PLUG DEMOUNTING APPARATUS FOR HEAVY WATER REACTOR FUEL SYSTEM

DISPOSITIF DE DEPOSE DU BOUCHON POUR SYSTEME DE COMBUSTIBLE DE REACTEUR A EAU LOURDE

English Abstract

Provided is a plug dismounting apparatus for a heavy water reactor fuel
system. The plug
dismounting apparatus for dismounting a plug (10) that is mounted on a fuel
element in a heavy
water reactor fuel system, and includes a locking rim (11) formed along an
inner circumference
thereof and a push pipe (12), includes: a clamp housing (100) made up of an
outer housing (110)
having a plurality of ball holes (111) formed in a radial direction and
inserted into an inner
diametrical region of the plug (10) and an inner housing (120) having a stem
bush (121); locking
balls (200) coupled to the ball holes (111) of the outer housing (110), and
locked on the locking
rim (11) so as to fix the clamp housing (100) to the plug (10); a guide liner
(300) having a release
groove (310) formed so as to guide release of the locking balls (200), and
coupled so as to guide
sliding of the inner and outer housings (120 and 110); elastic members (400)
interposed between
the guide liner (300) and the clamp housing (100), and restoring the released
locking balls (200) so
as to be elastically locked; a latch ram (500) coupled so as to slide into an
inner diametrical region
of the inner housing (120), and pressurizing an inner surface of the plug
(10); a hollow main stem
(600) screwed to the stem bush (121) of the inner housing (120) so as to slide
the latch ram (500);
and a sub-stem (700) coupled to an inner diametrical region of the main stem
(600) and
pressurizing the push pipe (12) so as to dismount the plug (10).

French Abstract

Un dispositif de dégagement de bouchon pour système de combustible de réacteur à eau lourde est présenté. Le dispositif de dégagement de bouchon sert à dégager un bouchon (10), qui est installé sur un élément de combustible dans un système de combustible de réacteur à eau lourde et qui comprend un rebord de blocage (11) formé le long de sa circonférence intérieure et un tuyau-poussoir (12), comporte : un logement de pince (100) fait d'un logement externe (110) comportant une pluralité de trous de balle (111) formée dans une direction radiale et insérée dans une région diamétrale intérieure du bouchon (10) et un logement interne (120) comportant une garniture de tige (121); les balles de blocage (200) sont couplées aux trous de balle (111) du logement externe (100) et sont bloquées sur le rebord de blocage (11) de sorte à fixer le logement de pince (100) au bouchon (10); une doublure guide (300) comportant une rainure de dégagement (310) est formée de manière à guider la libération des balles de blocage (200) et couplée de sorte à guider le coulissement des logements interne et externe (120 et 110); des éléments élastiques (400) sont interposés entre la doublure guide (300) et le logement de pince (100) et servent à rétablir les balles de blocage (200) libérées pour qu'elles soient bloquées de manière élastique; un bélier de loquet (500) est couplé de sorte à coulisser dans une région diamétrale interne du logement interne (120) et faire pression sur une surface intérieure du bouchon (10); une tige principale creuse (600) est vissée à la garniture de tige (121) du logement interne (120) de sorte à faire coulisser le bélier de loquet (500) et la sous-tige (700) est couplée à une région diamétrale interne de la tige principale (600) et fait pression sur le tuyau-poussoir (12) de sorte à dégager le bouchon (10).

Claims

WHAT IS CLAIMED IS:
1. A plug dismounting apparatus for a heavy water reactor fuel system which
is used
to dismount a plug that is mounted on a fuel element in the heavy water
reactor fuel system and has
a locking rim formed along an inner circumference thereof and a push pipe, the
plug dismounting
apparatus comprising:
a clamp housing made up of an outer housing having a plurality of ball holes
formed in a
radial direction and inserted into an inner diametrical region of the plug and
an inner housing
having a stem bush;
locking balls coupled to the ball holes of the outer housing, and locked on
the locking rim
so as to fix the clamp housing to the plug;
a guide liner having a release groove formed so as to guide release of the
locking balls, and
coupled so as to guide sliding of the inner and outer housings;
elastic members interposed between the guide liner and the clamp housing, and
restoring
the released locking balls so as to be elastically locked;
a latch ram coupled so as to slide into an inner diametrical region of the
inner housing, and
pressurizing an inner surface of the plug;
a hollow main stem screwed to the stem bush of the inner housing so as to
slide the latch
ram; and
a sub-stem coupled to an inner diametrical region of the main stem and
pressurizing the
push pipe so as to dismount the plug.
2. The plug dismounting apparatus according to claim 1, wherein the sub-
stem
includes a first bearing mounted on one end thereof, and the first bearing
rotatably supports the
sub-stem that is rotated to pressurize the push pipe.

3. The plug dismounting apparatus according to claim 1, wherein the sub-
stem
includes a tap hole bored in one end thereof so as to adjust a pressurization
distance on the plug.
4. The plug dismounting apparatus according to claim 1, wherein the outer
housing
includes housing handles that slide the clamp housing along the guide liner.
5. The plug dismounting apparatus according to claim 1, wherein the guide
liner
includes a push lever that slides the guide liner along the clamp housing.
6. The plug dismounting apparatus according to claim 1, wherein the main
stem
includes a stem handle.
7. The plug dismounting apparatus according to claim 1, wherein the sub-
stem
includes a plurality of handlebars in a radial direction.
11

Description

CA 02723210 2013-08-26
PLUG DISMOUNTING APPARATUS FOR HEAVY WATER REACTOR FUEL SYSTEM
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates, in general, to a plug dismounting apparatus for
a heavy
water reactor fuel system, and more particularly to a plug dismounting
apparatus for a heavy water
reactor fuel system, capable of dismounting a plug mounted on a fuel element
in the heavy water
reactor fuel system with ease, rapidity, and precision
Description of the Prior Art
As is well known in the art, a heavy water reactor is a type of nuclear
reactor that uses
heavy water as a coolant and a moderator. The heavy water reactor is equipped
with a fuel system
where plugs are mounted on each fuel element.
The plug is dismounted from the fuel element for various purposes.
Conventionally, a
lug-type fixing apparatus has been fixed to dismount the plug, and then the
plug has been
dismounted or mounted by tightening a handle using nuts.
Such a lug-type fixing apparatus has the following problems.
First, since the lug-type fixing apparatus is fixed using nuts when the plug
is dismounted
and then the handle is tightened, much time is required, and thus there is a
problem with radiation
exposure.
Further, the lug-type fixing apparatus has a problem in that it must be
positioned by
rotating the lug at an angle of 90 when the plug is mounted and dismounted.
Particularly, when it is difficult to dismount the plug because of the close
contact with the
fuel element, the lug-type fixing apparatus must be removed along with the
plug while undergoing
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a strong shock. As such, equipment is easily damaged.
Furthermore, for application to various plugs, a spool is inserted into the
lug-type fixing
apparatus when used, and then is put into a hole for storage using taping. As
such, the spool may
be lost.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made keeping in mind the above
problems
occurring in the prior art, and an object of the present invention is to
provide a plug dismounting
apparatus for a heavy water reactor fuel system, capable of easily and rapidly
dismounting and
Jo mounting a plug, which is mounted on a fuel element in the heavy water
reactor fuel system, to
minimize damage from radiation exposure, and easily dismounting the plug to
maximize the
convenience of use.
Another object of the present invention is to provide a plug dismounting
apparatus for a
heavy water reactor fuel system, capable of simply and easily dismounting a
plug, which is in close
contact with a fuel element in a heavy water reactor fuel system, to
previously prevent damage
caused by a shock as in the related art.
In order to achieve the above objects, according to one aspect of the present
invention,
there is provided a plug dismounting apparatus for a heavy water reactor fuel
system which is used
to dismount a plug mounted on a fuel element in the heavy water reactor fuel
system and has a
locking rim formed along an inner circumference thereof and a push pipe. The
plug dismounting
apparatus includes: a clamp housing made up of an outer housing having a
plurality of ball holes
formed in a radial direction and inserted into an inner diametrical region of
the plug and an inner
housing having a stem bush; locking balls coupled to the ball holes of the
outer housing and locked
on the locking rim so as to fix the clamp housing to the plug; a guide liner
having a release groove
formed so as to guide release of the locking balls and coupled so as to guide
sliding of the inner
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=
and outer housings; elastic members interposed between the guide liner and the
clamp housing and
restoring the released locking balls so as to be elastically locked; a latch
ram coupled so as to slide
into an inner diametrical region of the inner housing and pressurizing an
inner surface of the plug; a
hollow main stem screwed to the stem bush of the inner housing so as to slide
the latch ram; and a
sub-stem coupled to an inner diametrical region of the main stem and
pressurizing the push pipe so
as to dismount the plug.
In exemplary embodiments, the sub-stem may include a first bearing mounted on
one end
thereof, and the first bearing may rotatably support the sub-stem that is
rotated to pressurize the
push pipe.
In exemplary embodiments, the sub-stem may include a tap hole bored in one end
thereof
so as to adjust a pressurization distance on the plug having a different
shape.
In exemplary embodiments, the outer housing may include housing handles that
slide the
clamp housing along the guide liner.
In exemplary embodiments, the guide liner may include a push lever that slides
the guide
is liner along the clamp housing.
In exemplary embodiments, the main stem may include a stem handle, and the sub-
stem
may include a plurality of handlebars in a radial direction.
According to the present invention realized by the aforementioned means, since
the clamp
housing slides along the guide liner and is elastically locked on the locking
rim of the plug, it is
easy to mount and dismount the clamp housing, and thus the plug mounted on the
fuel element in
the heavy water reactor fuel system is rapidly dismounted and mounted to be
able to minimize
damage from radiation exposure.
Further, the present invention can previously prevent damage caused by a shock
as in the
related art by simply and easily dismounting the plug, which is into close
contact with the fuel
element, using the sub-stem.
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BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present invention
will be more
clearly understood from the following detailed description when taken in
conjunction with the
accompanying drawings, in which:
FIG. 1 is an assembled perspective view illustrating an embodiment of the
present
invention;
FIG. 2 is a disassembled perspective view illustrating an embodiment of the
present
invention;
0 FIG. 3 is a cross-sectional view illustrating an embodiment of the
present invention;
FIGS. 4 through 6 illustrate a process of mounting a clamp housing on a plug
according an
embodiment of the present invention; and
FIGS. 7 through 9 illustrate a process of dismounting a plug using a latch
ram, a main
stem, and a sub-stem according an embodiment of the present invention.
<Description of symbols of the main parts in the drawings>
10: plug 11: locking rim
12: push pipe 13: jaw
14: inner surface 100: clamping housing
110: outer housing 111: ball hole
112: mounting groove 113: housing handle
114: handle bracket 120: inner housing
121: stem bush 122, 640: female thread
200: locking ball 300: guide liner
310: release groove 320: operation long slot
330: push lever 400: elastic member
4
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500: latch ram 600: main stem
610, 710: male thread 620: second bearing
630: stem handle 700: sub-stem
720: first bearing 730: handlebar
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in greater detail to exemplary embodiments of the
invention
with reference to the accompanying drawings. Wherever possible, the same
reference numerals
will be used throughout the drawings and the description to refer to the same
or like parts.
As illustrated in FIGS. 1 through 3, the present invention provides a plug
dismounting
apparatus for a heavy water reactor fuel system which is used to dismount a
plug 10 mounted on a
fuel element in the heavy water reactor fuel system and has a locking rim 11
formed along an inner
circumference thereof and a push pipe 12. The plug dismounting apparatus
includes: a clamp
housing 100 made up of an outer housing 110 having a plurality of ball holes 1
l 1 formed in a
radial direction and inserted into an inner diametrical region of the plug 10
and an inner housing
120 having a stem bush 121; locking balls 200 coupled to the ball holes 111 of
the outer housing
110 and locked on the locking rim 11 so as to fix the clamp housing 100 to the
plug 10; a guide
liner 300 having a release groove 310 formed so as to guide release of the
locking balls 200 and
coupled so as to guide sliding of the inner and outer housings 120 and 110;
elastic members 400
interposed between the guide liner 300 and the clamp housing 100 and restoring
the released
locking balls 200 so as to be elastically locked; a latch ram 500 coupled so
as to slide into an inner
diametrical region of the inner housing 120 and pressurizing an inner surface
of the plug 10; a
hollow main stem 600 screwed to the stem bush 121 of the inner housing 120 so
as to slide the
latch ram 500; and a sub-stem 700 coupled to an inner diametrical region of
the main stem 600 and
pressurizing the push pipe 12 so as to dismount the plug 10.
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The clamp housing 100 is generally divided into the outer housing 110 and the
inner
housing 120, both of which are formed in a cylindrical shape. The inner
housing 120 is inserted
into the outer housing 110. Here, the outer and inner housings 110 and 120 are
connected by
connection pins 130 with an appropriate gap formed between an inner surface of
the outer housing
110 and an outer surface of the inner housing 120.
The plurality of ball holes 111 are radially bored in one end of the outer
housing 110, and
are coupled with locking balls 200. Each ball hole 111 is designed such that
its inner diameter is
reduced in a radial outward direction, thereby keeping the coupled locking
ball 200 from escaping
in the radial outward direction. Further, the outer housing 110 is provided
with mounting grooves
to 112 in the other end thereof in which the elastic members 400 are
mounted, thereby preventing
arbitrary movement of the elastic members 400. It should be noted that the
mounting groove 112
may be formed in various shapes depending on how the elastic member 400 is
realized. For
example, if each elastic member 400 is realized as a coil spring, the mounting
grooves 112 are
formed in the other end of the outer housing 110 at proper intervals such that
a plurality of coil
springs are mounted. Further, the outer housing 110 is provided with housing
handles 113 on an
outer surface of the other end thereof so as to be opposite to each other in a
diametrical direction,
thereby sliding the outer housing 110, and the resulting clamp housing 100. To
this end, the outer
housing 110 is provided with handle brackets 114 on the outer surface of the
other end thereof so
as to be opposite to each other in a diametrical direction, thereby firmly
fixing the housing handles
113.
The stem bush 121 is provided on one side of the inner housing 120, and is
provided with
female threads 122 in an inner circumferential surface thereof.
The guide liner 300 guides sliding of the clamp housing 100 made up of the
inner and
outer housings 120 and 110. The guide liner 300 is provided with a release
groove 310 in an outer
circumference of one end thereof, thereby releasing the locking balls 200.
Further, the guide liner
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300 is provided with operation long slots 320 so as to guide sliding of the
connection pins 130
connecting the inner and outer housings 120 and 110. In addition, the guide
liner 300 is provided
with a push lever 330 on the other end thereof, so that it can slide along the
clamp housing 100.
The elastic members 400 are interposed between the guide liner 300 and the
clamp
housing 100, and elastically restore the locking balls 200 located in the
release groove 310. As
illustrated in FIGS. 1 and 2, each elastic member 400 may be realized as a
coil spring having a
compressive force. However, it should be noted that each elastic member 400
may be realized as,
for instance, a leaf spring having a compressive force if necessary.
As illustrated in FIG. 1, the latch ram 500 is formed in a cylindrical shape,
and is slidably
coupled into an inner diametrical region of the inner housing 120. Thereby,
one end of the latch
ram 500 pressurizes an inner surface 14 of the plug 10. Thus, the clamp
housing 100 of the present
invention is firmly fixed to the plug 10 by the locking balls 200 and the
latch ram 500.
The main stem 600 has a hollow structure, and linearly slides the latch ram
500 along an
axial direction of the inner housing 120. The main stem 600 is provided with
male threads 610 on
an outer circumferential surface thereof, and thus is screwed to the female
threads 122 formed on
the stem bush 121 of the inner housing 120. The main stem 600 is provided with
a second bearing
620 at one end thereof, and is connected to the latch ram 500. Thus, when
rotated in one direction,
the main stem 600 slides the latch mm 500 relative to the screwed inner
housing 120 in a forward
or backward direction. The main stem 600 is provided with a stem handle 630 at
the other end
thereof, thereby facilitating the rotation of the main stem 600. Further, the
main stem 600 is
provided with female threads 640 in an inner circumferential surface thereof.
The sub-stem 700 is screwed into the main stem 600, and pressurizes the push
pipe 12 of
the plug 10. The sub-stem 700 is provided with male threads 710 on an outer
circumferential
surface of one end thereof, and thus is screwed to the female threads 640 of
the main stem 600.
The sub-stem 700 is provided with a first bearing 720 at one end thereof,
thereby promoting
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smooth rotation of the sub-stem 700 pressurizing the push pipe 12. A plurality
of handlebars 730
are installed on the other end of the sub-stem 700, so that it is possible to
apply greater external
force when the push pipe 12 is pressurized.
Overall operation of the present invention constructed in this way will be
described below
in detail with reference to the attached drawings.
First, as in FIG. 4, to mount the present invention on the plug 10, the clamp
housing 100
gets close to an outer end of the plug 10. In this state, when the housing
handles 113 are pulled, the
elastic members 400, i.e. the coil springs, are contracted, and thus the outer
housing 110 slides
along the guide liner 300 in a backward direction. Thereby, the locking balls
200 are put in the
i 0 release
groove 310 of the guide liner 300 as in FIG. 5. As a result, the outer housing
110 is inserted
into the inner diametrical region of the plug 10 as in FIG. 5.
Subsequently, when the outer housing 110 is pulled in a forward direction, the
locking
balls 200 are caught on an inner side of the locking rim 11, and thus are
fixed to the plug 10 as in
FIG. 6.
Then, when the stem handle 630 is turned in an arrow direction shown in FIG.
7, the main
stem 600 is rotated to slide the latch ram 500 in a forward direction as in
FIG. 7. In FIG. 7, the
latch ram 600 is not in contact with the inner surface 14 of the plug 10.
However, when the stem
handle 630 is continuously turned, the latch ram 600 comes into contact with
the inner surface 14
of the plug 10.
Next, when the handlebars 730 are turned in an arrow direction shown in FIG.
8, the sub-
stem 700 is rotated to pressurize the push pipe 12, so that the plug 10 fixed
to a fuel element by a
jaw 13 as in FIG. 8 can be dismounted.
As described above, the process of dismounting the present invention fixed to
the plug 10
proceeds in a reverse order of the description above, and thus description
thereof will be omitted.
The present invention has been described with reference to the exemplary
embodiment
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disclosed above. The scope of the claims should not be limited by the
preferred embodiments set
forth in the examples, but should be given the broadest interpretation
consistent with the
description as a whole.
9
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Representative Drawing