KR100577474B1 - Integrated Reactor Low Flow Safety Grade Water Supply System - Google Patents

Abstract

The present invention provides a low flow safety grade water supply system that cools the reactor by supplying water stably without generating a residual residual heat removal system operation signal when a reactor trip signal occurs due to a cause other than a failure of the power conversion system in the integrated reactor water supply system. It is about.

The present invention provides a low flow rate water supply pipe branched from a branch point in front of the water supply control valve and connected to the nozzle front end of the main water supply pipe; A plurality of isolation valves provided in the low flow rate water supply pipe; An orifice provided on a downstream side of the isolation valve to adjust a water supply flow rate of the low flow rate water supply pipe; Multiple flowmeters provided downstream of the orifice; A check valve provided on the downstream side of the flow meter and provided upstream before joining the main water supply pipe; And a control unit for adjusting the flow resistance in the orifice by using the flow measurement signal of the main water supply pipe. It includes, and provides an integrated reactor low flow safety level water supply system for generating a reactor trip signal and the passive residual heat removal system operating signal using the water supply flow rate signal measured in the low flow rate water supply pipe.

Integrated reactor, main water supply system, passive residual heat removal system, low flow water supply system

Description

Integrated Reactor Low Flow Safety Grade Water Supply System {THE LOW FLOW RATE SAFETY-GRADE FEEDWATER SYSTEM FOR INTEGRAL REACTOR}             

1 schematically illustrates a conventional split reactor.

2 shows a cross section of a typical unitary reactor.

3 schematically illustrates a flow diagram of a conventional integrated reactor water supply system.

4 schematically shows a flowchart of an integrated reactor feedwater system according to the present invention.

* Description of the symbols for the main parts of the drawings *

100 ... Separation Reactor 200 ... Integral Reactor

110, 210 ... Containment (pressure) container 120, 220 ... Reactor (core)

130, 230 ... Pressurizer 140, 240 ... Steam generator

150, 250 ... coolant pump 160 ... steam turbine

170 ... Generator 300 ... Main Water Supply System

310 ... Main water supply pipe 320 ... Water supply pump

330 ... unsafe grade water flow meter 340 ... water supply valve

350 ... Water isolation valve 360 ... Check valve

370 steam nozzle 400 passive residual heat removal system

1 ... Low flow safety class water supply system 10 ... Low flow water supply piping

20 ... Isolation Valve 30 ... Orifice

40 ... flow meter 50 ... check valve

The present invention relates to a low flow safety level water supply system for an integrated reactor, and more particularly, to generate passive residual heat removal system when a reactor trip signal occurs due to a cause other than a failure of a power conversion system in an integrated reactor water supply system. The present invention relates to a water supply system for cooling a reactor by stably supplying water without generating an operation signal.

In general, nuclear power plants usually consist of more than 100 individual functions. These are largely divided into a nuclear steam supply system centered on a nuclear reactor, a turbine that receives steam, and runs a generator, a power plant, and other auxiliary equipment.

Here, in particular, the reactor is a device made to be used for various purposes such as generating heat by producing artificial control of the nuclear fission reaction of fissile material, the production of radioisotopes and plutonium, or the formation of radiation fields.

FIG. 1 illustrates a conventional loop type pressurized water reactor 100, which includes a reactor 120, a pressurizer 130, a steam generator 140, and a coolant pump 150 in a containment vessel 110. They are arranged separately and they are each connected via a pipe. The steam turbine 160 receives steam from the steam generator 140 to turn the generator 170 to produce electricity. Such a reactor improves the thermal efficiency of the entire process by increasing the temperature of steam generated by increasing the saturation temperature of water by increasing the pressure in the reactor.

2 illustrates a cross-section of an integral reactor formed integrally without pipes, unlike a separate reactor as described above.

As shown, the integral type reactor 200 includes a reactor 220 such as a pressurizer 230, a steam generator 240, and a coolant pump 250 constituting a nuclear steam supply system. ) Is installed without the pipe in the same pressure vessel 210 with.

The coolant heated in the nuclear reactor is supplied to the coolant pump 250, and then the coolant passes through the coolant pump 250 and the flow direction is changed downward to be supplied to the upper annular cavity of the steam generator 240. The coolant cooled by heat exchange while passing through the steam generator 240 is supplied to the reactor 220 again.

 The integrated reactor 200 as described above may basically exclude large coolant loss accidents of the existing separate reactor. That is, it has the advantage of excellent safety, miniaturization, and economic efficiency.

A conventional water supply system of the integrated reactor as described above will be described with reference to FIG. 3.

In the integrated reactor, the functions of the conventional water supply system are performed by the main water supply system 300 and the passive residual heat removal system 400.

As shown, the main water supply system 300 is connected to the steam nozzle 370 in the reactor pressure vessel 210 through the main water supply pipe 310 from the water supply pump 320. The main water supply pipe 310 has a water supply pump 320, a non-safety water supply flow rate meter 330 for generating an input signal of the water supply control system, a water supply control valve 340 installed in parallel, a water supply isolation valve 350, And a check valve 360. At this time, the water supply flow rate control is performed by one water supply control valve 341 and the other water supply control valve 342 stands by in an isolated state. In general, in an integral reactor, the water supply flow rate is maintained at 5 to 20% during start-up operation and between 20 to 100% during output operation.

In addition, the passive residual heat removal system 400 is an engineering safety system that operates when a reactor trip signal occurs due to a failure of a reactor power conversion system including a water supply flow rate, and passively condenses hot steam using natural convection. Safety equipment to cool the reactor. The operating residual value of the passive residual heat removal system due to the low water supply flow rate is lower than the minimum operating water supply flow rate of 5% and is determined in consideration of the error of the water supply flow meter.

When a reactor trip signal is generated due to a failure of a power conversion system including a water supply low flow rate, the reactor is tripped and the driven residual heat removal system 400 is operated to cool the reactor.

On the other hand, if a reactor trip signal occurs due to a cause other than a breakdown of the power conversion system, the feedwater flow rate should be approached to a new set point quickly. It is advantageous in economic terms.

Because the passive residual heat removal system is a driven system operated by the natural circulation principle by using the steam generator cassette in the reactor and the condensation heat exchanger located in the auxiliary building, once it starts to operate, the probability of failure in the state of not requiring driving power is increased. While it has the advantage of minimizing the cooling of the reactor, it is impossible to control the reactor cooling rate once it starts to operate and the restart procedure is complicated, which increases the time required to restart the reactor and consequently decreases the utilization of the reactor. .

However, such a conventional water supply system causes the residual residual heat removal system to operate at 5% or less in consideration of the error of the general water flow meter and the performance of the water supply control system when the reactor trip signal is generated by other causes except the failure of the power conversion system. There is a problem that it is difficult to obtain a set value of the driven residual heat removal system that does not operate.

In addition, even if the residual residual heat removal system operating signal set value due to the water supply flow rate is set to a small value, there is a problem that the passive residual heat removal system operating signal easily occurs. This is because the reactor trip signal is generated during operation at 100% water supply flow rate, and the water supply flow rate is rapidly reduced to 5%. This is because it stabilizes at%.

Therefore, there has been a need in the art for a low flow rate safety rating water supply system for an integral reactor that can avoid the above problems.

The present invention is to solve the above-described problems, the reactor trip signal is generated by a cause other than the failure of the power conversion system by further comprising a low flow rate safety grade water supply system at the rear end of the water supply pump in the integrated reactor water supply system In this case, it is an object of the present invention to provide a low-flow safety grade water supply system that cools the reactor by stably supplying water without generating a residual residual heat removal system operation signal.

In order to solve the above object, the present invention extends from a water supply pump to a nozzle through a main water supply pipe, and includes a main water supply system including a water supply control valve and a passive residual heat removal system operated by a reactor trip signal. A low flow rate water supply pipe branched from a branch point in front of the feed water control valve and connected to a nozzle front end of a main water supply pipe; A plurality of isolation valves provided in the low flow rate water supply pipe; An orifice provided on a downstream side of the isolation valve to adjust a water supply flow rate of the low flow rate water supply pipe; Multiple flowmeters provided downstream of the orifice; A check valve provided on the downstream side of the flow meter and provided upstream before joining the main water supply pipe; And a control unit for adjusting the flow resistance in the orifice by using the flow measurement signal of the main water supply pipe. It includes, and provides an integrated reactor low flow safety level water supply system for generating a reactor trip signal and the passive residual heat removal system operating signal using the water supply flow rate signal measured in the low flow rate water supply pipe.

Here, the multiple isolating valve is composed of a primary valve and a secondary valve, the secondary valve is preferably provided with two isolation valves in parallel.

At this time, it is preferable to isolate one of the secondary isolating valves installed in parallel on the low flow rate water supply pipe when the reactor trip signal is generated due to a cause other than a power system abnormality, thereby maintaining a constant water supply flow rate.

In addition, the control unit is preferably such that the flow rate ratio of the main water supply pipe and the low flow rate water supply pipe is 95: 5 during normal operation.

Preferably, the main water supply pipe flow rate supplied from the feed water pump does not fall below at least 5%.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 illustrates an integrated reactor low flow safety rating water supply system according to the present invention, which will be described below.

The water supply system according to the present invention comprises a main water supply system 300, a low flow rate safety grade water supply system 1, and passive residual heat removal system 400. The main water supply system 300 is a water supply pump 320, a non-safety water supply flow rate meter 330 for generating an input signal of the water supply control system, a water supply control valve 340, a water supply isolation valve 350, installed in parallel, And a check valve 360. This can be understood as a main water supply system for a general integrated reactor.

The passive residual heat removal system 400 is operated by a trip signal when the power conversion system abnormalities of the nuclear reactor, which can also be understood as using the passive residual heat removal system as a general integral reactor.

Technical features in the present invention is a low flow rate safety grade water supply system, which will be described in detail below.

The present invention may include a low flow safety level water supply system in an integrated reactor water supply system, wherein the low flow safety level water supply system 1 is a branch point of the front end of the water supply control valve 340, as shown in FIG. A low flow rate water supply pipe 10 branched from A) and connected to the front end of the nozzle 370 of the main water supply pipe 310 is provided.

The low flow rate water supply pipe 10 is provided with multiple isolation valves 20, wherein the multiple isolation valves 20 are formed of a first primary 21 and a secondary secondary valve 22, in which case The secondary valve 22 may be provided with two isolation valves 22a and 22b in parallel.

This is to maintain a constant water supply flow rate by isolating one of the secondary isolation valves 22a and 22b when the reactor trip signal is generated due to a cause other than a power system failure. That is, by isolating one isolating valve 22a and supplying only the other isolating valve 22b, a transient response characteristic can be improved in approaching the proper water supply flow rate of the low flow rate water supply pipe 10. have.

An orifice 30 is disposed downstream of the multiple isolation valve 20 to adjust the water supply flow rate of the low flow safety grade water supply pipe 10. At this time, when the secondary valve 22 is provided with two (22a, 22b) in parallel, the orifice 30 will also be provided on the downstream side (30a, 30b) respectively.

A plurality of flow meter 40 is provided on the downstream side of the orifice 30 and prevents a back flow to the front end of the steam nozzle 370 before joining with the main water supply pipe 310 downstream of the flow meter 40. A plurality of check valves 50 will be arranged.

The multiple flow meter 40 installed on the low flow rate safety grade water supply pipe measures the water flow rate on the low flow rate water supply pipe 10 to be used as a protection system input signal.

That is, when the water supply flow rate measured by the flow meter 40 decreases below the set value (5% of the total water supply flow rate), the reactor trip signal and the driven residual heat removal system 400 are generated.

In particular, in the present invention, since the measurement range of the flow meter 40 disposed in the low flow rate water supply pipe 10 is 0 to 10%, the non-safety installed in the main water supply pipe 310 having a measurement range of 0 to 100%. Compared with the grade water flow meter 330 has a relatively high accuracy can be obtained.

In addition, although the low flow rate safety grade water supply system 1 according to the present invention is not shown, a control unit (not shown) for controlling the flow resistance in the orifice 30 by using a flow measurement signal of the main water supply pipe 310. ) May be included.

The present invention, the low-flow safety grade water supply system (1) provided by the water supply flow rate to the main water supply pipe (310) through the low flow water supply pipe (10) not only during normal operation, but also in case of failure of the main water supply system, etc. It is possible to continue supplying% -10%. Therefore, this can prevent generation of the driven residual heat removal system operation signal at the reactor trip signal due to a cause other than a power system failure, and has the advantage of continuing to operate the reactor.

The operation of the integrated reactor low flow safety grade water supply system according to the present invention configured as described above will be described in more detail with reference to FIG. 4.

In the integrated reactor water supply system, the water supplied by the water supply pump 320 will be supplied to the main water supply system 300 and the low flow rate safety grade water supply system 1 while maintaining a flow rate ratio of 95.

This is to prevent the front trip of the reactor by maintaining a water supply flow rate of 5% to 10% with a low flow safety grade water supply system (1) even when a trip signal other than a power conversion system failure occurs. .

The water supply flow rate of the low flow rate water supply pipe is controlled by the flow resistance of the orifice 30 installed in the low flow rate safety grade water supply pipe 10 at the rear end of the branch point (A).

This means that when the non-safety grade water flow meter 330 installed on the main water supply pipe 310 is 100%, the measured value of the low flow rate water flow meter 50 installed on the low flow water supply pipe 10 is 5%. It will be determined by the controller (not shown) to be%.

As such, the controller (not shown) is an input signal for adjusting the opening degree of the water supply control valve 340 in order to stably maintain the total water supply flow rate obtained from the non-safety water supply flow rate measurement instrument 330 at a value set by an operator. It is preferable to use the entire flow rate signal measured by the feedwater flow meter 330 before the branch point (A). In addition, the input signal obtained from the water supply flow meter 330 is also used as a reference value for controlling the reactor output in the reactor output control system.

The water supply flow rate control of the output operation (water supply flow rate 20 to 100%) and the start operation (water supply flow rate 5 to 20%) is performed by one 341 of the water supply control valve 340, and the other one 342 is isolated. Stays in the state.

As described above, 5% of the total water supply flow rate is supplied to the low flow rate water supply pipe 10, which passes through the nozzles passing through all open multiple isolation valves 20 of the low flow safety level water supply system 1 during normal operation. 370 is joined to the front end side main water supply pipe (310).

However, if a reactor trip signal occurs due to a cause other than a failure of the power conversion system, the water supply control valve 341 opened on the main water supply system is completely isolated at a rate of 10% / second, and thus all water supply is It is supplied through the low flow safety grade water supply pipe (10).

When the water supply control valve 340 is completely isolated, the pressure at the front end of the branch point A is increased by the characteristic curve of the water supply pump 31, thereby increasing the water supply flow rate through the low flow rate safety grade water supply pipe 10. something to do.

At this time, it is preferable to isolate one 22a of the secondary valves 22a and 22b provided in parallel as described above. When the water supply isolation valve 22a is isolated, the flow resistance of the orifice 30b signaled from the controller (not shown) is determined so that the water supply flow rate through the low flow rate safety grade pipe 10 is 5%, and 5% water is supplied to the low flow water supply pipe.

In summary, when the water supply control valve 341 closes when the reactor trip signal is generated due to a cause other than a failure of the power conversion system, the water supply isolation valve 22a is isolated and the orifice signaled from the controller (not shown) The flow resistance of 30b) maintains the water supply flow rate at least 5% or more to the low flow rate safety grade pipe 10.

As such, when the reactor trip signal occurs due to a cause other than a failure of the power conversion system, the flow rate is always maintained at a value of 5% or more during a transient period by a low flow safety level water supply system. The problem of generation of the driven residual heat removal system 400 operation signal due to undershoot does not occur.

In addition, the present invention maintains a value of 5% to 10% of the flow rate during the transient period by the low flow safety grade water supply system even if the water supply control valve 341 causes a failure, so that a low water supply low flow signal is not generated. Continuous operation without reactor trip is possible. As a result, the output can be continued using the water supply control valve 342 in the standby state without stopping the reactor, thereby improving the utilization of the reactor.

The above has been described in detail with reference to the embodiments of the present invention, which is illustrative and does not limit the present invention.

The integrated reactor low flow safety grade water supply system according to the present invention can cool the reactor by stably supplying feed water without generating a residual residual heat removal system operation signal when the reactor trip signal is caused by a cause other than a failure of the power conversion system. In addition, there is an effect that can improve the utilization of the reactor.

In addition, the present invention has the effect of preventing the generation of the passive residual heat removal system operation signal caused by the under short during the transient period by providing a low flow rate safety grade water supply system.

In addition, according to the present invention, a relatively high accuracy can be obtained in generating a reactor trip signal and a passive residual heat removal system operation signal through a feedwater flow meter installed on a low flow safety grade feedwater pipe.

Claims (5)

In an integrated reactor water supply system, which includes a main water supply system including a water supply control valve and a passive residual heat removal system operated by a reactor trip signal, which is connected to the nozzle through a main water supply pipe. A low flow rate water supply pipe branched from a branch point in front of the water supply control valve and connected to a nozzle front end of the main water supply pipe; A plurality of isolation valves provided in the low flow rate water supply pipe; An orifice provided on a downstream side of the isolation valve to adjust a water supply flow rate of the low flow rate water supply pipe; Multiple flowmeters provided downstream of the orifice; A check valve provided on the downstream side of the flow meter and provided upstream before joining the main water supply pipe; And A control unit for adjusting the flow resistance in the orifice by using the flow measurement signal of the main water supply pipe; Including; An integrated reactor low flow safety level water supply system for generating a reactor trip signal and a passive residual heat removal system operation signal using the water supply flow signal measured in the low flow water supply pipe. The method of claim 1, The multiple isolation valve is composed of a primary valve and a secondary valve, the secondary valve is an integral reactor low flow safety level water supply system, characterized in that the two isolation valves provided in parallel. The method of claim 2, And one of the secondary isolation valves installed in parallel on the low flow rate water supply pipe to maintain a constant water supply flow rate when a reactor trip signal is generated. The method of claim 1, The control unit is a unitary reactor water supply system, characterized in that the flow rate ratio of the main water supply pipe and the low flow rate water supply pipe is 95: 5 during normal operation of the water supply system. The method of claim 1, Integral reactor water supply system characterized in that the main water supply pipe flow rate supplied from the water supply pump does not fall below 5%.

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