• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    An embodiment of a neutron flux level calculator (90) includes: an analog signal processing device (10) that amplifies an AC component of a detector output signal from a neutron detector (2) and performs a filtering of a high frequency component; a digitizing device (20) which converts, with a certain sampling period, an output signal of the analog signal processing device (10) into a digital signal in time series; a wavelet analysis device (30) that performs the discrete wavelet transform using the time series digital signal to compute a wavelet coefficient; and a digital signal processing device (40) which calculates a mean squared value of the wavelet coefficients and converts the computed average squared value into a neutron flux level value.
    公开号:FR3021756A1
    申请号:FR1551661
    申请日:2015-02-26
    公开日:2015-12-04
    发明作者:Shigehiro Kono；Daijiro Ito；Hideyuki Kitazono
    申请人:Toshiba Corp；
    IPC主号:
    专利说明:

    [0001] NEUTRON FLUX LEVEL MEASUREMENT SYSTEM, NEUTRON FLUX LEVEL CALCULATOR AND NEUTRON FLUX LEVEL MEASUREMENT METHOD In its field, embodiments of the present invention relate to a neutron flux level measuring device, a neutron flux level calculator and a neutron flux level measurement method.
    [0002] In the background, neutrons produced in a fission reactor such as a light water reactor of a commercial nuclear power plant are measured using a fission chamber because of its excellent discrimination performance relative to with rays g. In a state in which the reactor power level is low, an output signal of the fission chamber is counted as pulse signals. When the reactor power level becomes high at a certain level, the pulse signals overlap each other, making it impossible to individually count the output signals of the fission chamber. Thus, a Campbell method that uses statistical fluctuation of the detector output signal is used to measure neutrons. In a fusion reactor, the duration of the nuclear fusion reaction (D-D reaction) of deuterium is increased by recent technical progress to increase the number of neutrons to be produced by the D-D reaction. Thus, it is necessary to use the fission chamber in a Campbell measurement zone 2 beyond a pulse measurement zone when the neutrons produced by the fusion reactor are measured. The accuracy of a result obtained from the measurement using the Campbell method is dependent on a time constant of an averaging circuit 5 at an output stage of a measuring device, and it is known that the greater the time constant, the higher the accuracy becomes. In the neutron measurement using the Campbell method, a calculation of the root mean square of the input signal is performed so as to calculate the statistical fluctuation of the detector output signal, so that the measurement is subject to a noise signal when the noise signal is superimposed on the input signal. In recent years, an inverter device that produces high frequency noise, for example, about 1 MHz is often used in a power supply device or electrical machine. In order to prevent high frequency noise from influencing the neutron measuring device, it is necessary to apply countermeasures, such as improving the shielding performance of a measuring device, and installing a ferrite core on a noise propagation path to the neutron measuring device.
    [0003] As countermeasures against noise, a conventional neutron measuring device comprises, on a signal processing circuit which processes the detector output signal (analog signal) from the neutron detector, a preamplifier, an amplifier alternating current, an analog filter, a squaring circuit, and a time constant applying circuit for applying a filter treatment to an input or output signal. However, it is difficult for a conventional analog filter or a digital filter to obtain perfect filtering characteristics and thus the influences of the noise can not be eliminated entirely. Such technologies are described in Japanese Patent Application Laid-Open No. 2007-240464, and Japanese Patent No. 5,159,645,302,176-3. A brief description of the drawings will now be made below. The Features and Advantages of The present invention will become apparent from the following description of specific exemplary embodiments thereof, given in connection with the accompanying drawings, of which: Figure 1 is a block diagram showing a configuration of a neutron flux level measurement according to a first embodiment; FIG. 2 is an algorithm representing a procedure for implementing the neutron flux level measurement method according to the first embodiment; Fig. 3 is a graph showing an example of a time evolution of the output signal of the neutron detector; Fig. 4 is a graph showing a result of the wavelet transformation; Fig. 5 is a graph showing a result of the wavelet transformation in a case in which a bandwidth is limited; Fig. 6 is a graph showing a result of wavelet transformation in a case in which bandwidth limitation and noise elimination are implemented; Fig. 7 is a block diagram showing a configuration of the neutron flux meter according to a second embodiment; Fig. 8 is a block diagram showing a configuration of the neutron flux level measuring device according to a third embodiment; Fig. 9 is a block diagram showing a configuration of the neutron flux level measuring device according to a fourth embodiment; Fig. 10 is a block diagram showing a configuration of a variant of the neutron flux level measuring device according to the fourth embodiment; Fig. 11 is a block diagram showing a configuration of the neutron flux level measuring device according to a fifth embodiment; and Fig. 12 is a block diagram showing a configuration of the neutron flux meter according to a sixth embodiment. The detailed description will now be given below. Embodiments of the present invention have been made to solve the above problem, and an object thereof is to rapidly achieve a measurement of a neutron flux level while eliminating noise influences. According to one embodiment, a neutron flux level calculator is provided comprising: an analog signal processing device which amplifies an AC component of a detector output signal from a neutron detector and realizes filtering for removing a high frequency component; a digitizing device which converts, with a certain sampling period, an output signal of the analog signal processing device into a digital time-series signal; a wavelet analysis device which performs a discrete wavelet transform using the time series digital signal to compute a wavelet coefficient; and a digital signal processing device which calculates a mean squared value of the wavelet coefficients and converts the calculated squared value into a neutron flux level value. Preferably, the wavelet analysis device comprises the wavelet transformation section which applies the discrete wavelet transform on the digital signal in time series using an orthonormal base to calculate the same number of wavelet coefficients as the number of digital signals in time series. Preferably, the digital signal processing device has a coefficient selecting / extracting section which selects, from a result of the calculation performed by the wavelet analysis device, the wavelet coefficient 3021756 - 5 - having a necessary frequency component, a root mean square calculating section which calculates the mean squared value of the coefficient selected by the coefficient selection / extraction section and a neutron flux level conversion section which converts the average squared value into a neutron flux level value. Preferably, the coefficient selection / extraction section is configured to selectively select a frequency range, and the neutron flux level conversion section is configured to perform a conversion for the selected frequency range.
    [0004] Preferably, the coefficient selection / extraction section is configured to changably select a time range, and the neutron flux level conversion section is configured to perform the conversion for the selected time range. Preferably, the analog signal processing device comprises: - an AC amplification section which amplifies the AC component of an output of a preamplifier which amplifies the output of the neutron detector and - an analog filter which eliminates A component of the high frequency region of a signal of the AC amplifier Preferably, the digitizer comprises a low pass filter which performs low pass filtering of the digital signal in time series and a cross section of the signal. resampling which resamples the digital signal in time series with a period greater than a sampling period of the digital signal in time series. According to one embodiment, a neutron flux level measuring device is provided, comprising: a neutron detector which detects neutrons produced by a nuclear reaction; and a neutron flux level calculating device which calculates a neutron flux level based on a signal of the neutron detector, the apparatus comprising: an analog signal processing device which amplifies an AC component of a neutron flux signal; detector output from a neutron detector and performs filtering to remove a high frequency component; a digitizing device which converts, 3021756 with a certain sampling period, an output signal of the analog signal processing device into a digital time-series signal; a wavelet analysis device which performs the discrete wavelet transformation using the time series digital signal to compute a wavelet coefficient; and a digital signal processing device which calculates a mean squared value of the wavelet coefficients and converts the calculated squared value into a neutron flux level value. According to one embodiment, a neutron flux level measurement method is provided comprising: an analog signal processing step fo for amplifying an AC component of a detector output signal from a neutron detector and implementing low pass filtering of a high frequency component; a digitizing step for digitizing, with a certain sampling period and in a time series manner, the detector output signal which has been subjected to low-pass filtering; a wavelet transform step for performing a discrete wavelet transform on the wavelet coefficient digitized detection output signal; and a level value conversion step for calculating a mean squared value of selected wavelet coefficients from the wavelet coefficients obtained by the discrete wavelet transform and converting the computed average squared value to a value of neutron flux level. Now, embodiments of a neutron flux level measuring device, a neutron flux level calculator and a neutron flux level measurement method will be described with reference to the drawings. attached. In all the drawings, the same components or similar components will be designated by the same reference symbols and will not be described in a repetitive manner. As a first embodiment, the present embodiment relates to a neutron flux level meter 100, a neutron flux level calculator 90, and a flux level measurement method. neutrons which target neutrons produced by nuclear reaction, such as neutrons produced by nuclear fission in a reactor core or neutrons produced in a fusion reactor. Fig. 1 is a block diagram showing a configuration of a neutron flux level measuring device according to a first embodiment. A neutron flux level meter 100 includes a neutron detection device 1 and a neutron flux level calculator 90. The neutron detection device 1 is a component that detects neutrons and produces a detection signal. corresponding and comprises a neutron detector 2 and a preamplifier 3. The neutron detector 2 is, for example, a fission chamber. A start range control detector can be used in the case of a boiling water reactor. The preamplifier 3 amplifies a weak signal of the neutron detector 2. The neutron flux level calculator 90 comprises an analog signal processing device 10, a digitizer 20, a wavelet analyzer 30, and a digital signal processing device 40. The analog signal processing device 10 comprises an AC amplifier 11 and an analog filter 12. The AC amplifier 11 extracts a statistical fluctuation component, i.e. say, an alternating signal component from an output signal of the preamplifier 3 and amplifies it. More specifically, the AC amplifier 11 uses a capacitor coupling arrangement to allow only the passage of the AC component and then amplifies it. The analog filter 12 eliminates a high frequency component of frequency greater than or equal to one frequency (Nyquist frequency) equal to half the sampling frequency of the analog / digital converter 21 which will be described later from a output signal corresponding to the AC signal component amplified by the AC amplifier 11. This prevents the generation of false echoes by sampling. The filtering 30 may be implemented using a low-pass filter or the like. The digitizer 20 comprises an analog / digital converter 3021756 21 and a first memory 22. The analog filter 12 filters and removes the high frequency component from its input. The analog / digital converter 21 scans, at a predetermined sampling period, the output signal of the analog filter 12. In addition, the first memory 22 stores a digital signal obtained as a result of the digitization. The sampling period is smaller than a period that can cover the statistical fluctuation component. However, the sampling period is not excessively lower in terms of computing load, which will be described later.
    [0005] The wavelet analysis device 30 includes a wavelet transformation section 31 and a second memory 32. The wavelet transformation section 31 applies a wavelet transformation to a time domain signal that has been digitized by the digitizer 20 in a wavelet coefficient. The wavelet transformation is described as shown in "Ten Lectures on Wavelets." I. Daubechies, SIAM, Philadelphia, 1992. An orthonormal basis, i.e., a function that can reproduce an original time domain signal by inverse transformation, is used as the mother wave of each level in the wavelet transformation. The second memory 32 stores the wavelet coefficient calculated by the wavelet transformation section 31. The digital signal processing device 40 has a coefficient selection / extraction section 41, a mean squared value calculation section 42, and a neutron flux level conversion section 43. The coefficient selection / extraction section 41 selects and extracts a necessary wavelet coefficient from a result of the calculation performed by the wavelet transformation section 31 That is, the coefficient selection / extraction section 41 performs selection / retrieval on the basis of frequency information, selection / retrieval on the basis of time information, and elimination of noise component. The RMS calculation section 42 calculates an average squared value of the wavelet coefficients selected and extracted by the coefficient selection / extraction section 41. The mean squared value corresponds to a neutron flux level, such as a fluctuation component of the output of the neutron detector 2 in a time domain. The neutron flux conversion section 43 converts the average squared value calculated by the mean squared value calculation section 42 into the neutron flux level. FIG. 2 is an algorithm representing a procedure for implementing the neutron flux level measurement method according to the first embodiment. First, neutrons are detected (step S01). When the neutrons strike the neutron detector 2, the neutron detector 2 generates a pulse-like detector output signal. As the number of neutrons striking the neutron detector 2 increases, the pulse-like detector output signals overlap each other, and it becomes impossible to discriminate the individual pulse-shaped signals. However, the statistical fluctuation of the output signal of the neutron detector 2 retains a relative relationship with the number of neutrons incident on the neutron detector 2, i.e., the neutron flux level or an on-board reactor power. a reactor base).
    [0006] The output signal having the statistical fluctuation is of low level and is thus amplified by the preamplifier 3. The signal amplified by the preamplifier 3 has a statistical fluctuation similar to the statistical fluctuation of the detector output signal. Next, the analog processing of the output signal of the neutron detecting device 1 is carried out (step S02). That is, the AC amplifier 11 extracts the random fluctuation component, i.e., the AC signal component from the output signal of the preamplifier 3 of the sensing device. neutron 1 and amplifies it. In addition, the analog filter 12 removes, from the output signal corresponding to the amplified AC signal component amplified by the amplifier 11, a high frequency component greater than or equal to one frequency (frequency of 3021756 -10- Nyquist). equal to half the sampling frequency of the analog / digital converter 21 in the next step. Then, the detector output signal that has been subjected to analog processing in step SO2 is digitized (step S03). That is, the analog-to-digital converter 21 digitizes, at the predetermined sampling period mentioned above, the output signal of the analog filter 13. The first memory 22 sequentially stores the digital signal. Next, the wavelet analyzer 30 applies a DWT (Discrete Wavelet Transform) transformation to the digitized time domain signal at step S03 (step SO4). That is, the wavelet transformation section 31 applies the DWT transformation to the time domain signal to transform the time domain signal into a wavelet coefficient, i.e., to calculate the wavelet coefficient. More specifically, a number of the time domain digital signals are read from the first memory 22 and subjected to the DWT transformation. The wavelet transformation section 31 provides the same number of wavelet coefficients as the number of digital signals used in the DWT transformation. The wavelet coefficients obtained are stored in the second memory 32.
    [0007] Assuming that 2N digital time-series signals sampled at a sub-sampling sampling period AT are produced. In this case, a level 1 mother wavelet is a function of a 2AT period. The level 1 mother wavelet is used to perform the DWT 2N-1 transformation, so that 2N-1 wavelet coefficients are obtained.
    [0008] Similarly, a level 2 parent wavelet is a function having the same form as the function of the level 1 mother wavelet and having a 22AT period. By using the mother wavelet of level 2, 2N-2 wavelet coefficients are obtained. A last level N- mother wavelet is a function having the same form as the function of the level 1 mother wavelet having a period of 2NAT. Using the N-level mother wavelet, a first wavelet coefficient is obtained. In this way, a total of 2N wavelet coefficients, i.e., the same number of wavelet coefficients as the number of digital signals, are obtained. Next, the coefficient selection / extraction section 41 of the digital signal processor 40 selects a necessary wavelet coefficient from the wavelet coefficients calculated in step SO4. The selection and the extraction are carried out both from the time domain and the frequency domain (step S05). The wavelet coefficient transformed signal by the wavelet transformation section 31 includes both time axis information and frequency axis information indicating, for example, that there is a 100 kHz signal component. about up to several hundred kHz approximately on the data at a certain time or a noise component at about 1 MHz. Therefore, the selection and extraction (filtering) of the necessary signal is carried out on the basis of time and frequency information to thereby eliminate a noise component. Fig. 3 is a graph showing an example of a time change of the output signal of the neutron detector. A horizontal axis indicates a time, and a vertical axis indicates a value of the output signal of the neutron detection device 1. At a time T 1, a large noise is superimposed on the output signal. A result obtained by applying the wavelet transformation to the output signal will be described below. Fig. 4 is a graph showing a result of the wavelet transformation. Fig. 5 is a graph showing a result of the wavelet transformation in a case in which bandwidth is limited. Fig. 6 is a graph showing a result of wavelet transformation in a case in which bandwidth limitation and noise elimination are performed. The graphs of FIGS. 4 to 6 each represent a three-dimensional graph, in which one of the horizontal axes indicates a time, and the other of these, perpendicular to the time axis, indicates a level obtained by the intermediate of the wavelet transformation. A vertical axis indicates a value of the wavelet coefficient of each level obtained through the wavelet transformation. FIG. 4 shows a result obtained by applying the wavelet transformation on the output signal from the neutron detection device 1. With the exception of certain time zones, a peak appears in a range in which the level of output signal is the highest. The graph also shows a peak corresponding to the noise produced at time T1. On this graph, the ridge has a mountain-like shape, which, however, does not mean that the peak values are a continuous mountain form, but is a result simply obtained by connecting respective level values on the graph.
    [0009] Fig. 5 shows a result of the wavelet transformation in a case in which a bandwidth is limited, i.e., in which a bandwidth in the frequency domain is limited, in which a peak to high level, that is, a long period ridge has disappeared. Fig. 6 shows a result of the wavelet transformation in a case in which bandwidth limitation and noise elimination are implemented, i.e., a result obtained by eliminating data around of the instant Ti at which the noise occurs. Thus, as shown in FIG. 5, a wavelet coefficient value corresponding to the fluctuation having a relative relationship with the neutron flux level is obtained.
    [0010] Then, as shown in Fig. 2, the digital signal processing device 40 calculates the mean square value to thereby calculate the neutron flux level (step S06). That is, the RMS calculation section 42 calculates the rms value of the selected wavelet coefficients, i.e., a value obtained by dividing the sum of the squares by the number of data. Thus, the neutron flux level conversion section 43 converts the output signal of the RMS calculation section 42 into a neutron measurement value. As previously described, the neutron flux conversion section 43 performs a processing on the rms value to correct the attenuation effect thereon due to the presence of a filter 3021756. 13 - low-pass to ensure the sampling implemented in the analog-to-digital converter 21 and the limitation of bandwidth and noise reduction by the coefficient selection / extraction section 41, and furthermore to correct the sensitivity of the neutron detector 2, so that a neutron level signal can be obtained. In addition, as the fluctuation component of the output of the neutron detector 2 in the time domain, the mean squared value of the wavelet coefficients corresponds to the neutron flux level, thus eliminating the need to perform an inverse transformation (DWT transformation reverse) of the DWT transformation. For example, a gate array element (programmable logic device (PLD), or an in-situ programmable gate array (FPGA), or the like) for performing a calculation in a wired logic circuit has computational capability. This logic may be weaker compared to that of a microprocessor (MPU) or a digital processing unit (DSP) which executes the calculation by means of a program. Thus, it is relatively difficult to implement both the DWT transformation and the inverse DWT transformation. However, the present embodiment eliminates the need for the implementation of the inverse DWT transformation, which improves the ease of implementation. In the neutron measurement method in a conventional neutron measuring device, the time domain detector output signal is detected, and is subjected to the analysis calculation processing to provide control. When the frequency component of the neutron signal to be measured covers the frequency component of a noise signal, it is difficult to avoid influences of noise. On the other hand, according to the present embodiment, even in a state in which the frequency component of the neutron signal covers the frequency component of the noise signal, when the noise is not stationary, i.e. when an instant at which the noise is superimposed on the neutron signal can be specified, it is possible to discriminate the wavelet coefficient at a time when the noise is superimposed on the neutron signal, and eliminate the noise in the time domain, thus enabling the neutron measurement value to be obtained rapidly in which influences of the noise signal are eliminated. As previously described, according to the present embodiment, it is possible to rapidly implement a measurement of the neutron flux level while eliminating the influences of noise. A second embodiment will next be described below. Fig. 7 is a block diagram showing a configuration of the neutron flux meter according to a second embodiment. The second embodiment is a variant of the first embodiment. A digitizer 20a of the neutron flux level calculator 90 according to the second embodiment further comprises a low pass filter 27, a low pass filter 27a, a resampling section 28, a cross section resampling 28a, a level number selection section 33, and a selection range switching section 44, in addition to the analog / digital converter 21 and the first memory 22. The resampling section 28 and the resampling section 28a can resample the data sampled by the analog-to-digital converter 21 to their respective sampling frequencies lower than the sampling frequency of the analog-to-digital converter 21. The low-pass filter 27 eliminates a frequency component of frequency greater than or equal to 1/2 of the re-sampling frequency of the resampling section 28. In addition, the low-pass filter 27a eliminates a frequency component of frequency greater than or equal to 1/2 of the resampling frequency of the resampling section 28a. The level number selection section 33 can modifyably select the number of DWT transformation levels. The selection range switching section 44 adjusts a correspondence change between a signal after the DWT transformation and a frequency range of the neutron signal when the resampling frequency is changed or when the selection section 3021756 - 15 - 33-level count modifies the number of DWT transformation levels. According to the present embodiment, when the neutron signals in the same time range are measured, resampling is performed at a sampling frequency lower than the sampling frequency of the analog-to-digital converter 21. This allows the application of the DWT transformation to a lower number of levels, improving the possibility of implementing the neutron flux level calculator 90. In addition, by making the resampling frequency selected, a time range for which the DWT transformation is implemented is made variable in a case in which the DWT transformation using the same number of data is implemented. This means that the standard deviation, due to the statistical fluctuations of the neutron-measured signal or to the reactivity to a change of neutron signal, can be selected.
    [0011] Furthermore, in the frequency domain, it is possible to make a frequency range to be measured can be selected by changing the sampling frequency and the number of wavelet transformation levels, thus making it possible to adjust a range. of appropriate frequency as a function of a frequency of the neutron signal to be measured. That is, when a rapid change of the neutron signal is measured, an upper limit of the frequency to be measured can be increased by setting the sampling frequency to a higher value; on the other hand, when a slow variation of the neutron signal is measured, an upper limit of the frequency to be measured can be reduced by setting the sampling frequency to a lower value. In addition, it is possible to extend a frequency range to be measured by increasing the number of wavelet transformation levels; on the other hand, it is possible to reduce a frequency range to be measured by reducing the number of wavelet transformation levels. A third embodiment will then be described below.
    [0012] Fig. 8 is a block diagram showing a configuration of the neutron flux level meter according to a third embodiment. The third embodiment is a variant of the first embodiment. A digital signal processing device 40a of the neutron flux level calculator 90 according to the third embodiment further comprises a time coefficient selection section 45 added to the coefficient selection / extraction section. 41, at the mean squared value calculation section 42, and at the neutron flux level conversion section 43. The time coefficient selection section 45 selects wavelet coefficients corresponding to a certain time range and outputs the coefficients. wavelets selected at the mean squared value calculation section 42. In the present embodiment, when the DWT transformation is implemented for time axis data corresponding to a long duration, the coefficient selection section time 45 selects some of the wavelet coefficients after the DWT transformation as a function of the reactivity 15 e and t of the measurement accuracy required for the neutron flux level meter 100. As previously described, it is possible to change a time width to be selected after the DWT transformation using a fact that the DWT transformation retains the temporal information, thus making it possible to adjust the accuracy and responsiveness of the neutron measurement without changing the DWT transformation logic itself. A fourth embodiment will then be described below. Fig. 9 is a block diagram showing a configuration of the neutron flux level measuring device according to a fourth embodiment. The fourth embodiment is a variant of the first embodiment. A digital signal processing device 40b of the neutron flux level calculator 90 according to the fourth embodiment further includes a responsiveness selection section 46, a third memory 47, and an addition / calculation section. averaging 48 in addition to the coefficient selection / extraction section 41, the mean squared value calculation section 42, and the neutron flux level conversion section 43. 3021756 - 17 - The selection section Reactivity 46 can select the accuracy, standard deviation, or responsiveness of the neutron flux level measurement result. The third memory 47 stores the average squared value calculated by the mean squared value calculation section 42. The averaging / averaging section 48 adds and averages a plurality of the mean squared values. The number of mean squared values to be added, the average of which must be calculated by the addition / averaging section 48, is variable depending on the accuracy, standard deviation or responsiveness selected by the selection section. responsiveness 46.
    [0013] According to the present embodiment, it is possible to obtain a value equivalent to the mean square value obtained by simple DWT transformation implemented collectively for data corresponding to a longer duration. That is, by adding and calculating the average of the plurality of RMS values obtained through the DWT transformation implemented for a smaller number of data corresponding to a shorter duration, it is possible to obtain a mean squared value that is initially obtained by implementing the DWT transformation for a larger number of data corresponding to a longer duration. This makes it possible to reduce a necessary capacity of the DWT transformation logic part, thus improving the ease of implementation. By measuring the neutron signal for a longer time while shortening the execution time of the DWT transformation to improve the responsiveness of the neutron signal control, the measurement accuracy can be improved. In addition, by making the number of mean squared values to be added and the average of which is to be calculated variable, the accuracy or reactivity of the neutron signal measurement can be selected. Fig. 10 is a block diagram showing a configuration of a variant of the neutron flux level measuring device according to the fourth embodiment. The present embodiment is a variation of the first embodiment. A digital signal processing device 40c according to this variant has the responsiveness selection section 46, a third memory 47, and an addition / averaging section 48 as for the fourth embodiment but differs from the fourth embodiment by the transmission and reception relation of input and output data. That is, in addition to the coefficient selection / extraction section 41, the mean squared value calculation section 42, and the neutron flux level conversion section 43 of the first embodiment. the third memory 47 stores a conversion result of the neutron flux level conversion section 43. The addition / averaging section 48 adds and averages the coefficients extracted from the third memory 47. At this time , the reactivity selection section 46 which can select the accuracy, standard deviation, or reactivity of the neutron flux level measurement result adjusts a calculation range of the addition / averaging section 48. In this variant, the same effects as those obtained with the fourth embodiment can be obtained. A fifth embodiment will then be described below. Fig. 11 is a block diagram showing a configuration of the neutron flux level measuring device according to a fifth embodiment. The present embodiment is a variation of the first embodiment. A digital signal processing device 40d of the neutron flux level calculator 90 according to the fifth embodiment further includes a third memory 47, an inverse wavelet transformation section 50, a fourth memory 51, and a RMS calculation section 52 in addition to the section at the coefficient selection / extraction section 41 and the neutron flux level conversion section 43. The inverse wavelet transformation section 50 extracts, from the third memory 47, the wavelet coefficient selected by the coefficient selection / extraction section 41 and applies the inverse wavelet transformation (inverse DWT transformation). Application of the inverse DWT transformation transforms the time domain / frequency data into time domain data. The fourth memory 51 stores a result of the inverse DWT transformation. The root mean square calculating section 52 extracts the time domain data from the fourth memory 51 and calculates a root mean square of the time domain data. In the neutron flux level calculator 90 according to the present embodiment, the wavelet analysis device 30 implements the DWT transformation, and the coefficient selection / extraction section 41 of the signal processing device. Digital 40d performs filtering in the time and frequency domains to thereby eliminate a noise component. Then, the inverse DWT transformation is implemented by inverse transforming the time domain / frequency data into time domain data. The results are squared and the calculated average, and the resulting value is converted to a neutron flux level value by the neutron flux level conversion section 43. As previously described, also by implementing the In the inverse DWT transformation, it is possible to obtain a neutron measurement value in which a noise component is eliminated while preventing mixing of a noise signal, so that the neutron flux level can be measured with precision. A sixth embodiment will then be described below.
    [0014] Fig. 12 is a block diagram showing a configuration of the neutron flux meter according to a sixth embodiment. The present embodiment is a variant of the first embodiment. A digital signal processing device 40e of the neutron flux level calculator 90 according to the sixth embodiment 25 further comprises an abnormality determination section 53 and a complementary mean square value calculation section 54. The abnormality determination section 53 determines whether or not any of the wavelet coefficients obtained by the wavelet analysis device 30 has an abnormal value due to the influences of a noise signal.
    [0015] When the abnormality determination section 53 determines that any of the wavelet coefficients obtained by the wavelet analysis device has an abnormal value, the complementary mean squared value calculation section 54 calculates a mean squared value by interpolation or extrapolation using a prior mean squared value obtained by the mean squared value calculation section 42 to form the complement of the wavelet coefficient. The complementary value can be obtained by using a mean squared value obtained, for example, in a previous calculation before the previous calculation by the mean squared value calculation section 42. In the present embodiment, the presence / absence of the An anomaly of the wavelet coefficient is determined, and when the anomaly is present, a normal mean squared value calculation is not performed, but a complementary value is obtained based, for example, on the previous mean squared value. or next. This eliminates the need to perform wavelet coefficient selection / extraction, thereby eliminating the need to implement a calculation logic for selection and extraction. Thus, it is possible to quickly measure the neutron flux level while eliminating the influence of noise. Other embodiments are possible. Although the present invention has been described above by means of several embodiments, the embodiments described above are presented solely by way of examples without any intention to limit the scope of the present invention. Any of the characteristic features of two or more of the embodiments described above may be associated for use. In addition, the embodiments described above can be modified in different ways. For example, any of the components of the embodiments may be omitted, replaced, or modified without departing from the scope of the invention.
    [0016] All of these embodiments and their variants are within the scope of the present invention specifically defined above as well as their
    权利要求:
    Claims (9)
    [0001]
    REVENDICATIONS1. A neutron flux level calculating apparatus comprising: an analog signal processing device which amplifies an AC component of a detector output signal from a neutron detector and performs filtering for removing a high frequency component; a digitizing device which converts, with a certain sampling period, an output signal of the analog signal processing device into a digital time-series signal; a wavelet analysis device that performs a discrete wavelet transform using the time series digital signal to compute a wavelet coefficient; and a digital signal processing device which calculates a mean squared value of the wavelet coefficients and converts the calculated squared value into a neutron flux level value.
    [0002]
    A neutron flux level calculating apparatus according to claim 1, wherein the wavelet analysis device comprises the wavelet transform section which applies the discrete wavelet transform on the digital signal in time series using an orthonormal base in order to calculate the same number of onlelette coefficients as the number of digital signals in time series.
    [0003]
    The neutron flux level calculating apparatus according to claim 1 or 2, wherein the digital signal processing device comprises: a coefficient selection / extraction section which selects from a result of the calculation executed by the wavelet analysis device, the wavelet coefficient having a necessary frequency component; a quadratic mean calculating section which calculates the average quadratic value of the coefficient selected by the coefficient selection / extraction section; and a neutron flux level conversion section which converts the rms value into a neutron flux level value. 5
    [0004]
    The neutron flux level calculating apparatus according to claim 3, wherein the coefficient selection / extraction section is configured to selectively select a frequency range, and the neutron flux level conversion section is configured to perform the conversion for the selected frequency range.
    [0005]
    A neutron flux level calculator according to claim 3 or 4, wherein the coefficient selection / extraction section is configured to changably select a time range, and the flux level conversion section. Neutron is configured to perform the conversion for the selected time range.
    [0006]
    The neutron flux level calculating device according to any one of claims 1 to 5, wherein the analog signal processing device comprises: an AC amplification section which amplifies the AC component of an output a preamplifier that amplifies the output of the neutron detector; and an analog filter that removes a component of the high frequency area of a signal from the AC amplifier. 25
    [0007]
    A neutron flux level calculating apparatus according to any one of claims 1 to 6, wherein the digitizing device comprises: a low pass filter which low pass filtering of the digital signal in time series; and a resampling section that resamples the digital signal in time series with a period greater than a sampling period of the digital signal in time series.
    [0008]
    A neutron flux level measuring device, comprising: a neutron detector which detects neutrons produced by a nuclear reaction; and a neutron flux level calculating device which calculates a neutron flux level based on a signal from the neutron detector, the device having an analog signal processing device which amplifies an AC component of a signal detector output from a neutron detector and performs filtering to remove a high frequency component; a digitizing device which converts, with a certain sampling period, an output signal of the analog signal processing device into a digital time-series signal; A wavelet analysis device which performs the discrete wavelet transform using the time series digital signal to compute a wavelet coefficient; and a digital signal processing device which calculates a mean square value of the wavelet coefficients and converts the computed average squared value into a neutron flux level value.
    [0009]
    A method of neutron flux level measurement comprising: an analog signal processing step for amplifying an AC component of a detector output signal from a neutron detector and for performing low pass filtering a high frequency component; a digitizing step for digitizing, with a certain sampling period and in a time series manner, the detector output signal which has been subjected to low-pass filtering; a wavelet transform step for performing a discrete wavelet transform on the wavelet coefficient digitized detection output signal; and a step of level value conversion for calculating an average squared value of selected wavelet coefficients from the wavelet coefficients obtained by the discrete wavelet transform and converting the calculated squared value to a neutron flux level value.
    类似技术:
    公开号 | 公开日 | 专利标题
    FR3021756A1|2015-12-04|NEUTRON FLUX LEVEL MEASUREMENT SYSTEM, NEUTRON FLUX LEVEL CALCULATOR, AND NEUTRON FLUX LEVEL MEASUREMENT METHOD
    FR2987454A1|2013-08-30|NEUTRON MEASURING APPARATUS AND NEUTRON MEASURING METHOD
    EP2484011B1|2013-08-07|Device for the processing of a signal generated by a radiation detector
    EP2788831B1|2019-01-09|Method and device for detecting electric arc in a photovoltaic installation
    EP0562021B1|1995-11-08|Method of recognizing a ventricular cardiac pathological condition for automatic defribillation purposes
    EP3187842B1|2018-09-05|Method for detecting an electric arc by analysing the acoustic signature thereof
    EP0813282B1|2003-12-10|Ground fault detection apparatus for a device connected to a power distribution or transmission network, and corresponding method
    EP3631517B1|2021-03-31|Method and device for processing neutron flux signals, associated computer program product and control system
    FR3030780A1|2016-06-24|
    EP2959303A1|2015-12-30|Method and device for detecting an electric arc in a photovoltaic installation
    EP1940023A2|2008-07-02|Bank of cascadable digital filters, and reception circuit including such a bank of cascaded filters
    FR3016758A1|2015-07-24|METHOD AND SYSTEM FOR DYNAMIC EXTRACTION OF PULSES IN A NAKED TIME SIGNAL
    FR2879305A1|2006-06-16|PROCESSING A REPRESENTATIVE RADIATION SIGNAL
    EP3157181B1|2017-12-27|Ultra wideband signal detection
    EP3232212A1|2017-10-18|System and method for detecting an electric arc
    EP2491412B1|2016-03-16|Method for detecting a wavefront corresponding to an event in a signal received by a detector
    FR3054339A1|2018-01-26|CORRECTION METHOD WITHOUT CALIBRATING A DEFECT INTRODUCED BY A SCANNING SYSTEM AND ASSOCIATED DEVICES
    EP2656531B1|2019-05-01|Impulse noise measurement by spectral detection
    El_Tokhy et al.2010|Comparative analysis between different linear filtering algorithms of gamma ray spectroscopy
    EP0661555B1|1999-02-03|Detection and discrimination device for radar impulses
    FR3090130A1|2020-06-19|Determination of the evolution of an underwater environment by acoustic analysis
    Wang et al.2004|A novel nonuniform sampling method and processing system to overcome the Nyquist limit and suppress the noise
    EP1010985A1|2000-06-21|Method of determining the level of harmonic distortions of an electrical network and device with it
    FR2885758A1|2006-11-17|Multi-mode acquisition and processing system for nuclear reactor signals has module triggering authorisation of digital signals pertaining to events
    FR3054338A1|2018-01-26|METHOD OF CORRECTING DEFECTS INTRODUCED BY A SCANNING SYSTEM AND ASSOCIATED DEVICES
    同族专利:
    公开号 | 公开日
    US20150348656A1|2015-12-03|
    FR3021756B1|2018-08-10|
    JP2015224970A|2015-12-14|
    JP6334264B2|2018-05-30|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    CN101078775A|2007-06-29|2007-11-28|西安奥华电子仪器有限责任公司|Impulse neutron bispectrum saturation logging method|
    US8412468B1|2009-04-08|2013-04-02|Western Kentucky University|Method and apparatus for wavelet based elemental spectrum analysis|
    FR2987454A1|2012-02-29|2013-08-30|Toshiba Kk|NEUTRON MEASURING APPARATUS AND NEUTRON MEASURING METHOD|
    JP3358988B2|1998-04-28|2002-12-24|三菱重工業株式会社|Signal processing device|
    CN103218512A|2013-03-14|2013-07-24|西安交通大学|Method for acquiring neutron angular flux density in nuclear fuel assembly|FR3038989B1|2015-07-16|2021-09-24|Toshiba Kk|NEUTRON MEASURING APPARATUS, NEUTRON CALCULATION APPARATUS, AND NEUTRON MEASUREMENT METHOD|
    RU2650810C1|2017-03-27|2018-04-17|Российская Федерация, от имени которой выступает Государственная корпорация по атомной энергии "Росатом" |Device for determination of research nuclear installation fields neutron characteristics|
    RU2729600C1|2019-12-27|2020-08-11|Федеральное государственное унитарное предприятие "Предприятие по обращению с радиоактивными отходами "РосРАО"|Method of diagnosing stability of operation of a device with a corona counter for measuring neutron flux in the presence of gamma-radiation|
    CN111640519A|2020-05-07|2020-09-08|中国工程物理研究院核物理与化学研究所|Reactor neutron noise spectrum analysis method based on improved wavelet fractal algorithm|
    法律状态:
    2016-01-21| PLFP| Fee payment|Year of fee payment: 2 |
    2017-02-03| PLFP| Fee payment|Year of fee payment: 3 |
    2017-12-29| PLSC| Publication of the preliminary search report|Effective date: 20171229 |
    2018-01-22| PLFP| Fee payment|Year of fee payment: 4 |
    2020-01-13| PLFP| Fee payment|Year of fee payment: 6 |
    2021-01-12| PLFP| Fee payment|Year of fee payment: 7 |
    2022-01-18| PLFP| Fee payment|Year of fee payment: 8 |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2014110141|2014-05-28|
    JP2014110141A|JP6334264B2|2014-05-28|2014-05-28|Neutron flux level measuring device, neutron flux level computing device, and neutron flux level measuring method|
    [返回顶部]