JP5747248B2 - Fastening device for pulling out core upper mechanism - Google Patents

Description

  The present invention relates to a fastening device for collectively lifting a core upper mechanism that overlaps but is not integrated with each other and a liner located therebelow in a fast breeder reactor. For pulling out the upper core mechanism that uses a through-hole that is formed in the liner in a straight line, and the taper ring part inserted into the through-hole is expanded and deformed by the taper mechanism so that it is directly pressed against and locked to the liner. The present invention relates to a fastening device.

  In the construction of a large-scale plant, it is not necessary to carry out all assembly adjustments at the factory and then carry it into the plant construction site. May be adjusted. In that case, only the joint part is made into another part so that adjustment in the field is possible. In the fast breeder reactor “Joyo”, a liner is adopted as a spacer for adjusting the relationship between modules.

  In the above-mentioned fast breeder reactor, the liner is located below the core upper mechanism mounted in the reactor main body. In the extraction work of the core upper mechanism, it is necessary to extract the liner located below. The core upper mechanism includes an upper control rod mounting plate and a lower shield upper shell, which are connected but not connected to a liner located further below the shield upper shell. Also, due to the structure, the liner cannot be directly accessed from the outer peripheral side. A common through hole is provided in the control rod mounting plate, the shielding upper body, and the liner, but the lifting screw is not cut in the liner.

  If there is a wide space around the liner, it is possible to lift the liner with a large manipulator etc. at the same time as the core upper mechanism and lift it all together. Can't insert. If the bottom layer liner is threaded for collective lifting, it can be lifted by attaching eyebolts, but it will also generate chips in the post-processing of existing components. Cannot be adopted. Therefore, in the prior art, the core upper mechanism and the liner cannot be pulled out at the same time, resulting in separate lifting, resulting in poor work efficiency.

  By the way, the technique which fastens members using a taper mechanism is known conventionally, and the grasping device of the radioactive waste storage container using it is developed (for example, refer to patent documents 1). This is a device for gripping a waste container at an arbitrary position on its inner peripheral surface, and can be applied to lifting / hanging a single large-diameter container. However, this technique cannot be applied to the case where it is desired to lift the entire core upper mechanism and liner that are overlapped with each other but are not integrated and are free so that they do not deviate from each other.

Japanese Patent No. 4533961

  The problem to be solved by the present invention is that, in a fast breeder reactor, the core upper mechanism and the liner that are overlapped with each other but not integrated are collectively processed without any post-processing and without being shifted. To ensure that it can be lifted. Another problem to be solved by the present invention is that, while having a simple structure, it can be made compact so that it can be inserted into a common through-hole in the overlapping core upper mechanism and liner, and the holding reliability can be improved. It is providing the fastening device which can be performed.

In the fast breeder reactor, the core upper mechanism and the liner are formed in common in order to pull out the core upper mechanism that overlaps each other but is not integrated and the liner located therebelow. a fastening device for integrating both using a through hole, the through hole with male thread portion for positioning the upper end portion of the sleeve portion to be inserted is formed positionable diverging deformed downward to have A lock bolt having a tapered ring portion with a larger inner diameter and a male screw portion for tightening at the upper end of the shaft portion and a tapered taper portion at the lower end are inserted into the lock bolt. A positioning collar positioned above the core upper mechanism, and a positioning collar above the positioning collar. A tightening nut that is screwed with a male screw portion for tightening the taper bolt and pulls up the taper bolt, and the position of the taper ring portion is determined by the screwing position between the positioning collar and the lock bolt. The fastening for pulling out the upper mechanism of the core is characterized in that it can be adjusted to the position and the taper portion of the taper bolt is pulled up by tightening the tightening nut and the taper ring portion is expanded and deformed to lock the liner. Device.

Here, the lock bolt connects the sleeve portion and the tapering portion with a thin cylindrical body thinner than the tapering portion, and extends in the axial direction from the vicinity of the upper end of the thin cylindrical body to the lower end of the tapering portion. A structure in which a number of extending slits are formed at equal intervals is preferable. The slit is formed, for example, so as to equally divide the entire circumference into about 8 to 12, although it depends on the size of the lock bolt. These thin cylindrical bodies and slits fulfill the function of facilitating the expansion and deformation of the tapering portion.

  Moreover, it is preferable to provide a fall prevention mechanism at the lowermost end of the taper bolt. The fall prevention mechanism includes a plurality of locking pieces supported so as to be able to protrude and retract in the radial direction of the taper bolts, and a biasing spring that imparts an outward elastic force to each locking piece. The stopper is configured to protrude outward when the stopper is free at the lower position of the liner. Each locking piece may be a system that swings and opens in a vertical plane, or a system that enters and exits in a radial direction in a horizontal plane.

  Since the fastening device for pulling out the upper core mechanism according to the present invention uses a taper mechanism, the taper ring portion is expanded and deformed with a simple operation of only pulling up the taper bolt by tightening with the tightening nut, and is firmly Lock to the bottom liner. In addition, a large fastening force is generated with a small tightening torque, and since there is only one lock location, it can be made compact, and together, the reliability of fastening is improved as a whole. For this reason, there is no need to perform post-processing for lifting such as screw processing on the through hole. Although the fast breeder reactor has only a small space, this makes it possible to pull out the upper core mechanism and the liner together.

  Further, in the fastening device for pulling out the upper core mechanism according to the present invention, the position of the tapered portion can be adjusted to a specific depth by the combination of the lock bolt and the positioning collar, so that it can be reliably locked to the lowermost liner. . By inserting the sleeve portion of the lock bolt into the through hole, the taper ring portion is positioned substantially coaxially with the through hole, and locking is ensured. In addition, since the sleeve portion of the lock bolt can suppress the radial displacement of the free upper-layer core upper mechanism, the whole can be stably lifted up collectively.

  Furthermore, if a fall prevention mechanism is provided at the lower end portion of the taper bolt, the lowermost liner can be held even if the lock by the taper ring portion is loosened, so there is no possibility of a serious drop accident occurring. The fall prevention mechanism not only prevents the liner from falling, but also projects evenly toward the wall surface (radial direction), so it performs a centering function when inserting the fastening device into the through-hole, and penetrates even in narrow gaps. Even if there is some deviation in the hole, the fastening device can be reliably inserted.

FIG. 3 is a structural diagram of a fastening device for pulling out a core upper mechanism according to the present invention. Explanatory drawing of the use procedure. Explanatory drawing which shows an example of the use condition of a fastening apparatus. Explanatory drawing which shows the other example of the use condition of a fastening apparatus. Explanatory drawing which shows the other example of a tapering part. Explanatory drawing which shows the other example of a fall prevention mechanism part.

  FIG. 1 is a structural diagram of a fastening device for pulling out a core upper mechanism according to the present invention. Here, A shows a state in which each component is disassembled, B shows its xx cross section, and C shows a state in which the assembled fastening device is inserted into the through hole of the moving object and locked. This fastening device is used in a fast breeder reactor to lift the core upper mechanism and liner that overlap each other but are not integrated together, and uses a through-hole formed in both of them. And lock to the liner on the bottom layer.

As shown in FIG. 1A, the fastening device mainly includes a lock bolt 10, a taper bolt 12 inserted into the lock bolt 10 from below, a positioning collar 14, and a tightening nut 16. The lock bolt 10 includes a sleeve portion 20, a positioning male screw portion 22 formed at an upper end portion thereof, and a tapering portion 24 having a shape that can be expanded and deformed at a lower position and has a larger inner diameter. ing. The sleeve portion 20 and the taper ring portion 24 are connected by a thin-walled cylindrical body 26, so that the male screw portion 22, the sleeve portion 20, the thin-walled cylindrical body 26, and the taper ring portion 24 are integrated from above. The taper bolt 12 is formed with a male screw portion 30 for fastening at the upper end of the shaft portion 28 and has a tapered taper portion 32 at the lower end, and when inserted into the lock bolt 10, the male screw portion 30 for fastening. Protrudes upward from the lock bolt 10, and the tapered portion 32 fits into the tapered ring portion 24 of the lock bolt 10. The positioning collar 14 includes a female screw portion that is screwed with the positioning male screw portion 22 of the lock bolt 10. The tightening nut 16 is positioned above the positioning collar 14 and is screwed with the male screw portion 30 for tightening the taper bolt 12, and functions to pull up the taper bolt 12.

  Here, from the vicinity of the upper end of the thin cylindrical body 26 of the lock bolt 10 to the lower end of the tapering portion 24, a number of slits extending in the axial direction are formed at equal intervals on the entire circumference and divided. Although the number of slits formed is arbitrary, it is usually preferable to provide about 8 to 12 slits. In FIG. 1B, eight slits 34 are formed at equal intervals. The slit 34 has a function of smoothly performing the expanding deformation of the tapering portion 24, and the thin-walled cylinder 26 has a function of preventing the expanding deformation of the tapering portion 24 and keeping the entire lock bolt integrally. Plays.

  Further, a drop prevention mechanism 36 is provided at the lowermost end of the taper bolt 12. The fall prevention mechanism portion 36 includes a plurality of locking pieces 38 supported so as to be able to protrude and retract in the radial direction of the taper bolt, and when each locking piece 38 is in a free state, as shown by a solid line, the outward direction To protrude with its own weight. It is more reliable if the structure is such that a plurality of locking pieces that are swingable about the pin 40 are opened by the elastic force of the torsion spring. The stopper pin 42 functions to restrict the direction of the locking piece so that the locking piece does not reverse.

  The positioning collar 14 is screwed into the male screw portion 22 of the lock bolt 10 from above, and the depth position of the taper ring portion 24 is adjusted by the screwing position of the positioning collar 14 and the lock bolt 10. Then, the taper bolt 12 is inserted into the lock bolt 10 from below, and the tightening nut 16 is screwed into the male screw portion 30 for tightening the taper bolt 12 protruding from the upper end of the lock bolt 10. At this time, a washer 44 is interposed between the lock bolt 10 and the tightening nut 16. The taper portion 32 of the taper bolt 12 is not sufficiently fitted into the taper ring portion 24 of the lock bolt 10, so that the taper ring portion 24 is not yet expanded. Now you are ready.

  As shown in FIG. 1C, the assembled fastening device 50 is inserted into the through hole 52 of the moving object. Here, the moving object 54 includes a core upper mechanism 54a and a liner 54b that overlap each other but are not integrated. At this time, the locking piece 38 that is expanded by the fall prevention mechanism 36 performs a centering function, and is inserted while maintaining the state in which the central axis of the fastening device 50 substantially coincides with the central axis of the through hole 52. Then, the sleeve portion 20 of the lock bolt 10 is fitted into the through hole 52 of the moving object. When the lower end surface of the positioning collar 14 is placed on the upper surface of the core upper mechanism 54a, the positioning is performed, and the outer periphery of the tapering portion 24 just faces the through hole wall of the liner 54b. Since the sleeve portion 20 is fitted in the through hole 52, it is possible to minimize horizontal shakiness. Further, since the shaft portion 28 of the taper bolt 12 slides in the axial direction with respect to the sleeve portion 20 of the lock bolt 10, the taper portion 32 and the taper ring portion 24 are always kept in a coaxial state, and the position is stabilized. In this state, when the taper bolt 12 is pulled up by tightening the tightening nut 16, the taper portion 32 rises and the taper ring portion 24 is expanded and deformed by the taper mechanism. As a result, the outer peripheral surface of the tapering portion 24 comes into pressure contact with the through hole wall of the liner 54b. The liner 54b is locked to the fastening member 50 and can be lifted together with the upper core upper mechanism 54a.

2A to 2F show a procedure for using the fastening device 50. This is an example in which the moving object 54 composed of the upper core upper mechanism 54a and the lower liner 54b that are overlapped with each other but not integrated is lifted up in a lump as described above.
A: The fastening device 50 is inserted from above into the through hole 52 formed in common with the moving object 54.
B: When the lower end surface of the positioning collar 14 comes into contact with the upper surface of the upper core upper mechanism 54a, the fastening device 50 is positioned, and the outer peripheral surface of the taper part 24 just faces the through hole wall of the lower liner 54b.
C: In this state, when the tightening nut 16 is tightened and the taper bolt 12 is pulled up, the taper portion 32 rises, and the taper ring portion 24 is expanded and deformed by the taper mechanism. As a result, the outer peripheral surface of the tapered portion 24 comes into pressure contact with the through-hole wall of the liner 54b, and the fastening device 50 is locked to the liner 54b.
D: When the upper core mechanism 54a is lifted, the locked lower liner 54b is also lifted.
E: If it is further lifted as it is, and there is a gap between the liner 54b and the lower structure 56, the locking piece 38 of the fall prevention mechanism part opens, and the liner 54b can be prevented from falling.
F: Even if the lock by the taper mechanism is released or loosened and the liner 54b slips down, it can be received by the locking piece 38 of the fall prevention mechanism portion, so there is no possibility of falling below that. Absent.

  As described above, in the work of pulling out the core upper mechanism of the fast breeder reactor from the reactor main body, it is also necessary to pull out the liner provided at the lower part of the core upper mechanism. The core upper mechanism includes a control plate mounting plate located above and a shield upper shell located below, and both are coupled, but they are not coupled to the liner. Also, since the liner is contained within the reactor body, direct access to the liner is not possible.

  FIG. 3 schematically shows an example of lifting work using the device of the present invention. An upper core mechanism 62 closes the upper portion of the reactor main body 60, and a liner 64 is positioned below the upper core mechanism 62. Here, the core upper mechanism 62 and the liner 64 are moving objects. The upper core mechanism 62 and the liner 64 are provided with through holes 52 of the same size at the same location, and the through holes 52 reach the reactor main body 60. Many through holes 52 are formed in a circumferential shape, and the fastening device of the present invention is attached to a part (two or more) or all of them. In this example, eyebolts 66 are screwed into the core upper mechanism 62 at three locations symmetrical to the center, and lifting wires 68 are attached to the eyebolts 66 and lifted by a crane or the like. That is, the fastening device 50 is used exclusively for holding the moving object, and the eyebolt 66 bears the load of the moving object.

  As shown in A, the fastening device 50 is inserted into the through hole 52, and the fastening ring 16 is fastened in a state where the tapered ring portion 24 is positioned so as to face the liner 64. As a result, the tapering portion 24 is expanded and deformed, and the fastening device 50 is locked to the liner 64. The lifting preparation is now complete. When it is lifted as it is, as shown in B, the liner 64 is lifted together with the core upper mechanism 62. When a gap is generated between the liner 64 and the reactor main body 60, the locking piece 38 of the fall prevention mechanism portion is opened, and the fall can be prevented. Even if the lock is loosened and the liner 64 slips (in this case, the core upper mechanism 62 is lifted by the eyebolt 66 and does not fall), as shown in C, the liner 64 is supported by the locking piece 38. Therefore, there is no danger of serious fall accidents.

  FIG. 4 schematically shows another example of the lifting work using the device of the present invention. An upper core mechanism 62 closes the upper portion of the reactor main body 60, and a liner 64 is positioned below the upper core mechanism 62. Again, the core upper mechanism 62 and the liner 64 are moving objects. The upper core mechanism 62 and the liner 64 are provided with through holes 52 of the same size at the same location, and the through holes 52 reach the reactor main body 60. Many through holes 52 are formed in a circumferential shape, and the fastening device of the present invention is attached to a part (two or more) or all of them. In this example, a lifting wire 68 is directly connected to three fastening devices symmetrical about the center and lifted by a crane or the like. That is, the fastening device 50 is a system that performs both the function of holding the moving object and the function of bearing the load of the moving object.

  As shown in A, the fastening device 50 is inserted into the through hole 52, and the fastening ring 16 is fastened with the tapered ring portion 24 positioned so as to face the liner 64. As a result, the tapering portion 24 is expanded and deformed, and the fastening device 50 is locked to the liner 64. The lifting preparation is now complete. When it is lifted as it is, as shown in B, the core upper mechanism 62 is lifted together with the liner 64. When a gap is generated between the liner 64 and the reactor main body 60, the locking piece 38 of the fall prevention mechanism portion is opened, and the fall can be prevented. Even if the lock is loosened and the liner 64 and the upper core mechanism 62 slide down, as shown in C, since they are supported by the locking piece 38, there is no risk of a serious fall accident.

  FIG. 5 shows another example of the tapered portion 70. In this example, it is also effective to take an anti-slip measure on the outer peripheral surface of the tapering portion 70 (the portion surrounded by an elliptical dotted line in FIG. 5A). A surface to which anti-slip measures are taken is indicated by reference numeral 70a. Anti-slip measures include, for example, knurl processing and die (male thread) processing, a structure in which high-strength protrusions are attached, and a method that uses the seizure effect by using the same material as the opposing liner. B shows the yy cross section of A, and here, the slits 72 are formed so that the entire circumference of the tapered portion 70 is divided into 12 equal parts. Since the other structure may be the same as that of FIG. 1, it attaches | subjects the same code | symbol and abbreviate | omits description.

  FIG. 6 shows another example of the fall prevention mechanism. The fall prevention mechanism also includes a plurality of locking pieces supported so as to be able to protrude in the radial direction of the taper bolts, and a biasing spring that applies an outward elastic force to each locking piece. The stop piece is configured to be free at a position below the liner and project outward. Here, each locking piece 74 is made to enter and exit horizontally, and is biased by a coil spring 76. 6A shows a state in which the locking piece 74 is pushed in, and B shows a state in which the locking piece 74 is free and protrudes (a state in which the fall prevention function is working). About 2 to 4 locking pieces 74 are provided symmetrically with respect to the central axis of the taper bolt. Also in this case, a centering function when inserting the fastening device into the through hole can be expected. Since the other structure may be the same as that of FIG. 1, it attaches | subjects the same code | symbol and abbreviate | omits description.

DESCRIPTION OF SYMBOLS 10 Lock bolt 12 Taper bolt 14 Positioning collar 16 Tightening nut 20 Sleeve part 22 Positioning male thread part 24 Taper ring part 26 Thin walled body 28 Shaft part 30 Tightening male thread part 32 Taper part 34 Slit 44 Washer 50 Fastening Device 52 Through-hole 54 Moving object 54a Core upper mechanism 54b Liner

Claims (4)

In the fast breeder reactor, in order to pull out the core upper mechanism that overlaps each other but is not integrated and the liner located therebelow, a through-hole formed in the core upper mechanism and the liner is formed in common. A fastening device that uses both to integrate,
A lock bolt provided with a male screw portion for positioning at the upper end portion of the sleeve portion to be inserted into the through-hole and having a tapered ring portion which is positioned below and can be expanded and deformed and the inner diameter is increased downward, and a shaft A male screw portion for tightening is formed at the upper end of the portion, and a taper bolt portion having a tapered shape at the lower end is inserted into the lock bolt, and a male screw portion for positioning the lock bolt is screwed together. A positioning collar provided with a female screw portion and positioned above the core upper mechanism, and a tightening nut positioned above the positioning collar and screwed with a male screw portion for tightening the taper bolt to pull up the taper bolt The position of the taper ring portion can be adjusted to the position of the liner by the screwing position of the positioning collar and the lock bolt, and the tightening nut Fastening device for upper core structure abstraction, wherein the pulling the tapering portion a tapered portion of Tepaboruto by fit with by causing deformed and opened it has to be locked to the liner. The sleeve portion and the tapering portion of the lock bolt are connected by a thin cylindrical body thinner than the tapering portion, and many axially extend from the vicinity of the upper end of the thin cylindrical body to the lower end of the tapering portion. The fastening device for pulling out the upper core mechanism according to claim 1, wherein the slits are formed at substantially equal intervals.   A drop prevention mechanism portion is provided at the lowermost end of the taper bolt, and the drop prevention mechanism portion includes a plurality of locking pieces supported so as to be able to protrude and retract in a radial direction of the taper bolt, and each locking piece is the liner. 3. The fastening device for pulling out the upper core mechanism according to claim 1 or 2, wherein the fastening device is configured to be in a free state and project outwardly at a lower position.   The fastening device for pulling out the upper core mechanism according to claim 3, wherein the fall prevention mechanism includes a biasing spring that imparts an outward elastic force to the locking piece.

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