JPS62138794A - Nuclear reactor feedwater-temperature controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a reactor feed water temperature control device for controlling the output of a nuclear power plant.

[Technical background of the invention and its problems]

Reactor feed water temperature side tII devices have been used for a long time, but conventional devices simply measure the thermal equilibrium heat balance between the reactor's thermal output and power generation output set in advance, for example, the void fraction in the core during rated power operation. It is controlled to be kept at about 40%.

Figure 7 shows the conventional equipment, and shows the reactor pressure vessel 1.
Steam generated in the turbine 1 is fed to the turbine 13 through the main steam pipe 12 and used to drive the turbine 13. The turbine 13 rotates the generator ff 1114 to generate electricity. In other words, thermal energy is converted into electrical energy. The steam supplied to drive the turbine 13 is led to a condenser 15 where it is condensed and sent as feed water to a feed water heater 17 through a condensate pipe 16. This feed water heater 17 heats the feed water using extracted steam extracted from the turbine 13 through an extraction pipe 18 .

Then, the feed water heated in the feed water heater 17 is returned to the reactor pressure vessel 11 through one water supply pipe, acts as a coolant in the reactor pressure vessel 11, and heats up the reactor core (not shown). The energy converts it into steam again.

Figure 8 shows the conventional device in more detail, and the feed water heaters are arranged in three parallel series A, B, and C.
A total of 15 feed water heating units, 5 of which are connected in series
17a△, 17aB, 17aC.

17bA, 17bB, 17bC, 17cΔ.

17c8, 17cC, 17dA, 17dB.

17dC, 17eA, 17eB, and 17eC are provided. And feed water heating 317a△, 1aaB.

17aC, oil and steam are respectively introduced from the high pressure turbine 13a. Similarly, water supply 11-burner heater 17bA, 1
7bB, 17bC have moisture 5) From the separator 20J3 and the first low pressure turbine 13b, the feed water heaters 17c△, 17c
B, 17cC is supplied from the first low pressure turbine 13b to the feed water heater 17 (jΔ.

17dB and 17dC from the first low pressure turbine 13b,
Extracted steam is introduced from the third low-pressure turbine 13d to the feed water heaters 17eA, 17eB, and '+7eC, respectively. Then, the feed water temperature is controlled by the temperature and amount of the extracted steam to be fed to the large number of feed water heaters 17aΔ to 17cC formed in this manner. For example, according to the preset heat balance consisting of the power generation output ratio-pickup water temperature ratio characteristic during rated output operation as shown in Fig. 9,
Feed water temperature (
The temperature is controlled to be approximately 200°C during rated output operation.

In this conventional device, when an operation other than the operation for maintaining the normal heat balance described above is performed, the feed water temperature is not actively controlled depending on the operation details.

On the other hand, if the water supply temperature is controlled during an operation other than the operation that maintains the normal heat balance, the following various effects will be produced.

For example, when the feed water temperature is lowered, the core inlet subcooling decreases, the void volume fraction in the core increases, the reactivity decreases, the reactor power decreases, and the power distribution peaks at the top, causing neutron Effects such as hardening of the flux spectrum and easier accumulation of plutonium are produced.

Conversely, lowering the feed water temperature increases core inlet subcooling, reduces in-core voids, and increases reactivity.
The reactor power increases, the power distribution peaks at the bottom, the neutron flux spectrum softens, and plutonium becomes easier to burn, among other effects.

These effects can be used to control output (startup, output change, load following operation, compensate for insufficient reactivity at the end of the cycle such as xenon reactivity compensation, control power distribution, improve neutron economy, reactor reaction This makes it possible to improve thermal stability and nuclear thermohydraulic stability.

However, in the conventional mounting, it is not possible to perform any operation other than the operation that maintains the normal heat balance, and therefore it is not possible to perform the operation that brings out the various effects described above.

〔Effect of the invention〕

The present invention has been made with these points in mind, and allows operation with the feed water temperature controlled even in cases other than the normal operation to maintain the reactor's heat balance, and allows the reactor output to be controlled in various operations. It is an object of the present invention to provide a reactor feed water humidity control device that can perform accurately controlled operation depending on the purpose.

(Summary of the Invention) The present invention relates to a reactor feed water temperature control system, which includes a feed water temperature control mechanism that adjusts the feed water temperature of a reactor water system, and an operation system that detects the operating state of the reactor and issues a detection signal. The state detection mechanism compares the operation request signal for the reactor with the detection signal.

and a controller that issues a feed water temperature adjustment signal to the feed water temperature adjustment mechanism to set the feed water humidity at node W4 so as to cause the feed water temperature adjustment mechanism to operate in accordance with the operation request signal.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 6.

FIG. 1 is a block diagram showing one embodiment of the present invention.

The same parts as the conventional one are given the same reference numerals.

In this embodiment, the operating state detection mechanisms for detecting the operating state of the nuclear reactor are a reactor system detection mechanism 21, a turbine/generator system detection mechanism 22, and a water supply system detection mechanism 2.
There are 3. This reactor system detection 1jiM +i42
1 detects the operating state of each component of the nuclear reactor system and sends a detection signal 21s. Specifically, core enthalpy, control rod insertion position, thermal output, power distribution, reactor pressure, core flow rate, minimum critical power ratio, maximum linear power density, etc. are detected by sensors (not shown), and their values are calculated. is output as a detection signal 21s. In addition, turbine/offfi system detection 618
422 detects the operating state of each component of the turbine/generator system and issues a detection signal 22s. Specifically, the photoelectric output, the main steam flow field, the main steam pressure, the amount of oil/vapor, the bleed steam temperature, etc. are detected by sensors (not shown), and the values thereof are output as the detection signal 22s. Further, the water supply system detection mechanism 23 detects the operating state of each component of the water supply system and issues a detection signal 23s. Specifically, the water supply flow rate, water supply temperature, water supply pressure, valve opening degree, drain height and drain water level of the feed water heater 17 are detected by sensors (not shown), and the values are output as the detection signal 23s. . In the vicinity of the feed water heater 17 and the like forming the water supply system, there is a feed water temperature fl! that adjusts the feed water temperature. An lff5 mechanism is provided. FIG. 2 shows an embodiment of this feed water temperature adjustment mechanism, and shows a bleed air pipe 18 that guides bleed steam to the feed water heater 17.
Several control valves 24 are provided in the middle to control the amount of bleed steam supplied as a heating source. In this embodiment, a controller 26 is provided to which the detection signals 21s, 22a, 23s are inputted from the detection mechanisms 21, 22.degree. 23, and an operation request signal 25s for the reactor is inputted. There is.

This operation request signal 25s is a signal requesting what kind of operation the nuclear reactor should perform, and is normally input by an operator. Then, the controller 26 compares the operation request signal 255 with each of the detection signals 215, 228° 23s, and operates the control valve 24 in accordance with the operation request signal 25s to provide feed water at a temperature that allows the reactor to operate. It is formed to issue a water supply temperature adjustment signal 26s to the control valve 24 to open and close it.

Next, the operation of this embodiment will be explained.

In this embodiment, the operating state of the nuclear reactor is constantly detected by a reactor system detection mechanism 21, a turbine/generator system detection mechanism 22, and a water supply system detection mechanism 23, and their detection signals 21S and 22s are transmitted.

23s is constantly compared with the operation request signal 25s by the controller 26, and the control valve 24 is continuously controlled to open and close using the feed water temperature adjustment signal 26s, so that the reactor can be operated while always satisfying the contents of the operation request signal 25s. can. Therefore, the feed water temperature can be easily controlled to be raised or lowered in accordance with the operation request signal 25s.

From this, in addition to the normal operation that maintains the -l- balance, it is possible to increase the temperature of the feed water and reverse the operation. As a result, the operating state of the reactor is such that the core inlet subcooling is reduced, the void fraction is at its upper limit, the core reactivity is reduced, the reactor power is reduced, and the power distribution is in an upward peak state, and the neutron flux spectrum is This results in the effect of hardening and accumulation of plu-1-nium.

Conversely, when operating with a lower feed water temperature, the core D-rib cooling increases, the void ratio decreases, the core reactivity increases, and the child reactor output increases, with the output distribution reaching a downward peak. This has the effect of softening the neutron flux spectrum and making plutonium more flammable.

Furthermore, by combining other reactor output control means such as control rod operation or core flow rate control 111 with the adjustment of the feed water temperature, the following output control can be achieved (1).

For example, when starting a nuclear reactor, changing output, negative? +? It is possible to control the reactor output during 1 follow-up operation, steady operation, etc. In addition, by lowering the feed water temperature at the end of 1 nicle, the positive reactivity of the void can be gained, and the reactivity at the end of 4 nucles can be increased. Furthermore, in the first half of the cycle, the feed water temperature is lowered to allow plutonium to accumulate, while in the early hours of the cycle, the feed water temperature is lowered to increase plutonium.
By avoiding the combustion of Ni, the reactivity can be improved and the neutron flux Svek1~Lucif1~ operation can be performed.

Furthermore, it is possible to adjust the power distribution to improve margin control of operation control values, core reactivity stability, nuclear thermal hydraulic stability of core tunnels, etc.

In Fig. 2, for ease of understanding, one control valve 24 is installed for one feed water heater 17, but the same applies to multiple feed water heaters. By applying this method, the temperature of the water supply can be freely controlled (the same applies to the embodiments shown in FIGS. 3 to 6 below).

In addition, when the control valve 24 is actually provided, it is possible to install the control valve 24 in all the air bleed pipes 18 connected to a large number of feed water heaters 17. In view of heat loss and pressure loss, the control valve 24 may be provided only in the bleed pipe 18 where it is necessary. for example,
Although it depends on the control width of the feed water temperature, the temperature control effect is particularly remarkable as shown in FIG. By providing the control valve 24 up to the bleed air piping 18, it is possible to freely control the temperature of the water supply, and to improve workability and economic efficiency when modifying or newly installing piping, valves, etc.

FIG. 3 shows an embodiment of the feed water temperature control mechanism.

In this embodiment, an on/off valve 27 is provided in the main flow part of the bleed pipe 18.
A control valve 24 is provided in a bypass pipe 28 of this on-off valve 27.

This is because when J3 is operated under high-temperature, high-pressure operating conditions such as in an atomic coupler, the control valve 24 suffers from pressure loss, heat loss, thermal reaction, fatigue, etc. due to its shape. Difficult to maintain. Therefore,
By forming the structure as in this embodiment, normal operation to maintain heat balance is possible by fully opening the on/off valve 27 of valve j and fully opening the other control valve 24, and performing operation at other feed water temperatures. can be operated with one on/off valve 27 fully open and the other control valve 24 fully open.

Thereby, by operating the control valve 24 by the necessary 0.1, the control valve 24 can be operated normally even under the high temperature and high pressure of the atomic coupler, and proper feed water temperature control can always be performed.

FIG. 4 shows the dimensions of yet another embodiment of the feed water temperature control mechanism. In contrast to the embodiments shown in FIGS. 2 and 3, which control the amount of oil and steam serving as a heating source, this embodiment controls the amount of water flowing into the feed water heater 17 for a constant amount of extracted steam. and configured to control the feed water temperature. rj, that is, the bypass pipe 29 is installed in the feed water heater 17.
The feed water flow rate control valve 30 on the upstream side and the bypass valve 31 of the bypass pipe 29 are opened and closed by the feed water temperature adjustment signal 26s from the tiller 26, and the feed water flow rate passing through the feed water heater 17 is controlled to generate heat. Adjust the exchange rate to adjust the water supply temperature. Thereby, the temperature of the water supply can be controlled even when there is no space to install the control valve 24 in the bleed pipe 18.

FIG. 5 shows another embodiment of a system for adjusting the temperature of the feed water, which is formed to control the flow of water into the feed water heater in the same way as FIG. 4. In this embodiment, the feed water heating 317 is connected in parallel.
A water supply flow rate control valve 30A is provided on the upstream side of each of aA, 17aB, and 17aC.

30B and 30C are provided, and these water supply flow rate control valves 30△
, 30B, 30G are controlled to open and close by the feed water temperature adjustment signal 26S from the controller 26, and each feed water heater 17aΔ,
17aB, 17aC, d'3 [heat exchange m] is adjusted to freely adjust the feed water temperature.

FIG. 6 shows a further embodiment of the feed water temperature regulating mechanism. In this embodiment, the water level of the drain 32 in the feed water heater 17 is variably adjusted to adjust the heat exchange area of the feed water heater 17 to adjust the feed water temperature. In other words, the water level of the drain 32 is detected by the drain water level gauge 33 installed in the feed water heater 17, and the detected water level is sent to the controller 26 as a detection signal 23s. The detection signal 23S and the operation request signal 25s are compared, and the water supply humidity adjustment signal 26S is determined.
is supplied to the oil valve 34 provided in the bleed air pipe 18 and the drain level control valve 36 provided in the drain pipe 35 of the feed water heater 17, and by controlling these valves 34 and 36 to open and close the drain 32. Adjust the water level and freely adjust the water supply temperature.

Note that the water supply temperature may be controlled by using a combination of these examples depending on the control purpose.

[Effect of excuse]

As described above, according to the reactor feed water temperature control device 711 of the present invention, it is possible to perform operation with the feed water temperature controlled even in cases other than the normal operation to maintain the P1 balance of the nuclear reactor. Effects such as being able to perform operations with accurately controlled furnace output according to various operating purposes are achieved.

[Brief explanation of drawings]

Fig. 1 shows a block diagram of an embodiment of the 6+1 reactor feed water temperature control system of the present invention, and Figs. 2 to 6 show horizontal embodiments of the reactor feed water temperature control system of the present invention. The block diagrams, FIGS. 7 and 8 are block diagrams showing the slave X device, respectively, and FIG. 9 is a J characteristic diagram showing the relationship between the power generation value J and the feed water temperature by the conventional device. 11... Nuclear reactor pressure vessel, 13... Turbine, 14
... Generator, 17... Feed water heater, 18... Air extraction piping, 21... Reactor system detection mechanism, 22... Turbine/generator system detection mechanism, 23... Water supply system detection Mechanism, 2
1s, 22s, 23s...detection signal, 24...control valve, 25s...operation request signal, 26...controller, 2
6s... Water supply temperature adjustment signal, 30... Water supply flow rate control valve, 34... Bleeding valve, 36... Drain level control valve. Applicant's agent Sato - Yu 2 Ki S Ki 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 96 Fig. 7 Prisoner

Claims (1)

[Scope of Claims] 1. A feedwater temperature adjustment mechanism that adjusts the temperature of water in the reactor water supply system, an operating state detection mechanism that detects the operating state of the reactor and issues a detection signal, and an operation request signal for the reactor. A reactor feed water temperature control device comprising: a controller that compares the detection signal with the detection signal and issues a feed water temperature adjustment signal to the feed water temperature adjustment mechanism to adjust the feed water humidity so as to perform an operation according to the operation request signal. 2. The operating state detection mechanism includes a reactor system detection mechanism that detects the operating state of the nuclear reactor system, a turbine/generator system detection mechanism that detects the operating state of the turbine and generator, and an operating state of the water supply system. 2. The reactor feed water temperature control device according to claim 1, further comprising a water supply system detection mechanism for detecting the temperature of the reactor feed water. 3. Reactor feed water temperature control according to claim 1, wherein the feed water temperature adjustment mechanism is configured to control the amount of bleed steam supplied as a heating source for the feed water heater. Device. 4. The reactor feed water temperature control device according to claim 1, wherein the feed water temperature adjustment mechanism is formed to control the flow of the feed water passing through the feed water heater. 5. The reactor feed water temperature control device according to claim 1, wherein the feed water temperature adjustment mechanism is formed to control the heat exchange area of the feed water heater.