting 12 have been clamped together, a leak check of snout cavity 16 is performed. Snout cavity 16 is pressurized to magazine park pressure through a line (not shown) which may be independent or may extend iErom a T-piece in line 60.
Once the pressures in snout cavity 16 and fuelling machine magazine 20 are equalized, a ram assembly withdraws the snout plug into the interior magazine of the fuelling machine. The _g_ pressure in the fuelling machine is then raised to reactor operating pressure.
A ram assembly withdraws closure plug 14 into the interior magazine of the fuelling machine once the pressures in fuel channel 10, snout cavity 16 and fuelling machine magazine 20 are equalized. Once refuelling of a fuel channel has been completed, the ram assembly replaces closure plug 14 and the pressure in the fuelling machine is reduced to fuelling machine park pressure. The ram assembly then replaces snout plug 24. Once snout cavity 16 has been vented to reactor building pressure, the snout drive assembly operates to disengage clamp 26 and the fuelling machine is then moved away from the reactor face.
When end fitting 12 is initially clamped to snout 22, the difference between the pressure in fuelling machine magazine 20 and the pressure in snout cavity 16 is sufficient to generate a large enough force in the rod side of piston chamber 48 to keep spring 48 compressed and rod 50 within bushing 54. In this state, lock 40 is in its disengaged position as illustrated in FIG. 2. As soon as the fuelling machine magazine and snout cavity pressures are equalized to allow removal of snout plug 24, as a result of the greater surface area of piston 44, the pressure in the piston side of piston chamber 48 together with spring 46 causes piston 44 to rise within piston chamber 48 and rod 50 to emerge from bushing 54 and overlap with a stop bracket affixed to the bottom of gear rack 38. Alternatively, the bottom of gear rack 38 may have a recess sized for a bolt-like insertion of rod 50. The engagement of rod 50 with gear rack 38 immobilizes the snout drive assembly such that clamp 26 cannot be released. In this state, lock 40 is in its engaged position.
Lock 40 remains engaged as the fuelling machine pressure is raised to reactor operating pressure and channel closure plug 14 is removed, and continues to remain engaged throughout the refuelling process. Once refuelling is complete and channel closure plug 14 and snout plug 24 have been replaced, snout cavity 16 is vented to reactor building pressure whereas fuelling machine magazine remains at park pressure. hock 40 disengages when a large enough positive fuelling machine magazine to snout cavity pressure differential exists. The fuelling machine magazine pressure connected to the rod side of piston chamber 48 drives piston 44 down and rod 50 to retract from the stops or recess in gear rack 38 in the snout mechanism drive.
Magazine connection tube 66 is preferably placed in front of snout connection tube 60 so that any mechanical damage to the tubes affects magazine connection tube 66 first. This ensures that lock 40 remains engaged in such circumstances.
There are numerous advantages to the present invention.
The lock engages at an earlier stage in the refuelling process and, more specifically, engages before the fuelling machine is online with the reactor.
In addition, if there is a reduction or loss of pressure in a fuel channel while it is open to the fuelling machine, the magazine to snout cavity pressure differential will not exist and the lock will remain engaged. Even if all pressure is lost in the magazine and snout cavity, the spring will act to keep the lock engaged. As a result, if a loss of coolant accident, a main steam line break or other such upset or accident conditions occur, the lock will remain engaged and ensure that the fuelling machine does not become disconnected from the fuel channel. Not only is there a greater risk of inadvertent unclamping during such conditions but it is also during such an event that it is of particular importance that the lock remain engaged because if the fuelling machine were to become disconnected from the fuel channel during upset or accident conditions, the severity of any leakage of reactor coolant or spillage of nuclear fuel would be greater.
Another advantage of the lock of the present invention over prior art locks is that it operates during reactor shutdown conditions. When a reactor is in shutdown mode, the reactor pressure is generally less than about 50 psi. Refuelling often continues when the reactor is in this mode. The procedure is the same as when the reactor is in operating mode and the relative pressure sequence is the same. Because the engagement and disengagement of the lock is dependent on the snout cavity to fuelling magazine differential, the lock engages once the magazine and snout cavity pressure have been equalized. The prior art locks were not operational during shutdown conditions.
A further advantage of the lock of the present invention is that it prevents the fuelling machine from being removed from a fuel port in the level lowered condition when the snout plug is removed. This condition arises when the fluid level in the fuelling magazine head is lowered to allow the fuel to be passed through air from the heavy water into light water. If the snout plug is not sealing adequately, the leak rate will be too high and the pressure in the snout cavity will increase causing the lock to engage. The fuelling machine can then stay in place and capture the leaks. The re-engagement of the lock also allows another attempt at inserting the plug with an improved seal. Removal of the fuelling machine from a fuel port without the snout plug in place creates the opportunity for tritium to be leaked from the snout and for air and gas to be entrained in the magazine coolant which will affect the pH and may cause oxidation and precipitation, as well as sloshing of D20.
The lock of the present invention provides a further operational safety advantage. During the refuelling procedure, a leak check of the closure plug is generally performed when the snout cavity is at park pressure. The lock of the present invention remains engaged during such a leak check. Alternatively, the closure plug check may be performed with the snout cavity at atmospheric pressure to allow for a combined closure plug/snout plug leak check. In this case, the lock retracts prior to the leak check but will re-engage if the pressure in the snout cavity increases above a pre-set level.
Although the lock has been described for use with a fuelling machine, it can also be used with a defuelling machine or an inspection machine, both of which are pressure vessels that connect to the fuel channel in a manner similar to that of the fuelling machine.
The lock has also been described for use in association with a clamping mechanism consisting of clamp jaws on clamp arms. It should be noted that other clamping or sealing mechanisms can be used and the lock provides a means of securing any such alternative mechanism.
The present invention has been shown and described with reference to preferred embodiments of the invention. It is to be understood that departures may be made therefrom within the spirit and scope of the invention.
The lock of the present invention acts to prevent inadvertent unclamping of the fuelling machine from the fuel channel in conditions in which the prior art locks do not. The action of the lock is based on the differential pressure between the snout cavity and the fuelling machine magazine. The lock is engaged when the snout cavity pressure and the fuelling machine pressure are substantially equalized. This occurs before the snout and fuel channel closures are removed. Thus, the lock remains engaged if there is a drop in reactor pressure during refuelling and the lock is also operational during reactor shutdown conditions when the reactor pressure is substantially reduced. Once refuelling is complete and the closures are replaced, the snout cavity pressure is vented and the fuelling machine magazine pressure acts to disengage the lock. Thus, the lock remains engaged if there is a drop in reactor pressure during refuelling. The lock is also operational during reactor shutdown conditions when the reactor pressure is substantially reduced.
Thus in accordance with the present invention, there is provided a means for locking a connecting mechanism, said connecting mechanism adapted to sealingly engage a first pressure vessel and a second pressure vessel at an interconnecting passageway, comprising: closure means in said passageway effective to maintain a pressure differential between said first and second pressure vessels; means for pressurizing said first pressure vessel to pressure of said second pressure vessel to eliminate said pressure differential and allow removal of said closure into the interior of said first pressure vessel permitting access to the interior of said second pressure vessel from said first pressure vessel; a rod and piston longitudinally movable within a hydraulic chamber between a first position effective to lock said connecting mechanism and a second position effective to unlock said connecting mechanism, the rod end of said chamber in fluid communication with the first pressure vessel side of said closure means and the piston end of said chamber in fluid communication with the second pressure vessel side of said closure means; wherein the elimination of said pressure differential is effective to move said rod and ;piston to said first position.
In accordance with another aspect of the present invention, there is provided a means for llocking a connecting mechanism, said connecting mechanism adapted to sealingly engage a first pressure vessel and a second pressure vessel at an interconnecting cavity in an interconnecting passageway, comprising: a first closure means in said passageway effective to maintain a first pressure differential between said first pressure vessel and said interconnecting cavity; a second closure means in said passageway effective to maintain a second pressure differential between said second pressure vessel and said interconnecting cavity; means for pressurizing said interconnecting cavity to pressure of said first pressure vessel to eliminate said first pressure differential and allow removal of said first closure means into interior of said first pressure vessel; means for depressurizing said interconnecting cavity to establish a pressure differential between said interconnecting cavity and said first pressure vessel; and a rod and piston longitudinally movable within a hydraulic chamber between a first position effective to lock said connecting mechanism and a second position effective to unlock said connecting mechanism, the rod end of said chamber in fluid communication with said first pressure vessel and the piston end of said chamber in fluid communication with said interconnecting cavity;
wherein the elimination of said pressure differential is effective to move said rod and piston to said first position and the establishment of said pressure differential is effective to move said rod and piston to said second position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The fuel channels of a CANDU~ reactor are refuelled by means of a remotely operated fuelling machine which removes spent fuel bundles from the fuel channel and replaces them with fresh fuel bundles. The spent fuel bundles and the fresh fuel bundles are stored in fuel ports in the fuelling machine. In order for the refuelling process to take place, the head of the fuelling machine is connected to the fuel channel in the manner illustrated in FIG. 1.
Fuel channel 10 is a longitudinal cylindrical assembly of approximately 4 inches in inside diameter and is adapted to contain a series of fuel bundles in end-to-end relation. High pressure heavy or light water coolant enters fuel channel 10 at one end, flows through the fuel bundles to cool the fuel rods .and remove heat produced by the fission process, and exits from fuel channel 10 at the opposite end. An end fitting, one of which is shown by reference numeral 12, is affixed to each end of fuel channel 10. Closure plugs, one of which is shown by reference numeral 14, are removable closures for fuel channel 10 which fit within the distal portion of each end fitting 12 and function to contain the contents of fuel channel 10. The pressure boundary for fuel channel 10 is at closure plug 14.
The fuelling machine head is a pressure vessel which contains a fuel loading mechanism.
Fuel loading magazine (a portion of which is shown at reference numeral 20) receives fuel into vacant positions for insertion into and removal from fuel channel 10. Snout 22 is a barrel-like extension of fuelling machine magazine 20 through which the fuel bundles pass to fuel channel 10. Fuelling machine snout plug 24 is a removable closure positioned within snout 22. The pressure boundary of fuelling machine is at snout plug 24.
A metallic seal between end fitting 12 and snout 22 is effected by clamp 26.
Clamp 26 consists of clamp jaws 28 on arm 30. Clamp jaws 28 are wedge elements which are pulled down into groove 32 on the outside of end fitting 12 to pull end fitting 12 and snout 22 tightly together.
A snout drive assembly drives clamp 26. In the embodiment illustrated in FIG.
l, the snout drive assembly is a screw-based linear actuator consisting of clamping barrel 34 on end fitting 12, ring gear 36 and gear rack 38. Gear rack 38 drives ring gear 36 which pulls barrel back towards fuelling machine and applies pressure to clamp 26 causing activation of jaws 28. Other types of snout drive assemblies may be used, for example, rack and pinion or sprag disc type assemblies.
When end fitting 12 and snout 22 are sealed, the volume surrounding the distal portion of snout plug 24 is contained and is referred to as snout cavity 16.
The lock of the present invention, illustrated by reference numeral 40 in FIG.
1 and shown in greater detail in FIGS. 2 and 3, acts on the snout drive assembly to prevent unclamping of end fitting 12 and snout 22. With reference to FIG. 2, lock has a rod and piston-type assembly housed by casing 42. Piston 44 and spring 46 occupy hydraulic piston chamber 48. Spring 46 is engaged to floor of piston chamber 48 and is biased to bottom of piston 44 such that when spring 46 is compressed, piston 44 is positioned in the lower part of piston chamber 48 and when spring 46 is extended, piston 44 is positioned in the upper part of piston chamber 48. Rod 52 extends from top of piston 44 through upper part of casing 42. Upper portion of rod 52 extends through ambushing 52 to potentially engage gear rack 38.
Rod seal 54 and piston seal 56 provide fluid seals for the rod 50 and piston 44, respectively. Seals 54, 56 may be O-rings, T-rings or any other suitable seal type. Rod 50 has lubricating means (not shown) and grease wiper seal 58. The piston and lock diameters can be -7_ any suitable dimension. In a lock used with a typical snout drive assembly, the piston diameter is about 2 inches, the rod diameter is about 1 inch and the load of the spring in its extended position is about 52 pounds.
Lock 40 is connected to fuelling machine magazine 20 and snout cavity 16 in the manner illustrated in FIG. 1. Snout connection tube 60 attaches to piston port 62 and connects snout cavity 16 to piston side of piston chamber 48 through piston channel 64.
Magazine connection tube 66 attaches to rod port 68 and connects fuelling machine magazine 20 to rod side of piston chamber 48 through rod channel 70. 'Tubes 60, 66 are connected to snout cavity 16 and fuelling machine magazine 20 in any suitable manner and preferably, for reasons of convenience, to pre existing pressure lines or ports.
A magnet rod 72 is mounted on a threaded rod screwed into piston 44 within tube 73.
Reed type magnetic switches 74 are mounted on the outside of tube 73 at fixed positions.
Switches 74 detect the location of the magnet allowing for remote sensing of the position of piston 44.
Drain port 76 has horizontal channel 78 to drain fluid if rod seal 54 fails and vertical channel 80 to drain any fluid that may have leaked into the snout drive mechanism.
To refuel a fuel channel, the fuelling machine head magazine 20 is moved to the reactor face and snout 22 is connected to end fitting 12 by clamp 26. Assuming that the reactor is in operating mode, the pressure in fuel channel 10 is at reactor operating pressure. The pressure in fuelling machine magazine 20 is at park pressure and the pressure in snout cavity 16 is at reactor lbuilding pressure. Park pressure is the pressure required to cool the spent fuel contained in the fuelling machine magazine 20. More specifically, it corresponds to the minimum pressure at the :fuelling machine head necessary to ensure coolant flows back through the cooling pipes which extend from the fuelling machine head. Once snout 22 and end fitting 12 have been clamped together, a leak check of snout cavity 16 is performed. Snout cavity 16 is pressurized to magazine park pressure through a line (not shown) which may be independent or may extend iErom a T-piece in line 60.
Once the pressures in snout cavity 16 and fuelling machine magazine 20 are equalized, a ram assembly withdraws the snout plug into the interior magazine of the fuelling machine. The _g_ pressure in the fuelling machine is then raised to reactor operating pressure.
A ram assembly withdraws closure plug 14 into the interior magazine of the fuelling machine once the pressures in fuel channel 10, snout cavity 16 and fuelling machine magazine 20 are equalized. Once refuelling of a fuel channel has been completed, the ram assembly replaces closure plug 14 and the pressure in the fuelling machine is reduced to fuelling machine park pressure. The ram assembly then replaces snout plug 24. Once snout cavity 16 has been vented to reactor building pressure, the snout drive assembly operates to disengage clamp 26 and the fuelling machine is then moved away from the reactor face.
When end fitting 12 is initially clamped to snout 22, the difference between the pressure in fuelling machine magazine 20 and the pressure in snout cavity 16 is sufficient to generate a large enough force in the rod side of piston chamber 48 to keep spring 48 compressed and rod 50 within bushing 54. In this state, lock 40 is in its disengaged position as illustrated in FIG. 2. As soon as the fuelling machine magazine and snout cavity pressures are equalized to allow removal of snout plug 24, as a result of the greater surface area of piston 44, the pressure in the piston side of piston chamber 48 together with spring 46 causes piston 44 to rise within piston chamber 48 and rod 50 to emerge from bushing 54 and overlap with a stop bracket affixed to the bottom of gear rack 38. Alternatively, the bottom of gear rack 38 may have a recess sized for a bolt-like insertion of rod 50. The engagement of rod 50 with gear rack 38 immobilizes the snout drive assembly such that clamp 26 cannot be released. In this state, lock 40 is in its engaged position.
Lock 40 remains engaged as the fuelling machine pressure is raised to reactor operating pressure and channel closure plug 14 is removed, and continues to remain engaged throughout the refuelling process. Once refuelling is complete and channel closure plug 14 and snout plug 24 have been replaced, snout cavity 16 is vented to reactor building pressure whereas fuelling machine magazine remains at park pressure. hock 40 disengages when a large enough positive fuelling machine magazine to snout cavity pressure differential exists. The fuelling machine magazine pressure connected to the rod side of piston chamber 48 drives piston 44 down and rod 50 to retract from the stops or recess in gear rack 38 in the snout mechanism drive.
Magazine connection tube 66 is preferably placed in front of snout connection tube 60 so that any mechanical damage to the tubes affects magazine connection tube 66 first. This ensures that lock 40 remains engaged in such circumstances.
There are numerous advantages to the present invention.
The lock engages at an earlier stage in the refuelling process and, more specifically, engages before the fuelling machine is online with the reactor.
In addition, if there is a reduction or loss of pressure in a fuel channel while it is open to the fuelling machine, the magazine to snout cavity pressure differential will not exist and the lock will remain engaged. Even if all pressure is lost in the magazine and snout cavity, the spring will act to keep the lock engaged. As a result, if a loss of coolant accident, a main steam line break or other such upset or accident conditions occur, the lock will remain engaged and ensure that the fuelling machine does not become disconnected from the fuel channel. Not only is there a greater risk of inadvertent unclamping during such conditions but it is also during such an event that it is of particular importance that the lock remain engaged because if the fuelling machine were to become disconnected from the fuel channel during upset or accident conditions, the severity of any leakage of reactor coolant or spillage of nuclear fuel would be greater.
Another advantage of the lock of the present invention over prior art locks is that it operates during reactor shutdown conditions. When a reactor is in shutdown mode, the reactor pressure is generally less than about 50 psi. Refuelling often continues when the reactor is in this mode. The procedure is the same as when the reactor is in operating mode and the relative pressure sequence is the same. Because the engagement and disengagement of the lock is dependent on the snout cavity to fuelling magazine differential, the lock engages once the magazine and snout cavity pressure have been equalized. The prior art locks were not operational during shutdown conditions.
A further advantage of the lock of the present invention is that it prevents the fuelling machine from being removed from a fuel port in the level lowered condition when the snout plug is removed. This condition arises when the fluid level in the fuelling magazine head is lowered to allow the fuel to be passed through air from the heavy water into light water. If the snout plug is not sealing adequately, the leak rate will be too high and the pressure in the snout cavity will increase causing the lock to engage. The fuelling machine can then stay in place and capture the leaks. The re-engagement of the lock also allows another attempt at inserting the plug with an improved seal. Removal of the fuelling machine from a fuel port without the snout plug in place creates the opportunity for tritium to be leaked from the snout and for air and gas to be entrained in the magazine coolant which will affect the pH and may cause oxidation and precipitation, as well as sloshing of D20.
The lock of the present invention provides a further operational safety advantage. During the refuelling procedure, a leak check of the closure plug is generally performed when the snout cavity is at park pressure. The lock of the present invention remains engaged during such a leak check. Alternatively, the closure plug check may be performed with the snout cavity at atmospheric pressure to allow for a combined closure plug/snout plug leak check. In this case, the lock retracts prior to the leak check but will re-engage if the pressure in the snout cavity increases above a pre-set level.
Although the lock has been described for use with a fuelling machine, it can also be used with a defuelling machine or an inspection machine, both of which are pressure vessels that connect to the fuel channel in a manner similar to that of the fuelling machine.
The lock has also been described for use in association with a clamping mechanism consisting of clamp jaws on clamp arms. It should be noted that other clamping or sealing mechanisms can be used and the lock provides a means of securing any such alternative mechanism.
The present invention has been shown and described with reference to preferred embodiments of the invention. It is to be understood that departures may be made therefrom within the spirit and scope of the invention.
Claims (8)
1. A means for locking a connecting mechanism, said connecting mechanism adapted to sealingly engage a first pressure vessel and a second pressure vessel at an interconnecting passageway, comprising:
(a) closure means in said passageway effective to maintain a pressure differential between said first and second pressure vessels;
(b) means for pressurizing said first pressure vessel to pressure of said second pressure vessel to eliminate said pressure differential and allow removal of said closure into the interior of said first pressure vessel permitting access to the interior of said second pressure vessel from said first pressure vessel;
(c) a rod and piston longitudinally movable within a hydraulic chamber between a first position effective to lock said connecting mechanism and a second position effective to unlock said connecting mechanism, the rod end of said chamber in fluid communication with the first pressure vessel side of said closure means and the piston end of said chamber in fluid communication with the second pressure vessel side of said closure means;
wherein the elimination of said pressure differential is effective to move said rod and piston to said first position.
(a) closure means in said passageway effective to maintain a pressure differential between said first and second pressure vessels;
(b) means for pressurizing said first pressure vessel to pressure of said second pressure vessel to eliminate said pressure differential and allow removal of said closure into the interior of said first pressure vessel permitting access to the interior of said second pressure vessel from said first pressure vessel;
(c) a rod and piston longitudinally movable within a hydraulic chamber between a first position effective to lock said connecting mechanism and a second position effective to unlock said connecting mechanism, the rod end of said chamber in fluid communication with the first pressure vessel side of said closure means and the piston end of said chamber in fluid communication with the second pressure vessel side of said closure means;
wherein the elimination of said pressure differential is effective to move said rod and piston to said first position.
2. The means for locking a connecting mechanism of claim 1 wherein said first pressure vessel is a fuelling machine magazine, said second pressure vessel is a fuel channel in a nuclear reactor and said passageway is a fuelling machine snout cavity.
3. The means for locking a connecting mechanism of claim 2 wherein said closure means comprises a snout plug at the second pressure vessel side of said snout cavity and a fuel channel closure plug at the first pressure vessel side of said snout cavity.
4. A means for locking a connecting mechanism, said connecting mechanism adapted to sealingly engage a first pressure vessel and a second pressure vessel at an interconnecting cavity in an interconnecting passageway, comprising:
(a) a first closure means in said passageway effective to maintain a first pressure differential between said first pressure vessel and said interconnecting cavity;
(b) a second closure means in said passageway effective to maintain a second pressure differential between said second pressure vessel and said interconnecting cavity;
(c) means for pressurizing said interconnecting cavity to pressure of said first pressure vessel to eliminate said first pressure differential and allow removal of said first closure means into interior of said first pressure vessel;
(d) means for depressurizing said interconnecting cavity to establish a pressure differential between said interconnecting cavity and said first pressure vessel; and (e) a rod and piston longitudinally movable within a hydraulic chamber between a first position effective to lock said connecting mechanism and a second position effective to unlock said connecting mechanism, the rod end of said chamber in fluid communication with said first pressure vessel and the piston end of said chamber in fluid communication with said interconnecting cavity;
wherein a pre-determined level of reduction of said pressure differential is effective to move said rod and piston to said first position and the establishment of a pre-determined value of said pressure differential is effective to move said rod and piston to said second position.
(a) a first closure means in said passageway effective to maintain a first pressure differential between said first pressure vessel and said interconnecting cavity;
(b) a second closure means in said passageway effective to maintain a second pressure differential between said second pressure vessel and said interconnecting cavity;
(c) means for pressurizing said interconnecting cavity to pressure of said first pressure vessel to eliminate said first pressure differential and allow removal of said first closure means into interior of said first pressure vessel;
(d) means for depressurizing said interconnecting cavity to establish a pressure differential between said interconnecting cavity and said first pressure vessel; and (e) a rod and piston longitudinally movable within a hydraulic chamber between a first position effective to lock said connecting mechanism and a second position effective to unlock said connecting mechanism, the rod end of said chamber in fluid communication with said first pressure vessel and the piston end of said chamber in fluid communication with said interconnecting cavity;
wherein a pre-determined level of reduction of said pressure differential is effective to move said rod and piston to said first position and the establishment of a pre-determined value of said pressure differential is effective to move said rod and piston to said second position.
5. The means for locking a connection mechanism of claim 4 wherein said first pressure vessel is a fuelling machine magazine, said second pressure vessel is a fuel channel, said first closure means is a snout plug and said second closure means is a fuel channel closure plug.
6. The means for locking a connecting mechanism of claim 1 or 5 additionally comprising a bias means effective to urge said rod and piston to said first position.
7. The means for locking a connecting mechanism of claim 6 wherein said bias means is a spring.
8. The means for locking a connecting mechanism of claim 5 wherein the connecting mechanism is a clamp actuated by a gear rack and rack gear assembly and when said rod and piston are in said first position, said rod engages said gear rack.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2380909A CA2380909C (en) | 2002-04-08 | 2002-04-08 | Differential pressure based lock |
| CN2008100887607A CN101271739B (en) | 2002-04-08 | 2003-03-26 | Differential pressure based lock |
| CNB038117630A CN100431058C (en) | 2002-04-08 | 2003-03-26 | Differential pressure based lock |
| KR1020047016033A KR100978447B1 (en) | 2002-04-08 | 2003-03-26 | Differential pressure based lock |
| ROA200400876A RO122066B1 (en) | 2002-04-08 | 2003-03-26 | Coupling mechanism blocked by lock based on pressure difference |
| PCT/CA2003/000431 WO2003088263A2 (en) | 2002-04-08 | 2003-03-26 | Differential pressure based lock |
| HK05111497A HK1079613A1 (en) | 2002-04-08 | 2005-12-14 | Differential pressure based lock |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2380909A CA2380909C (en) | 2002-04-08 | 2002-04-08 | Differential pressure based lock |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2380909A1 true CA2380909A1 (en) | 2003-10-08 |
| CA2380909C CA2380909C (en) | 2013-04-30 |
Family
ID=29220474
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2380909A Expired - Fee Related CA2380909C (en) | 2002-04-08 | 2002-04-08 | Differential pressure based lock |
Country Status (6)
| Country | Link |
|---|---|
| KR (1) | KR100978447B1 (en) |
| CN (2) | CN100431058C (en) |
| CA (1) | CA2380909C (en) |
| HK (1) | HK1079613A1 (en) |
| RO (1) | RO122066B1 (en) |
| WO (1) | WO2003088263A2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9418765B2 (en) | 2013-03-14 | 2016-08-16 | Roger Ian LOUNSBURY | Nuclear reactor cores comprising a plurality of fuel elements, and fuel elements for use therein |
| CN112834111A (en) * | 2021-01-03 | 2021-05-25 | 浙江万纳核电检修有限公司 | Measuring tool and measuring method for nuclear power plant transfer equipment |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100954213B1 (en) * | 2008-10-07 | 2010-04-21 | 한전케이피에스 주식회사 | Emergency canceling machine of snout clamp in the nuclear fuel changer |
| CN101725590B (en) * | 2009-11-30 | 2011-11-16 | 南京康尼机电股份有限公司 | Air driving device with locking unit |
| CN109027286B (en) * | 2018-09-14 | 2024-07-09 | 湖州道和汽车零部件有限公司 | Novel hydraulic glasses valve |
| CN109812616A (en) * | 2019-02-27 | 2019-05-28 | 江苏雄越石油机械设备制造有限公司 | A kind of safe antitheft gate valve |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB854763A (en) * | 1956-12-10 | 1960-11-23 | Thompson Nuclear Energy Co Ltd | Improvements relating to gas tight couplings |
| GB886630A (en) * | 1960-02-17 | 1962-01-10 | Flight Refueling Ltd | Improvements in or relating to plugs or closures |
| DE1209672B (en) * | 1961-08-16 | 1966-01-27 | Commissariat Energie Atomique | Stopper for reactor ducts |
| US3157579A (en) * | 1962-03-05 | 1964-11-17 | Ca Atomic Energy Ltd | Nuclear reactor fueling machine |
| US3597317A (en) * | 1968-04-15 | 1971-08-03 | Ca Atomic Energy Ltd | Nuclear reactor fuelling machine |
| CA891193A (en) * | 1970-10-26 | 1972-01-18 | Her Majesty In Right Of Canada As Represented By Atomic Energy Of Canada Limited | Method and apparatus for fuelling a pressurised nuclear reactor |
| CA1015470A (en) * | 1974-03-13 | 1977-08-09 | William S. Cashen | Nuclear reactor machine refuelling system |
| US4392556A (en) * | 1978-08-25 | 1983-07-12 | Arkwin Industries, Inc. | Actuator locking device |
| CA1192679A (en) * | 1982-12-10 | 1985-08-27 | William S. Cashen | Fuel channel closure and adapter |
| DK150026C (en) * | 1983-08-11 | 1987-06-22 | Kosan Teknova As | REGULATOR FOR GAS BOTTLE EXPLOSION STUDS |
| FR2636768B1 (en) * | 1988-09-19 | 1990-12-14 | Framatome Sa | REMOVABLE FUEL ASSEMBLY FOR A NUCLEAR REACTOR COOLED BY LIGHT WATER |
| CN2177840Y (en) * | 1993-07-27 | 1994-09-21 | 郑州工学院 | Locking device capable of quickly opening door or cover of pressure vessel |
| FR2724710B1 (en) * | 1994-09-16 | 1996-12-20 | Staubli Sa Ets | QUICK CONNECTION WITH CONTROLLED COUPLING |
| FR2724709B1 (en) * | 1994-09-16 | 1996-12-20 | Raymond Sperlich | CONNECTION DEVICE FOR PRESSURE FLUID CONTAINER TAP |
-
2002
- 2002-04-08 CA CA2380909A patent/CA2380909C/en not_active Expired - Fee Related
-
2003
- 2003-03-26 RO ROA200400876A patent/RO122066B1/en unknown
- 2003-03-26 CN CNB038117630A patent/CN100431058C/en not_active Expired - Fee Related
- 2003-03-26 WO PCT/CA2003/000431 patent/WO2003088263A2/en active Application Filing
- 2003-03-26 CN CN2008100887607A patent/CN101271739B/en not_active Expired - Fee Related
- 2003-03-26 KR KR1020047016033A patent/KR100978447B1/en not_active IP Right Cessation
-
2005
- 2005-12-14 HK HK05111497A patent/HK1079613A1/en not_active IP Right Cessation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9418765B2 (en) | 2013-03-14 | 2016-08-16 | Roger Ian LOUNSBURY | Nuclear reactor cores comprising a plurality of fuel elements, and fuel elements for use therein |
| CN112834111A (en) * | 2021-01-03 | 2021-05-25 | 浙江万纳核电检修有限公司 | Measuring tool and measuring method for nuclear power plant transfer equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20040105858A (en) | 2004-12-16 |
| KR100978447B1 (en) | 2010-08-26 |
| RO122066B1 (en) | 2008-11-28 |
| WO2003088263A3 (en) | 2004-03-04 |
| CN101271739B (en) | 2012-04-04 |
| WO2003088263A2 (en) | 2003-10-23 |
| CN101271739A (en) | 2008-09-24 |
| CA2380909C (en) | 2013-04-30 |
| CN1656569A (en) | 2005-08-17 |
| CN100431058C (en) | 2008-11-05 |
| HK1079613A1 (en) | 2006-04-07 |
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| EEER | Examination request | ||
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