JP2945906B1 - Core flow monitoring system - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To be able to accurately measure the flow rate of cooling water in a reactor core while maintaining good device performance at all times without being affected by long-term aging and aging in a pressure vessel. And it can be corrected as needed. SOLUTION: In a reactor core flow rate monitoring system of a boiling water reactor, a plurality of pump means are arranged around a core part in a reactor pressure vessel, and each pump means circulates cooling water to the core part. Narrow band in the pressure vessel, a narrow band furnace water level detector for detecting each of the broadband reactor water level, and a broadband reactor water level detector, and calculate the indicated difference of the reactor water level detected by each reactor water level detector A narrow-band / wide-band reactor water level indicator difference calculating device, a reactor water level indicator difference / core flow rate calculating device for calculating a core flow rate equivalent value from the indicator difference calculated by the narrow-band / wide-band reactor water level indicator difference calculating device, A core flow rate monitoring device based on a reactor water level difference that monitors the core flow obtained by the reactor water level difference / core flow rate calculation device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to boiling water in which a plurality of pump means are arranged around a core in a reactor pressure vessel, and each pump means circulates cooling water to the core. The present invention relates to a core flow monitoring system for a nuclear reactor.

[0002]

2. Description of the Related Art Conventionally, a boiling water reactor (B
In WR), a plurality of jet pumps are disposed around the lower part of the core as cooling means for the core provided in the reactor pressure vessel, and cooling water is circulated through the core using each jet pump. There are a conventional BWR as described above, and an improved BWR (ABWR) in which a recirculation pump is used in place of the jet pump. In a normal case, each cooling means according to these conventional systems includes a core. A core flow rate monitoring system is provided that measures the flow rate of cooling water in the unit and constantly monitors the operation state.

FIG. 6 is a configuration explanatory view schematically showing an outline of a core flow rate monitoring system in a conventional BWR.
FIG. 2 is a configuration explanatory view schematically showing an outline of a core flow rate monitoring system in an improved BWR (ABWR).

First, in the conventional BWR shown in FIG.
As is well known, a reactor pressure vessel (hereinafter, referred to as a pressure vessel) 1 has a built-in core 2 supported by a core support plate 3 and has a core 2 above the core 2. A steam-water separator 4 for separating moisture from high-pressure steam generated by supply of cooling water to the steam generator, and a steam dryer 5 for drying high-pressure steam from which moisture has been separated are sequentially arranged, and dried through the steam dryer 5. The high-pressure steam is taken out of the main steam nozzle 6 to the outside.

As a cooling means for the core portion 2 in the conventional BWR, a plurality of jet pumps (JPs)
Jet pumps 7 are provided, and using each of these jet pumps 7, a mixed water of the cooling water supplied by the water supply sparger 9 and the saturated water drain separated by the steam separator 4 is used. It is sent from the lower side into the core 2 and recirculated.

For the pressure vessel 1, as a means for measuring the pressure difference of the cooling water in the vessel, a narrow-band reactor water level detector (indicating a reactor water level at a target portion corresponding to each of them, based on the relationship of the measurement range). (LT, N / R) 11 and a broadband reactor water level detector (LT, W / R) 12 are provided. 14, the pressure head through the reference water column instrumentation pipe 16 via the condensation tank 15, and the variable water column instrumentation pipe 1 from each of the corresponding reactor water level meter liquid phase nozzles 17, 18 respectively.
By constantly measuring the pressure difference between the pressure head and the pressure heads 9 and 20, the pressure difference decreases when the reactor water level in the pressure vessel 1 rises and decreases when the reactor water level falls. Utilizing the relative relationship that the differential pressure increases, the differential pressure of the reactor water level at each target site is compared with two types of reactor water level gauges, that is, a narrow band reactor water level gauge (N / R) 21. It is a general form to display on each of the broadband reactor water level meter (W / R) 22.

Here, in the case of the core flow rate monitoring system attached to the conventional BWR having the above-described structure, the pump differential pressure of the jet pump 7 installed around the core 2 is squared with the pump discharge flow rate. The intended core flow rate is monitored by utilizing the characteristic of proportionality, and a jet pump differential pressure detector (DPT) 31 is provided for each of the jet pumps 7. Differential pressure detector 3
According to 1, the pump discharge flow rate is obtained by measuring the differential pressure of each corresponding pump, and each differential pressure signal (pump differential pressure signal) is sent to an arithmetic unit (jet pump differential pressure / core flow rate arithmetic unit) 32. The total pump discharge flow rate obtained in this way, in other words, the core flow rate of the cooling water to the core 2 can be constantly monitored by the monitoring device (core flow rate monitoring device by jet pump differential pressure) 33. It is.

Next, an improved BWR (ABW) shown in FIG.
R), the configuration inside the pressure vessel 1 is almost the same as that of the above-mentioned conventional BWR except that the same number of the respective cooling water recirculation pumps (RIPs) 8 are used instead of the respective jet pumps (JP) 7. Only the core flow monitoring system is different.

In other words, in the case of a core flow rate monitoring system attached to an improved BWR (ABWR), on the other hand, the pump differential pressure of the recirculation pump 8 is proportional to the square of the pump discharge flow rate for each pump operation state. The core flow rate is monitored by utilizing the characteristic described above, and a cooling water recirculation pump differential pressure detector (DPT) 41 similar to the conventional BWR is provided for each of the recirculation pumps 8. The operating state of each pump is determined by the differential pressure detector 4 based on a rotational speed signal (pump rotational speed signal) from a pump rotational speed detector (not shown).
An average differential pressure of the pump is obtained by the differential pressure signal (pump differential pressure signal) from the first pump, and these signals and a separately determined reactor water temperature (density) signal are calculated by an arithmetic unit (circulating pump differential pressure / core core). The flow rate is input to a flow rate calculation device 42, the core flow rate is calculated from the QH characteristics of the pump, and the core flow rate is monitored (core flow rate monitoring device based on circulating pump differential pressure) 4
3 enables constant monitoring.

On the other hand, the upper and lower differential pressures of the core support plate 3 are set to have a constant relationship with the core flow rate for each reactor power state, together with the monitoring of the core flow rate by the pump differential pressure of the recirculation pump 8. The core flow rate is monitored by utilizing the relative characteristics of the core support plate differential pressure detector (D
The differential pressure signal (core support plate differential pressure signal) detected by the P.T.) 51 and the reactor output signal etc., which are separately determined, are input to an arithmetic unit (core support plate differential pressure / core flow rate arithmetic unit) 52, and the core flow rate is calculated. Is calculated, and the core flow rate can be constantly monitored by the monitoring device (core flow rate monitoring device based on the core support plate differential pressure) 53.

[0011]

When the boiling water reactor according to each of the conventional systems described above is operated, both the conventional BWR and the improved BWR (ABWR) generate a flow rate at each part in the core and the flow rate. It is important to predict in advance the point where the relationship with the differential pressure slightly changes due to the long-term operation of the plant, and periodically confirm the validity of the core flow rate monitoring system based on the prediction.

In this case, regarding the validity check of the above-mentioned core flow rate monitoring system, it is necessary to accurately evaluate whether there is a long-term change over time or aging due to the relationship between the core flow rate and the generated differential pressure, and the influence on the core flow rate instruction. There is a need to.

[0013] The present invention has been made to meet such a conventional demand, and its object is to provide:
It is possible to accurately measure the cooling water core flow rate in the reactor core by maintaining good equipment performance at all times without being affected by long-term aging and aging in the pressure vessel. It is an object of the present invention to provide a core water flow monitoring system of a boiling water reactor which can be corrected by using the above method.

[0014]

In order to achieve the above object, according to the present invention, a plurality of pump means are arranged around a core in a reactor pressure vessel. In a core flow rate monitoring system of a boiling water reactor in which cooling water is circulated through a core portion by a pump means, a narrow band reactor water level detector for detecting each of a narrow band and a wide band reactor water level in the pressure vessel. , And a broadband reactor water level detector,
A narrow-band / wide-band reactor water level indicator difference calculating device for calculating an indicator difference of the reactor water level detected by each of the reactor water level detectors, and a core flow rate based on the indicator difference calculated by the narrow-band / wide-band reactor water level indicator difference calculating device. The apparatus includes a reactor water level indicating difference / core flow rate calculating device for calculating a corresponding value, and a core flow rate monitoring device based on a reactor water level indicating difference for monitoring a core flow obtained by the reactor water level indicating difference / core flow rate calculating device.

In the core flow rate monitoring system according to the present invention, the difference between the indicated value of the reactor water level from the narrow band reactor water level detector and the indicated value of the reactor water level from the broadband reactor water level detector is a narrow band / wide band reactor. After being calculated by the water level indicator difference calculation device, a reactor water level indicator difference / core flow rate equivalent value is calculated by the reactor water level indicator difference from the reactor water level indicator difference. It is monitored in a flow monitor.

According to a second aspect of the present invention, there is provided a boiling water reactor in which a plurality of pump means are arranged around a core in a reactor pressure vessel and cooling water is circulated through the core. In the core flow rate monitoring system, a narrow band reactor in the pressure vessel, a narrow band reactor water level detector for detecting each of a broadband reactor water level, and a broadband reactor water level detector, and the furnace detected by each of the reactor water level detectors Narrow band for calculating indication difference of water level /
A broadband reactor water level indicator difference calculating device, a reactor water level indicator difference / core flow rate calculating device for calculating a core flow rate equivalent value from the indicator difference calculated by the narrow band / broadband reactor water level indicator difference calculating device, and the reactor water level indicator difference / Core flow rate monitoring device based on reactor water level indicator for monitoring core flow rate obtained by core flow rate calculation device, core flow rate monitoring device based on the reactor water level indication difference, core flow rate monitoring device based on pump differential pressure separately provided, and core support plate The difference between the core flow rates from the core flow rate monitoring device based on the differential pressure is calculated, compared, recorded and monitored.
And a monitoring device.

In the core flow rate monitoring system according to the present invention, the difference between the indicated value of the reactor water level from the narrow band reactor water level detector and the indicated value of the reactor water level from the broad band reactor water level detector is a narrow band / wide band reactor. After being calculated by the water level indicator difference calculation device, a reactor water level indicator difference / core flow rate equivalent value is calculated by the reactor water level indicator difference from the reactor water level indicator difference. While being monitored by the flow monitoring device,
At the same time, the indicated value of the core flow rate, the indicated value of the core flow rate from the core flow rate monitoring device by the pump differential pressure, and the indicated value of the core flow rate from the core flow rate monitoring device by the core support plate differential pressure, It is compared and recorded and monitored by the recording / monitoring device based on the core flow rate instruction difference comparison.

According to a third aspect of the present invention, there is provided a boiling water reactor in which a plurality of pump means are arranged around a core in a reactor pressure vessel and cooling water is circulated through the core. In the core flow rate monitoring system, a narrow band in the pressure vessel, a plurality of narrow-band reactor water level detectors for detecting the respective reactor water levels at a plurality of required locations in a wide band, and a plurality of broadband reactor water level detectors, The average value of each reactor water level detected by each narrow-band reactor water level detector and each broadband reactor water level detector is calculated, and the average value of each reactor water level is calculated as necessary, the pressure in the furnace, the narrow-band reactor water level, and the like. Temperature, and a narrow band reactor water level average calculation / correction means for correcting based on various conditions such as a broadband reactor water temperature, and a broadband reactor water level average calculation / correction means, and the respective reactor water level average calculation / correction means Reactor water calculated or corrected A narrow-band / wide-band reactor water level indicator difference calculating device for calculating an indicator difference of an average value, and a reactor water level indicator difference / calculator for calculating a core flow rate equivalent value from the indicator difference calculated by the narrow-band / wide-band reactor water level indicator difference calculating device. Core flow rate calculation device,
A core flow rate monitoring device based on a reactor water level difference that monitors the core flow rate obtained by the reactor water level difference / core flow rate calculation device.

In the core flow rate monitoring system according to the third aspect, the average value of the indicated values of the reactor water level from the plurality of narrow-band reactor water level detectors and the indicated values of the reactor water level from the plurality of broadband reactor water level detectors is provided. Is calculated by the narrow-band reactor water level average calculation / correction means, and the broadband reactor water level average calculation / correction means, respectively.
And, if necessary, the average value of each reactor water level was corrected based on various conditions such as the furnace pressure, the narrow-band reactor water temperature, and the broadband reactor water temperature. After the difference between the average values is calculated by the narrow band / wide band reactor water level indicating difference calculating device, the core water flow equivalent value is calculated from the indicating difference of the reactor water level by the reactor water level indicating difference / core flow calculating device. Is monitored by the core flow rate monitoring device based on the reactor water level indication difference.

According to a fourth aspect of the present invention, there is provided a boiling water reactor in which a plurality of pump means are disposed around a core in a reactor pressure vessel and cooling water is circulated through the core. In the core flow rate monitoring system, a narrow band in the pressure vessel, a plurality of narrow-band reactor water level detectors for detecting the respective reactor water levels at a plurality of required locations in a wide band, and a plurality of broadband reactor water level detectors, The average value of each reactor water level detected by each narrow-band reactor water level detector and each broadband reactor water level detector is calculated, and the average value of each reactor water level is calculated as necessary, the pressure in the furnace, the narrow-band reactor water level, and the like. Temperature, and a narrow band reactor water level average calculation / correction means for correcting based on various conditions such as a broadband reactor water temperature, and a broadband reactor water level average calculation / correction means, and the respective reactor water level average calculation / correction means Reactor water calculated or corrected A narrow-band / wide-band reactor water level indicator difference calculating device for calculating an indicator difference of an average value, and a reactor water level indicator difference / calculator for calculating a core flow rate equivalent value from the indicator difference calculated by the narrow-band / wide-band reactor water level indicator difference calculating device. Core flow rate calculation device,
A core flow rate monitoring device based on a reactor water level indicator for monitoring a core flow obtained by the reactor water level indicator / core flow rate calculation device, a core flow rate monitoring device based on the reactor water level indicator difference, and a core flow rate monitoring device based on a pump differential pressure provided separately And a recording / monitoring device based on a core flow instruction difference comparison for comparing, calculating and recording / monitoring an instruction difference of each core flow from a core flow monitoring device based on a core support plate differential pressure.

In the core flow rate monitoring system according to the present invention, the average value of the indicated values of the reactor water level from the plurality of narrow-band reactor water level detectors and the indicated values of the reactor water level from the plurality of broadband reactor water level detectors is provided. Is calculated by the narrow-band reactor water level average calculation / correction means, and the broadband reactor water level average calculation / correction means, respectively.
And, if necessary, the average value of each reactor water level was corrected based on various conditions such as the furnace pressure, the narrow-band reactor water temperature, and the broadband reactor water temperature. After the difference between the average values is calculated by the narrow band / wide band reactor water level indicating difference calculating device, the core water flow equivalent value is calculated from the indicating difference of the reactor water level by the reactor water level indicating difference / core flow calculating device. The core flow rate is monitored by the core flow rate monitoring device based on the reactor water level indication difference, and at the same time, the core flow rate indication value, the core flow rate indication value from the core flow rate monitoring device based on the pump differential pressure, and the core support The core flow rate indication value from the core flow rate monitoring device based on the plate differential pressure is compared and recorded and monitored by a recording / monitoring device based on the core flow rate difference difference comparison.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an improved BWR according to the present invention will be described.
An embodiment of a core flow rate monitoring system that can be shared by the (ABWR) and the conventional BWR will be described in detail.

FIGS. 1 and 2 are schematic diagrams showing the outline of an improved BWR (ABWR) core flow rate measuring and monitoring system according to each of the first and second embodiments of the present invention. It is a block diagram which shows the aspect of the core flow rate monitoring part in 2nd Embodiment of FIG. 2 concretely. FIG.
Is an improved BWR according to a third embodiment to which the present invention is applied.
FIG. 5 is a block diagram showing a configuration of a main part of a core flow rate measuring and monitoring system of (ABWR), and FIG. 5 is a block diagram showing a detailed configuration of a reactor water level detection unit. In the apparatus configuration of each embodiment shown in FIGS. 1 to 5, the same parts as those in FIGS. 6 and 7 are denoted by the same reference numerals.

In each of the first and second embodiments, as shown in FIG. 1, FIG. 2, and FIG. 3, a core portion is provided in the pressure vessel 1 constituting the improved BWR (ABWR). The recirculation pumps (respective pump means) 10 are arranged around the lower side of the pump 2, and the recirculation pumps 8 supply the water supplied from the water supply sparger 9 and the steam-water separator 4.
The mixed water with the saturated water drain from the furnace is sent from the lower side of the core support plate 3 into the core portion 2 to be recirculated.

Similarly, as a means for measuring the pressure difference of the cooling water in the pressure vessel 1, the reference water column instrumentation pipe 1 through the steam phase pipe 14 and the condensation tank 15 from the reactor water level steam phase nozzle 13 is used.
6 and the pressure nozzles 17 and 1
The narrow-band reactor water level detector (LT, N / R) 11 and the wide-band reactor water level detector (L) which constantly detect the pressure difference from the pressure head through the variable water column instrumentation pipes 19 and 20 respectively.
T, W / R) 12, and in this case, a reactor water level gauge vapor phase nozzle 13, and each furnace water level gauge liquid phase nozzle 17,
18 is opened to a sufficiently wide flow path in the pressure vessel 1 so as not to be affected by the flow path wall shape or the like, and each of the water level detectors 11 and 12 detects Each reactor water level gauge corresponding to the differential pressure of the reactor water level,
Narrow band reactor water level meter (N / R) 21 and broad band reactor water level meter (W /
R) 22.

Further, as a core flow rate monitoring system for monitoring the core flow rate, a part of the system is constituted, and on the other hand, a cooling water recirculation pump differential pressure detector ( DPT) 41, an operating state signal of each pump is provided by a rotation speed signal (pump rotation speed signal) from each corresponding pump rotation speed detector, and a differential pressure signal (pump) from the differential pressure detector 41 is provided. The average differential pressure of each pump is obtained by the differential pressure signal), and these signals and the reactor water temperature (density) signal and the like are input to an arithmetic unit (circulating pump differential pressure / core flow rate arithmetic unit) 42 and the core The flow rate is calculated and the core flow rate can be constantly monitored by a monitoring device (core flow rate monitoring device based on circulating pump differential pressure) 43. On the other hand, the difference detected by a core support plate differential pressure detector (DPT) 51 is detected. Pressure signal (core The core plate differential pressure signal) and the reactor output signal are input to an arithmetic unit (core support plate differential pressure / core flow rate arithmetic unit) 52 to calculate the core flow rate and monitor the core flow rate (core support plate). Core flow rate monitoring device based on differential pressure)
This is exactly the same as the case where the monitoring can be performed at all times by 53.

Here, in the case of the first and second embodiments having the above-described configurations, the vapor phase section of the pressure vessel 1 is provided for each of the narrow-band and wide-band reactor water level detectors 11 and 12. Although the reference water column instrumentation piping 16 from the furnace water level vapor phase nozzle 13 which is opened at the same time is connected in common, the variable water column instrumentation pipings 19 and 20 are narrowed according to the requirements of their respective measurement ranges. The furnace water level gauge liquid phase nozzle 17 of the zone furnace water level detector 11 is opened above the water supply sparger 9,
The reactor water level gauge liquid phase nozzle 18 of the broadband reactor water level detector 12 is opened considerably below the water supply sparger 9.

As a result of this arrangement, the flow of the cooling water in the pressure vessel 1 at the openings of the reactor water level gauge liquid phase nozzles 17 and 18 is determined by the reactor water level gauge liquid phase nozzle of the narrow band reactor water level detector 11. While the flow velocity is almost zero on the opening side of the furnace 17, the liquid level nozzle 18 of the reactor water level meter of the broadband reactor water level detector 12 is used.
On the opening side, the mixed water of the supply water from the water supply sparger 9 and the saturated water drain from the steam separator 4 is sent into the core portion 2 as the core flow rate by each recirculation pump 8. Therefore, the flow rate is affected by the increase / decrease of the core flow rate. That is, since the reactor water level meter liquid phase nozzle 18 of the broadband reactor water level detector 12 is open to the flow velocity existing portion in the pressure vessel 1 as described above, the pressure head in the variable water column instrumentation pipe 20 is: Under the influence of the increase and decrease of the flow velocity, the increase and decrease of the static pressure occur as is clear from Bernoulli's theorem.
The detected value of the reactor water level differential pressure due to 2 fluctuates.

On the other hand, as described above, the broadband reactor water level detector 12 greatly affected by the flow rate of the cooling water in the pressure vessel 1
On the other hand, since the narrow-band reactor water level detector 11 is hardly affected by the flow rate of the cooling water, the improved BWR (ABW
In the normal operation state of R), a difference is generated between the reactor water level indication of the narrow-band reactor water level gauge 11 and the reactor water level indication of the broad-band reactor water level gauge 12, and the reactor water level indication value of the narrow-band reactor water level gauge 11 is obtained. The indicated value of the reactor water level of the broadband reactor water level gauge 12 is lower than that.
Since the indicated difference in the furnace water level increases and decreases in accordance with the flow rate of the cooling water in the pressure vessel 1, the flow rate can be measured relatively accurately and easily by the indicated difference in the furnace water level. If the flow rate of the cooling water can be confirmed in this way, the internal flow rate of the cooling water, In other words, the core flow can be measured as accurately as possible.

Therefore, in the improved BWR (ABWR) core flow rate monitoring system according to the first embodiment shown in FIG. 1 of the present invention, the narrow-band reactor water level detection is performed in combination with the above-mentioned conventional system. The reactor water level differential pressure instruction signal detected by the detector (LT, N / R) 11 and the reactor water level differential pressure instruction signal detected by the broadband reactor water level detector (LT, W / R) 12 are respectively input. To calculate the indicated difference (a narrow band / wide band reactor water level indicated difference calculating unit) 61
And an arithmetic unit (reactor water level instruction difference / core flow rate arithmetic unit) 62 for calculating a flow velocity / core flow rate equivalent value corresponding to the reactor water level instruction difference of the arithmetic unit 61 are sequentially provided. The core flow rate can be constantly monitored by the monitoring device (core flow rate monitoring device based on the reactor water level indication difference) 63.

Therefore, the improved B according to the first embodiment
In the case of WR (ABWR) core flow rate monitoring system,
After the difference between the indicated value of the reactor water level from the narrowband reactor water level detector 11 and the indicated value of the reactor water level from the broadband reactor water level detector 12 is calculated by the arithmetic unit 61, The equivalent value of the core flow rate is calculated by the arithmetic unit 62, and the core flow rate obtained as a result of each of these calculations is calculated by the
Can be easily monitored in this case, in this case,
Since the measurement and detection points of each reactor water level have a particularly wide flow path cross-sectional area, the long-term core flow rate-generated differential pressure characteristics of the device itself are not affected by aging, aging, etc. As a result, an accurate core flow rate can always be grasped.

Further, in the core flow rate monitoring system of the improved BWR (ABWR) according to the second embodiment shown in FIG. 2 of the present invention, in addition to the configuration of the first embodiment, FIG.
As shown in summary, the instruction signal of the core flow rate from the monitoring device (core flow rate monitoring device based on the difference in the reactor water level) 63 and each monitoring device according to the conventional method described above, that is, the monitoring device (circulation pump) Core flow rate monitoring device by differential pressure) 4
3. A recording / monitoring device that inputs an instruction signal of each core flow rate from a monitoring device (core flow rate monitoring device based on a core support plate differential pressure) 53, compares these instruction signals with each other, calculates and records the signals. (Recording / monitoring device based on core flow rate instruction comparison) 71 is provided.

Therefore, the improved B according to the second embodiment
In the case of WR (ABWR) core flow rate monitoring system,
In addition to obtaining the same operation and effect as the first embodiment, an instruction value of the core flow rate from the core flow rate monitoring device 63,
The respective values of the core flow rates from the core flow rate monitoring devices 43 and 53 according to the conventional method are compared with each other and recorded and monitored by a recording / monitoring device.
Based on the monitoring, it is possible to confirm the aging, aging, etc. of the device itself, and it can also be used for correction and the like if necessary.

Next, the improved BWR (ABWR) core flow rate monitoring system according to the third embodiment shown in FIGS. 4 and 5 of the present invention is similar to the apparatus configuration according to the first and second embodiments described above. A plurality of narrow-band reactor water level detectors 11 for detecting the respective reactor water levels at a plurality of required locations in a narrow band and a wide band in the pressure vessel 1, and a plurality of broadband reactor water level detectors 12 are similarly provided. For each of the narrow band reactor water level detectors 11, an N / R average value calculation circuit 81 for calculating the average value of each detected narrow band reactor water level is provided. On the other hand, by providing a W / R average value calculating circuit 82 for calculating the average value of the detected wide- and narrow-band reactor water levels, the average value of each of these narrow-band reactor water levels (or each corrected narrow-band reactor water level described later) is obtained. Zone furnace water level average) The average value of the zone water level (the average value of each narrow-band reactor water level corrected in the same manner) is processed by the arithmetic unit (narrow-band / wide-band reactor water level instruction difference arithmetic unit) 61 to indicate the difference between the two. Then, the difference between the furnace water level average values is obtained, and thereafter, the same operation as described above is performed.

That is, in the case of the improved BWR (ABWR) core flow rate monitoring system according to the third embodiment, the indicated value of each narrow-band reactor water level in each of the first and second embodiments described above. Instead of using the indicated value of each broadband reactor water level, the average value of each narrowband reactor water level and the average value of each broadband reactor water level are used, so that a more accurate core flow rate can be obtained and its monitoring becomes possible. is there.

In the third embodiment, as shown in FIG. 5, the reactor pressure detector 83 compares the average value of each narrow-band reactor water level and the average value of each broad-band reactor water level with each other. Reactor pressure to be corrected based on the reactor pressure detection signal of
Density correction circuits 84 and 85, and each instrumentation pipe ambient temperature / density correction circuit 8 that performs correction based on a temperature detection signal from a temperature detector 86 that detects the temperature inside each instrumentation pipe 19 or 20.
7 and 88, and a reactor water subcool temperature / reactor water density correction circuit 90 for correcting the average value of each reactor water level based on the reactor water temperature detection signal from the reactor water temperature detector 89. And an N / R average value calculation circuit 91 and a W / R average value calculation circuit 92 for making corrections based on detection signals from other reactor water level detectors (not shown).
By providing the N / R reactor water level correction / averaging signal 93 and the W / R reactor water level correction / averaging signal 94, these corrected average values can be properly used as necessary. In this case, a more accurate core flow rate can be obtained and monitored by using the corrected average value of each reactor water level.

In each of the above embodiments, the case where the present invention is applied to the improved BWR (ABWR) core flow rate monitoring system has been described. However, the same or almost the same applies to the conventional BWR core flow rate monitoring system. It can be applied in the same way, with similar or almost similar actions,
The effect is obtained.

[0038]

As described above in detail in each embodiment, according to the core flow rate monitoring system of the first aspect of the present invention, the indicated value of the reactor water level by the narrow band reactor water level detector and the detection of the broadband reactor water level are provided. The difference between the reactor water level indicated by the filter and the
After calculating by a broadband reactor water level indicating difference calculating device and obtaining a core flow rate by the reactor water level indicating difference / core flow rate calculating device from the indicating difference of the reactor water level, the core flow rate is calculated by a core flow rate monitoring device based on the reactor water level indicating difference. I've been monitoring it,
Compared with the conventional core flow rate monitoring system, there is no danger of being affected by long-term aging, aging, and the like, and there is an excellent feature that an accurate core flow rate can always be obtained.

According to the core flow rate monitoring system of the second aspect of the present invention, the difference between the indicated value of the reactor water level by the narrow band reactor water level detector and the indicated value of the reactor water level by the broadband reactor water level detector is determined by the narrow band / Calculated by the wide-band reactor water level difference calculator,
After obtaining the core flow rate by the reactor water level difference / core flow rate calculation device from the reactor water level difference, the core flow rate is monitored by a core flow rate monitoring device based on the reactor water level difference. The difference between the indicated value, the indicated value of the core flow rate from the core flow rate monitoring device based on the pump differential pressure in the conventional method, and the indicated value of the core flow rate from the core flow rate monitoring device based on the differential pressure of the core support plate is referred to as the core flow rate difference. Since the comparison and recording / monitoring are performed by the recording / monitoring device by comparison, the same operation and effect as those in the first embodiment can be obtained. There is an advantage that it is possible to check the aging, secular change, etc.

According to the core flow rate monitoring system of the third aspect of the present invention, an instruction value of the reactor water level from each of the plurality of narrow-band reactor water level detectors and an instruction of the reactor water level from each of the plurality of broadband reactor water level detectors. The average value and the average value of each reactor water level are calculated by the narrow-band reactor water level average value calculation / correction means and the broadband reactor water level average value calculation / correction means, respectively, and the average value of each Correction based on various conditions such as zone reactor water temperature and broadband reactor water temperature, and furthermore, the difference between each reactor water level average value,
Alternatively, the difference between the corrected average values is calculated by a narrow-band / wide-band reactor water level indicating difference calculating device, and the core is calculated by the reactor water level indicating difference / core flow rate calculating device from the reactor water level average value or the corrected average value indicating difference. After obtaining the flow rate, this core flow rate is monitored by the core flow rate monitoring device based on the difference in the reactor water level. In addition to the operation and effect in the first embodiment, here, the average of each reactor water level is used. The use of the value, or the corrected average, results in a more accurate and accurate core flow rate.

According to the core flow rate monitoring system of the present invention, the reactor water level indication value from each of the plurality of narrow band reactor water level detectors and the reactor water level indication from each of the plurality of broadband reactor water level detectors. The average value of each reactor water level is calculated by the narrow-band reactor water level average calculation / correction means and the broadband reactor water level average calculation / correction means. It is corrected based on various conditions such as the zone water temperature and the broadband reactor water temperature, and the difference between each reactor water level average value or the difference between the corrected average values is calculated by the narrowband / wideband reactor water level indication difference calculation device. After calculating and obtaining the core flow rate from the indicated difference of the reactor water level average value or the corrected average value by the reactor water level instruction difference / core flow rate calculating device, the core flow rate is measured by the reactor flow level indicator. To be monitored by The core flow indication value, the core flow rate indication value from the core flow rate monitoring device based on the pump differential pressure in the conventional method, and the core flow rate indication value from the core flow rate monitoring device based on the core support plate differential pressure are compared with each other. Since the comparison and recording / monitoring are performed by the recording / monitoring device based on the flow rate instruction difference comparison, in addition to the operation and effect in the second embodiment, here, the average value of each reactor water level or the corrected Since the average value is used, a more accurate and accurate core flow rate can be obtained.

[Brief description of the drawings]

FIG. 1 shows an improved BWR (ABW) according to a first embodiment.
FIG. 1 is a configuration explanatory view schematically showing an outline of a core flow rate monitoring system of R).

FIG. 2 shows an improved BWR (ABW) according to a second embodiment;
FIG. 1 is a configuration explanatory view schematically showing an outline of a core flow rate monitoring system of R).

FIG. 3 is a block diagram specifically showing an aspect of a core flow rate monitoring unit in the second embodiment of FIG. 2;

FIG. 4 shows an improved BWR (ABW) according to a third embodiment;
FIG. 2 is a block diagram showing a main configuration of a core flow rate monitoring system of R).

FIG. 5 is a block diagram showing a detailed configuration of a reactor water level detection unit in FIG. 4;

FIG. 6 is a configuration explanatory view schematically showing an outline of a core flow rate monitoring system in a conventional BWR.

FIG. 7 is a configuration explanatory view schematically showing an outline of a core flow rate monitoring system in an improved BWR (ABWR).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel 2 ... Core part 3 ... Core support plate 4 ... Steam / water separator 5 ... Steam dryer 6 ... Main steam nozzle 7 ... Jet pump 8 ... Recirculation pump 9 ... … Water supply sparger 11… narrow-band furnace water level detector 12… broad-band furnace water level detector 13… furnace water level gauge vapor phase nozzle 14… vapor phase piping 15… condensing tank 16… standard water column instrumentation piping 17, Reference numeral 18: Furnace water level meter liquid phase nozzle 19, 20: Variable water column instrumentation pipe 21: Narrow band furnace water level meter 22 ... Broadband furnace water level meter 31 ... Jet pump differential pressure detector 32 ... Calculation device (jet pump differential) Pressure / core flow rate calculating device 33 ... monitoring device (core flow rate monitoring device by jet pump differential pressure) 41 ... cooling water recirculation pump differential pressure detector 42 ... calculating device (circulating pump differential pressure / core flow rate calculating device) 43) Monitoring device (circulation) Core flow rate monitoring device by pump differential pressure) 51: Core support plate differential pressure detector 52: Calculation device (core support plate differential pressure / core flow rate calculation device) 53: Monitoring device (core flow rate by core support plate differential pressure) Monitoring device 61 Computing device (narrow band / broadband reactor water level indicator difference computing device) 62 ... Computing device (reactor water level indicator difference / core flow rate computing device) 63 ... Monitoring device (core flow monitoring by reactor water level indicator difference) 71) Recording / monitoring device (recording / monitoring device based on comparison of core flow rate instructions) 81 N / R average value calculation circuit 82 W / R average value calculation circuit 83 Reactor pressure detector 84 , 85: Reactor pressure / density correction circuit 86: Temperature detector 87, 88: Instrumentation piping ambient temperature / density correction circuit 89: Reactor water temperature detector 90: Reactor water subcool temperature / reactor water density correction circuit 91 N / R average calculation Circuit 92 ...... W / R average value calculating circuit 93 ...... N / R reactor water level correction / averaged signal 94 ...... W / R reactor water level correction / averaged signal

Continuation of the front page (56) References JP-A-9-281274 (JP, A) JP-A-9-133782 (JP, A) JP-A-9-72987 (JP, A) JP-A-5-302840 (JP, A) , A) JP-A-60-13287 (JP, A) JP-A-59-60393 (JP, A) UTSUNO Het. al. , "Measuring Method for ABWR Core Flow Rate." Nucl. Sci. Technol. , Vol. 30, No. 9 , P. 946-955 (1993) (58) Field surveyed (Int. Cl. ⁶ , DB name) G21C 17/032 GDB G01F 1/00 JICST file (JOIS)

Claims (4)

(57) [Claims] 1. A boiling water reactor core flow rate monitoring system for arranging a plurality of pump means around a core part in a reactor pressure vessel and circulating cooling water to the core part, wherein: A narrow-band reactor water level detector for detecting each of the narrow-band and wide-band reactor water levels, and a broad-band reactor water level detector; and a narrow-band / wide-band that calculates an instruction difference between the reactor water levels detected by the respective reactor water level detectors. A reactor water level indicator difference calculator, a reactor water level indicator difference / core flow rate calculator for calculating a core flow rate equivalent value from the indicator difference calculated by the narrow band / broadband reactor water level indicator difference calculator, and the reactor water level indicator difference / A core flow rate monitoring system, comprising: a core flow rate monitoring device based on a reactor water level indication difference for monitoring a core flow rate obtained by a core flow rate calculation device. 2. A boiling water reactor core flow rate monitoring system for arranging a plurality of pump means around a core portion in a reactor pressure vessel and circulating cooling water to the core portion, wherein: A narrow-band reactor water level detector for detecting each of the narrow-band and wide-band reactor water levels, and a broad-band reactor water level detector; and a narrow-band / wide-band that calculates an instruction difference between the reactor water levels detected by the respective reactor water level detectors. A reactor water level indicator difference calculator, a reactor water level indicator difference / core flow rate calculator for calculating a core flow rate equivalent value from the indicator difference calculated by the narrow band / broadband reactor water level indicator difference calculator, and the reactor water level indicator difference / A core flow rate monitoring device based on a reactor water level indicator for monitoring a core flow rate obtained by a core flow rate arithmetic device, a core flow rate monitoring device based on the reactor water level indicator difference, a core flow rate monitoring device based on a pump differential pressure provided separately, and a core support plate difference By pressure Core flow monitoring system, characterized in that it comprises a recording and monitoring system according to the core flow rate indication difference compared to record and monitor the instruction difference calculated comparison of the core flow rate from the core flow rate monitoring device. 3. A core water flow monitoring system for a boiling water reactor in which a plurality of pump means are disposed around a core portion in a reactor pressure vessel and a cooling water is circulated through the core portion. Narrowband, a plurality of narrowband reactor water level detectors to detect each of the required plurality of reactor water levels in a wideband, respectively, and a plurality of broadband reactor water level detectors, each of the narrowband reactor water level detector, and The average value of each reactor water level detected by the broadband reactor water level detector is calculated individually, and the average value of each reactor water level is calculated as necessary, such as the furnace pressure, the narrow-band reactor water temperature, and the broadband reactor water temperature. Narrow band reactor water level average value calculation / correction means to correct based on various conditions, and broadband reactor water level average value calculation / correction means, Calculated or corrected by each of the reactor water level average value calculation / correction means Narrow band for calculating the indicated difference of each reactor water level average Zone / broadband reactor water level indicator difference calculating device; a reactor water level indicator difference / core flow rate calculating device for calculating a core flow rate equivalent value from the indicator difference calculated by the narrow band / broadband reactor water level indicator difference calculating device; A core flow rate monitoring system, comprising: a core flow rate monitoring device based on a reactor water level direction difference for monitoring a core flow rate obtained by an instruction difference / core flow rate calculation device. 4. A boiling water reactor core flow rate monitoring system in which a plurality of pump means are arranged around a core portion in a reactor pressure vessel and a cooling water is circulated through the core portion, wherein: Narrowband, a plurality of narrowband reactor water level detectors to detect each of the required plurality of reactor water levels in a wideband, respectively, and a plurality of broadband reactor water level detectors, each of the narrowband reactor water level detector, and The average value of each reactor water level detected by the broadband reactor water level detector is calculated individually, and the average value of each reactor water level is calculated as necessary, such as the furnace pressure, the narrow-band reactor water temperature, and the broadband reactor water temperature. Narrow band reactor water level average value calculation / correction means to correct based on various conditions, and broadband reactor water level average value calculation / correction means, Calculated or corrected by each of the reactor water level average value calculation / correction means Narrow band for calculating the indicated difference of each reactor water level average Zone / broadband reactor water level indicator difference calculating device; a reactor water level indicator difference / core flow rate calculating device for calculating a core flow rate equivalent value from the indicator difference calculated by the narrow band / broadband reactor water level indicator difference calculating device; A core flow rate monitoring device based on a reactor water level indicator difference for monitoring a core flow rate obtained by an indicator difference / core flow rate calculation device; a core flow rate monitoring device based on the reactor water level indicator difference; a core flow rate monitoring device based on a pump differential pressure separately provided; A core flow rate monitoring system, comprising: a core flow rate difference difference recording / monitoring device for calculating and comparing and recording / monitoring an instruction difference of each core flow rate from a core flow rate monitoring device based on a support plate differential pressure.