Detection system and method of multivalent plutonium in nuclear fuel reprocessing

Abstract

The present invention provides a detection system and method for multivalent plutonium in nuclear fuel reprocessing. The detection system for multivalent plutonium in nuclear fuel reprocessing includes a conveying device, which is used to convey a solution containing multivalent plutonium; the wavelength of the measuring light output by the light source covers the absorption spectrum of the multivalent plutonium, the measuring light is split by a beam splitting unit, and each beam of the output light is incident on a detection cell respectively; the multiple detection cells include a first detection cell, a second detection cell and a third detection cell, and the ratio of the measuring optical path of the measuring light in the second detection cell and the third detection cell to the optical path in the first detection cell is not less than 8 and 40 respectively; the switching unit is used to make the light splitting unit receive the measuring light emitted from each detection cell in time; the electrical signal output by the light splitting unit is sent to the analysis unit; the analysis unit processes the electrical signal according to the absorption spectrum technology to obtain the content of each valence plutonium element in the solution. The present invention has the advantages of accurate detection results and the like.

Description

Technical Field

[0001] The invention relates to nuclear element monitoring, and in particular to a detection system and method for multivalent plutonium elements in nuclear fuel post-processing. Background Art

[0002] The object system analyzed in the nuclear fuel reprocessing process is complex, and there are many radioactive elements in the waste liquid, among which plutonium (Pu) is one of the key elements in nuclear fuel reprocessing. Generally, due to the small difference between the redox potentials of plutonium in different valence states, plutonium has multiple valence states coexisting in a nitric acid environment. The common valence states are Pu(III), Pu(IV), and Pu(VI). In order to recover and purify plutonium, it is necessary to control the valence state of plutonium. The stability of the valence state and the kinetics of the valence adjustment reaction have a great influence on the effect of the nuclear fuel reprocessing process. In order to deeply understand the chemical behavior of plutonium in a nitric acid environment, it is necessary to study the valence state distribution of plutonium in nitric acid solution.

[0003] At present, the main methods for studying the plutonium valence state distribution include ion exchange, extraction, precipitation carrier and a combination of multiple methods to quickly separate plutonium of different valence states. However, such methods are complicated and tedious to operate. During the price adjustment and acid adjustment process, the plutonium valence state is easily changed, destroying the existing valence state balance, and thus the true valence state distribution of plutonium in the solution cannot be obtained, affecting the accuracy of the measurement.

[0004] In addition, the separation technology can be combined with capillary electrophoresis (CE) and inductively coupled plasma mass spectrometry (ICPMS) to separate plutonium of different valence states in different water samples, but the operation is complicated, the instrument is expensive, and it is difficult to use on site. Summary of the invention

[0005] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides a detection system for multivalent plutonium in nuclear fuel post-processing.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A detection system for multivalent plutonium in nuclear fuel reprocessing, the detection system for multivalent plutonium in nuclear fuel reprocessing comprising a conveying device, the conveying device being used to convey a solution containing multivalent plutonium; the detection system for multivalent plutonium in nuclear fuel reprocessing also comprises:

[0008] A light source and a beam splitting unit, wherein the wavelength of the measuring light output by the light source covers the absorption spectrum of the multivalent plutonium element, the measuring light is split by the beam splitting unit, and each beam of the output light is incident on the detection cell respectively;

[0009] A plurality of detection cells, the plurality of detection cells comprising a first detection cell, a second detection cell and a third detection cell, the ratio of the measurement optical path of the measurement light in the second detection cell and the third detection cell to the optical path in the first detection cell being not less than 8 and 40 respectively; the third detection cell comprising a first fluid tube, the first fluid tube having a first inlet, a first fluid channel and a first outlet, the first inlet being connected to the conveying device, and the refraction angle of the measurement light entering the first fluid channel on the wall of the first fluid tube being equal to 90 degrees;

[0010] A switching unit, the switching unit is used to make the light splitting unit receive the measurement light emitted from each detection cell in different time periods;

[0011] A spectroscopic unit, wherein the electrical signal output by the spectroscopic unit is sent to an analysis unit;

[0012] An analysis unit is provided, wherein the analysis unit processes the electrical signal according to an absorption spectrum technique to obtain the content of plutonium elements in various valence states in the solution.

[0013] Another object of the present invention is to provide a method for detecting multivalent plutonium in nuclear fuel reprocessing, which is achieved through the following technical solutions:

[0014] A method for detecting multivalent plutonium in nuclear fuel reprocessing, wherein the method for detecting multivalent plutonium in nuclear fuel reprocessing is:

[0015] Splitting the measuring light emitted by the light source, wherein the wavelength of the measuring light covers the absorption spectrum of the multivalent plutonium element;

[0016] The switching unit enables the spectroscopic unit to receive the measuring light emitted from the plurality of detection cells in different time periods, and the solution to be measured is introduced into the detection cells; the plurality of detection cells include a first detection cell, a second detection cell and a third detection cell, and the ratio of the measuring optical path of the measuring light in the second detection cell and the third detection cell to the optical path in the first detection cell is not less than 8 and 40 respectively; the third detection cell includes a first fluid tube, the first fluid tube has a first inlet, a first fluid channel and a first outlet, the first inlet is connected to a conveying device, and the refraction angle of the measuring light entering the first fluid channel on the wall of the first fluid tube is equal to 90 degrees;

[0017] The electrical signal output by the spectroscopic unit is sent to the analysis unit;

[0018] The analysis unit processes the electrical signal according to the absorption spectrum technology to obtain the content of plutonium elements in various valence states in the solution.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] In order to adapt to the characteristics of different valence plutonium content in plutonium solution, the detection cell is designed specifically to increase the optical path from centimeters to meters, so that non-destructive absorption spectroscopy technology can be applied to the detection of multi-valent plutonium, thus achieving the following technical advantages:

[0021] 1. Accurate test results;

[0022] Adopt absorption spectroscopy technology to analyze multivalent plutonium elements, with fast and high-precision detection;

[0023] The specially designed detection cell is used to make the optical path length ratio of the measuring light in the detection cell reach 10 times or even 100 times or more, thereby increasing the detection sensitivity by ten times, a hundred times or even higher, and enabling the detection of plutonium with extremely low content;

[0024] The conveying device reduces the bubbles in the detection pool and realizes the online cleaning of the detection pool, further improving the detection accuracy;

[0025] 2. The detection process is simple and distortion-free;

[0026] The detection process does not require sample pretreatment and is distortion-free. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The disclosure of the present invention will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only used to illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. In the drawings:

[0028] Figure 1 It is a schematic structural diagram of a detection system for multivalent plutonium in nuclear fuel reprocessing according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] Figure 1 The following description describes the optional embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. In order to explain the technical solution of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand that variations or replacements derived from these embodiments will be within the scope of the present invention. Those skilled in the art will understand that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following optional embodiments, but is only limited by the claims and their equivalents.

[0030] Embodiment 1:

[0031] Figure 1 A schematic diagram of the structure of a detection system for multivalent plutonium in nuclear fuel post-processing according to an embodiment of the present invention is given. Figure 1As shown, the detection system of multivalent plutonium in nuclear fuel reprocessing includes:

[0032] A delivery device, such as a combination of a pump, a valve and a pipeline, which is used to deliver a solution containing multivalent plutonium elements to the detection cell;

[0033] A light source 11 and a beam splitting unit 21, wherein the wavelength of the measuring light output by the light source 11 covers the absorption spectrum of the multivalent plutonium element, the measuring light is split by the beam splitting unit 21, and each beam of the output light is incident on the detection cell respectively; the beam splitting unit is a prior art in the art, such as a combination of a reflector and a transflector, an optical fiber beam splitter, etc.;

[0034] A plurality of detection cells, the plurality of detection cells comprising a first detection cell 31, a second detection cell 32 and a third detection cell 33, the ratio of the measurement optical path of the measurement light in the second detection cell 32 and the third detection cell 33 to the optical path in the first detection cell 31 being not less than 8 and 40 respectively; the third detection cell 33 comprising a first fluid tube, the first fluid tube having a first inlet, a first fluid channel and a first outlet, the first inlet being connected to the conveying device, the refraction angle of the measurement light entering the first fluid channel on the wall of the first fluid tube being equal to 90 degrees, so that the measurement light is only transmitted inside the first fluid tube, such as a container, and will not be emitted from the first fluid tube, ensuring that the measurement light has a long optical path;

[0035] A switching unit 61, the switching unit 61 is used to make the light splitting unit 41 receive the measurement light emitted from each detection cell in different time periods;

[0036] A spectroscopic unit 41, wherein the electrical signal output by the spectroscopic unit 41 is sent to an analysis unit 51;

[0037] The analysis unit 51 processes the electrical signal according to the absorption spectrum technology to obtain the content of plutonium elements in various valence states in the solution.

[0038] In order to achieve a long optical path, further, the second detection cell 32 includes a second fluid tube, the second fluid tube has a second inlet, a second fluid channel and a second outlet, the second inlet is connected to the conveying device, and the refraction angle of the measuring light entering the second fluid channel on the wall of the second fluid tube is equal to 90 degrees, so that the measuring light is only transmitted inside the first fluid tube, such as a container, and will not be emitted from the first fluid tube, ensuring that the measuring light has a long optical path.

[0039] In order to make the measuring light have a longer optical path in the fluid channel in the fluid, further, the first fluid tube and the second fluid tube are respectively made of flexible materials, and the curved fluid tube can increase the optical path of the measuring light within a limited volume.

[0040] In order to deliver the liquids such as the container to be tested, the reference liquid and the cleaning liquid into the detection pool, the delivery device further comprises:

[0041] A multi-channel directional selector valve, the ports of which are respectively connected to containers;

[0042] A first pump, wherein an input end of the first pump is connected to a common end of the multi-channel directional selector valve, and an output end of the first pump is connected to a switching valve;

[0043] A switching valve, the ports of which are respectively connected to the sample container and each detection cell.

[0044] In order to reduce the bubbles in the solution in the detection pool to improve the detection accuracy, the delivery device further includes:

[0045] A sample pool, wherein the inlet and the outlet of the sample pool are respectively connected to the ports of the switching valve;

[0046] A second pump, wherein the second pump is used to connect the sample pool and the sample container after the switching valve is switched.

[0047] In order to ensure that at the same time, only the (measured) output light of one detection cell enters the spectroscopic unit, further, the switching unit is arranged on the optical path between the splitting unit and the multiple detection cells, so that the measurement light selectively enters each detection cell; or, the switching unit is arranged on the optical path between multiple detection values ​​and the spectroscopic unit, so that the measurement light emitted from multiple detection cells at the same time selectively enters the spectroscopic unit.

[0048] The method for detecting multivalent plutonium in nuclear fuel post-processing according to the embodiment of the present invention comprises:

[0049] The measurement light beam emitted by the light source 11 is split, and the wavelength of the measurement light covers the absorption spectrum of the multivalent plutonium element;

[0050] The switching unit 61 enables the spectroscopic unit 41 to receive the measuring light emitted from the plurality of detection cells in different time periods, and the solution to be measured is introduced into the detection cells; the plurality of detection cells include a first detection cell 31, a second detection cell 32 and a third detection cell 33, and the ratio of the measuring optical path of the measuring light in the second detection cell 32 and the third detection cell 33 to the optical path in the first detection cell is not less than 8 and 40, respectively; the third detection cell includes a first fluid tube, the first fluid tube has a first inlet, a first fluid channel and a first outlet, the first inlet is connected to a conveying device, and the refraction angle of the measuring light entering the first fluid channel on the wall of the first fluid tube is equal to 90 degrees;

[0051] The electrical signal output by the spectroscopic unit 41 is sent to the analysis unit 51;

[0052] The analysis unit 51 processes the electrical signal according to the absorption spectrum technology to obtain the content of plutonium elements in various valence states in the solution.

[0053] In order to achieve non-destructive measurement and improve detection accuracy, further, the solution to be tested that does not require chemical reaction is sent to the multiple detection cells.

[0054] In order to ensure that at the same time, only the (measured) output light of one detection cell enters the spectroscopic unit, further, the switching unit is arranged on the optical path between the splitting unit and the multiple detection cells, so that the measurement light selectively enters each detection cell; or, the switching unit is arranged on the optical path between multiple detection values ​​and the spectroscopic unit, so that the measurement light emitted from multiple detection cells at the same time selectively enters the spectroscopic unit.

[0055] In order to reduce the bubbles in the solution in the detection pool to improve the detection accuracy, further, the method of passing the solution to be tested into the detection pool is:

[0056] The switching valve is switched, the second pump is started, and the liquid to be tested in the sample container enters the sample pool, and the inlet and outlet of the sample pool are respectively connected to the port of the switching valve;

[0057] The switching valve is switched, and the first pump works to push the solution to be tested in the sample pool into each detection pool.

[0058] Embodiment 2:

[0059] An application example of the system and method for detecting multivalent plutonium in nuclear fuel reprocessing according to Example 1 of the present invention.

[0060] In this application example, Figure 1 As shown, the light source 11 adopts a halogen-deuterium lamp, and the wavelength range of the output measurement light is 190-1100nm, covering the absorption lines of multivalent plutonium elements, such as the absorption line selected for the valence state III is 600nm, the absorption line selected for the valence state IV is 474nm, and the absorption line selected for the valence state VI is 828nm; the measurement light output by the light source 11 is coupled into the optical fiber; the beam splitting unit 21 adopts an optical fiber beam splitter, so that the measurement light is divided into three beams, which are respectively incident on the detection cell; the switching unit 61 adopts a chopper, so that only one of the three beams passes through the corresponding detection cell at the same time;

[0061] The plurality of detection cells include a first detection cell 31, a second detection cell 32 and a third detection cell 33. The first detection cell 31 adopts a cuvette, and the measurement optical path of the measurement light in the first detection cell 31 is 1 cm; the second detection cell 32 and the third detection cell 33 are both made of a liquid tube made of a flexible material, and the liquid tube has an inlet and an outlet, the inlet is connected to a conveying device, and the outlet is connected to a waste liquid container. The split measurement light enters the liquid to be measured in the liquid tube respectively, and the refraction angle on the wall of the liquid tube is 90 degrees, so that the measurement light enters the liquid to be measured for transmission and will not be emitted from the liquid tube. The optical path of the measurement light in the first detection cell 31 is 10 cm, and the optical path of the measurement light in the third detection cell 33 is 50 cm;

[0062] The output light of each detection cell is coupled into the spectroscopic unit 41 through an optical fiber. The spectroscopic unit 41 adopts a spectrometer. The electrical signal output by the spectrometer is sent to the analysis unit 51. The analysis unit 51 obtains the attenuation caused by the selective absorption of the measurement light by the plutonium elements of different valence states (the detection cells correspond to the valence states, and different detection cells are used for the measurement of plutonium elements of different valence states. The weaker the absorption, the longer the optical path of the corresponding detection cell) in different detection cells according to the electrical signals, and then uses the absorption spectrum technology to process the attenuation of the measurement light, so as to obtain the content of the multivalent plutonium elements;

[0063] The conveying device includes a multi-channel directional selector valve, a first pump, a second pump, a switching valve and a sample pool; the ports of the multi-channel directional selector valve are respectively connected to containers, including a reference liquid container and a cleaning liquid container; the input end of the first pump is connected to the common end of the multi-channel directional selector valve, and the output end is connected to the switching valve; the ports of the switching valve are respectively connected to the sample container and each detection pool. The inlet and outlet of the sample pool are respectively connected to the ports of the switching valve; the second pump is used to connect the sample pool and the sample container after the switching valve is switched.

[0064] The method for detecting multivalent plutonium in nuclear fuel reprocessing according to the embodiment of the present invention, that is, the working method of the system for detecting multivalent plutonium in nuclear fuel reprocessing according to the present embodiment, is as follows:

[0065] The measurement light beam emitted by the light source 11 is split, and the wavelength of the measurement light covers the absorption spectrum of the multivalent plutonium element;

[0066] The switching unit 61 enables the spectroscopic unit 41 to receive the measuring light emitted from the plurality of detection cells in different time periods, and the solution to be tested is introduced into the detection cells; the plurality of detection cells include a first detection cell 31, a second detection cell 32 and a third detection cell 33, and the ratio of the measuring optical path of the measuring light in the second detection cell 32 and the third detection cell 33 to the optical path in the first detection cell 31 is not less than 8 and 40, respectively; the third detection cell 33 includes a first fluid tube, the first fluid tube has a first inlet, a first fluid channel and a first outlet, the first inlet is connected to a conveying device, and the refraction angle of the measuring light entering the first fluid channel on the wall of the first fluid tube is equal to 90 degrees;

[0067] The electrical signal output by the spectroscopic unit 41 is sent to the analysis unit 51;

[0068] The analysis unit 51 processes the electrical signal according to the absorption spectrum technology to obtain the content of plutonium elements in various valence states in the solution;

[0069] In the above process, the solution to be tested is introduced into the detection cell in the following manner:

[0070] The switching valve is switched, the second pump is started, and the liquid to be tested in the sample container enters the sample pool, and the inlet and outlet of the sample pool are respectively connected to the port of the switching valve;

[0071] The switching valve is switched, and the first pump works to push the solution to be tested in the sample pool into each detection pool.

[0072] Embodiment 3:

[0073] The application example of the system and method for detecting multivalent plutonium in nuclear fuel post-processing according to Example 1 of the present invention is different from Example 2 in that:

[0074] The switching unit is arranged on the optical path between the detection cell and the spectroscopic unit, so that the measurement lights emitted simultaneously from the single detection cell selectively enter the spectroscopic unit.

Claims

1. A detection system for multivalent plutonium in nuclear fuel reprocessing, the detection system for multivalent plutonium in nuclear fuel reprocessing comprising a conveying device, the conveying device being used to convey a solution containing multivalent plutonium; characterized in that: The detection system of multivalent plutonium in nuclear fuel reprocessing also includes: A light source and a beam splitting unit, wherein the wavelength of the measuring light output by the light source covers the absorption spectrum of the multivalent plutonium element, the measuring light is split by the beam splitting unit, and each beam of the output light is incident on the detection cell respectively; A plurality of detection cells, the plurality of detection cells comprising a first detection cell, a second detection cell and a third detection cell, the ratio of the measurement optical path of the measurement light in the second detection cell and the third detection cell to the optical path in the first detection cell being not less than 8 and 40 respectively; the third detection cell comprising a first fluid tube, the first fluid tube having a first inlet, a first fluid channel and a first outlet, the first inlet being connected to the conveying device, and the refraction angle of the measurement light entering the first fluid channel on the wall of the first fluid tube being equal to 90 degrees; A switching unit, the switching unit is used to make the light splitting unit receive the measurement light emitted from each detection cell in different time periods; A spectroscopic unit, wherein the electrical signal output by the spectroscopic unit is sent to an analysis unit; An analysis unit is provided, wherein the analysis unit processes the electrical signal according to an absorption spectrum technique to obtain the content of plutonium elements in various valence states in the solution.

2. The detection system for multivalent plutonium in nuclear fuel reprocessing according to claim 1, characterized in that: The second detection cell comprises a second fluid tube having a second inlet, a second fluid channel and a second outlet, the second inlet is connected to the delivery device, and the refraction angle of the measuring light entering the second fluid channel on the wall of the second fluid tube is equal to 90 degrees.

3. The detection system of multivalent plutonium in nuclear fuel reprocessing according to claim 2, characterized in that: The first fluid tube and the second fluid tube are respectively made of flexible materials.

4. The detection system for multivalent plutonium in nuclear fuel reprocessing according to claim 1, characterized in that: The conveying device comprises: A multi-channel directional selector valve, the ports of which are respectively connected to containers; A first pump, wherein an input end of the first pump is connected to a common end of the multi-channel directional selector valve, and an output end of the first pump is connected to a switching valve; A switching valve, the ports of which are respectively connected to the sample container and each detection cell.

5. The detection system for multivalent plutonium in nuclear fuel reprocessing according to claim 4, characterized in that: The conveying device also includes: A sample pool, wherein the inlet and the outlet of the sample pool are respectively connected to the ports of the switching valve; A second pump, wherein the second pump is used to connect the sample pool and the sample container after the switching valve is switched.

6. The detection system for multivalent plutonium in nuclear fuel reprocessing according to claim 1, characterized in that: The switching unit is arranged on the optical path between the beam splitting unit and multiple detection cells, so that the measurement light selectively enters each detection cell; or, the switching unit is arranged on the optical path between multiple detection cells and the spectroscopic unit, so that the measurement light emitted simultaneously from multiple detection cells selectively enters the spectroscopic unit.

7. A method for detecting multivalent plutonium in nuclear fuel reprocessing, wherein the method for detecting multivalent plutonium in nuclear fuel reprocessing is: The measuring light emitted by the light source is split by the beam splitting unit, and the wavelength of the measuring light covers the absorption spectrum line of the multivalent plutonium element; The switching unit enables the spectroscopic unit to receive the measuring light emitted from the plurality of detection cells in different time periods, and the solution to be measured is introduced into the detection cells; the plurality of detection cells include a first detection cell, a second detection cell and a third detection cell, and the ratio of the measuring optical path of the measuring light in the second detection cell and the third detection cell to the optical path in the first detection cell is not less than 8 and 40 respectively; the third detection cell includes a first fluid tube, the first fluid tube has a first inlet, a first fluid channel and a first outlet, the first inlet is connected to a conveying device, and the refraction angle of the measuring light entering the first fluid channel on the wall of the first fluid tube is equal to 90 degrees; The electrical signal output by the spectroscopic unit is sent to the analysis unit; The analysis unit processes the electrical signal according to the absorption spectrum technology to obtain the content of plutonium elements in various valence states in the solution.

8. The method for detecting multivalent plutonium in nuclear fuel post-processing according to claim 7, characterized in that: The test solution that does not require chemical reaction is sent to the multiple detection cells.

9. The method for detecting multivalent plutonium in nuclear fuel post-processing according to claim 7, characterized in that: The switching unit is arranged on the optical path between the beam splitting unit and multiple detection cells, so that the measurement light selectively enters each detection cell; or, the switching unit is arranged on the optical path between multiple detection cells and the spectroscopic unit, so that the measurement light emitted simultaneously from multiple detection cells selectively enters the spectroscopic unit.

10. The method for detecting multivalent plutonium in nuclear fuel post-processing according to claim 7, characterized in that: The method of passing the solution to be tested into the detection cell is: The switching valve is switched, the second pump is started, and the liquid to be tested in the sample container enters the sample pool, and the inlet and outlet of the sample pool are respectively connected to the port of the switching valve; The switching valve is switched, and the first pump works to push the solution to be tested in the sample pool into each detection pool.

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