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Патент USA US3094480

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June 18, 1963
R. s. STONE ETAL
3,094,470
NUCLEAR REACTOR AND IRRADIATING SYSTEM
Filed Nov. 12, 1959
3 Sheets-Sheet 1
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June 18, 1963
R. s. STONE EI'AL
3,094,470
NUCLEAR REACTOR AND IRRADIATING SYSTEM
Filed Nov. 12, 1959
3 Sheets-Sheet 2
éyjvwwo, M10», down! 8215a‘.
5
June 18, 1963
R. s. STONE EI'AL
3,094,470
NUCLEAR REACTOR AND IRRADIATING SYSTEM
Filed Nov. 12, 1959
3 Sheets-Sheet 3
United States Patent Oil ice
1
3 094 470
NUCLEAR REACTOR Ami IRRADIATING SYSTEM
Richard S. Stone, Del Mar, and George P. Kraker, La
Jolla, San Diego, Calif., assignors to General Dynamics
Corporation, New York, N.Y., a corporation of Dela
ware
Filed Nov. 12, 1959, Ser. No. 852,505
6 Claims. (Cl. 204-1542)
3,094,470
Patented June 18, 1963
2
of radioactive isotopes can be produced, including the
short-lived radioactive isotopes which, as indicated above,
have heretofore been unavailable to industry; and ?nally,
the reactor should be available at a relatively moderate
cost.
An isotope-producing reactor capable of satisfying the
foregoing requirements is described in Stanley L. Koutz
et a1. patent application, Serial No. 744,364, ?led June 25,
1958, now Patent No. 3,072,549, and assigned to the as
The present invention relates generally to neutronic re~ 10 signee of the present invention. The present invention
is directed to an improvement of the invention set forth
actors and more particularly to a neutronic reactor which
in Serial No. 744,364.
is especially useful for producing radioactive isotopes.
It is a primary object of the present invention to provide
Radioactive isotopes are being used in increasing quan
a novel method and apparatus for simultaneously and uni
tities in research, industry and medicine. Radioactive
isotopes of half lives longer than 12 hours are mainly 15 formly irradiating a plurality of samples in an isotope
being supplied by the Atomic Energy Commission. Un
fortunately, radioactive isotopes having half lives of less
producing neutronic reactor. Additional objects and ad—
vantages will be apparent from a study of the following
description, and from the accompanying drawings,
wherein:
than 12 hours generally cannot be shipped from Atomic
Energy Commission production plants to a utilizing or
FIGURE 1 is a sectional view of a reactor constructed
ganization in time for practical use. There are roughly 20
in accordance with the present invention, with parts there
about 60 short-lived isotopes which can be easily pro
of broken away;
duced by an isotope-producing reactor facility which are,
FIGURE 2 is an enlarged plan view of the upper sur
in effect, unavailable for commercial use. Such short
face of the rotary specimen rack shown in FIGURE 1,
lived radioactive isotopes have certain inherent advantages,
particularly in tracer techniques, over longer-lived iso 25 with portions thereof cut away to show certain of the
inner mechanisms of the specimen rack;
topes. In this connection, in medical and biological uses
FIGURE 3 is a cross sectional view taken along the
of radioactive tracers, it is desirable to hold to a minimum
line 3—3 of FIGURE 2; and
the radiation dose administered to the system in which the
FIGURE 4 is an enlarged perspective view of the speci
tracer is used. It can be shown that, for a given activity
at the time the radioactive measurement is made, the small 30 men rack operating and indicating mechanism used in
connection with the reactor shown in FIGURE 1, with
est dosage is incurred by the system when the mean life
portions cut away to show certain of the interior mecha
of the radioactive tracer is equal to the time interval be
nism thereof.
tween the injection of the radioactive isotope and its meas
The illustrated embodiment of the invention comprises
urement. Also, it is possible to use radioactive isotopes
for certain production control applications only if the
residual activity a short time after production is su?icient
a neutronic reactor including a reactive core, a re?ector
extending about the core, a movable member or specimen
rack in the reactor for supporting a plurality of specimens
ly low. Certain short-lived radioactive isotopes can be
to be irradiated, means for removing a specimen from the
produced with every little longer-lived contamination so
specimen rack at a predetermined position in the reactor,
that decay to a negligible background takes place within
a day or two. A further advantage is that short-lived 40 and means for moving the specimen within the specimen
rack in the predetermined position. While many different
radioactive wastes are far easier to dispose of than longer
types of reactors may be utilized for purposes of this
lived radioactive wastes.
invention, it is preferred, but not essential, that the re
Accordingly, it would be ‘desirable to have available
actor core be located in a tank which is disposed Within
short-lived radioactive isotopes for commercial uses. This
may be accomplished by producing the particular radioac 45 a pit in the ground, so that effective shielding against
radiation may be afforded in an economical manner, with
tive isotopes in an isotope-producing facility such as a
out resorting to expensive above-the-ground shielding
neutronic reactor on the premises of the utilizing organi
structures. The tank is ?lled with a suitable liquid such
zation.
as water which serves as a moderator, coolant and shield
Additional advantages arise from having a neutronic
reactor on the premises which is capable of producing 50 ing. Cooling means may be provided for the fluid within
the tank for regulating the temperature of the core. Suit
radioactive isotopes. In this connection, regardless of
able pickup means are furnished to remove the specimens
the length of the half lives of the radioactive isotopes pro
from the reactor while it is in operation. Also furnished
duced by the reactor, such radioactive isotopes generally
in the reactor is a control system for regulating the power
would be more readily available than if they had to be
obtained on order from some central organization, such as 55 level of the reactor.
The core of the reactor may be of any suitable con
the Atomic Energy Commission. Furthermore, the uti
struction. However, it is preferable if the core is de
lizing organization would have greater privacy as to the
signed so that the reactor is inherently safe, i.e., it will
nature of its work, and better control of the chemical and
not be damaged by an unexpected and sudden surge in
physical form of the samples which are irradiated. In
addition if a large number of isotopes are made, it may be 60 neutron multiplication. In the illustrated embodiment,
the core of the reactor is designed, in combination with
less expensive to make them in one’s own reactor than to
the remaining components of the reactor, to have a high
buy them. 7‘
prompt negative temperature coe?icient of reactivity, i.e.,
To be a useful isotope-producing reactor which operates
one which does not require the ?ow of heat from one
on the premises of a utilizing organization, the reactor
should be designed to allow continuous or intermittent 65 region to another in order for it to come into play. This
operation with equal case, but capable of being operated
by relatively unskilled operators. It should provide for
simultaneously irradiating a large number of samples of
is responsible for the great safety of the present reactor
during its operation.
Now referring particularly to the drawings, the reactor,
designated by the reference numeral 20, includes a core
able and removable from the reactor while the reactor is 70 21 disposed near the bottom of a reactor tank 22 which
is ?lled with a liquid 23. The core 21 includes a plu
in operation and with minimum handling time. The re
rality of fuel elements 24. Disposed in the core 21 are
actor should have sufficient power so that a wide range
various sizes ‘and shapes. The samples should be insert
3,094,470
3
'4
‘control rod‘ assemblies 25 which?areioperated by suitable
tioned control rod assembliesWZ‘S are provided, one‘ of
which is shown. Each of these control rod assemblies 25
winch mechanism (not shown) located above the reactor
tank 22. ,A re?ector 27, encircles the core 21. ‘Irradia
tion facilities including a movable specimen rack 28 are
includes a control rod which is designed to perform a dif
ferent function in the reactor so as to achieve both range
and accuracy of control. A so~called shim safety rod is
provided in the core 21 and re?ector 727, for irradiating
specimens at preselected radiation levels.’
‘
used for coarse control of the reactor.
Reactor tank 22 is located in a generally cylindrical
pit 30. The pit 30 may be constructed by standard con
The shim safety
rod has a; fairly large reactivity equivalent. A regulat
ing rod having a smaller reactivity equivalent is provided
struction methods, with the hole lined with concrete,’ steel
for ?ne control of the reactivity. ‘The shim safety rod
In the particular assembly 10 and the regulating rod each have a reactivity equivalent
illustrated, the lining 31 of the hole is concrete. The
great enough to shut down the reactor. A third rod hav
depth ofthe reactor tank 22 is controlled by the amount
ing a large reactivity equivalent which may be equal to
of liquid shielding desired above the reactor core 21 which c that of the shim safety rod is used as a safety rod. -It has
is Within the tank 22. The Width, of the reactor tank 22
a large enough reactivity equivalent to shut the reactor
is controlled by the diameter of the reactor core 21, the 15 down and is used to shut down the reactor quickly in the
, or other reinforcing material.
size of the re?ector127 and the shielding required to re
event of ‘an emergency.
duce the neutron activity to a desired value at the bound
ary of the tanlc. ‘ Reactor tank _22_ is preferably con
structed of a materialhaving a low neutron capture cross
‘
V
H
7
While the center of the core 21 may also be provided
with a control rod assembly, in the illustrated embodi
ment a tubular irradiation thimble ‘4.2 is run vertically
section. Since the reactor tank 22, is designed to contain 20 through an enlarged-central hole in the lower grid plate
liquid such as water, aluminum is preferred in order to
of the core, through the central hole of; the upper grid
minimize corrosion problems and to also reduce costs of
plate and through the‘reactor tank 22 to the top’ thereof.
construction. Reactor tank 22 is cylindricalin form with . ‘This thimble or “glory hole” 42'is at a point of
an open top of suitable dimensions to tit inside the, pit _n_eutron ?ux in the reactor. ' The thimble =42 is useful for
30. The bottom of reactor tank 22 is supported in posi 25. isotope production, pile-oscillation experiments, and dan
tion above a horizontally extending concrete base '32
ger-coe?icient experiments._
,,
g _
which forms the bottom of pit 30. The bottom ofv the
The core :21 is centrally located with respect to the re
tank 22 rests on a platform comprising a ?at, generally
?ector 27. > Any material having good scattering proper
circular plate 33 preferably of aluminum. The plate 33
ties and a low neutron absorption cross section, such as
in turn is supported on a ‘series of lhorizon'tal'aluminum
graphite, beryllium or beryllium oxide, can be used to
' beams 29.
A-por‘ous ?ll, s'uchas gravel,‘is" placed in an
construct the re?ector 27 .
annular space 34 between the wall of the reactor tank
In the illustrated embodiment
a plurality of suitably shaped graphite blocks 44 are used.
22 and the Wall of ‘the pit 30. ‘ Any water which may leak
There?ector 27 is substantially cylindrically shaped with
into the‘ annular space 34, either from the reactor tank
a hollow circular center and is completely encased in a
22 or inwardly from the outside of the concrete lining 35 water-tight can 46. , ,
,
. 31,fis collected in a's'pace .35 at the bottom of'the pit 30.
The [diameter of the reactor tank 22 is made substan
.A suction line (not shownl'm'ay. be run downthrough
tially larger than the outer diameter of the re?ector 27 ‘ to
the annular space 34 to remove any water which'may
provide an annular space between the reactor tank 22 and
collect.
_.
v
,
.
.
the re?ector 27.
.
This space, when ?lled with water, in
Reactor tank 22 is' .disposed" within the ground in'the 40 creases'the neutron ?ux available in the re?ector :27,
described manner so‘ that the ground itself acts as' a
While using the minimum possible size re?ector ‘27, In
natural protective shielding m'eans'fo-r the‘ reactor. Ac
addition, this annular space facilitates the installation and
cordihgly, construction costs are reduced, since expensive
. removal of the re?ector assembly 27.
' above-the-ground shielding structures are obviated.
The graphite
blocks 44 are encased in the water-tight can 46 so as to
A horizontal shelf. 36 is preferably provided at‘the 45 prevent Water, from entering the re?ector material and
upper .end of the pit 30Ifor themounting of the control
decreasing the reactivity of the reactor.
rod winch'm'echan'ism. The outeriperimeter' of'the shelf
Referring to ‘FIGURES l, 2 and 3, the rotary specimen
36 is illustrated. asbeing substantially ‘square, however,
rack 28, which is located in an annular recess 48 in ‘the
the Tspec'i?c contour of ‘the perimeter of the shelf is un
re?ector 127, is constructed so that specimens can be
important. The surface of the ‘shelf 36'i's at a su?icient 50 loaded and unloaded conveniently during operation, and
[depth from floor level 37 to accommodate the height‘ of
so that such specimens are uniformly irradiated. The
‘ the winch mechanisms. A channel 38 may be attached
rotary specimen rack '28 includes a plurality of spaced
‘to the concrete at each edge .of the perimeter ‘of the'shelf
cups 150 which are attached to and extend below a flat,
...35'for support of a two seems cover 40 over the pit’ 30‘.
horizontally extending, rotatable ring 52. The cups 5%
. If‘desired, a grate may be' used for the cover ‘40 so that 55 serve as holders for specimen containers. .In the illus
the , reactor can be visually observed during ‘operation.
trated embodiment, the cups 50 are each in the form of
Within the lower portion of reactor tank‘ 22'is located
a cylindrical tube closed at its lower end. The cups are
the core 21 which‘ is in the general form of a right circular
attached so as to extend downwardly from a series of
‘cylinder and oomprisesqa lattice ‘of generally vertically
spaced holes 54 in the ring 52. The number of cu-ps' 50
extending ‘fuel elements‘ 24 held in spaced relation by
' grid plates or-the like.
is dependent upon the requirements ‘of theinstallation.
I
l, the fuel ‘elements \24 in the
In the illustrated embodiment, forty cups are disposed at
equal intervals around the ring 52. The upper surface
core‘ zl'extend in a generally vertical direction and are
of the ring is countersunk at each hole 54 so as to guide
As; seen in
generally uniformlyspaced in concentric circles. T The
lillustratedreactor‘ provides‘po‘sitions for eighty-six fuel
elements 124.‘ ’The unused positions are occupied by
dummy‘ elements whichjare generally similar‘in outer eon
’s'tru'ction to ‘the fuel elements 24. The‘ dummy elements
65
the specimen containers into the cups 50.
The ring 52 and cups are, rotatably supported within a
housing ‘56 by a bearing structure 58. Any bearing struc
ture which allows the ring 5-2 to be freelyrotatable rela
tive' to the housing 56 may be ‘used. ‘In the illustrated
are essentially completely ?lled with a suitable re?ecting
embodiment, a ball bearing ring structure'is' used. The
material‘ such as graphite. t'It’sh'ould be understood that 70 ball bearing ring structure includesjan inner ‘race 60, an
p the number of fuel elements 24 as comparedto the'rdummy
outer race 62, and a plurality of balls64 rotatably engaged
elements will vary considerably, ‘depending’ upon ‘the gen
therein. The outer ‘race 62 is fastened securely to a mat
' eral design‘ and-dimensions of the reactor‘and particular
ing recess 66 at the lower inner corner“ of the ring 52.
arrangement of the'fuel'elements' 24.
The inner race 60 is fastened to a mating recess 68 Within
In the illustrated embodiment, three symmetrically posi 75 a bearing support ring 70, which in turn is securely at
3,094,470
tached to the housing 56, preferably by welding. The
ring 52 is rotatable from the top of the reactor to con
tinuously move the cups ‘50 around the reactor core, and
also to successively bring each cup 50‘ to a position under
a single vertically extending delivery and removal pipe 72.
The housing "56, previously mentioned, is of water
tight construction and encloses the internal mechanism
‘of the specimen rack 28. The housing 56 is designed so
shaft extends through the pipe 92 to the top of. the re
actor. Preferably, the positioning shaft 90 is in more
than one section for ease of assembly. The upper end
of the positioning shaft extends through the ‘bearing plates
108 and 110.
A suitable gripping means, such as a
handle 116 is attached to the upper end of the positioning
shaft 90.
The positioning shaft 90 includes a pair of vertically
spaced, horizontally extending pins 118 and 120 located
as to substantially occupy the annular recess 48, and thus
minimize the introduction of water into the re?ector vol 10 adjacent its upper end which coact with the bearing
plates 108 and 1110 to prevent excessive withdrawal of
ume. The housing ‘56 may be removed from the reactor
the positioning shaft and to maintain the positioning shaft
tank 22 without disturbing the core 21 or re?ector 27.
out of engagement with the holes 114 during the period
In the illustrated embodiment, the housing 56 is
that the specimen rack 28 is rotated. The lower pin
formed by welding or the like and includes a stepped tubu
lar inner wall 74, a tubular outer wall 76, a ring-shaped 15 118 is positioned below the lower bearing plate 108 a dis
tance such that when the lower end of the positioning
bottom wall 78, and a ring-shaped top wall 80. The top
shaft 90 is raised above the surface of the ring 52 to
and bottom portions of the inner wall Mare of different
" permit the specimen rack 28 to'rotate, the lower pin
diameters. The top portion which is ‘of smaller diameter
118 will abut against the lower surface of the lower bear
is connected to the bottom portion by a ring 80a which
forms a shoulder which rests .on the re?ector 27 when ‘the 20 ing plate 108. The upper pin ‘120 is so located on the
positioning shaft 90' as to just clear a suitably slotted
housing 56 is properly positioned in the reactor. Lifting
hole 122 in the upper bearing plate 110 before the po
lugs 82 are attached to the upper portion of the inner wall
sitioning shaft 90 is stopped by the lower pin. To lock
74 .of the housing '56 to facilitate the handling of the ro~
t-a'ry specimen rack 28.
the positioning shaft in its uppermost position, the po
extends across and is fastened to the inside of the hous
bearing plates 110 and 108. The indicating pointer 126
used to secure the chain 104 to the ring 52, such as
relationship and ‘for enclosing the bearing plates 108 and
A pair of openings \84 and 86 are provided in the top 25 sitioning shaft is rotated until the upper pin 120 is no
longer in alignment with the slot 1122 after which the
wall 80 for the delivery or removal of specimen con
positioning shaft 90 is released. The positioning shaft
tainers and for enclosing a drive shaft and a positioning
will
be maintained in its raised position by the engagement
shaft 88 and 90 respectively (described subsequently).
of the upper pin 120 with the upper bearing plate 110.
In the illustrated reactor the openings 84 and 86 :are dia
If desired, a biasing spring (not shown) may be pro
metrically opposite to each other. Vertically extending 30
vided to urge the positioning shaft 90 in a downward
tubes or pipes 72 and 92 which connect with the openings
direction so as to prevent accidental release of the po
84 and ‘86 extend from the top of the housing 56 to the
sitioning shaft when it is in engagement with one of the
top of the reactor tank 22. The pipes 72 and 92 are
holes 114.
preferably formed in mating sections for ease of assembly.
To indicate the position of the ring 52, the drive shaft
The delivery and removal pipe 72 is slightly larger in 35
88
is connected through a suitable gear train 124 to an
diameter than that of the cups 50. The lower end of
indicating pointer 126. The gear train includes a pinion
the delivery and removal pipe 72 extends into the hous
gear 128 attached to the upper end of the drive shaft
ing 56 and is attached therein to a suitable supporting
88, a pair of idler gears 130 and 132 which are attached
member 94.
The pipe 92 which encloses the drive shaft 88- and the 40 to an idler shaft 134 and a spur gear 136 attached to
an indicator shaft 138 on which the pointer 126 is mount
positioning shaft 90 is of larger diameter than that of the
ed. The idler shaft 134 and the indicator shaft 138 are
delivery and removal pipe 72. A bearing plate 96 for
journaled in suitable bearings (not shown) located in the
supporting a sprocket 98 ‘and the positioning shaft ‘90
is arranged to move across an indicating dial 140 as the
ing 56 at the lower end of the pipe 92. The bearing plate
96 contains two vertically supported bushings i100 and 45 drive shaft 88 rotates the ring 52. The indicating dial
‘140 is suitably calibrated so as to indicate the positions
1192 for the positioning shaft 90, and for the drive shaft
of the ring 52 where the cups 50 are in alignment with
88, respectively.
the delivery ‘and removal pipe 72.
A roller chain 1414 and sprocket 98 are used to rotate
A housing 142 which is suitably supported above the
the ring 52 and cups 511. The chain 104 extends along
reactor
tank 22 on the channels 38 is provided for sup
the upper surface of the ring 52 and is fastened at spaced
porting the bearing plates 108 and 110 in spaced apart
intervals thereto. Any suitable fastening means can be
110, and the gear train 124.
Thus it is seen that means are provided for manually
The sprocket 98 is fastened to the lower end of the
drive shaft v8% beneath the bearing plate 96. The sprocket 55 indexing the cups 50 with respect to the delivery and
removal pipe 72 for exchange of samples in the reactor.
93 engages and drives the roller chain ‘104. Thus, the
‘In order to assure uniform irradiation of the samples
rotation of the drive shaft 88 causes a correlative rota
when in the reactor, there is also provided means for
tion of the ring 52. A collar 106 is attached to the
continuously rotating the sample supporting ring 52 at
drive shaft 88 above the bushing 102 to maintain the
a uniform, predetermined speed within the reactor. More
sprocket 98 in vertical alignment with the roller chain
particularly, there is provided a powered driving means
104. The drive shaft 88 extends upwardly through the
which is suitably connected to the ring drive shaft 88 for
pipe 92 to the top of the reactor tank 22. As seen in
effecting selective, continuous rotation of the ring 52 and
FIGURE 4, the upper end of the drive shaft 88 extends
the cups 50 supported thereby.
through a pair of vertically spaced bearing plates 108
An electrical motor 144 is suitably mounted within the
and 114i. Attached to the upper end of the drive shaft 65
housing 142, and this motor has a drive shaft 146 ?xedly
88 is a turning means, such as a hand wheel 112.
mounting a pinion gear 148 which is in meshing engage
A positioning hole 114 is drilled in the ring 52 ad
ment with the gear train 124 through the idler gear 130.
jacent each cup 561 to insure proper positioning of the
‘Preferably, the motor drive shaft 146 includes a slip
cups relative to the delivery and removal pipe 72. The
holes 114 are so located that whenever the positioning 70 clutch 149, or the like, ‘to permit rotation of gear 148
when the motor is turned off and ‘manual control handle
shaft 94} drops into a hole 114 one of the cups 50 is in
112 is used. An off-on switch control, indicated at 151,
alignment with the delivery and removal pipe 72. The
is provided for the 'motor 144 and this switch is located
holes 114- are located on the upper surface of the ring
on the upper surface of the housing 142. Consequently,
52 and are of a diameter such that the positioning shaft
90 may be slidably engaged therein. The positioning 75 once the desired number of samples are placed in the cups
riveting.
-
3,094,470
,.
50, which are individually indexed with respect to the
delivery pipe 72 through manual rotation of ring 52 by
8
.
3. Apparatus-for irradiating a plurality of specimens
uniformly in a neutronic reactor having a reactive core,
said apparatus comprising a supporting member for sup
porting a plurality of spaced apart specimens to be irradi
operation of the manual control 112, the motor 144» can
‘be operated to thereby provide continuous rotation of
the samples about the reactor core at a selected, uniform
rate of speed. This rotation of the samples is of con
ated about the periphery of the core, said supporting
member being continuously movable completely around
the core, a selectively operable motor means for operating
siderable advantage in effecting uniform irradiation of
the samples, since the samples are thereby exposed equal
unidirecti-onally at a selected uniform speed, connecting
ly to all sides of the reactor core wherein there is ordi
means between said supporting member ‘and said motor
narily some variation in the radiation intensity with re
spect to the several surfaces of the core.
10 means ‘for continuously driving the specimens-on said
supporting means completely around the core and expos
If desired, suitable clutch mechanism (not shown) may
ing the specimens substantially equally to all sides of ‘the
be interposed between handle 112 and drive shaft $8 to
core during each revolution ‘about the core, ‘and indexing
means coupled to said supporting member for indicating
the position of the specimens within the reactor as the
specimens are moved therearound by said motor means.
selectively disengage the handle and prevent its rotation
during motor operation of the drive shaft.
To prevent moisture ‘from accumulating within the
housing 56, one or more of the cups 50 may be provided
4. Apparatus'for irradiating a plurality of specimens
with suitable perforations or openings 15%} and these cups
may be loaded from time to time with removable charges
uniformly in a neutronic reactor having a reactive core
of a suitable drying agent such as silica gel.
In one em
and a re?ector extending about the core, said apparatus
20 comprising walls de?ning a recess in the re?ector which
extends in a circular direction, a ?at ring supported ad
bodiment, for example, four spaced cups were suitably
perforated, each with approximately ‘forty 1%; inch diam
erter holes.
jacent the mouth of said recess, said ring being continu
ously movable completely around the core, a plurality
‘of horizontally spaced-apart cups connected to and ex
tending downwardly from said ring into said recess for
In addition, one of the cups included a cen
tral % inch hole in its ‘bottom wall to permit a sponge
or other absorbent material to be lowered therethrough
holding ‘a plurality of specimens to be irradiated, a selec
into contact with the bottom wall of the housing 56 to
tively operable motor means for operating unidirection
test ‘for the amount of moisture within the housing.
ially at a selected uniform speed, connecting means be
In order to determine the positions of the perforated
tween said supporting member and said motor means for
cups, the positioning hole 114 associated with one of the
perforated cups is somewhat deeper than the rest of the 30 continuously driving the specimens on said ring complete
ly around the core and exposing the specimens substan
positioning holes, so that when the positioning'shaft 90
tially equally to all sides of the core during each revolu
drops to a lowermost position, it denotes that its perfo
tion about the core, and indexing means coupled to said
rated cup is in line with the delivery and removal pipe
ring for indicating the position of said cups within ‘the
72. Preferably, the indicating mechanism is adjusted so
that at the position where the positioning shaft 5N) is in 35 reactor as the specimens are moved therearound by said
motor means.
line with the deeper positioning hole 114, the pointers
126 will point to the dial 140 at some de?nite marking,
5. Apparatus for irradiating a plurality of specimens
for example, position number 1. Knowing the .relative
uniformly in a neutronic reactor having a reactive core
and are?ector extending about the core, said apparatus
rotate the specimen rack to position any desired per-fo 40 comprising walls de?ning ‘a recess in the re?ector which
extends in a circular direction, a ?at ring supported ad
rated cup under the delivery and rem-oval pipe 72 by ref
jacent the mouth of said recess, said ring being co-ntinu—
erence to the position of the indicating pointer 126 and
ously movable completely around the 'core, a plurality of
dial 140.
.
horizontally spaced-apart cups connected to and extend
Although shown and described with respect to par
ing downwardly from said ring into said recess for hold
ticular mechanism, it will be apparent that various modi?
ing a plurality of specimens to be irradiated, drive means
cations might be made without departing from the prin
extending from the exterior of the reactor to said recess,
ciples of this invention.
said drive means including a selectively operable motor
We claim:
~
means and means connecting said motor means in driv
1. A method of irradiating a plurality of specimens
ing relation with said ring for effecting continuous rota
in an isotope-producing neutronic reactor, comprising
tion of said ring unidirectionally eat a selected uniform
loading the specimenson a supporting member in spaced
speed completely around the core and exposing the speci
‘apart relation peripherally of the core of the reactor,
mens substantially equally to all sides of the core during
continuously moving the supporting member completely
around the core at a selected, uniform speed to expose 55 each revolution about the core, and means for selectively
positioning said ring so as to ‘locate any selected cup at
each specimen substantially equally to all sides of the
a predetermined position, said positioning means includ—
core during each ‘revolution about the core, providing
ing an indicator which is connected to said drive means
indicator means for indicating the positions of the speci
for indicating the position of the cups relative to said
mens as the specimens are rotated about the core, and
positions of the other perforated cups, one can readily
predetermined position.
selectively removing said specimens from the supporting
member.
6. Apparatus for irradiating a plurality of specimens
'
uniformly in a neutronic reactor having a reactive core
2. A method of irradiating a plurality of specimens in
an isotope-producing neutronic reactor, comprising load
ing the specimens on a supporting member in spaced
apart relation peripherally of'the core of the reactor, con
tinuously moving the supporting member completely
around the core at a selected, uniform speed to‘ expose
65
and a re?ector extending about the core, said ‘apparatus
comprising Walls de?ning a recess in the re?ector which
extends in a circular direction, a ?a-t ring supported ad~
jacent the mouth of said recess, said ring being continu
ously movable completely around the core, a plurality
of horizontally spaced-apart ‘cups connected to and ex
each specimen substantially equally to all sides of the
tending downwardly from said ring into said recess for
core during each revolution about the core, providing
holding a plurality of specimens to be irradiated, drive
indicator means which is responsive to the position of the 70 means extending from the exterior of the reactor to said
supporting member to indicate the positions of the speci
recess, said drive means including a selectively operable
mens around the core and with respect to a position for
motor means and means connecting ‘said motor means in
loading and unloading the specimens on the supporting
driving relation with said ring for effecting continuous
member, and selectively placing said specimens at the un
rotation of said ring unidirectionally at a selected uniform
loading position for removal from the core.
75 speed completely around the core and exposing the speci
3,094,470
10
mens substantially equally to all sides ‘of the core during
each revolution about the core, and means for removing
a specimen from ‘a cup ‘at a predetermined position in
said recess, manually operable means connected with
said drive means for selectively positioning said ring so
as to locate any selected cup at a predetermined position,
said positioning means including an indicator which is
connected to said drive means for indicating the position
of the cups relative to said predetermined position, and
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,793,970
2,858,442
2,874,108
2,914,450
Jeppson ______________ __ May 28,
Dewey ______________ __ Oct. 28,
Ohlinger et ‘a1. _______ __ Feb. 17,
Hammesfahr et a1 _____ __ Nov. 24,
1957
1958
1959
1959
OTHER REFERENCES
Proceedings of the Second United Nations Interna
a releasable locking means for said ring Which is engage 10 tional Conference on the Peaceful Uses of Atomic
ahle therewith only when 1a cup is at said predetermined
Energy, vol. 10, United Nations, Geneva, 1958, pages
position for preventing the rotation of said ring.
282-286.
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