JPH0762719B2 - Glass melting furnace - Google Patents

Description

TECHNICAL FIELD The present invention relates to a glass melting furnace for melting and mixing a radioactive liquid waste and a glass material into a container, and particularly to forcibly stopping the filling. It relates to a glass melting furnace.

“Conventional technology and its problems” Generally, high-level radioactive liquid waste generated in nuclear power generation facilities is melted and mixed with glass materials in a glass melting furnace.
A so-called vitrification treatment for filling and solidifying the melted mixture in another prepared container is attempted.

In this case, since the melted mixture has a viscosity like a starch syrup, a reliable stopping means for surely stopping the filling of the molten mixture is required. It is necessary to make sure that there is no intrusion of the radiation, and to manage the filling amount delicately to prevent the overflow that would lead to scattering of the radiation source.

"Object of the present invention and means for achieving the same" The present invention has been proposed in view of the above circumstances, and has an object to stop the filling of the molten mixture quickly and reliably to prevent the occurrence of overflow. In order to achieve such a purpose, in a glass melting furnace in which a molten mixture obtained by melting and mixing a radioactive waste liquid and a glass material is made to flow from a hole in the lower part of a nozzle to fill a container, in the vicinity of the nozzle,
A shutter for opening and closing the hole of the nozzle is provided, and the shutter has a drive mechanism for swinging the arm in a vertical plane,
A lid attached to the tip of the arm for closing the nozzle hole by contacting it from below, and a filling amount detection device for detecting the filling amount in the container is provided near the installation position of the container, and Between the filling amount detection device and the drive mechanism,
A configuration is adopted in which a control device that outputs a control signal for closing the nozzle hole is connected in series according to the detection result of the filling amount detection device.

[Operation] By adopting such a configuration, the molten mixture is made to flow down through the hole in the lower portion of the nozzle to fill the container. When the molten mixture is flowed down, the lid of the shutter is swung downward. When the filling amount detection device detects a predetermined filling amount by avoiding interference with the molten mixture flowing down by waiting at a position separated from the lower part of the nozzle, the drive mechanism is operated to cover the end of the arm. The flow of the molten mixture is forcibly stopped by contacting and closing the nozzle hole from below.

Example An example of the glass melting furnace of the present invention will be described below with reference to the drawings.

This glass melting furnace is installed in a cell 1 for shielding radiation, and a plurality of electrodes 3 for energizing a melted object of a radioactive waste liquid and a glass material are provided on both side walls and a bottom wall 2a of a tank 2. And a nozzle 5 provided with a heating device 4 such as a high frequency coil is provided on the lower surface of the bottom wall portion 2a, and the hole 5a thereof communicates with the space in the tank 1. In addition, a cylindrical jacket 6 is provided on the outer bottom of the tank 1 so as to surround the nozzle 5 at intervals, and the lower end of the jacket 6 is filled with the molten mixture G flowing down from the nozzle 5. A coupling device 8 detachably connected to the mouth of the container 7 is provided, and inside the jacket 6,
A cooling header (not shown) for injecting cooling air toward the nozzle 5 is provided.

A shutter 9 capable of opening and closing the hole 5a is provided near the lower end of the nozzle 5 while being supported by the inner wall of the jacket 6. The shutter 9 has an arm 11 fixed to a rotary shaft 10a horizontally arranged in a drive mechanism 10 so that the shutter 9 can be swung in a vertical plane, and the tip of the arm 11 has a broken line in FIG. When the arm 11 is in a horizontal state as shown in FIG. 2, the lid 12 that abuts the lower end of the nozzle 5 to close the hole 5a
Is provided. The drive mechanism 10 is composed of a rotary actuator or the like, and is provided with an air supply pipe 13 for sending pressurized air for driving the rotating shaft 10a, and a valve 14 for opening and closing the flow path thereof.

On the other hand, in the vicinity of the position where the container 7 is installed, a plurality of thermocouples 15 that are brought into contact with the outer peripheral portion of the container 7 are provided at intervals in the vertical direction. These thermocouples 15 measure the temperature change of the wall of the container 7 due to the filling of the molten mixture G in the container 7, and between the second and third thermocouples 15 from the top of FIG. The reference range of the filling amount is set to, and the uppermost thermocouple 15 is for detecting an abnormality when the filling is not stopped even when the reference range is exceeded. Then, to these thermocouples 15, a determination circuit 16 for determining which thermocouple 15 the liquid surface is located on is based on the measurement data, and the determination circuit 16 is provided in series.
Is configured.

Further, outside the cell 1, there is provided a control device 18 that displays the liquid level according to the detection result of the filling amount detection device 17 and controls the stop of filling. When the filling amount detection device 17 detects that the filling amount has reached the reference range, the control device 18 outputs a control signal to turn off the heating device 4 and send cooling air to the cooling header. In addition, when it is detected that the position of the uppermost thermocouple 15 is reached, an abnormal control signal is output, an alarm is issued, and the valve 14 of the air supply pipe 13 is controlled to open. It is designed to do.

In the glass melting furnace configured as described above, in the case of normal filling control, when the filling amount reaches within the reference range, the control device 18 controls the heating device 4 to be turned off and the cooling air from the cooling header. The flow is stopped by a freeze valve system in which the molten mixture G is fed and cooled and solidified in the hole 5a of the nozzle 5. Further, when it is detected that the molten mixture G has not stopped flowing down due to occurrence of a failure and the liquid level has reached the position of the uppermost thermocouple 15 beyond the reference range, the control device 18 outputs an abnormal control signal. To drive the valve 14 in the opening direction to send pressurized air from the air supply pipe 13 to the drive mechanism 10 of the shutter 9 to rotate the arm 11 as shown by the arrow in FIG. Cover the hole 5a of the nozzle 5
By closing at 12, the flow is forcibly blocked.

That is, this glass melting furnace is provided with a double stop means for stopping the filling at the normal time by the freeze valve system and forcibly stopping at the time of an abnormal condition by the shutter 9 to have high reliability and to set the stop time of these. It is possible to perform remote control while confirming by the control device 18 outside the cell 1 shielded from radiation. The drive mechanism of the shutter 9
Since 10 is composed of a rotary actuator or the like that is operated by pressurized air, the occurrence of failures in a radiation environment can be reduced and maintenance can be facilitated.

"Effects of the Invention" As described above, according to the glass melting furnace of the present invention,
Since the hole of the nozzle is closed by the shutter to forcibly stop the flow-down, the flow-down can be stopped promptly and reliably without being affected by the viscosity of the molten mixture, etc., and the occurrence of overflow, etc. can be prevented. Further, the stop of the filling can be remotely controlled by the control device on the basis of the detection result of the filling amount detection device, and there is an effect that the melting work can be efficiently performed in the radiation environment.
In addition, when the molten mixture flows down, the lid of the shutter is swung downward so as to stand by at a position separated from the lower side of the nozzle, so that in the normal case, the shutter interferes with the molten mixture flowing down. Therefore, it is possible to prevent the molten mixture from adhering to improve the maintainability and reduce the occurrence of failures.

[Brief description of drawings]

FIG. 1 is a front sectional view with a part omitted showing an embodiment of a glass melting furnace of the present invention, and FIG. 2 is a sectional view taken along the line II-II of FIG. 1 ... cell, 2 ... tank, 3 ... electrode, 4 ... heating device,
5 ... Nozzle, 5a ... Hole, 6 ... Jacket, 7 ... Container, 8 ... Coupling device, 9 ... Shutter, 10 ... Drive mechanism, 10a ... Rotation axis, 11 ... Arm, 12 ... … Lid, 13 ……
Air supply pipe, 14 ... Valve, 15 ... Thermocouple, 16 ... Judgment circuit, 17 ... Filling amount detection device, 18 ... Control device, G ... Molten mixture.

Claims (1)

[Claims] 1. A glass melting furnace for filling a container (7) with a molten mixture obtained by melting and mixing a radioactive waste liquid and a glass material through a hole (5a) in the lower part of the nozzle (5) and in the vicinity of the nozzle. , A shutter (9) for opening and closing the hole of the nozzle is provided, and the shutter includes a drive mechanism (10) for swinging the arm (11) in a vertical plane and a nozzle hole attached to the tip of the arm. A filling amount detecting device (17) for detecting the filling amount in the container is provided near the installation position of the container, and has a lid (12) that comes into contact with and closes from below, and the filling amount detecting device and the above-mentioned device. A glass melting furnace characterized in that a control device (18) for outputting a control signal for closing a hole of a nozzle is connected in series with a drive mechanism according to a detection result of a filling amount detection device.