CA2041852C - Garter spring magazine - Google Patents
Garter spring magazineInfo
- Publication number
- CA2041852C CA2041852C CA002041852A CA2041852A CA2041852C CA 2041852 C CA2041852 C CA 2041852C CA 002041852 A CA002041852 A CA 002041852A CA 2041852 A CA2041852 A CA 2041852A CA 2041852 C CA2041852 C CA 2041852C
- Authority
- CA
- Canada
- Prior art keywords
- tube
- carriage
- calandria
- protective sleeve
- magazine
- 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.)
- Expired - Lifetime
Links
Classifications
-
- 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
- G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
- G21C3/32—Bundles of parallel pin-, rod-, or tube-shaped fuel elements
- G21C3/335—Exchanging elements in irradiated bundles
-
- 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
- G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
- G21C3/32—Bundles of parallel pin-, rod-, or tube-shaped fuel elements
- G21C3/33—Supporting or hanging of elements in the bundle; Means forming part of the bundle for inserting it into, or removing it from, the core; Means for coupling adjacent bundles
-
- 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
- G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
- G21C3/32—Bundles of parallel pin-, rod-, or tube-shaped fuel elements
- G21C3/336—Spacer elements for fuel rods in the bundle
-
- 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
Landscapes
- 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
There is described a system for use in a nuclear reactor pressure tube replacement program. The system employs a carriage and stop mechanism and a magazine. The system is used to deposit fuel channel annular spacers around the circumference of the reactor pressure tubes to maintain a space between the pressure tubes and the calandria tubes. A protective sleeve assembly and nose cone house a pressure tube. A fuel channel annular spacer magazine is attached to the end of the protective sleeve assembly and the whole is loaded through a lattice tube opening in the reactor end shield wall into a calandria tube. A travel tube housing a chain-driven carriage is placed in position on the other side of the calandria tube through the lattice tube opening in the opposite wall of the reactor. It is used to remove the nose cone and protective sleeve from the pressure tube while depositing fuel channel annular spacers at predetermined intervals.
Description
2~418~~
DISCLOSURE
This invention relates to nuclear reactors and in particular, the replacement of pressure tubes or fuel channels in a nuclear reactor.
BACKGROUND OF THE INVENTION
This invention particularly relates to nuclear reactors which use a heavy water moderator in the calandria. A reactor of this type is the Candu* reactor. The Candu* reactor houses hundreds of horizontally placed tubes within the calandria. These are known as calandria tubes. Surrounding the calandria tubes is a heavy water moderator D20.
Within each calandria tube is a pressure tube or fuel channel. The fuel channel houses bundles of uranium which are used as the reactor fuel. Travelling through the pressure tubes is a heavy water coolant. The heavy water coolant absorbs heat as fission takes place within the reactor chamber. The coolant carries this heat to boilers which heat light water (H20) to produce steam to drive steam turbines. These turbines drive generators in conventional fashion to produce electrical energy.
The temperature of the heavy water moderator surrounding the calandria tubes is typically about 140°F. while the temperature of the heavy water coolant running through the pressure tubes is considerably higher, around 270°F. Because of the difference in temperatures between the two fluids it is necessary to separate one tube from the other in the annular space, with fuel channel annular spacers. Such spacers are typically known in the art as garter springs and are produced from *Trade-mark 204~8~2 a coiled spring-like material of a thickness substantially equal to the difference in diameter between the inside of the calandria tube and the outside of the pressure tube. Thus the garter spring substantially fills the annular space between the pressure tube and the calandria tube.
Pressure tubes are typically constructed of zirconium and are made to withstand extreme pressures & heat. However, metal fatigue causes the pressure tubes to creep and sag within the calandria tubes and thus they must be replaced after their useful life.
The process of replacing pressure tubes within a nuclear reactor is both dangerous, because of radioactive contamination, and time consuming. In the present art, the pressure tubes are carefully placed within the calandria tube by means of a carriage apparatus. The pressure tube has an end fitting which rests in a lattice tube opening in one wall of the reactor. From the lattice tube opening of the opposite wall of the nuclear reactor, men manually use a long reaching tool to push the fuel channel annular spacers along the pressure tube to predetermined positions thereby separating the exterior wall of the pressure tube from the interior wall of the calandria tube.
Problems are encountered during this process. It is difficult to place the garter springs or fuel channel annular spacers in a particular position. Furthermore, each time the tool is withdrawn from the calandria tube a measure of radioactive contamination may be encountered. It is therefore necessary to clean the tool each time a spacer is inserted to prevent contamination. In addition, some scoring damage may be done to 204~~~~
DISCLOSURE
This invention relates to nuclear reactors and in particular, the replacement of pressure tubes or fuel channels in a nuclear reactor.
BACKGROUND OF THE INVENTION
This invention particularly relates to nuclear reactors which use a heavy water moderator in the calandria. A reactor of this type is the Candu* reactor. The Candu* reactor houses hundreds of horizontally placed tubes within the calandria. These are known as calandria tubes. Surrounding the calandria tubes is a heavy water moderator D20.
Within each calandria tube is a pressure tube or fuel channel. The fuel channel houses bundles of uranium which are used as the reactor fuel. Travelling through the pressure tubes is a heavy water coolant. The heavy water coolant absorbs heat as fission takes place within the reactor chamber. The coolant carries this heat to boilers which heat light water (H20) to produce steam to drive steam turbines. These turbines drive generators in conventional fashion to produce electrical energy.
The temperature of the heavy water moderator surrounding the calandria tubes is typically about 140°F. while the temperature of the heavy water coolant running through the pressure tubes is considerably higher, around 270°F. Because of the difference in temperatures between the two fluids it is necessary to separate one tube from the other in the annular space, with fuel channel annular spacers. Such spacers are typically known in the art as garter springs and are produced from *Trade-mark 204~8~2 a coiled spring-like material of a thickness substantially equal to the difference in diameter between the inside of the calandria tube and the outside of the pressure tube. Thus the garter spring substantially fills the annular space between the pressure tube and the calandria tube.
Pressure tubes are typically constructed of zirconium and are made to withstand extreme pressures & heat. However, metal fatigue causes the pressure tubes to creep and sag within the calandria tubes and thus they must be replaced after their useful life.
The process of replacing pressure tubes within a nuclear reactor is both dangerous, because of radioactive contamination, and time consuming. In the present art, the pressure tubes are carefully placed within the calandria tube by means of a carriage apparatus. The pressure tube has an end fitting which rests in a lattice tube opening in one wall of the reactor. From the lattice tube opening of the opposite wall of the nuclear reactor, men manually use a long reaching tool to push the fuel channel annular spacers along the pressure tube to predetermined positions thereby separating the exterior wall of the pressure tube from the interior wall of the calandria tube.
Problems are encountered during this process. It is difficult to place the garter springs or fuel channel annular spacers in a particular position. Furthermore, each time the tool is withdrawn from the calandria tube a measure of radioactive contamination may be encountered. It is therefore necessary to clean the tool each time a spacer is inserted to prevent contamination. In addition, some scoring damage may be done to 204~~~~
both the calandria tube and the pressure tube during -the installation process. Damage to the pressure tubes and calandria tubes lowers the life expectancy of these components.
It is an object of the present invention to provide a system for installing replacement pressure tubes with fuel channel annular spacers efficiently with a minimal amount of radio active contamination and a minimal amount of damage to the calandria tubes and replacement pressure tubes.
It is a further object of the present invention to provide a system wherein the fuel channel annular spacers are placed at precise predetermined positions.
Therefore this invention seeks to provide a system for depositing fuel channel annular spacers between pressure tubes and calandria tubes in a nuclear reactor comprising in combination: a protective sleeve assembly adapted to surround a replacement pressure tube and adapted to pass through a calandria tube; said protective sleeve assembly including a magazine operable to deposit fuel channel annular spacers along a pressure tube to separate said pressure tube from said calandria tube; means for inserting said protective sleeve assembly and said replacement pressure tube into said calandria tube from one side of said reactor; a protective sleeve removal tool adapted to remove said protective sleeve assembly from said pressure tube and sand calandria tube from the opposite side of said reactor from which said protective sleeve assembly is inserted; said protective sleeve removal tool including a magazine actuating means operable to actuate said magazine to serially deposit fuel channel annular spacers in spaced relation along said pressure tube while said 2~4~8~~
It is an object of the present invention to provide a system for installing replacement pressure tubes with fuel channel annular spacers efficiently with a minimal amount of radio active contamination and a minimal amount of damage to the calandria tubes and replacement pressure tubes.
It is a further object of the present invention to provide a system wherein the fuel channel annular spacers are placed at precise predetermined positions.
Therefore this invention seeks to provide a system for depositing fuel channel annular spacers between pressure tubes and calandria tubes in a nuclear reactor comprising in combination: a protective sleeve assembly adapted to surround a replacement pressure tube and adapted to pass through a calandria tube; said protective sleeve assembly including a magazine operable to deposit fuel channel annular spacers along a pressure tube to separate said pressure tube from said calandria tube; means for inserting said protective sleeve assembly and said replacement pressure tube into said calandria tube from one side of said reactor; a protective sleeve removal tool adapted to remove said protective sleeve assembly from said pressure tube and sand calandria tube from the opposite side of said reactor from which said protective sleeve assembly is inserted; said protective sleeve removal tool including a magazine actuating means operable to actuate said magazine to serially deposit fuel channel annular spacers in spaced relation along said pressure tube while said 2~4~8~~
protective sleeve assembly is being removed therefrom.
This invention further seeks to provide a system for depositing .fuel channel annular spacers between pressure tubes and calandria tubes in a nuclear reactor comprising: a carriage adapted for two-directional movement within an elongate travel tube; said elongate travel tube being adapted to be aligned with the calandria tube in one sidewall of said reactor; means for controlling movement of said carriage predetermined distances in the forward and rearward directions; said carriage including a grasping mechanism adapted to move a protective sleeve assembly within a calandria tube; said protective sleeve assembly comprising a graspable nose cone, a protective sleeve, and an annular spacer magazine; said protective sleeve and said magazine being of annular configuration and adapted to fit between said pressure tubes and said calandria tubes; said annular spacer magazine adapted to hold a plurality of annular spacers of resilient material; whereby when in operation said carriage is activated in the forward direction said protective sleeve assembly is withdrawn a predetermined distance from said pressure tube; and when said carriage is reversed in direction, said magazine is activated and an annular spacer is deposited between said pressure tube and said calandria tube.
Rather than installing the fuel channel annular spacers or garter springs once the new pressure tubes have been replaced in the calandria tubes, the present invention loads the annular spacers onto the new replacement pressure tubes outside of the reactor prior to replacement. These are placed in a unique magazine which is adapted to fit over the pressure tube and be ~~4~~~~
coupled by means of a threaded end to a protective plastic sleeve.
The other end of the plastic sleeve is coupled to a cone shaped nose portion. To balance the weight of the nose portion a counterweight, which is directed into the pressure tube by rollers, is used. The counterweight lies within one end of the replacement pressure tube. On the other end of the pressure tube is an end fitting which remains on the pressure tube once it is placed in the calandria tube.
A lifting device is used to move (one at a time), each of the entire protective sleeve pressure tube assemblies through the respective lattice tube openings in the reactor wall into each of the respective calandria tubes.
Once the protective sleeve assembly along with pressure tube end fitting is in place within the calandria tube, the travel tube which houses a carriage, is moved into a lattice tube extension sleeve which fits within a lattice tube in the calandria tube opening on the opposite side of the reactor. The carriage is then activated by an air motor coupled to a chain drive. The carriage then grasps the nose cone which is coupled to the protective sleeve assembly. The carriage moves away from the reactor wall and removes the protective sleeve from the newly replaced pressure tube. By this procedure, scoring is substantially reduced.
As the protective plastic sleeve is removed, fuel channel annular spacers are deposited at predetermined intervals along the pressure tube in a manner hereinafter described.
The predetermined positioning of the fuel channel annular spacers on the pressure tubes is determined by a series of 204~~j~
stop blocks which can rotatably be moved in and out of the travel tube which houses the carriage. The carriage is equipped with a retractable stop and a fixed stop.
As the carriage moves outwardly from the reactor wall by means of a chain drive and air motor, it abuts the first stop block with the retractable stop and then travels along until the fixed stop comes to rest against the stop block. The carriage is then reversed in direction, and presses the plastic protective sleeve coupled to the magazine and nose cone, back into the calandria tube, The distance travelled in reverse is predetermined by the length of the stop block and the gap between the fixed stop and the retractable stop.
The magazine which holds the four fuel channel annular spacers is comprised of an inner sleeve and an outer sleeve. The inner sleeve has friction bands on its inner cylindrical surface which cause the inner sleeve to remain in place on the pressure tube while the outer sleeve moves rearwardly when the carriage is in reverse. As the outer sleeve moves rearwardly, a fuel channel annular spacer is rolled between the inner sleeve and the outer sleeve and finally deposited on the pressure tube.
Thereafter, an operator removes the stop block from the travel tube of the carriage and the carriage moves in the forward direction until the next stop block is encountered. Each successive stop block in the path of the carriage is of successively shorter length. This determines the distance of rearward travel of the carriage.
The reason for increased reverse travel at each successive stop block is as follows. Within the magazine in the 2~~18~~
outer sleeve are a series of internal circumfe.rential grooves.
Typically there are four, but any number can be constructed depending upon the number of spacers required to be placed on the pressure tube. These grooves are placed approximately an inch apart. For that reason, it is necessary for the outer sleeve to travel rearwardly approximately an inch further each successive time that a fuel channel annular spacer is to be deposited.
Once the final .fuel channel annular spacer is deposited the carriage moves the protective sleeve assembly along with the nose cone and the magazine out of the calandria tube and off of the pressure tube and the operation is complete. The protective sleeve and nose cone and reloaded magazine are then placed on another replacement pressure tube which is destined to fit through a second calandria tube opening in the right hand reactor wall and the process is again repeated.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the invention will be further described in conjunction with the following drawings wherein:
Figure 1 is a schematic diagram of a nuclear reactor portion of a nuclear power plant;
Figure 2 is a detail (partially in section) of a conventional apparatus used to insert a protective tube assembly and replacement pressure tube into a calandria tube;
Figure 3 is a detail in sectional elevation of the carriage retracting tool and stop block mechanism for withdrawing the protective tube assembly from the calandria tube;
figure 4 is a view similar to Figure 3 but to a larger 204~8~2 scale;
Figure 5 is a perspective view of the magazine;
Figure 6 is a longitudinal section of the magazine and protective tube assembly in the stationary position on the pressure tube;
Figure 7 is a view similar to Figure 6 wherein the carriage has moved in reverse; and Figure 8 is a perspective view of a magazine loading tool.
Figure 1 shows a schematic view of the internal vault of a nuclear reactor; the reactor vault 1 is surrounded by left and right thick walls 2 and 2A, often referred to as end shields. A
series of horizontally disposed calandria tubes 3 run from sidewall to sidewall. The reactor vault is filled with a heavy water moderator 4 which surrounds the calandria tubes 3. The heavy water moderator 4 is circulated by a pump (not shown) through a heat exchanger (not shown) and then returned to the reactor vault, in a conventional fashion.
Horizontally disposed within each of the calandria tubes 3 are pressure tubes 5 in which fuel bundles 6 are placed. The fuel bundles are comprised of pencil like pelleted natural uranium. Heavy water coolant 7 is pumped through the inside of the pressure tubes, also known as fuel channels, in a usual manner.
Typically, in a Candu* reactor, fresh fuel is remotely placed in one end of a fuel channel while a simultaneous operation at the other end removes spent fuel. Since the flow path of the *Trade-mark 24~185~
heavy water coolant 7 occurs in alternating directions from channel to channel, fuel loading and removal occurs at alternating ends of the reactor. The fuel loading and removal operations are (unlike most other reactors) performed while the reactor is on power. These operations are carried out by remote operated machines because the radiation fields, during reactor operation, are too high for personnel to access the ends of the fuel channels.
During pressure tube replacement the worn pressure tubes 5 are removed from the calandria tubes 3.
Figure 2 shows a loading/insertion tool 40 at the right hand side of the reactor. Within the reactor, is shown the calandria tube 3 and the calandria tube opening 3a in the end wall 2A which is surrounded by a permanently embedded lattice tube 44, having an enlarged diameter at the outer side. A loading/
insertion tool 40 of a known type is used to insert a pressure tube 5 and a protective plastic outer sleeve 13 assembly through opening 3a into the calandria tube 3.
Turning briefly to Figure 3, one notes that in both the right hand side of the reactor end wall 2A and the left hand side of the reactor bounded by wall 2, the calandria tube openings 3A
are surrounded by a permanently embedded circular lattice tube 44 to provide ready access to the calandria tube 3 during pressure tube 5 replacement. Lattice tube extension sleeve 45 is fixedly connected to the lattice tube 44, in a conventional manner, as shown in Figures 3 and 4. Prior to insertion of the pressure tube into the calandria tube a protective sleeve assembly is assembled together. A nose cone 14 is attached to one end of the protective 2~~~~~~
plastic outer sleeve 13. threadedly mounted to the rear of the plastic sleeve 13 is a magazine 10. To the right of the magazine 10 and at the end of the pressure tube 5, an end fitting 43 is permarnently attached to pressure tube 5.
The loading insertion tool 40 has a suspended carriage 38 which supports the end fitting 43 by an end fitting carriage portion 42. A pressure tube support roller 39 supports pressure tube 5 and its protective plastic sleeve 13. Once the pressure tube 5, protective plastic sleeve 13, magazine 10, end fitting 43 10 and nose cone 14 are assembled into a protective sleeve assembly, the assembly is moved by the loading insertion tool to the left through the calandria tube opening 3A into the calandria tube 3.
After the pressure tube is inserted in the calandria tube, end fitting 43 is adapted to sit within opening 3a within lattice tube 44 and is fixedly secured therein in a known manner.
In Figure 3 the protective sleeve assembly is shown in place in the calandria tube 3a. The protective sleeve 13, pressure tube 5, magazine 10 and nose cone 14 have been inserted as shown in Figure 2 from the left side of the vault through the calandria tube opening 3A.
As seen in Figure 3 the nose cone 14 is attached to a nose cone counterweight 15 having rollers 37. The counterweight 15 extends rearwardly from the nose cone 14 into the pressure tube 5, The counterweight 15 is necessary to counter the weight of the nose cone 14 when the total assembly is being placed into the calandria tube.
Shown on the left hand side of the reactor wall 2 in Figure 3 is a protective sleeve assembly removal tool. Once the 20~185~
protective sleeve assembly is in place within the calandria tube 3, this protective sleeve assembly removal tool is moved into position. The removal tool consists essentially of a carriage 47 within a travel tube 16 (see particularly Figure 4). Travel tube 16 is inserted within lattice tube extension sleeve 45, and the latter is locked in place within lattice tube 44 in a conventional manner. The opening 3A in wall 2 is similar to that in wall 2A in that it is smaller at the reactor side than the outer side of wall 2. Travel tube 16, after being inserted in lattice tube extension sleeve 45, is locked in place therein by means of a locking ring 45A. Carriage 47 is supported within travel tube 16 by means of a plurality of rollers 37. Rollers 37 are adapted to position the carriage 47 within the center of travel tube 16.
Carriage 47 is arranged for reciprocal motion within travel tube 16. A pair of endless chains 46 are arranged longitudinally on either side of the inside of the travel tube 16 such that they are diametrically apart, permitting carriage 47 to move between them. Carriage 47 is drivingly connected to the chains 46 by means of a cross-bar (not shown). The chains are moved by means of an air motor (not shown), which is located at the outboard end of travel tube 16. The air motor, through a known gear arrangement drives the endless chains 46 by an outer sprocket 48A. The endless chains 46 turn around independent sprockets 48, one of which is mounted for each chain to each side of the travel tube 16, close to the reactor wall 2. By activating the air motor (not shown) in either direction, the carriage can be moved to the left and to the right, hereinafter kndwn as forward and rearward, within travel tube 16.
Carriage 47 has a carriage grasp 27 which automatically secures the nose cone 14 of the protective sleeve assembly when the carriage is activated into position.
In Figure 3 on the right hand side of the protective sleeve 13 and adjacent end fitting 43, (which is located at the right side of pressure tube 5), is a series of four fuel channel annular spacers 9 located within magazine 10.
Magazine 10 will be more clearly shown in drawings 5, 6 and 7, later to be described. Carriage 47 has a retractable front carriage stop 28 and a fixed carriage stop 29. A series of stop blocks 30, 31, 32 and 33, of successively shorter lengths, are located along a common shaft schematically shown at 34, adjacent travel tube 16. Openings 16B are located along the travel tube and allow an operator, by rotation of the control handle 35, to rotate stop blocks 30 through 33 into and out of travel tube 16.
Turning to Figure 5, a perspective view of the fuel channel annular spacer magazine 10 is shown looking at the trailing end. The magazine has an outer sleeve 17 and an inner sliding sleeve 18. Figure 5, for the sake of illustration, shows the inner sleeve 18 moved forwardly somewhat of the outer sleeve 17. In a preferred embodiment, the magazine has four internal grooves 20. Only three of these grooves are illustrated in Figure 5 and one of the grooves has already been fitted with a fuel channel annular spacer 9. Normally, once all of the grooves 20 of the magazine 10 have been loaded with fuel channel annular spacers 12a 9 in preparation for deposit along replacement pressure tube 5, the inner sleeve 18 and the outer sleeve 17 trailing ends (18A, 17A, respectively as shown in Figures 6 and 7) are adjacent one another, thereby retaining 2~4~~~2 the :Fuel channel annular spacers 9 prior to deposit.
In a preferred embodiment the outer sleeve is 12.72'°
long and the inner sleeve is 6.44" long. There is an annular gap between the two sleeves of .15". The outer sleeve is equipped with a circumferential outer guide ring 19 vahich is adapted to fit closely to the inner walls of calandria tube 3. The outer sleeve 17, adjacent one end, includes four internal circumferential grooves 20, which are adapted to hold the fuel channel annular spacers 9, three of which only are shown in Figure 5 for the sake of clarity.
~s can be seen in Figure 5, the fuel channel annular spacer 9 is comprised of a coiled spring. The magazine outer sleeve 17 is equipped with viewing holes 21 which register with each of the grooves 20. This allows the operator to see if the coiled springs are in place before threadedly attaching the magazine 10 on the protective sleeve 13. On the forward end of the outer sleeve 17 are three equally circumferentially spaced open-ended slots, the top one of which is shown at 23, which measure 8.56" long and 2.03" wide, in a preferred embodiment.
The inner sleeve 18 is equipped with three corresponding segmented equally circumferentially spaced protruding nylon motion limiting stop lugs, the top one of which is shown at 24, protruding through slot 23. Lugs 24 cooperate with slots 23 and prohibit the inner sleeve 18 from sliding rearwardly out of the outer sleeve 17 during the process of depositing the fuel channel annular spacers 9 on the pressure tubes 5. The slotted forward end of the outer sleeve 17 is equipped with a female internal thread which is adapted to threadedly engage the threaded end of the protective sleeve 13.
Figures 6 and 7 are sectional views of the magazine connected to the protective sleeve 13 surrounding a pressure tube 5. Figure 6 is shown in the condition of Figure 3 but with the calandria tube 3 removed for clarity. In Figure 6 the right hand end of the inner sleeve 18 (the trailing end), shown as 18A and the right hand end of the outer sleeve 17 shown as 17A (the trailing end), terminate at approximately the same point.
10 In Figure 7, however, the trailing end 17A of outer sleeve 17 has been pushed rearwardly beyond the trailing end 18A of the inner sleeve 18, thus being in a condition to allow the deposit of a fuel channel annular spacer 9 onto pressure tube 5, as will be explained more fully hereinafter.
In Figures 6 and 7 the pressure tube protective sleeve 13 is bonded to a plastic connector 12 which has a male thread 26 adapted to engage the female thread 26A of outer sleeve 17 of magazine 10. The inner sleeve 18 shown as 18A
in Figures 6 and 7 is equipped with two nylon friction rings 25 which are resiliently forced inwardly by leaf-springs 25A.
These rings 25 sit firmly in contact with pressure tube 5. In Figures 6 and 7 two friction rings 25 are shown, however, in a preferred embodiment three friction rings 25 can be used.
Figure 8 shows a tool for serially loading fuel channel annular spacers 9 into the magazine 10. The tool has a spacer receiving nose 22B and a shoulder stop 22A. The nose 14a 22B is inserted into the magazine until a spacer 9 is received in a groove 20, whereupon the tool 22 is withdrawn, the spacer being drawn over the nose 22B.
204~8~2 OPERATION OF THE INVENTION
The operation o.f the invention will be described hereinafter.
A worn pressure tube 5 has been removed from a calandria tube 3, leaving openings 3A in the right and left walls (end shields) of the reactor open. A protective tube assembly holding the pressure tube 5 is first assembled at the right hand side of the reactor. Firstly the magazine 10 is loaded with four fuel channel annular spacers 9 with the help of the loading tool 22.
Once loaded, the trailing ends (17A and 18A, respectively), of outer sleeve 17 and inner sleeve 18 of the magazine 10 are adjacent one another. Magazine IO is then threadedly attached to connector 12 which is fixedly bonded to protective plastic sleeve 13. The protective plastic sleeve 13 is already fixedly attached to its nose cone 14 and the counterweight 15.
Protective plastic sleeve 13 coupled with magazine 10 is then pushed commencing at the magazine end onto a new replacement pressure tube 5. Near the end of pressure tube 5, adjacent the magazine Z0, an end fitting 43 is connected to the pressure tube 5.
The loading insertion tool 40 (Fig 2) lifts the complete protective tube assembly, housing the pressure tube 5 with its end fitting 43 into position near opening 3A of calandria tube 3 at the right hand side of the reactor. Thereafter, the complete assembly is moved through the calandria tube opening 3A, being guided by the nose cone 14 until the nose cone 14 .Lies within the left hand reactor wall 2 (see Fig. 3). At this point in the 2~4~~~~
operation, the assembly can move no further to the left as the end fitting 43 is in position within wall 2A within lattice tube 44 and then is secured in a conventional manner into the wall 2A of the reactor.
As shown in Figures 3 and 4, after the end fitting 43 is connected to the right hand wall 2A of the reactor, a lattice tube extension sleeve 45 is fitted into the lattice tube 44 in calandria tube inlet 3A in the left hand wall 2 of the reactor.
Travel tube 16, with carriage 47 therein, is then moved into position and inserted into lattice tube extension sleeve 45 and locked therein by means of locking ring 45A. The air motor mentioned above is then activated such that the chains 46 move the carriage 47 rearwardly within travel tube 16 into a position such that the carriage grasp 27 latches onto nose cone 14 of the protective tube assembly. The protective tube assembly removal tool is then in a position to withdraw the protective sleeve 13 off of replacement pressure tube 5 and out of calandria tube 3, while depositing fuel channel annular spacers 9 in predetermined positions on pressure tube 5 as hereinafter described.
The air motor by a known gear arrangement, reverses the direction of the carriage 47 such that the carriage 47 moves forwardly away from the wall 2 of the reactor within travel tube 16.
When retractable carriage stop 28 of carriage 47 strikes the first stop block 30 it retracts downwardly permitting the carriage to continue its forward motion until fixed stop 29 abuts stop 30. Thereafter the air motor is activated to move the carriage in the rearward direction a distance °'X" which in this 2418 ~~
instance is 1.38" as shown in Figure 4. The distance "X" is the dirt<~nce between the right hand side of stop 28 and the left hand side of stop block 30. The rearward movement of the carriage 47 cause s nose cone 14, counterweight 15, protective sleeve 13, and outer sleeve 17 of the magazine 10 to move in the reverse direction towards the right wall 2A of the reactor (see now Figs.
This invention further seeks to provide a system for depositing .fuel channel annular spacers between pressure tubes and calandria tubes in a nuclear reactor comprising: a carriage adapted for two-directional movement within an elongate travel tube; said elongate travel tube being adapted to be aligned with the calandria tube in one sidewall of said reactor; means for controlling movement of said carriage predetermined distances in the forward and rearward directions; said carriage including a grasping mechanism adapted to move a protective sleeve assembly within a calandria tube; said protective sleeve assembly comprising a graspable nose cone, a protective sleeve, and an annular spacer magazine; said protective sleeve and said magazine being of annular configuration and adapted to fit between said pressure tubes and said calandria tubes; said annular spacer magazine adapted to hold a plurality of annular spacers of resilient material; whereby when in operation said carriage is activated in the forward direction said protective sleeve assembly is withdrawn a predetermined distance from said pressure tube; and when said carriage is reversed in direction, said magazine is activated and an annular spacer is deposited between said pressure tube and said calandria tube.
Rather than installing the fuel channel annular spacers or garter springs once the new pressure tubes have been replaced in the calandria tubes, the present invention loads the annular spacers onto the new replacement pressure tubes outside of the reactor prior to replacement. These are placed in a unique magazine which is adapted to fit over the pressure tube and be ~~4~~~~
coupled by means of a threaded end to a protective plastic sleeve.
The other end of the plastic sleeve is coupled to a cone shaped nose portion. To balance the weight of the nose portion a counterweight, which is directed into the pressure tube by rollers, is used. The counterweight lies within one end of the replacement pressure tube. On the other end of the pressure tube is an end fitting which remains on the pressure tube once it is placed in the calandria tube.
A lifting device is used to move (one at a time), each of the entire protective sleeve pressure tube assemblies through the respective lattice tube openings in the reactor wall into each of the respective calandria tubes.
Once the protective sleeve assembly along with pressure tube end fitting is in place within the calandria tube, the travel tube which houses a carriage, is moved into a lattice tube extension sleeve which fits within a lattice tube in the calandria tube opening on the opposite side of the reactor. The carriage is then activated by an air motor coupled to a chain drive. The carriage then grasps the nose cone which is coupled to the protective sleeve assembly. The carriage moves away from the reactor wall and removes the protective sleeve from the newly replaced pressure tube. By this procedure, scoring is substantially reduced.
As the protective plastic sleeve is removed, fuel channel annular spacers are deposited at predetermined intervals along the pressure tube in a manner hereinafter described.
The predetermined positioning of the fuel channel annular spacers on the pressure tubes is determined by a series of 204~~j~
stop blocks which can rotatably be moved in and out of the travel tube which houses the carriage. The carriage is equipped with a retractable stop and a fixed stop.
As the carriage moves outwardly from the reactor wall by means of a chain drive and air motor, it abuts the first stop block with the retractable stop and then travels along until the fixed stop comes to rest against the stop block. The carriage is then reversed in direction, and presses the plastic protective sleeve coupled to the magazine and nose cone, back into the calandria tube, The distance travelled in reverse is predetermined by the length of the stop block and the gap between the fixed stop and the retractable stop.
The magazine which holds the four fuel channel annular spacers is comprised of an inner sleeve and an outer sleeve. The inner sleeve has friction bands on its inner cylindrical surface which cause the inner sleeve to remain in place on the pressure tube while the outer sleeve moves rearwardly when the carriage is in reverse. As the outer sleeve moves rearwardly, a fuel channel annular spacer is rolled between the inner sleeve and the outer sleeve and finally deposited on the pressure tube.
Thereafter, an operator removes the stop block from the travel tube of the carriage and the carriage moves in the forward direction until the next stop block is encountered. Each successive stop block in the path of the carriage is of successively shorter length. This determines the distance of rearward travel of the carriage.
The reason for increased reverse travel at each successive stop block is as follows. Within the magazine in the 2~~18~~
outer sleeve are a series of internal circumfe.rential grooves.
Typically there are four, but any number can be constructed depending upon the number of spacers required to be placed on the pressure tube. These grooves are placed approximately an inch apart. For that reason, it is necessary for the outer sleeve to travel rearwardly approximately an inch further each successive time that a fuel channel annular spacer is to be deposited.
Once the final .fuel channel annular spacer is deposited the carriage moves the protective sleeve assembly along with the nose cone and the magazine out of the calandria tube and off of the pressure tube and the operation is complete. The protective sleeve and nose cone and reloaded magazine are then placed on another replacement pressure tube which is destined to fit through a second calandria tube opening in the right hand reactor wall and the process is again repeated.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the invention will be further described in conjunction with the following drawings wherein:
Figure 1 is a schematic diagram of a nuclear reactor portion of a nuclear power plant;
Figure 2 is a detail (partially in section) of a conventional apparatus used to insert a protective tube assembly and replacement pressure tube into a calandria tube;
Figure 3 is a detail in sectional elevation of the carriage retracting tool and stop block mechanism for withdrawing the protective tube assembly from the calandria tube;
figure 4 is a view similar to Figure 3 but to a larger 204~8~2 scale;
Figure 5 is a perspective view of the magazine;
Figure 6 is a longitudinal section of the magazine and protective tube assembly in the stationary position on the pressure tube;
Figure 7 is a view similar to Figure 6 wherein the carriage has moved in reverse; and Figure 8 is a perspective view of a magazine loading tool.
Figure 1 shows a schematic view of the internal vault of a nuclear reactor; the reactor vault 1 is surrounded by left and right thick walls 2 and 2A, often referred to as end shields. A
series of horizontally disposed calandria tubes 3 run from sidewall to sidewall. The reactor vault is filled with a heavy water moderator 4 which surrounds the calandria tubes 3. The heavy water moderator 4 is circulated by a pump (not shown) through a heat exchanger (not shown) and then returned to the reactor vault, in a conventional fashion.
Horizontally disposed within each of the calandria tubes 3 are pressure tubes 5 in which fuel bundles 6 are placed. The fuel bundles are comprised of pencil like pelleted natural uranium. Heavy water coolant 7 is pumped through the inside of the pressure tubes, also known as fuel channels, in a usual manner.
Typically, in a Candu* reactor, fresh fuel is remotely placed in one end of a fuel channel while a simultaneous operation at the other end removes spent fuel. Since the flow path of the *Trade-mark 24~185~
heavy water coolant 7 occurs in alternating directions from channel to channel, fuel loading and removal occurs at alternating ends of the reactor. The fuel loading and removal operations are (unlike most other reactors) performed while the reactor is on power. These operations are carried out by remote operated machines because the radiation fields, during reactor operation, are too high for personnel to access the ends of the fuel channels.
During pressure tube replacement the worn pressure tubes 5 are removed from the calandria tubes 3.
Figure 2 shows a loading/insertion tool 40 at the right hand side of the reactor. Within the reactor, is shown the calandria tube 3 and the calandria tube opening 3a in the end wall 2A which is surrounded by a permanently embedded lattice tube 44, having an enlarged diameter at the outer side. A loading/
insertion tool 40 of a known type is used to insert a pressure tube 5 and a protective plastic outer sleeve 13 assembly through opening 3a into the calandria tube 3.
Turning briefly to Figure 3, one notes that in both the right hand side of the reactor end wall 2A and the left hand side of the reactor bounded by wall 2, the calandria tube openings 3A
are surrounded by a permanently embedded circular lattice tube 44 to provide ready access to the calandria tube 3 during pressure tube 5 replacement. Lattice tube extension sleeve 45 is fixedly connected to the lattice tube 44, in a conventional manner, as shown in Figures 3 and 4. Prior to insertion of the pressure tube into the calandria tube a protective sleeve assembly is assembled together. A nose cone 14 is attached to one end of the protective 2~~~~~~
plastic outer sleeve 13. threadedly mounted to the rear of the plastic sleeve 13 is a magazine 10. To the right of the magazine 10 and at the end of the pressure tube 5, an end fitting 43 is permarnently attached to pressure tube 5.
The loading insertion tool 40 has a suspended carriage 38 which supports the end fitting 43 by an end fitting carriage portion 42. A pressure tube support roller 39 supports pressure tube 5 and its protective plastic sleeve 13. Once the pressure tube 5, protective plastic sleeve 13, magazine 10, end fitting 43 10 and nose cone 14 are assembled into a protective sleeve assembly, the assembly is moved by the loading insertion tool to the left through the calandria tube opening 3A into the calandria tube 3.
After the pressure tube is inserted in the calandria tube, end fitting 43 is adapted to sit within opening 3a within lattice tube 44 and is fixedly secured therein in a known manner.
In Figure 3 the protective sleeve assembly is shown in place in the calandria tube 3a. The protective sleeve 13, pressure tube 5, magazine 10 and nose cone 14 have been inserted as shown in Figure 2 from the left side of the vault through the calandria tube opening 3A.
As seen in Figure 3 the nose cone 14 is attached to a nose cone counterweight 15 having rollers 37. The counterweight 15 extends rearwardly from the nose cone 14 into the pressure tube 5, The counterweight 15 is necessary to counter the weight of the nose cone 14 when the total assembly is being placed into the calandria tube.
Shown on the left hand side of the reactor wall 2 in Figure 3 is a protective sleeve assembly removal tool. Once the 20~185~
protective sleeve assembly is in place within the calandria tube 3, this protective sleeve assembly removal tool is moved into position. The removal tool consists essentially of a carriage 47 within a travel tube 16 (see particularly Figure 4). Travel tube 16 is inserted within lattice tube extension sleeve 45, and the latter is locked in place within lattice tube 44 in a conventional manner. The opening 3A in wall 2 is similar to that in wall 2A in that it is smaller at the reactor side than the outer side of wall 2. Travel tube 16, after being inserted in lattice tube extension sleeve 45, is locked in place therein by means of a locking ring 45A. Carriage 47 is supported within travel tube 16 by means of a plurality of rollers 37. Rollers 37 are adapted to position the carriage 47 within the center of travel tube 16.
Carriage 47 is arranged for reciprocal motion within travel tube 16. A pair of endless chains 46 are arranged longitudinally on either side of the inside of the travel tube 16 such that they are diametrically apart, permitting carriage 47 to move between them. Carriage 47 is drivingly connected to the chains 46 by means of a cross-bar (not shown). The chains are moved by means of an air motor (not shown), which is located at the outboard end of travel tube 16. The air motor, through a known gear arrangement drives the endless chains 46 by an outer sprocket 48A. The endless chains 46 turn around independent sprockets 48, one of which is mounted for each chain to each side of the travel tube 16, close to the reactor wall 2. By activating the air motor (not shown) in either direction, the carriage can be moved to the left and to the right, hereinafter kndwn as forward and rearward, within travel tube 16.
Carriage 47 has a carriage grasp 27 which automatically secures the nose cone 14 of the protective sleeve assembly when the carriage is activated into position.
In Figure 3 on the right hand side of the protective sleeve 13 and adjacent end fitting 43, (which is located at the right side of pressure tube 5), is a series of four fuel channel annular spacers 9 located within magazine 10.
Magazine 10 will be more clearly shown in drawings 5, 6 and 7, later to be described. Carriage 47 has a retractable front carriage stop 28 and a fixed carriage stop 29. A series of stop blocks 30, 31, 32 and 33, of successively shorter lengths, are located along a common shaft schematically shown at 34, adjacent travel tube 16. Openings 16B are located along the travel tube and allow an operator, by rotation of the control handle 35, to rotate stop blocks 30 through 33 into and out of travel tube 16.
Turning to Figure 5, a perspective view of the fuel channel annular spacer magazine 10 is shown looking at the trailing end. The magazine has an outer sleeve 17 and an inner sliding sleeve 18. Figure 5, for the sake of illustration, shows the inner sleeve 18 moved forwardly somewhat of the outer sleeve 17. In a preferred embodiment, the magazine has four internal grooves 20. Only three of these grooves are illustrated in Figure 5 and one of the grooves has already been fitted with a fuel channel annular spacer 9. Normally, once all of the grooves 20 of the magazine 10 have been loaded with fuel channel annular spacers 12a 9 in preparation for deposit along replacement pressure tube 5, the inner sleeve 18 and the outer sleeve 17 trailing ends (18A, 17A, respectively as shown in Figures 6 and 7) are adjacent one another, thereby retaining 2~4~~~2 the :Fuel channel annular spacers 9 prior to deposit.
In a preferred embodiment the outer sleeve is 12.72'°
long and the inner sleeve is 6.44" long. There is an annular gap between the two sleeves of .15". The outer sleeve is equipped with a circumferential outer guide ring 19 vahich is adapted to fit closely to the inner walls of calandria tube 3. The outer sleeve 17, adjacent one end, includes four internal circumferential grooves 20, which are adapted to hold the fuel channel annular spacers 9, three of which only are shown in Figure 5 for the sake of clarity.
~s can be seen in Figure 5, the fuel channel annular spacer 9 is comprised of a coiled spring. The magazine outer sleeve 17 is equipped with viewing holes 21 which register with each of the grooves 20. This allows the operator to see if the coiled springs are in place before threadedly attaching the magazine 10 on the protective sleeve 13. On the forward end of the outer sleeve 17 are three equally circumferentially spaced open-ended slots, the top one of which is shown at 23, which measure 8.56" long and 2.03" wide, in a preferred embodiment.
The inner sleeve 18 is equipped with three corresponding segmented equally circumferentially spaced protruding nylon motion limiting stop lugs, the top one of which is shown at 24, protruding through slot 23. Lugs 24 cooperate with slots 23 and prohibit the inner sleeve 18 from sliding rearwardly out of the outer sleeve 17 during the process of depositing the fuel channel annular spacers 9 on the pressure tubes 5. The slotted forward end of the outer sleeve 17 is equipped with a female internal thread which is adapted to threadedly engage the threaded end of the protective sleeve 13.
Figures 6 and 7 are sectional views of the magazine connected to the protective sleeve 13 surrounding a pressure tube 5. Figure 6 is shown in the condition of Figure 3 but with the calandria tube 3 removed for clarity. In Figure 6 the right hand end of the inner sleeve 18 (the trailing end), shown as 18A and the right hand end of the outer sleeve 17 shown as 17A (the trailing end), terminate at approximately the same point.
10 In Figure 7, however, the trailing end 17A of outer sleeve 17 has been pushed rearwardly beyond the trailing end 18A of the inner sleeve 18, thus being in a condition to allow the deposit of a fuel channel annular spacer 9 onto pressure tube 5, as will be explained more fully hereinafter.
In Figures 6 and 7 the pressure tube protective sleeve 13 is bonded to a plastic connector 12 which has a male thread 26 adapted to engage the female thread 26A of outer sleeve 17 of magazine 10. The inner sleeve 18 shown as 18A
in Figures 6 and 7 is equipped with two nylon friction rings 25 which are resiliently forced inwardly by leaf-springs 25A.
These rings 25 sit firmly in contact with pressure tube 5. In Figures 6 and 7 two friction rings 25 are shown, however, in a preferred embodiment three friction rings 25 can be used.
Figure 8 shows a tool for serially loading fuel channel annular spacers 9 into the magazine 10. The tool has a spacer receiving nose 22B and a shoulder stop 22A. The nose 14a 22B is inserted into the magazine until a spacer 9 is received in a groove 20, whereupon the tool 22 is withdrawn, the spacer being drawn over the nose 22B.
204~8~2 OPERATION OF THE INVENTION
The operation o.f the invention will be described hereinafter.
A worn pressure tube 5 has been removed from a calandria tube 3, leaving openings 3A in the right and left walls (end shields) of the reactor open. A protective tube assembly holding the pressure tube 5 is first assembled at the right hand side of the reactor. Firstly the magazine 10 is loaded with four fuel channel annular spacers 9 with the help of the loading tool 22.
Once loaded, the trailing ends (17A and 18A, respectively), of outer sleeve 17 and inner sleeve 18 of the magazine 10 are adjacent one another. Magazine IO is then threadedly attached to connector 12 which is fixedly bonded to protective plastic sleeve 13. The protective plastic sleeve 13 is already fixedly attached to its nose cone 14 and the counterweight 15.
Protective plastic sleeve 13 coupled with magazine 10 is then pushed commencing at the magazine end onto a new replacement pressure tube 5. Near the end of pressure tube 5, adjacent the magazine Z0, an end fitting 43 is connected to the pressure tube 5.
The loading insertion tool 40 (Fig 2) lifts the complete protective tube assembly, housing the pressure tube 5 with its end fitting 43 into position near opening 3A of calandria tube 3 at the right hand side of the reactor. Thereafter, the complete assembly is moved through the calandria tube opening 3A, being guided by the nose cone 14 until the nose cone 14 .Lies within the left hand reactor wall 2 (see Fig. 3). At this point in the 2~4~~~~
operation, the assembly can move no further to the left as the end fitting 43 is in position within wall 2A within lattice tube 44 and then is secured in a conventional manner into the wall 2A of the reactor.
As shown in Figures 3 and 4, after the end fitting 43 is connected to the right hand wall 2A of the reactor, a lattice tube extension sleeve 45 is fitted into the lattice tube 44 in calandria tube inlet 3A in the left hand wall 2 of the reactor.
Travel tube 16, with carriage 47 therein, is then moved into position and inserted into lattice tube extension sleeve 45 and locked therein by means of locking ring 45A. The air motor mentioned above is then activated such that the chains 46 move the carriage 47 rearwardly within travel tube 16 into a position such that the carriage grasp 27 latches onto nose cone 14 of the protective tube assembly. The protective tube assembly removal tool is then in a position to withdraw the protective sleeve 13 off of replacement pressure tube 5 and out of calandria tube 3, while depositing fuel channel annular spacers 9 in predetermined positions on pressure tube 5 as hereinafter described.
The air motor by a known gear arrangement, reverses the direction of the carriage 47 such that the carriage 47 moves forwardly away from the wall 2 of the reactor within travel tube 16.
When retractable carriage stop 28 of carriage 47 strikes the first stop block 30 it retracts downwardly permitting the carriage to continue its forward motion until fixed stop 29 abuts stop 30. Thereafter the air motor is activated to move the carriage in the rearward direction a distance °'X" which in this 2418 ~~
instance is 1.38" as shown in Figure 4. The distance "X" is the dirt<~nce between the right hand side of stop 28 and the left hand side of stop block 30. The rearward movement of the carriage 47 cause s nose cone 14, counterweight 15, protective sleeve 13, and outer sleeve 17 of the magazine 10 to move in the reverse direction towards the right wall 2A of the reactor (see now Figs.
6 & 7). During this rearward motion, however, friction bands 25 maintain inner sleeve 18 of magazine 10 in the same position on pressure tube 5. As the outer sleeve 17 of magazine 10 moves rearwardly with respect to the inner sleeve 18 of magazine 10, the fuel channel annular spacers 9 roll in the annular space between the outer sleeve 17 and the inner sleeve 18 until a first spacer, the one that was originally in the groove 20, closest to the trailing end of the magazine, falls off of the trailing end 18A of the inner sleeve 18 and is deposited onto the pressure tube 5, where its springing action grips the pressure tube 5.
After the fuel channel annular spacer 9 is deposited on pressure tube 5 and the carriage retractable stap 28 abuts stop block 30 at its left hand side, the air motor stalls, signalling the carriage movement to be reversed and to move in a forward direction. To permit the carriage 47 to continue travelling in the forward direction (see Fig. 3), the stop block 30 is retracted from travel tube 16 by operating handle 35, located near the outboard end of the travel tube 16. Stop block 30 remains retracted out of travel tube 16 until the carriage 47 and its stop 29 have cleared the position of stop block 30r after which block is returned to the original position in travel tube 16. Since all of the stop blocks are connected to a common shaft 34, blocks ~o4~s~~
31, 32 and 33 are also returned to travel tube 16 when block 30 is returned.
As the carriage 47 engages the second stop block 31, the first: retractable stop 28 moves downwardly, out of the way, and the carriage continues along until block 31 is contacted by fixed stop 29. The distance "X" in this position is 2.38" as opposed to 1.38" as block 31 is of smaller dimension. The carriage 47 is then activated in the reverse direction, as before. The distance of 2.38" allows the outer sleeve 17 of the magazine 10 to travel an extra inch rearwardly and eject a second fuel channel annular spacer 9 on pressure tube 5.
Each time the carriage 47 moves in the forward direction the trailing ends 17A and 18A of outer and inner sleeves, (17,18) respectively, of magazine 10, come back into a position as shown in Figure 6, the trailing end 18A of inner sleeve 18 being unable to move rearwardly of the trailing end 17A of outer sleeve 17 because of the limiting stop lugs 24 which abut on the closed ends of slots 23. Although friction rings 25 continue to exert pressure on pressure tube 5 in either dire ction of movement, the forward pulling force of the carriage 47 overcomes this friction.
However, when the carriage 47 moves in the rearward direction the lugs 24 are free to move towards the left relative to the slot 23 of outer. sleeve 17 of magazine 10, and the friction rings 25 prevent rearward movement of the inner sleeve 18.
Each time the carriage 47 moves forwardly, the fuel channel annular spacers 9 remaining in the magazine 10, roll back to their original positions in their respective grooves 20. As before, handle 34 is activated to remove block 31 from travel tube 16, to allow the carriage 47 to clear block 31 and then the blocks 30, 31, 32 and 33 are returned into the travel tube 16.
The sequence repeats itself for the deposit of the remaining two fuel channel annular spacers 9 on pressure tube 5.
As before these distances are controlled by dimensions of stop blocks 32, 33 and as aforementioned the distance between the blocks 30, 31, 32, 33 determines the placement of the spacers 9.
In a preferred embodiment, the distance the carriage moves in reverse after striking stop block 32 is 3.312°' and after striking stop block 33 the distance is 4.312".
After the final fuel channel annular spacer 9 is deposited on the pressure tube 5, the carriage 47 continues to move forwardly towards the outboard end of travel tube 16 until the nose cone 14, counterweight 15, protective sleeve 13 and magazine IO (now empty) are completely removed from the pressure tube 5.
The nose cone 14, counterweight 15, protective sleeve 13 and magazine 10 are then removed from travel tube 16, along with the carriage 47 and the former are returned to the right hand side of the reactor where another protective sleeve assembly is assembled for insertion into the next calandria tube 3. Meanwhile at the left hand side of the calandria tube at wall 2, other minor operations are completed, and thereafter a left hand wall 2 end fitting 43 is placed into lattice tube 44 to secure the left hand end of the pressure tube 5 within calandria tube 3.
At the right hand side of the reactor, the operation of pushing the protective sleeve 13 onto a second replacement pressure tube 5 is undertaken. Once again the assembly begins 2~~1~~~
with the magazine 10 being loaded with spacers 9 using the loading tool 22 and threadedly engaging the magazine 10 on the end of protective sleeve 13. Thereafter a new protective sleeve assembly, housing a replacement pressure tube 5, is loaded through another opening 3A in the right hand wall 2A of the reactor into a second calandria tube 3 and the process is repeated until all of the pressure tubes within the reactor which require replacement, are replaced.
It will be seen from the foregoing that the fuel channel annular spacers 9 are positioned as required with a minimal amount of operator exposure to radio active contamination, and at precise predetermined locations along the pressure tube.
Although a particular embodiment of the invention is illustrated, it is understood that many variations are possible without departing from the spirit of the invention.
After the fuel channel annular spacer 9 is deposited on pressure tube 5 and the carriage retractable stap 28 abuts stop block 30 at its left hand side, the air motor stalls, signalling the carriage movement to be reversed and to move in a forward direction. To permit the carriage 47 to continue travelling in the forward direction (see Fig. 3), the stop block 30 is retracted from travel tube 16 by operating handle 35, located near the outboard end of the travel tube 16. Stop block 30 remains retracted out of travel tube 16 until the carriage 47 and its stop 29 have cleared the position of stop block 30r after which block is returned to the original position in travel tube 16. Since all of the stop blocks are connected to a common shaft 34, blocks ~o4~s~~
31, 32 and 33 are also returned to travel tube 16 when block 30 is returned.
As the carriage 47 engages the second stop block 31, the first: retractable stop 28 moves downwardly, out of the way, and the carriage continues along until block 31 is contacted by fixed stop 29. The distance "X" in this position is 2.38" as opposed to 1.38" as block 31 is of smaller dimension. The carriage 47 is then activated in the reverse direction, as before. The distance of 2.38" allows the outer sleeve 17 of the magazine 10 to travel an extra inch rearwardly and eject a second fuel channel annular spacer 9 on pressure tube 5.
Each time the carriage 47 moves in the forward direction the trailing ends 17A and 18A of outer and inner sleeves, (17,18) respectively, of magazine 10, come back into a position as shown in Figure 6, the trailing end 18A of inner sleeve 18 being unable to move rearwardly of the trailing end 17A of outer sleeve 17 because of the limiting stop lugs 24 which abut on the closed ends of slots 23. Although friction rings 25 continue to exert pressure on pressure tube 5 in either dire ction of movement, the forward pulling force of the carriage 47 overcomes this friction.
However, when the carriage 47 moves in the rearward direction the lugs 24 are free to move towards the left relative to the slot 23 of outer. sleeve 17 of magazine 10, and the friction rings 25 prevent rearward movement of the inner sleeve 18.
Each time the carriage 47 moves forwardly, the fuel channel annular spacers 9 remaining in the magazine 10, roll back to their original positions in their respective grooves 20. As before, handle 34 is activated to remove block 31 from travel tube 16, to allow the carriage 47 to clear block 31 and then the blocks 30, 31, 32 and 33 are returned into the travel tube 16.
The sequence repeats itself for the deposit of the remaining two fuel channel annular spacers 9 on pressure tube 5.
As before these distances are controlled by dimensions of stop blocks 32, 33 and as aforementioned the distance between the blocks 30, 31, 32, 33 determines the placement of the spacers 9.
In a preferred embodiment, the distance the carriage moves in reverse after striking stop block 32 is 3.312°' and after striking stop block 33 the distance is 4.312".
After the final fuel channel annular spacer 9 is deposited on the pressure tube 5, the carriage 47 continues to move forwardly towards the outboard end of travel tube 16 until the nose cone 14, counterweight 15, protective sleeve 13 and magazine IO (now empty) are completely removed from the pressure tube 5.
The nose cone 14, counterweight 15, protective sleeve 13 and magazine 10 are then removed from travel tube 16, along with the carriage 47 and the former are returned to the right hand side of the reactor where another protective sleeve assembly is assembled for insertion into the next calandria tube 3. Meanwhile at the left hand side of the calandria tube at wall 2, other minor operations are completed, and thereafter a left hand wall 2 end fitting 43 is placed into lattice tube 44 to secure the left hand end of the pressure tube 5 within calandria tube 3.
At the right hand side of the reactor, the operation of pushing the protective sleeve 13 onto a second replacement pressure tube 5 is undertaken. Once again the assembly begins 2~~1~~~
with the magazine 10 being loaded with spacers 9 using the loading tool 22 and threadedly engaging the magazine 10 on the end of protective sleeve 13. Thereafter a new protective sleeve assembly, housing a replacement pressure tube 5, is loaded through another opening 3A in the right hand wall 2A of the reactor into a second calandria tube 3 and the process is repeated until all of the pressure tubes within the reactor which require replacement, are replaced.
It will be seen from the foregoing that the fuel channel annular spacers 9 are positioned as required with a minimal amount of operator exposure to radio active contamination, and at precise predetermined locations along the pressure tube.
Although a particular embodiment of the invention is illustrated, it is understood that many variations are possible without departing from the spirit of the invention.
Claims (19)
1. A system for depositing fuel channel annular spacers between pressure tubes and calandria tubes in a nuclear reactor comprising in combination:
a protective sleeve assembly adapted to surround a replacement pressure tube and adapted to pass through a calandria tube;
said protective sleeve assembly including a magazine operable to deposit fuel channel annular spacers along a pressure tube to separate said pressure tube from said calandria tube;
means for inserting said protective sleeve assembly and said replacement pressure tube into said calandria tube from one side of said reactor;
a protective sleeve removal tool adapted to remove said protective sleeve assembly from said pressure tube and said calandria tube from the opposite side of said reactor from which said protective sleeve assembly is inserted;
said protective sleeve removal tool including a magazine actuating means operable to actuate said magazine to serially deposit fuel channel annular spacers in spaced relation along said pressure tube while said protective sleeve assembly is being removed therefrom.
a protective sleeve assembly adapted to surround a replacement pressure tube and adapted to pass through a calandria tube;
said protective sleeve assembly including a magazine operable to deposit fuel channel annular spacers along a pressure tube to separate said pressure tube from said calandria tube;
means for inserting said protective sleeve assembly and said replacement pressure tube into said calandria tube from one side of said reactor;
a protective sleeve removal tool adapted to remove said protective sleeve assembly from said pressure tube and said calandria tube from the opposite side of said reactor from which said protective sleeve assembly is inserted;
said protective sleeve removal tool including a magazine actuating means operable to actuate said magazine to serially deposit fuel channel annular spacers in spaced relation along said pressure tube while said protective sleeve assembly is being removed therefrom.
2. A system as claimed in claim 1 wherein said protective sleeve assembly includes a plastic protective sleeve, a nose cone and a counterweight;
said counterweight adapted to fit within a pressure tube.
said counterweight adapted to fit within a pressure tube.
3. A system as claimed in claim 1 wherein said means for inserting said assembly comprises a support carriage;
said support carriage adapted to direct said protective sleeve assembly and said pressure tube into a calandria tube opening in an end wall of a reactor.
said support carriage adapted to direct said protective sleeve assembly and said pressure tube into a calandria tube opening in an end wall of a reactor.
4. A system as claimed in claim 1 wherein said protective sleeve removal tool includes a carriage adapted for forward and rearward movement within a travel tube;
said travel tube adapted to cooperate with an opening in a nuclear reactor end wall.
said travel tube adapted to cooperate with an opening in a nuclear reactor end wall.
5. A system as claimed in claim 4 wherein said magazine actuating means includes a plurality of stop blocks;
said stop blocks adapted for movement into and out of said travel tube;
said stop blocks operable to limit the movement of said carriage in the rearward and forward directions.
said stop blocks adapted for movement into and out of said travel tube;
said stop blocks operable to limit the movement of said carriage in the rearward and forward directions.
6. A system as claimed in claim 5 wherein said stop blocks are of different lengths, the length of each being lessor than the adjacent stop blocks as said blocks are located further away from said nuclear reactor wall;
said stop blocks being located along said travel tube at predetermined distances, said distances corresponding to positions, that said annular spacers are deposited on said pressure tubes.
said stop blocks being located along said travel tube at predetermined distances, said distances corresponding to positions, that said annular spacers are deposited on said pressure tubes.
7. A system as claimed in claim 6 wherein the length of said stop blocks determines the distance said carriage moves rearwardly, wherein in operation;
said rearward movement of said carriage is operable to actuate said magazine to deposit a fuel channel annular spacer on said pressure tube.
said rearward movement of said carriage is operable to actuate said magazine to deposit a fuel channel annular spacer on said pressure tube.
8. A system for depositing fuel channel annular spacers between pressure tubes and calandria tubes in a nuclear reactor comprising:
a carriage adapted for two-directional movement within an elongate travel tube;
said elongate travel tube being adapted to be aligned with the calandria tube in one sidewall of said reactor;
means for controlling movement of said carriage predetermined distances in a forward direction and a rearward direction;
said carriage including a grasping mechanism adapted to move a protective sleeve assembly within a calandria tube;
said protective sleeve assembly comprising a graspable nose cone, a protective sleeve, and an annular spacer magazine;
said protective sleeve and said magazine being of annular configuration and adapted to fit between said pressure tubes and said calandria tubes;
23a said annular spacer magazine being adapted to hold a plurality of annular spacers of resilient material;
whereby when in operation said carriage is activated in the forward direction said protective sleeve assembly is withdrawn a predetermined distance from said pressure tube; and when said carriage is reversed in direction, said magazine is activated and an annular spacer is deposited between said pressure tube and said calandria tube.
a carriage adapted for two-directional movement within an elongate travel tube;
said elongate travel tube being adapted to be aligned with the calandria tube in one sidewall of said reactor;
means for controlling movement of said carriage predetermined distances in a forward direction and a rearward direction;
said carriage including a grasping mechanism adapted to move a protective sleeve assembly within a calandria tube;
said protective sleeve assembly comprising a graspable nose cone, a protective sleeve, and an annular spacer magazine;
said protective sleeve and said magazine being of annular configuration and adapted to fit between said pressure tubes and said calandria tubes;
23a said annular spacer magazine being adapted to hold a plurality of annular spacers of resilient material;
whereby when in operation said carriage is activated in the forward direction said protective sleeve assembly is withdrawn a predetermined distance from said pressure tube; and when said carriage is reversed in direction, said magazine is activated and an annular spacer is deposited between said pressure tube and said calandria tube.
9. A system as claimed in claim 8 including a means to load said protective sleeve assembly within said calandria tube by guiding said assembly through a calandria tube inlet in an opposite sidewall of said reactor;
said protective sleeve and said magazine enveloping a pressure tube with an end fitting mounted thereon.
said protective sleeve and said magazine enveloping a pressure tube with an end fitting mounted thereon.
10. A system as claimed in claim 8 wherein said carriage is activated by an air motor, a pair of chains, a gear means, and a plurality of rotatably mounted sprockets.
11. A system as claimed in claim 8 wherein said means for controlling movement of said carriage predetermined distances in the fore and aft directions comprises:
a plurality of stop blocks which decrease in length as the distance between said stop blocks and said calandria tube inlet increases;
the number of said stop blocks being equal to the number of annular spacers to be deposited;
said blocks adapted to enter or exit said elongate travel tube and arranged along the same at predetermined distances;
and said carriage including a first retractable stop and a second fixed stop;
wherein in operation when said carriage strikes any one of said stop blocks in the forward direction, said retractable stop retracts and said carriage passes along said stop block until said fixed stop strikes one end of said stop block; and thereafter said carriage reverses direction until said retractable stop strikes an other end of said stop block during which time an annular spacer is deposited on said pressure tube;
thereafter, said stop block is temporarily withdrawn from said tube assembly and said carriage is activated in the forward direction until a second stop block is encountered.
a plurality of stop blocks which decrease in length as the distance between said stop blocks and said calandria tube inlet increases;
the number of said stop blocks being equal to the number of annular spacers to be deposited;
said blocks adapted to enter or exit said elongate travel tube and arranged along the same at predetermined distances;
and said carriage including a first retractable stop and a second fixed stop;
wherein in operation when said carriage strikes any one of said stop blocks in the forward direction, said retractable stop retracts and said carriage passes along said stop block until said fixed stop strikes one end of said stop block; and thereafter said carriage reverses direction until said retractable stop strikes an other end of said stop block during which time an annular spacer is deposited on said pressure tube;
thereafter, said stop block is temporarily withdrawn from said tube assembly and said carriage is activated in the forward direction until a second stop block is encountered.
12. A system as claimed in claim 8 wherein said annular spacer magazine comprises:
an inner sleeve and an outer sleeve;
said outer sleeve including a plurality of spaced apart circumferential internal grooves near a first end;
each of said grooves adapted to seat an annular spacer;
and said spacers being held in said grooves by the outer surface of said inner sleeve.
an inner sleeve and an outer sleeve;
said outer sleeve including a plurality of spaced apart circumferential internal grooves near a first end;
each of said grooves adapted to seat an annular spacer;
and said spacers being held in said grooves by the outer surface of said inner sleeve.
13. A system as claimed in claim 12 wherein a second end of said outer sleeve includes at least one open-ended slot:
said sleeve being threaded on the inner circumference with a female thread; and said outer sleeve being adapted to connect to a male thread on said protective sleeve.
said sleeve being threaded on the inner circumference with a female thread; and said outer sleeve being adapted to connect to a male thread on said protective sleeve.
14. A system as claimed in claim 13 wherein said inner sleeve includes at least one circumferential protruding lug;
said lug being adapted to cooperate with said slot on said outer sleeve;
said lug permitting movement of said inner sleeve towards a second end of said outer sleeve when said carriage is moved in the reverse direction, while limiting movement of said inner sleeve in the opposite direction, such that said inner sleeve does not extend further than said first end of said outer sleeve.
said lug being adapted to cooperate with said slot on said outer sleeve;
said lug permitting movement of said inner sleeve towards a second end of said outer sleeve when said carriage is moved in the reverse direction, while limiting movement of said inner sleeve in the opposite direction, such that said inner sleeve does not extend further than said first end of said outer sleeve.
15. A system as claimed in one of claims 12, 13 or 14 wherein said inner sleeve contains a plurality of spring biased annular friction rings;
said rings being adapted to fit securely around said pressure tubes such that when in operation, said carriage reverses direction, and pushes said protective sleeve assembly into said calandria tube, said inner sleeve maintains its position on said pressure tube, while said first end of said outer sleeve advances, thereby depositing an annular spacer on said pressure tube.
said rings being adapted to fit securely around said pressure tubes such that when in operation, said carriage reverses direction, and pushes said protective sleeve assembly into said calandria tube, said inner sleeve maintains its position on said pressure tube, while said first end of said outer sleeve advances, thereby depositing an annular spacer on said pressure tube.
16. A system as claimed in one of claims 12, 13 or 14 wherein said outer sleeve contains an outer circumferential guide ring;
said guide ring being adapted to fit snugly against the inner side of said calandria tube.
said guide ring being adapted to fit snugly against the inner side of said calandria tube.
17. A system as claimed in one of claims 12, 13 or 14wherein said outer sleeve contains a plurality of viewing holes;
said viewing holes being in alignment with said internal grooves.
said viewing holes being in alignment with said internal grooves.
18. A system as claimed in claim 11 comprising four stop blocks adjacent said travel tube, and four grooves in said first end of said outer sleeve;
each groove being adapted to hold an annular spacer; and said blocks being positioned from one another along said elongate travel tube the same distance as each of said annular spacers are deposited from one another along said pressure tube, wherein the distance in length of successive stop blocks is substantially equal to the distance between successive grooves on said outer sleeve of said magazine.
each groove being adapted to hold an annular spacer; and said blocks being positioned from one another along said elongate travel tube the same distance as each of said annular spacers are deposited from one another along said pressure tube, wherein the distance in length of successive stop blocks is substantially equal to the distance between successive grooves on said outer sleeve of said magazine.
19. A system as claimed in claim 18 wherein in operation, the distance which said carriage travels rearwardly, increases with each successive stop block encountered, and said outer sleeve of said magazine moves further rearwardly relative to said inner sleeve with each successive rearward movement of the carriage, thereby permitting successive annular spacers to be deposited on said pressure tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002041852A CA2041852C (en) | 1991-05-06 | 1991-05-06 | Garter spring magazine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002041852A CA2041852C (en) | 1991-05-06 | 1991-05-06 | Garter spring magazine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2041852A1 CA2041852A1 (en) | 1992-11-07 |
| CA2041852C true CA2041852C (en) | 1999-12-28 |
Family
ID=4147546
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002041852A Expired - Lifetime CA2041852C (en) | 1991-05-06 | 1991-05-06 | Garter spring magazine |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2041852C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5386444A (en) * | 1993-01-15 | 1995-01-31 | General Electric Company | Fuel rod loading apparatus |
| EP0650168A1 (en) * | 1993-10-25 | 1995-04-26 | General Electric Company | Method for preventing scratches on fuel rods during fuel bundle assembly |
-
1991
- 1991-05-06 CA CA002041852A patent/CA2041852C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2041852A1 (en) | 1992-11-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry | ||
| MKEX | Expiry |
Effective date: 20110506 |