JPH06186391A - Nuclear power plant - Google Patents

Abstract

PURPOSE:To provide a nuclear power plant capable of performing control of reactor pressure in a nuclear reactor with a turbine bypass valve and contriving improvement of safety even in the case where abnormality occurs in a high pressure oil pump, a control oil feeding line and the like. CONSTITUTION:In addition to a high pressure oil pump 31 a control oil pup for turbine bypass valve drive 101 in a stop state at the time of normal operation is set in an oil tank 30. A discharge line of the control oil pump for the turbine bypass valve drive 101 is connected to the secondary side of a check valve 33 set on the discharge line of the high pressure oil pump 31 via another check valve 102. Furthermore a pressure detector 103 is set on a control oil feeding line for a turbine bypass line 16 on which an accumulator 34 is set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear power plant having a turbine bypass system that guides steam generated in a nuclear reactor to a condenser by bypassing the turbine, and particularly to a high pressure control oil boosted by a high pressure oil pump. Relates to a nuclear power plant that drives a steam valve that controls the steam flow.

[0002]

2. Description of the Related Art FIG. 3 schematically shows a conventional turbine system of a nuclear power plant. During normal operation, the steam generated in the reactor 1 flows into the high-pressure turbine 5 via the main steam isolation valve 2, the main steam stop valve 3, and the steam control valve 4.
The high pressure turbine 5 is rotated. At this time, based on the signals of the main steam pressure detected by the pressure detector 6, the turbine speed detected by the speed detector 7, and the system load 8, the steam control valve 4
The main steam pressure and the amount of steam flowing into the high pressure turbine 5 are controlled by.

The steam discharged from the high-pressure turbine 5 passes through the combination intermediate valves 9 and 10 to the low-pressure turbine 11,
12 to rotate the low pressure turbines 11, 12.
As a result, the power generator 13 coupled to the turbine shaft system rotates and power is generated. The steam discharged from the low-pressure turbines 11 and 12 flows into the condenser 14, is condensed, and is then supplied to the reactor 1 again by the feed water pump 15.

On the other hand, when the steam flowing into the turbine is cut off by cutting off the load, the steam control valve 4 is closed rapidly,
In order to prevent the main steam pressure before the inlet of the main steam stop valve 3 from rising by this, the turbine bypass valve 16 is rapidly opened and controlled so that the main steam pressure is kept constant. The steam exiting the turbine bypass valve 16 flows into the condenser 14 via the temperature reducing / pressure reducing device 17.

On the other hand, control oil is stored in the oil tank 30 and is pressurized by the high-pressure oil pump 31, and then supplied to the hydraulic cylinders of the main steam stop valve 3, the steam control valve 4, and the combination intermediate valves 9 and 10. And is thereby configured to drive each valve. The accumulator 32 is installed in order to mitigate the transient hydraulic pressure fluctuation of the control oil supply line that occurs when the valve rapidly opens and closes, such as the rapid closing of the steam control valve 4 as described above.

The control oil supply line is partially branched and supplied to the hydraulic cylinder of the turbine bypass valve 16 via the check valve 33. On the secondary side of the check valve 33,
Since the accumulator 34 is installed, the transient oil amount required to drive the hydraulic cylinder when the turbine bypass valve 16 is suddenly opened is secured.

Drain oil is generated from each hydraulic cylinder of each steam valve described above, and these drain oils are collected by the drain line and collected in the oil tank 30 via the oil cooler 35. The oil level of the control oil in the oil tank 30 is monitored by the liquid level gauge 36.

It is the steam valves including the steam control valve 4 that directly control the turbine speed, the turbine load and the main steam line pressure, and the high pressure for supplying the control oil for driving to these steam valves. The oil pump 31 is required to have high reliability. Therefore, in general, the high pressure oil pump 31 is
In the case where an abnormality occurs during operation of one of the high-pressure oil pumps 31 and the hydraulic pressure necessary to drive and control the steam valve is unlikely to be ensured, it is detected in advance and the other stopped The high-pressure oil pump 31 is started to secure the required hydraulic pressure.

[0009]

However, since the high-pressure oil pump is constantly operated, an AC power source drive type motor is used as its driving electric motor.
If the AC power supply is temporarily stopped due to some accident, or if the control oil supply line that supplies high-pressure oil is damaged or damaged and the control oil pressure drops sharply, It is possible to lose control of the steam valve.

Particularly, when the control oil pressure for driving the hydraulic cylinder of the turbine bypass valve is abnormally lowered, the turbine bypass valve is fully closed, and the pressure of the main steam line, that is, the reactor pressure inside the reactor cannot be controlled. And may rise abnormally. If the reactor pressure inside the reactor rises abnormally in this way, the reactor pressure should be gradually reduced over a sufficient period of time so that each function inside the reactor is not impaired. It is necessary to stop the output.

The present invention has been made in consideration of such conventional circumstances. Even when an abnormality occurs in the high-pressure oil pump, the control oil supply line, etc., the turbine bypass valve allows the reactor pressure in the reactor to be reduced. The present invention is intended to provide a nuclear power plant that can perform the above control and can improve safety.

[0012]

That is, a nuclear power plant according to the present invention has a turbine bypass system for guiding steam generated in a nuclear reactor to a condenser by bypassing the turbine,
Supplying the control oil to a hydraulic drive device that drives a turbine bypass valve that controls the steam flow rate of the turbine bypass system, in a nuclear power plant that drives a steam valve that controls the steam flow rate by the control oil that has been boosted by a high-pressure oil pump A pressure detector is installed in the hydraulic pressure supply line, and a control oil pump for driving a turbine bypass valve, which is activated based on a pressure drop signal from the pressure detector and sends control oil to the hydraulic drive device, is installed. Characterize.

[0013]

In the nuclear power plant of the present invention having the above structure,
When an abnormality occurs in the high-pressure oil pump and control oil supply line, etc., and the pressure in the hydraulic supply line drops, this pressure drop is detected by the pressure detector and the turbine bypass valve drive control oil pump is started by the pressure drop signal. Thus, the control oil pressure of the turbine bypass valve can be secured, and the reactor pressure in the reactor can be controlled by the turbine bypass valve.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a nuclear power plant according to an embodiment of the present invention. The same parts as those of the conventional nuclear power plant shown in FIG. 3 are designated by the same reference numerals.

In the nuclear power plant of this embodiment, the oil tank 30 is provided with a high-pressure oil pump 31 and a turbine bypass valve drive control oil pump 101 which is stopped during normal operation. The discharge line of the control oil pump 101 for driving the turbine bypass valve includes the check valve 10
2 is connected to the secondary side of the check valve 33 installed in the discharge line of the high-pressure oil pump 31. A pressure detector 103 is installed in the control oil supply line to the turbine bypass valve 16 in which the accumulator 34 is installed.

Here, in general, the water supply pump 15 is driven by a turbine drive system that utilizes the energy of an auxiliary steam system that uses a part of the main steam line as a source during normal operation, but the output of the plant is small. When the energy of the auxiliary steam system is not sufficiently supplied, water is supplied to the reactor 1 by an electric motor driven water supply pump (not shown) by an AC power source. In the nuclear power plant of the present embodiment, independently of this, an auxiliary pump 104 for water supply of an electric motor drive by an emergency power source is installed in parallel with the water supply pump 15. The auxiliary pump 104 is a relatively small pump having a capacity capable of performing partial load water supply such that the reactor 1 does not scram.

In the nuclear power plant of this embodiment having the above-described structure, during normal operation of the plan, the control oil boosted by the high-pressure oil pump 31 from the oil tank 30 in which the control oil is stored is indispensable for controlling the turbine. It is supplied to the hydraulic cylinders of the main steam stop valve 3, the steam control valve 4, the combination intermediate valves 9 and 10, and the turbine bypass valve 16, thereby driving each valve.

As described above, in the normal case, the high pressure oil pump 31 is duplicated. Here, when an abnormality occurs in these high-pressure oil pumps 31 or the AC power supply of the driving motor of the high-pressure oil pump 31 fails and the power supply function is lost, the high-pressure oil pump 31 is used for control. The pressure increasing function of is lost, and the hydraulic pressure of the control oil supply line drops sharply.

Therefore, the main steam stop valve 3 excluding the turbine bypass valve 16, the steam control valve 4, the combination intermediate valves 9, 10
The hydraulic cylinder's drive capability is lost and these steam valves trip. With respect to the turbine bypass valve 16, the control oil pressure is secured for a certain period of time by the function of the check valve 33.

Here, when the pressure detected by the pressure detector 103 becomes equal to or lower than "the oil pressure required to drive the turbine bypass valve 16 + the predetermined value", the turbine bypass valve is detected based on this pressure drop detection signal. The drive control oil pump 101 automatically starts and starts supplying control oil to the turbine bypass valve 16. Thereby, only the turbine bypass valve 16 can be continuously driven, and the reactor pressure in the reactor 1 can be controlled. At this time, the steam flows into the condenser 14 via the turbine bypass valve 16 and the temperature reducing / pressure reducing device 17.

Since the control oil pump 101 for driving the turbine bypass valve is used for controlling the drive of only the turbine bypass valve 16, its capacity is smaller than that of the high-pressure oil pump 31, and the capacity of the driving electric motor is also small. , Its driving energy can be fully covered by the emergency power supply.

Further, in the nuclear power plant according to the present embodiment, since the auxiliary pump 104 for supplying water of the electric motor drive system by the emergency power source is provided, even if the AC power source fails, the condenser 14 is connected to the reactor. Water can be supplied to the reactor 1. Therefore, the reactor output is stopped for a sufficient time so that the functions of the reactor 1 are not impaired without sharply reducing the reactor pressure in the reactor 1. Can be made.

As described above, the auxiliary pump 104 has an ability to supply a partial load of water so that the reactor 1 does not scram, and the capacity of the drive motor is relatively small. The power source can sufficiently cover the driving energy. Further, the control oil pump 101 for driving the turbine bypass valve and the auxiliary pump 104 may be of a motor drive system using an AC power supply, and the AC power supply may be connected to a backup power supply of a diesel power generation system or the like. Even in this case, since the turbine bypass valve drive control oil pump 101 and the auxiliary pump 104 have smaller capacities than the high-pressure oil pump 31 and the water supply pump 15, respectively, the ratio of the load applied to the backup power source is small. Next, a nuclear power plant according to another embodiment will be described with reference to FIG. In FIG. 2, the same parts as those in FIGS. 1 and 3 are designated by the same reference numerals.

Below the oil tank 30, the oil tank 3
The sub-tank 201 is installed independently of 0, the oil tank 30 and the sub-tank 201 are connected by a connecting pipe 202, and normally, the sub-tank 201 is configured to be filled with control oil. .

Further, the sub-tank 201 is provided with a turbine bypass valve drive control oil pump 101 which is stopped during normal operation. The discharge line of the control oil pump 101 for driving the turbine bypass valve is connected to the secondary side of the check valve 33 installed in the discharge line of the high-pressure oil pump 31 via the check valve 102. Also,
Turbine bypass valve 1 with accumulator 34 installed
A pressure detector 103 is installed in the control oil supply line to the control unit 6.

Further, an auxiliary pump 104 for supplying water of an electric motor driving system of an emergency power source is installed in parallel with the water supplying pump 15 independently of an electric motor driving water supply pump of an AC power source (not shown). There is. This auxiliary pump 1
Reference numeral 04 is a relatively small pump having a capacity capable of performing partial load water supply such that the reactor 1 does not scram.

In the nuclear power plant of this embodiment having the above-described structure, during normal operation of the plant, the control oil boosted by the high-pressure oil pump 31 from the oil tank 30 in which the control oil is stored is the steam valve. Supplied to hydraulic cylinder.

Here, the inside of the control oil line on the discharge side of the high-pressure oil pump 31 is normally in a high pressure state, and there is a possibility that the control oil will leak to the outside from the control oil supply pipe and joints. When such a control oil leak occurs, the oil level of the oil tank 30 gradually lowers from the standard oil level A shown in FIG. 2, and when it reaches the vicinity of the suction pipe level B of the high-pressure oil pump 31, the high-pressure oil pump 31 Cavitation occurs and the control oil supply is lost. As a result, the driving ability of the hydraulic cylinders of the steam valves other than the turbine bypass valve 16 is lost, and the steam valves are fully closed.

Here, when the oil level of the oil tank 30 is lowered and the oil level detected by the liquid level gauge 36 becomes equal to or lower than the preset oil level, this detection signal causes the control oil pump for driving the turbine bypass valve. 101 is automatically started. Thereby, the control oil can be supplied only to the turbine bypass valve 16, the turbine bypass valve 16 can be driven, and the reactor pressure in the reactor 1 can be controlled.

Further, as in the above-described embodiment, the pressure detected by the pressure detector 103 installed in the control oil supply line of the turbine bypass valve 16 is "the hydraulic pressure required to drive the turbine bypass valve 16". + "Predetermined value" or less, turbine bypass valve drive control oil pump 101
Is automatically started, and the supply of control oil to the turbine bypass valve 16 is started. As a result, only the turbine bypass valve 16 can be continuously driven, and the reactor 1
The furnace pressure inside can be controlled.

Further, since the auxiliary pump 104 for supplying water of the electric motor drive system using the emergency power source is provided, water can be supplied from the condenser 14 to the reactor 1 even if the AC power source fails. As a result, it is possible to stop the reactor power for a sufficient period of time so as not to impair the functions of the reactor 1 without abruptly reducing the reactor pressure in the reactor 1.

[0032]

As described above, according to the nuclear power plant of the present invention, even when an abnormality occurs in the hydraulic pressure generator or the control oil supply line for supplying the control hydraulic pressure to the steam valve for controlling the steam turbine, The turbine bypass system can be controlled to control the reactor pressure in the reactor, and safety can be improved compared to the conventional case.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a nuclear power plant according to an embodiment of the present invention.

FIG. 2 is a diagram showing the configuration of a nuclear power plant according to another embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a conventional nuclear power plant.

[Explanation of symbols]

 1 Reactor 5 High Pressure Turbine 11,12 Low Pressure Turbine 14 Condenser 15 Water Supply Pump 16 Turbine Bypass Valve 30 Oil Tank 31 High Pressure Oil Pump 36 Level Gauge 101 Turbine Bypass Valve Drive Control Oil Pump 102 Check Valve 103 Pressure Detector 104 Auxiliary pump

Claims (3)

[Claims] 1. A nuclear power system having a turbine bypass system for bypassing steam generated in a nuclear reactor to a condenser by bypassing a turbine, and driving a steam valve for controlling a steam flow rate by control oil boosted by a high-pressure oil pump. In a power plant, a pressure detector is installed in a hydraulic pressure supply line that supplies the control oil to a hydraulic drive device that drives a turbine bypass valve that controls the steam flow rate of the turbine bypass system,
A nuclear power plant comprising a control oil pump for driving a turbine bypass valve, which is activated based on a pressure drop signal from the pressure detector and sends control oil to the hydraulic drive device. 2. The nuclear power plant according to claim 1, wherein a sub-tank communicating with the oil tank is provided below the oil tank for storing the control oil, and the turbine bypass valve drive control oil is provided. The nuclear power plant, wherein the pump is configured to send control oil from the sub-tank to the hydraulic drive device in response to an oil level reduction signal from a liquid level sensor provided in the oil tank. 3. The nuclear power plant according to claim 1, wherein an auxiliary pump of an electric motor drive type that can be driven by a non-ride power supply is provided in parallel with a water supply pump that supplies water from the condenser to the reactor, A nuclear power plant, wherein water is supplied to a nuclear reactor by the auxiliary pump when a control oil pump for driving a turbine bypass valve is driven.