JP2702993B2 - Heat resistant drive coil and control rod drive - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control rod driving device for a nuclear reactor and a driving coil used in the control rod driving device.

<Related Art> Various types of control rod driving devices for a nuclear reactor are used as a driving source. In the case of an electromagnetic driving type, a control rod is driven by an exciting force of a driving coil and is inserted into and removed from a reactor core. Sixth
FIG. 1 is a cutaway perspective view of a typical control rod driving device, and FIG. 7 is a sectional view of a conventional driving coil. In the control rod driving device 1, as shown in FIG. 6, a drive shaft 10 to which a control rod is connected is provided at the center at a lower portion thereof, and three drive coils are provided around the drive shaft 10. 11,12,13 are located side by side. The drive shaft 10 is housed in a drive shaft housing 14, and the drive coils 11, 12, and 13 are housed in a coil housing 15, respectively.

The lower stationary gripper coil (hereinafter, referred to as SGC) 11 as a drive coil operates a fixed gripping latch 17 housed in a latch housing 16 and is used when the reactor is operated at a constant output. The SGC 11 is continuously excited to hold the drive shaft 10 (control rod) at a fixed position. An intermediate movable gripper coil (hereinafter referred to as MGC) 12 is a latch housing 1
This actuates the movable gripping latch 18 housed in 6 and is excited when the drive shaft 10 moves up and down. An upper lift coil (hereinafter, referred to as LC) 13 raises or lowers the drive shaft 10 and is excited at that time.

The reason that the SGC11 is always excited during the operation of the reactor is that the control rod naturally falls into the reactor core due to the non-excitation state of the SGC11 in the event of a power failure during operation, and the reactor is operated. This is based on the so-called fail-safe design concept of maintaining the safety of the reactor by tripping.

As shown in FIG. 7, a cylindrical bobbin 20, which is a molded product of glass silicon resin, is attached to the drive shaft housing 14, and a copper conductor is wound around the bobbin 20 by a double glass winding. A wire 21 covered with a covering material (H class insulator) is wound. Lead wires 22 are connected to both ends of the wire 21. Further, in order to hold the wire 21, the gap is filled with a filler 23 mainly composed of silicone resin, and the outer periphery thereof is covered with the outer cylinder 2.

The heat resistance temperature of this conventional drive coil was limited to about 200 ° C. due to the properties of the constituent materials. If the temperature becomes higher than this, oxidation proceeds, and for example, there is a fear that the coating material of the copper conductor is peeled off.

By the way, each drive coil 11,12,
The temperature of the coil 13 rises due to its own resistance heat generation. For example, the currents flowing through MGC12 and LC13 each
And 40 A, but the current flowing through the SGC 11 is 8 A instantaneously and 4.4 A continuously. The current of MGC12 and LC13 is large but instantaneous, while the current of SGC11 is relatively small but flows continuously during operation of the reactor.
The temperature of 1 becomes higher than other drive coils and rises to around 200 ° C. This is because the resistance value of the copper conductor of the wire 21 increases with time due to the high ambient temperature. Further, the periphery of the coil housing 15 is further heated by heat conduction from the core, and the temperature of the coil becomes 4 while the SGC 11 is excited.
There is a possibility that the temperature may rise to about 50 ° C., and as a result, the coil may be damaged or deteriorated.

Therefore, the conventional control rod driving device 1 forcibly circulates the air around the coils in order to prevent the temperature of each of the driving coils 11, 12, and 13 from rising due to self-heating or external factors. It has a cooling device for cooling.

FIG. 8 is a configuration diagram of a conventional cooling device for a control rod driving device,
FIG. 9 is a partially cutaway side view of a reactor equipped with the cooling device. As shown in FIGS. 8 and 9, each control rod driving device 1 disposed on the upper lid 3 of the reactor vessel 2 is cooled by cooling air supplied from the outside. That is, the cooling air for cooling the control rod driving device 1 enters the cooling chamber 30 in which a large number of the control rod driving devices 1 are accommodated, cools the cooling room 30, and then becomes hot air to form the ring duct 31.
It is further discharged to the outside and sent to the cooling unit 33 through the pipe 32. The hot air sent to the cooling unit 33 is cooled here to become cooling air, and is sent again to the cooling chamber 30 by the cooling fan 34 to cool the control rod driving device 1.

<Problems to be Solved by the Invention> As described above, the conventional drive coil has not so good heat resistance, and therefore, the control rod driving device 1 is conventionally provided in the nuclear reactor.
It was necessary to install an air conditioner for cooling the air conditioner. Along with this, additional equipment such as fans, ducts, and piping for supplying cooling air and discharging hot air was required, and the reactor became large-scale. Furthermore, the surrounding structure has become complicated, and the cost spent on it has become enormous. Further, there has been a problem that the inspection and repair work of the nuclear reactor and the removal of the cooling pipe at the time of refueling and the installation work are troublesome, and the time and personnel required for the work are also large.

The present invention solves such a problem, and is not damaged or deteriorated by self-heating of the coil or external heating, and does not require a special cooling device. It is intended to provide a device.

<Means for Solving the Problems> A heat-resistant drive coil according to the present invention for achieving the above-mentioned object comprises a ceramic or metal cylindrical bobbin, and a conductor coated with ceramic on the outer peripheral portion of the bobbin. It is characterized by comprising a wire wound around the coil to form a coil, and a ceramic filler filled in a gap between the wires.

Further, a control rod driving device according to the present invention for achieving the above object is characterized in that the heat-resistant driving coil is used as a driving coil of a control rod.

<Operation> Since the components of the heat-resistant drive coil are made of a ceramic material, the heat resistance is improved.

Further, since the control rod driving device using the heat-resistant driving coil can be operated at a high temperature, there is no need to provide a cooling device and ancillary equipment thereof, and the reactor and its surrounding structures are simplified.

<Embodiment> Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

1 is a longitudinal sectional view of a heat-resistant driving coil according to an embodiment of the present invention, FIG. 2 is a side view thereof, FIG. 3 is a plan view thereof, and FIG. 4 is a sectional view of a wire used for the heat-resistant driving coil. , Fifth
FIG. 1 is a partially cutaway side view of a nuclear reactor showing a control rod driving device equipped with a heat-resistant driving coil of the present embodiment. Note that the same members as those in the related art are denoted by the same reference numerals, and redundant description will be omitted.

First, the heat-resistant drive coil will be described. As shown in FIGS. 1 to 3, a cylindrical bobbin 51 having a flange portion 50 protruding outward around the entire upper and lower portions is made of stainless steel (SUS304), and the outer peripheral surface thereof is formed. A ceramic sheet as a ceramic covering material is adhered as necessary. Note that the bobbin 51 may be made of machinable ceramic. A ceramic electric wire 52 as a wire is wound around the bobbin 51 by a predetermined number of turns to form a coil. As shown in FIG. 4, the ceramic electric wire 52 is formed by coating a nickel-plated copper conductor 53 with a ceramic coating material 54, providing an insulator 55 on the outer periphery thereof, and further forming a ceramic coating material 56 on the outside thereof.
The conductor 53 has a slightly larger wire diameter than a conventional wire. Here, in consideration of the manufacturability of the ceramic electric wire 52 as a coil, it is preferable that a wire coated with a ceramic coating material is formed into a coil, sintered, and then turned into ceramic and heat resistant. In addition, as the ceramic coating materials 54 and 56, aluminum oxide (alumina-based), silicon oxide (silica-based), or the like, or a mixture thereof can be used. And bobbin
Lead wires 57 for electric conduction composed of an MI cable are connected to both ends of the ceramic electric wire 52 wound around 51 by spot welding.

In the gap between the ceramic wires 52 that are wound around and overlapped with the outer periphery of the bobbin 51, a ceramic-based filler (for example, ceramer bond) 58 is used in a necessary amount to prevent the ceramic wires 52 from being loosened and caused by vibration. It is filled by impregnation by pulling. Further, a reinforcing outer cylinder 59 made of the same material as that of the bobbin 51 is attached to the bobbin 51 so as to cover the entire wound ceramic electric wire 52 and to be located around the outer periphery thereof. Instead of the outer cylinder 59, a ceramic sheet may be attached to the outer peripheral portions of the ceramic electric wire 52 and the filler 58, or a ceramic material may be applied.

In the heat-resistant drive coil configured as described above, the heat-resistant temperature of the above-described bobbin 51 is 600 to 800 ° C., and the wire 52 is made of nickel-plated copper that excels in deterioration characteristics at the time of temperature change for the conductor 53, and Because of ceramic coating, its heat-resistant temperature can be 450-800 ° C. Further, since the diameter of the conductor 53 is made large, its electric resistance value is low, and it is possible to cope with an increase in resistance at high temperatures. In addition, ceramic filler 58
Has a heat resistance temperature of 1400 ° C., a heat resistance temperature of the lead wire 57 composed of the MI cable is 600 ° C., and a ceramic sheet or ceramic coating material is 500 to 800 ° C. Therefore, the heat-resistant drive coil composed of these components can raise the heat-resistant temperature by several steps as compared with the conventional one, and can be increased by about 450
Even if heated at ℃, it can withstand sufficiently without deterioration.

Further, since the ceramic filler 58 has a strong adhesive force and an appropriate viscosity, its thermal conductivity is improved, and transmission of mechanical vibration can be prevented. The ceramic sheet attached to the surface of the bobbin 51 and the outer cylinder 59 absorbs a difference in thermal expansion between the filler 58 and the ceramic sheet, so that the stability over time and durability can be improved.

The heat-resistant drive coil of this embodiment has characteristics other than the above-described heat-resistant characteristics, namely, radiation-resistant characteristics, electric characteristics (withstand voltage characteristics, insulation resistance characteristics, conductor resistance characteristics) and mechanical characteristics (thermal conductivity, expansion). (E.g., modulus, flexural strength) as compared with conventional ones, or more. Further, even when comparing the sizes, the dimensions of the bobbin, the diameter of the wire, the number of windings, the conductor resistance, the dimensions of the magnetic circuit around the coil, the material, and the like are the same, and the heat-resistant driving coil of the present embodiment is the same. Can generate a magnetomotive force and a magnetic flux (magnetic force) equivalent to those of the related art.

As described above, the heat-resistant drive coil of the present embodiment can withstand even when heated at a high temperature and thus can be operated at a high temperature.Therefore, by using this heat-resistant drive coil for a control rod drive of a nuclear reactor, The coil cooling equipment can be eliminated.

That is, as shown in FIG. 5, in a nuclear reactor equipped with a control rod driving device using the heat-resistant driving coil, a cooling air-conditioning system for the control rod driving device conventionally provided at the upper part of the reactor is used. Not equipped. Therefore, equipment such as a supply / discharge duct, a pipe, a cooling unit, and a cooling fan as a cooling device is not required, and the reactor and its surrounding structures can be simplified. Further, enormous costs for designing the cooling device, purchasing materials, and construction can be reduced.

<Effects of the Invention> As described above in detail with the examples, according to the heat-resistant drive coil of the present invention, each member constituting the heat-resistant drive coil is made of a ceramic-based material. The heat-resistant temperature can be increased without losing the characteristics of the drive coil.

Further, since the control rod drive device of the present invention uses the heat-resistant drive coil as the drive coil of the drive shaft, the cooling device and its auxiliary equipment which were conventionally required can be dispensed with, and the reactor and its surroundings can be eliminated. The structure can be simplified. This makes it possible to reduce the cost of designing, constructing, and using materials for the cooling device, and to facilitate the inspection and repair work of the reactor.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a heat-resistant drive coil according to an embodiment of the present invention, FIG. 2 is a side view thereof, FIG.
FIG. 5 is a cross-sectional view of a wire rod used for a heat-resistant drive coil, and FIG. 5 is a partially cutaway side view of a nuclear reactor showing a control rod drive device equipped with the heat-resistant drive coil of the present embodiment. FIG. 6 is a cutaway perspective view of a general control rod driving device, FIG. 7 is a sectional view of a conventional driving coil, FIG. 8 is a configuration diagram of a conventional cooling device for a control rod driving device, and FIG. FIG. 2 is a partially cutaway side view of a nuclear reactor equipped with the cooling device. In the drawing, 1 is a control rod drive, 10 is a drive shaft, 51 is a bobbin, 52 is a ceramic electric wire (wire), 53 is a conductor, 54 and 56 are ceramic coating materials, 57 is a lead wire, 58 is a ceramic filler, 59 is an outer cylinder.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shinichi Murakawa 2-1-1, Shinhama, Arai-machi, Takasago-shi, Hyogo Prefecture Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Tatsuhiko Hiramoto Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo Prefecture 1-1, 1-1 Mitsubishi Heavy Industries, Ltd. Kobe Shipyard (56) References JP-A-2-36396 (JP, A)

Claims (2)

(57) [Claims] 1. A bobbin having a cylindrical shape made of ceramic or metal, a conductor coated with ceramic on the surface of a conductor and wound around the outer periphery of the bobbin to form a coil, and a ceramic material filled in a gap between the wires. A heat-resistant drive coil comprising a filler. 2. A control rod driving device for a nuclear reactor, wherein the heat-resistant driving coil according to claim 1 is used as a driving coil for driving the control rod.