JPS59231478A - Coupling mechanism of control 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 [Field of Application of the Invention] The present invention relates to compaction of control rods and control rod drive mechanisms.

[Background of the invention]

Generally, a nuclear reactor is provided with control rods for controlling nuclear reactions in the reactor core in which nuclear fuel is located. A control rod contains neutron absorbing material to absorb neutrons, or is itself a neutron absorbing material, and controls the chain reaction of nuclear fuel depending on the degree to which this control rod is inserted into the reactor core. .

In order to fully control the reactor, it is necessary to insert or withdraw the control rods into the entire reactor core, and for this purpose, a mechanism for controlling the entire reactor is required.

This i! There are two main types of drive functions required for IJ rod drive mechanisms.

One is the function of inserting or withdrawing control rods in stages in a certain pinch. (Hereinafter, this function will be referred to as “Normal J
"IMIIh function". Control rods are used to adjust the power distribution within the reactor core, such as when the control rods are gradually withdrawn during reactor startup, when the control rods are withdrawn to maintain output during rated power operation to compensate for fuel reactivity deterioration, and when the control rods are withdrawn to maintain output during rated power operation. This function is required when withdrawing and inserting control rods for the purpose of carrying out operations, adjusting or replacing control rod insertion patterns, etc.

Another function of the control rod drive mechanism is to insert all control rods into the reactor core simultaneously and rapidly. (
Hereinafter, this function will be referred to as "Scrum function". ) This is a function required in the case of a normal nuclear reactor shutdown, or in the case of an emergency shutdown of the reactor due to some abnormality.

If an abnormality occurs in a nuclear reactor, all control rods are quickly inserted into the reactor core.
The ability to shut down the reactor safely is the most important issue from the standpoint of safety at nuclear power plants.

Extremely high reliability is required for the control rod drive mechanism that performs all operations of the control rods, which are the most important equipment, and for maintaining the scram function.

Conventionally, in the boiling water reactor C', the control rod drive mechanism is placed at the bottom of the reactor pressure vessel, passes through the lower mirror of the reactor pressure vessel, and the control rod drive mechanism and the control rods are connected to a cup. They are connected by a ring mechanism.

The coupling mechanism that connects the ii5 control rod, drive mechanism, and 111il control rod is a necessary mechanism to accurately transmit the movement of the 11i rod drive mechanism to all control rods, and the conditions of the fertilization are required. There is. In other words, the compulsory part can be removed with a simple operation, the drill rod and the drive mechanism part, once connected, have sufficient strength. Safety, etc. After considering the conditions of iL6, a bayonet system has been proposed as one of the coupling mechanisms.

An example of a conventional bayonet type coupling mechanism is shown in the first example.
When connecting the control rod drive mechanism 8 and the control rod 9 as shown in FIG.
Insert the cup 1 non-gross 1 attached to the tip of the control rod drive mechanism 8 and having a T-shaped cross section into the hole of the control rod coupling 2 attached to the lower end of the control rod 9 (see Figure 2). , coupling rod 1. With R fully inserted, rotate the cassilling rod 1 in the direction of the arrow shown in FIG. By inserting and rotating the campling rod 1, the cassilling rod 1 and '
It is easily and reliably connected to the #51J control rod cangling 2, and through this connection, the control rod drive mechanism 8 and the control rod 9
is definitely connected.

At this time, by providing a rotation prevention function for the control rod drive mechanism 8VC coupling rod 1, compression will not be released during reactor operation.

Next, to completely release the connection between the control rod drive mechanism 8 and the control rod 9, perform the reverse operation of the connection, that is, rotate the Cassilling rod 1 in the direction opposite to the arrow in FIG. 2, and then,
When the compling rod 1 is pulled out from the control rod compling, the coupling portion is disconnected.

An example of a bayonet-based cup-linder system has been described, but in this bayonet-type camp ring, the cassilling rod 1 and control rod camp ring 2 are combined with 7 levers when connected, so a normal drive function is required. During the insertion and withdrawal operations, the control rod drive mechanism is not transmitted to the control rod 9. There is no particular problem, but scram function is required, and the control rod 9 is moved to the core. In the case of fast insertion, there is no particular problem at the start of slow insertion and during rapid insertion, but at the end of insertion, which is stopped abruptly without prior deceleration in order to hide the entire insertion time, a great deal of force is applied to the cassilling rod 1. It will work. 1. At the end of the long-distance insertion, the Cassilling rod 1, which had been rising rapidly, is stopped on the control rod drive mechanism 8 side, but the control rod 9 is moved in the insertion direction shown in the first row. Because it has a large inertia,
Cassilling rod 1il-1: It will be rapidly pulled in the insertion direction shown in FIG.

Since the weight of the control rod 9 is heavy and the acceleration during rapid insertion is also large, a very large tensile force is applied to the suddenly stopped Cassilling rod 1, and the Cassilling rod at this time 1 needs to have a sufficiently rigid structure.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a control rod clamping mechanism that has sufficient strength by providing a bumper function to the clamping portion.

[Summary of the invention]

According to the present invention, the tensile force that would previously act suddenly on the cassilling rod is gradually applied using a buffering function such as a bumper spring provided in the bumper section on the control rod side. @
The characteristic is that it avoids severe tensile force and has a margin of strength.

[Embodiments of the invention].

An embodiment of the present invention will be described below with reference to FIG. Third
As shown in the figure, the control rod coupling 2, which was conventionally attached to the lower end of the control rod 9, is attached to the control rod 9 via a four-metal bumperon.

The buffer rod 9 is housed in a buffer part gauging 7 provided at the lower end of the control rod 9.The sofa rod 4 is connected to the buffer part casing 7 via a buffer spring 5 such as a disc spring. ing.

The camp ring between the control rod drive mechanism 8 and the 1trll lift 9 has the characteristics of the Hayofunotoka type.
Touch/Remove Operation - In order to make effective use of the characteristic that the coupling part is not released without any movement and the movement control of the control rod drive mechanism 8 is transmitted to the release mechanism 9 very accurately, the V-coupling rod 1 is used. The structure 1 function of the and spade rod coupling 2 is based on the conventional method not shown in FIG. 1, and the basic VC is 1''11-.

The coupling rod 1 and the control rod camp link 2 have the conventional type and box structure, so when connecting the camp link rod 1 and the control rod camp ring 2, the coupling rod 1 must be connected to the control rod camp link. The coupling rod 1 is inserted into the ring 2 and rotated in the direction of the arrow shown in FIG. The connection between the coupling rod 1 and the control rod clamping ring 2 is released by rotating the coupling rod and pulling it out from the control rod clamping ring 2.As shown above, the coupling rod 1 and the control rod clamping ring 2 are connected to each other. Attaching and removing the clamping part of the control rod always involves rotational movement, but the control rod is connected between the control rod clamping ring 2 and the control rod 9 via the buffer rod 4, sofa spring 5, and buffer part casing 7. 9 is only connected to control rod compling 2 and buffer rod 4.
As a method for completely preventing movement in the rotational direction of the buffer rod 4, one or more keys 6 are provided between the buffer rod 4 and the casing 7 in parallel with the axis of the buffer rod 4.

As shown in FIG. 3, the control rod drive mechanism 8 and control rod 9 after being compressed, the control rod drive mechanism 8 integrated by the compression ring, the coupling rod 1, and the control rod compression ring 2. ,ノ(The sofa rod 4 is connected to i11@wei9 and the buffer part casing 7 via the buffer spring 5. When the control rod 9 is required to perform the normal drive function, the control rod 9's self*L/ From c, since the control rod 9 is inserted and withdrawn in a state where the upper end of the buffer rod 4 and the upper end of the inner surface of the buffer part casing 7 are in direct contact with each other, the sofa spring 5 has no effect and the basic VC is the same as the conventional type, which does not carry this buffer section. Next, if control rod 9 requests the scram function,
When the control rod 9 is rapidly inserted and the control rod 9 is rising rapidly (in the insertion direction shown in FIG. 3), the upper end of the buffer rod 4 and the inner surface of the buffer part casing 7 are However, when the coupling rod 1 suddenly stops at the end of insertion, that is, when the buffer I-cond 4 integrated via the control rod coupling 2 suddenly stops, the buffer rod 4 and the buffer Since the control rod 9 and the casing 7 are not fixed, the control rod 9, which has a large inertial force, continues to rise.

Conventionally, this control rod 9 had a large inertial force, which caused a sudden tensile force to be applied to the coupling rod 1 that suddenly stopped, requiring a rigid structure for strength, but the method according to the present invention By providing a buffer spring 5 inside the buffer caning 7, the control rod 9 continues to rise after the buffer rod 4 suddenly stops. It does not suffer from sudden tensile forces, and has much more strength than conventional methods.

The structure shown in FIG. 3 is an embodiment of the present invention, and the entire cross-sectional shape of the compulsory rod 1 is shaped like the buffer rod 4 in FIG. 3, and the control rod coupling 2 and the buffer part are Alternatively, even if the buffer spring 5 is made of a leaf spring or the like and the entire buffer section has a bayonent function, no problem will occur as long as the buffer spring 5 has sufficient strength.

In addition, in the method shown in Fig. 3, the buffer rod 4 is usually
The upper end and the inner upper end of the buffer part casing 7 are in direct contact, through which the buffer passes when accelerated in the insertion direction. Compressive force acts on Rad 4. ,
@When accelerated, it becomes a sudden compressive force, this 1
In order to completely prevent the intense compression force, use a spring such as a disc spring in a part of the bath front 4. Even if it is added, it will not harm the functional metal of the mechanism shown in FIG.

According to this embodiment, the control (wholesale 9) occurs when a full scram is performed.@The characteristic tensile force is applied to the compling rod 1 by the moderating action of the buffer sgel ring 5 provided at the bumper part. , it is effective in making it far more flexible in terms of strength without affecting the strength of the blade 4.

〔Effect of the invention〕

According to the present invention, the compulsions between the control rod and the control rod drive mechanism are provided with a humming function, thereby preventing the occurrence of scrams. It is effective in making the overall strength of the control rod and control rod drive mechanism much more generous as it eliminates the need to apply a severe tensile force. In addition, since the conventional bayonet mechanism is exactly the same size, the control rod and control rod drive IJ
Another advantage is that there is no need to make any major changes to the J mechanism.

[Brief explanation of the drawing]

Figure 1 (1) is a sectional view of a compulsory part using a conventional bayonet mechanism; Figure 2 is a plan view taken in the direction of arrow A in Figure 1; (a) shows the connection state; (b) shows the connection state; Fig. 3 is a cross-sectional view showing one embodiment of the present invention. 1. Campling rod, 2. Weight control cassogling, 3. Rotation stopper, 4. Bayu/Fallond, 5. ...buffersgeling, 6...key, 7...
・Buffer part (b)

Claims (1)

[Claims] 1. A control rod coupling mechanism characterized by providing a bumper function in coupling between a control rod and a control rod drive mechanism.