JP2002328198A - Glass melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To head melted glass at a furnace bottom part to a prescribed temperature without being influenced by platinum group elements. SOLUTION: This glass melting furnace is provided with a melting furnace body 2 with a melting space 1 formed inside; a glass takeoff port 10 provided at the furnace bottom part 4 of the melting furnace body 2; main electrodes 3 provided at the intermediate part of the melting space 1; and a bottom electrode 5 provided at the furnace bottom part 4. An electrode rod 12 for high frequency induction heating is provided in the melting space 1 directly above the furnace bottom part 4, and a high frequency current is applied to the electrode rod 12 to heat the molten glass G to the prescribed temperature or higher by induction heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a glass melting furnace used for vitrifying highly radioactive liquid waste.

[0002]

2. Description of the Related Art Highly radioactive liquid waste generated in nuclear facilities is melted by a glass melting furnace of a highly radioactive liquid waste vitrification facility, treated as vitrified material, and stored in a radioactive waste storage facility.

[0003] In the above-mentioned vitrification facility, highly radioactive waste liquid is mixed when raw glass is melted inside a glass melting furnace, and the molten glass mixed with this highly radioactive waste liquid is poured into a solidification vessel, and the molten glass is melted. By solidifying,
A vitrified body is formed.

FIG. 3 is a vertical sectional front view showing an example of a conventional glass melting furnace, and FIG. 4 is a vertical sectional side view of FIG.
In the figure, reference numeral 2 denotes a melting furnace main body, and the melting furnace main body 2 is made of a corrosion-resistant refractory brick 2a so as to form a melting space 1 therein.

[0005] Main electrodes 3 are provided on the left and right sides of the upper and lower middle portions of the melting furnace body 2 so as to face each other.
A bottom electrode 5 is provided on the narrowed furnace bottom 4 below the melting space 1, and an inner end of the bottom electrode 5 projects into the melting space 1. 3 and 4, reference numeral 6 denotes a raw material supply port provided on the upper portion of the melting furnace main body 2 for supplying raw glass, highly radioactive waste liquid, etc., 7 denotes a waste gas outlet pipe, 8 denotes a waste gas treatment device, and 9 denotes a waste gas treatment device. Auxiliary electrodes 10 are glass outlets formed on the furnace bottom 4 for taking out molten glass,
11 is a heater for heating the glass outlet 10, and G is molten glass.

[0006] It is known that a very small amount of platinum group elements such as ruthenium (Ru), rhodium (Rh) and palladium (Pd) are mixed in the highly radioactive waste liquid supplied to the glass melting furnace. Platinum group elements are used in the production of fuel rods for nuclear reactors due to their high temperature resistance and excellent ductility.
Therefore, platinum group elements are mixed in the highly radioactive waste liquid obtained by cutting and melting the spent fuel rod.

[0007]

In order to melt the glass in the melting furnace main body 2, a current is applied between the opposing main electrodes 3 to melt the glass by Joule heat. However, when the highly radioactive waste liquid is mixed with the glass inside the melting furnace body 2 and melted, the platinum group element contained in the highly radioactive waste liquid is not taken into the molten glass G and settles down in the melting furnace body 2 and It tends to deposit near the bottom 4.

On the other hand, the molten glass is supplied to the glass outlet 1
In order to cause the temperature to fall from zero, a current is applied between the main electrode 3 and the bottom electrode 5 to heat the glass temperature of the furnace bottom 4 to a predetermined temperature or higher. However, a platinum group element is deposited on the furnace bottom. Then, since the platinum group element has conductivity, the current from the main electrode 3 flows through the platinum group element and does not generate heat, so that the glass temperature of the furnace bottom 4 does not rise to a predetermined temperature. However, there is a problem that the removal of the molten glass G is hindered.

The present invention has been made to solve the above problems and to provide a glass melting furnace capable of heating a molten glass at a furnace bottom to a predetermined temperature without being affected by a platinum group element. It is the purpose.

[0010]

In order to achieve the above object, the present invention provides a melting furnace body having a melting space formed therein, a glass outlet provided at a furnace bottom of the melting furnace body, and the melting space. In a glass melting furnace provided with a main electrode provided in the middle of the, and a bottom electrode provided in the furnace bottom,
An object of the present invention is to provide a glass melting furnace, wherein an electrode rod for high-frequency induction heating is provided in a melting space just above the furnace bottom.

In the above-mentioned glass melting furnace, the vicinity of the furnace bottom is subjected to high-frequency induction heating by applying a high-frequency current to an electrode rod for high-frequency induction heating, and the glass at the bottom of the furnace is heated to a predetermined temperature, and the platinum group element is also mixed with the glass. It can flow down from the outlet.

[0012]

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

FIG. 1 is a longitudinal sectional front view showing an example of an embodiment of the present invention, and FIG. 2 is a plan view of FIG. 1. In FIG. 1, the same parts as those in FIGS.

As shown in FIGS. 1 and 2, in the glass melting furnace of the present invention, an electrode for high frequency induction heating A bar 12 is provided. Electrode rod 12 for high frequency induction heating
May be one or more, and the cross-sectional shape may be any of a hollow cylindrical center, a solid circle, and a square.

Next, the operation of the present invention will be described.

When electricity is supplied between the main electrode 3 and the bottom electrode 5 to raise the molten glass G particularly at the furnace bottom 4 to a predetermined temperature, and the molten glass G flows down from the glass outlet 10 and is taken out, When a high-frequency current is applied to the electrode rod 12 at the same time,
The molten glass G containing the platinum group element 13 deposited near the furnace bottom 4 is heated by the high-frequency induction heating of the current flowing through the electrode rod 12 and keeps a flowing state. It flows down from the outlet 10 and is taken out.

[0017]

According to the present invention, the high-frequency induction heating of the current flowing through the electrode rod effectively heats the molten glass containing the platinum group element to be deposited near the bottom of the furnace and keeps the molten glass in a fluid state. Has the effect that it can be taken out of the glass outlet together with the molten glass without being deposited.

[Brief description of the drawings]

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

FIG. 2 is a plan view of FIG.

FIG. 3 is a vertical sectional front view showing an example of a conventional glass melting furnace.

FIG. 4 is a vertical sectional side view of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Melting space 2 Melting furnace main body 3 Main electrode 4 Furnace bottom 5 Bottom electrode 10 Glass outlet 12 Electrode rod

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Claims (1)

[Claims] 1. A melting furnace body having a melting space formed therein, a glass outlet provided at a furnace bottom of the melting furnace body, a main electrode provided at an intermediate portion of the melting space, A glass melting furnace comprising: a bottom electrode provided at a bottom; and a high frequency induction heating electrode rod provided in a melting space immediately above the furnace bottom.