JPH0353593B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nuclear reactor control rod control device, and in particular, to a nuclear reactor control rod control device for inserting or withdrawing a control rod used for controlling the thermal output of a nuclear reactor and shutting down the reactor. This invention relates to a control device for a control rod drive mechanism used.

FIG. 1 shows a simplified structure of a magnetic jack type drive mechanism for nuclear reactor control. In the figure, a lift coil 1 and a movable gripper coil (hereinafter referred to as MG) installed outside the reactor pressure vessel are shown.
Three coils, a stationary gripper coil (hereinafter referred to as a SG coil) 2 and a stationary gripper coil (hereinafter referred to as an SG coil) 3, operate an excitation armature housed in the reactor pressure vessel. That is, the movable gripper armature 4 and the stationary gripper armature are connected to the MG coil 2 and the SG coil 3, respectively.
When energized, actuates latches 7 and 8 which engage troughs or grooves 6a in control rod drive shaft 6.
Stationary latch 8 is used to hold control rod drive shaft 6 in a certain position. The movable latch 7 is raised and lowered by the lift armature 9 when the lift coil 1 is excited, and is used to raise and lower the control rod drive shaft 6 (move in the withdrawal direction) and lower (move in the insertion direction). movement). In addition, 1a is a lift magnetic pole, 3a is a stationary gripper magnetic pole, 5 is a stationary gripper armature, 7a is a movable latch link, and 8a is a stationary latch link.

FIG. 2 shows the operation sequence of the control rod drive mechanism. In FIG. 2, corresponding parts in FIG. 1 are represented by the same reference numerals, but the movable latch 7 and the stationary latch 8 are shown in a simplified manner.

The control rod withdrawal sequence and insertion sequence will be described below with reference to FIGS. 1 and 2.

A: Removal sequence (a) In the standby state, the SG coil 3 is energized, the stationary latch 8 is closed, and holds the control rod drive shaft. [Status shown in Figure 2 a-b] (b) Excite the MG coil 2 and close the movable latch 7.
Close. [Conditions shown in Figure 2 a-b] (c) Demagnetize the SG coil 3 and release the stationary latch 8. [States in Figure 2 a-c] (d) The lift coil 1 is energized to operate the lift armature 9 and the movable gripper armature 4 is raised. As a result, the control rod drive shaft 6 supported by the movable clutch 7 is raised in the direction of the arrow by one groove 6a of the control rod drive shaft. [States shown in Figure 2 a-d] (e) Energize the SG coil 3 and close the stationary latch 8. [Status shown in Figure 2 a-e] (f) Demagnetize the MG coil 2 and close the movable latch 7.
to release. [Status shown in Figure 2 a-f] (g) Demagnetize the lift coil 1 and lower the lift armature 9 in the direction of the arrow. [Status shown in Figure 2 a-t] (H) Repeat operations from B to G.

B: Insertion sequence (a) In the standby state, the SG coil 3 is energized, the stationary latch 8 is closed, and the control rod drive shaft 6 is held. [Condition shown in Fig. 2 b-a] (b) Excite the lift coil 1 to raise the lift armature 9 in the direction of the arrow. [Figure 2 b-
Condition B] (C) Excite the MG coil 2 and close the movable latch 7. [State of Fig. 2b-c] (d) Demagnetize the SG coil 3 and release the stationary latch 8. [Status shown in Figure 2 b-d] (e) Demagnetize the lift coil 1, lower the lift armature 9, and lower the movable gripper armature 4. The control rod drive shaft 6 is now lowered in the direction of the arrow by one groove 6a.
[Condition shown in Fig. 2 b-e] (f) Excite the SG coil 3 and close the stationary latch 8. [Status shown in Figure 2 b-f] (g) Demagnetize the MG coil 2 and release the movable grip 7. [Status shown in Figure 2 b-g] (h) Repeat the operations from b to g.

As mentioned above, the insertion or withdrawal of control rods into the reactor is performed by the SG coil of the control rod drive mechanism.
This is done by sequentially supplying direct current to three types of coils: the MG coil and the lift coil.
When the control rod is not driven, it is held in a fixed position by continuing to excite the SG coil.
It is important to note here that when the control rods are not driven [Fig. 2 a and b-i], the control rods will fall into the reactor unless the SG coil is energized.

The control rod controller supplies direct current to the three types of coils in the control rod drive mechanism. Conventionally, there has been a device of this type as shown in FIG. In the figure, loads 10, 20, and 30 correspond to the three types of coils of the control rod drive mechanism described above, respectively. That is, the load 10 corresponds to the SG coils of the plurality of control rod drive mechanisms, the load 20 corresponds to the MG coils of the plurality of control rod drive mechanisms, and the load 30 corresponds to the MG coils of the plurality of control rod drive mechanisms.
corresponds to the lift coils of multiple control rod drive mechanisms. Each load consists of three groups of loads. That is, the first
The set of loads 10 consists of a first group 12, a second group 14 and a third group 16 of SG coils. These three groups 12,
14 and 16 are all at the same level (SG
When holding the control rods by exciting the coils, a DC sequence is required to drive the control rods sequentially in groups, but in order to hold the control rods in a fixed position even during periods when the control rods are not driven, all control Since it is necessary to energize the SG coil of the rod drive mechanism,
It is not switched like the second and third sets of loads.

Similarly, for the second group of loads 20, the first group 22, the second group
It consists of a group 24 and a third group 26 of MG coils.
The loads in each of these three groups all still require the same level of DC sequence, but with different excitation periods.

That is, all three groups of control rods are driven, but their driving times are different. Therefore, the first group of control rods is driven by a first group of control rod drive mechanisms including a first group of SG coils, a first group of MG coils, and a first group of lift coils. The control rods of the second group are
It is driven by a second group control rod drive mechanism with a group of SG coils, MG coils and lift coils. Similarly, the third group of control rods is driven by a third group of control rod drive mechanisms.

The drive sequence for each group of control rods is as described above.
This is done by sequentially energizing three types of coils in each control rod drive mechanism.

Three phase power is provided by a three phase power supply 40 to a plurality of power units 42, 46, 50, 52 and 54. The power unit provides a DC output at predetermined multi-level (usually three-level) values based on a current reference signal from a current reference signal source to be described below. The first power unit 42 receives three phase power from a three phase power supply 40 through lines shown as a single line 44. The first power unit 42 is a power unit for providing a DC sequence to the lift coils of a plurality of control rod drive mechanisms. A second output from the three-phase power supply 40 is provided through line 48 to a second power unit 46. The second power unit 46 is a power unit for providing direct current to the MG coils of the plurality of control rod drive mechanisms. From the third output 49 from the three-phase power supply 46 to the lines 56,
Three phase power is supplied via 58 and 60 to three separate power units 50, 52 and 54, respectively. Power units 50, 52, and 54 are each a power unit for providing direct current to the SG coils of a plurality of control rod drive mechanisms in a predetermined sequence. The reason for having separate power units 50, 52 and 54 for each load 12, 14 and 16, respectively, is that during operation of the control rod drive, when a group of control rods is inserted or withdrawn, the remaining control rods are By energizing the SG coil of the group control rod drive mechanism,
This is because it is necessary to hold these control rods in a fixed position. For example, if the first group of control rod drive mechanisms is to be energized, i.e., the first group loads (SG coils) 12 of the first group 10, the first group loads (SG coils) of the second group 20, MG coil) 22 and 3rd
When the loads (lift coils) 32 of the first group of the set 30 are sequentially energized according to a predetermined DC sequence, the loads 14 and 16 of the second and third groups of the first set 10
This is because it is necessary to energize the control rods to prevent the control rods driven by these control rod drive mechanisms from falling into the reactor.

62 typically has three levels: zero current (the current that demagnetizes the coil), low current (the current required to hold the control rod), and full current (when the control rod is first driven). The current reference signal source 62 is a well-known current reference signal source that generates a current reference signal having a required current value) in a predetermined sequence.
Direct current is supplied from each power unit to various loads in response to a current reference signal supplied from the power unit. Current reference signal source 62 provides a first current reference signal to first power unit 42 via line 64. A first current reference signal is used to regulate the DC output from the first power unit 42, ie, the power unit for the lift coil of the control rod drive mechanism. DC output from the first power unit 42 is transmitted to any one of the first, second and third groups of loads 32, 34 and 36 via lines 78, 80 and 82, respectively. , the output from the first power unit 42 is selected by a first switching circuit 66 (eg, controlled by an external bank selection circuit).

Similarly, a second current reference signal from current reference signal source 62 is supplied via line 74 to second power unit 46, which is a power unit for the MG coils of the plurality of control rod drive mechanisms. The DC output from this second power unit 46 is supplied to a second switching circuit 76, and the first, second, and third groups of loads are switched in response to a second current reference signal from a current reference signal source 62.
Direct current is supplied to any one of 2, 24 and 26 via lines 68, 70 and 72, respectively.

The current reference signal 62 is routed by lines 84, 86 and 88 to three separate third current reference signals 100-1, 100 to third power units 50, 52 and 54, which are power units for the SG coils, respectively. -2 and third current reference signal 100-
3 respectively (however, the same signals 100-1 to 1
00-3, a current reference signal of the same DC level is supplied in the holding state). The third current reference signal 100-1 to these three power units
The reason why ~100-3 is supplied individually is that when a group of control rods is inserted or withdrawn, the SG coils of the control rod drive mechanisms of the remaining control rod groups are energized to keep these control rods constant. This is because it is necessary to hold it in position. The first and second power units may be constructed as thyristor converters, and the first and second switching circuits may also be constructed as thyristor switch devices.

Conventional equipment is configured as described above, so if the excitation function of the SG coil is lost in the control rod standby state, the stationary latch opens and the control rod drive shaft cannot be held, causing the control rod to The drawback was that it could fall into the core of a nuclear reactor, potentially causing the reactor to shut down.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and in the standby state, the control rod is held by both the stationary latch and the movable latch, so that the excitation function of the SG coil is lost. The object of the present invention is to provide a device that can continue operating a nuclear reactor by holding control rods using a movable latch even if the stationary latch opens.

In order to achieve such an object, the reactor control rod control device according to the present invention includes: a plurality of predetermined groups of lift coils; a switching circuit that sequentially selects one group of lift coils from the plurality of predetermined groups in a predetermined sequence; and a three-phase a first power unit that converts the power source into a direct current having a level based on a first current reference signal of a current reference signal source that sequentially generates a plurality of reference levels, and supplies this to a group of lift coils via the switching circuit; ; Movable gripper coils in the same number of groups as the predetermined plurality of groups; provided corresponding to the movable gripper coils in the predetermined plurality of groups, and connecting the three-phase power supply to the predetermined sequence from the current reference signal source. and second current reference signals 9 each prepared individually.
8-1 to 98-3, and a second power unit that converts the DC currents into DC currents of levels based on 8-1 to 98-3, respectively, and supplies the same to the predetermined plurality of groups of movable gripper coils; and stationary gripper coils; provided corresponding to the plurality of predetermined groups of stationary gripper coils, each of which has the predetermined sequence from the current reference signal source to the three-phase power supply; a third power unit that converts each of the third current reference signals 100-1 to 100-3 into DC currents at a level based on the third current reference signals 100-1 to 100-3 and supplies the same to the plurality of predetermined groups of stationary grip coils, respectively; Insertion and withdrawal operations of a group of control rods are performed via each of the power units based on the first, second, and third current reference signals, and the second and third current reference signal groups other than the insertion and withdrawal operations are performed. The present invention is characterized in that the movable gripper coil and the stationary gripper coil are energized via the second and third power units, respectively, outside of the insertion/extraction operations.

The present invention will be described below with reference to the embodiment shown in FIG. 4 of the accompanying drawings.

The difference in FIG. 4 from FIG. 3 is that another second power unit 90 and 92 are newly provided, and these are the loads of the second group 24 and third group 26 of the second group 20, respectively. (MG coil) is supplied with a DC sequence. Note that these second power units are also connected to the three-phase power supply 40 and the current reference signal source 62, as in the case of the third power unit. In other words, the difference from the conventional device shown in FIG. 3 is that the second multiplexer 76 shown in FIG. unit 4
6, 90 and 92 to the second set of loads 20
The structure was designed so that it can be supplied to For this reason, the second power units 46, 90 and 92 are supplied with three second current reference signals 98-1 to 98-3 having a predetermined sequence in order to synchronize the groups, as in the case of the third power unit. are tracks 74, 94, 96 respectively.
It is input by.

Control rod holding state (for example, Figure 2 a and b-a)
In the conventional device, the first set of 10 loads (SG
DC holding current was supplied only to the coil), but
In the device of the present invention, the configuration of the second power units 46, 90 and 92 is changed to the configuration of the third power units 50, 52 and 5.
4, the DC holding current is also supplied to the load (MG coil) of the second set 20 at the same time, and the control rod drive shaft 6 (Fig. 1) is connected to the stationary latch 8 (Fig. 1). It is held by both movable latches 7 (FIG. 1). The reason why separate second power units 46, 90, and 92 are provided for each load 22, 24, and 26 is that the MG coil Also, during operation of the control rod drive mechanism (Figure 1), when one group of control rods is inserted or withdrawn, the control rod drive mechanism of the remaining group
This is because the intention is to keep the MG coil energized.

Therefore, even if the third power unit 50, 52 or 54 fails and the stationary latch 8 attempts to open, the control rod will not fall because the movable latch 7 is closed. Furthermore, even if the second power unit 46, 90 or 92 fails and the movable latch attempts to open, the control rod will not fall because the stationary latch 8 is now closed.

As described above, according to the present invention, in the control rod standby state, both the SG coil and the MG coil are energized and the control rod is held by both the stationary latch and the movable latch. This has the effect of preventing critical control rods from falling and preventing unplanned reactor shutdowns.

[Brief explanation of drawings]

Figure 1 is a schematic sectional view of a control rod drive mechanism in a nuclear reactor, Figures 2a and b are diagrams showing the operation sequence of the control rod drive mechanism, Figure 3 is a block diagram of a conventional reactor control rod drive mechanism, FIG. 4 is a block diagram of a nuclear reactor control rod control device according to an embodiment of the present invention. In the figure, 10 is the first set of loads (SG coil),
20 is the second set of loads (MG coil), 30 is the third set of loads (lift coil), 40 is the three-phase power supply, 42 is the first power unit, 46, 90 and 92 are the second power unit, 50, 52 and 54 is a third power unit, 62 is a current reference signal source, 66 is a switching circuit,
12, 22 and 32 are first group loads, 14, 24 and 34 are second group loads, and 16, 26 and 36 are third group loads.
group load, 98 is the second current reference signal, 100 is the third
This is a current reference signal. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1 A plurality of predetermined groups of lift coils; a switching circuit that sequentially selects one group of lift coils among the plurality of predetermined groups in a predetermined sequence; a first current of a current reference signal source that sequentially generates a plurality of reference levels from a three-phase power supply; a first power unit that converts the DC current to a level based on the reference signal and supplies it to a group of lift coils via the switching circuit; movable gripper coils in the same number of groups as the predetermined plurality of groups; are provided corresponding to each of the movable gripper coils, and connect the three-phase power source to a direct current source having the predetermined sequence from the current reference signal source and having a level based on the individually prepared second current reference signal. a second converting current into a current and supplying the current to each of the predetermined groups of movable gripper coils;
a power unit; and stationary gripper coils in the same number of groups as the predetermined plurality of groups; provided corresponding to the stationary gripper coils in the predetermined plurality of groups, respectively, and connecting the three-phase power supply to the power supply reference signal source. a DC current having the predetermined sequence from three power units;
Insertion and withdrawal operations of a group of control rods are performed via each of the power units based on the second and third current reference signals, and the second and third current reference signals other than the insertion and withdrawal operations are used to perform insertion and withdrawal operations. Said second outside
and a third power unit, the movable gripper coil and the stationary gripper coil are energized, respectively.