JPS60252297A - Drive for 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] [Technical Field of the Invention 1] The present invention relates to a control rod drive device for controlling the output of a nuclear reactor, and in particular, to a control rod drive device for controlling the output of a nuclear reactor, and in particular, to prevent coolant from adhering to a magnetic drive section for an emergency drop operation of a control rod. The present invention relates to a control rod drive device that is designed to improve functionality by preventing

[Technical foreshadowing of the invention and its problems] Conventionally, control rod drive devices applied to fast breeder reactors were
Some configurations are shown in the figure. That is, control rods 4 containing a medium absorbing substance such as boron or tantalum 'cK are placed in the reactor core 3 of the reactor vessel 2 in which a coolant 1 made of a liquid metal such as -J-1-lium is accommodated as a fuel (not shown). It is arranged parallel to the rod, ie perpendicularly, and is removably held in the lower guide tube 5. A so-called handling head 6 is provided at the upper end of the control rod 3, and the upper edge of the inner circumferential portion thereof has a small-diameter stepped shape. It is supported in such a way that it can perform both operations of falling during normal control and falling during emergencies. In other words, the hanging pipe 7 has a long length that covers the support steps of several orders, and its mouth end is connected to the fourth lowering drive part 8. 4. The lowering drive part 8 is installed in the furnace part (J motor 9, etc., and the screw shaft 1 rotated by this motor 9).
The armpit ball nuts 1 to 11 are screwed onto the screw shaft 10. The ball nuts 1 to 11 are integrally connected to the upper end of the hanging pipe 7 via a support plate 12 and a dowel 13. Then, a rotation command from the control panel 15 based on the signal from the neutron detection sensor 14 placed in the reactor core is input to the -C motor 9 via the cable 16. 10. It is driven up and down via ball nuts 1-11.

At the lower end of the lower tube 7, a so-called latch finger '17 is formed, which is a tapered engaging part whose lower end gradually increases in diameter. This latch finger 17 is mounted on the inner periphery of the handling head 6 at the upper end of the control rod 4.

Note that the latch finger 17 is expandable and retractable, and self-propelling f
1 to J: τIML in the direction of diameter reduction.

There is something C'. Therefore, the latch finger 17 is not restrained from the inner periphery of the lifting platform (self-propelled 140 J), so that the control rod 4 can be suspended by 4 T, but the engagement rod 18 is not restrained from the inner periphery of the latch finger 17. The control rod is in a suspended state when it is pressed into contact with the control rod.That is, the engaging rod 18 is a tubular member with different diameters that is inserted into the suspension pipe 7 so that it can be inserted into the suspension pipe 7, and its upper end is connected to the suspension pipe. 7. The magnetic drive section 19 connects the magnet 1 fixed in the hanging tube 7 with, for example, an annular electromagnet 20 whose lower surface is an absorbing surface.
It consists of an armature 21 that receives an upward attractive force from the magnetically absorbing surface of the electromagnet 20. This armature 2
1 is connected to the upper end of the engagement rod 18. When the electromagnet 20 is energized, the engagement rod 18 is raised, and when the energization is stopped, the engagement rod 18 is lowered. In addition, hanging n 7
This is j7 - stopper 22 that determines the lowering limit of gear 21
has been established (). A large-diameter head 23 is provided at the lower end of the engagement rod 18, and when the engagement rod is pulled up, the large-diameter head 23 comes into pressure contact with the inner circumferential surface of the latch finger 17. Control rod 4 is restrained in the expanded diameter state.
41 for engagement with the handling head 6 of. During normal operation of a nuclear reactor, one magnetic drive unit is in an excited state and engaged with the control rod 4 in this way, and the engagement rod 1 is engaged with the control rod 4.
8 and the hanging pipe 7 are lowered 4 times by the 4 lowering drive unit 8 μ
This is used to adjust the level of the control rods 4 and control the reactor output.

In the event of an emergency (in the event of an emergency shutdown of the nuclear reactor), the energization to the electromagnet 20 is stopped, the armature 21 is dropped, and the engagement rod 18 is dropped. The latch finger 1A reduces its diameter due to its elastic force and releases the holding state of the handling head 6, and the control rod 5-4 falls from the hanging pipe 7 into the lower guide pipe 5. It is something that falls.

By the way, conventionally, the magnetic drive unit 19 for opening and closing the latch finger 17 is provided at the upper end of the hanging pipe 7 as shown in FIG.
9 to the latch finger 17
8 is a long one extending from the core 3 to the top of the reactor vessel 2, and in the unlikely event that the suspension pipe 7 or the engagement rod 18 is deformed due to external stress or thermal stress, or the sliding part If galling occurs, the lifting and lowering movement of the engagement rod 18 may be impaired, which may impede the separation movement of the control rod 4.

For this reason, it has recently been considered to shorten the engaging rod 18. For example, the magnetic drive section 19 is placed below the hanging tube 7, for example, at the position shown in the imaginary line area A in FIG. The height from one drive part to the latch finger 17 is made small, and the engagement rod 18 is made into a short rod shape. This not only makes it possible to reliably disconnect the control rod 4 due to thermal deformation, but also simplifies the component configuration.
: The number of sliding parts is reduced, which reduces the influence of external stress and the occurrence of galling, making it possible to achieve reliability ↑ (white clay of 1).

However, in this case, as the magnetic drive unit 19 approaches the reactor core 3, the electromagnetic force that constitutes the magnetic drive unit 19 increases. ”
i 20 and armature 21 are placed below the surface of a cold liquid, e.g. Then, the fine powder-like solid substances in the liquid 1~lium will be transferred to the electromagnet 2.
0 and armature 21 on each adsorption surface, and then
There is a risk that the gap between the suction surfaces will expand and the suction force will decrease. Furthermore, if the attached foreign matter is large, it is possible that the electromagnet 20 and the armature l-21 cannot be joined together, making it impossible to connect the control rod 4 to the n1 lower pipe 7 later. In particular, the liquid sulfur, which is frequently used as the coolant 1, is highly likely to contain metal powder generated by sliding friction of various devices, and it is considered that the above phenomenon is likely to occur.

Note that even when the electromagnet 20 and the armature 21 are disposed near and above the liquid level, the same problem as described above may occur due to metal vapor deposition on the suction surface due to the vapor atmosphere.

[Object of the Invention] The present invention has been made in view of the above circumstances, and it is possible to prevent solid substances such as fine powder in the cold lJ1 from entering or adhering between the electromagnet and the armature. It does not interfere with the operations such as disconnecting and connecting, and can be used in emergencies [Reliable operation +! The goal in January is to provide a control rod drive system that can improve the quality of the control rod.

[Summary of the Invention] In the control rod drive device according to the present invention, the control rods are connected to the reactor core via the tail tube to the descending drive section provided at the bottom of the reactor vessel. At the same time, an engaging rod for cutting the control rod from the hanging pipe is inserted into the hanging pipe so that it can be lowered by 4 degrees relative to the hanging pipe, and The magnetic drive unit has a magnet fixed in the hanging pipe and an armage A7 connected to the magnet and an engaging rod that moves toward and away from the magnet. In the installed control rod drive device, a cooling moon shielding member is installed in the suspension pipe to prevent cooling H from entering the magnetic drive unit.
It has a three-dimensional structure.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

41. Components common to the conventional control rod drive device will be described using the same reference numerals as in FIG. 4.

A large diameter tubular drive unit housing 3 is located at the upper part of the reactor vessel 2.
1 is fixed vertically, and the lower end of this drive unit housing 31 is connected to an upper guide tube 33 fixed to a rotating plug 32 for closing the reactor vessel.

A tail tube 7 for raising and lowering the control rod is disposed within the drive housing 30 and the two-part guide tube 33. The hanging pipe 7 is connected to the motor 9 attached to the drive unit housing 30-L.
The screwdriver shaft 10, a pole nut 11, a support plate 12, and a load cell 13 are connected to each other. The load cell 13 measures the =9-hip-down distance of the hanging tube 7 to ensure the downward movement.
-Udapano).

The lifting pipe 7 has a diameter of +7.7 (11 lateral mass 7ε)
, connecting the middle pipe part 7b and the lower pipe part 7G lN7ri,
7e (111 completed. 1 part guide 1" 332 and upper pipe part 7a 1 and 1 rotation in which gap)'
One part of the biological shield 33 is fixed to the inside of the guide ↑ 132 at the same height as the jig 31 (J, this biological shield 33
A base 34 is provided between the lower end of the upper tube portion 7a and the connecting plate 7 ('j, the peripheral portion of the upper tube portion 7a is connected to the lower end 7) 11.
It is airtightly closed. Note that a different bellows 35 is also mounted from one end of the upper pipe portion 7a, and this
A shielding plate 36 is provided at the lower end of the L-side tube portion 7a (the inside of the L-side tube portion 7a is also airtightly closed from below).
Reed switch 37 is installed on the inner periphery of the 1 end of a, i-J, 1
1. By detecting the height positions of the magnets 1 to 39 at the upper end of the rod 38 protruding below the armature 21 that covers it,
The separation or connection operation of the control rods 4 can be confirmed.

The middle tube section 7b of the hanging tube 7 is formed to have a large diameter, and the lower tube section 7G is formed to have a small diameter. The upper end of an acceleration spring 40, which is a compression coil spring arranged around the lower tube section 7C, is in contact with the connecting plate 7e at the lower end of the middle tube section 7b. The lower end of this acceleration spring 40 is in contact with the upper end of an acceleration tube 41 disposed on the outer periphery of the lower tube portion 7G, and the lower end of this acceleration tube 41 is in contact with the upper end of the control rod 4, so that the control rod 4 is accelerated by the spring force of the acceleration spring 40. In addition,
” A stopper 42 partially protruding from the lower end of the inner circumference of the indoor pipe 33
A damping spring 43 is supported on the top, and this damping spring 43 provides a more constant support angle to the acceleration tube 41.

A latch finger 17 is provided at the lower end of the hanging pipe 7 as an expandable and contractible tapered latching portion that is given an elastic force in the diametrical direction, and this latch finger 17 serves as an annular latching portion at the upper end of the control rod 4. 1-. A large-diameter head 23 provided at the lower end of the engagement rod 18 inserted into the suspension tube 7 is in sliding contact with the inner peripheral portion of the latch finger 17 .

11- The engagement rod 18 has a short rod shape, and this engagement [1 rod 18
The magnetic drive unit 19 that raises and lowers the lower pipe part 7C of the hanging pipe 7
It is located in That is, a large diameter pipe part 7f is formed in the lower pipe part 7C of the hanging pipe 7, and an electromagnet 20 is fixed to the inner upper part of this large diameter pipe part 7G, and an armature 21 is mounted opposite to the lower surface of this electromagnet 20. An engagement rod 1B is connected to the lower surface of the armature 21. In addition, a rod 38 is provided on the upper surface of the armature 21 so as to protrude from the upper surface of the engagement rod 18, and is arranged on the axis of the 10,000 extension of the engagement rod 18.
39 is connected to the magnet 1 to confirm the disconnection or connection operation of the control rod 4. Further, a flange-shaped spacing 22 is provided at the inner lower portion of the large diameter tube portion 7f to determine the lowering limit of the armage 1721.

During normal operation, the electromagnetic force C20 of the magnetic drive section 19 is excited, the armature 21 is attracted in the - direction, and the engagement rod 18 is held in the - raised position. As a result, the large-diameter head 23 at the lower end of the engagement rod 18 remains at the position where the diameter of the latch finger 17 is reduced by M1, and the latch fin 17 holds the handling head 6 of the control rod 5 in the one-turn state. maintained. By driving the motor 9 in this state, the level of the control rod 5 is adjusted and the output of the reactor is controlled.

In an emergency, the electromagnet 20 is de-energized and the engagement rod 1
8 descends. As a result, the large diameter head 23 extends IB2 downward from the latch finger 17, and the latch fin 17
is allowed to be reduced in diameter. Thereupon, the latch finger 17 elastically contracts in diameter to release m1 of the handling head 6, so that the control rod 5 rapidly falls due to the downward force of the lever and the acceleration spring 40.

By the way, the magnetic drive unit 19 for performing the above operation is located in the lower pipe part of the hanging pipe 7, that is, the liquid liquid 1 to
It is disposed below the liquid level 1a of the lium 1. Therefore, there is a possibility that the liquids 1 to 1 may enter the opposing portions of the electromagnet 20 and the armature 21 in the hanging tube 7 through the lower end of the upper guide tube 33 and the like.

Therefore, in this embodiment, the inside of the hanging pipe 7 is cold = 13
- A pair of bellows 45, 46 are provided at the upper and lower portions of the magnetic cooling unit 19 as material shielding members.

Eleven bellows 45 on the upper part of the magnetic cooling unit 19 are disposed between the inner circumference of the suspension tube 7 corresponding to the electromagnet housing position and the outer circumference of the armature 21.
The mutual suction surfaces of 0 and 21 are shielded from below to prevent liquid helium 1 from entering between the suction surfaces. Furthermore, the base 46 of the magnetic cooling J1 section 19-1 is disposed in a space 47 provided at a slightly nil position of the large diameter tube section 7f of the hanging tube 7. This bellows 46 is connected to the inner wall of the space 47 and the rod 38.
This shields the mutual attraction surface between the electromagnet 20 and the armature 21 from below.

If the bellows 45, 46 have the coolant shielding function in this way, each bellows 45, 46 will expand and contract even if the hanging pipe 7 and the engaging rod 18 are moved relative to each other in the 11 directions. This allows the coolant shielding function to be maintained. That is, as shown in FIG. 2, during normal operation, the armature 21 is attracted by the electromagnet 2014-, so that the engaging rod 18 and the rod 3
8 is extended within the suspension pipe 7, and each bellows 45° and 46 are in a contracted state. In addition, as shown in Figure 3, J11
When the power to the electromagnet 20 is cut off, the armage 1121
is scraped downward from the electromagnet 20. When the engaging rod 18 and the rod 38 are lowered within the hanging pipe 7, the bellows 45 and 46 are in an extended state. In this way, in any state of the engagement rod 18, the bellows 45, 46 close the magnetic drive unit 19 from the outside, thereby preventing coolant from entering.

In the above embodiment, the bellows 7 at the bottom of the magnetic drive unit 19
One end of I5 is attached to the outer periphery of the armature 21, but this is attached to the largest diameter part on the engaging rod 18 side.
The sealing effect is improved by removing the swivel 45, and is not necessarily limited to this.
-GH+ of the lens 45 may be attached to the outer circumference of the engagement rod 18.

Further, the electromagnet 20 is close to the third portion of the reactor core.

Therefore, this electromagnet 20 will be installed at a location where the temperature of the liquid sodium 1 flowing inside the reactor core 3 can be easily detected. Therefore, as shown in FIG. 2 and FIG.
If it is equipped with this, it will be possible to detect the temperature and automatically shut down the furnace, eliminating the need to rely on the conventional sensors and human operations, making it an extremely excellent safety measure.

[Effects of the Invention] As detailed above, the present invention provides a drive unit for an engagement rod, that is, a magnet 1 for performing an emergency disconnection operation of a control rod.
~d5 and the magnetic drive unit in the armature are placed near or below the coolant liquid level, and the coolant is prevented from entering the magnetic drive unit in the downstream pipe for lowering the control rods 4. Since a coolant shielding member is installed to prevent the fine powder and other solid substances contained in the coolant from entering between the suction parts of the magnet and armage, etc. It is possible to eliminate the risk of damage caused by intruding objects during operations such as separation and connection of control rods.

In particular, the reliability of IJ operation during emergencies can be improved, increasing safety.
6 - All measures will have a great effect.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the control rod drive device according to the present invention, and FIG. 1 shows the entire device, with a J sectional view;
Figures 2 and 3 are action explanatory diagrams showing the main parts enlarged;
FIG. 4 is an overall sectional view showing a conventional example. 1...Liquid helium (cold 7JI material), 2...Reactor vessel, 3...Reactor core, 4...Control rod, 6...Handling head (annular locking part), 7...・Suspended quality, 8
... Lifting drive unit, 17... Latch finger (tapered latching part), 18... Engagement rod, 19... Magnetic drive unit, 2o... Electromagnet (magnet 1~), 21...・・・
Armature, 23...Large diameter head, 45.46...Bellows (cold 1i 1 month cutoff part month). Attorney 10 Kensuke Norichika (and 1 other person) -17-

Claims (1)

[Claims] 1. Y? installed in the tenth part of the reactor vessel? The control rod is suspended in the lowering drive part via a suspension pipe so that it can be raised and lowered from the reactor core, and an engaging rod is provided in the suspension pipe for detaching and dropping the control rod from the suspension pipe as a magnetic drive part. (j) The magnetic drive unit is inserted into the hanging pipe so as to be able to rise and fall relative to the hanging pipe, and the magnetic drive unit has an armature fixed in the hanging pipe and connected to lζ magnets 1 to 1 to which an engaging rod is connected. , in a control rod drive device in which the magnets 1 to 1 and the armature are arranged near or below the liquid level of the cooling H, a cooling device that prevents coolant from entering the magnetic drive part in the hanging pipe. A control rod drive device characterized by being provided with a material shielding member. 2. The shielding member is located between the inner periphery of the hanging tube near the magnet housing and the outer periphery of the armature or the outer periphery of the engagement rod.
■ nM (J
&Special M which is a pair of bellows arranged above and below the air drive part
'F A control rod drive device according to claim 1. 4. The control rod drive device according to claim 1, wherein the magnet 1 is an electromagnet having a built-in detection part that blocks the supply of electricity depending on the temperature of the coolant.