JP2008249328A - Method for analyzing uranium concentration in solution and apparatus for analyzing uranium concentration in solution - Google Patents

Abstract

Calibration is facilitated and the amount of waste is reduced when measuring any ion of uranium and a uranium compound as a measurement target ion and measuring the concentration of the measurement target ion.
In a solution uranium concentration analyzer, a sample container 20 is provided which includes a laser light generator 21 for irradiating a laser beam 1 for exciting a measurement target ion, and a measurement target solution 2 is injected into the path of the laser beam 1. A uranium glass 4 that is a solid calibration standard sample containing ions to be measured at a predetermined concentration is disposed. The fluorescence 3 emitted from the measurement target solution 2 or the uranium glass 4 injected into the sample container 20 reaches the lens 5 through the slit 10 and is condensed, and then the photomultiplier tube through the spectrometer 6. 7 is detected. In the first calibration, calibration is performed by injecting a solution standard sample into the sample container 20, but in the second and subsequent calibrations, calibration is performed using only the uranium glass 4.
[Selection] Figure 1

Description

  The present invention relates to a method for analyzing uranium concentration in a solution, in which any one of uranium and a uranium compound contained in a measurement target solution is used as a measurement target ion, and the concentration of the measurement target ion in the measurement target solution is measured. The present invention relates to an apparatus used for the above.

  In wet uranium waste treatment that dissolves uranium in solution, a method to analyze the uranium concentration in a high concentration range from high to low concentration in real time with high accuracy for process control of the treatment process. Establishment of is desired.

  Conventionally, the uranium concentration in a solution is measured offline after a pretreatment step such as diluting to an appropriate concentration when the sampling sample is at a high concentration and concentrating when the sampling sample is at a low concentration. The method is adopted. For this determination, ICP (Inductively Coupled Plasma) emission analysis (for example, see Non-Patent Document 1) or the like is used.

  However, this method takes several hours from sampling to obtaining the analysis result, and real-time monitoring is not possible. For this reason, it is insufficient as a concentration monitoring technique for efficiently and efficiently managing the chemical reaction treatment process of uranium waste.

Further, a laser excitation time-resolved induced fluorescence analysis method has been developed, and Non-Patent Document 2 discloses an analysis method and apparatus at a laboratory level. In this analysis method, uranium ions in a uranium solution are irradiated with pulsed light such as a laser beam to excite the target ions, and the fluorescence of the uranium-specific wavelength emitted when the excited molecules relax to the ground state is detected. Is. By this analysis method, quantification of the uranium concentration in the solution can be realized in real time.
Daidouji Hidehiro, et al., “Atom spectrum measurement and its application”, Academic Publishing Center, 1989, p. 87-p. 91 Laurent Couston, three others, “Speciation of Uranyl Species in Nitric Acid Medium by Time-Resolved Laser-Induced Fluorescence”, Applied Spectroscopy, Society for Applied Spectroscopy, 1995, Volume 49, Number 3, p. 349-p. 353

  Laser-excited time-resolved induced fluorescence analysis was developed as a technique for analyzing uranium concentration in solution in real time without any pretreatment for adjusting the concentration of the sample. When this analysis method is used, it is necessary to create a calibration curve in advance using a plurality of standard samples of a uranium-containing solution adjusted to a known concentration to maintain the quantitative performance of the analyzer. This requires calibration every time the device is used.

  In addition, when continuously operating for several months to several years, it is necessary to perform recalibration repeatedly at regular intervals. It is difficult to keep the concentration of the standard sample adjusted for the previous calibration for a long period of time, and it is problematic in accuracy to use the same sample repeatedly. Therefore, it is necessary to newly adjust the standard sample every time recalibration is performed.

  Furthermore, even if the standard sample concentration does not cause quality deterioration and is constant, the calibration curve is affected by the fluctuation in the output of the laser used for analysis and the fluctuation in the sensitivity of the detector for measuring fluorescence. Will change, and the quantitative accuracy will decrease.

  For this reason, in the conventional laser excitation time-resolved induced fluorescence analysis method combining the analysis function main body and the apparatus calibration function unit, calibration for quantifying a radiochemically active sample such as a uranium solution is performed as a standard sample. There is a problem that the adjustment is complicated and the time required for cleaning the residual sample after introducing the standard sample is long. In addition, the same standard solution cannot be repeatedly used every time recalibration is required during long-term continuous operation, and there is a problem that a large amount of waste is generated. Furthermore, there is a problem that fluctuations in the calibration curve due to fluctuations in the output of the laser and changes in the sensitivity of the detector for measuring the amount of fluorescence accompanying changes in the installation environment of the analyzer such as the temperature cannot be corrected.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a solution uranium concentration analysis method and a solution uranium concentration analysis apparatus that can be easily calibrated and reduce the amount of waste.

  In order to achieve the above object, the present invention provides a method for analyzing uranium concentration in solution in which any one of uranium and a uranium compound is used as a measurement target ion and the concentration of the measurement target ion is measured. A fluorescence detection step of irradiating excitation light that excites the target, and detecting fluorescence emitted from the excited target ions in the target solution with a fluorescence detector, and calibration of a solid containing the target ions A calibration curve for generating a calibration curve for the fluorescence detector by irradiating the standard sample with the excitation light and detecting fluorescence emitted from the excited ions to be measured in the calibration standard sample with the fluorescence detector Based on the creation step and the calibration curve, concentration determination for obtaining the concentration of the measurement target ion in the measurement target solution from the intensity of the fluorescence detected in the fluorescence detection step And having a degree, the.

  Further, the present invention provides an irradiation for irradiating excitation light for exciting the measurement target ion in an in-solution uranium concentration analyzer that measures the concentration of the measurement target ion using any ion of uranium and a uranium compound as the measurement target ion. Means, a sample container into which the measurement target solution arranged in the path of the excitation light is injected, and a solid calibration standard sample containing the measurement target ions arranged in the path of the excitation light in a predetermined concentration And a fluorescence detector that detects fluorescence emitted from the excited ions to be measured.

  According to the present invention, it is possible to provide a solution uranium concentration analysis method and a solution uranium concentration analysis apparatus that can be easily calibrated and reduce the amount of waste.

  An embodiment of the uranium concentration analyzer in solution according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or similar structure, and the overlapping description is abbreviate | omitted.

[Embodiment 1]
FIG. 1 is a plan view of a uranium concentration analyzer in solution according to Embodiment 1 of the present invention.

  The in-solution uranium concentration analyzer includes a laser light generator 21, a slit 10, a lens 5, a spectrometer 6, a photomultiplier tube 7, a high voltage power supply 9, and a computer 8. Further, the sample container 20 and the plurality of uranium glasses 4 are arranged on the path of the laser light 1 generated from the laser light generator 21 so as not to block the laser light 1 from each other.

  Outside the path of the laser beam 1, a slit 10 having a through hole 22 formed in a flat plate substantially parallel to the laser beam 1 is disposed. A lens 5 is disposed on the opposite side of the sample container 20 and the uranium glass 4 with the slit 10 interposed therebetween, and a spectrometer 6 is disposed on the opposite side of the slit 10 with the lens 5 interposed therebetween. A photomultiplier tube 7 is attached to the spectroscope 6. A high voltage power source 9 and a computer 8 are connected to the photomultiplier tube 7.

This in-solution uranium concentration analyzer irradiates a measurement target with pulsed laser light 1 in the ultraviolet wavelength region to photoexcite the measurement target ion, and detects the fluorescence 3 emitted by the excited ion to perform quantitative analysis. An apparatus that performs analysis by time-resolved laser-induced fluorescence analysis. The uranium solution sample to be measured is the uranyl formate solution 2, and the case where the concentration of uranium (uranyl ion; UO ₂ ²⁺ ) contained in the formic acid solution is quantitatively analyzed will be described as an example.

  In general, uranyl ions in an acidic solution in which uranium dioxide is dissolved have a light absorption wavelength band in the visible to ultraviolet wavelength region (about 200 to about 500 nm), and the absorbance tends to be larger in the short wavelength region. It is known that there is. For this reason, the pulse laser beam 1 is, for example, a fourth harmonic (wavelength 266 nm) or third harmonic (wavelength 355 nm) of an Nd: YAG laser, or a nitrogen laser (wavelength 377 nm), and a pulse time width of 10 ns. Something about can be used. For example, when analyzing the recovered waste liquid decontaminated from the waste produced in the uranium fuel production process, the uranyl formate solution 2 contains uranium at a concentration of about 0.01 to 10000 ppm in several prescribed formic acid solutions.

  Note that the light to be irradiated is not limited to the laser light 1, and any light may be used as long as it excites the measurement target ions, and lamp light may be used.

  A plurality of solid uranium glasses 4 are arranged in the beam path of the pulsed laser beam 1 as a calibration standard sample for calibrating the uranium concentration analyzer 2 in the solution, together with the uranyl formate solution 2 that is the solution to be measured. Yes. Fluorescence 3 emitted from uranyl ions, which are ions to be measured, contained in the uranyl formate solution 2 and the uranium glass 4 is collected by the same lens 5, and photoelectron multiplication that is a fluorescence detector via the spectrometer 6. Detected by tube 7.

  By continuously scanning the inclination of the grating of the spectroscope 6, the spectrum of the fluorescence 3 can be measured. The computer 8 controls the measurement of the fluorescence 3 and displays the result. The output gain when the optical signal detected by the photomultiplier tube 7 is output as an electrical signal is adjusted by the voltage supplied from the high voltage power supply 9.

  Further, among the fluorescence emitted from the sample to be measured and the plurality of calibration standard samples, the fluorescence other than the fluorescence 3 emitted from the selected one sample is shielded so as not to reach the entrance of the spectrometer 6. A slit 10 is provided. The position of the through hole 22 formed in the slit 10 can be moved as appropriate.

Since the uranium glass 4 is used as a standard sample for calibrating the apparatus, it contains, as a main component, uranyl ions (UO ₂ ²⁺ ) identical to the uranium form in the uranyl formate solution. The uranium glass 4 has an optical characteristic that a fluorescence spectrum having a profile similar to that of a uranyl ion in solution is observed. As the uranium glass 4, it is preferable to use one having a uniform uranium concentration distribution inside. In addition, impurities with low impurities and high purity other than uranium components that cause light scattering and absorption are preferable. Furthermore, the glass surface is preferably optically polished and free from fogging.

For calibration of the uranium concentration analyzer in solution, a plurality of uranium glasses 4 having different uranium concentrations are used in a concentration range corresponding to the range (order) of the measurement concentration range required for the uranium concentration analyzer in solution. For example, when measuring the formic acid solution of uranium concentrations in the concentration range spanning ¹⁰⁶ of about 0.01~10000ppm, as can cover the range of 10 ^6, the distribution of the range of uranium concentration 10 ⁶ in uranium glass Give it. In general, uranium in solids tends to emit fluorescence more brightly than uranium in solution. A standard sample can be selected. Although only four uranium glasses 4 are shown in FIG. 1, the number of uranium glasses is not limited to four, and an appropriate number of uranium glasses 4 is used. In this embodiment, seven uranium glasses 4 are arranged on the path of the laser beam 1.

  As a solution standard sample used only for the first calibration of the instrument, it has seven concentrations of 0.01, 0.1, 1, 10, 100, 1000, and 10000 ppm, including the range of the measurement concentration range required for the uranium concentration analyzer in solution. Prepare uranyl formate solution standard.

  The first calibration using the solution standard sample will be described.

  First, a solution standard sample adjusted to a concentration of 0.01 ppm is injected into the sample container 20, and when the pulse laser beam 1 is irradiated, a uranium fluorescence spectrum with respect to the concentration is measured. At this time, a high voltage is supplied from the high voltage power supply 9 in order to ensure the sensitivity of the photomultiplier tube 7. The slit 10 has a geometrical arrangement so as to efficiently collect the fluorescence 3 from the solution standard sample and not to mix the fluorescence from the uranium glass 4.

  Next, the uranium fluorescence spectrum is measured for 0.0001 ppm of the standard sample of the uranium glass 4, and at this time, the slit 10 is set so as to collect only the fluorescence 3 from the uranium glass 4 of 0.0001 ppm, and the solution The distance of the uranium glass 4 from the slit 10 is adjusted so that the intensity, that is, the sensitivity of the fluorescence spectrum of the standard sample and the fluorescence spectrum of the uranium glass 4 match. Thus, the uranium concentration of the solution standard sample and the measured uranium fluorescence spectrum become the first calibration point.

  In this way, the fluorescence spectrum intensities (sensitivity) of the solution standard sample and the uranium glass 4 are sequentially obtained for the second, third,..., Seventh calibration points while keeping the voltage supplied from the high voltage power supply 9 constant. Of the uranium glass 4 is adjusted so as to match.

  FIG. 2 is a graph showing the relationship between the amount of uranium fluorescence and the photomultiplier tube output when the voltages supplied from the high-voltage power supply in the first embodiment are different.

  If the voltage supplied from the high-voltage power supply 9 is constant at the high voltage V1 and the calibration points are sequentially set from the low-concentration solution standard sample to the high concentration, the calibration straight line may be saturated. That is, when the uranium concentration of the solution standard sample is increased, as shown by the dotted line A in FIG. As a result, the linearity between the uranium concentration and the output signal is lost.

  At the calibration point where the voltage supplied from the high voltage power supply 9 is saturated as the high voltage V1, the set voltage is lowered and set to the medium voltage V2. As a result, the linearity of the calibration line can be ensured even in the range where the uranium concentration is C2 to C3 as shown by the broken line B in FIG. Further, the calibration point is sequentially set up to a high concentration, and when a saturated state appears again in the calibration line, the voltage supplied from the high voltage power supply 9 is reset to a low voltage V3 lower than the medium voltage V2. Repeat the same calibration method. As a result, the linearity of the calibration line can be ensured even in the range where the uranium concentration is C3 or higher, as shown by the one-dot chain line C in FIG.

  FIG. 3 is a graph showing the relationship between the wavelength of uranium fluorescence and the photomultiplier tube output when the voltages supplied from the high voltage power supply in the first embodiment are different. FIG. 4 is a graph showing a calibration straight line obtained by correcting the linearity of the photomultiplier tube output in the first embodiment. 3 and 4, the dotted line A indicates that the voltage supplied from the high voltage power supply 9 is the high voltage V1, the broken line B indicates that the voltage supplied from the high voltage power supply 9 is the medium voltage V2, and the alternate long and short dash line C indicates that the voltage is high. A case where the voltage supplied from the voltage power supply 9 is the low voltage V3 is shown.

  By adjusting the voltage supplied from the high-voltage power supply 9 as described above, the intensity (sensitivity) of the uranium fluorescence spectrum is adjusted as shown in FIG. 3, and finally, a plurality of calibration lines as shown in FIG. To obtain a calibration line containing the concentrations of all calibration points.

  In the second and subsequent calibrations, calibration is performed using the uranium glass 4 with the uranium glass 4 adjusted in the first calibration, thereby injecting the solution standard sample into the sample container 20 for calibration. Can be calibrated. In other words, in the second and subsequent calibrations, it is possible to obtain a calibration line with high accuracy by obtaining a calibration point by selecting the concentration from the solid uranium glass 4 of seven different concentrations one by one using the slit 10 one by one. it can.

  As described above, since the solid uranium glass 4 is used for the calibration of the uranium concentration analyzer in the solution of the present embodiment, after the calibration with the solution standard sample is performed only once, each calibration after the second calibration is performed. There is no need to re-adjust the solution standard sample or to use the standard sample once adjusted for stable storage for a long period of time.

  After the calibration straight line is obtained by the calibration, while the measurement target solution is injected into the sample container 20 and the laser light 1 is irradiated, only the fluorescence 3 emitted from the measurement target solution by the slit 10 is spectroscope 6. To enter. The fluorescence 3 incident on the spectroscope 6 is detected by a photomultiplier tube 7 to which a predetermined voltage is applied by a high voltage power source 9. Based on the output of the photomultiplier tube 7 and the calibration curve, the concentration of uranyl ions contained in the solution to be measured can be obtained. At this time, if this concentration deviates from the effective range of the calibration straight line under the condition of the voltage supplied by the high voltage power supply 9, the supplied voltage is appropriately lowered and detected again. That is, when the concentration of uranyl ions exceeds the effective range of the calibration straight line at the high voltage V1 when the voltage supplied by the high voltage power supply 9 is lowered to the medium voltage V2 and the low voltage V3, the appropriate voltage is selected. And rediscover it.

  The operation of obtaining the uranyl ion concentration based on the calibration straight line and the output of the photomultiplier tube 7 may be performed manually outside the solution uranium concentration analyzer, but may be performed by the computer 8. Furthermore, the position of the through hole 22 of the slit 10 may be controlled by the computer 8 so that calibration is automatically performed.

  Conventionally, a plurality of uranium-containing formic acid solution standard samples adjusted to a known concentration are sequentially replaced at the position where the uranyl formate solution 2 is held, and the uranium fluorescence spectrum for each concentration is measured. A calibration line was created from the correlation between the peak intensity, that is, the photomultiplier tube output signal at a specific wavelength and the uranium concentration. Therefore, in the long-term operation of the apparatus, calibration is required periodically, and it is necessary to maintain the quantitative performance by repeating the same calibration not only in the first calibration but also after the second calibration.

  On the other hand, in this embodiment, in order to calibrate an apparatus for quantifying an active sample such as a uranyl formate solution, uranium glass, which is a solid standard sample without aging, is used. For this reason, there is no complication like adjustment of a solution standard sample. Moreover, since the solid standard sample is repeatedly used for calibration, the calibration accuracy is high. Furthermore, it is not necessary to clean the residual sample after introducing the standard sample, and waste can be greatly reduced.

  In addition, when the apparatus is operated continuously for a long period of time, fluctuations in laser output and sensitivity changes in the photomultiplier tube may occur gradually. However, even in this case, if the laser output fluctuation or photomultiplier sensitivity change is daily, it is calibrated daily, and if it is weekly, it is calibrated weekly. It reflects the sensitivity change of the double tube.

[Embodiment 2]
The in-solution uranium concentration analyzer of this embodiment is the same as that of Embodiment 1 except for the uranium glass 4. As in the first embodiment, an example in which the uranium solution sample to be analyzed is a uranyl formate solution and the concentration of uranium (uranium ion; UO ₂ ²⁺ ) contained in the formic acid solution is quantitatively analyzed will be described as an example.

  FIG. 5 is a plan view of the in-solution uranium concentration analyzer according to Embodiment 2 of the present invention.

  In the present embodiment, a plurality of uranium glasses 4 having the same uranium concentration are used. In the first embodiment, the calibration standard samples having different uranium concentrations are used so as to correspond to the range (order) of the measurement concentration range required for the apparatus. On the other hand, in this embodiment, calibration standard samples having different volumes are used so as to correspond to the range of the measurement concentration range required for the apparatus.

For example, when measuring the formic acid solution of uranium concentrations in the concentration range of about 0.01~10000ppm, as can cover the range of 10 ^6, the volume of the uranium glass 4 also to have a distribution in the range of 10 ^6. In general, uranium in solids tends to emit fluorescence more brightly than uranium in solution, so, for example, the uranium concentration in uranium glass is relatively low 100 ppm, and the volume ratio is 0.0001, 0.001, 0.01, 0.1, Seven kinds of uranium glasses of 1, 10, 100 are used.

  Since the amount of fluorescence emitted by each uranium glass 4 is proportional to the volume when the concentration is constant, the case where the concentration of uranium contained in Embodiment 1 is used as a parameter and the case where the volume is used as a parameter are shown. The action is completely equivalent. Therefore, the uranium concentration in the solution can be analyzed by performing the same calibration as in the first embodiment using seven types of uranium glasses 4 having a constant uranium concentration and different volumes as standard samples for calibration.

  According to the present embodiment, as in the first embodiment, there is no complication such as adjustment of the solution standard sample in the second and subsequent calibrations. In addition, it is not necessary to clean the residual sample after introducing the standard sample, and a large amount of waste can be reduced. It is possible to correct variations in the calibration curve due to variations in laser output and fluorescence detector sensitivity.

  Furthermore, since the uranium concentration in the calibration standard sample is constant, it is possible to create a plurality of samples by cutting a sample having a relatively large volume after creating a relatively large calibration standard sample. Even when it is difficult to produce uranium glass containing low or high concentration uranium, an appropriate calibration standard sample can be produced. A calibration standard sample corresponding to the range of the measured concentration range may be created by combining the difference in concentration and the difference in volume.

[Embodiment 3]
The in-solution uranium concentration analyzer of this embodiment is the same as that of Embodiment 1 except that the optical filter 11 is arranged. As in the first embodiment, an example in which the uranium solution sample to be analyzed is a uranyl formate solution and the concentration of uranium (uranium ion; UO ₂ ²⁺ ) contained in the formic acid solution is quantitatively analyzed will be described as an example.

  FIG. 6 is a plan view of the in-solution uranium concentration analyzer according to Embodiment 3 of the present invention.

  The optical filter 11 is disposed between the sample container 20 and the uranium glass 4 and the slit 10. The optical filter 11 can adjust the intensity at which the uranium fluorescence emitted from the measurement target sample and the calibration standard sample is incident on the spectrometer 6.

  In the present embodiment, the high voltage power supply 9 is operated with the voltage supplied to the photomultiplier tube 7 being constant. In the first embodiment, when the voltage supplied from the high voltage power supply 9 to the photomultiplier tube 7 is high and the calibration straight line is saturated, the supplied voltage is lowered to avoid the saturation state. On the other hand, in this embodiment, by reducing the light transmittance of the optical filter 11, an effect equivalent to lowering the voltage supplied to the photomultiplier tube 7 by the high voltage power supply 9 is obtained.

  By changing the light transmittance of the optical filter 11 and performing the same calibration as in the first embodiment, it is possible to obtain a calibration straight line including the concentrations of all calibration points similar to that shown in FIG.

  In this way, after the calibration with the solution standard sample is performed only once, the solution standard sample is readjusted for each calibration after the second time, or the once adjusted standard sample is stored separately for a long period of time and repeatedly. There is no need to use it. In the second and subsequent calibrations, it is possible to obtain a calibration line with high accuracy by obtaining the calibration point by selecting the concentration one by one from the solid uranium glass 4 of seven different concentrations one by one using the slit 10.

  Moreover, since uranium glass, which is a solid standard sample that does not change with time, is used, there is no complication such as adjustment of a solution standard sample. Moreover, since the solid standard sample is repeatedly used for calibration, the calibration accuracy is high. Furthermore, it is not necessary to clean the residual sample after introducing the standard sample, and waste can be greatly reduced. When the apparatus is operated continuously for a long period of time, fluctuations in laser output and sensitivity changes in the photomultiplier tube may occur gradually. However, even in this case, the calibration line reflects the fluctuation of the laser output and the sensitivity change of the photomultiplier tube. Therefore, in order to correct the fluctuation of the laser output and the sensitivity of the photomultiplier tube, the calibration may be performed every day if the fluctuation of the output or the change in sensitivity is a daily unit, and the calibration may be performed every week if the unit is a week. Further, unlike the first embodiment, the high voltage power supply 9 does not need to include means for changing the supplied voltage.

  The above description is merely an example, and the present invention is not limited to the above-described embodiments, and can be implemented in various forms. Moreover, it can also implement combining the characteristic of each embodiment.

It is a top view of the uranium concentration analyzer in a solution of Embodiment 1 concerning the present invention. It is a graph which shows the relationship between the amount of uranium fluorescence in the case where the voltage supplied from the high voltage power supply in Embodiment 1 which concerns on this invention differs, and a photomultiplier tube output. It is a graph which shows the relationship between the wavelength of uranium fluorescence in the case where the voltage supplied from the high voltage power supply in Embodiment 1 which concerns on this invention differs, and a photomultiplier tube output. It is a graph which shows the calibration straight line which correct | amended the linearity of the photomultiplier tube output in Embodiment 1 which concerns on this invention. It is a top view of the uranium concentration analyzer in a solution of Embodiment 2 concerning the present invention. It is a top view of the uranium concentration analyzer in a solution of Embodiment 3 concerning the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Laser light, 2 ... Uranyl formate solution (measuring solution), 3 ... Fluorescence, 4 ... Uranium glass, 5 ... Lens, 6 ... Spectroscope, 7 ... Photomultiplier tube, 8 ... Computer, 9 ... High voltage power supply DESCRIPTION OF SYMBOLS 10 ... Slit, 11 ... Optical filter, 20 ... Sample container, 21 ... Laser light generator, 22 ... Through-hole

Claims (15)

In the method for analyzing uranium concentration in a solution in which any one of uranium and a uranium compound is an ion to be measured and the concentration of the ion to be measured is measured,
A fluorescence detection step of irradiating the measurement target solution with excitation light for exciting the measurement target ion, and detecting fluorescence emitted from the excited measurement target ion in the measurement target solution with a fluorescence detector;
The solid calibration standard sample containing the measurement target ion is irradiated with the excitation light, and fluorescence emitted from the excited measurement target ion in the calibration standard sample is detected by the fluorescence detector. Creating a calibration curve for the fluorescence detector; and
Based on the calibration curve, a concentration determining step for obtaining the concentration of the measurement target ion in the measurement target solution from the intensity of the fluorescence detected in the fluorescence detection step;
A method for analyzing uranium concentration in a solution, comprising: The calibration curve creating step includes
The liquid solution standard sample containing the measurement target ions at a predetermined concentration is irradiated with the excitation light, and fluorescence emitted from the excited measurement target ions in the solution standard sample is detected by the fluorescence detector. A reference fluorescence detection step;
The calibration standard sample is irradiated with the excitation light, and emitted from the excited measurement target ions in the calibration standard sample so that the intensity of fluorescence detected by the fluorescence detector becomes the predetermined concentration. A calibration preparation step for determining a relative position of the calibration standard with respect to the detector;
The calibration standard sample placed at the position determined in the calibration preparation step is irradiated with the excitation light, and the fluorescence emitted from the ions to be measured in the calibration standard sample is emitted by the fluorescence detector. A calibration step of detecting and determining a calibration curve from the relationship between the predetermined concentration and the intensity of fluorescence;
The method for analyzing a uranium concentration in a solution according to claim 1, wherein:   3. The method for analyzing uranium concentration in a solution according to claim 1, further comprising a spectroscopic step for allowing only fluorescence having a predetermined range of energy to enter the fluorescence detector.   4. The method for analyzing uranium concentration in a solution according to claim 1, further comprising a gain adjustment step of adjusting a gain of the fluorescence detector.   The method for analyzing uranium concentration in a solution according to any one of claims 1 to 4, further comprising a fluorescence amount adjustment step of adjusting a fluorescence amount incident on the fluorescence detector. In the uranium concentration analyzer in solution for measuring any ion of uranium and uranium compound as the measurement target ion and measuring the concentration of the measurement target ion,
Irradiation means for irradiating excitation light for exciting the measurement target ions;
A sample container into which a solution to be measured arranged in the path of the excitation light is injected;
A solid calibration standard sample containing a predetermined concentration of the measurement target ions arranged in the path of the excitation light; and
A fluorescence detector for detecting fluorescence emitted from the excited ions to be measured;
A device for analyzing uranium concentration in solution.   7. The apparatus for analyzing uranium concentration in solution according to claim 6, wherein said irradiating means irradiates a laser beam.   7. The apparatus for analyzing uranium concentration in solution according to claim 6, wherein said irradiating means irradiates lamp light.   The calibration standard sample is plural, and the concentration of the measurement target ion contained in at least one calibration standard sample is different from the concentration of the measurement target ion contained in the other calibration standard sample. The apparatus for analyzing uranium concentration in solution according to any one of claims 6 to 8.   10. The calibration standard sample includes a plurality of calibration standards, and the volume of at least one calibration standard sample is different from the volume of the other calibration standard samples. The uranium concentration analyzer in solution as described.   11. The apparatus for analyzing uranium concentration in solution according to claim 6, wherein the calibration standard sample is glass containing the ions to be measured.   The uranium concentration analyzer in solution according to any one of claims 6 to 11, further comprising a spectroscope that causes only fluorescence having a predetermined range of energy to enter the fluorescence detector.   The apparatus for analyzing uranium concentration in solution according to any one of claims 6 to 12, further comprising gain adjusting means for adjusting a gain of the fluorescence detector.   14. The in-solution uranium concentration analyzer according to claim 6, further comprising incident intensity adjusting means for adjusting the incident intensity of the fluorescence to the fluorescence detector.   The fluorescence emitted from the measurement target ions in the calibration standard sample is used to determine the fluorescence emitted from the measurement target solution using a calibration curve created based on the signal detected by the fluorescence detector. The apparatus for analyzing uranium concentration in solution according to any one of claims 6 to 14, further comprising a calibrator for calibrating a signal detected by the fluorescence detector.

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