JPH08136693A - Reactor heating device - Google Patents

Abstract

PURPOSE: To heat reactor plant for startup by nuclear heating with a simple control. CONSTITUTION: In a power signal reference data memory 110, reference data indicating the relation of reactor power and coolant temperature for heating up a reactor in a target temperature rise rate are stored in advance. In a power signal target value calculator 108, the target value of the reactor power signal is calculated based on the present coolant temperature and the reference data. So as to attain this target value, control assembly is controlled with a control rod operator 114 to raise the temperature of the reactor. Besides, by treating the PUM indication value as a relative value to that of a certain time, the effect of arrangement of fuel rods and control rods on the reactor power can be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device for increasing the temperature of a nuclear reactor from normal temperature to operating temperature by utilizing nuclear heating, and more particularly to control of the heating device.

[0002]

2. Description of the Related Art When starting a nuclear reactor used in a nuclear power plant, light water as a coolant is cooled to room temperature (20
~ 50 ° C) to normal operating temperature (273-300 ° C)
It is necessary to raise the temperature. At this time, an upper limit is set for the rate of temperature rise of the coolant per unit time (temperature rise rate) for reasons of equipment. Equipment of nuclear reactors and other plants expands due to temperature rise, but if the speed of this expansion becomes too fast or there are variations depending on the location,
Thermal stress may cause equipment failure. Therefore, as described above, the upper limit of the temperature rise rate of the coolant is set to, for example, 55 ° C. per hour so that the thermal expansion of the facilities of the reactor and the plant is performed uniformly and relatively slowly. . In other words, the reactor and plant facilities are designed so that there is no problem even if the coolant temperature rises at 55 ° C./h.

As a method of increasing the temperature of the coolant of the nuclear reactor as described above, the output control material (control rod) for controlling the output of the nuclear reactor is gradually pulled out to increase the nuclear reaction, and the heat generated by the nuclear reaction is increased. Depending on the method, there is a method of increasing the temperature of the coolant. This heating method is generally called nuclear heating.

Conventionally, when the nuclear reactor is started by performing nuclear heating, the control rod is gradually pulled out by manual control to adjust the reactor output so that the temperature rise rate of the coolant reaches a predetermined target value. Was there. This target value has a margin so as not to exceed the upper limit value of 55 ° C./h of the above-mentioned increase rate, and is set to 30 ° C./h, for example.

[0005]

However, there is a time lag between when the reactor power is increased by controlling the withdrawal amount of the control rod and when the coolant temperature rises. When controlling the pull-out amount, there is a problem that an experienced operator who is fully aware of the above-mentioned time delay needs to perform the operation. Even if a skilled operator controls it, it is quite difficult to make the rate of increase of the coolant temperature equal to the target value. For example, if the operating state of the plant changes, such as when the circulation of coolant is started by using the generated steam in another system of the plant before the operating temperature is reached, the heat balance in the reactor immediately after this changes rapidly. Therefore, the rate of temperature rise of the coolant changes greatly. Even in the case of expert control,
I couldn't respond enough.

There is also a problem that the time required for activation becomes ten and a dozen hours, and if only a limited number of operators can operate during this time, the burden on this operator will increase. The present invention has been made in order to solve the above-described problems, and automates the reactor power control at the time of starting the reactor to reduce the burden on the operator and stabilize the rate of increase in the coolant temperature. An object of the present invention is to provide a reactor heating device capable of shortening the reactor startup time.

[0007]

In order to achieve the above-mentioned object, a heating device for a nuclear reactor according to the present invention is a reactor for heating from normal temperature to normal operating temperature by a nuclear reaction at the time of starting the reactor. A heating device, means for detecting the temperature of the reactor, means for detecting the output of the reactor, and a correspondence relationship between the reactor temperature and the reactor output when the temperature is raised at a predetermined temperature rise rate. Storage means for storing as standard data,
A means for calculating the reactor power corresponding to the current reactor temperature based on the standard data when heating the reactor, and controlling the advance / retreat of the core power control material based on the calculated reactor power And means.

Further, the standard data may be data showing a rate of change in reactor power for realizing a predetermined reactor temperature increase rate with respect to the detected reactor temperature.

Further, it may have means for detecting an operating state of a plant including the nuclear reactor, and the standard data may be data determined for each operating state of the plant.

Further, the means for detecting the output of the nuclear reactor may be a neutron detector for detecting the amount of neutrons in the nuclear reactor.

[0011]

The present invention has the configuration as described above, and the reactor power for realizing a predetermined rate of increase (target value) of the coolant temperature with respect to the coolant temperature detected at a certain point in time. The rise rate of the reactor is measured in advance to create standard data, and the reactor output rise rate corresponding to the current coolant temperature at the time of actual startup is controlled by adjusting the advancing / retreating amount of the control rod based on the standard data. Therefore, the rate of temperature rise of the coolant can be set to the target value.

Further, by storing the standard data for each operating state of the plant and controlling the output control material based on the standard data according to the operating state of the plant, the temperature of the coolant is changed even when the operating state of the plant changes. The rate of increase can be constant.

Further, the reactor output can be detected as the neutron amount in the core by using a neutron detector for detecting the neutron amount as the means for detecting the reactor output. Since the neutron amount follows the control of the output control material with almost no time delay, it does not require so much skill to control the advancing / retreating of the control material by observing the neutron amount. Therefore, the startup control of the nuclear reactor can be performed without depending on the expert.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic diagram of a nuclear power plant. A nuclear power plant is roughly divided into a nuclear reactor 10 that generates high-pressure steam and a power plant 12 that generates power using this high-pressure steam. Further, although omitted in the figure, various safety equipment and control equipment are arranged.

In the nuclear reactor 10, a reactor core 16 is arranged in a reactor containment vessel 14, and a fuel rod 18 containing a nuclear material which is a fuel in the reactor core 16 and a control rod for controlling a nuclear reaction of the fuel rod. 20 are arranged at a predetermined position at a predetermined ratio. The control rod 20 controls the nuclear reaction by advancing and retreating between the fuel rods 18, and the control rod control device 22 controls the advancing and retracting. The heat generated by the nuclear reaction of the fuel rods heats the coolant (light water) flowing in the pressure pipe 24, and the heated coolant is collected in the steam drum 26.

In the case of the nuclear reactor of this embodiment, two cooling systems are provided, and two steam drums 26 are also installed. The coolant stored in the steam drum 26 is guided to the outside of the reactor containment vessel 14 in the form of steam, and further passes through the main steam stop valve 28 and the steam control valve 30 to pass through the high pressure turbine 32.
Be led to. Further, the coolant discharged from the high-pressure turbine 32 is guided to the low-pressure turbine 36 in a dry state after the liquefied coolant is removed by the moisture separator 34. These high-pressure and low-pressure turbines 32 and 36 drive a generator 38 arranged coaxially with the high-pressure and low-pressure turbines 32 to generate electricity.

On the other hand, the coolant discharged from the low pressure turbine is liquefied in the condenser 40. As the cooling water (secondary cooling water) used at this time, seawater or the like pumped by the circulating water pump 42 is used as it is, and after taking heat from the coolant, it is returned to the sea or river again. The liquefied coolant is sent to the condensate demineralizer 46 and the feed water heater 48 by the condensate pump 44. Further, it is sent to the steam drum 26 by the water supply pump 50 via the flow rate adjusting valve 52. The liquefied coolant in the steam drum 26 is sent to the pressure pipe 24 by the recirculation pump 54, heated again, and sent to the steam drum 26. As described above, the amount of nuclear reaction in the reactor is controlled by adjusting the advancing / retreating amount of the control rod 20, and the output of the nuclear reactor is adjusted.

The above is the cycle during the power generation operation of the nuclear power plant according to the present embodiment. On the other hand, when starting this plant, the following operations are performed.

First, the main steam stop valve 28, the turbine bypass valve 56 and the flow rate adjusting valve 52 are closed so that the coolant circulates only in the reactor containment vessel 14. And
The control rod 20 is gradually pulled out to increase the amount of nuclear reaction. At this time, the coolant is circulated in the reactor containment vessel 14 by the recirculation pump 54, heated by the heat of the nuclear reaction, and the temperature gradually rises. Therefore, the temperature inside the steam drum 26 also rises, and steam starts to be generated. When the pressure in the steam drum 26 becomes equal to or higher than a predetermined value, the turbine bypass valve 56 opens, and most of the steam enters the condenser 40, is cooled by seawater, and returns to liquid. When the temperature of the cooling water reaches the rated temperature, the pressure of the steam drum 26 becomes the operating condition pressure. After that, power generation is started by the generator 38 after the output is increased until the reactor power becomes about 18%.

A more detailed view of the core is shown in FIG. As described above, in the nuclear reactor of the present embodiment, light water is used as the coolant, which flows through the inside of the pressure pipe 24 from the lower side to the upper side in the drawing, and the fuel rods 18 in the pressure pipe 24. It is heated by the heat generated by and is sent to the steam drum 26. The pressure pipe 24 is housed in a calandria pipe 60 provided in the calandria tank 58. The calandria tank 58 is filled with heavy water, which is a moderator, and in addition to the output control by the control rod described above, output adjustment is also performed by diffusing boric acid in this heavy water.
However, in nuclear heating at the time of reactor startup, output control is performed by the control rod.

FIG. 3 shows a plan view of the core.
The position of the fuel rod 18 is shown by a large circle,
The position indicated by the cross is the position of the control rod. Further, a local output detecting device 62 shown by a small circle, an output increasing detecting device 64 shown by a square, and a starting detecting device 66 shown by a triangle are arranged as shown in the figure.

When starting up in such a nuclear reactor, it is necessary to match the target value in order to keep the upper limit of the temperature rise rate of the coolant as described above. However, it is quite difficult to match the target value by manual operation.
Figure 4 shows the rate of change in coolant temperature when the reactor is started up to 1
A graph calculated every 0 minutes is shown. The temperature of the coolant is detected by the temperature sensor 68 provided inside the steam drum 26. As shown in the figure, the temperature change rate reaches the target of 30 ° C./h in about 2 hours, and even after reaching the target value, the target value goes in and out. It can be seen that, especially after slightly exceeding 5 hours, the temperature change rate greatly decreases and it takes about 1 hour 30 minutes to recover the temperature change rate. After that, as the temperature approached the operating temperature, the rate of temperature change was reduced, and a stable state was achieved. As described above, the main reason why the temperature cannot be stably increased at startup is that there is a time delay until the temperature of the coolant rises in response to the operation of the control rod 20 as described above. To be

Therefore, in this embodiment, the output raising detection device 64 responds to the operation of the control rod 20 without a time delay.
The detection output of (PUM) is the control target. PUM is a detector that detects the relative amount of neutrons in the reactor,
As shown in FIG. 3, in the case of the nuclear reactor of this embodiment, six pieces are arranged at predetermined positions. FIG. 5 shows how the indicated values of each of the six PUMs changed from the start-up time when the reactor was started up with the increase rate of the coolant temperature set to the target value of 30 ° C./h. An example is shown, but each P
The absolute value of the indicated value of UM shows a completely different value. However, at first glance, the PUM indication value that is disjointed is the value for the temperature of the coolant, and the indication value when the coolant temperature is 60 ° C is 1
When shown as a relative value when, the PUM output values substantially match as shown in FIG. That is, it can be seen that the manner of increasing the PUM indication value with respect to the temperature of the coolant is substantially uniform in the reactor 10. The fact that the rate of increase in the PUM indicated value is uniform in the reactor 10 means that the absolute value of the neutron flux in the reactor changes, but the relative distribution does not change much during nuclear heating. It is shown that.

The indicated value of PUM corresponds to the reactor power, and as described above, the relative distribution of neutron flux in the core has not changed much. Further, as described above, the PUM instruction value follows the control of the control rod with almost no time delay, and therefore, the control during nuclear heating based on this is easier than the control based on the coolant temperature. Output control can be performed.

FIG. 7 is a graph obtained by approximating FIG. 6 by a polygonal line. From this graph, it can be seen that there is a point where the slope of the graph greatly changes at a certain coolant temperature. Such a point is that the operating state has changed in the reactor and the plant including the reactor. For example, in the vicinity of about 180 ° C. in the figure, steam starts to be generated in the pressure pipe 24, the turbine bypass valve 56 is further opened, the steam enters the condenser 40, and is cooled by seawater to return to a liquid. In this way, even if the operating conditions of the entire plant change, the PU
The indicated value of M changes. For this reason, in this embodiment, in addition to the temperature sensor 68 for detecting the temperature inside the steam drum 26, in order to detect the operating state of the plant,
It has a pressure sensor 70 for detecting the internal pressure of the steam drum 26 and an air supply instruction detection unit (see FIG. 8) for detecting whether or not an instruction to send steam to the turbine has been issued.

From the above, the operating state of the plant is divided into several stages (S _{1 to} S ₄ in FIG. 7), and the rate of change of the PUM indication value is created as standard data for each stage. If the control rod is controlled so as to realize the PUM instruction value, the control operation can be easily performed.

The heating device for the nuclear reactor of this embodiment will be described in detail below. FIG. 8 is a block diagram showing the configuration of the heating device for a nuclear reactor of this embodiment. Reactor power detector 1
00 to detect the reactor power. Reactor power detector 1
00 uses a PUM that detects the neutron flux in the nuclear reactor. As described above, the absolute value itself of the output signal of the PUM is meaningless, and it becomes a numerical value that can be used only by taking a relative value with reference to a certain time point. In the case of this embodiment, at the time of starting the startup of the reactor,
For example, the PUM values at four points, that is, when the coolant temperature rises 10 ° C. from the start of startup, when the coolant temperature reaches 80 ° C., and when the instruction to open the turbine bypass valve 56 is given, are the reference values. As a result, the PUM indication value up to the next reference point is converted into a relative value. That is,
From the start of reactor startup until the temperature of the coolant rises by 10 ° C., the subsequent value is divided by the absolute value of the PUM output at the start of startup to calculate a relative value. And the coolant temperature is 10
When the relativization process start determination unit 102 determines that the temperature has risen by 0 ° C., the output signal relativity processing unit 104 causes the absolute value of the subsequent PUM indication value to be 10 ° C. higher than when the coolant temperature is started. The relative value is calculated by dividing by the value of.
Then, the output signal averaging processing unit 106 calculates an average value of the output signals of one or a plurality of PUMs which have been converted into relative values (hereinafter referred to as output signals). Similarly, even when the coolant temperature reaches 80 ° C., when the relativization process start determination unit 102 determines that the temperature is 80 ° C., the PUM instruction value (absolute value) at this time is used as a reference for subsequent PUM instruction value Absolute value)
Is converted into a relative value by the output signal relativization processing unit 104. Further, even when an instruction to open the turbine bypass valve 56 is given, the subsequent PUM instruction value (absolute value) is made into a relative value with reference to the PUM instruction value (absolute value) at this time.

Then, the control target value of the output signal is calculated by the output signal target value calculation unit 108 based on the stage determined from the data indicating the operating condition of the plant and the output signal standard data corresponding to the stage. The output signal standard data is stored in the output signal standard data storage unit 110,
The details will be described later. The data indicating the operating status of the plant collected by the plant data collection unit 112 includes a valve opening instruction detection unit 116 that detects that an instruction to open the turbine bypass valve 56 has been issued. Then, the control rod operating unit 114 operates the control rod so as to achieve the target value of the output signal.

Further, in the case of this embodiment, the coolant temperature is detected by the coolant temperature sensor 68, and this is fed back to control the control rod. That is, the coolant temperature increase rate calculation unit 118 calculates the coolant temperature increase rate from the passage of time of the value detected by the coolant temperature sensor 68, and it is determined whether or not this matches the target value (30 ° C.). . If the target value has not been reached, the output signal target value is made larger than the standard data, and conversely, if the temperature increase target value has not been reached, the output signal target value is made smaller than the standard data.

FIG. 7 shows standard data of this embodiment. In the case of the present embodiment, the control from the start to the end of the reactor is divided into four stages S ₁ to S ₄ to control each stage. The first stage S ₁ is from the start of reactor startup until the coolant temperature reaches 60 ° C.
At this time, as described above, the relative value of the subsequent PUM output is calculated based on the absolute value of the PUM output at the start of activation. FIG. 9 shows the relationship between the coolant temperature in the first stage S ₁ and the relative value of the PUM output. The relative value of subsequent PUM output values is shown with the PUM output value at the start of activation (52 ° C.) as a reference. A graph in which the change in the output value of the PUM detector is linearly approximated is shown by a thick solid line in the figure. The slope α _{1 of} this graph is 4 × 10
^{Since it is -1} (1 / ° C), to achieve 30 ° C / h, P
It can be seen that the UM output should be increased by 30 × α ₁ = 12 (1 / h). In practice, for example, PUM every 1 minute
So that the output signal rises by 0.5 × α ₁ (= 0.2),
The control operation of the control rod may be performed.

When it is determined that the coolant temperature has risen by 10 ° C. from the start-up, the second stage S ₂ is entered, and the relative value of the PUM output thereafter is calculated with reference to the absolute value of the PUM output at this time. To be done. This graph is shown in FIG. Here, the reason for changing the reference value of the relative value is that PUM
This is because when the absolute value of the output is small, the ratio of the error is large, and the relative value calculated based on this is also greatly affected by this error. That is, the reference value is changed at this point in order to eliminate the influence of the error with the point when the absolute value of the PUM output becomes large to some extent and the influence of the error becomes small. The slope α _{2 at} this time is 4.2 ×
10 ^-2 (1 / ° C), so the second stage S ₂
, The PUM output is 30 × α ₂ = 1.26 (1 /
It turns out that it is enough to raise in h).

When the coolant temperature reaches 80 ° C., the third
The stage S ₃ is moved to. And PUM at this time
Using the absolute value of the output as the reference value again, the relative value of the subsequent PUM output is calculated. The graph at this time is shown in FIG. The inclination α ₃ of the third stage is 1.4 × 10 ^-2 (1
/ ° C.), therefore, it can be seen that in the third stage S ₃ , the PUM output value should be increased by 30 × α ₃ = 0.42 (1 / h).

The determination of the shift from the third stage S ₃ to the fourth stage S ₄ depends on whether a signal for instructing to open the turbine bypass valve 56 has been output. That is, when the pressure in the steam drum becomes, for example, 15 atmospheres or more, and steam starts to be taken out of the reactor 10, the process proceeds to the fourth stage S ₄ . When steam is taken out of the nuclear reactor 10, the state in which all the increased output is used to raise the temperature inside the reactor is used for the operation of the power plant, so the output is further increased. Need to let. For this reason, as shown in FIG. 7, the increase rate of the PUM output (gradient of the graph) is larger than ever.
Similar to each of the above-described stages, the PUM output value (absolute value) at the time of transition to the fourth stage S ₄ , that is, at the time of the instruction to open the turbine bypass valve 56 is used as a reference value, and the subsequent PUM output value Calculate the relative value. The graph at this time is shown in FIG. Also in the fourth stage S ₄ , the control rod can be controlled in the same manner as described above. That is, the slope α _{4 of} the graph is 1.6
Since it is × 10 ^-2 (1 / ° C), the PUM output value is 30 ×
It can be seen that it is sufficient to raise at α ₄ = 0.48 (1 / h).

Further, in each of the above stages, the rate of increase of the coolant temperature can be easily changed. For example, when changing the temperature rise rate from 30 ° C./h to 15 ° C./h in the fourth stage, the PUM output value is 15 × α.
It suffices to raise it at ₄ = 0.24 (1 / h).

Further, when the rate of increase of the coolant temperature does not match the target value, the target value of the PUM output signal is corrected.
When it is determined that the rate of increase in the coolant temperature is below the target value, the target value of the PUM output signal calculated as described above is corrected by multiplying it by a predetermined scale factor, and the corrected target value is corrected to the PUM output signal. To control. This correction is performed in consideration of the delay time from the operation of the control rod to the rise of the coolant temperature. That is, in the case of the present embodiment, this delay time is about 5 minutes, so it is judged every 5 minutes whether the rate of increase is the target value. If there is no improvement in the temperature rise rate even after 5 minutes, the magnification is changed and the PUM output signal is controlled by this target value.

It is possible to replace the above-described judgment criteria when shifting to the next stage with other conditions.
For example, although the first stage S ₁ to the second stage S ₂ are set to have a temperature rise of 10 ° C. from the coolant temperature at the start-up, they may be set to a fixed predetermined temperature, for example, 60 ° C. When the coolant temperature at the start of startup does not change significantly
It can be simplified. In addition, when shifting from the third stage S ₃ to the fourth stage S ₄ , the steam flow rate or the feed water flow rate is detected to detect that the cooling water has begun to come in and out of the reactor 10, and the stage is shifted. It is also possible to judge

In addition, the stages can be further subdivided according to the operating conditions of the reactor plant that change the inclination of the PUM output value with respect to the coolant temperature change, such as changes in heavy water temperature and control rod position. .

13 and 14 show the control flow of this embodiment. When the nuclear heating operation of the nuclear reactor is started, the stage flag F representing the current operation stage is set to 0 as an initial setting (S100). Next, the coolant temperature is detected (S101). Then, until the coolant temperature rises by 10 ° C. from the start of activation (S102),
The aforementioned α ₁ is read as the standard data α (S10
3).

Next, it is determined whether the stage flag F is 0 (S104). If the stage flag F is 0,
If it is the first control cycle of the above-mentioned first stage S ₁ and the stage flag F is 1, 2 of the first stage S ₁
It is the control cycle after the first time. First control cycle (F = 0)
If so, the PUM output value P ₀ ′ (absolute value) at this time is read (S105), and this is set as the reference value of the first stage S ₁ (S106). And the stage flag F
Is added to 1 and updated (S107). Further, the standard data correction coefficient a is initialized (a = 1) (S108). The correction coefficient a is obtained by finely modifying the standard data α to set the coolant temperature increase rate to a predetermined value (3 in the case of the present embodiment).
It is a coefficient for correcting this when it deviates from 0 ° C / h). Then, the standard data α is multiplied by the correction coefficient a to update the standard data (S109). First stage S ₁
In the case of the first control cycle of, a =
Since it is set to 1, the standard data α is not corrected.
Also, as will be described later, the target value of the coolant temperature rise rate (30 ° C
Even if / h) is achieved, the correction coefficient a is not updated, so control is executed based on the previous standard data α.

If it is determined in step S104 that the stage flag F is not 0, that is, if it is the second or subsequent control cycle after the first stage S ₁ is reached, the reference value P ₀ ′ is Since it has already been set, the process directly moves to step S109.

Next, the control target value P ₂ of the PUM is calculated (S110). This is because in the 1,2 th transition in the first control cycle of the first stage S _1, calculates a control target value P ₂ of the current based on the control target value P ₂ of the previous. That is, the PUM output value is calculated such that the cooling water temperature changes by 30 × Δt ₁ (° C.) after the control cycle Δt ₁ (hour), and this is set as the target value P ₂ . That is, PU
To update the M target value P ₂ ,

## EQU1 ## It is calculated based on P ₂ = P ₂ + 30 × α × Δt ₁ (1) The current PUM output value P ₁
If does not match the target value P ₂ (S111), the control rod is operated (S112). Then, the PUM output value P ₁ ′ changed by the control rod operation is read (S11
3), which is the reference value P set in step S106
_The relative value P ₁ is calculated by dividing by ₀ ′ (S11
4). The above steps S112 to S114 are repeated until the relative value P ₁ substantially matches the target value P ₂ in step S111. As described above, the PUM output changes with almost no time delay as the control rod advances or retracts, so that control can be easily performed. That is, even an unskilled person can perform the operation, and the operation can be automatically performed.

In step S111, the PUM output value P ₁
Is substantially equal to the target value P ₂ , it is determined whether or not the delay time Δt ₂ in which the coolant temperature increases after the PUM output value changes (S115). As previously mentioned,
Since there is a delay time peculiar to the reactor in order to raise the temperature of the coolant after operating the control rod, it is evaluated whether or not the control rod operation was appropriate after the elapse of this delay time.
This evaluation will be described later. When the delay time Δt ₂ has not elapsed, it is further determined whether the control cycle Δt ₁ has elapsed (S116). When the control cycle Δt ₁ has elapsed, the process returns to step S101.

In step S115, if the control delay time Δt ₂ has elapsed since the reactor was started or the previous standard data was evaluated, the coolant temperature at this point T ₁ is read (S117). Then, it is determined whether the read coolant temperature T ₁ has risen from the coolant temperature T ₀ at the time of the previous evaluation at a rate of 30 ° C./h (S118, S119). Temperature rise rate is 30
Within the range of ± (ΔT / Δt ₂ ) ° C./h, the standard data α is not corrected at this time, the coolant temperature T ₁ at this time is newly set to T ₀ (S120), and then step S
Move to 116. If the temperature rise rate is higher than the target value, the correction coefficient a is multiplied by 1 / k to reduce the correction coefficient (S121). Here, k is a predetermined constant exceeding 1. If the temperature rise rate is lower than the target value, the correction coefficient a is multiplied by k to increase the correction coefficient (S12).
2). Then, in any case, the process proceeds to step S120 and further proceeds to step S116.

The first stage S ₁ has been mainly described above. The same applies to the control after the second stage S ₂ . The second stage S ₂ is a case where it is determined in step S102 that the coolant temperature has risen by 10 ° C. or more from the start of startup, and it is determined that the coolant temperature has not reached 80 ° C. (S123). If the coolant temperature has not reached yet 80 ° C. at step S123, the second stage S ₂ reads the standard data alpha ₂ (S124). When the stage flag F is 1 (S125), the process proceeds to step S105. Then, the PUM output value P ₀ ′ (absolute value) at this time is newly set as the reference value of the second stage (S106). If the stage flag F is not 1 in step S125, the setting of the reference value has already been completed, so the process proceeds to step S109. After that, the same operation as described above is performed in steps S110 to S122.

In the third stage S _{3, it} is determined that the coolant temperature has risen by 10 ° C. or more from the start of the operation in step S 102, the coolant temperature is 80 ° C. or more in step S 123, and the turbine bypass valve is not open. This is the case (S126). If it is determined in step S126 that the turbine bypass valve is not yet open, the third
Reading the standard data α ₃ of the stage S ₃ (S12
7). When the stage flag F is 2 (S12
8) Go to step S105. Then, the PUM output value P ₀ ′ (absolute value) at this time is newly set as the reference value of the third stage (S106). Step S
If the stage flag F is not 2 at 128, the setting of the reference value has already been completed, so the process proceeds to step S109. After that, the same operation as described above is performed in steps S110 to S122.

In the fourth stage S _{4, it} is determined that the coolant temperature has risen by 10 ° C. or more from the start of the operation in step S 102, the coolant temperature has risen to 80 ° C. or more in step S 123, and an instruction to open step S 126 has been given. Further, it is a case where the coolant temperature does not reach 283 ° C. (S12).
9). If the coolant temperature is not reached the 283 ° C. at step S129, reads out the standard data alpha ₄ of the fourth stage S ₄ (S130). When the stage flag F is 3 (S131), the process proceeds to step S105. Then, the PUM output value P ₀ ′ (absolute value) at this time is newly set as the reference value of the fourth stage (S
106). If the stage flag F is not 3 in step S131, the setting of the reference value has already been completed, so the process proceeds to step S109. After that, step S
From 110 to S122, the same operation as described above is performed.

Finally, when the cooling water temperature reaches 283 ° C. in step S129, it is determined at this point that the nuclear heating has ended. The nuclear heating end temperature is a design value of the corresponding nuclear reactor plant and is not limited to 283 ° C, and is set to the design value for each nuclear reactor plant.

Further, the apparatus of the present embodiment does not control the nuclear heating by estimating the nuclear reaction itself which changes due to the operation of the control rod. As described above, the characteristic (standard data) peculiar to the nuclear reactor is obtained in advance, and the control is performed based on this. Specifically, the PUM can be adjusted by adjusting the forward / backward movement of the control rod.
Nuclear heating is controlled by the simple control of matching the actual PUM output value with the output target value. Therefore, the amount of calculation for controlling nuclear heating is extremely simple as compared with the case of estimating the change in nuclear reaction, and automation of nuclear heating can be easily realized.

[0049]

As described above, according to the present invention, with respect to the coolant temperature detected at a certain time, the reactor power output for realizing a predetermined coolant temperature increase rate (target value) is obtained. The rise rate is measured in advance to create standard data, and the reactor output rise rate corresponding to the current coolant temperature is controlled by adjusting the advancing / retreating amount of the control rod based on the standard data during actual startup. The temperature control of the coolant becomes easy, and the rate of increase can be set to the target value.

Further, by storing the standard data for each operating state (stage) of the plant and controlling the output control material based on the standard data corresponding to the operating state of the plant, cooling is performed even when the operating state of the plant changes. The temperature rise rate of the material can be made constant.

By using a neutron detector for detecting the amount of neutrons as the means for detecting the reactor output, the reactor output can be detected as the neutron amount of the core. Since the neutron amount follows the control of the output control material with almost no time delay, it does not require so much skill to control the advancing / retreating of the control material by observing the neutron amount. Therefore, the startup control of the nuclear reactor can be performed without depending on the expert. Also, it is possible to achieve automatic start control.

[Brief description of drawings]

FIG. 1 is a diagram showing a main configuration of a nuclear reactor plant including a nuclear heating apparatus for a nuclear reactor which is a preferred embodiment of the present invention.

FIG. 2 is a detailed view of a core portion of the nuclear reactor of this embodiment.

FIG. 3 is a diagram showing an arrangement of fuel rods, control rods, an output detection device, and the like of the nuclear reactor of the present embodiment.

FIG. 4 is a diagram showing a time change of a temperature change rate of a coolant when warming up a reactor plant of the present embodiment to an operating temperature.

FIG. 5 is a diagram showing a time change of a PUM indication value (absolute value) according to the present embodiment.

FIG. 6 is a diagram showing a relationship between a relative value and a coolant temperature when the PUM output value in this example is 1 at 60 ° C.

FIG. 7 is a diagram in which the graph shown in FIG. 6 is linearly approximated.

FIG. 8 is a block diagram showing the configuration of a nuclear heating apparatus for a nuclear reactor of this embodiment.

9 is a diagram showing a relationship between a coolant temperature and a PUM output value in the first stage S ₁ shown in FIG.

10 is a diagram showing a relationship between a coolant temperature and a PUM output value in the second stage S ₂ shown in FIG.

11 is a diagram showing a relationship between a coolant temperature and a PUM output value in the third stage S ₃ shown in FIG.

12 is a diagram showing a relationship between a coolant temperature and a PUM output value in a fourth stage S ₄ shown in FIG.

FIG. 13 is a flowchart showing the control of this embodiment.

FIG. 14 is a flowchart showing the control of this embodiment.

[Explanation of symbols]

 10 reactor 12 power generation plant 14 reactor containment vessel 16 core 18 fuel rod 20 control rod 22 control rod control device 24 pressure pipe 26 steam drum 30 steam control valve 56 turbine bypass valve 68 temperature sensor 70 pressure sensor

Front page continuation (72) Inventor Masaki Saito 3 Myojin-cho, Tsuruga City, Fukui Prefecture Power Reactor / Nuclear Fuel Development Corp. Inside the New Converter Fugen Power Plant

Claims (4)

[Claims] 1. A nuclear reactor heating device for raising a temperature from room temperature to a normal operating temperature by a nuclear reaction at the time of starting the nuclear reactor, the means for detecting the temperature of the nuclear reactor, and the means for detecting the output of the nuclear reactor. And storage means for storing the correspondence between the reactor temperature and the reactor output as standard data when the temperature is raised at a predetermined temperature rise rate, and the current reactor temperature when the reactor is heated. And a means for calculating the reactor power corresponding to the above based on the standard data, and means for controlling the advance / retreat of the core power control material based on the calculated reactor power, . 2. The reactor heating apparatus according to claim 1, wherein the standard data is a change in reactor power for realizing a predetermined reactor temperature increase rate with respect to the detected reactor temperature. A heating device for a nuclear reactor, which is data showing a ratio. 3. The nuclear reactor heating apparatus according to claim 2, further comprising means for detecting an operating state of a plant including the nuclear reactor, wherein the standard data is determined for each operating state of the plant. It is a heating device for a nuclear reactor characterized by the above data. 4. The nuclear reactor heating apparatus according to claim 1, wherein the means for detecting the output of the nuclear reactor is a neutron detector for detecting the amount of neutrons in the nuclear reactor. A heating device for a nuclear reactor.