JPS5845644B2 - sodium fluoroscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sodium fluoroscopy system, and in particular, it utilizes a hold-down arm of a fuel exchange machine to enable the top of a fuel assembly to be observed over a wide area in a short time, thereby reducing the work time before fuel exchange. (It is possible to improve the operation rate of the nuclear reactor).

The interior of fast breeder reactors, especially those that use liquid metal as a coolant, cannot be directly observed with the naked eye.

For this reason, fast breeder reactors are observed indirectly using transducers that transmit and receive ultrasonic waves.

By the way, the sodium fluoroscopic device using this transducer is installed using the fuel exchanger hold-down arm on the same rotating shield plug as the fuel exchanger, so the rotating shield plug and hold-down arm can also be rotated by the fluoroscopic device. After viewing the entire top of the fuel assembly to be gripped, the viewing device must be removed and the refueling device installed.

The time required to use this sodium fluoroscope directly affects the operating rate of the reactor.

Therefore, it is necessary to reduce as much as possible the time required for the fluoroscopy device to observe the top of the fuel assembly and the time required for installation and removal of the fluoroscopy device. It is necessary to have a mechanism that reduces arm operating time and has fewer failures.

In order to shorten the usage time of the above-mentioned sodium fluoroscopy device, there is a method of installing the fluoroscopy device on the same rotating shield plug as the refueling machine, but this requires increasing the dimensions of the reactor structure in order to take up the installation space. This would be impractical from an economic point of view.

The present invention has been made in view of the above-mentioned circumstances, and is capable of further holding down a fuel exchanger by operating a transducer holder configured to be removably attached to a hold-down arm of a fuel exchanger using a drive unit installed on a rotary shielding plug. The purpose of the present invention is to obtain a sodium fluoroscopy device that can directly observe the top of the fuel assembly from the lower end of the fuel exchanger hold-down arm by rotating the arm and rotating the rotary shield plug.

The present invention will be described below with reference to the drawings of one embodiment.

FIG. 1 is a schematic vertical sectional view showing an embodiment of the present invention.

In FIG. 1, a sodium fluoroscopy device penetrates a rotating plug 3 of a reactor vessel 2 containing a sodium coolant 1;
It has a driving part 5 on the upper part, a rotating housing 7 on the lower part that reaches near the reactor core 6 in sodium, and a scanning guide 8 mounted on a shaft at the tip of the rotating housing 7 parallel to the upper surface of the reactor core 6.

FIG. 2 shows the drive mechanism of the fluoroscopic device.

A transducer holder 9, which has a large number of transducers 24 arranged in several stages in a dense manner in the scanning direction C inside the scanning guide 8, is rotatably supported at both ends by bearings 20 and 21, and is threaded. It is in screw contact with a certain scanning shaft 10 and is supported by guide rails 19 on both sides.

The scanning shaft 10 is a rotating shaft 1 connected to a drive section in the drive section 5.
3 and universal joint 11 and bevel gear 12
are connected via.

The universal joint 11 is located on a shaft in which the rotating housing 7 and the scanning guide 8 are mounted on a locking shaft 18 .

A lifting rod 14 connected to the drive unit in the drive unit 5 inside the rotary housing 7 is attached to a guided roller 15 , and the tag roller 15 is connected to the scanning guide 8 via a folding arm 16 .
It is mounted on a shaft with a bin 17.

Next, the operating state of the IJum fluoroscope described above will be explained.

FIG. 1 shows a state in which the scanning guide 8 of the sodium fluoroscopy device rotates A and scans the upper surface of the core 6 in the sodium coolant 1.

By rotating the rotary plug 3 and moving the position of the sodium fluoroscopy device, the scanning target range can be expanded.

Figure 2 shows the driving mechanism of the sodium fluoroscopy device.
The rotating shaft 13 and the rotating housing 7 are independently driven and rotated by a driving section provided on the upper part of the rotating plug 3.

First, the rotation E of the rotating shaft 130 is transmitted through the bevel gear 12 and the universal joint 11 to rotate the scanning shaft 10. The rotation of the scanning shaft 10 moves the transducer holder 9, which is in screw contact, along the guide rail 19 C. let

When the rotating housing 7 rotates A, the scanning guide 8 also rotates A.
Therefore, by the movement C and the rotation A, the transducer holder 9 can scan the upper surface of the core 6 over a wide range.

By moving the pulling rod 14 up and down, the folding arm 16 moves the scanning guide 8 to the locking shaft 18 via the roller 15.
It can be rotated B using the rotation housing 7 as a fulcrum to store it inside the rotating housing 7, or to unfold it or fold it.

The universal joint 11 on the axis of the time stop shaft 18 is capable of following the rotation B.

As explained above, the present invention is capable of scanning a wide range of the upper surface of the core in the IJM coolant, making it possible to display the mutual positional relationship of core components, and moreover, scanning within a short period of time. Since this is possible, the period during which the reactor is out of operation will be shortened and its operating rate will be increased.

Furthermore, since it is no longer necessary to hold the transducer at high temperatures for a long time, it is possible to reduce malfunctions of the IJ fluoroscopic device, thereby reducing transducer failure and life expectancy.

Since a scanner composed of a large number of transducers is used, even if several transducers fail, the functionality of the sodium fluoroscopy device will not be lost at all.

Additionally, since the folding mechanism has a simpler structure than the conventional pantograph system, the transducer drive mechanism and arm folding mechanism have stronger mechanisms, increasing equipment reliability and, in turn, improving reactor operating efficiency.

Furthermore, by using the rotation of the rotating plug, the scanning range of the sodium fluoroscopy device can be extended to the entire core structure, allowing macroscopic observation of the inside of the reactor, expanding the range of use to the field of reactor interior inspection equipment, and increasing its utility value. becomes higher.

Additionally, the sodium fluoroscopy system utilizes the hole gran arm of the fuel exchanger, so it has the advantage of being able to be installed without changing the dimensions of the reactor structure.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the installation of the sodium fluoroscopy device of the present invention.
FIG. 2 shows the drive mechanism section of FIG. 1, with a being a longitudinal sectional view thereof and b being a plan view thereof. 5... Drive unit, 7... Rotating housing, 9... Transducer holder, 16...
...Folding arm, 24...Transducer.

Claims (1)

[Claims] 1. A rotating housing fixed to the hold-down arm of the fuel exchanger, a folding arm rotatably provided below the rotating housing, and a horizontally movable transducer holder provided within the operating guide of the folding arm. a plurality of transducers attached to the lower surface of the transducer holder; and a drive section that is detachably installed on the upper surface of the attachment part of the hold-down arm and horizontally moves the transducer holder and opens and closes the folding arm. Constructed sodium fluoroscope.