Inspection device

A device for inspecting the interior of steam generators capable of visually inspecting interior of tubes in steam generators, including upper portions steam generator tubes, tops and bottoms of support plates, wrapper-to-support plate welds, and other internal structures.

FIELD OF THE INVENTION 
The present invention relates to the field of inspection devices generally, 
and more specifically to nuclear power plant steam generator inspection 
devices. 
BACKGROUND OF THE INVENTION 
In a nuclear reactor power plant, a nuclear reactor vessel is used to 
generate heat for the production of steam and electricity. The reactor 
vessel is typically a pressurized vessel enclosing a core of nuclear fuel 
and cooling water. Such nuclear power plants typically contain three major 
components: a 1) reactor which produces superheated water which is 
transported to one or more 2) steam generators, and a 3) power turbine, 
driven by steam which generates electric power. 
The superheated water is transported to the steam generator by pipes. These 
pipes feed the water into numerous tubes within the steam generator. These 
tubes are U-shaped, feeding the water back to the pipes at the outlet of 
the steam generator to be recirculated back to the reactor. The tubes in a 
nuclear steam generator typically form an inverted "U" separated by a 
lane, and held together by a plurality of support plates, separated at 
periodic vertical intervals. The height of each tube row may exceed 
thirty-two feet. Six to eight or more support plates are used, each 
separated vertically at three to six foot intervals. In the steam 
generator, the tube carrying the superheated water are quenched with cool 
water, which generates the steam which drives the turbine to produce 
electricity. 
This procedure for generating steam presents several problems. The water 
used to quench the tubes often has impurities and chemicals which may 
corrode both the steam generator tubes and the support plates and lead to 
other damage. Even though periodic inspections of nuclear steam generators 
are required for compliance with safety regulations, monitoring steam 
generator cleanliness remains a problem. The highly corrosive environment 
of the steam generator is particularly problematic for many of the older 
nuclear reactors in service throughout the world. 
In the past, steam generator tubes and support plates were inaccessible for 
visual inspection. Information was gathered by complicated systems which 
could not adequately inspect all sections of tubes and support plates. 
Because of the highly radioactive environment and the heat of the pipes, 
direct visual human inspection has typically been restricted to between 
three and five minutes per man per six month period. This time period does 
not provide ample opportunity for the careful inspection for corrosion, 
holes and leaks. It is therefore difficult to inspect within the narrow 
lanes and tube separation gaps at the support plates, because of the heat, 
radioactivity and narrowness of the lanes separating the tubes. 
Commonly assigned U.S. Pat. No. 5,265,129, the entire contents of which are 
incorporated by reference herein as though made part of the present 
specification, discloses an improved apparatus and method for inspecting 
steam generators, especially inspecting within the lanes located between 
the tubes. However, even this improvement does not afford an operator an 
unrestricted view of the entire contents of the steam generator. 
Tubes typically extend through support plates at quatrefoil holes. These 
openings provide flow through features to improve water flow in the 
generator and to reduce the build-up of sediment at the support plates. 
Nevertheless, the small areas where the quatrefoil opening must contact 
the tube results in areas of material build-up on the tubes, or even 
adherence of material being "plated out" on the tubes. This material will 
contribute to premature corrosion of the tubes. With known inspection 
devices, this condition will go undetected on all but the tubes bordering 
the lane. 
Further, the orientation of component parts within steam generators 
provides extreme challenges to designing workable devices for inspecting 
such areas. Insertion holes (also known as hand holes) at the bottom of 
the steam generators are often as small as a five or six inch diameter. 
For the purpose of this application such portals will be referred to 
inclusively as access ports. Flow distribution baffles within the 
generator often obstruct any room to maneuver equipment within the 
generator. Inspection within steam generators at elevations as high as 
thirty feet or more provide significant engineering challenges. In 
addition, the flow slots between tube rows are often less than two inches 
wide and tube separation gap dimensions are often less than one inch (down 
to about 0.30 inches). A device which could enable the visual inspection 
of many areas within the steam generator, including between tubes, over 
and under all support plates between the top of the support plate above 
the hand hole and the bottom of the top most support plate, etc. would be 
highly useful. 
SUMMARY OF THE INVENTION 
The present invention is directed to an inspection device that is capable 
of visually inspecting tube regions in steam generators, including upper 
portions of steam generator tubes, tops and bottoms of support plates, 
wrapper-to-support plate welds, and other internal structures. 
Further, the present invention is directed to a device for inspecting areas 
of the steam generator and identifying areas for targeted cleaning, by use 
of a fully automated computer assisted and remotely controlled inspection 
robot. 
Still further, the present invention is directed to a device for inspecting 
the interior of a steam generator comprising a first boom, a second boom 
having a first end pivotally attached to the first boom and a second end, 
a head assembly attached to the second end, a plurality of registration 
guides attached to the head assembly and having a means for moving the 
guides from a first retracted position to a second extended position and a 
movable sensing wand attached to a drive mechanism in the head assembly at 
a proximal end and having a sensor at a distal end. 
In one preferred embodiment, the first boom is a rail assembly, the second 
boom is a telescoping boom, the sensing wand is a telescoping wand, and 
the sensor is a camera. 
In addition, the present invention provides a method for inspecting the 
interior of a steam generator comprising providing an inspection device 
comprising a first boom, a second boom having a first end pivotally 
attached to the first boom and a second end, a head assembly attached to 
the second end, a plurality of registration guides attached to the head 
assembly, and a movable sensing wand attached to a drive mechanism in the 
head assembly at a proximal end and having a sensor at a distal end. The 
inspection device is inserted through an access port in the generator. The 
first boom is then positioned in the tube lane between and perpendicular 
to the center most tube rows. The second boom then is uprighted within the 
generator to a vertical position generally parallel to the tubes. The 
device is then located at a predetermined location. The registration 
guides are actuated to be extended against opposing tubes across the tube 
lane. The wand is then actuated to position the sensor at a desired 
location. The sensor then records and displays visual images at a display 
located remotely from the device.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention positions an inspection head into a flanged access 
port having a diameter of about six inches near the bottom of a steam 
generator. The device is mounted on a specially designed rail-like adapter 
to facilitate entry through a small opening. The device, designed for a 
vertical lift of about 30 feet or more, first extends horizontally into 
the steam generator through the flanged access port. The device rests near 
the base of the steam generator in the region known as the tube lane. The 
tube lane is the narrow area created by the innermost inverted U-tubes. 
Steam enters one side of the U-bend (the hot pipe). and travels around the 
U-bend of the pipe and is quenched by the cool water in the steam 
generator and proceeds around to the other side of the U-bend (the cool 
pipe). Once the tool is installed horizontally, it is raised to a vertical 
position through a flow slot in the support plates in the generator. The 
rail assembly is moved in or out as the tool is raised to keep the head 
aligned with the flow slot in each support plate. Support plates occur 
vertically throughout the height of the generator at three to six foot 
intervals. The device is then maneuvered into a vertical position through 
use manual cranking. 
The hydraulically-controlled telescoping assembly is then activated 
allowing the device to extend vertically to the desired height which may 
cause the device to proceed through the flow slots of successive support 
plates. Computer-controlled or manually controlled machinery extends the 
telescoping section to the height to be sensitively and accurately 
measured to assure an operator of the precise vertical location of the 
device head within the steam generator. 
Once the device is in the vertical position, the horizontal position 
location is verified visually and numerically by determining at which tube 
column the device is located. This is accomplished by mechanical 
distancing apparatuses, such as pulleys or gears, or may be done by using 
position sensors such as, for example, pattern recognition sensors, etc. A 
registration apparatus is then preferably pneumatically powered to extend 
sets of registration guides (which are finger-like projections) from a 
retracted position at rest. When each guide set is extended, one guide 
will contact the hot tube and one guide will contact the cool tube of the 
same U-tube. 
The probe camera at the end of an inspection wand is then raised, 
preferably by remote computer control of a direct motor drive, into the 
desired inspection position between specified tube columns. As the device 
is telescopically raised or lowered vertically, an upward facing head 
camera mounted in the top of the inspection head gives a view of the first 
tube row and the flowslot or lane. Preferably, the head of the device 
located atop the vertically telescoping section contains an additional 
camera or sensor facing the center of the generator to provide additional 
information on device location and generator condition. The device is 
therefore able to inspect both the top and bottom of tube support plates 
as well as the wrapper welds at the support plates, and other internal 
structures 
FIGS. 1-7 show one preferred embodiment of the present invention. 
Inspection device 1 comprises a telescoping boom assembly 12 with head 
assembly 18 attached. One (proximal) end of sensing wand 16 attaches to 
head assembly 18. The other (distal) end of the wand houses probe 20 which 
houses a camera and light assembly See FIGS. 17 and 18. First boom rail 
assembly 2 attaches to telescoping boom 12 at uprighting pivot clamp 3. 
The generator wall 4 has access port 5 to which access port mounting plate 
6 attaches. Rack drive servo motor 7 attaches to mounting plate 6. Manual 
crank handle 31 drives gear 8 which is attached to rod 9. Rod 9 attaches 
to clamp 9a which is secured about telescoping boom 12. Manual crank 
handle 31 can be operated to deploy the second telescoping boom 12 and to 
retract telescoping boom 12 to the retracted position. Cable housing 14 
attaches to head 18. Quick release feature 21 (FIG. 5) removably secures 
assembly 12 to head assembly 18. Registration guides 22, 24, 26, 28 are 
shown. See FIGS. 5-7. One end of registration links 30 attach to guides. 
The other end of the links 30 attach to the air cylinder attachment block 
62 of air cylinder base 60. See FIG. 9. 
FIG. 3 shows the wand 16 in a deployed position. FIG. 4 shows wand 16 in a 
starting/retracted position. FIGS. 5-7 show an additional camera 40 in 
housing 42 at the proximal end of wand 16. Further top head camera 50 and 
side head camera 52 are positioned at the top housing 54 of head assembly 
18. Air cylinder 44 provides pneumatic pressure to the registration 
guides. FIG. 8 shows a top view of one preferred embodiment of the present 
invention. Camera 40 positioned at the proximal end of wand 16 is shown 
along with side head camera 52, top head camera 50. Registration guides 26 
and 28 are shown in their retracted position while guides 22 and 24 are 
shown extended. 
FIG. 9 shows an exploded view of the registration assembly. Air cylinder 
base 60 has driver block 62 fit over top post 64. Registration links 30 
have through holes 66, through which link pins 68 extend and secure in 
driver block 62. Retainer caps 70 affix to link pins 68. Link pins 72 pass 
through links 30 and secure in guide openings 74. Link pins 76 pass 
through links 30 at openings 66 and secure in openings 78 in base 60. 
Elbow fitting 80 houses barb fitting 82 and is housed in pneumatic air 
cylinder 84. Fitting pins 86 fit into air cylinder. 
FIG. 10 shows an enlarged view of the wand 16. The wand 16 has an inner 
channel 90 and a support tube 92 both of which engage pivot arm fixture 
94. Bearing gear 96 fits into bearing 98 which rests against pulley 100. 
Pivot arm 94 houses cable guide 102. Coupling 104 secures channel 90 and 
support tube 92. Probe head 106 houses camera and light assembly (not 
shown) and secures to inner channel 90 and support tube 92. 
FIG. 11 shows a cross-sectional top view of a longitudinal half of a steam 
generator bisected at the flow slot. Support plate 39 is shown with 
hundreds of tubes 79 and multiple flowslots 13 passing therethough. 
FIG. 12 shows the present invention deployed through access port 5 of 
generator wall 4. FIG. 12 depicts the present invention in both the 
horizontal retracted mode (position A) in which it passes through the 
access port, and the deployed vertical mode (position B). It is understood 
that for illustrative purposes, the generator is viewed across a 
longitudinally bisected line in the plane of the device (as shown in FIG. 
11) to give a better view of the present invention. 
FIG. 13a shows the present invention deployed in the tube lane 81. The 
device is deployed vertically in the lane through the flowslot 83 in 
support plate 85. Wand 16 is in the retracted position. FIG. 13b shows 
wand 16 activated to inspect down the tube column into areas which could 
not be inspected using past methods and apparatuses. Cables 87 are 
visible, as are tubes 79, and support plates 85 and 89. 
FIG. 14 is a schematic partially exposed view of cable housing 14. Pulley 
100 supports cable 220 which wraps about weighted pulley 222. Constant 
force spring 230 provides balance force to weighted pulley 222. 
FIG. 15 is a schematic block diagram of the preferred control layout of the 
present invention. Area monitor 300, control interface computer 302, 
optional auxiliary electronics 304, and hydraulic pump 306 are preferably 
positioned outside of a bioshield 308 and have their cables 310 directed 
to control electronics 312 and power and air supplies 314 which are set up 
adjacent the generator access opening 321. A rack and pinion drive 316 is 
attached to rail assembly 319 which is attached to pivot clamp 320 on 
device 10. Rail assembly 319 supports the device 10 as it is slid into 
position in the generator. 
FIG. 16 is a schematic representation of the preferred computer interface 
and circuitry provided to operate remotely the preferred inspection device 
of the present invention. 
FIG. 17 shows a cross-sectional enlarged view of the probe 20 of the wand 
assembly 16. Camera 400 is shown along with lamp 402, 404 and lamp lenses 
406 and 408. FIG. 18 shows an end view 106 of the probe 20. 
In operation, the uprighting equipment comprises two major subsystems; the 
access port mounting equipment and the rail assembly. The access port 
mounting equipment comprises a backing plate 6, two cam roller support 
plates and a rack drive servo motor assembly 7. The backing plate 6 
completely covers the face of the access port 5 and has slotted mounting 
holes to allow alignment with the tube lane, and has a relief cut in the 
backside in the area of the sealing surface of the access port to prevent 
damage to this surface. Preferably, six 1" diameter cam rollers are 
mounted on each of two cam roller support plates. These rollers support 
the first boom rail assembly 2 on all four horizontal edges. The rack 
drive servo motor 7 is controlled by the operator to precisely position 
the rail 2 within the steam generator. The rack drive servo motor housing 
2 is mounted to one of the roller support plates by a pivot and preferably 
is held in place by a single locking, quick release pin. The rail can be 
installed and repositioned by hand by removing the locking pin and 
swinging the motor assembly up. 
The rail assembly 2 comprises two parallel, stainless steel bars, spaced by 
stainless steel blocks on both ends. For portability and ease of 
installation the assembly preferably comprises three sections. The primary 
purpose of the rail is to support and position the telescoping segment's 
uprighting mechanism, preferably a pivot clamp. Also the rail provides a 
means of tensioning the uprighting rod using a screw mechanism in the 
middle section. To move the rack assembly horizontally, a rack is embedded 
into the top of one of the two parallel stainless steel bars. This rack 
mates with the pinion on the end of the rack drive servo motor. The three 
rail assembly sections are joined by guide pins, preferably 1 inch (2.54 
cm) in diameter, and preferably are locked together with the thumbscrews. 
In an alternative embodiment, air fittings for powering the telescoping 
segment locking pin release cylinder may be embedded into the ends of the 
sections and must be depressurized before a section can be removed from 
its mating section. The shaft sections link a removable handle at the end 
of the rail to the screw used for uprighting the segment. 
In one preferred embodiment, the inspection wand is made from thin section 
telescoping tubing actuated by a stainless steel 4-40 threaded rod driven 
by a servo motor. The probe head 20 itself, as shown in FIG. 17, 
preferably is made from an inert polymeric resin material, most preferably 
Delrin.RTM. or Teflon.RTM., and houses the inspection lighting 402 and 404 
and camera, which is preferably a CCD camera 400. The inspection probe 
lighting intensity is set from the remote operator station or from the 
main control console as would be understood in the field of remote 
inspection devices. 
The wand 16 preferably pivots at the distal end of the telescoping segment, 
or shoulder joint. A set of bevel gears actuated by a servo motor powers 
the joint. The design of this pivot is such that when the device is 
de-energized, the motor can be freely back-driven. This safety measure 
helps to ensure that in the event of a tool failure, the probe can be 
removed without damaging the steam generator components. In one preferred 
embodiment, the wand further consists of a double-barrel outside tubular 
assembly with a double-barrel inside the tubular assembly and an internal 
screw. The inside assembly can be made to extend from and retract into the 
outside tubular assembly, making the total wand length shorter or longer 
as needed for inspection purposes and to negotiate the support plates 
during deployment into the tube columns. The distal end 19 of the inside 
tubular assembly attaches to the camera and light assembly probe 20, as 
shown in FIG. 19. The proximal end of the outside tubular assembly 
contains the screw (threaded rod), the drive motor, wand camera 40, and 
attachment shaft for attaching the wand to the head assembly. The 
attachment shaft rotates to position the wand at the desired angle in the 
steam generator tube column. 
In one preferred embodiment, the registration mechanism may be actuated to 
move in laterally forward or backward one tube at a time by extending one 
set of registration guides to an adjacent tube space, releasing the other 
set of registration guides, and moving the device to align between a new 
tube column. The registration guides 22, 24, 26, 28 prevent unwanted 
motion of the head while the inspection wand 16 is positioned between tube 
columns. The guides 22, 24, 26, 28 align vertically with the steam 
generator tubes. The guides 22, 24, 26, 28 are actuated by pneumatic air 
cylinders 29 and fail in the closed position when the device is 
deenergized. The guides 22, 24, 26, 28 are preferably coated with a 
material to eliminate the risk of damaging the tubes upon contact. 
Preferably, the registration guides 22, 24, 26, 28 comprise Delrin.RTM. 
and Teflon.RTM. or other highly resilient and adherent protective 
materials. 
An additional air cylinder arranged horizontally moves one registration 
guide with respect to the other to index the head to a particular column. 
By cycling the registration and indexing cylinders, the head can be 
effectively "walked" from one tube column to the next. When a series of 
several "walking" cycles are combined, the device can move across an 
entire flowslot width. For example, with reference to FIG. 7, guides 22 
and 24 are extended and would contact the hot and cool tubes of a single 
U-bend tube in a generator. Air cylinder 29 would be activated to move the 
head 18 a distance sufficient to align guides 26 and 28 with the next 
tube. Guides 26 and 28 would be pneumatically extended while guides 22 and 
24 would be retracted. Air cylinder 29 is again activated to push head 18 
"ahead" until guides 22 and 24 are adjacent the next tube, and so forth. 
As the head is pushed or pulled in a direction along the tube row, an 
integrated tilt sensor senses that the second telescoping boom is out of 
verticality. The sensor sends a signal to the servo drive attached to the 
first boom rail assembly and advances or retracts a distance sufficient to 
reestablish second boom verticality. To assist in maintaining proper 
vertical positioning, a dual axis tilt sensor in the base of the 
telescoping segment provides operator feedback for +/-20 degrees of 
vertical tilt. 
Since the inspection probe is telescopic, a substantial length of cable 
must be managed and stored within the inspection head. A constant force 
spring 230 and a set of pulleys 100, 222, as shown in FIG. 14, rising in 
an enclosed track prevents the inspection camera cabling 220 from becoming 
tangled and potentially jammed while in operation. This guide also serves 
to protect the angle joint servo motor and provides a sturdy point to 
strain relieve the umbilical cable. 
The inspection head is linked to the main control console through a 
multi-function umbilical cable 87 (shown in FIG. 12). This umbilical cable 
87 carries all electrical power, control and video signals. It 
additionally contains four small air lines for the pneumatic components. 
The primary electrical cable is internally reinforced with Kevlar filler 
strands for strength; the cable also serving as the emergency retrieval 
cable. 
The additional cameras 50, 52 used are preferably positioned on the head to 
look up and forward on the probe side. These cameras 50, 52 are used when 
installing and uprighting the system. These cameras 50, 52 also provide 
the operator views when traversing flowslots 13 of the support. The 
lighting and camera operation is preferably controlled by an operator at 
the computer interface. 
In one preferred embodiment, a plurality of proximity sensors, preferably 
eight, alert the operator to unexpected or undesirable operating 
conditions and also enable the computer to assume automatic control over 
the device. 
Further, in one preferred embodiment several tapered bumpers, preferably 
made from or coated with Delrin.RTM. help guide the head through the 
flowslot and ensure that the proximity sensors will be within an 
acceptable distance from the edge of the flowslot and to sense arrival at 
the preselected position. Other bumpers also serve to absorb potential 
impacts with support plates while traversing up through the steam 
generator. 
Due to the sensitive nature of the generators being inspected, the 
inspection device is preferably made from strong, non-reactive materials. 
Materials which include chlorides, fluorides and other halogens are 
inappropriate materials. 
The telescoping segment 12 of the present invention is more fully disclosed 
in commonly assigned U.S. Pat. No. 5,265,129 which is incorporated by 
reference herein. The segment 12 is a single acting, multi-sectioned 
telescopic cylinder, designed to deliver inspection head 20 and wand 16 
through the flowslot openings in the generator. The segment 12 preferably 
uses hydraulic pressure as the motive force. The tubes preferably are made 
from stainless steel. Bronze bushings and aluminum pistons create the 
bearing surfaces for side loads with two cup seals present on each piston 
to limit fluid loss. Demineralized water is the preferred fluid, with the 
preferred maximum operating pressure being approximately 120 psi. The 
extended height of the tool may be measured by known gauges, but is 
preferably measured by a string wound take-up spool within the base of the 
telescoping segment. String tension is maintained by means of the torque 
supplied by an electric motor linked to the take-up spool via a set of 
spur gears. A magnetic rotary encoder 259 spinning on an axis common to 
the motor shaft provides quadrature output, which provides the feedback to 
a digital servo loop. The motor drive circuitry resides within the drive 
electronics 252 to limit motor current, thus preventing overheating and 
potential failure as would be understood by one skilled in the field. 
The distance the device moves, tube 79 column to tube column 79, down the 
tube lane within the generator is carefully calibrated such that, as the 
head of the device with the finger-like projections engages the tubes, the 
precise location of the device and the exact tube column being inspected 
is known with certainty. The inspection device, therefore may be made to 
move across the tube lanes 81 tube by tube if desired. The mechanism is 
preferably driven and computer controlled, and designed to step one tube 
at a time on command if desired, and send and receive positioning 
information allowing an operator to precisely and reliably know the 
precise area of the generator being inspected. The specially designed 
registration fingers or guides are made from materials which will not 
damage the tubes or any of the internal parts of the steam generator, but 
will also be durable enough to survive the harsh conditions. Preferable 
bumper materials include Teflon.RTM., and Delrin.RTM.. The guides are kept 
in place using either diverted pressure or spring tension from springs in 
the event air pressure is lost. A plurality of guides may be used, with 
two sets of positioning guides used on each side of the device head being 
particularly preferred. As mentioned above, the mounting rail can be made 
to automatically position the base of the device to maintain its vertical 
position to the next tube row. 
When the vertical telescoping assembly is mechanically raised to the 
predetermined desired location, an inspection wand 16 or arm is swung away 
from the body of the vertical structure perpendicular to the first boom 12 
and rail assembly and at a progressive angle until the arm is positioned 
at a desired location between the desired tube columns, and at a desired 
specified height between said tube columns, as shown in FIG. 3. 
Preferably, the camera head comprises at least one radiation tolerant 
charge coupled device (CCD) color video camera. The camera preferably is 
fixed focus and is remotely computer controlled with the necessary 
circuitry and supporting wires and cables to receive positioning 
instructions, and to send back to the control station, and other various 
displays, transmissions from the camera in the form of pictures and 
location information, as would be readily understood by one skilled in the 
field of microcameras, robotics and circuitry. Therefore the system is 
controlled remotely by the computer once it is installed. The control 
station has the capability to record the output of the cameras on a VCR or 
other monitor. The device functions may be controlled by commands which 
may be given on even a lap top-type computer as would be readily 
understood by one skilled in the field. The operator interface provides 
information to the operator such as wand position, device height, 
registration position, tilt angle, tube row and column being viewed, as 
well as a number of other functions as may be desired. 
As mentioned above, the wand additionally is able to extend to a 
predetermined position on command by extending the wand length 276 in yet 
another telescoping fashion via a telescoping mechanism. In this way, the 
wand 17 and probe head 20 can move into any desired position in the steam 
generator (e.g. into the tube lanes, into the tube bundles between tube 
columns, beneath and above support plates, etc.) by combining the 
movements of the vertical telescoping boom 12 and the telescoping 
movements of the wand 17. The upper wand camera 40, near the wand pivot 
point, further allows the operator to view down the length of the wand as 
it is deployed. This feature allows the operator a view of the operation 
of the wand 16, as well as a view of the condition of the generator 
interior. 
Therefore the device of the present invention can deliver status updates of 
the generator inspection to an operator in numerical and graphical form if 
desired; specifically relaying precise probe location (probe is the 
housing containing the camera and lights at the distal end of the wand) 
such as support plate level, tube row, tube column, joint value, etc. In 
addition tilt sensor readings, proximity sensor readings, air and 
hydraulic pressure readings and registration guide condition can all be 
delivered to the operator and optionally recorded via the attached 
supporting computer 240. 
Once installed, all mechanical operations of the device of the present 
invention may be manually or automatically power driven through electric 
and pneumatic controls with the video inspection accomplished using high 
resolution miniature cameras with complementary lighting devices. In 
operation, system commands are relayed by the operator via the computer to 
give absolute, relative and jog commands for individual points. Further, 
automatic commands may be computer programmed to carry out a specific 
inspection sequence, giving automatic sequences to position the probe. As 
mentioned above, additional cameras 50, 52 can be positioned about the 
inspection device, some cameras carrying the wand and probe head in the 
field of view, to have a view of the device itself within the generator. 
Programs can be provided to the computer to allow for sophisticated camera 
switching at any desired time to deliver images to selected monitors as 
desired. It is understood that useful computer programs can be written and 
implemented to control the present device and to prevent the operator from 
inadvertently entering any commands which could damage the probe or the 
entire inspection device. Of course such safety measures could be written 
to be overridden in an emergency. 
Preferably, the control hardware for the present invention can be divided 
into primary control hardware and operator station hardware. The primary 
control hardware is set up at the steam generator platform and comprises 
two small suitcase-sized cases 312, 314 in FIG. 15. One case contains the 
main control console 312 and the second case 314 contains bulk power 
supplies. Plant supplied AC power and compressed air are required to be 
supplied to these cases for system operation. 
A switching-type power supply provides power to sensitive computer hardware 
from the main control console case. The main control console 302 provides 
the system manual control capability. Power for motor loads, lighting, 
cameras and support circuitry is supplied by the bulk power supply case 
314. All system component connections terminate at the main control 
console 302. 
The operator station for the device preferably contains a control computer 
302, running a Microsoft Windows based graphical user interface, 
associated control hardware 304, video monitoring 300 and recording 
equipment and audio communication equipment. In one preferred embodiment, 
audio communications link the steam generator platform and the operator 
station to assist in setup and installation. The control computer 
preferably is a PC/104, standard 80486, 25 MHz, PC compatible 
microprocessor. In one preferred embodiment, distributed off the common 
PC/104 bus are three additional devices; 1) a Win Systems 48 channel 
digital I/O 280, 2) a Win Systems analog I/O 250 providing eight 12 bit 
analog inputs and two 12 bit outputs and 3) a Motion Engineering 32 bit 4 
axis motion controller 260. Three custom designed printed circuit boards 
interface each of these devices with associated components. The remaining 
applications to run the present system would be readily understood by one 
skilled in the field of remote inspection equipment. See FIG. 16 for the 
computer block diagram outlining one particularly preferred design. 
FIG. 16 shows a computer interface for remote operation. A sensor reading 
and lamp powering device 250 provides power to a probe lamp 256 through an 
amplifier 253 in the support electronics 252. The output of sensors, such 
as tilt sensors 257 and pressure sensors 258, are buffered by buffers 254 
and read by the sensor reading and lamp powering device 250. The support 
electronics 252 also contain a motor driver 255 to run the encoder motor 
259. The encoder's input 270 passes through amplifier 264 and buffer 263 
from the motion controller 260. Feedback is provided by the encoder 270 to 
the motion controller 260. The motion controller 260 receives feedback 
from the rack drive 272, the wand angle 274, and the wand length 276 and 
provides control signals through corresponding amplifiers 265, 266, and 
267. A digital I/O controller 280 through optical isolators and relay 
electronics 282 in the I/O support electronics 282 provide control signals 
to the registration guides 286, the lighting 288, the pumps 290, and the 
cameras 292 and receives control inputs 294. Interconnecting cable 242 
connects the computer 240 with the analog sensor reading/lamp power/motor 
driver device 250, the motion controller 260, and the digital I/O 
controller 280. 
The working mechanism for the wand 16 of the present invention may be 
powered, hydraulically , pneumatically, etc., with a pneumatically 
controlled design being particularly preferred. 
The preferred hydraulic pump assembly 306 for the telescoping (second) boom 
of the present invention comprises a centrifugal vane pump, pressure 
relief valve, two proportional control valves, a solenoid block valve, a 
fluid reservoir and pressure gauges. Control power and signals are fed 
from the main control console 302 over a single cable and main 110V AC 
power to operate the pump 306 is obtained from a source local to the pump. 
As mentioned earlier, retrieval of the extended inspection device from the 
generator is a contingency which must be planned for in the event of a 
partial or complete system malfunction. The present invention depends upon 
gravity for retraction, and includes an emergency cable (the electrical 
and pneumatic cable bundle covered with a Kevlar sheath) to serve as a 
contingency recovery method. The cable 87 is securely attached within the 
head of the unit and extends the length of the device and out the access 
port 5. Therefore, the device can be forcibly extracted from the generator 
by lowering the device and retrieving the device with no lost parts from 
the device left in the generator after removal is complete. For example, 
use of exposed screws is avoided. When screws must be present they have 
retainer clips or safety wires attached. Where screws must be used it is 
preferable to recess the screws and fill the holes with a suitable filler 
to lock in the screws. Preferably, the emergency removal can be 
accomplished whether or not the wand 16 or 17 is in its extended position. 
Any workable camera may be used in connection with the present invention 
inspection device. Preferred devices are the charge coupled device (CCD) 
video cameras, for example as described in U.S. Pat. No. 5,265,129 which 
is incorporated by reference herein. The range of camera view can be 
increased to desired specifications by patching multiple cameras to the 
camera head on the wand 16 and elsewhere throughout the device including 
on the telescoping stem such that every aspect of the device can be viewed 
on the monitors. The materials selected for the device including the 
camera housings must be able to withstand harsh environmental conditions. 
It is understood that the camera will withstand excessive temperatures of 
at least about 50.degree. C., and may include passive or active cooling 
means. The probe camera cable system is preferably completely encased in a 
housing along the wand, preferably having constant cable tension during 
probe (wand) retraction. The cameras, according to one preferred 
embodiment, and as shown in the drawings, are preferably integrated into 
the wand along with the required lighting units as part of the camera 
structure. Preferred cameras are modified Toshiba QN401E 1/4" cameras, 
although other CCD cameras may be modified for use with the present 
invention as would be understood by one skilled in the electronics field. 
The primary function of the probe 20 is to house the cameras 400 along with 
supporting lighting fixtures 402, 404. The primary function of the wand 16 
or 17 is to position the camera 400 for inspection. The wand 16 or 17 is 
preferably telescoping and wired to a computer to send and receive 
information for proper positioning. The wand preferably has an 
electromagnetic clutch attached to a de-couple drive, but could use any 
drive mechanism that can reliably move and position the wand as would be 
understood to one skilled in the field of drive mechanics. 
The device of the present invention will facilitate inspection of any 
closed vessel where maneuverability is critical and hard-to reach areas 
requiring visual inspection are required to keep the vessel in service. 
The entire device is designed to be a non-invasive device in the unlikely 
event of malfunction where careful retrieval and complete device removal 
would be required. 
As already mentioned, an in-bundle probe delivers the camera to the desired 
tube row with the device having at least one rotating joint and at least 
one telescoping vertical and at least one horizontal member. 
Many other modifications and variations of the present invention are 
possible to the skilled practitioner in the field in light of the 
teachings herein. It is therefore understood that, within the scope of the 
claims, the present invention can be practiced other than as herein 
specifically described.