JPH0430559Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a basket for a spent nuclear fuel melting device used in the melting process of spent nuclear fuel reprocessing.

(Prior art) As shown in Figure 7, the spent nuclear fuel melting device
A dissolution tank 2 is connected to the central liquid storage tank 1 through a solution distribution pipe 3 and a gas phase communication pipe 4, a basket 5 is attached to the dissolution tank 2, and the spent nuclear fuel fragments 6 are stored in the basket 5. . Further, a jacket 7 is provided around the outer periphery of the dissolving tank 2. As shown in FIGS. 4 to 6, the conventional basket 5 has a width of about 13
Round openings 8 with a diameter of about 3 mm were bored and arranged in a square pattern with a pitch of mm.

When processing the fragments 6, nitric acid solution is injected into the tanks 1 and 2 to the required level, high temperature steam is passed through the jacket 7 provided in the dissolving tank 2, and the nitric acid solution is heated as shown by arrow A. The spent nuclear fuel contained in the fragments 6 was melted by flowing the fuel in this way.

(Problems to be solved by the invention) In the basket 5 shown in FIGS. 4 to 6, the aperture ratio of the openings 8 is 4 to 4.4%, and the fluidity of the nitric acid solution is poor, especially around the outer periphery of the nuclear fuel cladding. There was a problem in that the wrapped wrapping wire having an outer diameter of 0.9 mm would flow out from the opening 8 when the nuclear fuel was melted.

(Means for Solving the Problems) The present invention addresses the above-mentioned problems, and includes a spent nuclear fuel melting device that has a central storage tank and a melting tank connected to the storage tank. The basket for a spent nuclear fuel melting device is characterized in that the outer surface of the basket for storing nuclear fuel fragments is formed by a wedge wire screen, and its purpose is to increase the aperture ratio, It is an object of the present invention to provide a basket for a spent nuclear fuel melting device that can increase the fluidity of a nitric acid solution and further prevent wrapping wires from passing through an opening.

(Function) In the present invention, since the wedge wire screen constituting the outer surface of the basket has a large aperture ratio, the fluidity of the nitric acid solution in the dissolution tank is improved, and the width of the interval between the wedge wires constituting the screen is reduced. The outer diameter of the wrapping wire is smaller than the outer diameter of the wrapping wire, which prevents the wrapping wire from passing through the openings in the wedge wire screen, and the vertical orientation of the wedge wire in the screen prevents the wrapping wire from passing through the openings in the wedge wire screen. ) to prevent it from getting caught when putting it in and taking it out.

(Example) A basket for a spent nuclear fuel melting device according to the present invention will be explained with reference to FIGS. 1 to 3.

The side wall of the basket 11 is formed by a wedge wire screen 14 composed of a vertical member 12 having a triangular cross section and a horizontal member 13 connecting the outer corners of the vertical member 12 in a ring shape with a rough pitch. is formed by a wedge wire screen 14 formed by a vertical member 12 having a triangular cross section and a horizontal member 13 connecting the lower corners of the vertical member 12 with a rough pitch.

Since the illustrated embodiment is configured as described above, for example, the width W of the vertical member 12 is 3 mm, and the vertical member 1 is
If the gap S between the two is 0.5 mm, then the basket 11
The aperture ratio is approximately 14%, which is more than three times the aperture ratio of the conventional basket 5 shown in FIGS. 4 to 6. Therefore, the fluidity of the nitric acid solution in the dissolution tank 2 shown in FIG. 7 is greatly improved. Further, since the gap between the vertical members 12 is 0.5 mm, the wrapping wire having an outer diameter of about 0.9 mm will not flow out. Furthermore, a wedge wire screen 14 on the side wall of the basket 11
Since the vertical members are arranged in the vertical direction, the stored items do not get caught in the basket 11 when the items stored in the basket 11 are put in and taken out.

(Effects of the invention) As described above, in the present invention, the basket is constructed of a wedge wire screen with a large opening ratio, so the fluidity of the nitric acid solution flowing through the dissolution tank and the storage tank can be improved. The gap between the screens is sufficiently small to prevent the wrapping wire from flowing out of the basket, and the vertical members of the wedge wire screen on the side walls of the basket are arranged vertically, making it easy to remove items from the basket. This has the effect of preventing the basket from getting caught.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional side view of the basket for a spent nuclear fuel melting device of the present invention, Fig. 2 is a cross-sectional B view of Fig. 1, Fig. 3 is an enlarged view of part C in Fig. 1, and Fig. 4 is a conventional 5 is a cross-sectional plan view of FIG. 4, FIG. 6 is an enlarged view of section D in FIG. 4, and FIG. 7 is a cross-sectional side view of the spent nuclear fuel melting device. 1...Storage tank, 2...Dissolution tank, 6...Nuclear fuel fragments, 11...Basket, 14...Wedge wire screen.

Claims (1)

[Scope of utility model registration request] In a spent nuclear fuel melting device having a central storage tank and a melting tank connected to the storage tank, the outer surface of the basket disposed in the melting tank and containing nuclear fuel fragments is formed with a wedge wire screen. A basket for a spent nuclear fuel melting device characterized by: