System, method and program for monitoring reactor core

Field of the Invention

The invention relates to a technology for monitoring nuclear reactor cores.

State of the art

The reactor core monitoring system in nuclear power plants has many functions to calculate reactor core operating data, such as power distribution, to monitor the reliability of the reactor core. In one example, the monitoring reactor core operating data, calculated over a one hour cycle or at the operator's request, includes thermal limits, power distribution, and burn-out.

Here, the thermal threshold indicates an instantaneous value indicating that the fuel in the reactor core has no excess power increase and that cooling using cooling water is sufficient. Burning represents the integral value obtained by multiplying the thermal power of the reactor core by time. Burning represents the amount of nuclear fuel consumed.

In order to reduce the amount of work required to control the power plant, various controls are performed to control the operation of control tools as control rods to automate their operation. For example, there is a known thermal limit monitoring device for advanced boiling water reactors (ABWR), which calculates thermal limits for automatic control of rod operation based on short cycle times of 200 ms (see: Japanese Patent No. 06148376).

The results of calculating the thermal limit monitor are known to be too cautious. Therefore, in order to avoid unnecessary interception of control rods, the calculation results are adjusted by periodic calculations using the reactor core operating data as input data from the reactor core monitoring system in order to accurately detect the change in electrical status. . This adjustment cycle should be 5 minutes or less. Thus, it is necessary to shorten the reactor core life cycle computation cycle, which is typically 1 hour.

However, if the conventional reactor core monitoring system only shortens the computation cycle time without changing the reactor core operating algorithm, the burnout increase, which is the integrated value of the reactor core thermal power calculated from the integrated value between the current design value and the last design value, decreases. . As a result, the magnitude of the gain decreases and, at the same time, significant numbers can be eliminated when the burnout gain data is distributed in three-dimensional space, where the data has about 20,000 pixels for other calculations, such as isotope weighting. As a result, the accuracy of isotope weighting, which is calculated by distributing burnout data in 3D, may be impaired.

Brief description of the drawings

FIG. 1 is a functional diagram showing a first embodiment of a reactor core monitoring system in accordance with the present invention;

FIG. 2 is a block diagram showing the operation of a reactor core monitoring system according to a first embodiment of the present invention;

FIG. 3 is a functional diagram showing a second embodiment of a reactor core monitoring system in accordance with the present invention;

FIG. 4 is a block diagram showing the operation of a reactor core monitoring system according to a second embodiment of the present invention;

FIG. 5 is a functional diagram showing a third embodiment of a reactor core monitoring system according to the present invention;

FIG. 6 is a block diagram illustrating the operation of a reactor core monitoring system according to a third embodiment of the present invention; and

FIG. 7 is a functional diagram showing the structure of an automation system for operating the control rods in a reactor core monitoring system according to a third embodiment of the present invention.

Detailed Description of the Invention

First fulfillment

The present invention will be further described with reference to the drawings.

As shown in Figs. 1, the reactor core monitoring system 10 according to a first embodiment comprises: an information retention portion 20 for holding a continuous cycle T1 and a short cycle T2 as calculation information for the reactor core operating data X; a signal processing part 30 for generating heat balance data H based on the process signal P; Data Collection Part 41 for the continuous cycle heat balance data H and the reactor core operating data X, calculated at an earlier time point of the continuous cycle T1, at the same time as the heat balance data (H) and reactor core operating data were collected ( X) last calculated at short cycle T2 which is asynchronous for continuous cycle T1; and data calculation part 42 for calculating new reactor core operating data X, based on the collected reactor core operating data X and heat balance data H.

The information retention portion 20 retains continuous cycle information 21, short cycle information 22, and data storage address information 23.

For each activation time in a continuous cycle T1, from a predetermined initial activation time, information as a continuous cycle information 21 is retained in an information retention portion 20 where the continuous cycle T1 lasts, for example, 1 hour.

For each activation time in the short cycle T2, which is shorter than the continuous cycle T1, the information, like the short cycle information 22, is retained in the information retention portion 20 where the short cycle T2 lasts, for example, 10 minutes.

The continuous cycle T1 and its initial activation time in the continuous cycle information 21, as well as the short cycle T2 and its initial activation time in the short cycle information 22, may be determined optionally using the input portion 11. In addition, the short cycle information 22 may be changed using the input portion 11 so that activation of the short cycle T2 can be selectively initiated and stopped, and that the time intervals of the short cycle T2 can be alternated.

The processing activation portion 12 is required to activate the processing portion 40 for the continuous cycle information 21 and the short cycle information 22, the detention information portion 20, at a specified time. As described below, the processing detail of the processing section 40 is different depending on whether the processing section 40 is activated based on continuous cycle information (21) or is activated based on the short cycle information 22.

The storage address information 23 is the storage address information X of the calculated reactor core operating data in the data processing section 40. In the data processing part 40, the calculation of reactor core operating data X requires the current time heat balance data H and the previous time point calculated reactor core operating data X. Accordingly, the storage address X of previously calculated reactor core operating domains X is recorded in the information retention section 20. The data processing portion 40 receives heat balance data H at the time when the activation command from the processing activation section 12 is received. The data processing part 40 further accesses the data storage address information 23 and collects the reactor core operating data X from the data storage parts 51, 52.

As reactor core operational data X storage address information, reactor core operational data X time and file name can be used instead of storage address.

The signal processing portion 30 comprises an input portion 31 for input of process signals P such as reactor pressure, temperature, flow, control rod position, medium power range detector (APRM), and local power range detector (LPRM) signals, part of the calculation of thermal power

32, which calculates the heat balance data H based on the input process signals, and a storage section 33 for storing the calculated heat balance data H. The process signal input portion 31 accepts the process signal P input at intervals of about 5 seconds, while the thermal power calculation portion 32 calculates heat balance data H at intervals of about 15 seconds.

The data processing part 40 comprises the data acquisition part 41, the data computing part 42 and the data output part 43. The data processing part 40 performs the following processes, at times t1 to t6.

The continuous cycle T1 at time t4, the heat balance data H and the reactor core operating data Xn-1, which were calculated at the previous time period t1 of the continuous cycle T1, are collected in the data acquisition section 41, and the new reactor core operating data Xn is computed in the data calculation section. 42 and obtained from the data output part 43 are stored in the first data storage part 51.

Examples of reactor core operating data X are monitoring objects, which are essentially power distribution, thermal limits, and burnout.

The short cycle T2, which is asynchronous with the continuous cycle T1, at time t3, the heat balance data H and the reactor core operating data Xm-2, which were calculated last, are collected in data acquisition section 41, and the new reactor core operating data Xm-1. are calculated in the data computing part 42 and derived from the data output part 43 are stored in the second data storage part 52.

As described previously, processing of the short cycle T2, which is synchronous with the continuous cycle T1 at time t4, is preferred to the continuous cycle T1.

The short cycle T2, which is asynchronous with the continuous cycle T1, at time t5, the heat balance data H, and the reactor core operating data Xn, which were calculated last, are collected in the data acquisition section 41, and the new reactor core operating data Xm are computed. in the part 42 and obtained from the data output part 43 are stored in the second data storage part 52.

In the embodiment of the invention, the continuous cycle T1 is associated with a plurality of short cycles T2. Therefore, every third cycle, the time of the short cycle T2 is synchronized with the continuous cycle T1. However, the continuous cycle T1 need not be related to the short cycle T2 and the continuous cycle T1 need not be synchronized with the short cycle

T2.

In this way, the reactor core operating data (Xn-1, Xn) calculated at the time point (t1, t4) of the continuous cycle T1 is stored in the first part of the data storage 51. The short cycle T2 which is asynchronous to the continuous cycle T1 , t5, t6) the calculated reactor core operating data (Xm-2, Xm-1, Xm, Xm + 1) are stored in the second data storage section 52.

Therefore, the reactor core operating data Xm is stored at the short cycle time T2. However, since the reactor core operating data Xn calculated in continuous cycle T1 is presented there in a distributed form, an increase in the short cycle T2 calculation error is avoided.

For elements such as the thermal limits of the fuel that need to be monitored during the short cycle, the operating data of the short cycle reactor core stored in the first and second part of the data storage (51, 52) are used.

Therefore, the thermal limits can be calculated and corrected in a short cycle of, for example, 5 minutes, using the reactor core operating system reactor core operating data as initial values.

Elements such as burn-out, which receive a calculation error during short-cycle monitoring, use the continuous cycle reactor core operating data stored in the first storage portion 51.

Therefore, for the integrated value, there is a sufficient increase between the current calculation value and the previous calculation value. This makes it possible to calculate with sufficient accuracy the burn-out, which is an integral value of the thermal power of the reactor core.

Additionally, when burnout increase data, about 20,000 data points, is spread over three-dimensional space for another calculation, sufficient burnout increase does not allow significant digits to be erased. Therefore, the accuracy of isotope weighting is improved.

The following is a description of the operation of the reactor core monitoring system according to a first embodiment of the invention with reference to the block diagram of FIG. 2 (see Fig. 1 if necessary).

First, continuous cycle information 21 and short cycle information 22 are input from input portion 11 to information retention portion 20 (S11, S12). When it is not necessary to monitor reactor core operating data (X) during short cycle T2 (S13 No) based on continuous cycle information 21 is activated only in standard order (A).

In standard order A, the data acquisition portion 41 is activated at a time t4 of the continuous cycle (S15). The data acquisition part 41, from the process signal processing part 30 (S16), collects heat balance data H, and the first data storage part 51 (S17) collects the reactor core operating data Xn-1. In the data computing part 42, the reactor core operating data Xn is newly calculated (S18) and stored in the first data storage part 51 (S19).

When short cycle T2 occurs (S13 Yes), the need to monitor reactor core operating data X, together with standard procedure A based on continuous cycle information 21, is activated by standard procedure B based on short cycle information 22.

First, at time t4, when the continuous cycle T1 coincides with the short cycle T2 (S14 Yes), the standard order A is activated as previously described.

At time t5, when the continuous cycle T1 does not coincide with the short cycle T2 (S14 No), the heat balance data H is activated by the data acquisition section 41 from the process signal processing section 30 (S21). Since the last activation is a continuous cycle activation at time t4 (S22 Yes), the reactor core operating data Xn at time t5 is collected from the first data storage portion 51 (S23). In the data computation part 42, the reactor core operating data Xm is newly calculated in S24 and stored in the second data storage part 52 (S25).

Since the last activation is a short cycle activation at time t5 (S22 No), the reactor core operating data Xm at time t6 is collected from the second data storage portion 52 (S26). The reactor core operating data Xm + 1 is newly calculated (S24) in the data storage part 42 and is stored in the second data storage part 52 (S25).

The above standard procedure is repeated (S20 No, Yes) until the reactor core operating data (X) is completed.

Thus, in the reactor core monitoring system (10) according to the first embodiment of the present invention, the reactor core operating data of the previous time point for use in the calculation are selectively used in the continuous cycle and the short cycle, respectively. By calculating burn-out and the like, this allows for reduced error and improved accuracy when monitoring reactor core operating data based on short-term power plant fluctuations.

Second embodiment of the invention

A second embodiment of the invention is provided with reference to FIG. 3, a description of the reactor core monitoring system (10). The component parts of the drawing in Figs. 3, which are identical to those of FIG. 1 are denoted by identical reference numerals and duplicate descriptions thereof will be omitted.

A reactor core monitoring system 10 according to a second embodiment of the invention is provided with a data monitoring system 60 for evaluating new reactor core operating data X calculated in the data processing section 40 with reference to a threshold value.

The data monitoring portion 60 comprises a receiving portion 61 for receiving derived reactor core operating data X from a data processing portion 40, a data retention portion 62 for temporarily arriving received reactor core operating data X, and an evaluation portion 63 for receiving positive / negative decision based on the latest reactor core operating data X received in acceptance section 61, previous, the reactor core operating data X retained in the data retention section (62), and the threshold value in the retention value retention section (64).

When the decision part 63 is negative, the assessment is reported from the warning output part 66.

The following is a description of the operation of the reactor core monitoring system according to a second embodiment of the invention with reference to the block diagram of FIG. 4 (see Fig. 3 if necessary). Whereas in the block diagram Figs. The transition from S11 j to S14 and standard order A and B in Fig. 4 is similar to Figs. 2 corresponding transitions and standard procedures, duplicate descriptions will be omitted.

The data monitoring part 60, from the data processing part 40 to the receiving part 61 (S31), receives the reactor core operating data X. The data monitoring part 60 then obtains the amount of change between the last reactor core operating data and the previous reactor core operating data retained 62. In the event that the resulting change quantity is less than the threshold value (S32 Yes), a warning is output (S33). If the amount of change is less than the threshold value, no warning is output (S32 No).

In this way, when an alert is triggered by the amount of change above a set value as a threshold value, it becomes possible to see if the reactor core performance is changing rapidly. At the same time, the operator does not need to constantly monitor the output results, thereby achieving operator load reduction and rapid detection of any abnormalities at the power plant.

Third embodiment of the invention

A second embodiment of the invention is provided with reference to FIG. 3, a description of the reactor core monitoring system (10). In the drawing, FIG. 3 component parts identical to those of FIG. 1 are denoted by identical reference numerals and duplicate descriptions thereof will be omitted.

The reactor core monitoring system 10 according to a third embodiment is provided with a cyclic tuning portion 90 which initiates / stops short-cycle activation based on external information provided from the external means 80.

The external device 80 is particularly a device for monitoring the thermal limit. The thermal boundary monitoring device uses reactor core operating data (thermal boundary) calculated as baseline values ​​in the reactor core monitoring system 10 to compute a thermal threshold using a quantity of change in signal P in a short cycle using a correction operation.

Since the thermal limit of this adjustment operation is not accurate enough, the result of the calculation is derived to provide a cautious estimate.

When the thermal threshold obtained by this adjustment becomes greater than the threshold value, the automatic operation of the control rods is stopped and switched to manual control. Since the operation of adjusting the thermal boundary monitor is not accurate enough, as mentioned above, there have been cases where the automatic operation of the control rods has stopped even though the actual thermal boundary has not exceeded the threshold value.

Accordingly, in the reactor core monitoring system 10, the calculation cycle of the reactor core operating data (thermal limit) is shortened to prevent the accumulation of errors occurring during the thermal limit monitoring device adjustment operation.

The cyclic determination portion 90 comprises a reception portion 91 for receiving a thermal limit provided by a thermal limit monitoring device (external means 80) and an assessment acceptance portion 93 for judging whether the thermal threshold provided by the correction operation exceeded the threshold value in the retention portion 94. value.

The assessment of whether the thermal threshold has exceeded the threshold value is shown in the short-cycle information 22 (Fig. 1) in the information retention section 20, i.e., when the thermal threshold value does not exceed the threshold, the short-cycle activation may be stopped and exceeding the threshold value, the short cycle may be activated. In addition, many threshold values ​​can be provided and many short cycle time intervals can be rotated to optimize reactor core monitoring.

In addition, reactor core monitoring can be optimized not based on external information provided by external device 80, but by input of reactor core operating data derived from data processing section 40 into cycle setup portion (90) and switching a plurality of short cycle time intervals.

Although the thermal limit monitoring device deriving the thermal limit provided by the correction operation has been identified as an external device 80, the present invention is not limited to the disclosed construction. The status of the power plant can be estimated on the basis of the operating modes of the power plant and the information provided by the instrument providing the heat balance data H. When the evaluation results show that the power plant is not automatic and that the reactor power is low, short-cycle activation may be stopped, thereby reducing the load on the calculator.

Although it has been shown that the cycle detection portion 90 is located within the reactor core monitoring system, the placement of the cycle detection device 90 is not limited thereto. In the drawing, FIG. 7 shows the control rod automation system.

In the control rod automation system, the thermal boundary monitoring device 74 receives from the reactor core monitoring system 71, the nuclear measurement system 72, and the control rod operating monitoring system (73) process quantities such as thermal threshold (baseline), LPRM, APRM, and control. rod positions.

The thermal limit monitor 74 calculates thermal limits and values ​​of thermal conditions based on process quantities.

According to the calculation results, the thermal limit monitoring device 74 additionally outputs control signals such as an automation stop signal, control rod action takeover signal, and a core operation sequence takeover signal to an automatic power control device 75, control rod action monitoring system 76, and recirculation flow. management system 77.

In such an automation system for operating the control rods, the cycle setting portion 90 is located in the thermal limit monitoring device 74. The cycle setting portion 90 compares the calculated thermal limit of the thermal limit monitoring device 74 with the aforementioned threshold value.

The reactor core monitoring system 71 activates and stops the short cycle and switches its time intervals based on the evaluation results of the cycle detection portion 90 in the thermal limit monitoring device 74. As a result, an effect corresponding to that of a system in which the cycle setting portion 90 is housed in the reactor core monitoring system 71 can be achieved.

A reactor core monitoring system according to a third embodiment of the invention is provided with reference to the block diagram of FIG. 6 (if necessary, see Fig. 5), operating description. Since FIG. The transition j of S11, S12, S14, S31 in block diagram 6 to S33 and the standard order (A) and (B) are similar to j in Figs. 4 appropriate transitions and standard procedures, duplicate descriptions will be omitted.

The cycle setting portion 90 receives information to the receiving portion 91 (S41) from the external means 80. If the value of the received external information is greater than the threshold value (S42 Yes), the short cycle is activated and further processing (S43, standard order A and B) occurs. . Thereafter, if the value of the external information falls below the threshold value, the short-circuit activation is stopped (S42 No, Standard Order A).

In this way, based on the information sent from the external device 80, the short-cycle activation of the reactor core monitoring system 10 can be turned on and off. In the case where the thermal boundary monitoring device is selected as an external device, the reactor core monitoring system 10 is switched to short-cycle activation so that the amount of thermal boundary error accumulated during the correction operation can be reduced. This can reduce the likelihood of unnecessary stopping of the control rod automatic operation, thus reducing the operator's load.

In addition, since the short cycle is automatically activated when intensive monitoring is required, it is no longer necessary to overload the calculating machine.

According to the description provided, at least one embodiment of the present invention is intended to provide a reactor core monitoring technology that can calculate reactor core performance data in a very short cycle with high accuracy.

The present invention is not limited to those disclosed in the embodiments of the invention, and, subject to appropriate modifications, the present invention may be practiced within the scope of the common technical concepts.

The reactor core monitoring system may employ appropriate tools as appropriate computer functional programs. Also, the reactor core monitoring system can be controlled by a reactor core monitoring program formed by combining the respective functional programs.