Device and method for on-line detection of boric acid in nuclear power station primary loop coolant

Abstract

The invention provides a device and a method for on-line detection of boric acid in a primary loop coolant of a nuclear power station. The device comprises a cavity enhancement module, a sample cell, a Raman scattering light collection module and a spectrometer module, the cavity enhancement module comprises a laser, a first spherical mirror and a second spherical mirror; the first spherical mirror and the second spherical mirror are oppositely arranged, and an enhancement cavity is formed between the two; laser emitted by the laser device enters the first spherical mirror, and the incident laser is reflected for multiple times in the first spherical mirror and the second spherical mirror and is converged at a focus position; the sample cell is arranged at the central position of the enhancement cavity, and the laser passes through a to-be-detected solution in the sample cell to generate Raman scattering light; the spectrograph module comprises a slit and a spectrograph; and the light converged by the second converging and collimating lens passes through the slit and enters the spectrometer. By using the method, the boric acid ion concentration in the nuclear power plant primary loop coolant can be rapidly detected in situ without an auxiliary reagent and generating waste liquid.

Description

Technical Field

[0001] The present application relates to the field of nuclear power technology, and in particular to a device and method for online detection of boric acid concentration in a primary-loop coolant of a nuclear power plant. Background Art

[0002] In nuclear power generation technology, boric acid is usually added to the primary coolant of a nuclear power plant's pressurized water reactor. Boron is used to control the reaction of the core and achieve smooth operation of the nuclear power plant. Therefore, accurate measurement of borate ion concentration is crucial to the safe operation of the nuclear power plant.

[0003] In the prior art, the methods for measuring the concentration of boric acid ions that are commonly used in nuclear power plants are the neutron method and the titration method. Among them, the neutron method is to pass a beam of neutrons through a boron solution, and use a neutron detector to record the absorption ratio of neutrons before and after passing through the boron solution to infer the boron content in the solution. However, the measurement accuracy of this method is not high, and it is only used for the rough measurement of the boric acid concentration in the primary coolant of a nuclear power plant and the analysis of its changing trend. The titration method mainly determines the titration endpoint by adding other solutions to cause a sudden change in the pH value. In this process, a large amount of radioactive waste liquid may be generated, and due to human intervention, it may be impossible to accurately measure the boric acid content.

[0004] In summary, since the method of detecting the concentration of boric acid in the primary coolant of a nuclear power plant in the prior art has the shortcomings as mentioned above, how to propose a better device and method for detecting the concentration of boric acid in the primary coolant of a nuclear power plant, so that no auxiliary reagents are required, no waste liquid is generated, and the ion concentration can be detected quickly in situ, is a problem that urgently needs to be solved in this field. Summary of the invention

[0005] In view of this, the present invention provides an apparatus and method for online detection of boric acid in a primary-loop coolant of a nuclear power plant, thereby enabling rapid in-situ detection of ion concentration without the need for auxiliary reagents or generation of waste liquid.

[0006] The technical solution of the present invention is specifically achieved as follows:

[0007] A device for online detection of boric acid in a primary circuit coolant of a nuclear power plant, comprising: a cavity enhancement module, a sample pool, a Raman scattered light collection module and a spectrometer module;

[0008] The cavity enhancement module comprises: a laser, a first spherical mirror and a second spherical mirror; the first spherical mirror and the second spherical mirror are arranged opposite to each other, and an enhancement cavity is formed therebetween; the laser light emitted by the laser is incident on the first spherical mirror, and the incident laser light is reflected multiple times in the first spherical mirror and the second spherical mirror and converges at a focal position;

[0009] The sample pool is arranged at the center of the enhancement cavity, and the laser generates Raman scattered light after passing through the solution to be tested in the sample pool;

[0010] The Raman scattered light collection module comprises: a concave reflector, a first converging collimating lens, a broadband filter and a second converging collimating lens; the concave reflector and the first converging collimating lens are arranged opposite to each other and are respectively arranged at positions on both sides of the enhancement cavity where the first spherical mirror and the second spherical mirror are not arranged; the concave reflector collects and reflects the Raman scattered light to the first converging collimating lens, and the light passes through the broadband filter after passing through the first converging collimating lens and is converged by the second converging collimating lens;

[0011] The spectrometer module comprises: a slit and a spectrometer; the light converged by the second converging collimating lens passes through the slit and enters the spectrometer.

[0012] Preferably, the Raman scattered light collection module further comprises: a plane reflector, wherein the plane reflector is arranged between the first converging collimating lens and the broadband filter, and the light collected and converged by the first converging collimating lens is reflected by the plane reflector and then incident on the broadband filter.

[0013] Preferably, the spectrometer is also provided with a photoelectric detection element.

[0014] Preferably, the sample pool is a square box structure, with a light window disposed on each of the four sides, and a sapphire lens installed on each light window.

[0015] Preferably, the sample pool is made of polytetrafluoroethylene, the diameter of each light window is 10 mm, the sapphire lens is sealed to the light window, and the thickness of each sapphire lens is 1 mm.

[0016] Preferably, the bottom of the sample pool is connected with a liquid inlet pipe and a liquid outlet pipe, and the top is provided with a liquid level detection structure.

[0017] Preferably, the enhancement cavity is a nearly concentric cavity formed by a first spherical mirror and a second spherical mirror.

[0018] Preferably, the focal length of the second converging and collimating lens is greater than the focal length of the first converging and collimating lens.

[0019] Preferably, the diameter of the concave reflector is 30 mm and the radius of curvature is 100 mm.

[0020] A method for online detection of boric acid in a primary circuit coolant of a nuclear power plant comprises the following steps:

[0021] Step A, the laser emits a laser, and the angle and direction of the incident laser are adjusted so that the laser is smoothly incident on the first spherical mirror, and the laser is reflected by the first spherical mirror;

[0022] Step B, adjusting the positions of the first spherical mirror and the second spherical mirror so that the laser light is reflected multiple times between the first spherical mirror and the second spherical mirror and passes through the solution to be tested in the sample pool multiple times to excite Raman scattered light;

[0023] In step C, the concave reflector reflects the Raman scattered light to the first converging collimating lens. The first converging collimating lens collects and converges the Raman scattered light. After the light is reflected by the plane reflector, the laser doped in the Raman scattered light is filtered out by a broadband filter. Finally, the light is converged by the second converging collimating lens, passes through the slit, and enters the spectrometer.

[0024] As can be seen above, in the device and method for online detection of boric acid in the primary coolant of a nuclear power plant in the present invention, by arranging the first spherical mirror and the second spherical mirror relative to each other, an enhancement cavity is formed between the two, so that the incident laser can be reflected multiple times between the first spherical mirror and the second spherical mirror, pass through the focal position multiple times, and converge at the focal position, thereby increasing the laser intensity at the focal position. By placing the sample pool at the focal position, a stronger laser can interact with the solution to be tested in the sample pool, thereby improving the detection sensitivity and accuracy. By arranging a concave reflector and a first converging collimating lens on the other two sides of the enhancement cavity, most of the Raman scattered light can be collected on the first converging collimating lens, thereby improving the collection efficiency and avoiding the loss of Raman scattered light. Therefore, the device and method provided by the present invention can eliminate the need to add auxiliary reagents, no waste liquid is generated during the entire process, and the boric acid concentration in the primary coolant of a nuclear power plant can be detected quickly and non-destructively. Furthermore, by arranging a liquid level detection structure, a liquid inlet pipe and a liquid outlet pipe on the sample pool, the liquid level position of the solution to be tested in the sample pool can be monitored at any time, and the amount of the solution to be tested in the sample pool can be controlled through the liquid inlet and outlet pipes. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of a device for online detection of boric acid in a primary-loop coolant of a nuclear power plant in an embodiment of the present invention.

[0026] Figure 2 Schematic diagram of the structure of the sample pool in the embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0028] like Figure 1 and Figure 2 As shown, the present invention provides an online device for detecting boric acid in a primary circuit coolant of a nuclear power plant, comprising: a cavity enhancement module, a sample pool 4, a Raman scattered light collection module and a spectrometer module;

[0029] The cavity enhancement module comprises: a laser 1, a first spherical mirror 2, and a second spherical mirror 3; the first spherical mirror 2 and the second spherical mirror 3 are arranged opposite to each other, and an enhancement cavity is formed therebetween; the laser light emitted by the laser 1 is incident on the first spherical mirror 2, and the incident laser light is reflected multiple times in the first spherical mirror 2 and the second spherical mirror 3 and converges at a focal position;

[0030] The sample pool 4 is arranged at the center of the enhancement cavity, and the laser generates Raman scattered light after passing through the solution to be tested in the sample pool 4;

[0031] The Raman scattered light collection module comprises: a concave reflector 5, a first converging collimating lens 6, a broadband filter 8 and a second converging collimating lens 9; the concave reflector 5 and the first converging collimating lens 6 are arranged opposite to each other and are respectively arranged at positions on both sides of the enhancement cavity where the first spherical mirror 2 and the second spherical mirror 3 are not arranged; the concave reflector 5 collects and reflects the Raman scattered light to the first converging collimating lens 6, and the light passes through the broadband filter 8 after passing through the first converging collimating lens 6 and is converged by the second converging collimating lens 9;

[0032] The spectrometer module comprises: a slit 10 and a spectrometer 11 ; the light converged by the second converging collimating lens 9 passes through the slit 10 and enters the spectrometer 11 .

[0033] According to the principle of Raman spectroscopy, incident photons interact with molecules of the substance to be measured, and some of the photons will be inelastically scattered, thereby generating light with a specific frequency shift, namely Raman scattered light. Therefore, the type of substance can be determined by the wavelength of the generated Raman scattered light, and the amount of the substance content can be inferred by the intensity of the Raman scattered light (for example, the ion concentration in the solution can be inferred). The intensity of Raman scattered light is mainly related to the intensity of the excitation light and the concentration of the substance to be measured. When the concentration of the substance to be measured is unknown, increasing the intensity of the excitation light is an effective way to improve the sensitivity of Raman spectroscopy.

[0034] In the technical solution of the present invention, by arranging the first spherical mirror 2 and the second spherical mirror 3 opposite to each other, an enhancement cavity is formed between the two, and the laser light emitted by the laser 1 is incident on the first spherical mirror 2, and the laser light can be reflected by the first spherical mirror 2 to the second spherical mirror 3, and then reflected by the second spherical mirror 3 to the first spherical mirror 2, so that the incident laser light is reflected multiple times between the first spherical mirror 2 and the second spherical mirror 3, passes through the focal position multiple times, and converges at the focal position, thereby increasing the laser intensity at the focal position. By placing the sample pool 4 at the focal position, a stronger laser light can interact with the solution to be tested in the sample pool, thereby improving the detection sensitivity and accuracy.

[0035] After the laser interacts with the solution to be tested in the sample pool, Raman scattered light is stimulated. By arranging a concave reflector 5 and a first converging collimating lens 6 on the other two sides of the enhancement cavity, a part of the Raman scattered light is directly incident on the first converging collimating lens 6, and the Raman scattered light emitted to the opposite side of the first converging collimating lens 6 can be collected and converged by the concave reflector 5 and then reflected again on the first converging collimating lens 6, so that most of the Raman scattered light can be collected on the first converging collimating lens 6, thereby improving the collection efficiency and avoiding the loss of Raman scattered light. The light collected and converged by the first converging collimating lens 6 passes through a broadband filter 8 to filter out the laser doped in the Raman scattered light, and finally passes through a slit 10 after being converged by a second converging collimating lens 9 and enters a spectrometer. The intensity of the Raman scattered light is analyzed by the spectrometer, and then the ion concentration in the solution is detected (for example, the concentration of boric acid ions in the primary circuit coolant of a nuclear power plant can be detected).

[0036] It can be seen that in the technical solution of the present invention, Raman spectroscopy is used to detect the borate ion concentration in the primary coolant of a nuclear power plant, so there is no need to add auxiliary reagents, no waste liquid is generated during the whole process, and the borate ion concentration in the primary coolant of a nuclear power plant can be quickly detected in situ.

[0037] In the technical solution of the present invention, a variety of implementation methods can be used to implement the above-mentioned device for online detection of boric acid in the primary circuit coolant of a nuclear power plant. The technical solution of the present invention will be described in detail below by taking one of the implementation methods as an example.

[0038] For example, preferably, in a specific embodiment of the present invention, Figure 1 As shown, the Raman scattered light collection module may further include: a plane reflector 7, wherein the plane reflector 7 is disposed between the first converging collimating lens 6 and the broadband filter 8, and the light collected and converged by the first converging collimating lens 6 is reflected by the plane reflector 7 and then incident on the broadband filter 8, thereby changing the propagation direction of the light, which is beneficial to the shape and volume design of the device.

[0039] For another example, preferably, in a specific embodiment of the present invention, Figure 1 As shown, the spectrometer 11 is also provided with a photoelectric detection element 12 (for example, a charge coupled device CCD), so that the optical signal can be converted into an electrical signal through the photoelectric detection element 12 for processing and analysis.

[0040] In addition, as an example, in a preferred embodiment of the present invention, Figure 2 As shown, the sample pool 4 can be a square box structure, and a light window is respectively arranged on the four sides thereof, and a sapphire lens is installed on each light window.

[0041] In the technical solution of the present invention, reference Figure 2 Light windows 44 and 45 allow the laser to pass through the sample cell and complete the excitation of Raman scattered light, and light windows 46 and 47 allow the Raman scattered light collected by the concave reflector 5 to pass through the sample cell again and enter the first converging collimating lens 6.

[0042] Preferably, as an example, in a specific embodiment of the present invention, the sample pool 4 can be made of polytetrafluoroethylene material, the diameter of each light window can be 10 mm, the sapphire lens is sealed and connected to the light window, and the thickness of each sapphire lens can be 1 mm to ensure light transmittance.

[0043] In addition, as an example, in a preferred embodiment of the present invention, Figure 2 As shown, the bottom of the sample pool 4 is also connected to a liquid inlet pipe 41 and a liquid outlet pipe 42, and the top is provided with a liquid level detection structure 43.

[0044] In the technical solution of the present invention, the liquid level height of the solution to be tested in the sample pool 4 can be monitored in real time through the liquid level detection structure 43. The solution to be tested can enter the sample pool through the liquid inlet pipe 41. When the sample pool is filled with the solution, the liquid inlet is stopped. After the detection is completed, the solution in the sample pool can be discharged through the liquid outlet pipe 42.

[0045] In addition, as an example, in a preferred specific embodiment of the present invention, the enhancement cavity can be a concentric cavity or a nearly concentric cavity formed by the first spherical mirror 2 and the second spherical mirror 3.

[0046] Preferably, as an example, the curvature radius of the first spherical mirror 2 and the second spherical mirror 3 can both be 100 mm, the mirror diameter can both be 50 mm, and the placement interval between the two can be 200 mm.

[0047] In addition, as an example, in a preferred specific embodiment of the present invention, the laser 1 can be a laser with a central wavelength of 532 nm and an output power of 500 mW.

[0048] Preferably, as an example, the laser 1 can output laser light with a wavelength of 785 nm, 632.8 nm, 532 nm, 488 nm, 473 nm, 457 nm, 355 nm, 325 nm, 266 nm and / or 244 nm.

[0049] In addition, as an example, in a preferred specific embodiment of the present invention, the diameter of the concave reflector 5 can be 30 mm, and the radius of curvature can be 100 mm.

[0050] In addition, as an example, in a preferred specific embodiment of the present invention, the broadband filter 8 can be a bandpass filter with a diameter of 1 inch, a 532nm high reflectivity film coated on the surface, and a cut-off depth OD>6.

[0051] In addition, as an example, in a preferred specific embodiment of the present invention, the focal length of the second converging collimating lens 9 can be greater than the focal length of the first converging collimating lens 6; for example, the focal length of the first converging collimating lens 6 can be 100 mm, and the focal length of the second converging collimating lens 9 can be 200 mm.

[0052] In addition, in the technical solution of the present invention, a method for online detection of boric acid in a primary circuit coolant of a nuclear power plant is also provided, comprising the following steps:

[0053] Step 101, laser 1 emits laser, adjusts the angle and direction of the incident laser so that it smoothly hits the first spherical mirror 2, and the first spherical mirror 2 reflects the laser;

[0054] Step 102, adjusting the positions of the first spherical mirror 2 and the second spherical mirror 3, so that the laser light is reflected multiple times between the first spherical mirror 2 and the second spherical mirror 3, and passes through the solution to be tested in the sample pool 4 multiple times to excite Raman scattered light;

[0055] In step 103, the concave reflector 5 reflects the Raman scattered light to the first converging collimating lens 6. The first converging collimating lens 6 collects and converges the Raman scattered light. After the light is reflected by the plane reflector, the laser doped in the Raman scattered light is filtered out by the broadband filter 8. Finally, the light is converged by the second converging collimating lens 9, passes through the slit 10, and enters the spectrometer 11.

[0056] In summary, in the technical solution of the present invention, by arranging the first spherical mirror 2 and the second spherical mirror 3 relative to each other, an enhancement cavity is formed between the two, so that the incident laser can be reflected multiple times between the first spherical mirror 2 and the second spherical mirror 3, pass through the focal position multiple times, and converge at the focal position, thereby increasing the laser intensity at the focal position. By placing the sample pool 4 at the focal position, a stronger laser can interact with the solution to be tested in the sample pool, thereby improving the detection sensitivity and accuracy. By arranging the concave reflector 5 and the first converging collimating lens 6 on the other two sides of the enhancement cavity, most of the Raman scattered light can be collected on the first converging collimating lens 6, thereby improving the collection efficiency and avoiding the loss of Raman scattered light. Therefore, the device and method provided by the present invention do not need to add auxiliary reagents, no waste liquid is generated during the whole process, and the boric acid concentration in the primary circuit coolant of the nuclear power plant can be quickly and non-destructively detected. Furthermore, by arranging a liquid level detection structure 43, a liquid inlet pipe 41 and a liquid outlet pipe 42 on the sample pool, the liquid level position of the solution to be tested in the sample pool can be monitored at any time, and the amount of the solution to be tested in the sample pool can be controlled through the liquid inlet and outlet pipes.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A device for online detection of boric acid in a primary circuit coolant of a nuclear power plant, characterized in that: include: Cavity enhancement module, sample cell, Raman scattered light collection module and spectrometer module; The cavity enhancement module comprises: a laser, a first spherical mirror and a second spherical mirror; the first spherical mirror and the second spherical mirror are arranged opposite to each other, and an enhancement cavity is formed therebetween; the laser light emitted by the laser is incident on the first spherical mirror, and the incident laser light is reflected multiple times in the first spherical mirror and the second spherical mirror and converges at a focal position; The sample pool is arranged at the center of the enhancement cavity, and the laser generates Raman scattered light after passing through the solution to be tested in the sample pool; The Raman scattered light collection module comprises: a concave reflector, a first converging collimating lens, a broadband filter and a second converging collimating lens; the concave reflector and the first converging collimating lens are arranged opposite to each other and are respectively arranged at positions on both sides of the enhancement cavity where the first spherical mirror and the second spherical mirror are not arranged; the concave reflector collects and reflects the Raman scattered light to the first converging collimating lens, and the light passes through the broadband filter after passing through the first converging collimating lens and is converged by the second converging collimating lens; The spectrometer module comprises: a slit and a spectrometer; the light converged by the second converging collimating lens passes through the slit and enters the spectrometer.

2. The device for online detection of boric acid in a primary circuit coolant of a nuclear power plant according to claim 1, characterized in that: The Raman scattered light collection module further includes: a plane reflector, which is arranged between the first converging collimating lens and the broadband filter. The light collected and converged by the first converging collimating lens is reflected by the plane reflector and then incident on the broadband filter.

3. The device for online detection of boric acid in a primary circuit coolant of a nuclear power plant according to claim 1, characterized in that: The spectrometer is also provided with a photoelectric detection element.

4. The device for online detection of boric acid in a primary circuit coolant of a nuclear power plant according to claim 1, characterized in that: The sample pool is a square box structure, and a light window is respectively arranged on the four sides thereof, and a sapphire lens is installed on each light window.

5. The device for online detection of boric acid in a primary circuit coolant of a nuclear power plant according to claim 4, characterized in that: The sample pool is made of polytetrafluoroethylene, the diameter of each light window is 10 mm, the sapphire lens is sealed to the light window, and the thickness of each sapphire lens is 1 mm.

6. The device for online detection of boric acid in a primary circuit coolant of a nuclear power plant according to claim 1, characterized in that: The bottom of the sample pool is connected with a liquid inlet pipe and a liquid outlet pipe, and the top of the sample pool is provided with a liquid level detection structure.

7. The device for online detection of boric acid in a primary circuit coolant of a nuclear power plant according to claim 1, characterized in that: The enhancement cavity is a nearly concentric cavity formed by a first spherical mirror and a second spherical mirror.

8. The device for online detection of boric acid in a primary circuit coolant of a nuclear power plant according to claim 1, characterized in that: The focal length of the second converging and collimating lens is greater than the focal length of the first converging and collimating lens.

9. The device for online detection of boric acid in a primary circuit coolant of a nuclear power plant according to claim 1, characterized in that: The diameter of the concave reflecting mirror is 30 mm, and the radius of curvature is 100 mm.

10. A method for online detection of boric acid in a primary circuit coolant of a nuclear power plant using the device according to any one of claims 1 to 9, characterized in that: The steps include: Step A, the laser emits a laser, and the angle and direction of the incident laser are adjusted so that the laser is smoothly incident on the first spherical mirror, and the laser is reflected by the first spherical mirror; Step B, adjusting the positions of the first spherical mirror and the second spherical mirror so that the laser light is reflected multiple times between the first spherical mirror and the second spherical mirror and passes through the solution to be tested in the sample pool multiple times to excite Raman scattered light; In step C, the concave reflector reflects the Raman scattered light to the first converging collimating lens. The first converging collimating lens collects and converges the Raman scattered light. After the light is reflected by the plane reflector, the laser doped in the Raman scattered light is filtered out by a broadband filter. Finally, the light is converged by the second converging collimating lens, passes through the slit, and enters the spectrometer.

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