JPH07229995A - Pressure controller at the cold hot condition of reactor pressure vessel - Google Patents

Abstract

PURPOSE:To provide a pressure controller at the cold hot condition of a reactor pressure vessel for automatically conducting pressure control in a reactor pressure vessel based on the pressure, a water level signal and the like of the reactor pressure vessel in a cold hot state. CONSTITUTION:In a reactor provided with a drive water pump 5, a drive water control valve 7, a drive water flow detector 10 of a control rod drive system, a drain valve 8 and a drain flow detector 11 of a reactor water purification system, a water level detector 13, an exhaust valve 9 and a pressure detector 12 for a reactor pressure vessel 1, signals of a flow rate, pressure and a water level transmitted from the drive water flow detector 10, the drain flow detector 11, the pressure detector 12 and the water level detector 13 are provided, a control signal is output based on a predetermined program to the drive water control valve 7, the drain valve 8, the exhaust valve 9 and the drive water pump 5 respectively, and a pressure controller 18 for performing pressure control of the reactor pressure vessel 1 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water pressure test of a reactor pressure vessel at the time of periodic inspection in a nuclear power plant, and particularly to an atom for automatically controlling an arbitrary target value of water level and pressure in a cold state of the reactor pressure vessel. The present invention relates to a pressure control device for a cold state of a furnace pressure vessel.

[0002]

2. Description of the Related Art For nuclear power plants, it is legally necessary to regularly shut down the power plant and inspect the work (generally called periodic inspection). It is obligatory to have an inspection. Completion of inspection work including replacement of components inside the reactor pressure vessel (fuel, control rods, nuclear instrumentation, steam separator, steam dryer, etc.) to be carried out during this periodic inspection period, and reactor pressure vessel Confirmation of the soundness of restoration will be carried out at the completion of inspection work including replacement of auxiliary equipment (control rod drive mechanism, recirculation pump, piping valves, etc.).

To this end, the reactor pressure vessel is filled with water in a cold state of the reactor pressure vessel and pressurized by a pump. For example, a primary system inspection A, a leakage inspection B, and a control rod as shown in the process diagram of FIG. Work such as drive system functional inspections C and E, pump test D, and pre-use inspection F are performed.

Pressurization and pressure control for the water pressure test on the reactor pressure vessel at this time are performed by supplying water into the reactor pressure vessel through a cooling water line of the control rod drive system by a control rod drive water system pump. Then, the water is discharged from the reactor pressure vessel to the outside of the system through the blow line of the reactor cleaning system. In this pressure control, the operator adjusted the balance between the water supply amount and the water discharge amount while monitoring the reactor pressure.

In addition, following the primary inspection A and the leakage inspection B of the work process, the functional inspection C of the control rod drive system is carried out using the reactor pressure (operating pressure) in this reactor pressure vessel.
(All control rod scrum test) is also conducted. Furthermore, in recent years, early soundness confirmation (removal and early correction of faulty parts is required due to remodeling and renewal of peripheral equipment of reactor pressure vessels (for example, reactor recirculation pump parts, motors) and replacement of the control system. From the viewpoint of (including), there is a trial operation D under cold pressurization (operating pressure) of the reactor pressure vessel.

Each of the above confirmations and tests is critical in the process of the periodic inspection work, and the inspection of the government inspection target is an in-house inspection prior to the inspection. The opportunity to settle into a series of plant conditions occurs multiple times.

[0007]

The work of stabilizing the pressure of the reactor pressure vessel in a cold state of the reactor at a predetermined pressure is a major task depending on the size of the reactor pressure vessel and the work content. Of course, operation management of the equipment system related to the above-mentioned tests and inspections is also necessary for the progress.

Furthermore, while coping with an alarm generated abruptly during the test of the reactor pressure vessel, etc., the plant pressure, etc. There was a problem that the burden on the operator who prepares the state settling according to the planned process and manages the operation becomes very large.

An object of the present invention is to provide a cold pressure control device for a reactor pressure vessel, which automatically controls the pressure in the reactor pressure vessel from the pressure of the reactor pressure vessel and the water level signal in a cold state. To provide.

[0010]

In order to achieve the above object, a reactor pressure vessel cold temperature pressure control device according to the present invention comprises a drive water pump and a drive water regulating valve provided in a control rod drive system for controlling water supply. In a reactor equipped with a driving water flow rate detector and a drainage valve for controlling drainage provided in a reactor water purification system, a drainage flow rate detector, a water level detector provided in a reactor pressure vessel, an exhaust valve, and a pressure detector, Driving water flow rate detector, drainage flow rate detector, pressure detector, and water level signal from the water level detector are input respectively, and the driving water regulating valve, drainage valve, and exhaust valve are installed in accordance with a preset program. Further, a pressure controller for outputting a control signal to each of the driving water pumps to control the pressure of the reactor pressure vessel is provided.

[0011]

[Operation] Pressurization of the reactor pressure vessel and constant pressure control are automatically performed according to the operator's instruction in the cold state of the plant. (1) Water pressure is applied to the reactor pressure vessel in preparation for pressurization. The pressure controller controls the amount of water supplied by the drive water adjusting valve while comparing the water level signal from the water level detector with a preset target. When the water level reaches the target, the exhaust valve that had been open until then is closed and the pressure increase in the reactor pressure vessel is started.

(2) The pressure controller monitors and evaluates the rate of pressure increase from the pressure detectors at the start of pressurization, and controls the drive water regulating valve and the drain valve to control the supply and drainage amount to the reactor pressure vessel in advance. Hold the boost and constant pressure according to the set program. (3) During boosting / boosting or constant pressure control, if the pressure in the reactor pressure vessel rises above a preset pressure, such as when the drainage control valve is closed unexpectedly, pressure control is performed with the pressure signal from the pressure detector. The water supply automatically stops the water supply.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. As shown in the configuration diagram of FIG. 1, a reactor pressure vessel 1
A control rod drive mechanism 4 for changing (inserting, withdrawing) the position of the control rod 3 for adjusting the nuclear reactivity of the core 2 arranged in the core 2 is installed at the bottom of the control rod drive. The drive water pump 5 of the system 28 supplies water from the condensate storage tank 6 via the drive water regulating valve 7 for the purpose of driving and cooling the control rod drive mechanism 4.

The water supplied to the control rod drive mechanism 4 is discharged into the reactor pressure vessel 1 after passing through the control rod drive mechanism 4. In the reactor pressure vessel 1, unless the water discharged from the control rod drive mechanism 4 is discharged to the outside of the reactor pressure vessel 1, the water level in the reactor pressure vessel 1 rises. Further, if the air in the reactor pressure vessel 1 is not exhausted, the rise in the water level causes the space in the reactor pressure vessel 1 to be compressed and the pressure in the reactor pressure vessel 1 to rise.

Recirculation system attached to the reactor pressure vessel 1
In the reactor water purification system 23, which is branched from 26 and the other end of which is connected to the water supply pipe 27, a drainage system 24 for discharging excess water in the reactor pressure vessel 1 to the condensate storage tank 6 is provided via a drain valve 8. An exhaust system 25 for preventing pressure rise is provided at the top of the reactor pressure vessel 1 via an exhaust valve 9.

Further, a drive water flow rate detector 10 is provided in the flow path of the control rod drive system 28 having the drive water adjusting valve 7, and a drain water flow rate detector is provided in the flow path of the reactor water purification system 23 having the drain valve 8. 11 is,
The reactor pressure vessel 1 has a pressure detector 12 and a water level detector 13
Is provided. The drive water flow rate signal 14, drainage flow rate signal 15, pressure signal 16 and water level signal 17 output from each of the detectors 10, 11, 12, 13 are preset pressure increase, constant pressure, pressure drop, etc. according to the program. It is input to the pressure controller 18 which is a computerized program controller for processing.

From this pressure controller 18 to the drive water pump 5
Is a stop signal 19 and the drive water adjusting valve 7 is a drive water control signal.
20 and the drainage control signal 21 to the drainage valve 8 and the exhaustion control signal 22 to the exhaust valve 9 respectively.

Next, the operation of the above configuration will be described. (1) To prepare for boosting the pressure in the reactor pressure vessel 1, after the operator confirms that boosting for the entire plant has been confirmed, when the “pressurizing preparation mode” of the pressure controller 18 is started, the pressure controller 18 Starts to control the drive water adjusting valve 7 and the drain valve 8 so that the flow rate of water supplied to the reactor pressure vessel 1 becomes equal to the flow rate of drainage in accordance with a preset program. When this flow rate difference stabilizes within the allowable range, "preparation for boosting"
Then, it shifts to the next "pressure increase mode".

(2) For the pressure rise control, the pressure controller
18 is a "pressurization ready" (supply water flow rate = drainage flow rate), and the closing signal 22 is issued to the exhaust valve 9 on condition that the water level signal 17 is stable at a predetermined target value. Further, a deviation is calculated from the target value of pressure change over time in consideration of the planned pressurization time and the actual pressure, and the drainage control signal 21 starts the control to the drainage valve 8.

When the opening of the drain valve 8 is reduced, the amount of drainage decreases, and the water held in the reactor pressure vessel 1 increases, so that the pressure rises. The program target value that increases with time is tracked as an actual pressure due to the difference between the quantitative water injection into the reactor pressure vessel 1 and the controlled discharge amount.

(3) In the constant pressure control of the pressure, when the pressure signal 16 from the pressure detector 12 reaches a constant target value (within a predetermined allowable range), the pressure controller 18 stops changing the target value with time. Then, since the drainage control signal 21 is continuously output at a constant level, the drainage valve 8 is finally stabilized in a valve opening state in which the water supply flow rate from the control rod drive system 28 and the drainage flow rate become equal. This state is maintained until the next pressure increase to the target pressure value or the "pressure decrease mode" is issued.

(4) Regarding the pressure drop control, the pressure controller 18
The "pressure drop mode" is a program that considers the planned pressure reduction time, and controls the drainage valve 8 with respect to the target value of pressure change over time (in contrast to the case of boosting, the drainage valve 8 increases the opening degree). Increase the drainage) Follow it.

(5) Regarding ensuring safety during boosting and constant pressure control, if the drain valve 8 is completely closed unplanned for some reason, the pressure in the reactor pressure vessel 1 will increase due to an increase in water retained. It is assumed that the pressure rises and excessive pressure is applied to the reactor pressure vessel 1 and attached equipment.

However, when the pressure in the reactor pressure vessel 1 exceeds the preset pressure, the pressure controller
18 outputs a stop signal 19 to the driving water pump 5 to stop the water supply from the control rod drive system 28 into the reactor pressure vessel 1 and thereby prevent an excessive pressure from being applied to the reactor pressure vessel 1. .

In the present invention, conventionally, the reactor pressure vessel 1 at the time of the cold temperature of the plant was carried out by monitoring the experience and intuition of the operator and the state of the reactor pressure vessel 1 from beginning to end.
Since the step-up / step-down of the internal pressure and the constant value control are automatically performed, the burden on the operator is greatly reduced. Further, since the pressurization / depressurization and constant pressure control to the reactor pressure vessel 1 are automated and are not affected by individual differences in operator's operation, work stability and reproducibility are accurate, and high reliability is obtained. .

In particular, when it is necessary to repair the equipment in the pressure increase inspection during the periodic inspection, the work of "reduction step → repair → step up → inspection → step down" in the reactor pressure vessel 1 is required, and the cold state Although the frequency of performing the pressure control in step 1 increases, the present invention can easily perform the pressure control.

[0027]

As described above, according to the present invention, the pressurization, depressurization and constant pressure control of the internal pressure in the cold state of the reactor pressure vessel, which is carried out at the time of periodic inspection, etc., are automatically performed and the pressure control is performed. Is accurate and improves work reliability. further,
This has the effect of significantly reducing the burden on workers.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a cold pressure control device for a reactor pressure vessel according to an embodiment of the present invention.

FIG. 2 is a process diagram of a pressure test in a reactor pressure vessel.

[Explanation of symbols]

1 ... Reactor pressure vessel, 2 ... Reactor core, 3 ... Control rod, 4 ... Control rod drive mechanism, 5 ... Drive water pump, 6 ... Condensate storage tank,
7 ... Drive water adjusting valve, 8 ... Drain valve, 9 ... Exhaust valve, 10 ... Drive water flow rate detector, 11 ... Drainage flow rate detector, 12 ... Pressure detector,
13 ... water level detector, 14 ... driving water flow rate signal, 15 ... drainage flow rate signal, 16 ... pressure signal, 17 ... water level signal, 18 ... pressure controller, 19
… Stop signal, 20… Drive water control signal, 21… Drainage control signal,
22 ... Exhaust control signal, 23 ... Reactor water purification system, 24 ... Drainage system, 25 ...
Exhaust system, 26 ... Recirculation system, 27 ... Water supply piping, 28 ... Control rod drive system.

Claims (1)

[Claims] 1. A drive water pump, a drive water adjusting valve, a drive water flow rate detector, and a drainage valve and a drainage flow rate detector, which are provided in a control rod drive system, for controlling water supply, and a drainage flow rate detector, which is provided in a reactor water purification system. In a reactor equipped with a water level detector provided in a reactor pressure vessel, an exhaust valve, and a pressure detector, the flow rate and pressure from the driving water flow rate detector, the drainage flow rate detector, the pressure detector, and the water level detector, respectively. A pressure controller for inputting a water level signal and outputting a control signal to each of the drive water regulating valve, the drain valve, the exhaust valve, and the drive water pump according to a program prepared in advance to control the pressure of the reactor pressure vessel. A reactor pressure vessel cold temperature pressure control device characterized by being provided.