JP2021004856A - Spectroscopic analysis device and spectroscopic analysis method - Google Patents

Abstract

To appropriately analyze a solid component in a solution, while suppressing decline in analysis accuracy of a radioactive substance in the solution.SOLUTION: A spectroscopic analysis device comprises: a light source unit that irradiates a solution X containing a radioactive substance and a solid matter other than the radioactive substance with light; a detection unit that detects the light transmitting the solution; and a computation unit 15. The computation unit 15 includes: an absorbance spectrum calculation unit 32 that calculates an absorbance spectrum of the solution from the light the detection unit detects; a baseline calculation unit 34 that calculates a baseline from the absorbance spectrum; a radioactive analysis unit 36 that calculates density of the radioactive substance on the basis of a modified spectrum obtained by subtracting the baseline from the absorbance spectrum; and a solid matter analysis unit 38 that calculates an amount of the solid matter on the basis of the baseline.SELECTED DRAWING: Figure 3

Description

The present invention relates to a spectroscopic analyzer and a spectroscopic analysis method.

A spectrophotometer may be used to analyze the radioactive material in the solution. In this case, the concentration of the radioactive substance is calculated from the absorbance spectrum showing the absorbance of the light by the solution for each wavelength. For example, Patent Document 1 describes that the laser beam is separated to measure the uranium concentration in the solution.

JP-A-2008-249328

However, the absorbance spectrum may be deformed at the baseline due to solid components other than the measurement target (radioactive substance) contained in the solution. If the baseline is deformed in this way, the accuracy of analysis of radioactive substances may decrease. Further, for example, in order to monitor the process of solution treatment, it is required to analyze the solid components in such a solution.

The present invention solves the above-mentioned problems, and provides a spectroscopic analyzer and a spectroscopic analysis method capable of appropriately analyzing solid components in a solution while suppressing a decrease in analysis accuracy of radioactive substances in the solution. The purpose is.

In order to solve the above-mentioned problems and achieve the object, the spectroscopic analyzer according to the present disclosure uses a light source unit that irradiates a solution containing a radioactive substance and a solid substance other than the radioactive substance with light, and the solution. A detection unit that detects transmitted light and a calculation unit are provided, and the calculation unit is based on an absorbance spectrum calculation unit that calculates the absorbance spectrum of the solution from the light detected by the detection unit and the absorbance spectrum. A baseline calculation unit for calculating the line, a radioactive substance analysis unit for calculating the concentration of the radioactive substance based on the corrected spectrum obtained by subtracting the baseline from the absorbance spectrum, and an amount of the solid substance based on the baseline. It is provided with a solid matter analysis unit for calculating.

According to this spectroanalyzer, the concentration of radioactive substances is calculated based on the corrected spectrum obtained by subtracting the baseline from the absorbance spectrum, so that the influence of solid substances can be removed from the spectrum, and the accuracy of calculating the concentration of radioactive substances is reduced. Can be suppressed. In addition, the spectroscopic analyzer can appropriately analyze the solid components in the solution by calculating the amount of the solid matter based on the baseline.

When the baseline is set to Y = a · X + b, the baseline calculation unit can calculate the baseline by calculating the slope a and the constant b of the baseline from the absorbance spectrum. preferable. Here, X is the wavelength of the light in the absorbance spectrum, and Y is the absorbance in the absorbance spectrum. By treating the baseline as a straight line, the spectroscopic analyzer can calculate the baseline with high accuracy, and can appropriately analyze solids while suppressing a decrease in the analysis accuracy of radioactive substances. ..

It is preferable that the baseline calculation unit calculates the gradient a based on the absorbance of the absorbance spectrum at a wavelength for calculation, which is a wavelength other than a certain wavelength at which the peak due to absorption of the radioactive substance in the absorbance spectrum is present. Since the spectroscopic analyzer calculates the slope a based on the absorbance at the calculation wavelength, it is possible to calculate the baseline with high accuracy, and it is appropriate to analyze solids while suppressing a decrease in the analysis accuracy of radioactive substances. Can be done.

It is preferable that the baseline calculation unit calculates the first derivative value of the absorbance of the absorbance spectrum at the calculation wavelength, and calculates the slope a based on the first derivative value. Since the spectroscopic analyzer calculates the slope a from the first derivative of the absorbance at the calculation wavelength, it is possible to calculate the baseline with high accuracy, and while suppressing the decrease in the analysis accuracy of radioactive substances, solid matter The analysis can be performed appropriately.

It is preferable that the baseline calculation unit calculates the first derivative value for the plurality of the calculation wavelengths, and calculates the slope a from the average value of the plurality of the first derivative values. Since the spectroscopic analyzer calculates the slope a from the average value of a plurality of first derivative values, it is possible to calculate the baseline with high accuracy, and it is possible to analyze solids while suppressing a decrease in the analysis accuracy of radioactive substances. Can be done properly.

The solid matter analysis unit preferably calculates the amount of the solid matter for each particle size based on the baseline. Since the spectroscopic analyzer calculates the amount of the solid matter contained in the solution for each particle size of the solid matter, the analysis of the solid matter can be appropriately performed.

The solid matter analysis unit calculates the amount of the solid matter having a first particle size based on the constant b, and based on the slope a, the solid matter having a second particle size smaller than the first particle size. It is preferable to calculate the amount of things. Since the spectroscopic analyzer calculates the amount of the solid matter contained in the solution for each particle size of the solid matter, the analysis of the solid matter can be appropriately performed.

The radioactive substance is preferably at least one of uranium and plutonium. The spectroscopic analyzer can suppress a decrease in the calculation accuracy of the concentrations of uranium and plutonium.

In order to solve the above-mentioned problems and achieve the object, the spectroscopic analysis method according to the present disclosure comprises an irradiation step of irradiating a solution containing a radioactive substance and a solid substance other than the radioactive substance with light, and the solution. The calculation step includes a detection step for detecting transmitted light and a calculation step, and the calculation step is based on the absorbance spectrum calculation step for calculating the absorbance spectrum of the solution from the light detected in the detection step and the absorbance spectrum. A baseline calculation step for calculating the line, a radioactive substance analysis step for calculating the concentration of the radioactive substance based on the corrected spectrum obtained by subtracting the baseline from the absorbance spectrum, and an amount of the solid substance based on the baseline. Includes a solids analysis step to calculate. According to this spectroscopic analysis method, it is possible to appropriately analyze solid substances while suppressing a decrease in analysis accuracy of radioactive substances.

According to the present invention, it is possible to appropriately analyze solid components in a solution while suppressing a decrease in analysis accuracy of radioactive substances in the solution.

FIG. 1 is a schematic view of a spectroscopic analyzer according to the present embodiment. FIG. 2 is a partially enlarged view showing an example of the measurement probe according to the present embodiment. FIG. 3 is a schematic block diagram of the calculation unit according to the present embodiment. FIG. 4 is a graph showing an example of the absorbance spectrum. FIG. 5 is a graph showing an example of the modified spectrum. FIG. 6 is a graph of an example for explaining scattering by a solid substance. FIG. 7 is a graph of an example for explaining scattering by a solid substance. FIG. 8 is a graph showing an example of a baseline. FIG. 9 is a flowchart illustrating a calculation flow of the concentration of the radioactive substance and the amount of the solid matter according to the present embodiment.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited to this embodiment, and when there are a plurality of embodiments, the present invention also includes a combination of the respective embodiments.

FIG. 1 is a schematic view of a spectroscopic analyzer according to the present embodiment. As shown in FIG. 1, the spectroscopic analyzer 1 according to the present embodiment is an apparatus for analyzing the solution X. The solution X is a fluid containing a radioactive substance X1 and a solid substance (SS; Suspended Solid) X2 having a component other than the radioactive substance X1. In the present embodiment, the solution X is produced by dissolving a fuel containing, for example, radioactive substance X1 in a solvent such as nitric acid. The solution X preferably contains a fluid whose components are known, in other words, it is preferable that the elements contained as the radioactive substance X1 and the solid substance X2 are known. In this embodiment, the radioactive material X1 is uranium and plutonium. Further, the solid substance X2 is a substance that is not a radioactive substance, and is preferably a substance that does not have a peak of absorbance by the measurement light L1 described later.

The solution X flows through the pipe 10 in a nuclear facility such as a nuclear fuel reprocessing plant. The solution X is a solution after a predetermined treatment (removal of solid matter in the present embodiment) has been performed by the processing unit F, which is a filter provided in the pipe 10. The spectroscopic analyzer 1 calculates the concentration (elemental concentration) of the radioactive substance X1 contained in the solution X and the amount of the solid substance X2 contained in the solution X. As a result, the spectroscopic analyzer 1 can check whether the radioactive substance X1 is properly managed, the processing by the processing unit F, and here the removal of the solid matter is properly performed. The processing unit F is not limited to being provided in the pipe 10, and may be provided at a position other than the pipe 10. Further, the processing unit F is not an indispensable configuration, and the processing unit F may not be provided. Further, the spectroscopic analyzer 1 is not limited to analyzing the solution X flowing through the pipe 10 online, and may analyze, for example, the solution X stored in the container.

The spectroscopic analyzer 1 includes a light source unit 12, a measurement probe 13, a detection unit 14, and a calculation unit 15. The spectroscopic analyzer 1 irradiates the measurement light L1 from the light source unit 12 into the pipe 10 through which the solution X flows, and detects the transmitted light L2 which is the measurement light L1 transmitted through the solution X by the detection unit 14. Then, the spectroscopic analyzer 1 calculates the absorbance spectrum of the solution X based on the transmitted light L2 detected by the detection unit 14 by the calculation unit 15, and includes the concentration of the radioactive substance X1 contained in the solution X and the concentration of the radioactive substance X1 contained in the solution X. The amount of the solid substance X2 to be obtained is calculated. The nuclear facility in the present embodiment is divided into a high-dose compartment AR1 having a high air dose rate and a low-dose compartment AR2 having a lower air dose rate than the high-dose compartment AR1 by the wall portion 18. The high-dose compartment AR1 is provided with a pipe 10 and a measurement probe 13 of the spectroscopic analyzer 1. The light source unit 12, the detection unit 14, and the calculation unit 15 of the spectroscopic analyzer 1 are provided in the low dose compartment AR2. The measurement probe 13 and the light source unit 12 are connected by an optical fiber cable 16 provided from the high-dose compartment AR1 to the low-dose compartment AR2. The measurement probe 13 and the detection unit 14 are connected by an optical fiber cable 17 provided from the high dose compartment AR1 to the low dose compartment AR2.

The light source unit 12 includes a light source that irradiates the measurement light L1 and a spectroscope that disperses the measurement light L1 from the light source to a desired wavelength. As the light source of the light source unit 12, an incandescent light bulb is used for the analysis of the visible light region, a tungsten lamp is used for the analysis of the visible light region to the near infrared region, and a heavy hydrogen discharge tube or the like is used for the analysis of the ultraviolet region. Is used. In the spectroscopic analyzer 1 according to the present embodiment, various light sources are switched and used according to the type of the element to be analyzed in the solution X. Among these, from the viewpoint of being able to analyze radioactive elements such as uranium and plutonium with high accuracy, the light source unit 12 is preferably one capable of detecting a near infrared region such as a tungsten lamp. Specifically, the light source unit 12 preferably disperses the measurement light L1 at a wavelength of 200 nm or more and 1100 nm or less, and more preferably disperses the measurement light L1 at a wavelength of 200 nm or more and 900 nm or less. .. In the present embodiment, in order to stabilize the baseline B described later, the wavelength range of the measurement light L1, in other words, the difference between the minimum wavelength and the maximum wavelength of the dispersed measurement light L1 is widely set. It is preferable to keep it.

The measurement probe 13 is connected to the light source unit 12 via the optical fiber cable 16. The light source unit 12 transmits the measurement light L1 having a wavelength corresponding to the component of the analysis target contained in the solution X to the measurement probe 13 via the optical fiber cable 16.

The measurement probe 13 is connected to the detection unit 14 via an optical fiber cable 17. One end of the optical fiber cable 17 is connected to the detection unit 14, the other end penetrates the flange 10a in the measurement probe 13, and is arranged inside the pipe 10 side. The measuring probe 13 receives the measurement light L1 transmitted from the light source unit 12 and irradiates the received measurement light L1 toward the solution X that has entered the flow path portion 13b. Further, the measurement probe 13 transmits the transmitted light L2 transmitted through the solution X in the flow path portion 13b via the optical fiber cable 17 toward the detection unit 14.

FIG. 2 is a partially enlarged view showing an example of the measurement probe according to the present embodiment. As shown in FIG. 2, the measuring probe 13 has a hollow shape, and has a tip portion 16a of the optical fiber cable 16 and an optical fiber cable 16 at a tip portion 13a away from the base end 13c fixed to the flange 10a of the measuring probe 13. The tip portion 17a of the fiber cable 17 is fixed. At the tip 16a of the optical fiber cable 16 and the tip 17a of the optical fiber cable 17, the measurement light L1 emitted from the optical fiber cable 16 and the transmitted light L2 received by the optical fiber cable 17 are in opposite directions. Have been placed. The measurement probe 13 according to the present embodiment is not limited to the structure described below, and includes a sampling line for sampling the solution X through the bypass, a distribution cell connected to the sampling line, and an irradiation device. It may be provided with an inlet for light and an outlet for transmitted light for measurement. In this case, the solution X supplied from the sampling line flows in the distribution cell. The straight line (optical path of light traveling from the incident port to the emitted port) connecting the incident port of the light for irradiation and the output port of the transmitted light for measurement intersects with the flow of the solution X in the distribution cell, and more. It is preferably orthogonal.

At the tip of the measurement probe 13, a rectangular parallelepiped accommodating portion 131 having an accommodating space 131a is provided. The accommodating portion 131 is provided with a light transmitting portion 131b that transmits the measurement light L1 and the transmitted light L2 on one surface on the measurement probe 13 side. In the accommodation space 131a of the accommodation unit 131, a pair of reflectors 132a and 132b housed in the accommodation unit 131 are provided. The reflector 132a is arranged at a predetermined angle with respect to the extending direction of the optical fiber cable 16 so that the measurement light L1 emitted from the optical fiber cable 16 is reflected 90 degrees toward the reflector 132a. To. The reflector 132b is arranged at a predetermined angle with respect to the reflector 132a so that the measurement light L1 reflected by the reflector 132a is reflected 90 degrees toward the optical fiber cable 17.

Further, in the accommodation space 131a of the accommodation portion 131, a convex lens 133a is arranged between the tip portion 16a of the optical fiber cable 16 and the reflector 132a, and between the tip portion 17a of the optical fiber cable 17 and the reflector 132b. A convex lens 133b is arranged on the. The convex lens 133a suppresses the expansion of the beam diameter of the measurement light L1 emitted from the optical fiber cable 16 toward the reflector 132a. Further, the convex lens 133b suppresses the expansion of the beam diameter of the transmitted light L2 reflected from the reflector 132b toward the optical fiber cable 17. In this way, by providing the convex lenses 133a and 133b to suppress the expansion of the beam diameters of the measurement light L1 and the transmitted light L2, the measurement light L1 emitted from the optical fiber cable 16 is used as the transmitted light L2, and the optical fiber cable 17 is used. It is possible to collect light on the tip portion 17a.

A part of the flow path portion 13b of the measurement probe 13 is cut out from one side surface 13d of the tip portion 13a toward the other side surface 13e. The flow path portion 13b of the measurement probe 13 is provided in the optical path between the reflector 132b and the optical fiber cable 17. By providing the flow path portion 13b in this way, when the measurement light L1 reflected by the reflector 132b passes through the flow path portion 13b, a part of the measurement light L1 due to the solution X that has penetrated into the flow path portion 13b. Is absorbed and becomes transmitted light L2.

As described above, in the present embodiment, the measurement light L1 emitted from the light source unit 12 via the optical fiber cable 16 and the optical fiber cable 17 is detected by the optical fiber cable 16, the optical fiber cable 17, and the reflectors 132a and 132b. An optical path that reflects toward the portion 14 is formed. Then, on the side surface of the tip portion 13a of the measurement probe 13 included in a part of the optical path, a flow path portion 13b is formed in which a part of the side surface of the measurement probe 13 is cut out toward the inside of the measurement probe 13. ing. By providing the measurement probe 13 in this way, the solution X in the pipe 10 invades the flow path portion 13b of the measurement probe 13, and the invading solution X is irradiated with the measurement light L1 from the light source portion 12. At the same time, the transmitted light L2 transmitted through the solution X is conveyed toward the detection unit 14. This enables spectroscopic analysis of the object to be measured contained in the solution X. However, the shape of the measurement probe 13 described above is an example, and the measurement probe 13 may have any shape as long as it can transmit the transmitted light L2 to the detection unit 14.

The detection unit 14 shown in FIG. 1 is a light receiving element that receives the transmitted light L2 of the solution X transmitted from the measurement probe 13 via the optical fiber cable 17, and detects the intensity of the received transmitted light L2.

The calculation unit 15 shown in FIG. 1 calculates the absorbance spectrum of the solution X based on the intensity of the transmitted light L2 detected by the detection unit 14, and based on the absorbance spectrum, the radioactive substance X1 and the solid substance X2 contained in the solution X To analyze. FIG. 3 is a schematic block diagram of the calculation unit according to the present embodiment. The calculation unit 15 is a computer in this embodiment and controls the spectroscopic analyzer 1. As shown in FIG. 3, the calculation unit 15 includes an input unit 20, an output unit 22, a storage unit 24, and a control unit 26. The input unit 20 is a device that receives an operation of an operator, such as a mouse, a keyboard, and a touch panel. The output unit 22 is a device that outputs information, and includes, for example, a display device that displays the control contents of the control unit 26. The storage unit 24 is a memory that stores the calculation contents of the control unit 26, program information, and the like. For example, a RAM (Random Access Memory), a main storage device such as a ROM (Read Only Memory), and an HDD (Hard Disk). Includes at least one of external storage devices such as Disk Drive).

The control unit 26 is an arithmetic unit, that is, a CPU (Central Processing Unit). The control unit 26 includes a light source control unit 30, an absorbance spectrum calculation unit 32, a baseline calculation unit 34, a radioactive substance analysis unit 36, a solid matter analysis unit 38, and an output control unit 40. The control unit 26 stores the light source control unit 30, the absorbance spectrum calculation unit 32, the baseline calculation unit 34, the radioactive substance analysis unit 36, the solid matter analysis unit 38, and the output control unit 40 in the storage unit 24. It is realized by reading the software (program) that has been created, and executes the processing described later.

The light source control unit 30 controls the light source unit 12 to irradiate the light source unit 12 with the measurement light L1.

The absorbance spectrum calculation unit 32 acquires the detection result of the transmitted light L2 by the detection unit 14, and calculates the absorbance spectrum of the solution X based on the detection result. Specifically, the absorbance spectrum calculation unit 32 controls the detection unit 14 to cause the detection unit 14 to receive the transmitted light L2. The absorbance spectrum calculation unit 32 acquires the detection result of the detection unit 14, that is, the information on the intensity of the received transmitted light L2. The absorbance spectrum calculation unit 32 acquires the intensity of each transmitted light L2 for each wavelength. The absorbance spectrum calculation unit 32 calculates the absorbance of the measurement light L1 by the solution X from the ratio of the intensity of the transmitted light L2 to the intensity of the measurement light L1. The absorbance spectrum calculation unit 32 calculates the absorbance of the solution X for each wavelength of the transmitted light L2, and calculates the data obtained by plotting the absorbance for each wavelength as an absorbance spectrum.

FIG. 4 is a graph showing an example of the absorbance spectrum. Since the horizontal axis of FIG. 4 indicates the wavelength and the vertical axis indicates the absorbance of the solution X, the absorbance spectrum A shown in FIG. 4 indicates the absorbance of the solution X for each wavelength. As illustrated in FIG. 4, the absorbance spectrum A of the solution X calculated by the absorbance spectrum calculation unit 32 has a waveform having a peak due to the radioactive substance X1 at at least one wavelength. Here, the wavelength at which the absorbance of the radioactive substance X1 peaks is known. In the spectroscopic analysis, it is possible to calculate the concentration of the radioactive substance X1 from the value of the absorbance at the wavelength of this peak. However, the solution X contains a solid substance X2 in addition to the radioactive substance X1. In this case, in the absorbance spectrum A, the baseline B is deformed due to the influence of the solid substance X2, and the waveform becomes a downward-sloping waveform as shown in FIG. 4, for example. In other words, the absorbance spectrum A is a waveform obtained by superimposing an absorbance spectrum including a peak waveform due to the radioactive substance X1 on a baseline B whose absorbance decreases as the wavelength increases. Since the absorbance spectrum A has such a waveform, when the absorbance of the radioactive substance X1 is calculated based on the peak of the absorbance spectrum A, the absorbance at the peak of the absorbance spectrum A deviates from the absorbance caused by the radioactive substance X1. The calculation accuracy of the concentration of the radioactive substance X1 is lowered. On the other hand, the calculation unit 15 according to the present embodiment calculates the baseline B with high accuracy, and calculates the modified spectrum C obtained by subtracting the baseline B from the absorbance spectrum A. Then, by calculating the concentration of the radioactive substance X1 from the modified spectrum C, it is possible to suppress a decrease in the calculation accuracy of the concentration of the radioactive substance X1. Hereinafter, a specific description will be given. The waveform of the absorbance spectrum A shown in FIG. 4 is an example.

The baseline calculation unit 34 calculates the baseline B from the absorbance spectrum A calculated by the absorbance spectrum calculation unit 32. The baseline calculation unit 34 calculates the baseline B as a straight line in which the absorbance (vertical axis) changes temporarily for each wavelength (horizontal axis). Specifically, the baseline calculation unit 34 calculates the baseline B as a straight line of the following equation (1).

Y = a ・ X + b ・ ・ ・ (1)

In the formula (1), X is the wavelength (horizontal axis) in the absorbance spectrum A, and Y is the absorbance (vertical axis), both of which are variables. Further, the slope a is the slope of the baseline B, and the value is constant (constant). Further, the constant b is an intercept of the baseline B, and the value is constant (constant). The baseline calculation unit 34 calculates the baseline B by calculating the slope a and the constant b from the absorbance spectrum A.

The baseline calculation unit 34 calculates the slope a based on the absorbance at the calculation wavelength W in the absorbance spectrum A. The calculation wavelength W is a wavelength other than the wavelength at which the peak due to the absorption of the radioactive substance X1 is present in the absorbance spectrum A. Specifically, the baseline calculation unit 34 linearly differentiates the value of the absorbance at the calculation wavelength W of the absorbance spectrum A, and calculates the slope a based on the value obtained by the first derivative. Furthermore, it is preferable that the baseline calculation unit 34 sets a plurality of calculation wavelengths W and calculates the first derivative value of the absorbance at each calculation wavelength W. The baseline calculation unit 34 calculates the average value of the first derivative values of the absorbance at each calculation wavelength W, and sets the average value as the slope a. However, the baseline calculation unit 34 is not limited to calculating the average value of the first derivative values of the absorbance at each calculation wavelength W, and sets the first derivative value of the absorbance at one calculation wavelength W as the slope a. You may.

Since the wavelength having the peak of the absorbance of the radioactive substance X1 is known, the wavelength W for calculation is also known to be the wavelength without the peak of the radioactive substance X1 and can be set in advance. Therefore, in the present embodiment, the value of the calculation wavelength W is preset as a wavelength at which the radioactive substance X1 has no peak, and is stored in, for example, the storage unit 24. The baseline calculation unit 34 acquires a preset value of the calculation wavelength W, and calculates the slope a from the first derivative value at the calculation wavelength W. Examples of the wavelength W for calculation include 600 nm, 700 nm, and 900 nm. The baseline calculation unit 34 calculates the first derivative values of the absorbance of the absorbance spectrum A at wavelengths of 600 nm, 700 nm, and 900 nm, respectively, and sets the average value of the first derivative values as the slope a. However, the calculation wavelength W is not limited to 600 nm, 700 nm, and 900 nm, and may be any wavelength as long as there is no peak of the radioactive substance X1.

However, the baseline calculation unit 34 is not limited to using a preset value of the calculation wavelength W, and may calculate the value of the calculation wavelength W from, for example, the absorbance spectrum A. In this case, the baseline calculation unit 34 secondarily differentiates the absorbance value at each wavelength of the absorbance spectrum A, and calculates the calculation wavelength W based on the second derivative value. Specifically, the baseline calculation unit 34 may calculate the wavelength at which the second derivative value becomes zero as the calculation wavelength W.

Further, the baseline calculation unit 34 calculates the slope a based on the first derivative value of the absorbance at the calculation wavelength W, but the calculation method of the slope a is not limited to this, and the slope a is calculated based on the absorbance spectrum A. Anything that does. For example, the baseline calculation unit 34 may calculate an approximate straight line of the absorbance spectrum A at the calculation wavelength W, and set the slope of the approximate straight line as the slope a of the baseline B.

The baseline calculation unit 34 calculates the constant b based on the slope a calculated as described above and the absorbance spectrum A. For example, the baseline calculation unit 34 calculates the constant b from the value of the slope a and the value of the absorbance at one calculation wavelength W. In this case, the baseline calculation unit 34 calculates the constant b so that the slope is the slope a and the straight line passing through the point on the absorbance spectrum A at one calculation wavelength W is the baseline B. In other words, the baseline calculation unit 34 sets the constant b of the baseline B so that the absorbance of the baseline B at one calculation wavelength W is the same as the absorbance in the absorbance spectrum A at the calculation wavelength W. calculate.

The baseline calculation unit 34 calculates the baseline B with high accuracy by calculating the slope a and the constant b in this way. In the present embodiment, since the slope a has a negative value, the baseline B is a straight line whose absorbance decreases as the wavelength increases.

FIG. 5 is a graph showing an example of the modified spectrum. The radioactive substance analysis unit 36 shown in FIG. 3 calculates the spectrum obtained by subtracting the baseline B from the absorbance spectrum A as the modified spectrum C. As illustrated in FIG. 5, since the modified spectrum C is a spectrum obtained by subtracting the baseline B from the absorbance spectrum A, the influence of the solid substance X2 and the like is removed, and the absorbance reflects the absorbance caused by the radioactive substance X1. It becomes a spectrum. That is, in the modified spectrum C, the absorbance at the wavelength where there is no peak due to the absorption of the radioactive substance X1 (calculation wavelength W) becomes almost zero, and the absorbance at the wavelength where there is a peak due to the absorption of the radioactive substance X1 causes the absorption of the radioactive substance X1. It will be the reflected value. Therefore, the radioactive substance analysis unit 36 can calculate the concentration of the radioactive substance X1 with high accuracy by calculating the concentration of the radioactive substance based on the modified spectrum C. For example, the radioactive substance analysis unit 36 acquires the relationship between the concentration of the radioactive substance X1 and the peak value of the absorbance from the storage unit 24, and inputs the peak value of the absorbance in the modified spectrum C into this relationship, whereby the radioactive substance X1 Calculate the concentration of.

As described above, the calculation unit 15 calculates the concentration of the radioactive substance X1 based on the modified spectrum C obtained by subtracting the baseline B from the absorbance spectrum A. Here, when analyzing the solution X, in addition to the analysis of the radioactive substance X1, for example, in order to determine whether the treatment of the solution X is properly performed, it may be required to analyze the solid substance X2 as well. is there. On the other hand, the inventor recalls that the solid matter X2 can be analyzed based on the baseline B, and the arithmetic unit 15 according to the present embodiment can analyze the solid matter X2 together with the radioactive substance X1. It was set to be. Hereinafter, a specific description will be given.

The solid matter analysis unit 38 shown in FIG. 3 calculates the amount of solid matter X2 contained in the solution X based on the baseline B calculated by the baseline calculation unit 34. The inventor recalled that the absorption corresponding to the baseline B was due to the scattering of the measurement light L1 by the solid material X2. That is, it can be said that the absorbance at the baseline B reflects the intensity of the measurement light L1 that did not reach the detection unit 14 due to being scattered by the solid substance X2, not actually absorbed. The amount of scattering of the measurement light L1, that is, the absorbance at the baseline B increases as the amount of the solid substance X2 contained in the solution X increases. Therefore, the solid matter analysis unit 38 can calculate the amount of the solid matter X2 contained in the solution X based on the baseline B showing the absorbance. The amount of solid matter X2 contained in solution X can be rephrased as the concentration of solid matter X2 contained in solution X.

More specifically, the solid matter analysis unit 38 calculates the amount (concentration) of the solid matter X2 for each particle size based on the baseline B. 6 and 7 are graphs of an example for explaining scattering by solid matter. FIG. 6 is a graph showing an example of the amount of scattering by the solid substance X2 for each particle size parameter α. The particle size parameter α is a parameter indicating the relationship between the particle size of the solid substance X2 and the wavelength of the measurement light L1 (incident light). The larger the particle size of the solid matter X2 with respect to the wavelength of the measurement light L1, the larger the value of the particle size parameter α. For example, the particle size parameter α is represented by the following equation (2). In the formula (2), π is the pi, x is the particle size of the solid substance X2, and λ is the wavelength of the measurement light L1.

α = π ・ x / λ ・ ・ ・ (2)

As shown in FIG. 6, in the region where the particle size parameter α is a value α1 or less and the region where the value α2 is larger than the value α1 and the value α2 or less, the amount of light scattered by the solid matter X2 is determined by the particle size parameter α. The larger it becomes, the larger it becomes. Further, in the region where the particle size parameter α is larger than the value α2, the amount of light scattered does not depend much on the size of the particle size parameter α, in other words, the amount of light scattered does not depend on the particle size parameter α. It becomes a constant value. The difference in the tendency of the amount of light scattered for each particle size parameter α is due to the fact that the scattering pattern is different for each particle size parameter α. For example, a solid material X2 having a particle size parameter α larger than the value α2 causes geometric scattering, and a solid material X2 having a particle size parameter α greater than the value α1 and having a value α2 or less causes Mie scattering, and the particle size parameter The solid substance X2 having α having a value of α1 or less causes Rayleigh scattering. For example, the value α1 is 2 and the value α2 is 10, but the values α1 and α2 are not limited to those values.

Here, the particle size parameter α is a value that depends on the wavelength of the measurement light L1 as shown in the equation (2), and becomes smaller as the wavelength of the measurement light L1 becomes larger. Therefore, FIG. 6 can be interpreted as a graph in which the wavelength of the measurement light L1 increases toward the left side on the horizontal axis. Therefore, as shown in FIG. 6, it can be determined that the scattering amount of the solid substance X2 in which the particle size parameter α is larger than the value α2 and causes geometric scattering is constant regardless of the wavelength of the measurement light L1. On the other hand, it can be determined that the scattering amount of the solid substance X2 in which the particle size parameter α is larger than the value α1 and is equal to or less than the value α2 and causes Mie scattering decreases linearly as the wavelength of the measurement light L1 increases. Further, it can be determined that the amount of scattering of the solid material X2 that causes Rayleigh scattering whose particle size parameter α is equal to or less than the value α1 also decreases linearly as the wavelength of the measurement light L1 increases. That is, in the particle size that causes Mie scattering and Rayleigh scattering, the amount of light scattered by the solid matter X2 decreases linearly as the wavelength of the measurement light L1 increases. Further, in the particle size that causes geometric scattering, the value of the amount of light scattered by the solid substance X2 is constant regardless of the wavelength of the measurement light L1. Note that FIG. 6 has a logarithmic scale, and it can be judged that the scattering amount due to Rayleigh scattering is negligibly smaller than the scattering amount due to Mie scattering and the scattering amount due to geometric scattering.

FIG. 7 is a graph showing an example of absorbance for each particle size. FIG. 8 is a graph showing an example of a baseline. As described above, since the amount of scattered light and the absorbance at baseline B correspond to each other, the solid matter analysis unit 38 determines the tendency of the amount of scattered light with respect to the wavelength of the measured light L1 for each particle size. Measurement for each particle size It can be applied as a change tendency of the absorbance of the light L1 with respect to the wavelength for each particle size. Specifically, as shown in FIG. 7A, the solid matter analysis unit 38 is caused by the solid matter X2 having the first particle size (corresponding to the geometric scattering region in which the particle size parameter α is larger than the value α1). It is judged that the absorbance to be obtained becomes a constant value regardless of the wavelength. Further, as shown in FIG. 7B, the solid matter analysis unit 38 has a second particle size (particle size parameter α is larger than the value α1 and becomes a value α2 or less) Mie scattering, which is smaller than the first particle size. It is determined that the absorbance due to the solid substance X2 (corresponding to the region) decreases linearly as the wavelength increases. Further, as shown in FIG. 7C, the solid matter analysis unit 38 has a third particle size (corresponding to a Rayleigh scattering region in which the particle size parameter α is a value α1 or less), which is smaller than the second particle size. It is determined that the absorbance due to the solid substance X2 becomes linearly reduced as the wavelength increases.

The first particle size is a particle size that causes geometric scattering (corresponding to a region where the particle size parameter α is larger than the value α1), and is, for example, 3.5 μm or more, or 2.86 μm or more, for example. The second particle size is a particle size that causes Mie scattering (corresponding to a region where the particle size parameter α is larger than the value α1 and becomes a value α2 or less), for example, 0.13 μm or more and 3.5 μm or less, or, for example, 0. It is .13 μm or more and 2.86 μm or less. The third particle size is a particle size that causes Rayleigh scattering (corresponding to a region where the particle size parameter α is a value α1 or less), and is, for example, 0.13 μm or less. The first particle size, the second particle size, and the third particle size here are constant values having no numerical range within the above numerical range, for example, but the solid matter analysis unit 38 has the first grain. The diameter, the second particle size, and the third particle size may be determined as, for example, a particle size range having a slight numerical range. Since the components of the solution X are basically controlled, for example, by treating with the processing unit F, it can be determined that the particle size of the solid matter is not widely distributed and converges to a constant value.

The solid matter analysis unit 38 includes the absorbance of the solid matter X2 having the first particle size for each wavelength, the absorbance of the solid matter X2 having the second particle size for each wavelength, and the absorbance of the solid matter X2 having the third particle size for each wavelength. It is judged that the sum of and is observed as the baseline B. Since the absorbance and the amount (concentration) of the solid matter X2 are related, the solid matter analysis unit 38 determines the amount of the solid matter X2 for each particle size based on the baseline B, in other words, the slope a and the constant b. Can be calculated in. Specifically, as shown in FIG. 8, the solid matter analysis unit 38 determines that the absorbance in the region B1 of the baseline B is the absorbance caused by the solid matter X2 having the first particle size, and determines that the absorbance is due to the solid matter X2 having the first particle size. The amount (concentration) of the solid matter X2 having the first particle size is calculated based on the absorbance in the region B1 of B. The region B1 is a region (region where Y = b) in which the absorbance is a constant constant b for each waveform. That is, since the absorbance caused by the solid substance X2 having the first particle size is constant regardless of the wavelength, the solid substance analysis unit 38 determines that the absorbance caused by the solid substance X2 having the first particle size is a constant b. Then, the amount (concentration) of the solid matter X2 having the first particle size is calculated based on the constant b.

Further, as shown in FIG. 8, the solid matter analysis unit 38 determines that the absorbance in the region B2 of the baseline B is the absorbance caused by the solid matter X2 having the second particle size, and determines that the absorbance in the region B2 of the baseline B. The amount (concentration) of the solid substance X2 having the second particle size is calculated based on the absorbance at B2. The region B2 is a region (region where Y = a · X) in which the absorbance changes for each waveform with a slope a. That is, since the absorbance due to the solid matter X2 having the second particle size decreases linearly as the wavelength increases, the solid matter analysis unit 38 has an inclination a. The amount (concentration) of the solid matter X2 having the second particle size is calculated based on the slope a. Since the solid substance X2 having the third particle size is in the Rayleigh scattering region, the absorbance due to the solid substance X2 having the third particle size is the absorbance due to the solid substance X2 having the first particle size and the second particle size. Compared to, it is negligibly small. Therefore, the solid matter analysis unit 38 may calculate the concentration of the solid matter X2 having the first particle size and the second particle size without calculating the concentration of the solid matter X2 having the third particle size. However, the solid matter analysis unit 38 may also calculate the concentration of the solid matter X2 having a third particle size. In this case, for example, it may be determined that the sum of the absorbance due to the solid substance X2 having the second particle size and the absorbance due to the solid substance X2 having the third particle size corresponds to the region B2. Then, based on the slope a, the sum of the amounts (concentrations) of the solid matter X2 having the second particle size and the solid matter X2 having the third particle size is calculated, and a predetermined ratio of the sum is the solid having the second particle size. The amount of the substance X2 may be used, and the other may be the amount of the solid substance X2 having a third particle size.

As described above, the solid matter analysis unit 38 calculates the amount of the solid matter X2 contained in the solution X for each particle size of the solid matter X2 based on the baseline B. The output control unit 40 shown in FIG. 3 shows the analysis result of the radioactive substance X1 by the radioactive substance analysis unit 36, here, the concentration of the radioactive substance X1 contained in the solution X, and the analysis result of the solid substance X2 by the solid substance analysis unit 38. Here, the amount of solid material X2 for each particle size for each particle size is output to, for example, the output unit 22. For example, when the amount of the solid matter X2 exceeds a preset threshold value, the output control unit 40 causes the output unit 22 to output to that effect. As a result, the operator can recognize that there is an abnormality in the processing of the solution X, for example, there is an abnormality in the processing in the processing unit F.

The configuration of the spectroscopic analyzer 1 is as described above. Next, the calculation flow of the concentration of the radioactive substance X1 and the amount of the solid substance X2 by the spectroscopic analyzer 1 will be described with reference to the flowchart. FIG. 9 is a flowchart illustrating a calculation flow of the concentration of the radioactive substance and the amount of the solid matter according to the present embodiment. As shown in FIG. 9, the spectroscopic analyzer 1 controls the light source unit 12 by the light source control unit 30, irradiates the solution X with the measurement light L1 from the light source unit 12 (step S10), and causes the solution X by the detection unit 14. The transmitted light L2 from the light source is detected (step S12). The spectroscopic analyzer 1 acquires the detection result of the transmitted light L2 for each wavelength by the absorbance spectrum calculation unit 32, and calculates the absorbance spectrum A (step S14). Then, the spectroscopic analyzer 1 calculates the baseline B based on the absorbance spectrum A by the baseline calculation unit 34 (step S16). The spectroscopic analyzer 1 calculates the concentration of the radioactive substance X1 contained in the solution X based on the modified spectrum C obtained by subtracting the baseline B from the absorbance spectrum A by the radioactive substance analysis unit 36 (step S18). Further, the spectroscopic analyzer 1 calculates the amount of the solid matter X2 contained in the solution X by the solid matter analysis unit 38 based on the baseline B (step S20). The solid matter analysis unit 38 calculates the amount of solid matter X2 for each particle size based on the baseline B.

As described above, the spectroscopic analyzer 1 according to the present embodiment includes a light source unit 12, a detection unit 14, and a calculation unit 15. The light source unit 12 irradiates the solution X containing the radioactive substance X1 and the solid substance X2 other than the radioactive substance X1 with the measurement light L1. The detection unit 14 detects the light transmitted through the solution X, that is, the transmitted light L2. The calculation unit 15 includes an absorbance spectrum calculation unit 32, a baseline calculation unit 34, a radioactive substance analysis unit 36, and a solid matter analysis unit 38. The absorbance spectrum calculation unit 32 calculates the absorbance spectrum A of the solution X from the transmitted light L2 detected by the detection unit 14. The baseline calculation unit 34 calculates the baseline B from the absorbance spectrum A. The radioactive substance analysis unit 36 calculates the concentration of the radioactive substance X1 based on the modified spectrum C obtained by subtracting the baseline B from the absorbance spectrum A. The solid matter analysis unit 38 calculates the amount of solid matter X2 based on the baseline B.

Since the spectroscopic analyzer 1 according to the present embodiment calculates the concentration of the radioactive substance X1 based on the modified spectrum C obtained by subtracting the baseline B from the absorbance spectrum A, the influence of the solid substance X2 can be removed from the spectrum, and the radiation is radioactive. It is possible to suppress a decrease in the calculation accuracy of the concentration of the substance X1. Further, the spectroscopic analyzer 1 can appropriately analyze the solid matter X2 in the solution X by calculating the amount of the solid matter X2 based on the baseline B. Furthermore, the solution X contains the radioactive substance X1, and the equipment configuration for analyzing the components is complicated, for example, as it is divided into a high-dose compartment AR1 and a low-dose compartment AR2. Therefore, it becomes difficult to easily and appropriately analyze the solid substance X2 contained in the solution X. On the other hand, since the spectroscopic analyzer 1 according to the present embodiment calculates the amount of the solid substance X2 based on the baseline B, only the equipment used for the analysis of the radioactive substance X1 is used, and in addition to the analysis of the radioactive substance X1, the solid substance X1 is used. The analysis of X2 can also be easily performed.

Further, when the baseline B is set to Y = a · X + b, the baseline calculation unit 34 calculates the baseline B by calculating the slope a and the constant b of the baseline B from the absorbance spectrum A. .. By treating the baseline B as a straight line, the spectroscopic analyzer 1 can calculate the baseline B with high accuracy, and can appropriately analyze the solid substance X2 while suppressing a decrease in the analysis accuracy of the radioactive substance X1. Can be done.

Further, the baseline calculation unit 34 calculates the slope a based on the absorbance of the absorbance spectrum A at the calculation wavelength W other than the wavelength at which the peak due to the absorption of the radioactive substance X1 in the absorbance spectrum A exists. Since the spectroscopic analyzer 1 calculates the slope a based on the absorbance at the calculation wavelength W, it is possible to calculate the baseline B with high accuracy, and while suppressing a decrease in the analysis accuracy of the radioactive substance X1, a solid substance. The analysis of X2 can be performed appropriately.

Further, the baseline calculation unit 34 calculates the first derivative value of the absorbance of the absorbance spectrum at the calculation wavelength W, and calculates the slope a based on the first derivative value. Since the spectroscopic analyzer 1 calculates the slope a from the first derivative value of the absorbance at the calculation wavelength W, it is possible to calculate the baseline B with high accuracy, and while suppressing the decrease in the analysis accuracy of the radioactive substance X1. , Solid matter X2 can be analyzed appropriately. Further, by using the first derivative value, the data of the absorbance spectrum can be used as it is, so that the baseline B can be easily calculated.

Further, the baseline calculation unit 34 calculates the first derivative value for the plurality of calculation wavelengths W, and calculates the slope a from the average value of the plurality of first derivative values. Since the spectroscopic analyzer 1 calculates the slope a from the average value of a plurality of first-order differential values, it is possible to calculate the baseline B with high accuracy, and it is possible to suppress a decrease in the analysis accuracy of the radioactive substance X1 and solid. The analysis of the object X2 can be performed appropriately.

Further, the solid matter analysis unit 38 calculates the amount of solid matter for each particle size based on the baseline B. Since the spectroscopic analyzer 1 calculates the amount of the solid substance X2 contained in the solution X for each particle size of the solid substance X2, for example, when the amount of the solid substance X2 having a large particle size is large, the treatment of the solution X can be performed. It is possible to determine that it is defective, and it is possible to appropriately analyze the solid substance X2.

Further, the solid matter analysis unit 38 calculates the amount of the solid matter X2 having the first particle size based on the constant b, and based on the slope a, the solid matter X2 having a second particle size smaller than the first particle size. Calculate the amount of. Since the spectroscopic analyzer 1 calculates the amount of the solid matter X2 contained in the solution X for each particle size of the solid matter X2, for example, the analysis of the solid matter X2 can be appropriately performed.

The radioactive substance X1 is at least one of uranium and plutonium. The spectroscopic analyzer 1 can suppress a decrease in the calculation accuracy of the concentrations of uranium and plutonium.

The baseline B is generated not only by the scattering of the measurement light L1 by the solid matter X2 but also by the state of the device of the spectroscopic analyzer 1 such as dirt on the window of the measurement probe 13. In this case, for example, the absorbance spectrum (baseline) measured in a state where the solution X is not flowed through the pipe 10 indicates the state of the device of the spectroscopic analyzer 1. Therefore, from the absorbance spectrum A when the solution X is flown, for example, By subtracting the absorbance spectrum when the solution X is not flown, the influence of the state of the spectroscopic analyzer 1 such as the dirt on the window can be removed.

Further, regarding the particle size of the solid matter X2 in the present embodiment, the method for measuring the particle size is arbitrary, but for example, it is the particle size obtained based on the particle size distribution obtained by the laser diffraction / scattering method. As the particle size distribution, a volume distribution may be used or a number distribution may be used.

Although the embodiments of the present invention have been described above, the embodiments are not limited by the contents of the embodiments. Further, the above-mentioned components include those that can be easily assumed by those skilled in the art, those that are substantially the same, that is, those having a so-called equal range. Furthermore, the components described above can be combined as appropriate. Further, various omissions, replacements or changes of components can be made without departing from the gist of the above-described embodiment.

1 Spectroscopy analyzer 10 Piping 12 Light source unit 13 Measurement probe 14 Detection unit 15 Calculation unit 32 Absorbance spectrum calculation unit 34 Baseline calculation unit 36 Radioactive material analysis unit 38 Solid matter analysis unit A Absorbance spectrum B Baseline C Correction spectrum L1 Measurement light L2 transmitted light

Claims (9)

A light source unit that irradiates a solution containing a radioactive substance and a solid substance other than the radioactive substance with light.
A detector that detects the light transmitted through the solution, and
With a calculation unit,
The calculation unit
An absorbance spectrum calculation unit that calculates the absorbance spectrum of the solution from the light detected by the detection unit,
A baseline calculation unit that calculates a baseline from the absorbance spectrum,
A radioactive substance analysis unit that calculates the concentration of the radioactive substance based on the modified spectrum obtained by subtracting the baseline from the absorbance spectrum.
A solids analysis unit that calculates the amount of the solids based on the baseline,
A spectroscopic analyzer. The baseline,
Y = a · X + b
When
The spectroscopic analyzer according to claim 1, wherein the baseline calculation unit calculates the baseline by calculating the slope a and the constant b of the baseline from the absorbance spectrum.
Here, X is the wavelength of the light in the absorbance spectrum, and Y is the absorbance in the absorbance spectrum. The baseline calculation unit calculates the gradient a based on the absorbance of the absorbance spectrum at a wavelength for calculation, which is a wavelength other than a certain wavelength at which the peak due to absorption of the radioactive substance in the absorbance spectrum is present. The spectroscopic analyzer according to. The spectroscopic analyzer according to claim 3, wherein the baseline calculation unit calculates the first derivative value of the absorbance of the absorbance spectrum at the calculation wavelength, and calculates the slope a based on the first derivative value. The spectroscopic analyzer according to claim 4, wherein the baseline calculation unit calculates the first derivative values for the plurality of the calculation wavelengths, and calculates the slope a from the average value of the plurality of the first derivative values. The spectroscopic analyzer according to any one of claims 2 to 5, wherein the solid matter analysis unit calculates the amount of the solid matter for each particle size based on the baseline. The solid matter analysis unit calculates the amount of the solid matter having a first particle size based on the constant b, and based on the slope a, the solid matter having a second particle size smaller than the first particle size. The spectroscopic analyzer according to claim 6, which calculates the amount of an object. The spectroscopic analyzer according to any one of claims 1 to 7, wherein the radioactive substance is at least one of uranium and plutonium. An irradiation step of irradiating a solution containing a radioactive substance and a solid substance other than the radioactive substance with light, and
A detection step for detecting the light transmitted through the solution and
Including arithmetic steps,
The calculation step is
An absorbance spectrum calculation step for calculating the absorbance spectrum of the solution from the light detected in the detection step, and
A baseline calculation step for calculating a baseline from the absorbance spectrum, and
A radioactive substance analysis step for calculating the concentration of the radioactive substance based on the modified spectrum obtained by subtracting the baseline from the absorbance spectrum.
A solids analysis step that calculates the amount of the solids based on the baseline,
Spectral analysis methods, including.

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