JPH0616381Y2 - Underwater transfer system for nuclear fuel assemblies - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a submerged transfer device for a nuclear fuel assembly used in a nuclear power plant.

[Prior Art] In a nuclear power plant, in order to carry a fuel assembly into a reactor containment vessel or carry out a spent fuel assembly taken out of the reactor from the containment vessel, The fuel transfer device provided in the fuel transfer canal that leads from the reactor cavity to the spent fuel pit on the fuel handling building side is used. FIG. 5 shows an outline of such a fuel transfer device.

In FIG. 5, the fuel container 5 accommodating the nuclear fuel assemblies 2 is carried horizontally on the rails 7 from the fuel handling building to the containment vessel or vice versa by the carrier 4 having the wheels 3. When it reaches the position of the lifting frame 6, it automatically stops. At this time, a claw (not shown) provided at the tip of the lifting frame 6
When the lifting frame 6 is rotated by the wire rope 8 and rises, the container 5 pivotally attached to the carrier 4 by the rotation pin 5a also rotates and rises. In the figure, the two-dot chain line shows the standing state of the container 5 and the lifting frame 6.

Further, the fuel transfer device has the impact absorbing device 1 in order to absorb the impact when the standing state is changed to the horizontal state indicated by the solid line. FIG. 6 shows a detailed cross section of the shock absorbing device 1. The shock absorbing device 1 includes a cylinder 1a erected on a base and a piston 1b in the cylinder 1a.
And a piston rod 1c extending upward from the piston 1b,
A receiving portion 1d provided at the tip of the piston rod 1c, a compression coil spring 1e surrounding the piston rod 1c between the receiving portion 1d and the upper end of the cylinder, and a smooth operation of the piston 1b and the piston rod 1c. It is composed of a bush 1f provided at the illustrated position.

[Problems to be Solved by the Invention] However, in the shock absorbing device 1 having such a structure, when the lifting frame 6 is in the standing state as shown by the chain line in FIG. 6 is located at the position shown in FIG. 6, so that the bush 1f is likely to be stuck to the piston rod 1c. When such a problem occurs, the piston rod 1c is fixed, and therefore it is impossible to lower the lifting frame 6 to the position shown by the solid line in FIG. 5 because the piston rod 1c becomes an obstacle. Moreover, since the main body of the fuel transfer device is installed in water, it is not easy to approach the installation site to restore the shock absorbing device 1, and therefore the fuel transfer must be stopped.

Therefore, it is an object of the present invention to provide an underwater moving device that does not need to stop the subsequent fuel transfer even if a problem occurs in the shock absorbing device.

[Means for Solving Problems] To this end, the submerged transfer device for a nuclear fuel assembly according to the present invention has a rail laid in water and a container for accommodating the nuclear fuel assembly pivotally mounted on the rail. A reciprocating carrier, a container tilting mechanism arranged near the starting point and the end point of the rail, and a shock absorbing device arranged near the starting point and the end point, and the base of the shock absorbing device is a pin. The base is provided with a fixed latch that can be opened and closed, and the operation wire is connected to the fixed latch. When the operation wire is pulled up, the fixed latch is opened to tilt the impact absorbing device. The feature is that it becomes possible.

[Operation] During normal operation, the fixed latch holds the shock absorber in the upright state to prevent it from tilting. If a problem occurs in the shock absorbing device during the transition of the container tilting mechanism from the vertical state shown by the chain line in FIG. 1 to the horizontal state shown by the solid line, the container tilting mechanism is once moved to the position shown by the chain line in FIG. After returning, when the operating wire connected to the fixed latch is pulled upward from the air, the fixed latch is released. Therefore, when the operation wire is further pulled up, the base is moved upward via the fixed latch, and the shock absorbing device 1 is tilted as shown in FIG. 4, and the subsequent operation of the container tilting mechanism is not hindered.

[Embodiment] Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding portions.

FIG. 1 shows an outline of an underwater fuel transfer device embodying the present invention. In this underwater transfer device, similarly to the conventional case, a rail 7 laid in water and a container 5 accommodating a nuclear fuel assembly 2 are pivotally mounted by a rotating pin 5a, and a carrier 4 with wheels 3 reciprocally moving on the rail 7. It has and. Rail 7
Generally, it extends between the start point and the end point, that is, between the reactor cavity on the side of the containment vessel (not shown) and the spent fuel pit on the side of the fuel handling building. For convenience, FIG. 1 shows the end point of the rail 7 in the spent fuel pit 9. It shall indicate the neighborhood.

Although only the end point side is shown in FIG. 1, a container tilting mechanism including, for example, a lifting frame 6 and a wire rope 8 is provided both near the start point and the end point of the rail 7. As is well known, the container 5 accommodating the fuel assembly 2 is transported in a horizontal state between the start point and the end point as indicated by the solid line, stops when reaching the vicinity of the start point and the end point, and is connected to the lifting frame 6 and it. Due to the action of the wire rope 8, the fuel assembly 2 is tilted to the standing or vertical state shown by the chain line in FIG. 1 for taking out or inserting the fuel assembly 2. Further, in order to protect the container 5 from impact when the vertical state is changed to the horizontal state, the impact absorbing device 1 is arranged near the start point and the end point.

2 to 4 show the details of the impact absorbing device 1 described above. In the figure, the shock absorbing device 1 includes a cylinder 1a,
A piston 1b in the cylinder 1a, a piston rod 1c extending upward from the piston 1b, a receiving portion 1d provided at the tip of the piston rod 1c, and a piston rod 1c between the receiving portion 1d and the cylinder upper end portion. And a compression coil spring 1e surrounding the. A base 20 having a plate body 20a extending downward is attached to the lower end of the cylinder 1a.

On the other hand, on the bottom surface 17 of the spent fuel pit, the substrate 16a
The base 16, which is composed of a pair of support plates 16b spaced apart from each other and extending vertically upward from the substrate 16a, that is, the mount 16, is fixed by an appropriate means. The plate body 20a described above is provided between the support plates 16b.
Is extended and pivotally attached by the pin 13, so that the base 20 of the shock absorbing device 1 is pivotally attached to the mounting base 16.

A support base 20b is attached to the lower surface of the base 20.
A fixed latch 11 having an arm 11b is openably and closably supported on 0b. The eye fitting 14 connected to the operation wire 12 extending above the liquid level of the spent fuel pit 9 is connected to the base 20.
Through a non-contact state and is connected to the free end of the arm 11b. Further, a receiving portion 11a capable of holding the latch 11 is provided upright from the board 16a of the mounting base 16. In addition, 10 is a weight for preventing the rattling of the cylinder 1a, 15 is a metal fitting which is attached to the lifting frame 6 and abuts on the receiving portion 1d of the shock absorbing device 1, and 18 is a stopper provided on the plate body 20a. Is.

A shock absorbing device 1 constructed as described above according to the present invention
In the fuel transfer apparatus having the above, the fixed latch 11 is engaged with the receiving portion 11a during normal operation to hold the shock absorbing device 1 in the upright state and prevent the tilt thereof. Also, the stopper
10 prevents rattling. If a problem occurs in the shock absorbing device 1 during the transition from the vertical state shown by the chain line in FIG. 1 to the horizontal state shown by the solid line, the lifting frame 6 is once returned to the vertical position shown by the chain line in FIG. After that, pull the operating wire 12 upwards, and
b is pulled upward, and the fixed latch 11 is disengaged from the receiving portion 11a. Therefore, if you pull up the operating wire 12 further,
The impact absorbing device 1 is tilted as shown in FIG. 4 by the contact of 11b with the base 20, and the operation of the lifting frame 6 thereafter is not hindered.

[Advantage of the Invention] As described above, according to the present invention, even if a problem occurs in the shock absorbing device, the shock absorbing device can be tilted to a position that does not hinder the operation of the container tilting mechanism from a distance. Since the backup operation for the occurrence of the trouble can be performed, the operation of the fuel transfer device can be continued thereafter.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an underwater transfer device for fuel embodying the present invention, and FIG. 2 is a side view showing a partial cross section of an impact absorbing device used in the underwater transfer device of FIG. FIG. 3 is an elevational view showing the impact absorbing device of FIG. 2 in a partial cross section when viewed from the direction of arrow III, and FIG. 4 shows the state of the impact absorbing device of FIG. 2 when a problem occurs. A side view, FIG. 5 is a schematic side view of a conventional underwater transfer device, and FIG. 6 is a detailed cross-sectional view of an impact absorbing device used in the underwater transfer device of FIG. 1 ... Impact absorbing device, 2 ... Nuclear fuel assembly 4 ... Carrier, 5 ... Container 6 ... Lifting frame (Container tilting mechanism) 7 ... Rail 8 ... Wire (Container tilting mechanism) 11 ... Fixed Latch, 12 …… Operating wire 13 …… Pin, 16 …… Mounting base (base) 20 …… Base

Claims (1)

[Scope of utility model registration request] 1. A rail laid in water, a container for accommodating a nuclear fuel assembly pivotally mounted therein, a carrier that reciprocates on the rail, and a tilting container disposed near the start and end points of the rail. A mechanism and a shock absorbing device arranged near the start point and the end point, the base of the shock absorbing device is pivotally attached to the base through a pin, and the base is provided with a fixed latch that can be opened and closed to operate. A submerged transfer device for a nuclear fuel assembly, wherein a shock absorbing device can be tilted by connecting a maintenance wire to the fixed latch and opening the fixed latch when pulling up the operation wire.