JPS6093377A - Fuel aggregate for nuclear reactor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rod-shaped nuclear reactor fuel assembly which has a regular polygonal cross section and is closely assembled in a U shape to form a nuclear reactor core. (The combination of the spherical guide structure and rounded keys allows
This relates to a nuclear reactor fuel assembly that has a self-orientation adjustment function during fuel exchange.

In general, the core of a fast breeder reactor consists of a number of fuel assemblies with a regular hexagonal cross section and other core components (such as control rods and neutron shields) closely spaced together. Hundreds of them are often arranged in an equilateral triangular grid.

Therefore, when one spent fuel assembly is pulled out from the core,
A hexagonal column-shaped hole surrounded by six peripheral fuel assemblies will be created there. Even if a new fuel assembly is inserted into this hexagonal hole and lowered from the upper part of the core, the refueling machine normally lowers the fuel assembly to the top. Since it is not possible to change the direction of the holes, the direction of the holes and the direction of the new fuel assembly do not necessarily match. If they match, they can be inserted as is, but if they are misaligned, they cannot be inserted.

Hi, conventionally, in fuel assemblies, the direction of the holes and the direction of the new fuel assembly inserted into them do not match very well.
1, the new fuel assembly automatically rotates according to the direction of the hole, and self-orients itself in some way to face the appropriate direction. A mechanism is built in.

A typical example is, for example, Tokuko Sho 48-175!
J: sea urchin seen in Publication No.
and a vertical key (protrusion) that matches the extension line of the ridge of the vertical cross section, and the handling head is provided with a V-shaped slope at the end of each side of the fuel assembly, The key is guided along the V-shaped slope by the engagement of the two,
Some are designed to orient the inserted fuel assembly in the proper direction.

However, if this is the case, complicated machining must be applied to the key and the handling head, making it difficult to manufacture! Kome 21st Strike I! '5, and the key and the V-shaped slope are in 1r11 contact, making it difficult to slip.Furthermore, the tip of the key is beveled and has an edge shape, so when I tried to arrange a new fuel assembly, When two metals come into contact with each other, the sharp end of one of them bites into the surface of the other force, damaging the surface and causing local damage (pecking, As the capacity of the reactor core increases, the inserted fuel assemblies may become unable to perform their self-positioning function. However, as it becomes larger and heavier, it is necessary to solve the problem of "galling".
It is extremely important to improve the ease of rotation of the fuel assembly during insertion.

The present invention has been made in view of the actual state of the prior art as mentioned above.
It can perform smooth rotational motion, and even if it becomes larger and its own weight increases, it will not smear by 1゛ = f, 4
An object of the present invention is to provide a fuel assembly for a nuclear reactor that has highly reliable self-orientation: J4 alignment ability and is easy to manufacture.

The present invention, which was devised to achieve the second object, has the advantage of rounding the 134th part of the handling head part and the upper end part of the intermediate polygonal cylinder part! Icoar (R) shaped guide iM in
At the same time, it is installed at the upper end of the transformer nozzle part /,: The outer surface of the tip of multiple 1- is also rounded horizontally) 2! Closing (, 1 rotation moment is applied to the fuel assembly entering offshore in two stages)
One person is directed so that the object smoothly faces the proper direction.

However, the present invention has a handling head portion located on the l end side, an intermediate polygon 1:) portion located in the middle portion having a regular polygonal cross-sectional shape, and an en portion located at the lower end portion. The handling head is cylindrical and has a cylindrical chamfer at its upper end.
The boundary between the hand link head part and the intermediate polygonal cylinder part has a continuous shape at the chamfered part of the polygonal cylinder, and the intermediate polygon 1;
At the boundary between the ) section and the transformer nozzle section, a plurality of keys of different lengths are rounded on the outer surface of the upper end and protrude toward the ridge line of the intermediate polygonal cylinder section. II: [It is a fuel collection body for a furnace.

Hereinafter, based on the drawings, the present invention will be explained in detail. ■Explain clearly. FIG. 1 (J) A small μ2 clear diagram of an embodiment of the nuclear reactor fuel assembly according to the present invention, and FIG. 2 is a view from the ■-■ arrow direction. It is a continuous rod-shaped body including a hand link head part 1 with a position 1ffi=1, an intermediate hexagonal cylinder part 2 with a regular hexagonal cross section located in the middle part, and a transformer nozzle part 3 located on the lower end side. A large number of firing pins are housed inside the hexagonal four part 2.

Now, in this embodiment, the handling head section 1 has a structure in which a cylindrical body 4 has a cylindrical ifI groove 5 formed at the upper end (top) of "E". The chamfered part of the cylinder] is not a circle It surface (, as if it were a ``bowl'').
I'm down! It is a curved surface, and when viewed in longitudinal section, it is a surface with an R such that radius R1 is equal to I. Also, the handling head *+51 and medium! 71j hexagon? I;) A chamfered part 6 of a hexagonal cylinder is formed at the boundary with part 2, and it has a continuous structure, but the chamfered part 6 of the hexagonal cylinder is also not circular, and when viewed in longitudinal section, , has radius R2 and is spherical with J: R<77-rule>.

At the boundary between the intermediate hexagonal 111 part 2 and the transformer nozzle part 3 (along the ridgeline of the intermediate hexagonal cylinder part 2)
Three keys 7a extend and protrude from the bottom J.

7b and 7c are BQ +noted. These three keys 7a, 71+, and 7c have different lengths.
a, 7b, 7cO) become smaller in order.
It is taken at intervals of N120 eaves. Each key has a spherical outer surface with a radius of 83σ (diameter R3).
, and is fitted into the groove formed on the edge of the F end of the intermediate hexagonal cylindrical portion 2.

The reactor fuel assembly constructed in this way has a self-orientation adjustment function that allows the fuel assembly itself to face the appropriate direction when replacing the new fuel assembly.
1'1-ru. The mechanism is as follows.

In order to replace a spent fuel assembly with a new fuel assembly, when one spent fuel assembly is pulled out from the core, there are six surrounding parts as shown in Figures 3 and 4. A hexagonal columnar hole surrounded by fuel assembly C is formed. For convenience of explanation], the six combustion I aggregates of Su) are denoted by the marks Q 10a and +0, respectively.
1+, toe, 10d.

10c and 10f, and the pores to be inserted are designated by the reference numeral 11. A new fuel assembly 1o is inserted into the hole 11 by 1φ from the upper part of the furnace.

As mentioned above, the refueling machine simply suspends the fuel assembly and gives it accurate direction (=J).
Therefore, the fuel assembly itself provides the orientation adjustment function.

Now, if the orientation of the new fuel assembly to be inserted matches the h position of the created hole 1'1, there will be no problem.
It is fairly rare for such a thing to occur, and it is generally the case that the fourth
As shown in the figure, some f ゛((angle 1σθ is b*'
C) When inserted and turned on, the tip of the longest key 7a first hits the cylindrical chamfer 5a of the peripheral fuel assembly 10a. As mentioned in +10, the chamfered part of the cylinder is made of RJM construction,
In addition, since the tip of the key has a structure that is rounded, it is a point contact between the spherical surfaces, and the weight of the fuel assembly 10 acts on it, so that it can be smoothly pressed without "galling". In the case of θ<30° as shown in the figure,
When viewed from one side, as shown by arrow X, it receives a rotational moment that causes it to rotate around j1, and at the same time it descends. The other keys 7b, 7G correspond to the peripheral fuel assemblies H1c, Hl(!, the cylindrical chamfered portion 5c,
The same applies when hitting 5e. In this way, the new fuel assembly 10 to be inserted is guided by the key on the cylindrical chamfered part c, the orientation is roughly adjusted, and the new fuel assembly 10 is guided downward as it is. Then, when the longest key 7a comes into contact with the chamfered part 6a of the hexagonal cylinder of the peripheral fuel assembly 10a, a rotational moment is generated in the same manner as above!・Receives [) and rotates, and each 1-1 is hit by the chamfered part of the hexagonal tube, and finally, the direction is finely adjusted and it is placed in a predetermined position. The locus of the contact point of the tip of the key 7a is indicated by the symbol P in FIG. this is,
The state in which the peripheral fuel assembly 10a is rotated 90 degrees is drawn in half of the drawing, and the locus is drawn thereon.

Therefore, in the same figure, two points Q indicate the same position -
There will be C.

In this way, by creating a two-stage structure with the chamfered part of the cylinder and the chamfered part of the hexagonal cylinder, and by making the key 11 and υ, the key receives rotational moment in two stages (), allowing coarse adjustment and fine adjustment. If it is done automatically (O is adjusted)
There is. When you want to increase the rotational moment 1- that the fuel assembly receives, you can use the two-stage structure as in this example to make the slope of the chamfered part of the cylinder steeper. 1. Say "J" to your car. Additionally, large rotational movements can be imparted through interaction with other keys.

However, although C is a fairly rare occurrence, as shown in Fig. There may be cases where the angle is approximately 30 degrees, but in such a case, if C゛ and tree 5' are clearly J, you can easily click I7.In other words, when the new fuel assembly 1o descends, the key 7a will slip. It was pushed in the direction of arrow Y, and the monument was completely covered. Then, the next key 711 activates the peripheral combustion engine '31 assembly 10c.
The new fuel assembly 10 comes into contact with the chamfered part 50 of the cylinder, and as shown by the arrow / in the same figure, a rotational upward movement occurs in the new fuel assembly 10, and the new fuel assembly 10 is inserted while rotating. Front) I: Same as in Figure 1.

In this way, the cylindrical chamfered part 5 of the handling head part 1 and the hexagonal cylindrical chamfered part 6 of the intermediate hexagonal cylinder part 2 each have an R structure, and the entrance nozzle part: = -By creating a rounded structure, [-1 galling does not occur and a large rotational moment 1
-! In addition, smooth self-orientation adjustment can be performed.

A preferred embodiment of the present invention has been described above, but
It goes without saying that the present invention is not limited to such a structure, and that significant modifications may be made within the scope set forth in Section 1.

When the middle polygon 115 part is a hexagon 1:), it is best to spell three keys [1 go is better, but 2 keys are better.

In that case, it can be placed anywhere other than the symmetrical position (180° (+7 stomach)).The chamfered part of a cylinder or the chamfered part of a polygonal cylinder should be chamfered in a circular 311 shape, but it is smooth. In order to make a rotation J3, it is best to define a "bowl" as a curved surface with such a roundness as described in the example.At this time, the center of the 7-rule must be It is also necessary for J to exist on the central axis of the burnt 1 aggregate <'K <, but it may be offset as shown in Figure 1.J: lζ, the shape of the intermediate polygonal part is also It does not fit into a hexagonal cylinder shape, and even a square cylinder shape is Jz.

The present invention (configured as described above)! , : Fuel assemblies for nuclear reactors: Fuel assemblies for nuclear reactors have become larger, the crests have increased, and smooth rotation has been achieved even if the insertion direction is incorrect. It is possible to make the robot perform a movement, and it is important to be able to quickly adjust it to the proper direction, and it is highly reliable. This is because it has an excellent IC effect.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of an embodiment of the present invention, Fig. 2 is a view from the ■ and -■ arrows, Fig. 3 is an explanatory diagram of the operation seen from the side, Fig. 4, and Fig. ! Figure j is an explanatory diagram of the operation viewed from the top ("
be. '1...Handling head part, intermediate hexagonal cylinder part for 2,
3... Engine 1 to lance nozzle part, 4 river cylindrical body, 5...
- Chamfered part of cylinder, 6... Chamfered part of hexagonal cylinder. 7a, 7b, 7cm...key, 11-...hole. Patent applicant Tokyo Electric Tsuno Co., Ltd. (and 10 others) represented
Person JE nD, tJAll Same Shigeru Tomonosuke ArakiFigure 1Figure 3

Claims (1)

[Scope of Claims] 1. A handling head portion located at the upper end side, an intermediate polygonal cylinder portion having a 11Ziα regular polygonal cross-sectional shape at the middle portion, and an entrance nozzle portion located at the lower end portion. In the continuous rod-shaped t+- reactor fuel assembly, the handling head is cylindrical and has a chamfered part of the cylinder at its upper end, and the boundary between the handling head and the intermediate polygonal cylinder is yIi is a shape that continues at the chamfered part of the polygonal cylinder, and at the boundary between the intermediate polygonal cylinder part and the 1-lance nozzle part, there are A twisted 1'11 assembly for a nuclear reactor characterized by having a round shape on the outer surface of the protruding lower end. 1.: A plurality of keys of different quality are arranged. 2. A cylindrical 161 slot, a polygonal cylinder. chamfered part, and 4
The fuel assembly for a nuclear reactor according to claim 1, wherein the outer surfaces 1.1 of the tips of the knees each have a spherical roundness. 3. A claim in which the intermediate polygonal cylinder has a regular hexagonal cross-sectional shape, the number of keys is three, and the keys are arranged at every other ridgeline of the intermediate polygonal cylinder. 1st Mi'J or the twisted II assembly for nuclear reactor according to item 2.