JP3131512B2 - Nuclear power plant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atomic plant having a steam generator for roughly adjusting the output of a fast breeder reactor by moving a neutron reflector (hereinafter simply referred to as "reflector") installed around the core. More particularly, the present invention relates to a nuclear power plant for finely adjusting the output of a fast breeder reactor by adjusting the flow rate of water supplied to a steam generator.

[0002]

2. Description of the Related Art In general, a nuclear power plant is known which has a control rod control device having a complicated configuration in which the output of a nuclear reactor is controlled by control rods. Hereinafter, a nuclear power plant controlled by a conventional control device will be described with reference to FIG.

FIG. 10 shows a configuration of a conventional nuclear power plant 40 including a control device. First, the mechanism of power generation of the reactor will be described. The reactor 41 accommodates a core 42, and the core 42 generates heat by a fission chain reaction to heat a primary coolant flowing in the reactor. The heated primary coolant is sent to the intermediate heat exchanger 44 via the primary coolant high temperature side pipe 43, and the intermediate heat exchanger 44 transfers heat to the secondary coolant. The primary coolant, the temperature of which has dropped due to heat exchange, passes through the primary coolant low-temperature side pipe 45 again to the reactor 4.
Refluxed to 1. The circulation of the primary coolant is performed by a primary coolant circulation pump 46. The secondary coolant whose temperature has increased by heat exchange in the intermediate heat exchanger 44 is sent to a steam generator 48 as a load heat exchanger through a secondary coolant high-temperature side pipe 47, and the steam is generated by the steam generator 48. Heat the water supply to the generator. The secondary coolant whose temperature has dropped in the steam generator 48 is returned to the intermediate heat exchanger 44 through the secondary coolant low temperature side pipe 49. The circulation of the secondary coolant is performed by a secondary coolant circulation pump 50. The water whose temperature has increased by heat exchange in the steam generator 48 becomes steam, and drives the turbine 52 through the steam pipe 51 to generate power. Water supply to the steam generator 48 is performed by a water supply pump 53 via a water supply pipe 67, and the water supply flow rate Gw is adjusted by a water supply flow rate control valve 54.

Next, control of the output of the conventional nuclear power plant 40 will be described. The control device of the conventional nuclear power plant 40 includes an output setting device 55 for setting an output and a control rod 5.
6, a primary coolant flow control device 58 for controlling the flow rate of the primary coolant, a secondary coolant flow control device 59 for controlling the flow rate of the secondary coolant,
The feedwater flow rate control device 60 controls the feedwater flow rate Gw to the steam generator 48. The reactor power control device 57 uses the reactor exit temperature detected by the temperature detector 61 as a feedback signal based on the output setting signal from the power setter 55, and uses the neutron flux level detected by the neutron detector 62 as an auxiliary signal. The driving speed of the control rod 56 is calculated, and insertion and extraction of the control rod 56 are controlled based on the result. The output of the reactor 41 is adjusted by the extraction of the control rod 56. The primary coolant flow control device 58 uses the primary coolant flow rate detected by the primary coolant flow rate detector 63 as a feedback signal based on the output setting signal from the output setter 55 as a feedback signal to the primary coolant circulation pump 46. To control the number of revolutions. By changing the rotation speed of the primary coolant circulation pump 46, the flow rate of the primary coolant is adjusted. The secondary coolant flow control device 59 uses the flow rate of the secondary coolant detected by the secondary coolant flow rate detector 64 as a feedback signal based on the output setting signal from the output setter 55 as a feedback signal. To control the number of revolutions. By changing the rotation speed of the secondary coolant circulation pump 50, the flow rate of the secondary coolant is adjusted. The feedwater flow control device 60 includes an output setter 55
Based on the output setting signal from, the feed water flow rate detected by the feed water flow rate detector 65 is used as a feedback signal, and the steam temperature detected by the steam temperature detector 66 is used as an auxiliary signal to control the opening of the feed water flow rate control valve 54. The flow rate of water supplied to the steam generator 48 is adjusted by changing the opening of the flow rate control valve.

As described above, in the conventional nuclear power plant 40, the output setting device 55 controls the insertion degree of the control rod 56 so that
The flow rates of the secondary coolant and the secondary coolant and the flow rate of the water supply to the steam generator 48 are set. In order to maintain these set values, the output setter 55, the reactor power control device 57, and the primary coolant flow control device 58 Each of the secondary coolant flow control device 59 and the feedwater flow control device 60 operates, and the output target value of the reactor 41 is maintained.

[0006]

However, the above-mentioned conventional nuclear power plant control device includes an output setting device, a reactor power control device, a primary coolant flow control device, and a secondary coolant flow control device. And a feedwater flow control device, and its configuration is complicated. Further, since the reactor power control device directly operates the control rod, the control rod may be accidentally pulled out due to a failure of the reactor power control device itself. This problem is also the same when a reflector is erroneously operated in a nuclear power plant having a fast breeder reactor for roughly adjusting the output by driving the reflector. Accordingly, an object of the present invention is to solve the above-mentioned problems of the conventional nuclear power plant, to perform a rough adjustment of the power of the nuclear power plant by driving the reflector at a constant speed, and to adjust a flow rate of the water supply to the steam generator by adjusting the water supply flow rate to the steam generator. An object of the present invention is to provide a nuclear power plant having a simple structure capable of finely adjusting the output.

[0007]

In order to achieve the above object, a nuclear power plant of the present invention is driven at a constant speed,
A neutron reflector that roughly adjusts the heat output of the fast breeder reactor and a feed rate of the steam generator to breed the primary coolant at high speed by changing the combustion range of the core and maintaining the core combustion. A plant controller that changes the inlet temperature of the furnace and fine-tunes the heat output of the fast breeder reactor by a temperature feedback effect, wherein the plant controller has an outlet steam temperature of the steam generator, an outlet steam pressure, A heat output calculation unit that calculates the heat output of the steam generator with the flow rate as an input, and compares the set output value of the heat output of the steam generator with the heat output of the steam generator calculated by the heat output calculation unit. A heat output control unit that sets a feed water flow signal, detects a feed water flow of the steam generator, compares the feed water flow signal set by the heat output control unit, and sets a feed water flow control valve opening signal. And water supply And it is characterized in that comprising a flow rate control unit for controlling the amount.

[0008]

In the nuclear power plant according to the present invention, since the reflector of the fast breeder reactor is driven at a predetermined speed, the control rod or the control device for the reflector which was conventionally required can be simplified, and the reflector is rapidly breeded by the reflector. Rough adjustment of the output of the furnace can be performed, and it is possible to prevent the reflector from being erroneously operated due to a failure of the device that controls the reflector. Further, the nuclear power plant of the present invention calculates the actual output of the steam generator based on the steam temperature, the steam pressure, and the steam flow rate by the plant control device, and supplies the steam generator that generates the set output value of the nuclear plant. The difference from the flow rate is calculated, and the flow rate of water supply to the steam generator is controlled. The output of the fast breeder reactor is controlled by the temperature feedback effect by controlling the feedwater flow rate to the steam generator. That is,
If the actual output of the nuclear power plant is greater than the set output value, the feedwater flow to the steam generator is reduced, which causes the secondary coolant, the intermediate heat exchanger, the primary coolant The primary coolant temperature at the reactor inlet is increased,
As a result, the nuclear fission chain reaction of the core is reduced, and the power of the reactor is reduced. Conversely, when the actual output of the nuclear power plant is smaller than the set output value, the flow rate of the water supply to the steam generator is increased, whereby the secondary coolant, the intermediate heat exchanger, and the primary coolant are reduced. The primary coolant temperature at the reactor inlet is lowered through the reactor, thereby activating the fission chain reaction in the core and increasing the reactor power. This temperature feedback effect allows the plant controller to finely adjust the output of the fast breeder reactor.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a nuclear power plant according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a configuration of a nuclear power plant according to a first embodiment of the present invention. This nuclear power plant has a fast breeder reactor 2, and a reactor core 3 is accommodated inside the fast breeder reactor 2. Core 3
A reflector 4 that reflects the neutron flux emitted from the reactor core 3 and maintains the fission chain reaction of the reactor core 3 is provided around the core 3. The reflector 4 is configured to be driven upward by a reflector driving device 5. The reflector driving device 5 obtains driving power from the generator 6 of the nuclear power plant 1,
During operation of the plant, the reflector 4 is lifted upward at a predetermined speed, whereby the output of the nuclear power plant 1 is roughly adjusted. During operation, the inside of the fast breeder reactor 2 is filled with a primary coolant made of liquid sodium together with the reactor core 3, and this primary coolant is heated by the fission chain reaction of the reactor core 3, and the primary coolant high-temperature side pipe 7 is The heat is sent to the intermediate heat exchanger 8. In the intermediate heat exchanger 8, the primary coolant exchanges heat with the secondary coolant made of liquid sodium flowing through the intermediate heat exchanger 8, and heats the secondary coolant. The temperature of the primary coolant that has exchanged heat with the secondary coolant drops, and the primary coolant low-temperature side piping 9
Then, it is returned to the fast breeder reactor 2 again. The circulation of the primary coolant is performed by a primary coolant circulation pump 10. Next, the secondary coolant heated by the primary coolant in the intermediate heat exchanger 8 is sent to the steam generator 12, which is a load heat exchanger, through the secondary coolant high-temperature side pipe 11, and the steam generator The water supplied to 12 is heated. The secondary coolant, the temperature of which has dropped due to heat exchange in the steam generator 12, is returned to the intermediate heat exchanger 8 through the secondary coolant low-temperature side pipe 13.
The circulation of the secondary coolant is performed by a secondary coolant circulation pump 14. Next, the feedwater whose temperature has increased by heat exchange in the steam generator 12 becomes steam, and drives the turbine 16 through the steam pipe 15. The water supply to the steam generator 12 is performed by a water supply pump 17 via a water supply pipe 17a, and the flow rate of the water supply is performed by a water supply flow rate control valve 18.

A control apparatus and method for a nuclear power plant according to the present embodiment will be described below. The approximate output value of the nuclear power plant 1 of this embodiment is determined by the speed at which the reflector 4 is pulled up by the generator 6. Further, in the nuclear power plant 1 of the present embodiment, fine adjustment of the set output value is performed by the plant control device 19. The plant controller 19 controls the steam generator outlet steam temperature Ts detected by the temperature detector 20,
Steam generator outlet steam flow rate G detected by the flow rate detector 21
s, the steam generator outlet steam pressure Ps detected by the pressure detector 22, the feedwater flow rate Gw detected by the feedwater flow rate detector 23, and the set output value Wd set by the output setting unit 24, and
An adjustment value for the feedwater flow rate Gw is calculated, and a feedwater flow rate control valve opening signal is output to the feedwater flow rate control valve 18. By adjusting the feedwater flow rate Gw to the steam generator 12, fine adjustment of the output of the fast breeder reactor 2 is performed via the secondary coolant, the intermediate heat exchanger 8, and the primary coolant.

FIG. 2 shows the configuration of the plant control device 19. The plant control device 19 includes a heat output calculation unit 19a
And a heat output controller 19b and a flow controller 19c. The heat output calculator 19a receives the steam generator outlet steam temperature Ts, the steam generator steam pressure Ps, and the steam generator outlet steam flow rate Gs as inputs, and inputs the steam generator 1
2 is calculated. The heat output control unit 19b obtains a set output value Wd, which is a control target value of the heat output of the steam generator 12, from the output setter 24, and a heat output Ws of the steam generator from the heat output calculation unit 19a. Wd and heat output Ws
Of the water supply to the steam generator 12 is set by performing a linear operation on the deviation (Wd−Ws). The flow control unit 19c receives the feedwater flow rate Gw, performs a linear output operation on the deviation (Gd−Gw) from the feedwater flow signal Gd, sets the feedwater flow control valve opening signal Zd, and adjusts the feedwater flow rate. Output to the valve 18.

Next, the processing of each control section / calculation section of the plant control device 19 will be described below. FIG. 3 shows the flow of the process of the heat output calculation unit 19a. In step 101, the steam generator outlet steam temperature Ts, the steam generator outlet steam pressure Ps, and the steam generator outlet steam flow rate Gs are input to the heat output calculator 19a. Next, at step 102, the steam generator outlet steam enthalpy Hs is calculated from the steam generator outlet steam temperature Ts and the steam generator outlet steam pressure Ps. Next, at step 103, the enthalpy rise Hi in the steam generator 12 is calculated by subtracting a predetermined water enthalpy Hw at the time of the output operation. Next, in step 104, the heat output Ws of the steam generator 12 is calculated by the product of the enthalpy rise Hi and the steam generator outlet steam flow rate Gs.

FIG. 4 shows the flow of processing of the heat output control unit 19b. In step 201, the steam generator 12
The set output value Wd of the output setter 24 which becomes the control target value of
Then, the heat output Ws of the steam generator calculated by the heat output calculator 19a is input to the heat output controller 19b. Next, in step 202, a deviation (Wd-Ws) between the set output value Wd and the heat output Ws of the steam generator is obtained, and the deviation is subjected to a linear operation such as proportional, integral, or derivative to obtain a feedwater flow signal. Gd is set.

FIG. 5 shows the flow of processing of the flow control unit 19c. In step 301, the feedwater flow rate detector 2
3 and the heat output control unit 1
The feedwater flow signal Gd set by 9b is input to the flow control unit 19c. Next, at step 302, a deviation (Gd-Gw) between the feedwater flow rate Gw and the feedwater flow signal Gd is obtained, and the deviation is subjected to a linear operation such as proportionality, integration, differentiation, etc. Zd is determined. The feedwater flow control valve signal Zd is supplied to the feedwater flow control valve 18.
Is output to

The operation of this embodiment will be described below.
According to the above embodiment, the output of the fast breeder reactor 2 is roughly controlled by the rising speed of the reflector 4 which is directly driven by the output of the generator 6. Thus, it is possible to prevent an accident in which the reflector 4 is excessively pulled up due to a failure or malfunction of the control device that drives the reflector 4, and an excessive reaction is applied. In addition, a complicated drive device and control circuit for driving the reflector 4 are omitted, and the structure of the nuclear power plant is simplified.

According to this embodiment, the output of the fast breeder reactor 2 is finely adjusted by controlling the flow rate Gw of water supplied to the steam generator 12. The effect of the control of the feedwater flow rate Gw appears on the outlet side temperature of the steam generator 12 of the secondary coolant through the heat exchange of the steam generator 12, and further through the secondary coolant and the intermediate heat exchanger 8. Influences the temperature of the primary coolant on the inlet side of the fast breeder reactor 2. The temperature of the primary coolant on the inlet side of the fast breeder reactor 2 affects the nuclear chain reaction of the core 3 of the fast breeder reactor 2. As a result, the output of the fast breeder reactor 2 is automatically set to a value corresponding to the output of the steam generator 12. For example, the set value of the heat output of the steam generator 12 is
%, The feedwater flow rate Gw is controlled in an increasing direction, so that the temperature of the secondary coolant at the outlet of the steam generator 12 decreases, and the secondary coolant, the intermediate heat exchanger, and 1 The temperature of the primary coolant at the inlet of the fast breeder reactor 2 drops via the secondary coolant. As a result, a positive reactivity is applied to the reactor core 3 by the temperature feedback effect, and the fast breeder reactor 2
Of the steam generator 12 and settles to a value that is 10% higher than the value corresponding to the heat output of the steam generator 12. By controlling only the feedwater flow rate Gw without operating the control rod in this way, the output of the fast breeder reactor 2 can be set to a value corresponding to the set value of the heat output of the steam generator 12,
Should the plant control device 19 fail,
There is no possibility of accidentally pulling out the control rod and applying the reactivity to the reactor core, so that the reactor plant 1 can be operated safely and stably.

Another embodiment of the nuclear power plant according to the present invention will be described below with reference to FIG. In FIG. 6, the same parts as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.
The reflector 27 is accommodated in the outer periphery of the intermediate heat exchanger 2
8 are accommodated. The reflector 27 is configured to be driven upward at a predetermined speed by a driving device (not shown). The primary coolant is filled in the fast breeder reactor 25, and the primary coolant is driven by the primary coolant circulation pump 10 a and flows through the intermediate heat exchanger 28. A secondary coolant flows through the intermediate heat exchanger 28 so as to exchange heat with the primary coolant. The secondary coolant is driven by the secondary coolant circulation pump 14 and circulates between the intermediate heat exchanger 28 and the steam generator 12. The feed water whose temperature has been increased by heat exchange in the steam generator 12 becomes steam, and the steam pipe 15
To drive the turbine 16. In this embodiment, the rotation speed of the turbine 16 is controlled to a predetermined rotation speed by the main steam control valve 29, and the main steam pressure is controlled by the turbine bypass valve 30.
Is controlled to a predetermined pressure. The steam that has driven the turbine 16 and the bypassed steam are returned to water by the condenser 31, performed by the feedwater pump 17, and the feedwater flow rate Gw is adjusted by the feedwater flow rate control valve 18.

Next, the output control of the fast breeder reactor 25 during the start-up operation of the nuclear power plant according to the present embodiment will be described with reference to FIG. In step 401, the heat output Ws of the steam generator 12 is calculated by the heat output calculator 19a. Next, in step 402, the set output value Wd set by the heat output control unit 19b is input, and a deviation from the heat output Ws is obtained. At the time of startup, the set output value Wd input to the heat output control unit 19b increases at a constant rate of change, so that a deviation (wd−ws) always occurs between the set output value Wd and the heat output Ws calculated by the heat output calculation unit 19a. . Next, at step 403, a linear operation is performed on the deviation (Wd-Ws) to increase the heat output Ws of the steam generator 12 so that the feedwater flow signal G is increased.
d is set. Next, in step 404, the feedwater flow signal Gd and the feedwater flow Gw are input to the flow control unit 19c. In step 405, a deviation between the feedwater flow signal Gd and the feedwater flow Gw is obtained by the flow control unit 19c, and a linear operation such as proportional, integral, or derivative is performed on the difference (Gd-Gw), and the feedwater flow Gw is calculated. The feed water flow control valve opening signal Zd is set in the increasing direction. Next, at step 406, the set output value Wd of the controlled result
Is compared with the heat output Ws, and when it is determined that they are not equal (No), the above processing is repeated, and the set output value Wd
And the heat output Ws becomes equal. As described above, the steam generator 12 according to the rise of the set output value Wd
The effect of the increase in the feedwater flow rate Gw due to the feedwater flow rate control operation performed to increase the heat output Ws of the steam generator 12 is as follows.
Through the secondary coolant and through the intermediate heat exchanger through the secondary coolant and through the intermediate heat exchanger. When the temperature of the primary coolant decreases, the reaction of the reactor core 26 is activated and the output of the fast breeder reactor 25 increases, and such control operation continues until the set output value Wd becomes the rated set output value, Fast breeder reactor 2
5. Set the heat output of 5 to the rated output. Thereby, the output of the nuclear power plant can be safely and stably increased to the rated output state only by controlling the feedwater flow rate Gw without operating the control rod.

Next, the combustion compensation control of the nuclear power plant and the generator load following control of the nuclear power plant according to the present invention will be described with reference to the above embodiment. The reactor combustion compensation control will be described with reference to FIG. The coarse adjustment of the burn-up compensation of the core 26 is performed by the reflector 2
The output of the fast breeder reactor 25 is not completely kept constant due to the characteristics of the reflector 27, but the output slightly increases or decreases. In step 501, the heat output Ws of the steam generator 12 is calculated. Next, in step 502, if the heat output Ws changes, the set output value Wd and the heat output Ws of the steam generator are determined.
And a deviation (Wd-Ws) is generated between them. Then step 5
03, the deviation (Wd
−Ws) is obtained, and the feedwater flow signal Gd is set.
Next, in step 504, the flow control unit 19c converts the feed water flow signal Gd and the feed water flow Gw to the flow control unit 19c.
c. Next, at step 505, the feed water flow signal Gd and the feed water flow Gw are output by the flow control unit 19c.
(Gd−Gw) is obtained, the feedwater flow control valve opening signal Zd is set by linear calculation, and the feedwater flow control valve 18 is controlled. Next, in step 506, it is determined whether or not the set output value Wd as a result of the control matches the heat output Ws. If not, the above processing is repeated until the set output value Wd and the heat output Ws match. As described above, the thermal output Ws of the steam generator 12 can be controlled to a value corresponding to the set output value Wd only by operating the feedwater flow rate Gw for the combustion compensation of the nuclear reactor. Also in this case, the possibility of applying the reactivity of the reactor core 26 by accidentally pulling out the control rod is eliminated, and the operation of the nuclear power plant can be performed safely and stably.

Next, the generator load following control will be described with reference to FIG. When the load on the generator 6 is reduced, the main steam control valve 29 is closed, whereby the main steam pressure is increased, the turbine bypass valve 0 is opened, and excess steam is discharged from the condenser 3.
Bypassed to 1. In order to reduce the output of the fast breeder reactor 25 in accordance with the load of the generator 6, the output setter 24 gradually reduces the set output value wd. In step 601, the heat output W is calculated by the heat output calculation unit 19a.
s is calculated. Next, in step 602, a deviation (Wd-Ws) occurs between the reduced set output value Wd and the calculated heat output Ws. Next, in step 603, the deviation (Wd-Ws) is obtained by the heat output control unit 19b, and the feedwater flow signal Gd is set by linear calculation. Next, in step 604, the flow control unit 19c
The feed water flow rate Gw and the feed water flow signal Gd are read in accordance with the equation (1). In step 605, a deviation (Gd-Gw) between the feed water flow signal Gd and the feed water flow rate Gw is obtained, and the feed water flow control valve opening signal Zd is set by linear calculation. Then, the feedwater flow control valve 18 is controlled. Next, at step 606, it is determined whether or not the set output value Wd as a result of the control matches the thermal output Ws. If not, the above processing is repeated until the set output value Wd and the thermal output Ws do.

[0021]

As is apparent from the above description, in the nuclear power plant according to the present invention, the reactor power is roughly adjusted by driving the reflector at a constant speed, and the water supply to the steam generator is adjusted by the plant controller. The reactor power is fine-tuned by the temperature feedback effect, so the control rod control device required for a nuclear power plant that controls the power of the reactor by extracting the control rods can be simplified and the control rods can be operated incorrectly. As a result, it is possible to prevent an accident in which excessive reactivity is applied to the reactor. This makes it possible to obtain a nuclear power plant with a simple structure that can be safely and stably operated.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a processing flow of the plant control device of the present invention.

FIG. 3 is a block diagram showing a flow of processing of a heat output calculation unit.

FIG. 4 is a block diagram showing a processing flow of a heat output control unit.

FIG. 5 is a block diagram showing a flow of processing of a flow control unit.

FIG. 6 is a diagram showing a configuration of a nuclear power plant according to another embodiment of the present invention.

FIG. 7 is a block diagram showing a flow of control of startup operation of a nuclear power plant according to another embodiment of the present invention.

FIG. 8 is a block diagram showing a flow of a reactor combustion compensation control of a nuclear power plant according to another embodiment of the present invention.

FIG. 9 is a block diagram showing a flow of a generator load following control of a nuclear power plant according to another embodiment of the present invention.

FIG. 10 is a diagram showing a configuration of a conventional nuclear power plant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nuclear plant 2 Fast breeder reactor 3 Reactor core 4 Reflector 12 Steam generator 19 Plant control device 19a Heat output calculation unit 19b Heat output control unit 19c Flow control unit Ts Steam generator outlet steam temperature Gs Steam generator outlet steam flow rate Ps steam Generator outlet steam pressure Gw Feedwater flow rate Wd Set output value Zd Feedwater flow control valve opening signal Ws Steam generator heat output Gd Feedwater flow signal

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Makoto Ohno 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Toshiba Corporation Yokohama Office (56) References JP-A-4-64100 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G21D 3/00 G21C 7/28

Claims (1)

(57) [Claims] 1. A neutron reflector which is driven at a constant speed to maintain the combustion of the core by changing the combustion range of the core and to roughly adjust the heat output of the fast breeder reactor, and adjusts the feed water flow rate of the steam generator. And a plant control device that changes the inlet temperature of the fast breeder reactor of the primary coolant to finely adjust the heat output of the fast breeder reactor by a temperature feedback effect, wherein the plant control device includes a steam generator. Outlet steam temperature,
A heat output calculation unit for calculating the heat output of the steam generator with the input of the outlet steam pressure and the steam flow rate; and a set output value of the heat output of the steam generator and the steam generator calculated by the heat output calculation unit. A heat output control section for comparing the heat output with the heat output control section for setting a feed water flow rate signal; detecting a feed water flow rate of the steam generator; comparing the feed water flow rate signal set by the heat output control section with the heat output control section; A nuclear power plant, comprising: a flow control unit that controls an amount of water supplied by setting an opening signal.