JPS6073305A - Clearance gauge for nuclear fuel aggregate body - Google Patents

Abstract

PURPOSE:To effect arbitrary selection of gauge blade of different thickness with a single pole, by installing a number of gauge blades free to rise and fall at the end of the pole and allowing a blade to rise selectively with a mechanism provided at the rear end of the pole. CONSTITUTION:On four surfaces of a square pipe 4 at the bottom of a pole 1 made of a pipe, gauge blades 5a-5h of different thicknesses are attached by two pieces on each surface respectively free to rise and fall. On four surfaces of a square-pawl assembly 8 at the bottom of a shaft 6, pawl 9a-9h with two teeth for each surface respectively are mounted at the specified height. Around rotating shafts 13a-13h, of individual blades 5a-5b are studded with pins 14a-h, 15a-h, 16a-h in the angular positions of 90, 120, 180 deg.. When strokes of in-and- out motions of a shaft 6 through a handle 7 is adjusted and one of the pins 15a-h is engaged with one of the corresponding pawl in grooves 11a-h, the desired blade is permitted to rise.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a gap gauge for a nuclear fuel assembly in a nuclear reactor, and more specifically, to a gap gauge for a nuclear fuel assembly in a nuclear reactor. The present invention relates to a feeler gauge for nuclear fuel assemblies that checks whether or not the value is above a reference value by pushing the gauge blade.

[Prior art]

In nuclear fuel assemblies that have been loaded into the core of a nuclear reactor more than once,
It is said that the fuel rods are bent to some extent, which causes the gap between adjacent fuel rods to become smaller. If the size of this gap becomes smaller than the standard value and there are parts where the fuel rods are too close to each other, the nuclear fuel assembly cannot be reused as it is. Therefore, before reuse, it is necessary to check whether the gap is equal to or greater than the standard value. Conventionally, a metal plate (gauge blade) of a predetermined thickness was attached to the tip of the ball, protruding sideways. Use the gauge as a feeler gauge, suspend this gauge by the tail end of the ball from a crane,
Insert the blade into each gap between the plurality of fuel rods from the outside of the side of the nuclear fuel assembly, and inspect each gap from the top to the bottom by changing the thickness of the blade and performing the same insertion operation. Ta. In such conventional feeler gauges, in order to insert gauge blades of different thicknesses, for example, two blades are inserted at the tip of one ball at 180 degree intervals, or two gauge blades are inserted at 90 degrees.
Four gauge blades are installed at intervals of 50 degrees, and are mounted so as to protrude sideways, and the blades are selected by rotating the ball using a crane. Since it is a fixed type, when it is necessary to insert a gauge blade of a different thickness, the ball must be resuspended, and this involves a process such as moving the Bretsuge crane. Inconveniences such as the complexity of the gap investigation process and the increased time required were unavoidable.

Also, since there were so many balls, it was necessary to have a large storage area.

[Summary of the invention]

This invention was made with the aim of improving this drawback, and has a larger number of gauge blades than the conventional ones at the tip of the ball, each of which can be raised and lowered. By operating the tail end, you can selectively raise only the desired gauge blades and leave the others down, allowing you to manufacture various thicknesses with a single ball without having to change the suspension of the ball. This paper proposes a feeler gauge for nuclear fuel assemblies in which gauge blades can be selected arbitrarily.

[Embodiment of the Invention] FIG. 1 is a front view showing an embodiment of the invention, with part of the middle of the ball being omitted. In FIG. 1, a ball 1 is made of a pipe, and a flange member 2 is fixed to the upper part of the ball 1, and a hanging metal fitting 6 for hanging the crane is attached to the seven-rank member 2. The lower end of the ball 1 is a square pipe 1 (4), and on each of its four sides there are gauge blades 5a of two different thicknesses.
5b...5h are attached so that they can be raised and lowered individually. A shaft 6 is built into the ball 1 so as to be slidable in the axial direction.A handle 7 is attached to the upper end of the shaft 6 at a position above the flange member 2, and the lower end is used for raising and lowering the blade. A pawl assembly 8 is attached. As shown in FIG. 2, the claw assembly 8 has two claws 9a and 9b on each of the four sides of a prismatic main body connected to the shaft B.
...9h", and the axial positions of these winter melons are shifted one by one. This claw assembly 8 moves the inside of the square vibrator part 4 axially by inserting and removing the handle 7. There are slits 10a on each surface of the square pipe portion 4 through which the winter melons 9a to 9h of the claw assembly 8 protrude outward over the stroke range of this relative movement.
, 10b...10h are provided.

If we talk about the gauge blade up/down operation mechanism, the first one is
See also FIG. 3, which is an enlarged view taken along arrow A-A in the figure, and FIG. 4, which is an enlarged view taken along arrow B-B of the figure.
Claws 9a, 9b... protruding from 10b...
Three bottles are installed on the rotating shaft of each blade so that they can be engaged with the grooves 11a, 11b, etc. between the two peaks of the blades. i.e. 3rd and 4th
Regarding the blade 5b shown in the figure, the gauge blade 5b is rotatable within a range of 80 degrees and 0 degrees and 90 degrees by a bearing 12b with a detent mechanism on the outer surface of the square pie 1 part 4. , is pivoted so that the wheels can be parked at three points at 180 degrees.

Around the rotation axis 13b of the blade 5b, there are the above-mentioned 0 degrees, 9
Bins 14b and 15 are placed at the corresponding positions of 0 degrees and 180 degrees, respectively.
b, 16b are implanted, and as shown in FIG. 4, the bin 15b at the 90 degree position engaged with the ellb of the corresponding claw 9b is directly to the left of the rotating shaft 13b (9 o'clock position in FIG. 4). The blade 5b is configured to stand up at right angles to the ball 1 when the blade 5b is positioned at the ball 1. As shown in Figures 3 and 4, the claw 9b
When the pin 15b moves upward, the pin 15b moves into the groove 11 of the claw 9b.
The blade 5b moves upward while being engaged with the blade 5b at the time B1.
When the pin 14I, which is at the exactly 0 degree position, reaches the 9 o'clock position in Figure 4, the top of the peak (lower peak) of the claw 9b will come out (') further upward. As the blade 5b turns downward, it folds along the ball and pierces through.On the contrary, the claw 9b moves downward compared to the state shown in Figs. 6 and 4, and the pin 15b merges into the groove 11b of the claw 9b. 14, the blade 5b rotates counterclockwise, and when the position 16b is exactly 180 degrees at the 9 o'clock position of hour 1 in Fig. 4, the peak of the claw 9b (upper peak) As the top of the blade begins to pull out further downwards, the blade 5
B is folded face up along the ball. Although only the gauge blade 5b has been described in detail here, such a mechanism is the same for the other blades, the only difference being that the phases of the ups and downs due to rotation of each blade are shifted. In Figure 5, which schematically shows the phase shift of the bumps and undulations, the same symbols as in Figures 1 to 4 indicate the same parts, which are hidden in Figure 1 in order from the left in this figure. The relative positional relationships between the gauge blades 5a to 5h and the claws 9a to 9b are shown in correspondence with the states shown in FIGS. 1 to 4.

Regarding the blades, when the blade on the left side is facing upwards and the blade on the right side is facing downwards, it stands up at right angles to the ball. In FIG. 5, the blade 5b is just standing up, and at this time the blade 5b
The blade a faces upward, and the other blades 50 to 5h face down. When the shaft 6 is moved upward from this state, the blades 50 to 5h do not move, but the blades 5a and 5b rotate counterclockwise, and just when the blade 5a rotates 90 degrees and stands up, the blade 5b moves. It becomes a state of lying face down. Conversely, if the shaft 6 is moved downward from the state shown in FIG.
- 5h does not move downward, the blades 5b and 5c rotate clockwise, and when the blade 5c rotates 90 degrees and stands up, the pre-blade 5b is in a state of lying upward.

By predetermining the axial position of the winter melons 98 to 9h in this way, only the desired gauge blade can be erected by adjusting the stroke of inserting and withdrawing the shaft B by operating the handle 7. Since it is possible to judge which blade has stood up from the way the shaft B protrudes from the flange member 2 side, it is also possible to attach a scale to the shaft in this part. Although an example in which the blades are made into two blades has been given, it is also possible to attach a larger number of blades, and the present invention does not particularly limit the number of blades.

〔Effect of the invention〕

As described above, according to the present invention, the conventional gauge blade with multiple balls could not be attached to a single ball, but the ball could be hung by a crane to change the thickness of the blade. There is no need to change the blade (all blade selection operations can be done on the upper end of the 7th and 11th balls).
Additionally, all the blades can be folded up when not in use, which means less space is needed for storage.

[Brief explanation of drawings]

Fig. 1 is a partially omitted front view showing an embodiment of the present invention, Fig. 2 is a perspective view of the pawl assembly, Fig. 6 is an enlarged view taken along line A-A in Fig. 1, and Fig. 4 is FIG. 6 is a view taken along line B-B in FIG. 6, and FIG. 5 is a schematic diagram for explaining the up-and-down motion. 1: Ball, 2: Flange part, 3 = Hanging metal fitting, 4: Square pipe part, 58~5h nigage blade, 6: Shaft, 7: ]・ndle, 8: Claw assembly, 9a~9h: Claw ,1
0a to 10h Nislit, 11a to 11h: Groove, 12a
~12h: Bearing with stop wheel mechanism, 14a, b, 15n, b,
16a, b: Bin 0 agent Patent attorney Sanro Kimura

Claims (2)

[Claims] (1) In the feeler gauge, a gauge blade of a predetermined thickness is inserted into the gap between the fuel rods of a nuclear fuel assembly to check whether the gap between adjacent fuel rods is greater than or equal to a reference value. A plurality of gauge blades of various types and known thicknesses are each attached to the tip so that they can be raised and lowered, and only a desired blade from among the gauge blades is selectively raised and put into use by operating a handle on the upper end side of the ball. A feeler gauge for a nuclear fuel assembly, characterized in that a mechanism is incorporated in the ball. (2) The operating mechanism includes a shaft slidable in the axial direction within the ball, a handle attached to the shaft at the upper end of the ball, and a plurality of claws fixed to the shaft at different stroke positions at the lower end of the ball. and a pin which is embedded in the pivot fulcrum of each gauge blade and engages with one of the pawls in a corresponding manner to rotate the gauge blade to perform a raising and lowering operation. A feeler gauge for a nuclear fuel assembly according to claim 1, characterized in that: