JPH043517B2 - - 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 control rods 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 in.

FIG. 1 shows a simplified structure of a magnetic jack type drive mechanism for nuclear reactor control rods. In the figure, a lift coil 1 and a move valve gripper coil (hereinafter referred to as
Three coils, a stationary gripper coil (hereinafter referred to as an SG coil) 2 and a stationary gripper coil (hereinafter referred to as an SG coil) 3, operate an exemplary armature housed in the reactor pressure vessel. That is, the movable gripper armature 4 and the stationary gripper armature have latches 7 and 8 that engage with the valleys or grooves 6a of the control rod drive shaft 6 when the MG coil 2 and the SG coil 3 are energized, respectively. operate. 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 raises the control rod drive shaft 6 (moves in the withdrawal direction) and lowers it (moves it in the insertion direction). used for moving). 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 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 and the stationary latch 8 is closed, holding the control rod drive shaft [states shown in Figure 2 a-b] (b) MG Energize coil 2 and move movable latch 7
[Conditions shown in Figure 2 a-b] (c) Demagnetize the SG coil 3 and release the stationary latch 8 [states shown in Figure 2 a-c] (d) Energize the lift coil 1 The lift armature 9 is operated to raise the movable gripper armature 4. This causes the movable latch 7 to rise.
Raise the control rod drive shaft 6 indicated by 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 release the stationary. 8 [state shown in Figure 2 a-e] (F) Demagnetize the MG coil 2 and close the movable latch 7
[Conditions shown in Figure 2 a-c] (G) Demagnetize the lift coil 1 and lower the lift armature 9 in the direction of the arrow [Conditions shown in Figure 2 a-g] (chi) (b) Repeat the steps from (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 is held [states shown in Figure 2 b-a] (b) Energize the lift coil 1 to raise the lift armature 9 in the direction of the arrow [states shown in Fig. 2 b-b] (c) Energize the MG coil 2 and close the movable latch 7 [Fig. 2 b] -Condition C] (D) Demagnetize the SG coil 3 and release the stationary latch 8 (Condition shown in Figure 2 b-D) (E) Demagnetize the lift coil 1 and release the lift armature 9. lower the movable gripper armature 4. This lowers the control rod drive shaft 6 by one groove 6a in the direction of the arrow [state shown in Fig. 2 b-e] (f) SG coil 3 and close the stationary latch 8 [state shown in Fig. 2 b-g] (g) Demagnetize the MG coil 2 and release the movable latch 7 [state shown in Fig. 2 b-g] (H) Repeat operations from (B) to (G).

As mentioned above, the control rod drive mechanism's SG coil,
This is done by sequentially supplying direct current to three types of coils: the MG coil and the lift coil, and when the control rod is not being driven, it is held in a fixed position by continuing to excite the SG coil. Here, when the control rod is not driven [Fig. 2 a and b
-B] It is important to note that if the SG coil is not energized, the control rods will fall into the reactor.

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,
Loads 14 and 16 all require a DC sequence at the same level (when the SG coil is excited to hold the control rods), and the control rods are driven sequentially by group, but even during periods when the control rods are not driven, the control rods are Since it is necessary to energize the SG coils of all control rod drive mechanisms in order to hold the control rods in a constant position, they are 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 control signals from a control 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. The second from the three-phase power supply 40
The output of
supplied to 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. A third output from the three-phase power supply 40 is routed from line 49 to lines 56 and 5, respectively.
Three phase power is supplied via 8 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 This is because it is necessary to energize the SG coil of the group control rod drive function to hold these control rods in a fixed position. For example, if the first group of control rod drives is to be energized, i.e. the first group 10
1st group load (SG coil) 12, 2nd group 20
The first group of loads (MG coil) 22 and the third group 3
When the loads (lift coils) 32 of the first group 0 are sequentially energized according to a predetermined DC sequence, the loads 14 and 16 of the second group and the third group of the first group 10 are energized and their control is performed. This is because it is necessary to prevent the control rods driven by the rod drive mechanism from falling into the reactor.

62 typically has three levels from each power unit: zero current value (small current value that demagnetizes the coil), low current value (medium current value required to hold the control rods), and full current value (control rod hold current value). This is a well-known control signal source that generates a control signal in a predetermined sequence to control the conduction angle of a thyristor, for example, in order to output a DC current of a large current value (necessary only when driving the thyristor for the first time). According to each control signal supplied from 62, direct current of the various current values described above is supplied from each power unit to various loads.
Control signal source 62 provides a first control signal to first power unit 42 via line 64 . A first control 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. Direct current output from the first power unit 42 is routed to any one of the first, second, and third groups of loads 32, 34, and 36 via lines 78, 80, and 82, respectively. Additionally, 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 control signal from the control signal source 62 is transmitted to a line 74 to a second power unit 46, which is a power unit for the MG coils of the plurality of control rod drive mechanisms.
Supplied via. This second power unit 46
The DC output from is supplied to the second switching circuit 76,
the first control signal in response to the second control signal from the control signal source 62.
Group, second group and third group loads 22, 24 and 26
to any one of the lines 68 and 70, respectively.
and 72 to supply direct current.

Control signal source 62 provides three separate third control signal signals on lines 84, 86 and 88 to third power units 50, 52 and 54, respectively, which are power units for the SG coils. The reason why separate third control signals are supplied to these three power units 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. This is because it is necessary to hold these control rods in a fixed position. Furthermore, the first and second
and the third power unit may be constructed as a thyristor converter, 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 while the control rod is on standby, the control rod drive shaft cannot be held, and the control rod may fall. had the disadvantage of causing the reactor to shut down.

This invention was made to eliminate the drawbacks of the conventional ones as described above, and when the excitation function of the SG coil by the main power unit is lost, the failure detection section, the auxiliary power unit, and the first and second auxiliary switching The object of the present invention is to provide a device that can selectively excite an SG coil and an MG coil simultaneously and hold a control rod using a circuit. That is,
Duplicate the example functions of SG coil and MG coil,
It is a highly reliable device.

In order to achieve such an object, the nuclear reactor control rod control device according to the present invention includes a control rod drive mechanism having three types of coils: a stationary gripper coil, a movable gripper coil, and a lift coil, and a control rod drive mechanism having three types of coils: a stationary gripper coil, a movable gripper coil, and a lift coil; In a nuclear reactor control rod control device equipped with a control rod control device that supplies a current that excites a seed coil, a failure detection unit that detects an abnormality in the current supplied to the stationary gripper coil, and this failure detection unit. The apparatus further includes an auxiliary power unit that supplies current to excite the stationary gripper coil and the movable gripper coil when the abnormality is detected by the stationary gripper coil.

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

4 differs from FIG. 3 in that a failure detection section 90, an auxiliary power unit 41, a first auxiliary switching circuit 91, and a second auxiliary switching circuit 100 are provided. The failure detection section 90 connects the output lines 92, 94 and 96 of the third power units 50, 52 and 54.
connected to input the output current from the The failure detection unit 90 is further connected to an auxiliary power unit 41 connected to the three-phase power supply 40 and a first auxiliary switching circuit 91 connected between these and the SG coil loads of any group. ,
A second auxiliary switching circuit 10 connected between the auxiliary power unit 41 and the MG coil load of either group.
It is also connected to 0. When the failure detection circuit 90 detects an abnormality in the output current value of any of the third power units 50, 52, and 54, for example, when a failure occurs in which no current flows, the failure detection circuit 90 starts up the auxiliary power unit 41 and simultaneously switches on the first auxiliary switching circuit. 91 and the second auxiliary switching circuit 100, the third power units 50, 52,
and 54 is abnormal, and thereby the first auxiliary switching circuit 91 changes the output point 98 of the auxiliary power unit 41 to the SG of the group corresponding to the failed power unit 50, 52, or 54.
In addition to switching the connection to the coil load 12, 14, or 16, the second auxiliary switching circuit 100 connects the output point 98 of the auxiliary power unit 41 to the same group as the group corresponding to the failed power unit 50, 52, or 54.
It is selectively connected to the MG coil load 22, 24, or 26. Incidentally, as the auxiliary power unit 41, the third
A thyristor type provided for backup of the power unit can be used, and although it is functionally almost the same as the third power unit, it has a constant voltage control circuit configuration that is simpler than the constant current control circuit configuration. Therefore, the control signal from the control signal source 62 is not used. Further, the first and second auxiliary switching circuits 91 and 100 are also similar to the first and second switching circuits.
It may also be configured as a thyristor type switch device.

With this system, the control rod insertion and withdrawal functions are no different from the conventional system, but
When the excitation function of the SG coil holding the control rod is lost, this is detected and the auxiliary power unit 4
SG coil and MG belonging to the same group according to 1.
It has a unique function of preventing the control rod from falling by energizing the coil.

For example, if the third power unit 50 fails and the
When the current necessary for holding the control rods is no longer supplied to the SG coil load 12 of the first group of group 10, the failure detection unit 90 detects an abnormality, that is, the absence of this power, from the output line 92, Failure detection section 90
assists the three-phase power supply so that the power supplied from the three-phase power supply 40 via the line 45 excites the first group of SG coil loads 12 and MG coil loads 22 corresponding to the failed power unit. It instructs the power unit 41 to rectify and to switch the output line 98 of the auxiliary power unit 41 to the output line 92 and the output line 68 by the first and second auxiliary switching circuits 91 and 100, respectively. Therefore, even if the third power unit 50 fails and the stationary latch 8 (FIG. 1) attempts to open, the auxiliary power unit 41 replaces the third power unit 50 and operates the first set 10 and the second set 20. In order to supply the current necessary for holding the control rod to the SG coil 12 and MG coil 22, which are the loads of the first group, the control rod is held at a fixed position without falling.

It goes without saying that even if a failure occurs in the third power unit 52 or 54, the control rods of the second group and the third group, respectively, can be maintained in the states shown in FIGS.

As described above, according to the present invention, the first set of SG
The abnormal state of the current supplied to the coil load 10 is monitored, and if there is an abnormality, the auxiliary power unit 41
Since the excitation current is supplied to the first set of loads 10 and the second set of loads 20, it is possible to prevent unnecessary control rods from falling and prevent 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 control rod control device, and Figure 3 is a block diagram of a conventional control rod control device. FIG. 4 is a block diagram of a 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 a second set of loads (MG coil), 30 is a third set of loads (lift coil), 40 is a three-phase power supply, 42 is a first power unit, 46 is a second power unit, 5
0, 52, and 54 are third power units; 62 is a control signal source; 66 is a first switching circuit; 76 is a second switching circuit; 12, 22, and 32 are first group loads;
4, 24, and 34 are the second group loads; 16, 26,
and 36 are third group loads, 41 is an auxiliary power unit, 90 is a failure detection section, 91 is a first auxiliary switching circuit, and 100 is a second auxiliary switching circuit. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A control rod drive mechanism that has three types of coils: a stationary gripper coil, a movable gripper coil, and a lift coil, and a control rod control that supplies current to excite these three types of coils. A reactor control rod control device comprising: a failure detection unit that detects an abnormality in the current supplied to the stationary gripper coil; and when the failure detection unit detects the abnormality, A nuclear reactor control rod control device, further comprising an auxiliary power unit that supplies current to excite the stationary gripper coil and the movable gripper coil.