JPH0216319Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to spent nuclear fuel storage equipment.

During periodic inspections of nuclear power plants, spent nuclear fuel assemblies removed from the reactor are temporarily stored in a lux cell installed in a pit adjacent to the reactor containment vessel, and then removed from the pit. After being cooled by the water inside for a certain period of time, it is transported to a reprocessing plant.

An example of a conventional spent nuclear fuel storage facility is shown in FIG.
2 is an embedded board 05 attached to the wall 04 of the pit
It was attached and fixed with welding 09. Reference numeral 03 indicates an embedded metal fitting for supporting and fixing the embedded plate 05 to the wall 04 of the pit, and 08 indicates a column for supporting the rack support plate 02.

The spent nuclear fuel taken out from the reactor has some residual heat, so when this spent nuclear fuel is stored in the rack cell 01, the rack cell 01 and the rack support plate 02 are heated by the spent nuclear fuel and emit heat. However, since the embedded plate 05 is fixed to the wall 04 of the pit via the embedded metal fittings 03, the rack support plate 02 and the embedded plate 05 are subjected to thermal stress due to the difference in thermal expansion. Therefore, it was necessary to increase the strength of the rack support plate 02 and the embedded plate 05.

The present invention was proposed to address the above problem, and its gist is that it includes a pit for storing cooling water, and a plurality of pits arranged vertically within the pit for storing spent nuclear fuel. In a spent nuclear fuel storage facility equipped with a cylindrical rack cell and two rack support plates arranged approximately horizontally, one above the other, which connect and support the rack cell, the rack support plate is provided around the rack support plate to control the flow of cooling water. a sliding member formed on the outer periphery of the rack support plate parallel to the pit wall and fixed at both ends by the rack support plate; and a sliding member fixed to the pit wall that allows the sliding member to move vertically and horizontally. and a relative displacement absorbing joint that movably surrounds and supports the spent nuclear fuel.

Since the present invention has the above configuration,
Even if the rack support plate is heated and thermally expanded when spent nuclear fuel taken out from the reactor is stored in the rack cell, the rack support plate is attached to the pit wall via a relative displacement absorbing joint. Because of this, the rack support plate can be displaced relative to the pit wall. Therefore, unlike the conventional case, thermal stress is not applied to the rack support plate, so there is no risk of the rack support plate being damaged, and its strength can be reduced, so it can be manufactured at low cost.

Hereinafter, the present invention will be explained in detail with reference to an embodiment shown in FIGS. 2 to 4.

Figure 2 is a partial plan view, Figure 3 is the -
FIG. 4 is a perspective view showing the relative displacement absorbing joint.

In Figures 2 to 4, 1 is a rack cell that can receive spent nuclear fuel, and 2 is a rack support plate that supports the rack cell 1. Although not shown, the rack support plate is fixed to a plurality of supports like a conventional rack support plate. They are arranged horizontally in two stages, upper and lower, in a pit in which cooling water is stored. Reference numeral 5 denotes an embedded plate which is attached to the pit wall 4 via an embedded metal fitting 3 embedded in the pit wall 4. By cutting the rack support plate 2 near the pit wall 4 into a rectangular shape, a U-shaped cross section is formed on the pier portion 2a extending parallel to the pit wall 4, which is formed between the notch 8 and the edge. The holder 6 is fitted, and a holder adapter 6a is welded to the open end of the holder to form a sheath shape to grip the pier portion 2a. A fixing metal fitting 7 is welded to the upper surface of the holder 6, and this fixing metal fitting 7 is welded and fixed to the embedded plate 5. The dimension a indicates the horizontal thermal expansion absorption along the edge of the rack support plate 2, and the dimension b indicates the vertical thermal expansion absorption.
Thus, the rack support plate 2 is attached to the pit wall 4 via the relative displacement absorbing joint 10 consisting of the pier portion 2a, the holder 6, the holder adapter 6a, the fixing fittings 7, the embedded plate 5, and the embedded metal fittings 3.

FIG. 5 is a plan view showing an example in which the present invention is applied to a spent nuclear fuel storage facility equipped with a rack support plate 2 divided into four parts. It is necessary to have a size sufficient to absorb thermal expansion in step 2.

FIG. 6 shows an enlarged view of one of the divided rack support plates 2 in FIG. It is equipped with an absorption joint 10, and the thermal elongation of the rack support plate 2 in the P arrow direction is absorbed by the relative displacement absorption joint 10 attached to the side B, and the thermal elongation of the rack support plate 2 in the Q arrow direction is absorbed by the relative displacement absorption joint 10 attached to the side A. The relative displacement is absorbed by the relative displacement absorbing joint 10. Furthermore, even in the event of an earthquake, the relative displacement absorption joint 10 attached to side B absorbs the shaking in the P arrow direction, and the relative displacement absorption joint 10 attached to side A absorbs the shaking in the Q arrow direction. do.

FIG. 7 is a plan view showing an example in which the present invention is applied to a large-capacity spent nuclear fuel storage facility.The rack support plate 2 has a limited size due to convenience in construction and transportation. This is 8 rack support plates 2
It is equipped with Adjacent rack support plates 2 can be connected to each other using joints 11 or by direct welding to form four rack support plates.

FIG. 8 is a perspective view showing another example of a relative displacement absorbing joint, in which the sliding rod 12 is inserted parallel to the edge of the rack support plate 2 at a predetermined distance from the edge.
This sliding rod 13 is fitted into the holder 6. The sliding rod 12 is not limited to flat steel, but can also be a square bar, round pipe, etc., and the passing rod is not limited to flat steel, but can also be made of angle-shaped steel, square bar, round pipe, or other steel materials. can.

Thus, when spent nuclear fuel taken out from a nuclear reactor is stored in rack cell 1, when rack cell 1 and rack support plate 2 thermally expand, the horizontal thermal expansion of rack support plate 2 is equal to the relative displacement absorbing joint 10.
It can be absorbed by the horizontal thermal expansion absorption allowance a, and the vertical thermal expansion can be absorbed by the vertical thermal expansion absorption allowance b of the relative displacement absorbing joint 10. In addition, Luxel 1
Even if the rack support plate 2 is inserted into the hole drilled in the rack support plate 2 without welding it to the rack support plate 2, the rack support plate 2 will be lifted by the amount of thermal expansion of the support column, so in this case, it corresponds to the amount of thermal expansion of the support column. It is necessary to provide an allowance for thermal expansion absorption in the vertical direction.

As mentioned above, since the horizontal and vertical displacements of the rack support plate can be absorbed by the relative displacement absorbing joint 10, stress does not act on the rack support plate and the embedded plate as in the conventional case. Since these strengths can be reduced, manufacturing can be done at low cost.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of an example of a conventional spent nuclear fuel storage facility, Figs. 2 to 4 show an embodiment of the present invention, and Fig. 2 is a partial plan view. Figure 3 is a sectional view taken along the - line in Figure 2, Figure 4 is a perspective view showing a relative displacement absorption joint, and Figure 5 is a spent nuclear fuel storage facility equipped with a rack support plate divided into four parts. FIG. 6 is a plan view showing an enlarged view of one of the divided rack support plates in FIG. 5, and FIG. 7 is a large-capacity spent nuclear fuel storage facility. FIG. 8 is a plan view showing an example to which the present invention is applied, and FIG. 8 is a perspective view showing another example of the relative displacement absorbing joint. Rack cell...1, Rack support plate...2, Pit wall...4, Support column...8, Relative displacement absorption joint...
10.

Claims (1)

[Scope of utility model registration request] A pit for storing cooling water, a plurality of cylindrical rack cells arranged vertically in the pit for storing spent nuclear fuel, and two rack support plates arranged approximately horizontally, upper and lower, that connect and support the rack cells. A spent nuclear fuel storage facility comprising: a notch provided around the rack support plate to allow the flow of cooling water; and a notch formed on the outer periphery of the rack support plate parallel to the pit wall A spent nuclear fuel system comprising a sliding member fixed at both ends by plates, and a relative displacement absorbing joint fixed to a pit wall and surrounding and supporting the sliding member so as to be movable in the vertical and horizontal directions. Storage equipment.