JPS59184886A - Method of controlling nuclear reactor power - 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] [Field of Application of the Invention] The present invention relates to a method of controlling the output of a nuclear reactor that involves changing the output, and is particularly suitable for changing the output of a nuclear reactor according to a predetermined output change pattern. This paper relates to an output control method.

[Prior art]

In conventional nuclear reactors, it is relatively difficult to change the output of the reactor due to changes in load due to restrictions on the core due to the insertion and withdrawal of control rods and restrictions on the output control system. It was a method of operation to replace the Raku output operation. However, as the number of nuclear reactors increases in recent years, there is a growing desire for a nuclear reactor m-force control method that can follow changes in load. In particular, the so-called day 9, when the counter-question output is lowered and the daytime output is increased to the rated value due to load fluctuations during the day and during the day. It is hoped that 13i=I will be developed as a method for controlling the output of a nuclear reactor that can perform ar-following switching.

Conventional daily load follow-up operation uses control rods, liquid poison, etc. to predict changes in core reactivity due to predetermined load changes, and to trickle changes in core reactivity based on the results of preliminary shutdown calculations. The 1i1J (Incorporated Foundation) method of inputting the control side reactivity is being considered. FIG. 1 shows an example of such a control method.

The daily load follow-up operation pattern shown in Figure 1 is to operate at the rated electrical output of 50% for 8 hours during the night, and to operate at the rated output for 14 hours during the day, resulting in a decrease in output and an increase in output. I try to do each one in one hour.

If the electrical output changes in the pattern shown in the upper part of FIG. 1, the change in the xenon concentration in the fuel rods produced by the nuclear reaction is determined as shown in the figure. Therefore, a change in reactivity due to a change in xenon concentration is determined, a change in reactivity due to a change in output is determined, and a total change in reactivity is determined by summing these reactivity changes. From this total reactivity change, the control required injection reactivity is determined and the liquid poison injection pattern is determined. However, predicting changes in core reactivity requires manual calculation of reactivity changes due to changes in reactor output, xenon reactivity, xenon absorption cross section, and other values that change with combustion, and it is difficult to predict correctly. The fire is on the 1st floor.

For this reason, for example, as shown by the broken line in Figure 1, when the predicted reactivity value based on the output coefficient is smaller than the actual reactivity value based on the output coefficient, the total predicted value of reactivity change is smaller than the total predicted value of reactivity change. As a result, the control injection reactivity actual value due to injection of liquid poison becomes a small value that is not sufficient to reduce the output to a predetermined value. For this reason, the output of the nuclear reactor cannot be lowered to a predetermined value because the output is less than the predetermined output that should be controlled. Therefore, in the past, the deviation between the predetermined output to be controlled and the actual output was controlled by frequently using a responsive reactivity control system, that is, a control rod as an auxiliary aid. However, the use of control rods
When the control rods are withdrawn to increase output, the temperature of the part where the control rods are inserted rises, causing a problematic noise that reduces fuel safety.

[Purpose of the invention]

The present invention has been made in order to eliminate the drawbacks of the prior art, and an object of the present invention is to provide a method of operating a nuclear reactor that can accurately follow the load.

[Summary of the invention]

The present invention calculates the actual core reactivity after the start of the power change, compares this core reactivity with the core reactivity predicted and calculated based on the power change pattern, and if there is a difference between the two core reactivity, By correcting the operating state quantity of the reactor at the start of the output change, which is the basis of the predictive calculation, and controlling the amount of poison in the moderator based on this corrected operating state quantity, the reactor output can be adjusted to the output change pattern. It is designed to enable accurate tracking.

[Embodiments of the invention]

Preferred embodiment 1 of the nuclear reactor output control method according to the present invention
j will be detailed according to the accompanying drawings. FIG. 2 is a system diagram of an embodiment of Yanghe in which the nuclear reactor output control method according to the present invention is applied to a heavy water-moderated nuclear reactor.

In Figure 2, the core 10 is for circulating heavy water, which is a moderator! A water circulation system 12 is connected to the heavy water circulation system 12, and a poison removal injection device 14 is installed in the heavy water circulation system 12. In addition, the reactor core 10 is controlled by +! r16 is inserted therein, and a neutron detector 18 for measuring the reactor core power is provided.

A poison concentration detector 20 is attached to the outlet of the heavy water circulation system 12 from the reactor core 10, and the detection signal of this poison concentration detector 20 is sent to the predictive calculation manual optimization device 22.
It is now possible to input. Further, the prediction calculation human power optimization device 22 receives a detection signal from the neutron detector 18 and also receives the insertion position of the control rod 16 via the control rod drive device 24 . The calculation results by the predictive calculation human power optimization device 22 are displayed on the calculation result display device 26.
At the same time, this calculation result is compared with the value determined by the take input from the data input terminal device 28.

The poison removal injection reference speed determination device 30 is electrically connected to the data input terminal device 28 and the prediction calculation input optimization device 22, and the determined poison removal injection speed gold reactor output control device 32 is connected to the data input terminal device 28 and the predictive calculation input optimization device 22. Poison removal injection device 14
Toriel. The reactor power control device 32 receives an output change pattern manually from the data terminal device 28 and controls the control rod drive device 624 in response to a detection signal from the middle 1st generation detector 18 .

Load following output control by the control system configured as described above is performed as follows.

For example, when performing daily load follow-up control, first input the electrical output change pattern for daily load follow-up into the data input terminal device 28, and also input data for predicting and calculating changes in core reactivity during daily load follow-up. input. This take includes the output coefficient, xenon reactivity, xenon cross-sectional area, etc., which are operating state quantities at the start of load tracking (for example, at rated output). The input data is then sent to the poison removal injection reference rate determining device 30 and used as the basis for predicting and calculating changes in core reactivity according to the output change pattern. The poison removal injection reference speed determination device 30 determines the poison removal injection reference speed for compensating for changes in reactor core reactivity according to the above input data, and reactor power control device 3
The calculation of 1 inputted to 2 in the poison removal injection reference speed determining device 30 is performed as shown in FIG.

The poison removal injection reference rate determining device 30 first predicts xenon concentration changes and samarium concentration changes based on the input output change pattern, output coefficient, xenon reactivity, xenon cross-sectional area, etc.

The change in xenon concentration and samarium 0°R degree can be determined by solving the following equation.

dX.

111φΣtYx+λ+I−(λX+φσsai)X,
-(2) ■ dP.

11φΣtYp−λpP□ ・−
・(3)t Here, ■ ;Iodine agglomeration degree (number density) in fuel X,;
〃 Xenon concentration P,; // Promethium concentration Sm; // Samarium concentration φ; 〃 Average neutron flux Σ,; 〃 Macro fission cross section Y; Production rate by nuclear fission of each atom λ; Area t: Using the time change in the xenon concentration and samarium concentration determined over time, the time change in the reactivity between xenon and samarium is determined by the following equation.

Here, 4 on Δ? ', ΔKs m"; Reactivity X at rated output of L g S: atHS2"; X @, Concentration X at Sra's rated output, (t) ;
;//Samarium concentration Next, from the planned pattern of changing the reactor output manually, the change in reactivity due to the output coefficient from the rated output corresponding to the reactor output at each time is determined.

The reactivity change due to the output coefficient is as follows, assuming that the output at time tI + t2 is P (tl >, P (t2)), respectively.
It can be calculated using the following formula.

ΔKp′biL2−ΔKpH2′)−ΔKp(tt)
-f(P(h)J2'UP(tl))...(7)
f (P)=a-P+b-P2/2+CP3/3
・(8) Here, f(P) i Reactivity P by output coefficient ; heat output book) a, b, c ; Reactivity setting coefficient by output coefficient Furthermore, time t! The change in core reactivity from t2 to t2, 16r* (tr~t2) is calculated using the following formula to Δ.
r@(h~tz)=(ΔKX=t1″t2+ΔKgm
"-'+ΔKPt1-t2)...(9)
Here, ΔKcor-e; core reactivity change ΔKxa
; xenon reactivity change ΔK [1m; samarium reactivity change As described above, core reactivity change ΔK. . After determining ra (tI'□ t2), a poison removal injection reference speed is determined so as to compensate for changes in core reactivity within a predetermined time interval input from the data human terminal device 28. This poison removal injection reference speed V can be determined by the following equation.

VB(t,~t6)--ΔKa r. (1,~t
, )/ (t , -t , )-(10) In particular, t,
; Time segment start time t; ; End time The poison removal injection reference speed determined in this way is transmitted to the reactor power control device 32, and the poison removal injection command from the reactor power control device 32 is executed as the poison removal injection. It is transmitted to the device 14 and daily load tracking is started.

On the other hand, the output of the reactor core 10 is detected by the neutron detector 18 and input to the reactor power control device 32 . The reactor power control device 32 compares the output for a predetermined time based on the output change pattern manually entered from the data human power terminal device 28 and the reactor core power from the neutron detector 18 . and,
The reactor output 11↑control device 32 determines whether the reactor core output deviates by more than a predetermined value from the output change pattern. !
rll li'lil￥8; Give an output fine adjustment signal to the 4-wheel drive unit 24, and drive the control rod 16 to 1 via the control rod drive device 24.
The reactor is driven to return to the predetermined output given by the core output change pattern.

The positions of the poison particles injected into the heavy water as described above and placed in the reactor core are respectively sent to the predictive calculation input optimization device 22 and compared with predicted values. That is,
The amount of poison in heavy water is detected by the poison concentration detector 20 and transmitted to the n1 prediction calculation input optimization device 22.
The so-called poison JII:J injection reactivity injected into the reactor core is calculated in advance by the law calculation input optimization device 22. In addition, control (based on the signal from the total drive unit 24, the predictive calculation human power optimization device 22 calculates the so-called control injection reactivity of the control rods.In this way, the control rods are actually inserted into the core after the daily load tracking starts. The time change of the control side reactivity consisting of the poison control input reactivity and the control input reactivity is calculated and compared with the predicted value based on the data input from the data human power terminal device 28. This figure shows the flow of this comparison calculation in the predictive calculation input optimization device ii22.

Predictive calculation input optimization device 22 (d), based on the daily load follow-up output change pattern manually input from the data terminal device 28 according to the above-mentioned equations (1) to (9), and the xenon dynamic characteristic calculation data. Preliminarily calculate the change between 97ζ degree and samarium tack degree, and calculate the change in xenon reactivity,
Calculate and store the change in samarium reactivity. This storage device can be implemented by a magnetic storage device or storage element used in ordinary computers. After that, the reactivity change due to the power coefficient, and the core reactivity change ΔK e 6 F which is the sum of each of these reactivity changes. Calculate the prediction. On the other hand, the predictive calculation input optimization device 22 receives the poison concentration signal in heavy water from the poison concentration detector 20, the control rod position signal from the control rod drive device 24, etc., and calculates the actual value after the start of daily load tracking. The change in control side reactivity of the input to the reactor core over time is calculated using the following formula.

ΔKc/-R(t1-t2)-α(Ht2-Hll)・
...(11)ΔKB10(t+ ”□tz )−β(B
,'-Bt)...(12)2■ ΔKCONT (t)-ΔI(C/R(t)+ΔKB
"I t )=-(13) Here, ΔI(C/R(t
t~t2); Time 1. Control reactivity α input by the control rod from t2 to t2; input reactivity Hlt when the total output adjustment rod unit length is driven; average axial position ΔKn10 (t1 to t2) of the total output adjustment rod at time t1; time Control reactivity β injected with poison in heavy water from t1 to t2; Reactivity Btu injected per unit change in poison concentration Btu; Concentration of poison in heavy water ΔKCONT at time 11; Total control reactivity actually injected; However, The total control reactivity obtained in this way (in vain,
The target output based on the output change pattern does not necessarily match the control response of the suspension. Therefore, the control input reactivity performance correction 1 Δ for correcting the f''aj18 input reactivity so that the output becomes the target output is calculated by using the following equation.

∆' C0NT (t) - ∆Kcour (t) - c
f (P(t))−f(p(t) l ]=−(14
) Here, Δ is 'C0NT; Control input reactivity performance correction at time t-1 1st plane ΔKCON; Control input reactivity performance f(P(t)); Reaction by output coefficient at target output P degree f(I)(t)l; reactivity according to the output coefficient at actual output p; The reactor core output at actual time t is determined by the neutron instrumentation system using the signal from the detector 18.

The control officer angle L-6 degrees after the start of load tracking, which was obtained in the predictive calculation human power optimization device 22 as described above, is the data input value 1: end! Core reactivity change and ratio +iL predicted and calculated based on human-powered take from 1628
I can do it. If the two match, it is refreshing to know that the predictor 39 was working correctly and the human operator used for the predictor 15'1- was also correct. Shigashi 7, output coefficient etc.
It is a change in reactivity that changes with time, and in reality, it is the change in reactivity obtained from 11''1 in [Preliminary 311] and ffi! Generally, there is a deviation from the input reactivity, and when this deviation occurs, the manual take used for one predictor is corrected according to the procedure shown in Figure A4; 5.

In FIG. 5, -J'i+', +total 1-'Y manual optimization equipment-22 calculates the predicted and calculated core reactivity change Δ as described above, and r. And the actual′! 1j14 Calculate the absolute value of the difference between the input reactivity performance ΔKcoNr and determine whether or not the difference between ΔKcoNr and ΔKcoNr is larger than the predetermined profit condition α, iΔ, C0NT−Δ, r, l <α Sharpening is data human power ′j 1 stroke! ■Foreign information entered into the terminal device 28, 1
Calculate that the correct take for iJj calculation is S↑−
In addition to displaying it on the device 26, the pointer is also displayed on the device 26.
- 30 also transmitted, data input Jj type,...: ¥ Wait 1 Office 2
Based on the take from 8, δ'' commands 71 to remove the body voice and increase the resident speed to 1 C).

On the other hand, if 1ΔKcoy+r−ΔKenrc l >α
When , the next move is 11) City is -1; 6jjjjj
・1 “Analysis human power 1] Make the decision and data human power ψ;
Correct the manual input to the equipment base 28. -In addition,
This child υ! [In Kei I, calculations can be carried out at any time by the reactor personnel, and depending on the state of the reactor], the termination decision can be made at any time. Almost the following 3
It can be divided into two categories. In the case of hemp 1 (・, it is the flow shown in ■ in Figure 5, and the output is changed), j14i is used, and the output 1j + 'j is below after the start of daily load tracking. Applicable to The second combination is shown in (■) in FIG. 5, and is applied when the engine is operated with the night HH4) H'h force maintained constant after the start of daily load tracking. The third case is the lifting platform shown in ■ in FIG. The operation was carried out for a long time, and the ratio of
There will be a discrepancy between the calculated reaction degree and the result of 1 cup of li 111 input reaction degree! Applies to 'll'i case. Then each
The case will be explained in detail in 4(il).

■ For comparison when changing the output, the operation staff who reduced the auxiliary reactor output from the rated value of 10,066 to 80 in 30 minutes, t',, N coupling, d11] of the output coefficient of the phase input The retouching is carried out as follows.9 However, it is assumed that the calculated values of xenon T↑property and Zamarium dynamic properties are correct.
We will explain a boat platform that corrects and calculates output coefficients that have a significant change in reactivity. The force coefficient l:Ij can be calculated from the following equation.

Δni'p -A1gC0NT (A1gx, -
i-ΔKs-) - (15) where, Δ■gu'P; Reactivity change due to power coefficient when changing the furnace output from 100% to 80% ΔKcoNT; Furnace output from 100 to 80φ in 30 minutes
fj when changed to; '2) Summerization of the reactivity by versenon'
A11. F-book! @mj i history) ΔKgm; Furnace output 100 da.: From 80 candies in 0 minutes.
Reactivity change meter by samarium when changing 9', A1t'(note/f:'A ilj used) As a result, output 1 thread force A9-final input monitor, )A1' Data terminal terminal device for human power Correction of the output coefficient manually applied to 28 1
The night is as follows.

f'(P) - (Δ,'p/ΔKp)X f(P)
...(16) Here, the reactivity due to the output coefficient when changing the furnace output from 100 cm to 80 cm, calculated using f'(P); output coefficient final input - ΔKP; initial output coefficient ftF) Change f (P); Output coefficient initial input value ■ In the case of constant output value comparison If the output is constant, no change in reactivity occurs due to the output coefficient. Therefore, in the operation control when the output is constant, the reactivity changes are only due to xenon and samarium. Moreover, since the change in samarium is minute, most of the change in reactivity is due to xenon. For example, the review of the xenon reactivity of the predictive analysis input after the reactor power is lowered to 50 inches and maintained for one hour can be determined by the following equation.

ΔKx, (50%, 1hr)==ΔKCON? (1”
) (ΔKp+ΔKs,)=ΔKCON?
...(17) That is, the xenon reactivity when the output is maintained at 50% for 1 hour is equal to ΔKCONT (controlled input reactivity by poison and control rod). In addition,
The xenon reactivity ΔKX6r′″1 at the rated output is determined by the following equation.

Xer at ΔKx, rat-□・ΔK CON? −
(18) Δ) (e where, The xenon reactivity ΔKx, rat at the rated output obtained from equation (18) becomes the final human power value for predictive analysis, that is, the corrected input value to be manually input to the terminal device 28 for inputting the data. As a result, as Δ1(x, r a t has been corrected, the flow shown in ■ in FIG.
8. Manpower.

■ In the case of long-term comparison, the output coefficient and xenon reactivity were correctly determined and corrected by slowing in ■ and ■ above. Even in the case of 1ξ5, a difference may occur between the predicted and calculated reactivity and the actual input reactivity due to long-term operation of the nuclear reactor. In such a case, it is necessary to reconsider the micro cross-sectional area of xenon, which causes a difference in continuous reactivity changes. This review was carried out by correcting the xenon micro cross-sectional area using the following formula as shown in Figure 5 (■), performing repeated calculations using the value of the correction term β as a parameter, and calculating the change in core reactivity and input input using the #F calculation. Compare the actual reactivity and find the β that the two curves have.

(+,'(Xe)−βX σ, (Xe)
-(19) where σ,'(Xe)i xenon micro absorption cross section correction value σ. (Xe); initial value of xenon micro absorption cross section β; The data is displayed on the device 26 and used as manual data on the terminal device 28 for inputting the data, and is also transmitted to the poison removal injection reference speed determining device 30, where a more accurate prediction calculation of the core reactivity is performed and a more optimized poison is generated. It is possible to realize daily load tracking using liquid poison without fluctuations in output distribution depending on the reference rate of removal and injection.

In a nuclear reactor, damage to a fuel rod can lead to a major accident, so it is essential to maintain the integrity of the fuel. For this reason, it is desirable to minimize the fluctuation in the fuel output during load following, and at the same time, at the rated output U4r, it is desirable that the local fuel output does not exceed a constant value of 1. Therefore,
In operation (bow:, control (distorting the output locally such as ZR), the number of operations and operating range of the wholesale system is It would be desirable to make the power smaller. This is a comparison.The output change pattern is as shown in Figure 6, when the rated output is 50
This is a case where the engine is operated at the rated output for 14 hours.

(J〆1 #6) As shown in the table, the number of times the output adjustment rod was driven on the second day after the load following start force was 35 times from 24 hours to 25 hours after the start of the load following start force, which lowers the output. However, in Shio 11 of this embodiment, the number of sounds was reduced to three times. 1. Conventionally, it was necessary to drive the motor 40 times during the period from 33 to 34 hours when the output was increased, but in this embodiment, the number of drives is reduced to four. Furthermore, in one day from 24 hours after the start of load tracking to 48 FRf, conventionally the output adjustment rod had to be driven 83 times, but in this embodiment, it was only driven 16 times. (It may be ~, but the output adjustment rod's movement range was also 75c.
rn, whereas in this embodiment the driving range is about 11 cm, which is very small. In this way, since the number of times the output adjustment rod is driven is small and the driving range is small, the health of the fuel near the output adjustment rod when following the daily load is significantly improved.

In addition, in this example, the human power required for predicting changes in core reactivity during load follow-up is optimized, so the load follow-up pattern is not limited to a constant one, but can also be used for arbitrary output cover patterns that arbitrarily change the output. This method has the advantage of being able to accurately predict the core reactivity for load following, and optimizing the reactivity input plan for the power control system. This means that by formulating a control rod or poison injection plan based on predictive calculations and operating according to this plan, the desired load change can be achieved.
Nuclear reactor operation can be made easier and more efficient.

FIG. 7 shows another embodiment of the present invention, showing an output control system for a pressurized water reactor.

In FIG. 7, the core 10 is connected to a coolant system 34,
Coolant is circulated by a circulation pump 36 provided in the coolant system 34. A chemical volume control system 38 is connected to the coolant thread 34 .

This chemical volume control system 38 is composed of a boric acid injection system 40 and a volume control system 42, and is capable of adjusting the boric acid concentration in the coolant. Further, the chemical volume control system 38 is connected to the reactor power control device 32, and plays the same role as the poison removal injection device 14 shown in FIG.

A control+1 drive and chemical volume control operation reference pattern determination device 44 corresponding to the poison removal injection reference speed determination device 30 shown in FIG. 2 is connected to the data human power terminal device 28. Load following can be performed using the input data for the pre-suppression meter Ω input from 28 and the optimal control rod drive and chemical volume control determined by the predictive calculation input optimization device 22. 1: Sea urchins are turning.

The details of the load following control in this example are almost the same as in the case of the heavy water reactor shown in Fig. 2, but in the case of the heavy water moderated reactor, the poison concentration detector in heavy water is used to detect the poison concentration. Measuring and predicting calculation human power optimization device 2
However, this embodiment differs in that the operating signal of the boric acid injection system 40 and the operating signal of the volume control system 42 are transmitted to the predictive calculation input optimization device 22. In addition, the output control by load following in this embodiment may be a control method mainly based on the chemical volume control system, taking fuel health into consideration at the discretion of the operator, or may be a control method based on the chemical volume control system, taking into account ease of operation. Adjustment control rods may be mainly used, and the lack of reactivity may be compensated for by chemical volume control.

〔Effect of the invention〕

As explained above, according to the present invention, when changing the output of a nuclear reactor, the predicted core reactivity is compared with the actual core reactivity after the output change, and the reactor is used for predictive calculation. By modifying the operating state quantities of the reactor, the output of the reactor can be made to accurately follow the output change pattern.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional control method for making the reactor output follow the daily load, and FIG. 2 is a diagram showing a control system of a second embodiment of the reactor output control method according to the present invention. FIG. 3 is a flowchart of implementation 51i for determining the poison removal injection speed by the poison removal injection reference speed determination device of the embodiment 1iiJ, and FIG. 4 is a correction of input data for predictive calculation in the predictive calculation input optimization device of the above embodiment. FIG. 5 is a flowchart of an embodiment showing details of the input take correction method in the predictive calculation manual optimization device; FIG. 6 is a diagram showing an example of daily load follow-up dose cover turn. , 7th
The figure is a simplified diagram without showing the control system of another embodiment of the nuclear reactor output control method according to the present invention. DESCRIPTION OF SYMBOLS 10... Core, 12... Heavy water circulation system, 14... Poison removal injection device, 18... Neutron detector, 20...
Poison concentration detector, 22 Predictive calculation input optimization device, 24 Control rod drive device, 28 Data manual terminal device, 30 Poison removal injection reference speed determination device, 32 ...Reactor power control device, 34...
Coolant system, 38...Chemical volume control system. 1 Agent Patent attorney Tatsuyuki Uunuma 1 Mouth speech Rη (FL Toji compilation 2 Meka 3 Idol ~ Saramaki Naoheto S Hollow sacrifice 6 n Or 9 to
2,000 Gin M (h?
)

Claims (1)

[Claims] 1. Input a predetermined reactor output change pattern into the control device, predict and calculate the change in core reactivity according to the output change pattern based on the operating state quantities of the reactor, and obtain the predicted change in core reactivity. In a nuclear reactor output control method that predicts the amount of poison in the moderator and controls the amount of poison, the actual core reactivity after the start of the output change is calculated, and the core reactivity of the reactor and the predicted core reactivity are calculated. The output of the nuclear reactor is characterized in that the operating state quantity of the nuclear reactor at the time of starting the output change is corrected by comparing the reactivity with the reactivity, and the amount of poison in the moderator is controlled based on the corrected operating state quantity. Control method.