JPS5832679B2 - 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. The present invention also relates to a sodium fluoroscopy device that can improve the operating rate of a 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 fluoroscope also rotates the rotating shield plug and hold-down arm. 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 the time required for the fluoroscopy device to observe the top of the fuel assembly and the time required for installing and removing the fluoroscopy device as much as possible. It is necessary to have a mechanism that shortens the operating time of the folding arm and has less failure.

In order to shorten the operation time of the transducer drive mechanism, there is a method in which a large number of transducers are closely attached to a transducer holder and the holder is moved back and forth using a ball screw within the operation guide, but if the operation stroke is long, the holder's It is difficult as a mechanism to enable the signal cable of the transducer to follow horizontal movement, and cable handling when the arm is folded is extremely difficult and impractical.

The present invention was made in view of the above-mentioned circumstances, and a large number of transducers are arranged at roughly equal intervals throughout the arm direction in a transducer holder configured to be removably attached to a hold-down arm of a fuel exchanger. A mechanism has been installed to shorten the distance, shorten operating time, and make it easier to follow the signal cable, as well as to facilitate cable handling when the arm is folded, allowing for horizontal movement and rotation of the transducer holder and rotation of the shielding plug and hold-down arm. The purpose of this study is to obtain a sodium fluoroscopy device that allows the top of a fuel assembly to be directly observed from the lower end of a fuel exchanger hold-down arm.

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

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

In FIG. 1, a rotating housing 7 passes through the rotating plug 3 of the reactor vessel 2 in which the sodium coolant 1 is sealed, has a driving part 5 at the upper part, and reaches near the reactor core 6 in the 1-IJ atmosphere at the lower part. A scanning guide 8 is mounted on the tip of the rotary housing 7 in parallel with the upper surface of the reactor core 6.

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

A transducer holder 9 in which a large number of transducers 24 are arranged at roughly equal intervals in the scanning direction C inside the scanning guide 8 is supported by rollers 20 and 21 on both sides so as to be horizontally movable, and is connected to the scanning guide 8 and the transducer holder 9. Vessel 9
A coil spring 10 is inserted between the
It is being pushed to 2.

The constant velocity cam 12 is connected to a rotating shaft 13 that is connected to a drive section in the drive section 5 .

The upper surface level of the transducer holder 9 is on an axis on which the rotating housing 7 and the scanning guide 8 are mounted on a stop shaft 18 to avoid friction with the cam 12 when the arm is folded.

A pulling rod 14 connected to the drive unit in the drive unit 5 inside the rotating housing 7 is attached to a guided roller 15;
The roller 15 is pivotally mounted on the scanning guide 8 via a folding arm 16 with a pin 17 .

The cable guide 11 guides the signal cable 25 of the transducer so that it does not twist apart, and also guides it with a fixed bending radius when the folding arm 16 is pulled up.

Next, the operating state of the sodium fluoroscopy device will be explained.

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

By rotating the rotary plug 3), the scanning target range can be expanded by moving the position of the IJum fluoroscope.

FIG. 2 shows the drive mechanism of this fluoroscopic device, in which the rotating shaft 13 and the rotating housing 7 are independently driven and rotated by a drive section provided on the upper part of the rotating plug 3. First, the rotating shaft 13 rotates E. The constant velocity cam 12 is rotated, and the transducer holder 9 is horizontally moved along the guide rail 19 by a stroke determined by the compression force of the coil spring 10.

A fixed stroke is equal to the spacing between adjacent transducers.

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 thoroughly scan the upper surface of the core 6 over a wide range.

In addition, by moving the pulling rod 14 up and down, the roller 1
5, the folding arm 16 can rotate the scanning guide 8 around the stop shaft 18 as a fulcrum, allowing it to be stored inside the rotary housing 7 or unfolded. Since it is located on the top surface of the retainer 9, the transducer retainer 9 and the constant velocity cam 12
There is no particularly strong friction between the two.

Further, when the scanning guide 8 is housed in the rotation housing 7, the scanning guide 8 is prevented from falling down by the stopper 27.

Further, since the operating stroke of the transducer holder 9 is short, the signal cable 25 is guided and bent by the cable guide 11, and can be easily processed even in sodium.

As explained above, the present invention can scan the top surface of the core in the I-IJ coolant over a wide range, so the mutual positional relationship of the core components can be displayed, and moreover, the scanning can be done in a short time. Since nuclear reactor operation can be reduced, the period during which nuclear reactor operations are shut down is shortened and its operating rate is increased.

Also, since the transducer does not need to be kept at high temperatures for long periods of time, malfunctions of the sodium fluoroscope due to transducer failure and life span can be reduced.

The inspection area can cover the top surface of the core in a single time by operating the transducer holder, rotating shield plug, and hold-down arm, so even if one transducer fails, the functionality of the I-IJ fluoroscopy system remains intact. It is not lost at all.

The folding mechanism also eliminates the need for ball screws and universal joints compared to conventional systems, and the operating stroke of the transducer holder is short and cable handling is easier, resulting in a simpler structure. This will improve the reliability of the equipment and, in turn, improve the operating rate of the reactor.

Furthermore, by using the rotation of the rotating plug, the scanning range of the sodium fluoroscopy device can be extended to cover the entire core structure, expanding the range of use to the field of core inspection equipment that can observe the inside of the reactor from a macroscopic perspective, and the value of its use is increasing. It gets expensive.

Furthermore, since the transducer arrangement is simple, transducer positions and signals can be matched well, and signal processing becomes easier.

[Brief explanation of drawings]

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

Claims (1)

[Claims] 1 A rotating housing that hangs down from a rotating plug that covers the top of the fast breeder reactor, a scanning guide that is rotatably attached to the lower part of the rotating housing with one end via a shaft, and a horizontal movement guided by this scanning guide. A transducer holder provided freely, a large number of transducers attached to the transducer holder at predetermined intervals, a signal cable attached to the transducer, and a signal cable provided near the rotation axis of the scanning guide. and a cable guide for guiding a signal cable at a predetermined bending radius, the scanning guide having a rotating shaft disposed above an upper surface of the scanning guide.