JPS5926091A - Wire spacer type nuclear fuel rod - 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 has a structure in which a Jneu A7 spacer is wound around the outer periphery of the fuel bottle 1'3F, and the I!8 is held between the fuel oil 11 bins by the wire. For more information about the voice nuclear fuel rod.

This is a device that is attached to a nuclear fuel rod that is capable of suppressing as much as possible the wear of the covering fuel cladding caused by fluid vibrations.

The conventional Y A7 spacer type nuclear fuel 1'81 rod (well, the same material as the 1 cover and the Y A7 spacer (Torihata 5US31G), the same degree of cold working (A material) was used. There is such a thing.
During operation, a nuclear fuel rod contacts and collides with an adjacent nuclear fuel rod due to cold body vibrations, and the fuel cladding tube and the spacer wire of the adjacent nuclear fuel rod (causing mechanical interaction). The coating material is worn out.The occurrence of such wear means a local decrease in the thickness of the coating color, and the conditions for planning the integrity of the fuel pin are strict.

In order to prevent wear, there is a method of reducing the vibration by narrowing the spacing between the nuclear fuel rods. However, this method naturally narrows the gap between the fuel pins, so
This makes it difficult to store the pin bundle inside the trumpet tube. In addition, we reduced the manufacturing tolerances of the outer diameter of the fuel pin cladding tube, the outer diameter of the wire, and the distance between the inner surfaces of the wrapper tube, and reduced the gap density of the fuel pin bundle (movement per bottle19). It is necessary to make sure that the value of the above-mentioned void density does not become too large, and also that the value of the above-mentioned void density does not become negative (so that the value of the cladding, wire, and trumpet tube There is also the drawback of entering the 311 into the 1st gear. Historically, because the spacing between the 4 pins is small, interaction between the end of the bottle and the 411 (which 411) is likely to occur due to the swivel ring, and the 411 '414 When life gets shorter, there are 91 drawbacks.

The purpose of the present invention is to -1 J, Umoto-(1η next technique ((・
The objective is to provide a highly safe 7-sphere nuclear fuel rod that eliminates the shortcomings of I, does not reduce the fuel pin spacing, is easy to manufacture and assemble, does not cause cladding wear, and is highly safe. .

In the present invention, which can achieve such an object, the material of the spacer wire and the fuel cladding tube is made of sulinless steel of the same composition,
Spacerai A7 is t3! i l'l Wire spacer type nuclear fuel gamma l using a material with a degree of cold working smaller than that of frost-covered dust
It's a stick.

The present invention will be explained in more detail below.

The drawing is an explanatory diagram showing an example of a YA7 Spacey type nuclear fuel rod. The nuclear fuel bottle is the same as the conventional one, 1 burner 1 cladding tube 1
It is a groove light in which nuclear fuel pellets (~2% Ig L) are laminated inside, and both ends are sealed with an upper end plug 3 and a lower end plug 4.

Note that the code 5 is a =1 irsprinter for holding down the LJ nuclear fuel type berets 1 and 2. A wire base is wound around the outer periphery of the 1st pin of the fuel, and the wire 1?
'8+ pin spacing is maintained. In the present invention, the spacer layer 176 and the spacer layer 176 are made of stainless steel with the same composition, but the spacer layer 81 coated basket 1 and the spacer layer 176 are made of stainless steel with the same composition, but the spacer layer 81 coated basket 1 and the spacer layer 176 are made of stainless steel with the same composition. It is highly processed.

Here, the degree of cold work means +A H'! before processing. length 1
0, when the tA material length after processing is set to Ll, 100x
m is defined as (Ll - LO)/LO (%).

In the present invention, fuel cladding color 1 is 1, cold 1+t
S tJ S 31G stainless steel with 1T degree of 20%,
The wire spacer 6 is made of IJ, 5US31G stainless steel with a lower degree of cold work, such as 15% or 10%, or annealed (with a degree of cold work of 0%).
SUS31G Suanless steel can be used. S
For example, the annealing heat treatment of US 31G is about several minutes at 1000 to 1100''C.

In the nuclear fuel rod according to the present invention, when the optical suspension of fast neutrons is low, due to the difference in the degree of cold working, the fuel cladding tube
The surface hardness of the spacer 6 becomes higher than that of the spacer 6, and due to the vibration of the 148 body, no wear phenomenon occurs even if the adjacent bottle glue 18 moves in contact with the spacer. . Furthermore, when the shank 31 is irradiated with high-speed neutrons, its hardness increases and converges to a constant value regardless of the cold processing during manufacturing.

For this reason, if the fuel ('31 cladding tube 1 and the wire material G are made of the same material), the same hardness will occur.
The wear phenomenon due to contact sliding is high)
Due to the increase in the number of villages, the number of villages will increase.

However, the degree of cold working of the wire spacer 6 is
In the nuclear fuel 1131 rod of the present invention, which has a cold working degree smaller than that of Since the smaller wye ψ space is larger, a current dispute arises where the wye is 7 or less. For this reason, the kinetic energy of the lie 1a that hits the cladding becomes smaller, and the contact position changes as the reactor starts and stops, and the fuel Plrrl
The loss of pipe wall thickness will not reverse. However, there is no significant thinning that would lead to damage to the fuel bottle.

As mentioned above, the spacer line 7 has a smaller degree of cold working than the fuel cladding tube, and in the initial stage the fuel cladding tube has a surface hardness greater than that of the fuel cladding tube. Wear caused by contact sliding between fuel bottles due to fluid vibration does not occur in the fuel tube, and it is also susceptible to high-speed neutrons! ,! 4 desk te'noi A7 space 11
If the hardness of the cladding increases (the hardness of the cladding tube) and approaches the condition where a wear phenomenon occurs, the wire becomes loose due to the swelling and creep that occurs in the spacer, and the wear phenomenon may not occur or may occur. However, it stops at an early stage.

Accordingly, according to the present invention, when constructing a nuclear fuel i'1 solution, the space between the nuclear fuel rods 1; 14 is easy to manufacture and erect, and wide spacing is sufficient, safety is high, and manufacturing is easy. I would like to propose a 1':1 ratio to prevent the strike from becoming too high.
E2, there is a very unusual effect.

[Brief explanation of the drawing]

The drawing is an explanatory diagram of an example of a Y\7 spacer type nuclear fuel rod. 1... Nuclear fuel '31 coating material, 2... Nuclear fuel P17-J
1-13... Soil end plug, 4... Lower end frame, 5...
・=1 Il Sujiring, 6...Y A7 space →]
. Patent applicant Representative of Power Reactor/Nuclear Fuel Training Development Small Business Group
Human tail crotch line 1) 1 same
Shindo Shigeji
Aramoto Tomonosuke499-

Claims (1)

[Claims] 1. Wire 17 is installed in a nuclear fuel rod J3 having a structure in which it is wound around the outer periphery of a fuel pin using a spacer. However, a nuclear fuel rod of the life type nuclear fuel rod is characterized in that the fuel rod is of a cold working degree smaller than the combustion tube. 2. The nuclear fuel rod according to claim 1, wherein the stainless steel is 5Us316 stainless steel. 3. The nuclear fuel rod according to claim 2, wherein the degree of cold working of the fuel cladding tube is about 20%, and the degree of cold working of the spacer wire 7 is about 15%.