JP5379046B2 - Non-contact qualitative analysis system and method for boric acid precipitates - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a qualitative analysis system for simply and remotely confirming the presence of a boric acid precipitate. <P>SOLUTION: The qualitative analysis system has an infrared source for irradiating a surface of a to-be-inspected member disposed within a predetermined structure with an infrared ray, an infrared detector for detecting a reflective infrared spectrum generated by the infrared ray irradiated and reflected by the surface of the to-be-inspected member, and a monitoring apparatus for monitoring an infrared absorption band specific to a boric acid within the reflective infrared spectrum detected by the infrared detector. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method for detecting boric acid precipitates, and in particular, a system and method that enables qualitative analysis of boric acid precipitates in a non-contact manner by detecting an infrared absorption band specific to boric acid precipitates. It is about.

In a pressurized water nuclear power plant (hereinafter referred to as PWR), boric acid (H ₃ BO ₃ ) is added to the primary coolant, and neutron absorption by boron is used to control the fission reactivity. For this reason, when the primary coolant leaks for some reason, boric acid in the coolant is deposited on the surface of the primary cooling system piping, and a white solid is generated.

  If solids are found on the surface of the primary cooling system pipe in the power plant, the leakage of the primary coolant is suspected, and it is required to confirm the presence of boric acid in the solids to investigate the cause.

  Conventionally, in order to confirm the presence of boric acid in solids, it was necessary for an operator to enter the reactor containment vessel, collect the solids, and analyze the collected solids directly with an analytical instrument. It was. This is because current analysis methods analyze samples destructively (dissolving in water, combustion, etc.) using atomic absorption photometry, potentiometric titration, etc., or fluorescent X-ray analysis to eliminate environmental influences This is because it was necessary to perform analysis inside a device isolated from the environment using an apparatus, an infrared spectrophotometer, or the like.

  Moreover, there is a method described in Patent Document 1 as an apparatus capable of identifying a fluid leakage point from a conventional process pipe. According to the method described in Patent Document 1, a process pipe covered with a pipe heat insulating material is photographed from the outside by a pipe image photographing means, image data of the photographed process pipe is input to a personal computer, and the image data is stored in the personal computer. Compared with the heat flow analysis model that correlates the fluid temperature and fluid flow, data processing is performed, and the amount of fluid leakage from the process piping covered with piping insulation is measured in a non-contact manner, and the location of the fluid leakage is identified To do.

JP 2002-214063 A

  However, since the primary coolant in operation is high temperature and high pressure (320 ° C, about 16MPa), it is necessary to collect solids while ensuring the safety of workers. A reduction in output is required. Furthermore, the primary system has pipes with a high surface dose equivalent rate, and the work of collecting solids also leads to an increase in the exposure dose of workers.

  In addition, the analysis method using the above atomic absorption photometer, etc. requires limited knowledge and skills for the analytical equipment, so the number of personnel that can be analyzed is limited, and when the analyst is absent from the power plant, the response is delayed and the analysis itself However, since it takes time, it took time to identify the solid component.

  Furthermore, even if the solid material is not boric acid but other white materials that are similar in appearance, it is necessary to perform an instrumental analysis after collecting the solid material. Could lead to.

  Further, according to the method described in Patent Document 1, although the location of the fluid leakage from the process piping is identified in a non-contact manner, even the presence of boric acid in the solid material cannot be confirmed.

  The present invention has been made to solve such a conventional problem, and aims to provide a qualitative analysis system and method capable of simply and simply confirming the presence of boric acid in a solid material in a non-contact manner. It is.

  The non-contact qualitative analysis system for boric acid precipitates according to the present invention includes an infrared source that irradiates infrared rays onto the surface of a member to be inspected arranged in a predetermined structure, and the irradiated infrared ray is the surface of the member to be inspected. And an infrared detector that detects a reflected infrared spectrum generated by reflecting the light, and a monitoring device that monitors an infrared absorption band specific to boric acid in the reflected infrared spectrum detected by the infrared detector.

  Further, the non-contact qualitative analysis method for boric acid precipitates of the present invention includes a step of irradiating infrared rays onto the surface of a member to be inspected in a predetermined structure, and the irradiated infrared rays are reflected on the surface of the member to be inspected. A step of detecting a reflected infrared spectrum generated by the detection, and a step of monitoring the presence or absence of an infrared absorption band peculiar to boric acid in the reflected infrared spectrum detected by the infrared detector.

  According to the boric acid precipitate non-contact qualitative analysis system of this embodiment, it is possible to immediately confirm that the boric acid precipitate is deposited on the surface of a predetermined member. Moreover, even if the predetermined member is in a high radiation dose area, the presence or absence of boric acid deposition can be confirmed without approaching the member, so that the exposure dose of workers can be reduced.

It is a figure which shows the structure of the non-contact qualitative analysis system of the boric acid deposit of this embodiment. It is a figure which shows an example of the reflected infrared spectrum from the surface of the PWR primary system piping which the infrared detector of this embodiment detects. It is a figure which shows the result of having evaluated whether an absorption band is a thing peculiar to boric acid. It is a figure which shows the result of having evaluated the influence which the temperature of the surface of PWR primary system piping has on infrared analysis. It is a figure which shows the result of having evaluated the influence which atmospheric absorption and scattering have on infrared analysis.

  Hereinafter, a non-contact qualitative analysis system for boric acid precipitates and a method thereof according to an embodiment of the present invention will be described in detail with reference to the drawings.

  The non-contact qualitative analysis system and method for boric acid precipitates according to the present embodiment are, for example, infrared rays applied to the solid matter deposited on the surface of a PWR power plant primary cooling system (hereinafter simply referred to as PWR primary system) piping. Irradiate and compare the reflected infrared spectrum of the pipe part (background) with no solid matter and the infrared spectrum reflected from the solid matter, and determine the presence or absence (intensity change) of the boric acid infrared absorption band. The presence or absence is evaluated.

  This eliminates the need for collecting solids from the PWR primary system and does not require time for the analysis, thereby enabling the above-mentioned problems to be solved.

  In addition, in this embodiment, by using two absorption bands peculiar to boric acid, there is no interference with infrared rays emitted from the high-temperature pipes or interference with atmospheric absorption, and in the precipitates in the PWR It enables boric acid to be qualitatively analyzed from a distance.

  In this embodiment, the description will be made using the primary cooling system of the PWR power plant, but the present invention is not limited to this, and may be applied to, for example, a boric acid use site of a boiling water nuclear power plant or other plants. Is possible.

  FIG. 1 is a diagram illustrating a configuration of a non-contact qualitative analysis system for boric acid precipitates according to the present embodiment.

  A reactor containment vessel 1 of a PWR power plant equipped with a non-contact qualitative analysis system 100 for boric acid precipitates of this embodiment accommodates a reactor pressure vessel 3, a pressurizer 4, and a primary cooling system pipe 2.

  In addition, since the PWR primary system provided with the non-contact qualitative analysis system 100 for boric acid precipitates of this embodiment has a configuration almost equivalent to the conventional PWR primary system, some known configurations are described in the drawings. The description is omitted.

  The non-contact qualitative analysis system for boric acid precipitates of the present embodiment includes an infrared source 101 that irradiates boron A deposited on the surface of the PWR primary pipe 2 with an infrared ray 101a having a predetermined irradiation infrared spectrum, and a PWR primary system. An infrared detector 102 that detects reflected light 102 a having a reflected infrared spectrum from boron A deposited on the surface of the pipe 2, and a monitoring facility 5 that is located away from the reactor containment vessel 1. And a monitoring device 103 connected to 102.

  The infrared source 101 of the present embodiment irradiates an inspection target with an infrared ray 101a having a predetermined irradiation infrared spectrum. A commercially available infrared lamp or the like can be used as the infrared source, and the wavelength only needs to cover an area of about 1 μm to 10 μm.

  The infrared detector 102 of the present embodiment detects reflected light 102a having a predetermined reflected infrared spectrum from the boric acid precipitate A deposited on the surface of the PWR primary system pipe 2. A commercially available infrared spectrophotometer may be used as the infrared detector.

  In FIG. 1, the number of the infrared sources 101 and the infrared detectors 102 is shown as one for simplification, but in order to monitor the surface of the piping of the entire PWR primary system, the reactor containment vessel It is preferable to provide a plurality of infrared sources 101 or infrared detectors 102 at appropriate locations in 1 where no blind spots are generated.

  The monitoring apparatus 103 of this embodiment is installed in the monitoring facility 5 located at a position away from the reactor containment vessel 1. Based on the output from the infrared detector 102 in the reactor containment vessel 1, the monitoring device 103 compares the infrared luminous intensity reflected from the solid matter on the surface of the PWR primary system pipe 2 with the reflected infrared luminous intensity in the background. Thus, the presence or absence of boric acid on the surface of the PWR primary pipe 2 is monitored by determining the intensity change of the specific wavelength absorbed by boric acid, and the determination result is displayed on the display unit of the monitoring device 103 or the like.

  FIG. 2 is a diagram illustrating an example of a reflected infrared spectrum from the surface of the PWR primary pipe 2 detected by the infrared detector 102 of the present embodiment.

  The reflected infrared spectrum A in the figure shows the case where the boric acid precipitate A is not deposited on the surface of the PWR primary pipe 2 (background), that is, the stainless steel (hereinafter referred to as the material of the surface of the PWR primary pipe 2). , Which is also referred to as a base).

  As shown in the figure, the reflected infrared spectrum A from stainless steel, which is the material of the surface of the PWR primary pipe 2, has a substantially mountain profile in the wavelength range of 1.3 to 14 μm.

  The reflected infrared spectrum B in the figure shows the reflected infrared spectrum from the boric acid precipitate A deposited on the surface of the PWR primary system pipe 2.

  According to the evaluation by the present inventors, as shown in the figure, a plurality of absorption bands 1 to 4 were confirmed in the reflected infrared spectrum B from the boric acid precipitate deposited on the surface of the PWR primary pipe 2. The wavelength of each absorption band is 1.4 μm to 1.7 μm in absorption band 1, 2.0 to 2.3 μm in absorption band 2, 2.6 to 3.0 μm in absorption band 3, and 3.1 to 3.7 μm in absorption band 4 It is.

  In particular, the present inventors have found that there are absorption bands 1 and 2 peculiar to boric acid also on the high wavenumber side, which has not been studied so far.

  Instruments that analyze boric acid from changes in infrared reflection intensity (infrared spectrophotometers) already exist, but absorption by infrared or airborne substances emitted from substances whose wavelength range measured by these instruments is high. Because of the influence of the environment, it may be difficult to easily analyze distant boric acid with the absorption bands 3 and 4.

  On the other hand, the present inventors have confirmed that boric acid exhibits two characteristic absorption characteristics even in a shorter wavelength range (1.4 to 2.3 μm). Therefore, the monitoring device 103 of the non-contact qualitative analysis system for boric acid precipitates according to the present embodiment monitors the intensity change in the wavelength region where the absorption bands 1 and 2 are located by the above-described method, so that the PWR primary system pipe 2 It is judged that the boric acid precipitate A is deposited on the surface of

  FIG. 3 is a diagram showing the results of evaluating whether the absorption bands 1 to 4 are peculiar to boric acid. As comparative objects, evaluation was performed using oxalic acid, paper waste, and vinyl tape that are used in a power plant and look similar to boric acid.

  In the figure, a reflected infrared spectrum a indicates a reflection spectrum from vinyl tape, a reflected infrared spectrum b indicates a reflection spectrum from paper waste, and a reflected infrared spectrum c indicates a reflection spectrum from oxalic acid. ing. Moreover, the reflected infrared spectrum A shows the reflected infrared spectrum from the base, and the reflected infrared spectrum B shows the reflected infrared spectrum from the boric acid precipitate A.

  As can be seen from the figure, in the absorption bands 3 and 4 within the wavelength band of 2.6 to 14 μm, the absorption bands of the reflected infrared spectrum B and the reflected infrared spectra a and b overlap. On the other hand, for the absorption bands 1 and 2 within the shorter wavelength range of 1.4 to 2.3 μm, the reflected infrared spectrum B and the reflected infrared spectra a to c are not overlapped. Therefore, when the absorption bands 1 and 2 are detected in the reflected infrared spectrum B, it can be determined that boric acid precipitates are deposited on the surface of the PWR primary piping.

  FIG. 4 is a diagram showing the results of evaluating the influence of the surface temperature of the PWR primary piping on the infrared analysis.

  The infrared spectrum d in the figure is an infrared spectrum emitted when the base stainless steel tube is heated to 25 ° C., and the infrared spectrum e is obtained when the base stainless steel tube is heated to 50 ° C. The infrared spectrum is emitted, the infrared spectrum f is an infrared spectrum emitted when the stainless steel tube serving as a base is heated to 100 ° C., and the infrared spectrum g is 200 nm of the stainless steel tube serving as a base. It is an infrared spectrum emitted when heated to ° C., and the infrared spectrum h is an infrared spectrum emitted when a stainless steel tube as a base is heated to 300 ° C. The reflected infrared spectrum A indicates the reflected infrared spectrum from the base.

  As can be seen, the absorption bands 3 and 4 are susceptible to interference by infrared rays emitted from the high-temperature pipe. In particular, it can be seen that as the temperature of the stainless steel tube increases, it becomes more susceptible to influence. On the other hand, the absorption bands 1 and 2 are not easily affected by high-temperature piping. Therefore, it can be seen that it is preferable to detect the boric acid precipitate using the absorption bands 1 and 2.

  FIG. 5 is a diagram showing the results of evaluating the influence of atmospheric absorption and scattering on infrared analysis.

  I in the figure indicates the apparent absorption due to the characteristics of the instrument. “i” and “b” in i indicate wave number peaks absorbed by water vapor in the atmosphere, and “c” indicates a wave number peak absorbed by carbon dioxide in the atmosphere. The reflected infrared spectrum A indicates the reflected infrared spectrum from the base.

  As described above, when the infrared absorption band of the atmosphere overlaps with the absorption band of boric acid, it becomes difficult to analyze boric acid from a long distance, so the infrared absorption of the atmosphere is necessary to enable remote monitoring. It is preferred that the band does not overlap the boric acid absorption band.

  As can be seen from the figure, it is understood that, except for the absorption band 3, it does not overlap with the absorption band due to water vapor or carbon dioxide in the atmosphere. Therefore, it is understood that boric acid analysis from a long distance is possible by detecting boric acid precipitates using the absorption bands 1, 2 and 4.

  As described above, according to the non-contact qualitative analysis system for boric acid precipitates of this embodiment, it is possible to immediately confirm that boric acid precipitates are deposited on the surface of the PWR primary system pipe. Become.

  In the prior art, since it was necessary for the worker to collect the deposits deposited on the surface of the PWR primary system piping and analyze it with an external device, this analysis takes a lot of time. Was required to shut down the reactor and reduce its output. On the other hand, according to the boric acid precipitate non-contact qualitative analysis system of the present embodiment, it is not necessary to collect deposits, analysis work is not necessary, and analysis time is shortened. It becomes possible to improve the accuracy of the first report. In addition, it is possible to reduce the possibility of erroneous determination of reactor shutdown.

100: Non-contact qualitative analysis system for boric acid deposits 101: Infrared source 102: Infrared detector 103: Monitoring device

Claims (6)

An infrared source for irradiating the surface of a member to be inspected arranged in a predetermined structure with infrared rays;
An infrared detector for detecting a reflected infrared spectrum generated by reflecting the irradiated infrared ray on the surface of the inspection target member;
A monitoring device for monitoring an infrared absorption band specific to boric acid in the reflected infrared spectrum detected by the infrared detector;
A non-contact qualitative analysis system for boric acid precipitates. The infrared absorption band specific to boric acid is
2. The non-contact qualitative analysis system for boric acid precipitates according to claim 1, wherein the system is at least one of 1.4 μm to 1.7 μm and 2.0 μm to 2.3 μm.   The non-contact qualitative analysis system for boric acid precipitates according to claim 1, wherein the predetermined structure is a reactor containment vessel. Irradiating infrared rays onto the surface of a member to be inspected in a predetermined structure;
Detecting the reflected infrared spectrum generated by reflecting the irradiated infrared ray on the surface of the member to be inspected;
Monitoring the presence or absence of an infrared absorption band specific to boric acid in the reflected infrared spectrum detected by the infrared detector;
A non-contact qualitative analysis method for boric acid precipitates. The infrared absorption band specific to boric acid is
5. The non-contact qualitative analysis method for boric acid precipitates according to claim 4, wherein the range is at least one of 1.4 μm to 1.7 μm and 2.0 μm to 2.3 μm. 6. The non-contact qualitative analysis method for boric acid precipitates according to claim 4, wherein the predetermined structure is a nuclear reactor containment vessel.

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