Apparatus for remotely decontaminating reactor cavity walls

Apparatus and method for remotely decontaminating, cleaning, scrubbing or polishing the surface of a nuclear reactor cavity wall. The apparatus includes brushes for scrubbing the surface and a drive mechanism for rotating the brushes. The drive mechanism may be a gear drive, a chain and sprocket drive, or a belt and pulley drive. Connected to the brushes and enclosing the drive mechanism is an sealable enclosure. A drive axle extends from the drive mechanism to a motor which is disposed in a housing connected to and located proximate the enclosure. The motor is capable of rotating the drive axle which in turn operates the drive mechanism for rotating the brushes. A fluid dispenser is also provided for dispensing a cleaning agent against the surface to enhance the cleaning ability of the brushes. A container is attached to the housing for receiving ballast therein so that the brushes may exert a bearing pressure against the surface of the wall for suitably scrubbing the surface. Connected to the housing are lifting lugs for receiving lift cables which are connected to an overhead crane. The overhead crane is used to raise and lower the apparatus and to horizontally position the apparatus along the surface of the wall to be decontaminated.

BACKGROUND OF THE INVENTION 
This invention generally relates to apparatus and methods for cleaning 
surfaces and more particularly relates to an apparatus and a method for 
remotely decontaminating, cleaning, or polishing the surfaces of nuclear 
reactor cavity walls, wherein the apparatus includes brush means for 
cleaning the surface of the wall, drive means connected to the brush means 
for rotating the brush means to clean an area of the surface of the wall, 
means connected to the brush means for simultaneously orbiting the brush 
means as the brush means rotates to clean a larger area of the surface of 
the wall. The apparatus may alternatively include a polisher for polishing 
the surface of the wall. 
A nuclear reactor, which is a device for producing heat by fissioning 
nuclear fuel, must be periodically refueled during what is commonly 
referred to as a refueling outage. Not only is the reactor refueled during 
the refueling outage, but maintenance activities may also be performed at 
that time. During the refueling outage, workmen come into close proximity 
to the reactor cavity, in which the reactor resides, for refueling and for 
maintaining the reactor. However, during operation of the nuclear reactor, 
the reactor cavity walls, which typically have a stainless steel facing, 
may have become contaminated with radioactive particulate matter adhering 
to the walls. Hence, to reduce the amount of radiation exposure to the 
workmen, the reactor cavity walls are typically cleaned before refueling 
and maintaining the reactor. 
Decontamination of reactor cavity walls has been obtained by lowering a 
workman into the reactor cavity to clean the cavity walls. In one method 
of cleaning the cavity walls, the workman uses cloths soaked in a suitable 
cleaner, such as acetone, to manually wipe the surface of the reactor 
cavity wall for removing the radioactive contaminants. Another method of 
cleaning reactor cavity walls includes lowering a workman, equipped with a 
high pressure water hose, into the reactor cavity. The workman then holds 
the high pressure water hose and directs high pressure water spray against 
the surface of the wall to remove the contaminants. However, the high 
pressure water spray impinging the surface of the wall may direct some of 
the radioactive contaminants from the wall onto the workman, thereby 
increasing the risk of radiation exposure to the workman. In any case, 
both methods recited above for decontaminating the walls of the reactor 
cavity are necessarily time consuming and may result in increased risk of 
radiation exposure to the workman because workman must be lowered into the 
cavity. Moreover, reducing the time the workman remains in the cavity, in 
order to reduce the amount of radiation exposure to that workman, will 
necessarily result in less surface area being adequately cleaned. In 
addition, using several workmen to clean the reactor cavity, in order to 
reduce the radiation exposure to any one workman, is impractical for 
reasons including increased labor and material costs to perform the 
decontamination. Therefore, it would be desirable if the reactor cavity 
walls were cleaned remotely without the need for a workman in the reactor 
cavity. 
A device for remotely decontaminating a nuclear reactor cavity is disclosed 
by U.S. Pat. No. 4,436,694 issued Mar. 13, 1984 in the name of Michael 
Vassalotti et al. entitled "Nuclear Reactor Cavity Decontamination 
Machine". The Vassalotti et al. patent is directed towards a device for 
decontaminating the walls of boiling water reactor cavities and storage 
pits. This patent discloses an apparatus comprising a chassis which has 
wheels in rolling contact with the floor of the cavity and first and 
second curb wheels in rolling contact with a raised curb surrounding the 
periphery of the cavity. The apparatus directs high pressure water spray 
onto the surface of the wall for cleaning the wall. The apparatus is run 
along the curb, thereby cleaning a horizontal strip of the wall. This 
operation is repeated until the entire wall is cleaned. The Vassalotti et 
al. patent, however, does not appear to disclose brush means for cleaning 
the surface of the wall. Moreover, the Vassalotti et al. patent does not 
appear to disclose an apparatus for suitably polishing the surface of the 
cavity wall. 
Another device for remotely cleaning reactor cavity walls is disclosed by 
U.S. Pat. No. 4,351,132 issued Sept. 28, 1982 in the name of Roland Molin 
entitled "Machine for Cleaning Vertical or Inclined Surfaces". The Molin 
device comprises at least one roller brush supported by a frame and 
further comprises a fluid distribution means arranged on the frame for 
directing jets toward the cavity wall. Although the Molin patent may 
disclose at least one roller brush and fluid distribution means, the Molin 
patent does not appear to disclose brush means which rotates for cleaning 
an area of the surface and which also simultaneously orbits as it rotates 
for cleaning a larger area of the surface of the wall. Moreover, the Molin 
patent does not appear to disclose an apparatus for suitably polishing the 
surface of the cavity wall. 
Therefore, while the prior art discloses various devices for remotely 
cleaning reactor cavity walls, the prior art does not appear to disclose 
an apparatus and a method for decontaminating or cleaning the surface of 
reactor cavity walls, wherein the apparatus includes brush means for 
cleaning the surface, drive means connected to the brush means for 
rotating the brush means to clean an area of the surface and means 
connected to the brush means for simultaneously orbiting the brush means 
as the brush means rotates to clean a larger area of the surface of the 
wall. Moreover, the prior art does not appear to disclose a polisher for 
polishing the surface of the cavity wall. 
Consequently, what is needed are an apparatus and a method for 
decontaminating, cleaning or polishing the surface of reactor cavity 
walls, wherein the apparatus includes brush means for cleaning the surface 
of the wall, drive means connected to the brush means for rotating the 
brush means to clean an area of the surface of the wall, means connected 
to the brush means for simultaneously orbiting the brush means as the 
brush means rotates to clean a larger area of the surface of the wall. The 
apparatus may alternatively include a polisher for polishing the surface 
of the cavity wall. 
SUMMARY OF THE INVENTION 
Disclosed herein are an apparatus and a method for decontaminating, 
cleaning or polishing the surface of reactor cavity walls, wherein the 
apparatus includes brush means for cleaning the surface of the wall, drive 
means connected to the brush means for rotating the brush means to clean 
an area of the surface of the wall, means connected the brush means for 
simultaneously orbiting the brush means as the brush means rotates to 
clean a larger area of the surface of the wall. Moreover, the apparatus 
may alternatively include a polisher for polishing the surface of the 
cavity wall. 
More specifically, the apparatus comprises brush means including a first 
brush and a second brush for decontaminating, cleaning or scrubbing the 
surface of the cavity wall. The first brush and the second brush are 
attached to a cylindrical first collet and a cylindrical second collet, 
respectively, wherein each collet has a longitudinal slot therethrough. 
The first collet and the second collet each defines a cavity therein for 
slidably receiving the proximal end portion of an associated first shaft 
and an associated second shaft, respectively. Each shaft has a proximal 
end portion having a pin perpendicularly extending therefrom through the 
slot of its associated collet for rotating the collet and thus for 
rotating each associated brush when its associated shaft rotates. 
Moreover, the proximal end portion of each shaft terminates in a circular 
flange slidably disposed in the associated cavity of each collet. 
Interposed between each flange and each brush is a spring for continuously 
biasing each brush against the surface of the wall, so that the surface of 
the wall is suitably scrubbed. Each shaft also has a distal end portion 
connected to suitable drive means for rotating each shaft and thus for 
rotating each brush to which each shaft is connected. The drive means may 
be a gear drive, a chain drive or a belt drive. The drive means is 
surrounded by an enclosure for sealably enclosing the drive means. 
Connected to the drive means is the proximal end portion of a drive axle 
for operating the drive means, which is disposed in the enclosure. The 
enclosure is freely rotatable in a 360 degree plane on and perpendicular 
to an axis extending longitudinally through the drive axle. The drive 
axle, which also has a distal end portion, includes a conduit therein 
extending from the proximal end portion of the drive axle to near the 
distal end portion of the drive axle for conducting a liquid cleaning or 
wetting agent, such as deionized or demineralized water, therethrough. In 
fluid communication with the conduit in the drive axle is a liquid supply 
coupler which in turn is connected to a fluid reservoir for supplying 
liquid cleaning or wetting agent to the conduit. The conduit is in fluid 
communication with fluid dispensing means, such as jet nozzles connected 
to the enclosure, for dispensing the cleaning or wetting agent against the 
surface of the wall for wetting the wall to enhance the cleaning 
efficiency of the brushes. Of course, connected to the distal end portion 
of the drive axle is a motor for rotating the drive axle. The motor, 
distal end portion of the drive axle and the liquid supply coupler are 
disposed in a housing disposed proximate the enclosure for sealably 
enclosing the motor, distal end portion of the drive axle and liquid 
supply coupler. 
Attached to the exterior of the housing is a container for receiving a 
predetermined amount of ballast therein, which ballast may be lead bricks 
or the like. Moreover, any free volume surrounding the motor disposed in 
the housing may also be filled with ballast. The ballast controls the 
amount of pressure exerted by the brushes against the wall. Also attached 
to the housing are horizontal lift bars adapted to receive lifting lugs 
slidably adjustable along each lift bar. A lifting lug may also be 
attached to the container. Each lifting lug is capable of receiving a lift 
cable. Each lift cable is connected to an overhead crane for raising and 
lowering the apparatus and for horizontally positioning the apparatus 
along the surface of the wall. By placing sufficient ballast into the 
container and/or the housing, a principal angular moment of inertia into 
the surface of the wall is created. In addition, because the free volume 
surrounding the motor may also be filled with the motor may also be filled 
with additional ballast, the angular moment of inertia can be adjusted or 
changed by slidably adjusting the lifting lugs along the lift bars, thus 
enabling the brushes to make full contact with the surface of the wall to 
be scrubbed. 
The method of the invention may first include disposing ballast into the 
container attached to the housing and disposing additional ballast into 
the free volume surrounding the motor for exerting sufficient pressure 
against the surface of the wall so that the surface may be suitably 
cleaned or scrubbed. The method of the invention may further include 
operating the overhead crane so that the apparatus is lowered into the 
reactor cavity such that the brushes are at the top of the area of the 
surface of the wall to be decontaminated. Cleaning agent may then be 
supplied to the conduit in the drive axle for directing the cleaning agent 
against the surface of the wall. The motor is operated for rotating the 
drive axle which in turn operates the drive means for rotating the 
brushes. As the brushes rotate an asymmetrical thrust is created that 
causes the freely rotatable enclosure to which the brushes are connected 
to rotate for orbiting the brushes on the surface. Rotating the brushes 
will clean an area of the surface of the wall; however, simultaneous 
rotation and orbiting of the brushes will clean a larger area of the 
surface of the wall. The crane may be operated to horizontally translate 
the apparatus so that a horizontal strip of the wall is sufficiently 
cleaned or decontaminated. The apparatus may then be lowered to clean or 
decontaminate another horizontal strip of the surface, the second 
horizontal strip overlapping the first horizontal strip. This process can 
be repeated until the entire surface of the wall is cleaned or 
decontaminated. After the surface of the wall is cleaned or 
decontaminated, the apparatus is removed from the reactor cavity via the 
overhead crane. 
Moreover, the brush means may include a polisher connected to the first 
shaft and the second shaft for polishing the surface of the wall which may 
be stainless steel. As the first shaft and the second shaft rotate, the 
first shaft and the second shaft are capable of translating the polisher 
in an elliptical orbit in a plane about and perpendicular to an axis 
equidistant between the first and second shafts. 
Therefore, an object of the instant invention is to provide an apparatus 
for remotely cleaning a surface, comprising brush means for cleaning the 
surface, drive means connected to the brush means for rotating the brush 
means to clean an area of the surface, and means connected to the brush 
means for simultaneously orbiting the brush means as the brush means 
rotates to clean a larger area of the surface. 
Another object of the invention is to provide an apparatus for polishing 
the surface, wherein the brush means is a polisher for polishing the 
surface. 
A further object of the invention is to provide an apparatus for 
decontaminating the surface of a reactor cavity wall, comprising a first 
shaft having a proximal end portion and a distal end portion, a second 
shaft having a proximal end portion and a distal end portion, a first 
brush connected to the proximal end portion of the first shaft, a second 
brush connected to the proximal end portion of the second shaft, drive 
means connected to the distal end portions of the first shaft and the 
second shaft for rotating the first shaft and the second shaft so that the 
first brush and the second brush rotate for decontaminating an area of the 
surface, an enclosure surrounding the drive means and connected to the 
first shaft and to the second shaft for orbiting the first shaft and the 
second shaft so that the first brush and the second brush simultaneously 
orbit as the first brush and second brush rotate for decontaminating a 
larger area of the surface of the wall. 
Yet another object of the invention is to provide an apparatus and a method 
for decontaminating the surface of the wall, wherein the apparatus 
includes means attached to the apparatus for pressing the brushes against 
the surface of the wall. 
These and other objects of invention will become apparent to those skilled 
in the art upon a reading of the following detailed description when taken 
in conjunction with the drawings wherein there is shown and described 
illustrative embodiments of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment of The Invention 
Disclosed herein are an apparatus and method for remotely decontaminating, 
cleaning, scrubbing, or polishing surfaces such as the surface of reactor 
cavity walls. 
Referring to FIGS. 1 and 2, there is illustrated the apparatus of the first 
embodiment of the invention, generally referred to as 10, operatively 
disposed for decontaminating, cleaning or scrubbing a surface 20 belonging 
to a substantially vertical nuclear reactor cavity wall 30, which may be 
stainless steel. As described in more detail hereinafter, apparatus 10 
comprises orbiting rotating brush means, generally referred to as 40, for 
scrubbing surface 20. Brush means 40 may include at least two spaced-apart 
mounting disks, such as a first mounting disk 50a for mounting thereon an 
associated first brush mat 60a and a second mounting disk 50b for mounting 
thereon an associated second brush mat 60b. First brush mat 60a and second 
brush mat 60b may be disk-shaped and may be a fibrous material. First 
brush mat 60a and second brush mat 60b may be attached to their associated 
mounting disks 50a and 50b by any suitable means, such as by a suitable 
adhesive. By way of example only, the fibrous material comprising brush 
mats 60a and 60b may be a coarse surface conditioning material with a 
"SCOTCH MATE DUAL LOCK PSA" belt back material marketed as "SCOTCH BRITE" 
and available from the Minnesota Mining and Manufacturing Company located 
in Saint Paul Minnesota, U.S.A. Mounted on first brush mat 60a and second 
brush mat 60b are an associated disk-shaped first pad 70a and a second pad 
70b, respectively. First pad 70a and second pad 70b may have a 
multiplicity of densely packed substantially rigid finger-like members 
(not shown) perpendicular to and protruding a small distance from each 
side of pads 70a and 70b. The fingers protruding from one side of pads 70a 
and 70b intimately engage the fibrous material of their respective brush 
mats 60a and 60b for attaching pads 70a and 70b to their respective brush 
mats 60a and 60b. Alternatively, each side of pads 70a and 70b may be a 
"VELCRO"-type material or the like. The "VELCRO"-type material on one side 
of pads 70a and 70b can be used to adhere pads 70a and 70b to brush mats 
60a and 60b. 
Still referring to FIGS. 1 and 2, mounted on first pad 70a is an associated 
disk-shaped first brush 80a for scrubbing surface 20. Moreover, mounted on 
second pad 70b is an associated disk-shaped second brush 80b for scrubbing 
surface 20. First brush 80a and second brush 80b may be a fibrous material 
such as "SCOTCH BRITE" available from Minnesota Mining and Manufacturing 
Company. As recited hereinabove, the fingers protruding from the one side 
of pads 70a and 70b intimately engage the fibrous material of their 
respective brush mats 60a and 60b. The protruding fingers belonging to the 
other side of pads 70a and 70b not engaging brush mats 60a and 60b 
intimately engage the fibrous material belonging to each associated brush 
80a and 80b for removably attaching brushes 80a and 80b to pads 70a and 
70b, respectively. Alternatively, the "VELCRO"-type material recited 
hereinabove may be used to removably adhere brushes 80a and 80 b to pads 
70a and 70b, respectively. First brush 80a and second brush 80b are 
removably attached to first pad 70a and second pad 70b, respectively, so 
that worn brushes can be easily peeled away from pads 70a and 70b and 
replaced by new brushes, if desired. It will be appreciated that other 
means may be used for removably attaching brushes 80a and 80b to mounting 
disks 50a and 50b. Thus, the structures recited hereinabove for attaching 
brushes 80a and 80b to mounting disks 50a and 50b are merely examples. It 
will be understood that brush means 40 comprises the combination of 
mounting disks 50a and 50b, brush mats 60a and 60b, pads 70a and 70b, and 
brushes 80a and 80b. As described in more detail hereinbelow, brush means 
40 is not only capable of rotating but is also capable of simultaneously 
orbiting in a plane perpendicular to an axis perpendicular to and 
equidistant between mounting disks 50a and 50b. That is, brushes 80a and 
80b are capable of individually rotating and are also capable of 
simultaneously orbiting about the axis equidistant between mounting disks 
50a and 50b. 
Turning now to FIGS. 3, 4, and 4A, attached to first mounting disk 50a and 
to second mounting disk 50b are an associated first brush biasing 
assembly, generally referred to as 90a and an associated second brush 
biasing assembly, generally referred to as 90b, respectively, for biasing 
brush means 40 against surface 20. First brush biasing assembly 90a 
comprises an associated hollow generally cylindrical first collet 100a 
having a proximal end 110, a distal end 120 and a longitudinal collet wall 
125 (see FIG. 4). Moreover, second brush biasing assembly 90b comprises an 
associated hollow generally cylindrical second collet 100b having a 
proximal end 112, a distal end 122 and a longitudinal collet wall 127 (see 
FIG. 4A). Proximal end 110, distal end 120 and collet wall 125 define a 
generally cylindrical cavity 130 in collet 100a. Similarly, proximal end 
112, distal end 122 and collet wall 127 define a generally cylindrical 
cavity 130 in collet 100b. Each collet 100a and 100b is attached, such as 
by welding, at their respective proximal ends 110 and 112 to their 
associated mounting disks 50a and 50b. Moreover, distal ends 120 and 122 
are each provided with a hole 135 therethrough for reasons to be recited 
presently. Disposed in each cavity 130 is biasing means, such as a 
helically coiled spring 140, for biasing brush means 40 against surface 
20. In addition, formed through each wall 125 and 127 is a longitudinal 
slot 150. Slot I50 extends from each proximal end 110 and 112 to near 
distal ends 120 and 122, respectively, for reasons more fully described 
hereinafter. 
With particular reference to FIGS. 4 and 4A, slidably extending through 
hole 135 in collet 100a and 110b are an associated generally cylindrical 
first shaft 160a and an associated generally cylindrical second shaft 
160b, respectively, for rotating brush means 40. Shafts 160a and 160b, 
which are substantially parallel, have proximal end portions 165a and 
165b, respectively, terminating in a circular flange 170 slidably disposed 
in cavity 130. Flange 170 has a bearing surface 180 thereon for bearing 
against spring 140, which reposes on bearing surface 180. Formed 
integrally with each proximal end portion 165a and 165b and perpendicular 
thereto is a pin 190, which may be generally cylindrical, of width 
slightly smaller than the smallest width of slot 150 for sliding or 
reciprocating in slot 150 when collets 100a and 100b slide or reciprocate 
along shafts 160a and 160b. It will be understood that collets 100a and 
100b will slide or reciprocate along shafts 160a and 160b as brushes 80a 
and 80b traverse an uneven surface 20. Pin 190 perpendicularly extends 
from proximal end portion 165a and 165b through slot 150 so that pin 190 
will contact and exert a force against an edge of slot 150 for rotating 
collets 100a and 100b as shafts 160a and 160b rotate. As each collet 100a 
and 100b rotates, their associated mounting disks 50a and 50b will also 
rotate because first collet 100a and second collet 100b are attached to 
first mounting disk 50a and to second mounting disk 50b at their 
respective proximal ends 110 and 112. Of course, first brush 80a and 
second brush 80b will rotate when their associated first mounting disk 50a 
and second mounting disk 50b rotate because brushes 80a and 80b are 
connected to mounting disks 50a and 50b in the manner described 
hereinabove. As stated hereinabove, each collet 100a and 100b also has 
hole 135 in their respective distal ends 120 and 122. Hole 135 is formed 
in distal ends 120 and 122 for slidably receiving proximal end portion 
165a and 165b of shafts 160a and 160b, respectively. It will be 
appreciated that it is important that brush means 40 remain in intimate 
contact with surface 20 so that surface 20 may be suitably scrubbed. 
Therefore, even if surface 20 is uneven, spring 140 is capable of 
continuously biasing brush means 40 into intimate contact with surface 20 
for suitably scrubbing surface 20. In this regard, spring 140 will exert a 
force against mounting disks 50a and 50b because spring 140 is interposed 
between mounting disks 50a and 50b and flange 170. Because first shaft 
160a and second shaft 160b are slidably disposed through hole 135, collets 
100a and 100b will slide and reciprocate along first shaft 160a and second 
shaft 160b, respectively, as brush means 40 traverses uneven surface 20. 
The sliding and reciprocating action of collets 100 a and 100b in 
combination with the force exerted by spring 140 allow first brush 80a and 
second brush 80b to remain in intimate contact with surface 20 though 
surface 20 may be uneven. Therefore, even if surface 20 is uneven, the 
instant invention will allow it to be suitably scrubbed. 
As best seen in FIG. 4B, first shaft 160a and second shaft 160b have a 
distal end portion 210a and 210b, respectively, terminating inside a 
sealed chamber 220 defined by a brush arm, generally referred to as 222. 
Brush arm 222 comprises a sealed enclosure 230, which may be stainless 
steel or like material resistant to corrosion by deionized or 
demineralized water. Enclosure 230 has six mutually perpendicular panels 
including a top panel 234 (see FIGS. 7 and 14), a bottom panel 235, a rear 
side panel 236 and a front side panel 237. Thus, enclosure 230 (i.e., the 
brush arm 222) may be box-shaped and has a first opening 240a in front 
side panel 237 for passage therethrough of distal end portion 210a 
belonging to first shaft 160a. Enclosure 230 also has a second opening 
240b in front side panel 237 for passage therethrough of distal end 
portion 210b belonging to second shaft 160b. Distal end portions 210a and 
210b belonging to first shaft 160a and to second shaft 160b, respectively, 
are suitably rotatably connected to rear side panel 236 so that first 
shaft 160a and second shaft 160b are capable of rotating although 
connected to rear side panel 236. Enclosure 230 is capable of freely 
rotating in a 360 degree plane perpendicular to an axis of rotation 
parallel to and generally equidistant between shafts 160a and 160b. In 
this regard, enclosure 230 rides on a main bearing 238 which in turn rides 
on a drive axle 430 for allowing enclosure 230 to be freely rotatable. As 
described in more detail hereinafter, rotation of brushes 80a and 80b on 
surface 20 will generate a couple of the forces of which will allow 
brushes 80a and 80b to orbit in the plane perpendicular to the axis 
parallel to and generally equidistant between shafts 160a and 160b. 
Referring to FIGS. 3, 4B and 5, disposed in enclosure 230 is a drive 
mechanism or drive means, such as a gear drive generally referred to as 
233, for rotating brush means 40. Gear drive 233 comprises a generally 
cylindrical first spindle 250, disposed in chamber 220 and adjacent to 
distal end portion 210a of first shaft 160a. First spindle 250 is 
rotatably attached to rear side panel 236. Gear drive 233 also comprises a 
generally cylindrical second spindle 260 disposed in chamber 220 and 
adjacent to first spindle 250. Second spindle 260 is also rotatably 
attached to rear side panel 236. Moreover, gear drive 233 comprises a 
generally cylindrical third spindle 270 disposed in chamber 220 and 
adjacent to distal end portion 210b of second shaft 160b. Third spindle 
270 is rotatably attached to rear side panel 236. In addition, gear drive 
233 further comprises a generally cylindrical fourth spindle 280 disposed 
in chamber 220 and adjacent to third spindle 270. Fourth spindle 280 is 
rotatably attached to rear side panel 236. 
Still referring to FIGS. 3, 4B and 5, gear drive 233 further includes a 
first gear 290 having a plurality of first gear teeth 300 therearound. 
First gear 290 surrounds distal end portion 210a of first shaft 160a and 
is connected thereto for rotating first shaft 160a. Gear drive 233 also 
includes a second gear 310 surrounding first spindle 250 and connected 
thereto. Second gear 310 has a plurality of second gear teeth 320 
therearound for matingly engaging first gear teeth 300 belonging to first 
gear 290. Gear drive 233 further includes a third gear 330 surrounding 
second spindle 260 and connected thereto. Third gear 330 has a plurality 
of third gear teeth 340 therearound for matingly engaging second gear 
teeth 320 belonging to second gear 310. In addition, gear drive 233 
includes a fourth gear 350 having a plurality of fourth gear teeth 360 
therearound. Fourth gear 350 surrounds distal end portion 210b of second 
shaft 160b and is connected thereto for rotating second shaft 160b. 
Moreover, gear drive 233 includes a fifth gear 370 surrounding third 
spindle 270 and connected thereto. Fifth gear 370 has a plurality of fifth 
gear teeth 380 therearound for matingly engaging fourth gear teeth 360 
belonging to fourth gear 350. Gear drive 233 further includes a sixth gear 
390 surrounding fourth spindle 280 and connected thereto. Sixth gear 390 
has a plurality of sixth gear teeth 390 therearound for matingly engaging 
fifth gear teeth 380 belonging to fifth gear 370. As shown in FIGS. 3, 4B 
and 5, interposed between third gear 330 and sixth gear 390 is a main gear 
410 having a plurality of main gear teeth 420 therearound for matingly 
simultaneously engaging third gear teeth 340 and sixth gear teeth 400. 
Thus, when main gear 410 rotates, first gear 290, second gear 310, third 
gear 330, fourth gear 350, fifth gear 370 and sixth gear 390 also rotate. 
Moreover, it will be appreciated that the configuration of gear drive 233 
ensures that the direction of rotation (i.e., clockwise or 
counter-clockwise) of first gear 290 and fourth gear 350 will be in the 
same direction. That is, first shaft 160a, to which first gear 290 is 
connected, and second shaft 160b, to which fourth gear 350 is connected, 
will rotate in the same direction. Thus, first brush 80a, to which first 
shaft 160a is connected, and second brush 80b, to which second shaft 160b 
is connected, will rotate in the same direction to generate a couple for 
orbiting brushes 80a and 80b in a plane perpendicular to the axis parallel 
to and equidistant between shafts 160a and 160b. The rotation of brushes 
80a and 80b will simultaneously cause brushes 80a and 80b to orbit about 
the axis defined immediately hereinabove. That is, brushes 80a and 80b are 
connected via shafts 160a and 160b to enclosure 230, which enclosure 230 
is capable of freely rotating (i.e., with relatively low kinematic 
friction) on drive axle 430. Because brushes 80a and 80b rotate in the 
same direction, they each acquire an angular momentum pointing in the same 
direction as the direction of rotation. Thus, enclosure 230 will rotate in 
the same direction as the direction of angular momentum (i.e., as the 
direction of rotation of brushes 80a and 80b) when brushes 80a and 80b 
intimately engage surface 20. The rotation of enclosure 230 will cause 
brushes 80a and 80b, to which enclosure 230 is connected, to orbit in a 
plane perpendicular to the axis parallel to and equidistant between shafts 
160a and 160b. 
Referring to FIG. 3 and 4B, extending through rear side panel 236 and into 
chamber 230 is a rotatable and generally cylindrical drive axle 430 having 
a proximal end portion 440 connected to main gear 410 for rotating main 
gear 410. Drive axle 430 may have a hollow portion longitudinally 
therethrough defining a conduit 450 (see FIG. 6) for reasons described 
hereinbelow. As shown in FIG. 3 and 4B, drive axle 430 also has a distal 
end portion 460 terminating in a compartment 470 defined by a sealed 
housing 480 which may be box-shaped and thus may have six mutually 
perpendicular sides including opposing parallel sides 482. Housing 480 may 
be stainless steel or like material resistant to corrosion by deionized or 
demineralized water. Disposed in compartment 470 is motor means, such as a 
variable speed or low speed, reversible high torque air operated motor 
490, for rotating drive axle 430. Motor 490 may be of variable speed for 
varying the speed of rotation of drive axle 430. Moreover, motor 490 may 
be reversible for reversing the direction of rotation of drive axle 430. A 
suitable motor 490 may be selected from those motors readily available in 
the art, such as a "MODEL DVl-U" air drive motor available from Pneumatic 
Systems, Incorporated located in Dallas, Texas, U.S.A. Moreover, extending 
from motor 490 is a motor shaft 500 for rotating drive axle 430. 
Interposed between and coupled to motor shaft 500 and to drive axle 430 is 
a drive coupling 510 for coupling motor shaft 510 to drive axle 430 so 
that drive axle 430 rotates as motor shaft 500 rotates. Attached to motor 
490 is an air supply line 520 for supplying air to motor 490 to operate 
motor 490 if motor 490 is an air operated motor. Also attached to motor 
490 is an air return line 530 for removing or conducting the air 
necessarily exhausted from the operation of motor 490. It will be 
understood that air supply line 520 and air return line 530 may be 
suitable hoses fabricated from a flexible material, such as rubber or the 
like. 
As best seen in FIGS. 3, 4B and 6, disposed in compartment 470 and 
sealingly surrounding drive axle 430 is a liquid supply coupler 540 for 
supplying a cleaning or wetting agent, such as deionized or demineralized 
water, to conduit 450. A suitable liquid supply coupler 540 may be 
selected from those available in the art, such as available from Flow 
Industries, Incorporated located in Kent, Washington, U.S.A. Connected to 
liquid supply coupler 540 is a liquid supply line 550 for supplying the 
cleaning or wetting agent to liquid supply coupler 540 and thence to 
conduit 450. It will be understood that liquid supply line 550 may be a 
suitable hose fabricated from a flexible material, such as rubber or the 
like. As described presently, conduit 450 conducts the wetting agent to 
surface 20 for dispensing the wetting agent against surface 20 to enhance 
the scrubbing effectiveness of brush means 40. In this regard, sealingly 
connected to proximal end 440 of drive axle 430 is a conduit manifold 560 
having a plenum chamber (not shown) therein in fluid communication with 
conduit 450. In fluid communication with the plenum chamber are a first 
tube 570 and a second tube 580 extending therefrom for conducting the 
wetting agent out of the plenum chamber. First tube 570 and second tube 
580 may be a suitable flexible plastic or the like. Disposed through and 
attached, such as by welding, in front side panel 237 are a first fixture 
590 and a second fixture 600 that are sealingly connected to first tube 
570 and to second tube 580, respectively, for receiving the wetting agent 
from tubes 570 and 580. First fixture 590 and second fixture 600, which 
are capable of conducting the wetting agent therethrough, may be hollow 
elbow pipe joints or the like. Sealingly attached to first fixture 590 is 
a first jet nozzle connection, 610, which may be generally tubular. 
Similarly, sealingly attached to second fixture 600 is a second jet nozzle 
connection 620, which may be generally tubular. First jet nozzle 
connection 610 and second jet nozzle connection 620 may be inclined at a 
predetermined angle with respect to front side panel 237 so that nozzle 
connections 610 and 620 are capable of redirecting the liquid wetting 
agent received from fixtures 590 and 600 at a predetermined angle with 
respect to front side panel 237 so that the wetting agent flowing through 
jet nozzle connections 610 and 620 substantially pass through the space 
between spaced-apart brushes 80a and 80b. Connected to first jet nozzle 
connection 610 and to second jet nozzle connection 620 are fluid 
dispensing means such as a first jet nozzle 630 and a second jet nozzle 
640, respectively, each for directing a jet spray of the wetting agent 
against surface 20. First jet nozzle 630 and second jet nozzle 640 are 
preferably capable of being adjustably inclined such that the liquid 
flowing through jet nozzles 630 and 640 substantially pass through the 
space defined by spaced-apart brushes 80a and 80b. Moreover, adjustably 
inclined jet nozzles 630 and 640 can be adjusted such that the liquid 
flowing through jet nozzles 630 and 640 will impinge and wet areas of 
surface 20 where brushes 80a and 80b will scrub. It is preferable that the 
wetting agent pass through the space between brushes 80a and 80b so that 
brushes 80a and 80b do not substantially intercept the wetting agent 
impinging surface 20. In this manner, more liquid will impinge surface 20 
because the path of fluid flow from first jet nozzle 630 and second jet 
nozzle 640 to surface 20 will not be substantially blocked or 
substantially intercepted by brushes 80a and 80b. Moreover, first jet 
nozzle 630 may have external threads thereon and first nozzle connection 
510 may have internal threads therein for sealingly threadably connecting 
first jet nozzle 630 and first nozzle connection 510. Similarly, second 
jet nozzle 640 may have external threads thereon and second nozzle 
connection 620 may have internal threads therein for sealingly threadably 
connecting second jet nozzle 640 and second nozzle connection 620. The 
threaded connection of first jet nozzle 630 and first nozzle connection 
510 will enable first jet nozzle 630 to be easily threadably exchanged 
with a differently configured first jet nozzle 630 having different flow 
characteristics (e.g., stream versus fine spray). Similarly, the threaded 
connection of second jet nozzle 640 and second nozzle connection 620 will 
enable second jet nozzle 640 to be easily threadably exchanged with a 
differently configured second jet nozzle 640 having different flow 
characteristics (e.g., stream versus fine spray). In this manner, the size 
of the fluid jet impinging surface 20 may be varied from a stream to a 
fine mist or spray by exchanging jet nozzles, if desired, so that a 
precise area of surface 20 impinged by the fluid jet is smaller or larger, 
respectively. Thus, first jet nozzle 630 and second jet nozzle 640 
function as adjustable variable fluid impinging means for adjustably 
variably impinging the fluid upon surface 20 because the angle of 
inclination of nozzles 630 and 640 can be adjusted and because the size of 
the fluid jet can be varied. 
Returning to FIG. 2, connected to each side 482 of housing 480 is an 
elongated lift rod or lift bar 650 for providing means for lifting 
apparatus 10. In this regard, adjustably slidably secured to each lift bar 
650 is a lifting lug 660 for lifting apparatus 10 and for balancing and 
tilting apparatus 10. Each lifting lug 660 is capable of being connected 
to a lift cable 670 (see FIG. 1) for lifting and for repositioning (i.e., 
vertically and horizontally) apparatus 10 along surface 20. 
Again referring to FIG. 2, attached to a top side 680 of housing 480 is a 
parallelepiped hollow container 690 having a front side 700 and a rear 
side 710 both sloping away from enclosure 230. Container 690 defines a 
hollow portion 720 for receiving a predetermined quantity of ballast (not 
shown) therein, such as lead bricks for balancing apparatus 10 against 
surface 20. As described in more detail hereinbelow, the ballast assists 
in maintaining brush means 40 in intimate contact with surface 20 by 
controlling the location of the center of gravity of apparatus 10. It will 
be understood that controlling the location of the center of gravity of 
apparatus 10 also controls the pressure of brushes 80a and 80b bearing 
against surface 20. The amount of ballast into container 690 may be varied 
for varying the pressure of brushes 80a and 80b bearing against surface 
20. Moreover, attached to container 690 may be another lifting lug 730 for 
lifting apparatus 10 and for tilting apparatus 10 into surface 20. It will 
be appreciated that lifting lugs 660 are capable of being repositioned 
along their respective lifting bars 650 by sliding lifting lugs 660 along 
their associated lifting bars 650 so that apparatus 10 can be balanced 
against surface 20 and/or tilted into surface 20. 
Referring now to FIGS. 1, 2, and 7, a plurality of casters 740 are provided 
for allowing apparatus 10 to glide or slide along surface 20 when 
apparatus 10 is repositioned (i.e., horizontally and vertically) on 
surface 20. Casters 740, which are preferably mounted on enclosure 230, 
may be generally spherical, disk-shaped or any suitable geometry for 
slidably contacting surface 20. Moreover, the material of casters 740 may 
be selected such that the coefficient of sliding friction of that material 
on the material comprising surface 20 is relatively low so that casters 
740 may easily slide along surface 20. In addition, the material and 
configuration of casters 740 may be selected such that casters 740 are 
incapable of substantially marring surface 20. It is important that 
surface 20 not become substantially marred because substantial marring of 
surface 20 may produce undesirable localized sites for deposition of 
radioactive particulate contaminates. Thus, casters 740 may be a suitable 
plastic material or the like. As described in more detail hereinafter, 
there may be four casters 740, wherein two casters 740 are spaced-apart 
and mounted on top panel 234 and two casters 740 are spaced-apart and 
mounted on bottom panel 235 of enclosure 230. Attached to each caster 740 
is a caster leg 750 (see FIG. 7) configured for attaching each caster 740 
to an associated caster support 760. Each caster support 760 is adjustably 
connected to its associated top panel 234 or bottom panel 235. Each caster 
leg 750, having the associated caster 740 connected thereto, may dispose 
caster 740 at an oblique angle with respect to surface 20 to aid in 
sliding apparatus 10 along surface 20. Moreover, each caster 740 in 
connected to its associated caster leg 750 such that it may swivel about 
the point where caster 740 is connected to caster leg 750 to aid in 
sliding apparatus 10 along surface 20. By way of example only, each caster 
740 may be approximately three inches in diameter. Moreover, each caster 
support 760 is individually positionable, as described hereinbelow, for 
positioning each caster 740 and for positioning brushes 80a and 80b 
against surface 20. Each caster support 760 has a deck flange 770 
mountable on its associated top panel 234 or bottom panel 235. 
Alternatively, casters 740 and caster supports 760 may be similarly 
mounted on the sides of enclosure 230. Deck flange 770 has an elongated 
aperture 780 therethrough capable of receiving an adjustable fastener 790 
for mounting caster support 740 on its associated top panel 234 or bottom 
panel 235. Fastener 790 may be a threaded screw having a threaded shank 
portion (not shown) that is threaded through an opposing hole (not shown) 
formed through top panel 234 or bottom panel 235. The threaded shank 
portion may terminate in a shank head larger than the width of elongated 
aperture 780 so that fastener 790 can not pass through aperture 780. Thus, 
the position of each caster 740 with respect to surface 20 may be adjusted 
by unthreading fastener 790 from its corresponding hole in enclosure 230, 
moving caster support 760 either toward or away from front panel 237, as 
desired, and rethreading fastener 790 into its corresponding hole in 
enclosure 230 such that each caster support 760 is then affixed to its 
associated top panel 234 or bottom panel 235. It is important that 
apparatus 10 have caster supports 760 which are capable of positioning 
each caster 740 with respect to surface 20, as described hereinabove, so 
that brushes 80a and 80b may be suitably positioned flush against surface 
20 for suitably scrubbing surface 20. 
Second Embodiment of The Invention 
Referring to FIGS. 8 and 9, there is shown the second embodiment of the 
invention. The second embodiment of the invention is substantially similar 
to the first embodiment of the invention except that the drive means is a 
chain drive, generally referred to as 800, rather than gear drive 233. 
Chain drive 800 comprises a generally cylindrical first sprocket 810 
having a plurality of first sprocket teeth 820 therearound for engaging a 
plurality of sprocket holes 830 defined by a first chain 840a. Chain drive 
800 further comprises a generally cylindrical second sprocket 850 having a 
plurality of second sprocket teeth 860 therearound for engaging sprocket 
holes 830 defined by a second chain 840b. Moreover, chain drive 800 also 
comprises a first main sprocket 870a and a second main sprocket 870b 
interposed between first sprocket 810 and second sprocket 850 for driving 
chains 840a and 840b and therefore for rotating first sprocket 810 and 
second sprocket 850. Main sprockets 870a and 870b have a plurality of main 
sprocket teeth 880a and 880b, respectively, therearound for engaging the 
associated sprocket holes 830 of chains 840a and 840b. As shown in FIGS. 8 
and 9, first chain 840a extends around first sprocket 810 and main 
sprocket 870a so that sprocket holes 830 simultaneously engage first 
sprocket teeth 820 and main sprocket teeth 880a. Similarly, second chain 
840b extends around second sprocket 850 and main sprocket 870b so that 
sprocket holes 830 simultaneously engage second sprocket teeth 860 and 
main sprocket teeth 880b. It will be understood that first sprocket 810, 
second sprocket 850 and main sprockets 870a and 879b simultaneously rotate 
in the same direction (i.e., either clockwise or counter-clockwise) 
depending on the direction of rotation of drive axle 430. It will be 
further understood that in this second embodiment of the invention, first 
sprocket 810 and second sprocket 850 circumscribe first shaft 160a and 
second shaft 160b, respectively. It will be appreciated that in this 
second embodiment of the invention, first spindle 250, second spindle 260, 
third spindle 270, and fourth spindle 280 belonging to the first 
embodiment of the invention are not used and thus may be eliminated for 
conserving space in enclosure 230 and for decreasing the weight of 
apparatus 10 which is suspended by lift cables 670. 
Third Embodiment of The Invention 
Referring to FIGS. 10 and 11, there is shown the third embodiment of the 
invention which is substantially similar to the first embodiment of the 
invention except that the drive means is a belt drive, generally referred 
to as 890, rather than gear drive 233. Belt drive 890 comprises a first 
pulley 900 having a generally V-shaped (in transverse cross section) 
groove 910 in the marginal edge thereof extending around the circumference 
of first pulley 900 for matingly receiving a substantially flexible first 
belt 920a. Belt 920a has a generally V-shaped transverse cross section for 
matingly engaging groove 910. Belt drive 890 further comprises a second 
pulley 930 having the V-shaped groove 910 in the marginal edge thereof 
extending around the circumference of second pulley 930 for matingly 
receiving a second belt 920b. Moreover, belt drive 890 also comprises a 
first main pulley 940a interposed between first pulley 900 and second 
pulley 930 for driving first belt 920a and therefore for rotating first 
pulley 900. First main pulley 940a has groove 910 extending around the 
circumference thereof for matingly receiving first belt 920a therein. As 
shown in FIGS. 10 and 11, first belt 920a extends around first pulley 900 
and first main pulley 940a for rotating first pulley 900. Belt drive 890 
further comprises a second main pulley 940b interposed between first 
pulley 900 and second pulley 930 for driving second belt 920b and 
therefore for rotating second pulley 930. As shown in FIGS. 10 and 11, 
first belt 920a extends around first pulley 900 and first main pulley 
940a. Similarly, second belt 920b extends around second pulley 930 and 
second main pulley 940b. It will be understood that first pulley 900, 
second pulley 930, and main pulleys 940a and 940b simultaneously rotate in 
the same direction (i.e., either clockwise or counter-clockwise) depending 
on the direction of rotation of drive axle 430. It will be further 
understood that in this third embodiment of the invention, first pulley 
900 and second pulley 930 circumscribe first shaft 160a and second shaft 
160b, respectively. In this third embodiment of the invention, first 
spindle 250, second spindle 260, third spindle 270, and fourth spindle 280 
belonging to the first embodiment of the invention are not used and thus 
may be eliminated for conserving space in enclosure 230 and for decreasing 
the weight of apparatus 10 which is suspended by lift cables 670. 
Fourth Embodiment of The Invention 
Referring to FIGS. 12 and 13, there is illustrated the fourth embodiment of 
the invention. The fourth embodiment of the invention is capable of 
polishing surface 20, which may be stainless steel or the like, to remove 
radioactive particulate matter and to improve the aesthetic appearance of 
surface 20 by producing a higher coefficient of reflectivity on surface 20 
so that a sheen is provided to surface 20. As described in more detail 
hereinbelow, this fourth embodiment of the invention is substantially 
similar to the first embodiment of the invention except that brush means 
40 is a polisher generally referred to as 950 for polishing surface 20 and 
except that first shaft 160a and second shaft 160b will translate polisher 
950 in an elliptical orbit in a plane perpendicular to the axis parallel 
to and equidistant between shafts 160a and 160b for suitably polishing 
surface 20. 
As shown in FIGS. 12 and 13, polisher 950 comprises a mounting platform 960 
for mounting thereon an associated mounting mat 970 which may be 
substantially rectangular. Mounting mat 970 may be a fibrous material. 
Mounting mat 970 may be attached to its associated mounting platform 960 
by any suitable means, such as by a suitable adhesive. Mounted on mounting 
mat 970 is an attachment layer 980. Attachment layer 980. may have a 
multiplicity of densely packed substantially rigid finger-like members 
(not shown) perpendicular to and protruding a small distance from the 
front and rear sides of attachment layer 980. The fingers protruding from 
the rear side of attachment layer 980 intimately engage the fibrous 
material of mounting mat 970 for attaching attachment layer 980 to 
mounting mat 970. Alternatively, the front and rear sides of attachment 
layer 980 may be a "VELCRO"-type material or the like. The "VELCRO"-type 
material on the rear side of attachment layer 980 can be used to adhere 
attachment layer 980 to mounting mat 970. 
Referring to FIG. 12, mounted on attachment layer 980 is an associated 
abrasive brush 990, which may be generally rectangular, for sufficiently 
abrading or polishing surface 20. Abrasive brush 990 may be a fibrous 
material such as "SCOTCH BRITE" available from the Minnesota Mining and 
Manufacturing Company. As described hereinabove, the fingers protruding 
from the rear side of attachment layer 980 intimately engage the fibrous 
material of mounting mat 970. The protruding fingers belonging to the 
front side of attachment layer 980 not engaging mounting mat 970 
intimately engage the fibrous material belonging to abrasive brush 990 for 
removably attaching abrasive brush 990 to attachment layer 980. 
Alternatively, the "VELCRO"-type material recited hereinabove may be used 
to adhere abrasive brush 990 to attachment layer 980. Abrasive brush 990 
is removably attached to attachment layer 980 so that a worn abrasive 
brush 990 can be easily removed and replaced by a new abrasive brush, if 
desired. It will be appreciated that several means may be used for 
removably attaching abrasive brush 990 to mounting platform 960 of which 
the structures recited hereinabove are merely examples. It will be 
understood that polisher 950 comprises the combination of mounting 
platform 960, mounting mat 970, attachment layer 980 and abrasive brush 
990. Moreover, it will be further understood that mounting mat 970, 
attachment layer 980 and abrasive brush 990 may be of the same material as 
mats 60a-60b, pads 70a-70b, and brushes 80a-80b (see FIG. 3), 
respectively, if desired. It will be appreciated that when polisher 950 is 
used to polish surface 20, supply of fluid to surface 20 is not necessary. 
Therefore, when apparatus 10 is used to polish surface 20, fluid need not 
be supplied through liquid supply line 550. 
As best seen in FIGS. 12 and 13, mounting platform 960 includes four 
mutually perpendicular marginal edges 1000, 1001, 1002 and 1003. Brush 
biasing assemblies 90a and 90b, which are attached to mounting platform 
960, may be disposed nearer to one marginal edge than to the other three 
marginal edges. As shown in FIG. 13, brush biasing assemblies 90a and 90b 
are disposed nearer to marginal edge 1002 than to marginal edges 1000, 
1001 and 1003. Alternatively, brush biasing assemblies 90a and 90b may be 
disposed nearer to two marginal edges (e.g., 1001 and 1002) than to the 
other two marginal edges (e.g., 1000 and 1003). This off-center location 
of brush biasing assemblies 90a and 90b allows polisher 950 to follow an 
elliptical orbit about an axis perpendicular to the front face of polisher 
950 and equidistant between shafts 160a and 160b. The elliptical orbit of 
polisher 950 will cause abrasive brush 990 to sufficiently abrade surface 
20 for polishing a preselected relatively large area of surface 20. 
Fifth Embodiment of The Invention 
Referring to FIGS. 14 and 15, there is shown the fifth embodiment of the 
invention. The fifth embodiment of the invention is substantially similar 
to the first embodiment of the invention except that first tube 570 and 
second tube 580 (see FIG. 3) are not used and may be replaced by a hollow 
spray pipe 1010, which may be generally T-shaped. The hollow portion of 
spray pipe 1010 is in fluid communication with the plenum chamber (not 
shown) in conduit manifold 560. Conduit manifold 560 has a fluid hole 1020 
for passage therethrough of the wetting agent flowing into conduit 
manifold 560 from conduit 450 (see FIG. 6). It will be understood that 
spray pipe 1010 is connected to fluid hole 1020 for passage of the wetting 
agent from conduit manifold 560 into spray pipe 1010. Spray pipe 1010 may 
be provided with a plurality of adjustably swivable spray nozzles 1030 
thereon for directing the wetting agent issuing therefrom onto surface 20. 
As shown in FIG. 14, spray pipe 1010 may be configured to spray an area of 
surface 20 larger than the area of surface 20 sprayable by first jet 
nozzle 630 and second jet nozzle 640 (see FIG. 3). 
Method of the First, Second, and Third Embodiments of the Invention 
The method of the first, second, and third embodiments of the invention 
comprises placing a predetermined amount of ballast (not shown), such as 
lead bricks or the like, into container 690 for suitably balancing 
apparatus 10 against surface 20 so that surface 20 is suitably scrubbed 
when apparatus 10 is operated. Placing ballast into container 690 will 
create a principal angular moment of inertia into surface 20. Moreover, 
ballast may also be placed into housing 480 in the free space surrounding 
motor 490, drive coupling 510, and liquid supply coupler 540. It will be 
understood that the ballast will relocate the center of gravity of 
apparatus 10 so that brushes 80a and 80b will provide a sufficient bearing 
pressure against surface 20, thus maintaining brushes 80a and 80b in 
intimate contact with surface 20. Because sufficient ballast may be placed 
in the space surrounding motor 490, drive coupling 510, and liquid supply 
coupler 540, container 690 may be deleted if desired. However, placing a 
predetermined amount of ballast into container 690 and into the space 
surrounding motor 490, drive coupling 510 and liquid supply coupler 540 
will more accurately control the relocation of the center of gravity of 
apparatus 10. The method of the first, second, and third embodiments of 
the invention further comprises positioning apparatus 10 opposite that 
portion of surface 20 to be remotely decontaminated, scrubbed or cleaned. 
In this regard, lift cables 670, which are attached to lifting lugs 660, 
are connected to an overhead crane (not shown). The overhead crane is then 
activated for moving apparatus 10, via lift cables 670, to the portion of 
surface 20 to be remotely scrubbed. Lifting lugs 660 are slidably adjusted 
along their associated lift bars 650 for balancing apparatus 10 so that 
brush means 40 is substantially flush with and abuts against surface 20 
for suitably scrubbing surface 20. Because ballast may also be placed in 
the space surrounding motor 490, drive coupling 510, and liquid supply 
coupler 540, the angular moment of inertia referred to hereinabove may be 
adjusted or changed by suitably sliding lifting lugs 660 along their 
associated lift bars 650. Suitably adjusting the angular moment of inertia 
enables brush means 40 to make full contact with and to bear against 
surface 20 for scrubbing surface 20. 
It will be understood that when brush means 40 is positioned against 
surface 20 in the manner recited hereinabove, casters 740 will repose 
against surface 20 for sliding on surface 20 and for positioning brush 
means 40 substantially flush against surface 20. Caster supports 760 are 
capable of being individually adjusted, if required, to position brush 
means 40 against surface 20. In this regard, any one of caster supports 
760 may be adjusted by unscrewing fastener 790 from aperture 780 and its 
associated hole, which hole may be in top panel 234 or bottom panel 235. 
Caster support 760 is then slidably translated either toward or away from 
surface 20 for moving caster 760, which is attached to caster support 760, 
either toward or away from surface 20. Thus, translating each caster 
support 760 toward or away from surface 20 can position brush means 40 
flush against surface 20 for allowing brush means 40 to suitably 
decontaminate or scrub surface 20. 
Once brush means 40 is positioned against surface 20, the wetting agent may 
be supplied to liquid supply line 550 and thus to conduit 450. The wetting 
agent supplied to conduit 450 will flow through conduit 450 to the plenum 
chamber (not shown) in conduit manifold 560 and then to first tube 570 and 
to second tube 580. The wetting agent that flows through first tube 570 
and through second tube 580 will flow through first fixture 590 and 
through second fixture 600, respectively. This wetting agent then flows 
from first fixture 590 and second fixture 600 through first nozzle 
connection 610 and second nozzle connection 620, respectively. Because 
first jet nozzle 630 and second jet nozzle 640 are connected to their 
respective first nozzle connection 610 and second nozzle connection 620, 
the wetting agent flowing through first nozzle connection 610 and through 
second nozzle connection 620 will also flow through first jet nozzle 630 
and through second jet nozzle 640. The wetting agent passing through first 
jet nozzle 630 and second jet nozzle 640 then passes through the space 
defined by spaced-apart brushes 80a and 80b and impinges surface 20 for 
wetting surface 20. It will be appreciated that wetting surface 20 will 
increase and enhance the cleaning or scrubbing effectiveness of brush 
means 40. 
Motor 490 is operated to generate torque for rotating drive axle 430 which 
is connected to motor 490. If motor 490 is an air operated motor, then 
motor 490 is operated by supplying compressed air to motor 490 via air 
supply line 520. Of course, the air supplied to motor 490 is necessarily 
exhausted from motor 490 through air return line 530. The rotation of 
drive axle 430 will operate the drive means which in turn will 
simultaneously rotate first shaft 160a and second shaft 160b. Shafts 160a 
and 160b will rotate in the same direction, either clockwise or 
counter-clockwise, due to the configuration of the drive means described 
hereinabove. As shafts 160a and 160b rotate, their associated first brush 
biasing assembly 90a and second brush biasing assembly 90b will also 
rotate because brush biasing assemblies 90a and 90b are connected to their 
associated shafts 160a and 160b. Rotation of first brush biasing assembly 
90a and second biasing assembly 90b will cause first brush 80a and second 
brush 80 b to rotate for scrubbing surface 20. 
It is important that brush means 40 remain in intimate contact with surface 
20 for suitably scrubbing surface 20. Therefore, even if surface 20 is 
uneven, each spring 140, which belongs to brush biasing assemblies 90a and 
90b, will bias brush means 40 into intimate contact with surface 20. That 
is, spring 140 will exert a force against mounting disks 50a and 50b 
because spring 140 is interposed between mounting disk 50a and 50b and 
each flange 170. 
As described hereinabove, first brush 80a and second brush 80b will rotate 
in the same direction due to the configuration of the drive means 
described hereinabove. Moreover, as brushes 80a and 80b rotate on surface 
20, they will cause enclosure 480 to rotate in the same direction as the 
direction of rotation of brushes 80a and 80b because enclosure 480 is 
freely rotatable in a plane perpendicular to the axis parallel to and 
generally equidistant between shafts 160a and 160b. As enclosure 480 
rotates in the manner described hereinabove, brushes 80a and 80b will 
orbit about the axis equidistant between brushes 80a and 80b. That is, as 
brushes 80a and 80b rotate or spin on the axes passing longitudinally 
through shafts 160a and 160b, respectively, an asymmetrical thrust will be 
created and cause enclosure 480 to rotate for orbiting brushes 80a and 
80b. Thus, brushes 80a and 80b will not only rotate for scrubbing an area 
of surface 20, they will also simultaneously orbit as brushes 80a and 80b 
rotate for scrubbing a larger area of surface 20. It will be understood 
that the orbiting feature of brushes 80a and 80b allow brushes 80a and 80b 
to scrub a surface area larger than the surface area that otherwise could 
be scrubbed if brushes 80a and 80b were not orbitable. Scrubbing a larger 
surface area per cleaning or decontamination pass will reduce the 
radiation exposure time to the operator of apparatus 10 because less time 
will be required to clean surface 20. Moreover, the disk shape of brushes 
80a and 80b will allow brushes 80a and 80b to clean the vertical and 
horizontal edge crevices (not shown) where the walls of the reactor cavity 
meet. 
After apparatus 10 has sufficiently scrubbed a portion of surface 20, 
apparatus 10 may be horizontally translated to another portion of surface 
20 by operating the overhead crane (not shown) to which cables 670 are 
connected. Apparatus 10 is then operated to scrub that portion of surface 
20 to which apparatus 10 has been translated. After apparatus 10 has 
scrubbed a preselected horizontal strip of surface 20 by passing 
horizontally along surface 20, it may be lowered or raised and then 
translated to scrub another horizontal strip of surface 20, the second 
horizontal strip overlapping the first horizontal strip. The above process 
can be repeated until all of surface 20 is suitably scrubbed. 
Method of the Fourth Embodiment of the Invention 
The method of the fourth embodiment of the invention polishes surface 20 
for removing particulate matter and for improving the aesthetic appearance 
of surface 20, which may be stainless steel. In the method of the fourth 
embodiment of the invention, the off-center location of shafts 80a and 80b 
translates polisher 950 in an elliptical orbit in a plane about an axis 
parallel to and equidistant between shafts 160a and 160b. In this method 
of the invention, a wetting agent need not be applied to surface 20, 
unless desired by the operator of apparatus 10. 
Method of the Fifth Embodiment of the Invention 
In the method of the fifth embodiment of the invention, the wetting agent 
flows from the plenum chamber of conduit manifold 560 to spray pipe 1010 
and thence to spray nozzles 1030 for wetting surface 20. Using spray pipe 
1010 can allow a larger area of surface 20 to be impinged with the wetting 
agent compared to using first jet nozzle 630 and second jet nozzle 640. 
Of course it will be understood that modifications and variations to the 
invention may be effected without departing from the spirit and scope of 
the novel concepts of the present invention. 
Therefore, this invention provides an apparatus and method for remotely 
decontaminating, cleaning, or scrubbing vertical surfaces, such as nuclear 
reactor cavity walls, wherein the apparatus includes brush means for 
cleaning an area of the surface of the wall, drive means connected to the 
brush means for rotating the brush means, means connected to the brush 
means for simultaneously orbiting the brush means as the brush means 
rotates to clean a larger area of the surface of the wall. Moreover, the 
apparatus may alternatively include a polisher for polishing the surface 
of the wall.