JP3457465B2 - Operating method and apparatus for cooling system during reactor isolation - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for operating a reactor isolation cooling system of a boiling water type light water reactor nuclear power plant.

[0002]

2. Description of the Related Art FIGS. 12 to 14 are schematic diagrams of a system such as a reactor isolation cooling system (hereinafter referred to as RCIC system) of an improved boiling water type light water reactor (hereinafter referred to as ABWR) nuclear power plant under start-up test. .

The purpose of this RCIC system is to supply cooling water to the reactor at the time of reactor isolation due to the loss of cooling water from the water supply system to cool the core and maintain the reactor water level.
Further, the ABWR is designed to be improved so as to serve as an emergency core cooling system in the case where the piping etc. is broken and the coolant in the reactor pressure vessel (hereinafter referred to as RPV) 1 is lost. The RPV 1 is stored in the reactor containment vessel 2,
A dry well 3 is formed in the reactor containment vessel 2, while a suppression pool (hereinafter referred to as S / P) 4 is built therein. The RPV 1 is connected to the water supply pipe 5 and the main steam pipe 6.

The RCIC system includes an RCIC pump 7, an RCIC turbine 8 for driving the RCIC pump 7, a set of turbine accessories, and piping, valves, and instrumentation control equipment required for system configuration.

The ABWR RCIC system has the following operating modes: reactor isolation mode, accident mode, and system test mode.

(1) Reactor isolation mode (see FIG. 12) When RPV1 is isolated, the reactor pressure rises and the relief safety valve operates to keep the reactor pressure below the set value. On the other hand, since the water supply is lost at this time, steam generation due to the decay heat of the fuel continues and the reactor water level continues to drop.

When the reactor water level drops and reaches a low water level (L-2), the RCIC turbine stop valve 9 normally closed.
Is fully opened and steam is sent from the RPV 1 to the RCIC turbine 8 to drive the RCIC turbine 8.

For this reason, the RCIC pump 7 and the RCIC bearing oil pump 10 directly connected to the RCIC turbine 8 are provided.
Is driven, and at the same time, the RCIC injection valve 11 opens. As a result, through the CSP side suction valve 12 which is being opened,
2 Condensate storage tank (hereinafter referred to as CSP) along the route indicated by the thick line
The cooling water of 13 is supplied to the RPV 1 (core injection).

As a result, the reactor water level rises and the water level rises (L-
8), the RCIC turbine stop valve 9 is fully closed and R
The CIC hand turbine drive steam is shut off, the RCIC pump 7 is stopped, and the injection of cooling water into the reactor is stopped. After that, when the reactor water level decreases again and the water level becomes low (L-2), the reactor is automatically restarted.

In this way, the initial water source of RCIC diameter is CSP
However, when the water level of the CSP 13 becomes low, the suppression pool 4 (hereinafter referred to as S / P) is automatically switched as shown in FIG. However, since the reactor 1 is actually scramming and some restoration work is being carried out, the stored water of the CSP 13 (hereinafter referred to as CS
It is unlikely that the water source will be used up and the water source will be switched to S / P4.

In FIG. 12, 4a is an S / P side suction valve,
Reference numerals 14 and 15 are first and second test control valves, 16 is a minimum flow bypass valve, 17 is an RCIC turbine stop valve, and 18 is R.
CIC main steam stop valve, 19 is RCIC control valve, 20 is R
CIC system flow transmitter, 21 is RCIC flow controller, 2
2 is an RCIC flow rate establishment detector, 23 is an RCIC discharge pressure transmitter, 24 is an RCIC discharge pressure establishment detector, and 25 is R
CIC discharge pressure gauge, 26 RCIC turbine speed pickup, 27 RCIC turbine speed indicator, 28
Is an RCIC bearing oil pump, and 29 is an EHC.

(2) Accident mode (see FIG. 13) In the event of loss of reactor coolant such as breakage of reactor piping, the reactor water level is low (L1.5) or the dry well pressure is high (eg 0.14 kg / cm ^2). ) Signal, the RCIC turbine 8 and the RCIC pump 7 are automatically started as in the reactor isolation mode of (1) above, and CSP water (see FIG. 12) is used as an initial water source and S / is used as a final water source. P (see FIG. 13) water is injected into the reactor through the water supply line 5. However,
When the low water level L-2 signal is generated before reaching the low water level (L1.5), the RCIC system is already activated. Further, the water source switching from the CSP 13 to the S / P 4 is automatically performed.

(3) System test mode (see FIG. 14) During normal plant operation, the RCIC turbine 8 and RCIC pump 7 are manually started using the reactor steam, and the S / P 4 to the RCIC pump 7 and the first test adjustment are performed. Circulation operation is performed using the test pipe A (indicated by the bold line in FIG. 14) that returns to S / P4 via the valve 14 and the second control valve 15 for system test, start test, and soundness confirmation of RCIC system. It is used for regular operation, which is carried out once a month for

In the conventional plant, CSP13 → R
There was a line for a system test of the IC pump 7 → CSP 13, and this line was used. However, RCIC pump 7
S / P4 → R because it is located in the immediate vicinity of / P4
The CIC pump 7 → S / P4 piping is shorter and more economical, and the ABWR has a new S / P water purification system, and S / P4 pool water (hereinafter referred to as S / P water) In order to maintain the cleanliness, even if the initial water source is S / P water, even if core injection is performed, impure dusts and the like are not brought into the reactor. Therefore, a design change was made in which the system test line of the CSP 13 was omitted.

Also, in CSP13 and S / P4, CSP1
No. 3 has a higher water level, so when the CSP 13 is the water source, the control valves 14, 15 for the first and second tests erroneously open and the CSP water flows into the S / P 4 due to the head difference.
Only when the water source is set to S / P4 so that the RCIC pump 7 and the RCIC turbine 8 directly connected thereto do not idle due to the flow of the CIC pump 7 → S / P4, the first and second test control valves 14, 15 Is operated to open the valve, and otherwise an interlock is incorporated to prevent the valve from being opened.

[0016]

RCIC system [0005] is, the reactor pressure is in the range of, for example, between ^{10.6kg / cm 2 ~82.8kg / cm 2} , and the rated flow, for example, 1.35 million kWe
In the case of class ABWR, it is designed to control and maintain 182 m ³ / hr. In order to confirm the adjustment of the control system, it is necessary to carry out a test for RCIC system control circuit adjustment at the start-up test. First, the test loop is adjusted, and finally the reactor water injection is performed. It is necessary to carry out, and to collect and adjust the test data at that time.

In order to realize it, first, adjustment in the system test mode is carried out, and then core injection is carried out. For that purpose, it was planned to carry out water purification of S / P4.

If the cooling water is suddenly injected into the reactor 1 without adjusting the control system, hunting may occur in the reactor injection flow rate. Therefore, the first reactor injection (core injection) is performed to some extent. It is necessary to switch to core injection after securing the flow rate and pressure by the test loop operation of S / P circulation.

Further, if the RCIC pump 7 is stopped at the time of core injection, disturbance will be given to the feedwater control system of the nuclear reactor. Therefore, the test loop operation should be slowly switched so as not to give disturbance to the feedwater control system. Need to stop.

However, even during the start-up test and during the commercial operation, the S / P water purification system is operated to purify the S / P water only immediately before the periodic inspection is started, and the S / P water is purified during the normal reactor operation. There are cases where P water is not purified.

By the way, the CSP 13 is a water tank for temporarily storing the condensate water of the generator driving turbine (not shown), and the CSP water is also used for the control rod drive system, the reactor recirculation pump and the reactor cleaning system (not shown) even in the normal time. It is used as the purge water for the pump, and the clean water is replenished for that amount, so the water quality is quite good.

On the other hand, S / P4 water is different from CSP water.
Normally, about 4000 t / hr of water is stored, and the stored water is used for other ECCS (emergency core cooling) not shown.
It is only used as a water source for the system's monthly regular test. Further, since the rust, dust and the like in the ECCS system piping are brought into the S / P 4 by the reflux water by the operation of the ECCS pump, the water quality is extremely bad if the purification is not performed.

For this reason, when the test loop operation is carried out using S / P4, which is to be used at the time of the first core injection in the start-up test, as the water source, poor quality water and rust, dust, etc. are brought into the reactor. In general, the water quality of a nuclear reactor is purified by various purification systems in order to reduce radiation exposure and prevent corrosion of fuel rods, internal structures, etc. in the reactor, and maintains extremely high purity. It is unacceptable to bring in S / P water containing a large amount of rust, dust, etc. Therefore, the test using the test loop up to now becomes impossible, and another test method is required.

Further, after the operation in the test loop during the start-up test and after the regular test during the operation, if the water source is switched to the CSP 13 and the direct injection into the furnace is carried out, the S / The relatively dirty water and dust of P4 remain, and there is a risk that they will be brought into the reactor during core injection.

However, in the case of an accident or the like, the probability of occurrence is extremely small, and since it is necessary to send cooling water into the furnace for a long period of several days, the final water source is switched to S / P4 and the inside of the furnace is switched. It is unavoidable to inject it into the furnace, but in the category of normal operation, it is desirable not to bring dirty water, impurities such as rust, and dust into the furnace from the viewpoint of reducing exposure.

Therefore, in order to prevent these from being brought into the furnace, it is necessary to clean the inside of the pipe by flushing the inside of the pipe, which was originally unnecessary in the design. However, since flushing of this pipe takes time, R
In the CIC start-up test, the test process is extended, extra labor is required during the commercial operation, and if possible, there is a demand for a method that eliminates the need for flushing.

Therefore, the present invention provides a method for operating a reactor isolation cooling system and an apparatus therefor capable of carrying out a start-up test without trouble even when the S / P water purification system is not in operation. With the goal.

Another object is to eliminate the need for flushing after the regular test in the RCIC system test mode.
The water held in the IC pipe is replaced with CSP water, and S is added at the time of core injection.
/ P An object of the present invention is to provide an operation method and apparatus that prevent water, dust, etc. from being brought into the furnace.

[0029]

According to the invention of claim 1, at the time of core injection, water from a condensate storage tank as a water source is used as a reactor pressure vessel.
Injection into the suppression pool during the start-up test
Water from the RCIC pump back to the suppression pool
In the operating method of the cooling system for reactor isolation during recirculation operation, the reactor partition using the suppression pool as a water source is used.
After completion of startup tests away cooling system, the RCIC pump
Operate the water in the above condensate storage tank to the suppression pool
To clean the piping and then use the condensate storage tank as a water source.
The water is injected into the reactor pressure vessel .

According to the first aspect of the present invention, at the time of injection into the RCIC start-up test reactor, the RCIC pump is started through a pipe path for draining clean CSP water to the S / P, and after establishing the system flow rate and pressure, the discharge is performed. By switching the line from the S / P side to the furnace injection side, the relatively unclean S / P water remaining in the S / P drainage pipe is pushed out by clean CSP water and drained to the S / P side. However, it is possible to switch to the core injection after replacing with clean CSP water. Therefore, the first core injection can be slowly switched without introducing relatively unclean S / P water into the reactor.

According to a second aspect of the present invention, in the method for operating the reactor isolation cooling system according to the first aspect, after the RCIC pump is activated, the stored water in the condensate storage tank is drained to the suppression pool midway. When opening a plurality of control valves interposed in series, after opening the control valve on the downstream side,
The upstream control valve is opened with an opening smaller than the opening of the downstream control valve, and the valve opening difference between these is set to 10% or less.

According to the present invention, after the RCIC pump is activated, the downstream control valve is opened, and then the upstream control valve is opened with a smaller opening than the downstream control valve. Since the valve opening difference is set to 10% or less, it is possible to prevent or reduce the occurrence of cavitation in the upstream side valve and improve the soundness.

The invention of claim 3 is characterized in that means for automatically operating the reactor isolation cooling system is provided by the method for operating the reactor isolation cooling system according to claim 1 or 2.

According to the third aspect, the operating method according to the first or second aspect can be automatically performed. Therefore, an erroneous operation due to a manual operation can be prevented in advance.

According to a fourth aspect of the present invention, the condensate storage tank is used as a water source at the time of core injection, and at the time of the test, in the start-up test of the operating method of the reactor isolation cooling system in which the RCIC pump is operated with the suppression pool as the water source, When the operation of the RCIC pump is stopped, it is characterized in that the discharge destination of the pump is switched from inside the reactor to the suppression pool.

According to the present invention, the stop of the RCIC pump after the RCIC core injection operation during the RCIC start test is performed.
By slowly switching the discharge side from the core injection using the CSP as the water source to the S / P side and stopping the flow, it is possible to prevent disturbance to the feedwater control system due to a rapid decrease in the RCIC system core injection flow rate.

The invention of claim 5 is characterized in that means for automatically operating the reactor isolation cooling system is provided by the method of operating the reactor isolation cooling system according to claim 4.

According to the fifth aspect, the operating method according to the third aspect can be automatically performed. Therefore, an erroneous operation due to a manual operation can be prevented in advance.

According to the sixth aspect of the invention, at the time of core injection, water from the condensate storage tank as the water source is injected into the reactor pressure vessel,
During the start-up test, the water in the suppression pool is circulated from the RCIC pump back to the suppression pool.
It is an operating device of the reactor isolation cooling system, in which the system flow of the reactor isolation cooling system is reduced to a predetermined flow rate that is less than the rated value, and the water held in this system piping is stored in the condensate storage tank. When the time required for replacement has elapsed, the suppression pool is provided with an interlock means for automatically closing the valve on the discharge side of the wastewater and thereafter stopping the operation of the RCIC pump.

According to the sixth aspect, the S / P drainage amount due to the replacement operation can be automatically suppressed to the necessary minimum by the interlock means.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. In addition, in FIGS.
The same or corresponding parts as those shown in FIGS. 12 to 14 are designated by the same reference numerals.

(First Embodiment) FIGS. 1 to 4 show steps of an RCIC operation method according to a first embodiment of the present invention, which corresponds to the first claim.

First, in the present embodiment, at the time of injecting cooling water into the core, relatively dirty water of S / P4, which is not cleaner than the stored water of CSP13, is not brought into RPV1, and after the system flow rate and pressure are established to some extent, In order to operate S / P4 as a drainage destination while using CSP13 as a water source,
It is necessary to open the CSP side suction valve 12.

However, when the CSP-side suction valve 12 is open, the first and second lines in the RCIC system S / P drain line are operated by the interlock operation that prevents the CSP water from flowing out to the S / P 4. The opening of the second test control valves 14 and 15 is prevented.

Therefore, first, the valve opening signal of the CSP side suction valve 12 is cleared by the isolation so that the first and second test control valves 14 and 15 which are the upstream and downstream control valves can be opened.

Next, when the first and second controlled flights 14 and 15 are opened before the RCIC pump 7 is started, the water in the CSP 13 is S / P4 due to the head difference between the CSP 13 and S / P4.
The RCIC pump 7 rotates due to the flow. For this purpose, the RCI directly connected to the RCIC pump 7
The C turbine 8 runs idle. RCIC turbine 8
When idling, the rotation speed of RCIC bearing pump 1
Since 0 is lower than the speed required to establish hydraulic pressure, the bearing will rotate without lubricating oil, and the RCI
The bearing of the C turbine 8 may be adversely affected. Therefore, the RCIC pump 7 is started before opening the first and second test control valves 14 and 15.

As shown in FIG. 1, when the RCIC pump 7 is started, the minimum flow rate bypass valve 16 is opened by the high discharge pressure signal and the low system flow rate signal to maintain the minimum flow rate for maintaining the soundness of the RCIC pump 7. Secure.

After that, in order to immediately secure the system flow rate, it is necessary to quickly open the first and second test control valves 14 and 15 for adjusting and opening, and the first and second test control. Valve 1
When the difference in opening between 4 and 15 is greatly opened, a load is applied to the valve 14 or 15 on one side, and the soundness of the valve 14 or 15 is impaired by cavitation. Therefore, as shown in FIG.
First, only the control valve 15 for the second test is opened slightly, and the RCIC is opened.
The pump 7 is started and immediately the first and second test control valves 1
The system flow rate is secured until the valves 4 and 15 are adjusted and opened and the minimum flow rate bypass valve 16 is closed.

When the system flow rate is established, the output of the RCIC flow controller 21 is manually increased to increase the rotation speed of the RCIC turbine 8.

Here, if the system flow rate is too high when switching from the test loop to the core injection, the disturbance to the feed water control system becomes large. Therefore, when the system flow rate is, for example, the rated flow rate is 182 m ³ / hr, Less than 10
When the temperature has risen to about 0 m ³ / hr, the RCIC flow controller 21 is automatically turned on at a flow rate of 100 m ³ / hr.

Since the system flow rate is automatically controlled at 100 m ³ / hr, the control valves 14 and 15 for the first and second tests are started from here.
Is adjusted to raise the discharge pressure of the RCIC pump 7 to a pressure at which the reactor can be injected. If the difference in opening between the first and second test control valves 14 and 15 opens, A load is applied to the valve 14 or 15 on one side, the soundness of the valve 14 or 15 is impaired by cavitation, and the tip of the second test control valve 15 is immediately discharged to the S / P 4, so that the back pressure is reduced. The opening difference is 10 because the cavitation easily occurs in the first test control valve 14.
% Or less, the opening degree of the first test control valve 14 is made small, and the second test control valve 15 is opened first while the first test control valve 14 is closed. It will be implemented first.

In order to carry out core injection with the RCIC pump 7, at least the discharge pressure thereof needs to be the reactor pressure + head difference. Therefore, the discharge pressure of the RCIC pump 7 is increased, and when the reactor pressure + head difference is reached, the RCIC injection valve 11 is fully opened for the first time as shown in FIG. 3, and the first and second test control valves 14 and 15 are opened. Close the valve gradually and slowly switch to core injection. Also at this time, the opening degree between the first and second control valves 14 and 15 is controlled in the same manner as described above. Finally,
As shown in FIG. 4, first and second test control valves 14, 15
Switching is completed when the valve is fully opened and R
Increase the flow rate of the CIC system.

By the method of this embodiment, the inside of the furnace (RPV
Stable injection of coolant into the reactor without bringing in relatively dirty water of S / P4 to 1) and without disturbing the water supply control system before adjusting the flow control system. can do.

(Second Embodiment) Next, a method of operating an RCIC which is a second embodiment corresponding to claim 4 of the present invention will be described with reference to FIGS.

First, if the discharge destination of the RCIC system injecting the coolant into the reactor is suddenly switched to S / P4 by the above procedure, a large disturbance will occur to the feedwater control system controlling the reactor water level. Therefore, for example, the system flow rate, for example, the rated flow rate is 18 when the RCIC flow rate controller 21 remains in the automatic mode.
In case of 2 m ³ / hr, it is lowered to about 100 m ³ / hr, which is smaller than this.

Here, in the core injection operation shown in FIG. 4, when the water source is still CSP 13 for the reason described above, the CSP suction valve 12 is open, so that the RCIC system S The first and second control valves 14, 15 of the / P drain line cannot be opened.
Therefore, the valve opening signal of the suction valve 12 is cleared by isolation so that the first and second test control valves 14 and 15 can be opened. When the core injection is performed according to the procedure of the first embodiment, it is already performed at that time, and it is not necessary to newly perform it here.

Next, the first and second test control valves 14 and 15 are gradually and slowly opened in a predetermined order, and the S / P from the core injection is started.
Although the drainage is switched to drainage, if the opening difference between the first and second test control valves 14 and 15 is large, the load is applied to the valve 14 or 15 on one side, and the cavitation causes the valve 14 or 15 to move. The loss of soundness and the second
Since the tip (downstream) of the test control valve 15 is immediately discharged to the S / P 4, back pressure is difficult to reach and the first test control valve 1
Since cavitation is likely to occur with respect to No. 4, the opening difference is set to 10% or less, and the opening of the first test control valve 14 is always made small as shown in FIG. The test control valve 14 will be implemented first.

After that, the first and second test control valves 14, 1
By gradually opening valve 5, the discharge destination is switched to S / P4, but when the discharge pressure of the RCIC pump 7 becomes less than the reactor pressure + water head difference, the core injection It is judged that it is no longer done, and Figure 2
The RCIC injection valve 11 is fully closed as shown in FIG. Finally R
If the first and second test control valves 14 and 15 are still open even after the operation of the IC pump 7 is stopped, the water of the CSP 13 is S / P.
4, the RCIC pump 7 idles due to the flow, and if the RCIC pump 7 is directly connected to this pump 7, the RCIC turbine 8 idles and the above-mentioned inconvenience occurs.

For this reason, before stopping the operation of the RCIC pump 7, the first and second test control valves 14 and 15 are fully closed, and as shown in FIG. The minimum flow bypass valve 16 is opened to maintain the soundness of the RCIC pump 7. RCIC pump 7 immediately afterwards
Perform the operation stop operation of.

By the method of the present embodiment, R during core injection
The CIC system can be stably switched to the test loop in the state before the adjustment of the flow rate control system is performed without giving any disturbance to the water supply control system, and the CSP 13 and the S after the RCIC pump 7 is stopped. / P4 head difference RCI
The idle rotation of the C turbine 8 can be prevented.

Next, the S / P at the time of the RCIC start test described above
Test method from start of drainage operation to switching to core injection, and switching from core injection to S / P drainage operation
The procedure manual which describes the procedure of the test method until the operation of the C pump 7 is stopped is shown.

In this procedure manual, the names and numbers of the respective equipments are the names at the ABWR 1.35 million kWe class plant.

By operating according to this procedure manual,
Even when a driving operator performs a special operation in an actual test, the driving operation can be surely performed with certainty.

Procedure for switching core injection during RCIC start-up test 1. Test Purpose / Outline 1.1 Test Purpose Confirm that the reactor isolation cooling system (RCIC) satisfies the specified performance.

1.2 Outline of Test A test is conducted to adjust the control elements of the RCIC system and confirm the performance.

[0066]

[Table 1]

[0067]

[Table 2]

[0068]

[Table 3]

[0069]

[Table 4]

[0070]

[Table 5]

[0071]

[Table 6]

[0072]

[Table 7]

[0073]

[Table 8]

(Third Embodiment) Next, an RCIC operation method according to a third embodiment of the invention will be described with reference to FIGS.

This embodiment is an example of an operation method for replacing the retained water remaining in the RCIC pipe with clean CSP water, and the stored water of CSP 13 is used as the water source of the replacement water. As shown in FIG. 5, the CSP side intake valve 12 is opened to switch the water source to the CSP 13.

Next, since the CSP 13 side is used as the water source, the first and second test control valves 14 and 15 cannot be opened due to the interlock, so the CSP side suction valve 12 open signal is cleared by isolation. .

After that, if the first and second test control valves 14 and 15 are opened before the RCIC pump 7 is started, the CSP is opened.
The stored water of 13 flows into S / P4 due to the head difference from S / P4. Because of this, the CSP water flow causes RCI
The C pump 7 and the RCIC turbine 8 directly connected to the C pump run idle. The oil around the bearing of the RCIC turbine 8 is supplied to the RCIC bearing oil pump 10 directly connected to the shaft.
RCI by the flow of RCIC system
When the C turbine 8 is idle, the RCIC bearing oil pump 10 does not establish a hydraulic pressure because of its low rotational speed, and the bearing rotates without lubricating oil of the bearing, which may adversely affect the bearing such as seizure. There is.

Therefore, the RCIC pump 7 is first activated and then the first and second test control valves 14 and 15 are opened. Even when the first and second test control valves 14 and 15 are fully closed, the minimum flow bypass valve 16 opens and R
Since the minimum flow rate for maintaining the soundness of the CIC pump 7 is secured, the first and second after the RCIC pump 7 is started.
The test control valves 14 and 15 may be opened. However, since the first and second test control valves 14 and 15 are opened immediately after that, it is desirable to slightly open the second test control valve 15 first as shown in FIG.

After the RCIC pump 7 is started, the openings of the first and second control valves 14 and 15 are gradually opened to secure the system flow rate, and as shown in FIG.
Conduct operation with P4 as the drainage destination.

Then, the water held in the system including the RCIC pipe is replaced with clean CSP water, and dust, rust, etc. adhering to the pipe are washed out to the S / P 4.

After the replacement, the operation of the RCIC pump 7 is stopped. Even at this time, if the RCIC pump 7 is stopped first, the head difference between the CSP 13 and the S / P 4 causes S to be S.
Since the water held in the CSP 13 flows into the / P4 side and the RCIC pump 7 and the RCIC turbine 8 run idle, the first and second test control valves 14 and 15 are fully closed first as shown in FIG. The RCIC pump 7 is immediately stopped during operation on the line passing through the flow rate bypass valve 16.

By carrying out this operation, the water held in the RCIC pipe can be replaced with the clean water of the CSP 13 in a shorter time than the conventional flushing.
Since the cleaning effect can be expected by the flow of clean water in the RCIC system, it is possible to suppress or prevent impurities from being brought into the reactor even when the RCIC system is injected into the core.

(Fourth Embodiment) Next, a driving method according to a fourth embodiment of the present invention will be described with reference to FIGS. 6 and 7.

In the third embodiment, CSP water is added to S / P4.
By draining the water to the RCIC pipe
The water replaced with P water and drained to S / P4 is finally treated once in the waste treatment system and then reused.

However, regarding the amount of water to be treated in the waste treatment system, it is preferable that the amount of water is smaller in order to reduce the treatment load.
High water level warning (for example, ABWR1
In the 350,000 kWe class, a low water level to a high water level of 45 m ³ / hr) occurs, so it becomes necessary to immediately send the raised water to the waste treatment system.

For this reason, a method for reducing the amount of wastewater discharged to the S / P 4 while performing the operation of replacing the retained water in the RCIC pipe is required.

Therefore, first, as shown in FIG.
After the pump 7 is started, in order to drain the S / P 4 from the operation of passing the minimum flow bypass valve 16, as shown in FIG. However, at this time, the above replacement effect can be fully expected if the flow rate is pushed for a few minutes at a certain flow rate, and therefore the RCIC system flow rate is surely closed by the minimum flow rate bypass valve 16 and a certain amount of flow occurs in the RCIC system. The expected flow rate is 80 to 9 which is about half of the rated flow rate (for example, ABWR 1.35 million kWe class plant, about 182 m ³ / hr).
Adjust to 0 m ³ / hr, run this for 5-10 minutes and RC
The operation of the IC pump 7 is stopped.

By this operation method, the inside of the RCIC pipe can be washed with clean CSP water, and the S /
The amount of drainage water to P4 can be reduced to 10 m ³ / hr or less, and the water level rise of S / P4 can be suppressed.

The following replacement operation procedure manual shows an actual operation procedure of the method for replacing the water held in the RCIC system pipe according to the third embodiment. In addition, in this procedure manual, the name and number of each device are described as the name of the ABWR 1.35 million kWe class plant.

By operating according to this procedure manual,
In the actual replacement operation, the driving operator can definitely carry out the driving operation without fail.

Replacement Operation Procedure This procedure is prepared with reference to the 1.35 million kWe class ABRW standard model and simulator.

1. Purpose / Outline 1.1 Purpose RCI after the surveillance test of RCIC system in preparation for core injection of RCIC
The retained water in the C system pipe is replaced with CSP water.

1.2 Overview The RCIC system is operated by the CSP water source / S / P discharge line,
Replace the retained water in the pipe with clean CSP water.

[0094]

[Table 9]

[0095]

[Table 10]

[0096]

[Table 11]

[0097]

[Table 12]

[0098]

[Table 13]

[0099]

[Table 14]

(Fifth Embodiment) FIG. 8 shows an interlock circuit for facilitating a replacement operation according to a fifth embodiment of the present invention.

In each of the above-described embodiments, the signal for opening the CSP side suction isolation valve 12 is cleared by the isolation in order to open the first and second test control valves 14, 15 when the CSP water source is used. However, it will be possible to automatically implement it with an interlock.

First, when the replacement operation mode is carried out, the replacement operation mode is selected by the mode selection switch 30. After this, when the RCIC pump 7 is started, the RCIC turbine speed signal 31 is received from the RCIC turbine speed pickup 26 by the RCIC pump operating condition judgment circuit 32, and when the turbine speed becomes a certain value or more, the pump is started from the judgment circuit 32. The signal 33 is output.

The AND circuit and wipes the opening prevention signal 35 of the first and second test control valves 14 and 15 by opening the CSP side suction valve 12 when the AND condition of the replacement operation mode selection signal 34 and the pump start signal 33 is satisfied. Out, RCI
First and second test control valves 14, 1 after the C pump 7 is started
The valve opening operation of 5 is possible.

As means for detecting the pump start at this time, in addition to the RCIC turbine speed, means for detecting the RCIC pump discharge pressure and detecting the pump start at a high pressure can be considered.

In FIG. 8, each or is an OR circuit, 36 is a blocking signal for the first and second test control valve open blocking signals, 37 is an RCIC automatic start signal, and 38 is a first test control valve operating switch. , 39 is a second test control valve operating switch, 40 is a first test control valve open command signal, 41 is a first test control valve close signal command, 42 is a second test control valve open command signal, 43
Is a control valve closing command signal for the second test.

(Sixth Embodiment) FIG. 9 is a flowchart of the automatic operation for facilitating the replacement operation according to the sixth embodiment of the present invention, and FIG. 10 shows an example of its logic circuit. Is shown. In addition, in FIG. 9, S1 to S15 indicate each step of the flowchart.

That is, when carrying out the replacement operation mode, first in S1, the replacement operation mode is selected by the mode SW (switch) 30. This allows RCIC in S2
System flow controller 21 is RCIC "manual" mode setting 0%
Switch to.

Thereafter, when the RCIC pump 7 is started in S3, the RCIC turbine 8 is operated at the minimum speed because the speed signal from the RCIC flow controller 21 is 0%. At this time, the RCIC turbine speed pickup 2
The RCIC turbine speed signal 31 from 6 is received by the RCIC pump operating condition determination circuit 32, and when the RCIC pump operating condition determination circuit 32 exceeds a certain value, a pump start signal 33 is output.

The AND of the replacement operation mode selection signal 34 and the pump start signal 33 wipes out the opening blocking signal 35 of the first and second test control valves 14 and 15 due to the opening of the CSP side suction valve 11, and the RCIC pump 7 is operated. It is possible to open the first and second test control valves 14 and 15 after the start of the valve, and at the same time, in S4, an open signal 44 is output to the first and second test control valves 14 and 15 to open the valve. do.

Next, the first and second test control valves 14, 15
When the RCIC system flow rate rises due to the opening of, the RCIC system flow rate establishment detector 22 receives the system flow rate signal 45 from the RCIC system flow rate transmitter 20 at this time, and when the flow rate exceeds a certain value, the flow rate is established in S5. When it is determined that it has been done, the system flow rate establishment signal 46 is output.

When the flow rate establishment signal 46 is received,
The condition of the second test control valve open signal 44 is not satisfied, and S
Simultaneously with the completion of the valve opening operation in 6, the flow rate setting is switched to a flow rate of about 50% of the rated flow rate in the control mode “automatic” of the RCIC flow rate controller 21 in S7, and the EHC 29 is signaled to reach the set flow rate. To control the RCIC turbine speed.

The system flow rate establishment signal 46 is also sent to the timed UP timer 47. In S8, when the fixed time (about 5 to 10 minutes) has elapsed with the time limit timer 47, it is determined that the replacement operation completion time has expired, and in S9, the first and second test control valves 1
A valve closing signal 49 is sent to 4 and 15 to close.

At S10, the first and second test control valves 14,1
If it is determined that SRC 5 is fully closed, a full-close command signal 50 for fully closing the RCIC turbine stop valve 9 is output in S11, and S1
When it is determined in 2 that the stop valve 9 is fully closed, S13
Then, the operation of the RCIC turbine 7 is stopped. Almost at the same time, in S14, the control mode of the flow rate controller 21 is "automatic".
The rated flow rate is set with and the replacement operation is completed in S15.

According to the present embodiment, it is possible to carry out all of the operations for replacing the water retained in the RCIC pipes automatically by the operator operating only the mode selection and pump startup. It is also possible to output the pump start signal by selecting the mode and carry out all the operations automatically. Furthermore, S /
The water level of P4 is monitored, and the pump 7
It is also possible to add an interlock for stopping.

Note that the logic diagram of FIG. 10 is an example for realizing the flowchart of FIG. 9, and how to assemble signals may be any logic circuit that realizes the flowchart of FIG. 9, and particularly the circuit configuration of FIG. Not be bound by.

(Seventh Embodiment) FIG. 11 is an operation diagram of an RCIC pipe replacement operation mode according to a seventh embodiment of the present invention.

In this embodiment, first, in order to prevent an erroneous operation in the replacement operation, the operation can be performed by the operator's mode selection. When the CSP 13 water source is used, the first and second test control valves 1 are provided.
Before opening the RCIC pump 7, the first and second tests are performed so that the CSP water flows out to the S / P 4 due to the accidental opening of 4, 15 and the RCIC pump 7 and the RCIC turbine 8 do not idle due to the flow. The feature is that an interlock is provided to prevent the control valves 14 and 15 from opening.

In addition, in order that the rated flow rate is not particularly required for the pipe cleaning operation and that the S / P water level rise is reduced,
The system flow rate during operation of the RCIC pump 7 is about half of the rated flow rate.

Further, regarding the operation time, the operation is performed for a time sufficient for the replacement operation, for example, about 5 to 10 minutes.

By technically defining the in-pipe replacement operation mode that defines these operation conditions, it can be used in normal operation without performing a special operation.

[0121]

As described above, according to the invention of claim 1 of the present application, a clean C is introduced at the time of injection into the reactor in the RCIC start-up test.
After starting the RCIC pump in the piping route that drains the SP water to the S / P and establishing the system flow rate and pressure, the discharge line is switched from the S / P side to the reactor injection side, resulting in a relatively unclean S / P The initial core injection can be slowly switched without bringing water into the reactor.

According to the second aspect of the present invention, after the RCIC pump is activated, the downstream side control valve is opened, and then the upstream side control valve is opened with a smaller opening than the downstream side control valve. Since the degree difference is set to 10% or less, it is possible to prevent or reduce the occurrence of cavitation in the upstream side control valve and improve the soundness.

According to the invention of claim 3, the operating method according to claim 1 or 2 can be automatically performed. Therefore, an erroneous operation due to a manual operation can be prevented in advance.

According to the fourth aspect of the present invention, when the RCIC pump is stopped after the RCIC core injection operation at the RCIC start test,
By slowly switching the discharge side from the core injection using SP as a water source to S / P and stopping it, it is possible to prevent disturbance to the feed water control system due to a rapid decrease in the RCIC system core injection flow rate.

According to the invention of claim 5, the operating method of claim 3 can be automatically performed. Therefore, an erroneous operation due to a manual operation can be prevented in advance.

According to the sixth aspect of the invention , the S / P drainage amount due to the replacement operation can be automatically suppressed to the necessary minimum by the interlock means.

[Brief description of drawings]

FIG. 1 is an RCIC according to first and second embodiments of the present invention.
FIG. 6 is an operation flow chart showing steps of the minimum flow rate bypass line operation at the time of starting the pump and before stopping the pump during the start-up test.

FIG. 2 is an RCIC according to first and second embodiments of the present invention.
FIG. 5 is an operation flow chart showing the steps of S / P drainage line operation during a startup test.

FIG. 3 is an RCIC according to first and second embodiments of the present invention.
FIG. 6 is an operation flow chart showing steps at the time of switching the reactor injection during the start-up test.

FIG. 4 is an RCIC according to first and second embodiments of the present invention.
FIG. 5 is an operation flow chart showing a core injection step during a start-up test.

FIG. 5 is an operation flow chart showing steps before pump startup during the replacement operation according to the third and fourth embodiments of the present invention.

FIG. 6 is an operation flow chart showing steps immediately after starting and immediately before stopping the RCIC pump during the replacement operation according to the third and fourth embodiments of the present invention.

FIG. 7 is an operation flow chart showing replacement operation steps during replacement operation according to the third and fourth embodiments of the present invention.

FIG. 8 is a logic circuit diagram of a fifth embodiment of the present invention.

FIG. 9 is a flow chart diagram of a replacement automatic driving device according to a sixth embodiment of the present invention.

FIG. 10 is a logic circuit diagram of a replacement automatic driving device according to a sixth embodiment of the present invention.

FIG. 11 is an operation flow chart of the replacement operation mode according to the seventh embodiment of the present invention.

FIG. 12 is an operation flow chart showing steps of using the CSP as a water source in the reactor isolation mode and the accident mode in the conventional RCIC operation method.

FIG. 13 is an operation flow chart showing steps of using S / P as a water source in the reactor isolation mode and the accident mode in the conventional RCIC operation method.

FIG. 14 is an operation flow chart in the system test mode in the conventional RCIC operation method.

[Explanation of symbols]

1 Reactor Pressure Vessel (RPV) 2 Reactor Containment Vessel (PCV) 3 Drywell (D / W) 4 Suppression Pool (S / P) 4a S / P Side Suction Valve 6 Main Steam Pipe 7 RCIC Pump 8 RCIC Turbine 9 RCIC turbine stop valve 10 RCIC bearing oil pump 11 RCIC injection valve 12 CSP side suction valve 13 condensate storage tank (CSP) 14 first test control valve 15 second test control valve 16 minimum flow bypass valve 18 RCIC main steam stop Valve 19 RCIC control valve 20 RCIC system flow rate transmitter 21 RCIC flow rate controller 22 RCIC flow rate establishment detector 23 RCIC discharge pressure transmitter 24 RCIC discharge pressure detector 25 RCIC discharge pressure gauge 26 RCIC turbine speed pickup 27 RCIC turbine speed Indicator 29 EHC 30 Operation mode selection switch 31 CIC turbine rotation speed signal 32 Operating condition determination circuit (detector other than RCIC rotation speed low) 33 Pump start signal 34 Mode SW replacement mode selection signal 35 Control valve opening prevention signal for first and second test depending on CSP side suction valve opening condition 36 Blocking signal of control valve opening blocking signal for first and second tests 37 RCIC automatic start signal 38 Control valve operating switch for first test 39 Control valve operating switch for second test 40 Control valve opening command signal for first test 41 Control valve closing command signal for first test 42 Control valve opening command signal for second test 43 Control valve closing command signal for second test 44 Control valve opening command signal for first and second test 45 System flow rate signal 46 System flow rate establishment Signal 47 Timed UP timer 48 Timed down timer 49 Control valve closing command signal for first and second tests 50 RCIC turbine stop valve fully closed command signal

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G21C 15/18 GDC

Claims (6)

(57) [Claims] 1. A condensate storage tank was used as a water source during core injection .
While injecting water into the reactor pressure vessel, the water in the suppression pool was resupplied from the RCIC pump during the start-up test.
In the operation method of the reactor isolation cooling system that performs circulation operation to return to the suppression pool,
After the start-up test of the reactor isolation cooling system that is the water source,
Run the RCIC pump to support the water in the condensate storage tank.
Discharge into the pressure pool to purify the piping, then
A method of operating a cooling system during reactor isolation , comprising injecting water from a condensate storage tank into a reactor pressure vessel . 2. The method for operating a reactor isolation cooling system according to claim 1, wherein after the RCIC pump is started, a condensate storage tank is connected in series in the middle of a drainage channel for draining the stored water into a suppression pool. When opening a plurality of control valves, after opening the downstream control valve, open the upstream control valve with an opening smaller than the opening of the downstream control valve, A method for operating a reactor isolation cooling system, characterized in that the valve opening difference is set to 10% or less. 3. An operating device for a reactor isolation cooling system, comprising means for automatically operating the reactor isolation cooling system according to the method for operating a reactor isolation cooling system according to claim 1 or 2. 4. The operation of the RCIC pump in the start-up test of the operating method of the RCIC cooling system in which the RCIC pump is operated while the condensate storage tank is used as the water source during core injection and the suppression pool is used as the water source during the test. The method of operating the reactor isolation cooling system is characterized by switching the discharge destination of the pump from inside the reactor to the suppression pool before shutting down. 5. An apparatus for operating a reactor isolation cooling system, comprising means for automatically operating the reactor isolation cooling system according to the method for operating a reactor isolation cooling system according to claim 4. 6. A condensate storage tank was used as a water source during core injection .
While injecting water into the reactor pressure vessel, the water of the suppression pool at startup test RCIC pump or al again substatement
An operation device for a reactor isolation cooling system that performs a circulating operation to return to the recession pool. When the time required to replace the stored water from the water storage tank has elapsed, the valve that discharges wastewater to the suppression pool is automatically closed, and then RCIC
An operating device for a reactor isolation cooling system, characterized by comprising an interlock means for stopping the operation of a pump.