JP2002286891A - Canister for storing spent nuclear fuel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a canister for storing spent nuclear fuel, having high radiation efficiency and capable of storing nuclear fuel with high heating rate. SOLUTION: A basket 20, installed in a reactor containment 11 and constituting a canister, is supported in layer at spacer plates 21 with support rods 22 and is constituted by providing a heat conduction plate 25, formed with aluminum plates along each of the spacer plates 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a canister for storing spent nuclear fuel for storing spent nuclear fuel until reprocessing.

[0002]

2. Description of the Related Art Spent nuclear fuel used in a nuclear power plant must be stored while shielding radiation and dissipating decay heat until reprocessing. As shown in FIG. 5, a canister 10 ′ containing a spent nuclear fuel assembly (fuel rod) can be stored in a concrete cask 50 by storing such a canister 10 ′.
It is conceived that it is stored and carried out.

[0003] The canister 10 'is a cylindrical storage container 1.
1 ', a basket formed by laminating a mesh-like spacer plate as a support member having a plurality of support holes is inserted therein, and a guide tube extending in the axial direction is held in the support hole of the basket. The tube is configured to contain spent nuclear fuel rods. Heat released from the stored spent nuclear fuel is transmitted from the guide tube to the storage container via the spacer plate (basket), and is released from the outer surface of the storage container 11 'to the outside.

[0004] A concrete cask 50 houses a canister 10 ′ inside a main body container 51 formed in a cylindrical shape with a bottom by concrete of a predetermined thickness, and an upper opening is hermetically closed by a closing lid 52. ing.

[0005] The main container 51 has a canister 1 in the center.
A cylindrical storage space 5 having an inner diameter larger than the outer diameter of 0 'by a predetermined amount.
1A, a cooling air discharge passage 51B communicating the storage space 51A with the outside near the upper portion, and a cooling air supply passage 51 communicating the lower portion of the storage space 51A with the outside at the bottom.
C are provided, and an annular cooling space 51D formed around the canister 10 'housed in the storage space 51A is provided with a cooling air discharge 51B passage and a cooling air supply passage 5.
It communicates with the outside via 1C.

In the concrete cask 50 constructed as described above, the air in the cooling space 51D heated by the heat released from the canister 10 'to be stored is discharged to the outside from the cooling air discharge passage 51B and cooled from the outside. Air is supplied to the cooling space 51D via the air supply passage 51C, and the canister 10 'is cooled by air flowing naturally through the cooling air supply passage 51C, the cooling space 51D, and the cooling air discharge passage 51B (naturally). Air cooling)
Things.

[0007]

Recently, high burn-up fuels have been used to reduce the amount of spent nuclear fuel.

However, since the high burn-up fuel has a high calorific value, a canister that is thermally designed based on the conventional calorific value nuclear fuel may be heated to a temperature higher than a set temperature. In the case of storage, there is a problem that the canister must have high heat radiation efficiency.

The present invention has been made in view of the above problems, and has as its object to provide a canister for storing spent nuclear fuel which has high heat radiation efficiency and can store nuclear fuel having a high calorific value. I do.

[0010]

A canister for storing spent nuclear fuel according to the present invention, which achieves the above object, has a basket in which support members each having a support hole are stacked and arranged in a storage container. In a spent nuclear fuel storage canister supporting a spent nuclear fuel by a support member, a heat conductive member formed of a material having a high thermal conductivity such as an aluminum plate is superposed and arranged on the support member. Features.

[0011]

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

FIG. 1 is an exploded perspective view of a configuration example of a canister for storing spent nuclear fuel according to the present invention.

In the illustrated canister 10, a basket 20 holding a guide tube 12 is inserted in a cylindrical storage container 11 having a bottom, and a spent nuclear fuel rod (not shown) is accommodated in the guide tube 12. A lower shielding plug 13 is provided at a lower part of the storage container 11, and an upper shielding plug 14 is provided at an upper part. The upper opening is closed and sealed by a primary sealing lid 15 and a secondary sealing lid 16, and the whole is cylindrical. It shows.

As shown in a partial front view of FIG. 2, a plurality of spacer plates 21 (connector spacer plates 21A and intermediate spacer plates 21B) as support members extend in the longitudinal direction of the basket 20. The support rods 22 are stacked and supported at predetermined intervals, and have a columnar shape as a whole.

3, the support rod 22 is divided into unit rods 22A of a predetermined length in the longitudinal direction, as shown in FIG.
A connecting male screw 22a protruding from the end of 2A is screwed into a connecting female screw 22b formed at the end of the other unit rod 22A to be connected and integrated, and is connected to the connecting portion (between both support rods 22A). The connecting portion spacer plate 21A and the washer 23 are interposed and fixed (therefore, the connecting portion spacer plate 21A is disposed at an interval obtained by adding the thickness of the washer 23 to the length of the unit rod 22A), and these connecting portion spacers are also provided. A plurality of intermediate spacer plates 21B are arranged at predetermined intervals between the plates 21A.

As shown in a plan view in FIG. 4, the spacer plate 21 is formed of a steel plate having a predetermined thickness in a disk shape to be fitted in the storage container 11, and a plurality of rectangular support holes 21a are formed in the vertical and horizontal directions. At the same time, a mounting hole 21b is provided in the peripheral portion, and the support rod 2
2 supported. Connection part spacer plate 21A
The intermediate spacer plate 21B differs from the intermediate spacer plate 21B only in the diameter of the mounting hole 21b. That is, the mounting hole 21b of the connecting portion spacer plate 21A has a diameter through which the connecting male screw 22a of the unit rod 22A can fit and penetrate, and the mounting hole 21b of the intermediate spacer plate 21B is formed of the unit rod 22A.
The diameter is set so that the (support rod 22) can fit and penetrate.

The connecting portion spacer plate 21A is interposed and fixed to the connecting portion of the unit rod 22A as described above, and the intermediate portion spacer plate 21B is connected to the support rod 22 (unit rod 22
A) is alternately extrapolated to the support sleeve 24 and is immovably provided at the interval of the support sleeve 24. However, only the intermediate spacer plate 21B immediately below the connecting spacer plate 21A is sandwiched between the washer 23 and the support sleeve 24 as shown in FIG.

Here, each intermediate part spacer plate 21
In B, a heat conductive plate 25 as a heat conductive member is provided along one surface side.

The heat conductive plate 25 is formed of an aluminum plate having a predetermined thickness in a plane shape corresponding to the intermediate spacer plate 21B, and has a diameter at which the support sleeve 24 can be inserted at a position corresponding to the mounting hole 21b. Mounting hole 2
5a are formed.

Such a heat conducting plate 25 is located above the intermediate spacer plate 21B, and is disposed in close contact with the upper surface of the intermediate spacer plate 21B by an outer support sleeve 27 inserted outside the support sleeve 24. ing.

The connecting spacer plate 21A provided at the connecting portion of the unit rod 22a and the intermediate spacer plate 21B located below the washer 23.
The heat conductive plate 25 located on the upper side of the upper surface of the connecting portion spacer plate 21A and the intermediate portion spacer plate 21B
And the upper surface of the In other words, washer 2
3 and the heat conducting plate 25 are set to have the same thickness.

In the canister 10 having the basket 20 configured as described above, the heat released from the stored spent nuclear fuel is quickly conducted to the containment vessel 11 by the heat conducting plate 25, thereby improving the heat radiation efficiency and increasing the temperature. Can be suppressed.

Further, since the heat conductive plate 25 is only provided along the intermediate spacer plate 21B by the outer support sleeve 27, it does not affect the strength of the support rod 21 and the spacer plate 21 which are structural materials. Therefore, the heat radiation efficiency can be improved only by adding the heat conducting plate 25 to the canister thermally designed based on the conventional calorific value of nuclear fuel. For example, in the case where an aluminum plate having a thickness of 10 mm is provided on each spacer plate of a canister having an outer diameter of 1.7 m and a height of 4.9 m, the internal temperature can be reduced by about 40 to 50 ° C.

Incidentally, the arrangement structure of the heat conducting plate is not limited to the above configuration example, but can be changed as appropriate. Further, the material of the heat conductive plate is not limited to aluminum as long as it has high heat conductivity, and is applicable.

[0025]

As described above, according to the canister for storing spent nuclear fuel according to the present invention, a heat conducting member formed of a material having a high heat conductivity such as an aluminum plate is provided on a supporting member. By being configured
The heat conduction member can quickly transfer the heat released from the stored spent nuclear fuel to the storage container and obtain high heat dissipation efficiency, so that it is possible to suppress a rise in temperature and to store a high calorific value nuclear fuel. Things.

In addition, the heat radiation efficiency can be increased without deteriorating the structural strength only by arranging the heat conducting member on the support member of the canister set for the low calorific value nuclear fuel. It can also be applied to storage of nuclear fuel.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a configuration example of a canister for storing spent nuclear fuel according to the present invention.

FIG. 2 is a partial front view of a basket.

FIG. 3 is an enlarged sectional view of a part X in FIG. 2;

FIG. 4 is a plan view of a spacer plate.

FIG. 5 is a longitudinal sectional view of a concrete cask.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Canister 11 Containment container 20 Basket 21 Spacer plate (support member) 21a Support hole 25 Heat conductive plate (heat conductive member)

Claims (2)

[Claims] 1. A canister for storing spent nuclear fuel, wherein a basket in which support members each having a support hole are stacked and disposed is disposed in a storage container, and wherein the support member supports spent nuclear fuel. A canister for storing spent nuclear fuel, wherein a heat conducting member formed of a material having a high heat conductivity is superposed and arranged. 2. The canister for storing spent nuclear fuel according to claim 1, wherein the heat conducting member is an aluminum plate.