CA1125928A - Radiation shielded movable work station apparatus - Google Patents
Radiation shielded movable work station apparatusInfo
- Publication number
- CA1125928A CA1125928A CA338,818A CA338818A CA1125928A CA 1125928 A CA1125928 A CA 1125928A CA 338818 A CA338818 A CA 338818A CA 1125928 A CA1125928 A CA 1125928A
- Authority
- CA
- Canada
- Prior art keywords
- station apparatus
- work station
- enclosure
- shell
- enclosures
- 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
Links
Classifications
-
- 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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- Monitoring And Testing Of Nuclear Reactors (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Described is a movable work station apparatus including travelling-hoist supported tools and a vertically and rotarywise movable frame-carried radiation-shielded enclosure, or gondola, for working personnel involved in tube-bundle-replacement tasks performed within the shell of a steam generator in a nuclear plant. The enclosure, or gondola, is divided and accommodates four upright workers in mutually facing pairs at opposite sides of a work-accommodating clearanceway observable and accessible from the gondola interior via lead glass windows and hand holes.
Described is a movable work station apparatus including travelling-hoist supported tools and a vertically and rotarywise movable frame-carried radiation-shielded enclosure, or gondola, for working personnel involved in tube-bundle-replacement tasks performed within the shell of a steam generator in a nuclear plant. The enclosure, or gondola, is divided and accommodates four upright workers in mutually facing pairs at opposite sides of a work-accommodating clearanceway observable and accessible from the gondola interior via lead glass windows and hand holes.
Description
~07~ or T~ ~rl~
m i~ inve~tion rel~tes to apparatus for e~ecting retubi~g of a steam generator ~n a nuclear power pla~t.
Nuclear reactor power plants utilize a steam gen-erator having a tube bundle to trans~er heat from a primary side reactor-heated-liquid to water on a secondary side to ~orm steam ~or dri~ing a ~urbines Condenser leaks ~n the power plant~ have caused clrculating water, which i~ often brackish, to ~ix with the secondary-side water in the ste2m generator, resulting in the build-up o~ undesirable chemical~
in the tube ~undle. Water ~reatment and blowdown have not completely protected the steam generator tubes from corrosio~
and leaksO As the ~umber o~ tubes subject to such leaks increases9 the desirabiIit~ o~ replacement or repair of the steam generator increases. Since removal of a steam g~nerator in its entirety irom a nuclear power plant requlres tearing out a large portion of a reinforced co~crete conta~nment vessel, replacement of such generator in toto becomes time . . -,, .,, ., ~ i. ............ , . . ., , :
- . . .
:
47,763 consuming, expensive~ and therefore undesirable.
SUMMARY OF THE IN~ENTION
The present invention is related in general to the replacement of the tube bundle in a steam generator in a nuclear power plant and more particularly to a work station apparatus movable within the shell of such steam generator to transport and radiation-protect workers during execution of certain operational stages involved in the tube bundle replacement. In its preferred form as presently con-templated such work station apparatus includes a verticallytransportable support frame in which is disposed a removable enclosure or gondola assembly that is constructed and arranged to accommodate four construction workers in an upright attitude in pairs at opposite sides of a vertical clearanceway observ-able from the interior of the housing through the medium of lead glass windows and accessible for work performance by hand holes in the enlcosure. In general, the workpiece ob~ects to which the work effort is to be directed will be located immediately beneath the vertical clearanceway ~
and the enclosure assembly is so constructed that the workers therein remain in a vertical and upright attitude during their performance of work tasks, thereby ma~imizing the distance between the workpiece ob~ects which may be slightly radioactive and the more vulnerable reglons of the workers anatomy. To assist the workers in the performance of the tasks to be performed beneath the clearanceway a plurality of hoists on overhead carriages and cross-carriages are provided in the upper region of the clearanceway supported on suitable cross members for raising and lowering various ~0 tools us~d in th~ clearanceway. All of the foregoin~ com-
m i~ inve~tion rel~tes to apparatus for e~ecting retubi~g of a steam generator ~n a nuclear power pla~t.
Nuclear reactor power plants utilize a steam gen-erator having a tube bundle to trans~er heat from a primary side reactor-heated-liquid to water on a secondary side to ~orm steam ~or dri~ing a ~urbines Condenser leaks ~n the power plant~ have caused clrculating water, which i~ often brackish, to ~ix with the secondary-side water in the ste2m generator, resulting in the build-up o~ undesirable chemical~
in the tube ~undle. Water ~reatment and blowdown have not completely protected the steam generator tubes from corrosio~
and leaksO As the ~umber o~ tubes subject to such leaks increases9 the desirabiIit~ o~ replacement or repair of the steam generator increases. Since removal of a steam g~nerator in its entirety irom a nuclear power plant requlres tearing out a large portion of a reinforced co~crete conta~nment vessel, replacement of such generator in toto becomes time . . -,, .,, ., ~ i. ............ , . . ., , :
- . . .
:
47,763 consuming, expensive~ and therefore undesirable.
SUMMARY OF THE IN~ENTION
The present invention is related in general to the replacement of the tube bundle in a steam generator in a nuclear power plant and more particularly to a work station apparatus movable within the shell of such steam generator to transport and radiation-protect workers during execution of certain operational stages involved in the tube bundle replacement. In its preferred form as presently con-templated such work station apparatus includes a verticallytransportable support frame in which is disposed a removable enclosure or gondola assembly that is constructed and arranged to accommodate four construction workers in an upright attitude in pairs at opposite sides of a vertical clearanceway observ-able from the interior of the housing through the medium of lead glass windows and accessible for work performance by hand holes in the enlcosure. In general, the workpiece ob~ects to which the work effort is to be directed will be located immediately beneath the vertical clearanceway ~
and the enclosure assembly is so constructed that the workers therein remain in a vertical and upright attitude during their performance of work tasks, thereby ma~imizing the distance between the workpiece ob~ects which may be slightly radioactive and the more vulnerable reglons of the workers anatomy. To assist the workers in the performance of the tasks to be performed beneath the clearanceway a plurality of hoists on overhead carriages and cross-carriages are provided in the upper region of the clearanceway supported on suitable cross members for raising and lowering various ~0 tools us~d in th~ clearanceway. All of the foregoin~ com-
-2-ponents are in tu~n carried on a main support ~rame suspended from an overhead crane mounted atop a pedestal assembly restLng on an upper open end of the steam generator shell and made accessible for such mounting b~ cutaway o~ a cover portion of the steam generator shell in a pre~iously con ducted prelimlnary step involved in the overall retubing operation. When disposed in lowered work position, the ~rame-supported shielded working enclosure assembly is adapted to be turned about a central axis o~ the steam generator shell by virtue of suspenslon of such assembly by a rotary swivel and use o~ an array of wheels which may be effectuated to be brought into rolling engagement with ~he inner wall o~ -the ~` steam generator shell and operated manually to e~ect such a turning move~ent as may be desired~
BRIEF ~ESCRIPTION OF THE DRAWINGS
Figure 1 is a vertical perspective view of the tube-containing portion of a nuclear power plant steam gen-erator shown partially in section;
Fi~ure 2 is a vertical view partly in outline and partly in section showing a preferred embodiment of th~
present invention affiliated with the shell of a steam generator such as shown in Fig. 1 from which the tube bundle depicted in such Figure has been removed;
Figure 3 is a section view taken along the line III-III ~n Fig~ 2;
Figure 4 is a section view taken along the line IV-IV in Fig. 2;
Figure 5 is a perspective view in elevation showing details of a shielded enclosure embodied in the apparatus of the present invention;
BRIEF ~ESCRIPTION OF THE DRAWINGS
Figure 1 is a vertical perspective view of the tube-containing portion of a nuclear power plant steam gen-erator shown partially in section;
Fi~ure 2 is a vertical view partly in outline and partly in section showing a preferred embodiment of th~
present invention affiliated with the shell of a steam generator such as shown in Fig. 1 from which the tube bundle depicted in such Figure has been removed;
Figure 3 is a section view taken along the line III-III ~n Fig~ 2;
Figure 4 is a section view taken along the line IV-IV in Fig. 2;
Figure 5 is a perspective view in elevation showing details of a shielded enclosure embodied in the apparatus of the present invention;
-3-5 ~ 2 ~
Figure 6 is an elevation Vi8W, partly in outline and partly in section showing a manually operable means for ef~ecting turning mo~ement o~ the shielded work statiGn apparatus of the present invention when disposed within the shell o~ the steam generator; and Figure 7 is an elevation view3 partly in outline~
showing the crane assembly and upper support frame of this in-ventlon.
Referring to Fig. 1 in the drawings the steam generator 1 with which the movable work station apparatus of the present invention is i~tended to be employed ~or replacement of the tube bundle 23 therein typically includes a vertically orie~ted shell ~, the shell oomprising a lower cylindrical portion ~ and an upper cylindrical portion 79 larger in diameter than the lower portion 5 and a frustoco~-~: ical transition portlon 9 ~oining the lower and upper portions 5 and 7. A tube sheet 11 is disposed in the lower end o~ the ~` lower portion 5 of the shell and has a plurality of holes for accommodating the ends of U-shaped tubes 13 which extend upwardly from the tube sheet 11 and are closely packed to form the tube bundle 23 disposed ~ertically wlthin the lower portion 5 of the shell 3.
A hemispherical channel head 15 is fastened to the tube sheet 11 and has a divider plate 17 disposed therein, A primary fluid inlet nozzle 19 supplies heated affluent pri-mary fluid from a nuclear reactor core (not show~) to one portion of the channel head 15 and a discharge ~ozzle 21 is disposed in the channel head 15 to return the afflue~t pri-30 mary ~luid to such reactor core.
~Z~ 47,763 A plurality of support plates 25 are disposedthroughout the tube bundle 23 to support the tubes 13 at various locations along their length to reduce flow-induced vibrations. Anti-vibration bars 27 are also disposed adjacent to the bends in the tubes 13 to prevent vibration in this portion of the tube bundle 23.
A wrapper or sleeve 29 is disposed between the tube bundle 23 and the shell 3 so as to form an annular space ~ ;
31 therebetweenO The upper part of the upper section 7 of the shell has been removed to gain access to the interior of the steam generator in preparation for removal and replace-ment of the tube bundle therein. Various components of the steam generator usually disposed in the upper section 7 of the shell 3 also have been removed from the steam generator as shown in Fig. l to provide access to the top of the sleeve encircling the tube bundle 23. The upper circular edge 3L~ of the upper portion 7 of the shell 3 will be smooth and even and rather precisely defined and will lie in a horizon-tal plane by virtue of a rather careful previous grinding, 20 cutting or machining operations previously referred to as preparatory to in situ tube bundle replacement.
~ 'ypical operation o~ the steam generator, which per ~e forms no part of the present invention, involves the ~low o~ heated primary fluid from a nuclear reactor core upwardly through the tube sheet 11 and one branch of the U-shaped tube bundle 23 and downwardly through the other branch of such tube bundle and back through the tube sheet 11 to the discharge nozzle 21, while secondary fluid above the tube sheet 11 and outside the tube bundle 23 becomes 30 heated for forming steam for conveyance by conduit means ~S~2~ 47,763 (not shown) to a turbine (not shown) operated by such steam.
Referring to ~g~. 2, 3, 4 and 5 in khe drawing, the present invention comprises an enclosure assembly including a pair of radiation-shielded worker enclosures 40 each of which is adapted to accommodate two workers (not shown) standing in upright attitudes. Each of the shielded enclo-sures 40 has wall portions made of relatively thick steel plate joined together as by weldments (not shown) and includes four separate sections, two upper sections 40Ul and 40U2 and 10 two lower sections 40Ll and 40L2 to facilitate set-up and knock-down of the enclosure when desired. The vertical walls of the enclosures 40 may be in the order of several inches thick, with a bottom wall of about four inches tllick, for example, and a top cover member 41 of something like a half inch thick or less, for example. Total height of each en-closure may be in the order of slightly less than eight feet, which affords ample height within the interior of the enclo-sure to accommodate the workers therein in their standing attitude, even while wearing hard hats as the case might be.
Each lower section 40Ll and 40L2 of the enclosures 40 is provided with a bottom-hinged sheet steel door 42 of flanged-edge construction suitably proportioned to permit the workers to enter and leave via entranceways in the forward walls of such enclosure sections in open, lowered, positlons of the doors as shown in the lower lefthand portion of fig.
5 affiliated with the enclosure section 40Ll. This is arrived at by providing hinges 43 at the lower horizontal edges of the doors 42 and provision of a manually operable latch 44 at the upper edge of the door for Securing same w~en closed.
Hinged retractable support arms 45 hold such worker entrance ~ 47,763 doors 42 in a horizontal attitude when opened. The front of each of the upper enclosure sections 40Ul and 40U2 is provided with a thick lead glass window 46 arranged to extend hori~ontally outward beyond the location of the forward vertical face of the lower housing section 40Ll, 40L2 and which has an inwardly e~tending lower portion con-structed and arranged to afford a downwardly-aimed view to working personnel withln such enclosure. Relatively thick .
lead glass windows 47 are provided also i.n the rear walls of upper enclosure sections 40Ul and 40U2 to afford additional observation locations to personnel within the enclosures 40.
Hand .holes 48 are provided in the upper housing or upper enclosure sections 40Ul and 40U2 beneath the observation windows 46 and 47 at front and rear to enable tools (not shown), for examplej located outside the enclosure to be manipulated by working personnel standing within such en-closures. The front of each enclosure 40 is wider than the rear and its side walls taper inwardly from front to rear to provide a configuration that nests conveniently ad~acent to the inner surface of the lower section 5 of the shell 3 of the steam generator l in absence of the tube bundle 23 being replaced.
The upper and lower sections of the shielded enclo-sures 40 are removable supported in support cage assemblies 50 made up of horizontal and verti.cal angle arm members welded together. Vertical guide rollers 51 are carried at the bottom of the support cage assemblies 50 at the rear of the working personnel enclosures 40 for vertical guiding ~operation with the inner wall of the lower ~ection 5 of the shell 3 of the steam generator l while such assembly is ~ ~2 ~ 47,763 being transported vertically through the interior of such shell section as during transport within the generator shell to and from a work site. The working enclosures 40 are so proportioned that when they are disposed within the interior of the low~er section 5 of the steam generator shell 3 as shown in ~g. 4, for example, they provide a vertical clear-q~ ~
anceway ~ therebetween~ such clearanceway affording a pathway for disposition, travel, and manipulation of tools (not shown) and/or workpiece parts (not shown) being manipulated or worked on. The support cage assemblies 50 for the two shieldedpersonnel enclosures 40 are mechanically connected through the medium of a supporting structure to be described subse~
quently.
The bottom portions of such support cage assemblies include a plurality of rubber tired wheels 52 constructed and arranged for circumferential rolling engagement with the inner surface of the lower shell section 5 of the steam generator 1 relative to turning mo~ement about the central axis ~ of such shell section. One of such wheels 52 affiliated with each enclosure 40 assembly is actuable by a pneumatic cylinder means (not shown) to a retracted position disposed out of engagement with the inner shell wall to prevent interference with vertical movement when desired. In addition, one of the wheels 52, in accord with the showing in figs. 4 and 6 is turnable manually b~ a hand wheel 54 from the interior of one of the enclosures 40 to effect turning movement of the interconnected enclosure 40 when desired. The operating mechanism for effecting such a turning movement of the one rubber tired wheel 52 is affiliated with a support frame 50 for the one enclosure 40 and includes for example a rotary ': .
5 ~
~7~763 shaft ~5 secured to the wheel 52 to turn therewith, a number o~ brackets 56 for 9upport of the wheel and for guiding turning movement of khe drive shaft 550 A right-angle gear dri~e mechanism 57 has a drive input ~haft 5g connected to the hand wheel 5~ and an output shaft 59 joined by a sui~able coupling 60 to the u~per end of the dri~e ~haft 55. The shaft 5~ connected to the hand wheel 54 will pass through a side wall of the respective en-closure ~0~
An air conditioning unit 90 with intake fil~er 9~ is pro~ided each one of the personnel enclosures ~0 mounted on ~he top cover member ~1 thereof ~or comfork and sa~ety of ~he personnel therein~
Each of the personnel enclosures ~0 is ~oined to an o~erhead horizontal suppor~ frame assembly 65 through the medium of respecti~e vertical interconnecting frame means 66. iThe horizontal support frame assembly 65 includes a pair o~ I-beam members 67 extending above the enclosures 40 across the clearanceway 92 kherebetweens Opposite ends o~ the I-beam members 67 are removably attached to the tops of the interconnect frame means 66 by means of plates 6~ and bolts 69. A pair of cross carriage tracks 70 o.f I~beam construct,ion are welded to the underside o~ the I-beam members 67 and extend widthwise of the enclo~ures 40 at opposite sides of the upper end of the clearanceway 924 A plurality of cross carriages 71, four being shown in Figo 3 for ex.~mple? are arranged for movement widthw~se of the enclosures ~0 along the tracks 70 through the medium of rollers 72 suppo~ted by brackets welded to the upper edge of the cross-carriage beams 71 at theîr opposite ends. Each of ~he cross-carriages 71 carries a power operated hoist 73 suspended from a re~
spective ~rolley ~;Z592~
74 roller-suppor~ed on ~he lower flange of the cross carriage beam 71; one such hoist 73 being shown in Fig. 2 and one such hoist being shown in Fig~ 3.
The entire assembly i~cluding the personnel en~
closure~ 40, support cages 50 g ~ertical in~erconnect ~rames 66, and horizon~al support frame 659 includ1ng the cross carriage tracks 71, hoist 73, etc~ is supported for vertical and rotary mo~ement about the central axis of the steam generator shell 3 on a swi~el hook 75 at the lower end o~ a travelling block 76. The block 76 i~ suppor~ed by multiple cable loops 77a from a sheave 77 formlng part of a crane assembly 7~ that includes a cable drum 79 and members ~1 forming a rectangular frame supporting such shea~e 77, motor ~0, and cable drum 79 for proper payout and reel-in of the cable to and from the shea~e 77 for rai~ing and lowering the travelling block 76 and the load supported thereby on the swirel hook 75 as shown in Figures 5 and 7. The crane assembly 7~ in ~urn is ~upported on a rectangular frame made up of horizontal I-beam members ~2 welded together at their corner~ a~d support,ed at such corners by vertical I beam columns ~3 secured to and ex-tending upwardly from a support ring ~5 which in turn finds support from mounting bracke~ assemblies ~6 dispo~sd immediately beneath the columns ~3 and carried on the upper rim edge 34 of the upper portions 7 Or the steam generator shel.l 3.
The helght o~ the columns ~3 are such that when the crane assembly 7~ is in its ~ully raised position, that is when the travell-lng block 76 and swivel hook 75 are 30 in their uppermost position, the personnel enclosures 40 will occupy their rest position ad~acent to lthe upper shoulder . ~
~25~8 47~763 34 of the upper section 7 of the generator shell 3, with the lowermost ends of the enclosures at a height in which they would be disposed slightly above any tube bundle 23 that might be in place within the generator. Thus the enclosures 40 may be employed by working personnel to assist in removal of securing paraphernalia, if desired. Otherwise, such tube bundle 23 will be absent, following its removal for replacement by a new tube bundle means (not shown) and the working personnel enclosures 40 may be lowered by opera-10 tion of the crane assembly 78 to a position within the lower -portion 5 of the generator shell 3, in which position they F ,9 v are shown in dot-dash outline in ~ *~e 2, for a working relationship with the top of the tube sheet 11, Fig. 1, and which may involve the removal of tube stubs (not shown) ~ -remaining from a previous tube bundle removal operation.
Tools (not shown) suspended from the hoists 73 may be manipu-lated by the working personnel standing within the enclosures 40 via the hand holes 48 beneath the windows 46 to assist in performance of the work tasks.
Following completion of all work tasks to be per-formed at the tube sheet site by use of the apparatus of the present invention, the enclosures 40 may be returned to their uppermost repose posItions in which they are shown in solid outline in Fig. 2 and the entire assembly may be removed from the upper rim 34 oP the upper shell section 7 by use oP a radius crane (not shown) permanently located within the con-tainment ~ss~ (not shown) at the reactor power site of the generator undergoing repair. Such raising of the gondola or enclosure assembly by the radius crane can be effectuated by use of such as a suitable cable sling and eye bolts (not 1~5~Z8 47,763 shown) affiliated for example, with the mounting frame mem-bers 82 atop the columns 83. The entire assembly will then be raised upwardly away from the mounting pads 86 disposed on the upper rim 34 of the upper shell section 7 and then dis-placed laterally and lowered onto e~tended sections ~not shown) of the columns 83 to maintain the shielded personnel enclosures 40 in suspension from the swivel hook 75.
' ~ '. , , ~ .
'' '-~ ,`
',;;; ' : , ' .
Figure 6 is an elevation Vi8W, partly in outline and partly in section showing a manually operable means for ef~ecting turning mo~ement o~ the shielded work statiGn apparatus of the present invention when disposed within the shell o~ the steam generator; and Figure 7 is an elevation view3 partly in outline~
showing the crane assembly and upper support frame of this in-ventlon.
Referring to Fig. 1 in the drawings the steam generator 1 with which the movable work station apparatus of the present invention is i~tended to be employed ~or replacement of the tube bundle 23 therein typically includes a vertically orie~ted shell ~, the shell oomprising a lower cylindrical portion ~ and an upper cylindrical portion 79 larger in diameter than the lower portion 5 and a frustoco~-~: ical transition portlon 9 ~oining the lower and upper portions 5 and 7. A tube sheet 11 is disposed in the lower end o~ the ~` lower portion 5 of the shell and has a plurality of holes for accommodating the ends of U-shaped tubes 13 which extend upwardly from the tube sheet 11 and are closely packed to form the tube bundle 23 disposed ~ertically wlthin the lower portion 5 of the shell 3.
A hemispherical channel head 15 is fastened to the tube sheet 11 and has a divider plate 17 disposed therein, A primary fluid inlet nozzle 19 supplies heated affluent pri-mary fluid from a nuclear reactor core (not show~) to one portion of the channel head 15 and a discharge ~ozzle 21 is disposed in the channel head 15 to return the afflue~t pri-30 mary ~luid to such reactor core.
~Z~ 47,763 A plurality of support plates 25 are disposedthroughout the tube bundle 23 to support the tubes 13 at various locations along their length to reduce flow-induced vibrations. Anti-vibration bars 27 are also disposed adjacent to the bends in the tubes 13 to prevent vibration in this portion of the tube bundle 23.
A wrapper or sleeve 29 is disposed between the tube bundle 23 and the shell 3 so as to form an annular space ~ ;
31 therebetweenO The upper part of the upper section 7 of the shell has been removed to gain access to the interior of the steam generator in preparation for removal and replace-ment of the tube bundle therein. Various components of the steam generator usually disposed in the upper section 7 of the shell 3 also have been removed from the steam generator as shown in Fig. l to provide access to the top of the sleeve encircling the tube bundle 23. The upper circular edge 3L~ of the upper portion 7 of the shell 3 will be smooth and even and rather precisely defined and will lie in a horizon-tal plane by virtue of a rather careful previous grinding, 20 cutting or machining operations previously referred to as preparatory to in situ tube bundle replacement.
~ 'ypical operation o~ the steam generator, which per ~e forms no part of the present invention, involves the ~low o~ heated primary fluid from a nuclear reactor core upwardly through the tube sheet 11 and one branch of the U-shaped tube bundle 23 and downwardly through the other branch of such tube bundle and back through the tube sheet 11 to the discharge nozzle 21, while secondary fluid above the tube sheet 11 and outside the tube bundle 23 becomes 30 heated for forming steam for conveyance by conduit means ~S~2~ 47,763 (not shown) to a turbine (not shown) operated by such steam.
Referring to ~g~. 2, 3, 4 and 5 in khe drawing, the present invention comprises an enclosure assembly including a pair of radiation-shielded worker enclosures 40 each of which is adapted to accommodate two workers (not shown) standing in upright attitudes. Each of the shielded enclo-sures 40 has wall portions made of relatively thick steel plate joined together as by weldments (not shown) and includes four separate sections, two upper sections 40Ul and 40U2 and 10 two lower sections 40Ll and 40L2 to facilitate set-up and knock-down of the enclosure when desired. The vertical walls of the enclosures 40 may be in the order of several inches thick, with a bottom wall of about four inches tllick, for example, and a top cover member 41 of something like a half inch thick or less, for example. Total height of each en-closure may be in the order of slightly less than eight feet, which affords ample height within the interior of the enclo-sure to accommodate the workers therein in their standing attitude, even while wearing hard hats as the case might be.
Each lower section 40Ll and 40L2 of the enclosures 40 is provided with a bottom-hinged sheet steel door 42 of flanged-edge construction suitably proportioned to permit the workers to enter and leave via entranceways in the forward walls of such enclosure sections in open, lowered, positlons of the doors as shown in the lower lefthand portion of fig.
5 affiliated with the enclosure section 40Ll. This is arrived at by providing hinges 43 at the lower horizontal edges of the doors 42 and provision of a manually operable latch 44 at the upper edge of the door for Securing same w~en closed.
Hinged retractable support arms 45 hold such worker entrance ~ 47,763 doors 42 in a horizontal attitude when opened. The front of each of the upper enclosure sections 40Ul and 40U2 is provided with a thick lead glass window 46 arranged to extend hori~ontally outward beyond the location of the forward vertical face of the lower housing section 40Ll, 40L2 and which has an inwardly e~tending lower portion con-structed and arranged to afford a downwardly-aimed view to working personnel withln such enclosure. Relatively thick .
lead glass windows 47 are provided also i.n the rear walls of upper enclosure sections 40Ul and 40U2 to afford additional observation locations to personnel within the enclosures 40.
Hand .holes 48 are provided in the upper housing or upper enclosure sections 40Ul and 40U2 beneath the observation windows 46 and 47 at front and rear to enable tools (not shown), for examplej located outside the enclosure to be manipulated by working personnel standing within such en-closures. The front of each enclosure 40 is wider than the rear and its side walls taper inwardly from front to rear to provide a configuration that nests conveniently ad~acent to the inner surface of the lower section 5 of the shell 3 of the steam generator l in absence of the tube bundle 23 being replaced.
The upper and lower sections of the shielded enclo-sures 40 are removable supported in support cage assemblies 50 made up of horizontal and verti.cal angle arm members welded together. Vertical guide rollers 51 are carried at the bottom of the support cage assemblies 50 at the rear of the working personnel enclosures 40 for vertical guiding ~operation with the inner wall of the lower ~ection 5 of the shell 3 of the steam generator l while such assembly is ~ ~2 ~ 47,763 being transported vertically through the interior of such shell section as during transport within the generator shell to and from a work site. The working enclosures 40 are so proportioned that when they are disposed within the interior of the low~er section 5 of the steam generator shell 3 as shown in ~g. 4, for example, they provide a vertical clear-q~ ~
anceway ~ therebetween~ such clearanceway affording a pathway for disposition, travel, and manipulation of tools (not shown) and/or workpiece parts (not shown) being manipulated or worked on. The support cage assemblies 50 for the two shieldedpersonnel enclosures 40 are mechanically connected through the medium of a supporting structure to be described subse~
quently.
The bottom portions of such support cage assemblies include a plurality of rubber tired wheels 52 constructed and arranged for circumferential rolling engagement with the inner surface of the lower shell section 5 of the steam generator 1 relative to turning mo~ement about the central axis ~ of such shell section. One of such wheels 52 affiliated with each enclosure 40 assembly is actuable by a pneumatic cylinder means (not shown) to a retracted position disposed out of engagement with the inner shell wall to prevent interference with vertical movement when desired. In addition, one of the wheels 52, in accord with the showing in figs. 4 and 6 is turnable manually b~ a hand wheel 54 from the interior of one of the enclosures 40 to effect turning movement of the interconnected enclosure 40 when desired. The operating mechanism for effecting such a turning movement of the one rubber tired wheel 52 is affiliated with a support frame 50 for the one enclosure 40 and includes for example a rotary ': .
5 ~
~7~763 shaft ~5 secured to the wheel 52 to turn therewith, a number o~ brackets 56 for 9upport of the wheel and for guiding turning movement of khe drive shaft 550 A right-angle gear dri~e mechanism 57 has a drive input ~haft 5g connected to the hand wheel 5~ and an output shaft 59 joined by a sui~able coupling 60 to the u~per end of the dri~e ~haft 55. The shaft 5~ connected to the hand wheel 54 will pass through a side wall of the respective en-closure ~0~
An air conditioning unit 90 with intake fil~er 9~ is pro~ided each one of the personnel enclosures ~0 mounted on ~he top cover member ~1 thereof ~or comfork and sa~ety of ~he personnel therein~
Each of the personnel enclosures ~0 is ~oined to an o~erhead horizontal suppor~ frame assembly 65 through the medium of respecti~e vertical interconnecting frame means 66. iThe horizontal support frame assembly 65 includes a pair o~ I-beam members 67 extending above the enclosures 40 across the clearanceway 92 kherebetweens Opposite ends o~ the I-beam members 67 are removably attached to the tops of the interconnect frame means 66 by means of plates 6~ and bolts 69. A pair of cross carriage tracks 70 o.f I~beam construct,ion are welded to the underside o~ the I-beam members 67 and extend widthwise of the enclo~ures 40 at opposite sides of the upper end of the clearanceway 924 A plurality of cross carriages 71, four being shown in Figo 3 for ex.~mple? are arranged for movement widthw~se of the enclosures ~0 along the tracks 70 through the medium of rollers 72 suppo~ted by brackets welded to the upper edge of the cross-carriage beams 71 at theîr opposite ends. Each of ~he cross-carriages 71 carries a power operated hoist 73 suspended from a re~
spective ~rolley ~;Z592~
74 roller-suppor~ed on ~he lower flange of the cross carriage beam 71; one such hoist 73 being shown in Fig. 2 and one such hoist being shown in Fig~ 3.
The entire assembly i~cluding the personnel en~
closure~ 40, support cages 50 g ~ertical in~erconnect ~rames 66, and horizon~al support frame 659 includ1ng the cross carriage tracks 71, hoist 73, etc~ is supported for vertical and rotary mo~ement about the central axis of the steam generator shell 3 on a swi~el hook 75 at the lower end o~ a travelling block 76. The block 76 i~ suppor~ed by multiple cable loops 77a from a sheave 77 formlng part of a crane assembly 7~ that includes a cable drum 79 and members ~1 forming a rectangular frame supporting such shea~e 77, motor ~0, and cable drum 79 for proper payout and reel-in of the cable to and from the shea~e 77 for rai~ing and lowering the travelling block 76 and the load supported thereby on the swirel hook 75 as shown in Figures 5 and 7. The crane assembly 7~ in ~urn is ~upported on a rectangular frame made up of horizontal I-beam members ~2 welded together at their corner~ a~d support,ed at such corners by vertical I beam columns ~3 secured to and ex-tending upwardly from a support ring ~5 which in turn finds support from mounting bracke~ assemblies ~6 dispo~sd immediately beneath the columns ~3 and carried on the upper rim edge 34 of the upper portions 7 Or the steam generator shel.l 3.
The helght o~ the columns ~3 are such that when the crane assembly 7~ is in its ~ully raised position, that is when the travell-lng block 76 and swivel hook 75 are 30 in their uppermost position, the personnel enclosures 40 will occupy their rest position ad~acent to lthe upper shoulder . ~
~25~8 47~763 34 of the upper section 7 of the generator shell 3, with the lowermost ends of the enclosures at a height in which they would be disposed slightly above any tube bundle 23 that might be in place within the generator. Thus the enclosures 40 may be employed by working personnel to assist in removal of securing paraphernalia, if desired. Otherwise, such tube bundle 23 will be absent, following its removal for replacement by a new tube bundle means (not shown) and the working personnel enclosures 40 may be lowered by opera-10 tion of the crane assembly 78 to a position within the lower -portion 5 of the generator shell 3, in which position they F ,9 v are shown in dot-dash outline in ~ *~e 2, for a working relationship with the top of the tube sheet 11, Fig. 1, and which may involve the removal of tube stubs (not shown) ~ -remaining from a previous tube bundle removal operation.
Tools (not shown) suspended from the hoists 73 may be manipu-lated by the working personnel standing within the enclosures 40 via the hand holes 48 beneath the windows 46 to assist in performance of the work tasks.
Following completion of all work tasks to be per-formed at the tube sheet site by use of the apparatus of the present invention, the enclosures 40 may be returned to their uppermost repose posItions in which they are shown in solid outline in Fig. 2 and the entire assembly may be removed from the upper rim 34 oP the upper shell section 7 by use oP a radius crane (not shown) permanently located within the con-tainment ~ss~ (not shown) at the reactor power site of the generator undergoing repair. Such raising of the gondola or enclosure assembly by the radius crane can be effectuated by use of such as a suitable cable sling and eye bolts (not 1~5~Z8 47,763 shown) affiliated for example, with the mounting frame mem-bers 82 atop the columns 83. The entire assembly will then be raised upwardly away from the mounting pads 86 disposed on the upper rim 34 of the upper shell section 7 and then dis-placed laterally and lowered onto e~tended sections ~not shown) of the columns 83 to maintain the shielded personnel enclosures 40 in suspension from the swivel hook 75.
' ~ '. , , ~ .
'' '-~ ,`
',;;; ' : , ' .
Claims (6)
1. Work station apparatus for use in an opened-top steam generator shell of a nuclear power plant, radiation shielded enclosure means for working personnel, having radiation-protective glass windows and holes for observation and manipulation of tools, swivel means suspending said enclosure means with freedom for turning movement about a vertical axis, crane means for disposition atop said opened-top shell to raise and lower the aforesaid enclosure-means-supporting swivel means, and turning means operable from said enclosure means when suspended within said shell, to effect the aforesaid turning movement.
2. Work station apparatus as set forth in claim 1, wherein said radiation shielded enclosure means comprises a pair of enclosures disposed at opposite sides of a vertical clearanceway, aforesaid windows and holes face into said clearanceway, and said apparatus further comprises tool hoist means carried by said swivel means, for raising and lowering tools vertically through said clearanceway.
3. Work station apparatus as set forth in claim 2, wherein each of said enclosures is constructed and arranged to accommodate two working persons while standing upright.
4. Work station apparatus as set forth in claim 2, 47,763 wherein each of said enclosures has an entrance door means openable to a horizontal attitude in said clearanceway.
5. Work station apparatus as set forth in claim 1, wherein said enclosure means is suspended by said swivel means via horizontal frame means from which the afore-said pair of enclosures depend and with which the aforesaid tool hoist means is affiliated.
6. Work station apparatus as set forth in claim 1, further comprising pedestal means for supporting said crane means and for support by and extension above the top edge of an opened-top steam generator shell.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA338,818A CA1125928A (en) | 1979-10-31 | 1979-10-31 | Radiation shielded movable work station apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA338,818A CA1125928A (en) | 1979-10-31 | 1979-10-31 | Radiation shielded movable work station apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1125928A true CA1125928A (en) | 1982-06-15 |
Family
ID=4115484
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA338,818A Expired CA1125928A (en) | 1979-10-31 | 1979-10-31 | Radiation shielded movable work station apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1125928A (en) |
-
1979
- 1979-10-31 CA CA338,818A patent/CA1125928A/en not_active Expired
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