Induced nuclear reactions: processes – systems – and elements – With control of reactor – By movement of control element or by release of neutron...
Reexamination Certificate
2000-01-27
2001-12-25
Carone, Michael J. (Department: 3641)
Induced nuclear reactions: processes, systems, and elements
With control of reactor
By movement of control element or by release of neutron...
C376S327000, C376S229000, C376S230000, C376S228000
Reexamination Certificate
active
06333955
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a control rod and more particularly to a control rod suitable for use in a boiling water type nuclear reactor.
A boiling water type nuclear reactor uses a control rod for reaction degree control of the reactor center. The control rod is composed of four blades of a neutron absorption material covered with a U-shaped stainless steel sheath which are arranged crosswise as shown in FIG. 5 of Japanese Patent Application Laid-Open 61-95277. The control rod is connected to the control rod derive unit and inserted into the reactor center by the drive operation of the control rod drive unit or pulled out from the reactor center.
The connection of the control rod to the control rode drive unit is executed as shown below. The pull-up handle provided on the control rod is pulled up, and the lock plug extended into the coupling socket provided at the lower end of the control rod is pulled up, and the coupling spud of the control rod drive unit is inserted into the coupling socket provided at the lower end of the control rod in this state, and the pull-up handle is lowered, and the lock plug is lowered. By doing this, the coupling spud is pressed against the coupling socket and the control rod is connected to the control rod drive unit.
The pull-up handle is provided on the lower part support member of the control rod as shown in FIG. 2 of Japanese Patent Application Laid-Open 61-95277. The structure in the neighborhood of the lower part support member on which the pull-up handle is provided will be explained in detail by referring to
FIGS. 12 and 13
.
The constitution in the neighborhood of the pull-up handle
12
of the control rod is shown in FIG.
12
and the section XIII—XIII is shown in FIG.
13
. The pull-up handle
21
is inserted in the window provided in the lower part support member
7
and connected to the rod
13
inserted in the hole
18
with a nut. The thin parts
21
A are formed on the left and right of the pull-up handle
21
and the thin parts
7
A are formed in the neighborhood of each of the left and right sides facing on the window of the lower part support member
7
. The thin parts
21
A are fit between a pair of plates
22
attached to both sides of the thin parts
7
A by spot welding
23
respectively. The plates
22
are welded to the thin parts
7
A in the state that the ends of the thin parts
21
A are opposite to the ends of the thin parts
7
A. The pull-up handle
21
mounted inside the window will not be dislocated from the lower part support member
7
by the plates
22
.
The aforementioned conventional control rod requires a pair of plates
22
and has many parts. It is necessary to weld the pair of plates
22
, and there are many manufacturing processes, and it takes a lot of time to produce a control rod.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a control rod reducing the manufacturing processes.
The characteristic of the first invention for accomplishing the above object is that the present invention comprises a lower part support member attached at the lower end of the blade unit structured by arranging a neutron absorbing material in the sheath member having a U-shaped cross section and a handle unit which is arranged in the through hole provided in the lower part support member, connected to the lower part support member on the left and right sides, and can slide in the axial direction of the control rod, and grooves are made in the left and right sides of the handle unit, and thin parts are formed on the left and right sides of the lower part support member facing on the through hole over the sliding range of the handle unit respectively, and the left and right thin parts are inserted individually in the left and right grooves respectively so as to connect the handle unit to the lower part support member, and in the perpendicular direction to the axial direction, the first gap formed between the end of one thin part and the bottom of the groove in which the end is inserted is larger than the second gap formed between the end of the other thin part and the bottom of the groove in which the end is inserted.
Since the first gap is larger than the second gap, one of the left and right grooves is deeper than the other one and one of the left and right thin parts can be easily fitted into one groove mentioned above. The other thin part can also be fitted into the other groove easily. No plates are required unlike the conventional one and the handle unit is not dislocated from the lower part support member due to both side walls where the grooves are formed. The first invention forms grooves, so that the conventional blades are not required and the number of parts of the control rod can be reduced, so that the manufacturing processes are reduced and the time required for manufacture of a control rod is shortened.
The characteristic of the second invention for accomplishing the above object is that the cross section shape of the thin part forming the first gap has an inclined plane extending from one opposite side to the other side at its end, and a dent is formed on the longer side so that it becomes deeper linearly toward the base of the thin part from the end of the longer side, and the movement control unit for controlling movement in the perpendicular direction to the shorter side of the handle unit is formed on the longer side and on the end side from the dent.
According to the second invention, when the thin part is to be fitted into the groove, one of the side walls forming the groove is inserted into the dent, so that even if the thin part is not made thinner, no interference is caused between the thin part and the inner surface of the groove and the thin part can be easily fitted into the groove. Since the thin part is not made thinner, the gap between the thin part and the groove is small and the handle unit moves little in the thickness direction of the thin part due to the existence of the movement control unit. Since the handle unit is prevented from projection, the insertability of the control rod between the fuel collectors in the reactor center is not impeded.
REFERENCES:
patent: 3855732 (1974-12-01), Sheaf
patent: 5592520 (1997-01-01), Ledford et al.
patent: 5883931 (1999-03-01), Holden et al.
patent: 6137854 (2000-10-01), Ueda et al.
patent: 61-05277 (1986-05-01), None
Aizawa Yasuhiro
Gotoh Yasuyuki
Kawashima Norio
Kikuchi Yoshiharu
Koizumi Akira
Carone Michael J.
Hitachi , Ltd.
Mattingly Stanger & Malur, P.C.
Sukman Gabriel S
LandOfFree
Control rod and manufacturing method for the control rod does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Control rod and manufacturing method for the control rod, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Control rod and manufacturing method for the control rod will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2575494