Impurity detection system and method, and fusion reaction system

Abstract

An impurity detection system (10) and method, and a nuclear fusion reaction system. The impurity detection system (10) comprises: a laser (101), an optical transmission component (102), a discharge electrode (103), an optical signal collection component (104), and a spectrometer (105). The discharge electrode (103) is located on an inner wall (N) of a reaction chamber of a nuclear fusion reaction apparatus; the laser (101) is configured to emit laser light, and the laser light is directed by means of the optical transmission component (102) toward an area, where the discharge electrode (103) is located, on the inner wall (N) of the reaction chamber, so as to excite the inner wall (N) of the reaction chamber to generate plasma; the discharge electrode (103) is configured to discharge to the inner wall (N) of the reaction chamber and ionize the plasma; the optical signal collection component (104) is configured to collect a spectral signal corresponding to the plasma and transmit the spectral signal to the spectrometer (105); and the spectrometer (105) is configured to analyze the spectral signal to obtain impurity information of the surface of the inner wall (N) of the reaction chamber. The impurity detection system (10) can improve the impurity detection effect.

Description

Impurity detection system and method, fusion reaction system

[0001] This application claims priority to Chinese Patent Application No. 202411566704.5, filed on November 5, 2024, entitled "Impurity Detection System and Method, Fusion Reaction System", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of nuclear fusion technology, and in particular to an impurity detection system and method for the inner wall surface of a nuclear fusion reactor, and a fusion reaction system. Background Technology

[0003] Nuclear fusion technology has been widely studied due to its advantage of being able to generate large amounts of clean energy using inexpensive materials. High-temperature, high-density, and highly confined plasma is a fundamental requirement for achieving nuclear fusion.

[0004] Nuclear fusion reactors (such as tokamak devices) typically generate plasma in a reaction chamber and heat it to the fusion reaction temperature, thereby releasing energy through a fusion reaction. During operation, the heat and particle flow from the plasma interacts with the inner wall surface material of the reaction chamber, causing impurities such as carbon, oxygen, iron, and tungsten to be expelled into the plasma. These impurities generate strong radiation, lowering the plasma temperature and weakening its stability, thus preventing the fusion reaction from occurring. Therefore, understanding the elemental composition of the inner wall surface and reducing impurity generation through various means is crucial for nuclear fusion.

[0005] Currently, lasers are emitted into the inner wall of the reaction chamber to excite the inner wall material to generate plasma, and the spectral signal of this plasma is then collected and analyzed to determine the elemental composition of the inner wall surface. However, the intensity of the spectral signal collected in this method is relatively weak, making it difficult to effectively analyze the elemental composition of the inner wall surface based on the collected spectral signal. Therefore, the overall impurity detection effect on the inner wall of the reaction chamber still needs to be improved. Summary of the Invention

[0006] This application provides an impurity detection system and method for the inner wall surface of a nuclear fusion reactor, as well as a fusion reaction system, which can detect impurities in a large area of ​​the inner wall of the nuclear fusion reactor, thereby improving the overall impurity detection effect of the reaction chamber.

[0007] According to one aspect of the embodiments of this application, an impurity detection system for the inner wall surface of a nuclear fusion reactor is provided. The impurity detection system includes: a laser, an optical transmission component, a discharge electrode, an optical signal acquisition component, and a spectrometer. The discharge electrode is located on the inner wall of the reaction chamber of the nuclear fusion reactor.

[0008] The laser is used to emit laser light, which is directed through the optical transmission component to the area where the discharge electrode is located on the inner wall of the reaction chamber, thereby exciting the inner wall of the reaction chamber to generate plasma.

[0009] The discharge electrode is used to discharge to the inner wall of the reaction chamber to ionize the plasma;

[0010] The optical signal acquisition component is used to acquire the spectral signal corresponding to the plasma and transmit the spectral signal to the spectrometer.

[0011] The spectrometer is used to analyze the spectral signal to obtain information on impurities on the inner wall surface of the reaction chamber.

[0012] According to another aspect of the embodiments of this application, an impurity detection method is provided, applied to the above-described impurity detection system, the method comprising:

[0013] Discharge is applied to the inner wall of the reaction chamber of the nuclear fusion reactor through discharge electrodes;

[0014] A laser is emitted by a laser, which is directed through an optical transmission component to the area where the discharge electrode is located on the inner wall of the reaction chamber, thereby exciting the inner wall of the reaction chamber to generate plasma, and the voltage on the discharge electrode continues to ionize the plasma;

[0015] The optical signal acquisition component acquires the spectral signal corresponding to the plasma and transmits the spectral signal to the spectrometer.

[0016] The spectral signal is analyzed by the spectrometer to obtain impurity information on the inner wall surface of the reaction chamber.

[0017] According to another aspect of the embodiments of this application, a fusion reaction system is provided, the fusion reaction system including a nuclear fusion reaction device and the above-mentioned impurity detection system on the inner wall surface of the nuclear fusion reaction chamber;

[0018] The discharge electrode in the impurity detection system is disposed on the inner wall of the reaction chamber in the nuclear fusion reactor. The impurity detection system is used to detect impurity information on the surface of the inner wall of the reaction chamber in the nuclear fusion reactor.

[0019] The impurity detection system for the inner wall surface of a nuclear fusion reactor provided in this application, in addition to generating plasma by laser excitation of the inner wall, also includes electrodes placed on the inner wall and discharging these electrodes to continue ionizing the laser-excited plasma. This increases the intensity of the plasma's spectral signal, thereby prolonging the plasma's duration. This helps the optical signal acquisition component collect a higher intensity and better quality spectral signal, facilitating more accurate impurity detection by the spectrometer based on this signal, thus improving the impurity detection effect. Attached Figure Description

[0020] Figure 1 is a schematic diagram of the structure of an impurity detection system for the inner wall surface of a nuclear fusion reactor according to an embodiment of this application;

[0021] Figure 2 is a schematic diagram of another impurity detection system for the inner wall surface of a nuclear fusion reactor provided in an embodiment of this application;

[0022] Figure 3 is a schematic diagram of the light path provided by an embodiment of this application, in which light passes through two wedge prisms in sequence;

[0023] Figure 4 is a schematic diagram of a laser-irradiable area on the inner wall of a reaction chamber according to an embodiment of this application;

[0024] Figure 5 is a flowchart of an impurity detection method provided in an embodiment of this application. Detailed Implementation

[0025] Many specific details are set forth in the following description to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed below.

[0026] The terminology used in one or more embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of the one or more embodiments of this application. The singular forms “a,” “the,” and “the” used in one or more embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” used in one or more embodiments of this application refers to and includes any or all possible combinations of one or more associated listed items. The term “at least one” in one or more embodiments of this application means “one or more,” and “a plurality of” means “two or more.” The term “comprising” is an open-ended description and should be understood as “including but not limiting,” and may include other content in addition to what has been described.

[0027] It should be understood that although the terms "first," "second," etc., may be used to describe various information in one or more embodiments of this application, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, "first" may also be referred to as "second" without departing from the scope of one or more embodiments of this application, and similarly, "second" may also be referred to as "first." Depending on the context, the word "if," as used herein, may be interpreted as "when," "in response to a determination," or "when," or "in the event of a determination."

[0028] Currently, nuclear fusion is considered an ideal solution to humanity's energy problems. Nuclear fusion reactions can provide a large amount of clean energy, and the fuel required for these reactions is widely available and relatively inexpensive. Consequently, nuclear fusion reactors are extensively studied, with tokamak devices being one such widely researched type. A tokamak device can include a fusion reaction chamber where plasma is generated. A magnetic field is used to confine the plasma within the chamber, and the plasma's movement is controlled to heat it to the fusion temperature, thus initiating a nuclear fusion reaction.

[0029] During the operation of a tokamak device, plasma interacts with the wall material (PWI). This interaction is highly complex, encompassing, but not limited to, backscattering, adsorption and desorption, and redeposition of high-energy particles by the material, as well as physical and chemical sputtering, single-stage arcing, melting, evaporation and thermal shock, blistering, and delamination of the material itself. These changes can lead to damage to the plasma-facing inner wall surface, deposition of impurity particles on the plasma-facing inner wall surface, and introduction of impurity particles into the core plasma. All of these situations can severely affect the steady-state operation of the plasma. For example, these impurity particles can generate intense radiation, lowering the plasma temperature and weakening plasma stability, thus preventing fusion reactions. Impurity particles can also cause fuel entrapment, further threatening the safe operation of the tokamak device.

[0030] By monitoring and analyzing the composition of the plasma-facing inner wall surface, adjustments can be made to the tokamak device based on this composition, which can help maintain steady-state operation. For example, adjusting plasma control can ensure high-performance plasma confinement and reduce impurity adhesion to the inner wall of the reaction chamber.

[0031] One approach employs laser-induced breakdown spectroscopy (LIBS) to detect impurities on the inner wall of a reaction chamber. In this method, a high-power laser is emitted towards the inner wall, exciting the material to generate plasma. Specifically, this causes the chemical bonds on the surface of the inner wall to break, ionizing chemical elements and forming a high-temperature plasma composed of atoms, free electrons, and ions. Atoms and ions in a high-energy state within this plasma transition to lower energy states, emitting light of characteristic wavelengths, thus generating a corresponding spectral signal. This spectral signal is then collected and analyzed; for example, analyzing the wavelength and intensity of the light allows for impurity detection on the inner wall of the reaction chamber. However, the intensity of the spectral signal generated by this method is relatively low, resulting in a weak spectral signal that is effectively collected for analysis. This can lead to some elements with low concentrations or weak spectral lines going undetected, resulting in poor impurity detection performance. Furthermore, due to the complexity of the optical path or the limitations imposed by the windows on the reaction chamber, a typical LIBS system can only detect impurities at a single point or over a small area on the inner wall of the reaction chamber, resulting in significant limitations in impurity detection. Additionally, to receive more spectral signals, the laser and spectral signal collection components are distributed across multiple windows, placing high demands on the installation environment within the reaction chamber and increasing installation complexity. All these factors limit the overall impurity detection performance within the reaction chamber.

[0032] This application provides an impurity detection system for the inner wall surface of a nuclear fusion reactor chamber. This system can acquire high-quality spectral signals, enabling more accurate impurity detection and improving detection efficiency. The embodiments of this application also relate to an impurity detection method applied to this system, and a fusion reaction system.

[0033] Figure 1 is a schematic diagram of an impurity detection system on the inner wall surface of a nuclear fusion reactor according to an embodiment of this application. The nuclear fusion reactor refers to the reaction chamber in a nuclear fusion reactor device. This reaction chamber is annular and is used to contain plasma for nuclear fusion reactions. The inner wall of the reaction chamber refers to the wall facing the plasma within the reaction chamber.

[0034] As shown in Figure 1, the impurity detection system 10 includes a laser 101, an optical transmission component 102, a discharge electrode 103, an optical signal acquisition component 104, and a spectrometer 105. The discharge electrode 103 is located on the inner wall N of the reaction chamber of the nuclear fusion reactor. In this embodiment, only a small portion of the inner wall N of the reaction chamber where the discharge electrode 103 is located is illustrated. Figure 1 shows an example with multiple discharge electrodes 103 on the inner wall N of the reaction chamber. In some embodiments, only one discharge electrode 103 may be provided on the inner wall N of the reaction chamber. When multiple discharge electrodes 103 are provided on the inner wall N of the reaction chamber, these multiple discharge electrodes 103 may be installed only in a portion of the inner wall N of the reaction chamber, or they may be distributed across the entire surface of the inner wall N of the reaction chamber. These multiple discharge electrodes 103 may be evenly distributed to form an electrode group. In some embodiments, these multiple discharge electrodes 103 may be connected in parallel.

[0035] Laser 101 is used to emit laser light, and the dashed lines in Figure 1 represent the light rays. The laser light is directed through optical transmission assembly 102 to the region where discharge electrode 103 is located on the inner wall N of the reaction chamber, exciting the location in the inner wall N that receives the laser light to generate plasma. The generation of this plasma is accompanied by a corresponding spectral signal. For example, laser 101 can emit high-power pulsed laser light. Discharge electrode 103 is used to discharge onto the inner wall N of the reaction chamber, ionizing the plasma generated by the laser excitation. Before plasma is excited from the inner wall N of the reaction chamber, there may be no electrical connection between discharge electrode 103 and the inner wall N of the reaction chamber. After plasma is excited from the inner wall N of the reaction chamber, the plasma acts as a conductive ion between discharge electrode 103 and the inner wall N of the reaction chamber, connecting the discharge electrode 103 and the inner wall N of the reaction chamber. At this time, the voltage emitted by discharge electrode 103 can continue to ionize the plasma and generate an electric spark, which enhances the spectral signal corresponding to the plasma.

[0036] The optical signal acquisition component 104 is used to acquire the spectral signal corresponding to the plasma. The optical signal acquisition component 104 is positioned where the spectral signal can be received to ensure efficient acquisition of the spectral signal corresponding to the plasma. The dashed line between the inner wall N of the reaction chamber and the optical signal acquisition component 104 in Figure 1 is only a rough illustration of the transmission sequence of the spectral signal between components and does not represent the actual transmission path of the spectral signal.

[0037] The optical signal acquisition component 104 is connected to the spectrometer 105 and transmits the acquired spectral signal to the spectrometer 105. The spectrometer 105 analyzes the received spectral signal to obtain impurity information on the N surface of the inner wall of the reaction chamber. For example, the spectrometer 105 can determine the corresponding spectrum and light intensity of the spectral signal, which is the wavelength characteristic of light. Based on the spectrum and light intensity, the elemental information corresponding to the spectral signal can be determined. Then, by comparing this elemental information with the initial elemental information of the wall material of the N inner wall of the reaction chamber, the impurity information on the N surface of the inner wall of the reaction chamber can be determined.

[0038] In one embodiment, the discharge electrode 103 can be disposed on the inner wall of the bottom or top of the reaction chamber. Since the bottom and top of the reaction chamber typically have a higher amount of impurities, performing impurity detection on the bottom or top of the reaction chamber ensures better impurity detection results. The discharge electrode 103 can also be disposed in any area of ​​the inner wall of the reaction chamber to achieve impurity detection in any area of ​​the inner wall surface of the reaction chamber.

[0039] In summary, the impurity detection system for the inner wall surface of a nuclear fusion reactor provided in this application, in addition to generating plasma by laser excitation of the inner wall, also includes electrodes placed on the inner wall and discharging these electrodes to continue ionizing the laser-excited plasma. This increases the intensity of the plasma's spectral signal, thereby prolonging the plasma's duration. This helps the optical signal acquisition component collect a higher intensity and better quality spectral signal, facilitating more accurate impurity detection by the spectrometer based on this spectral signal, thus improving the impurity detection effect.

[0040] The components of the impurity detection system 10 will be further described below.

[0041] In this embodiment, the discharge electrode 103 can be connected to a power supply to discharge the inner wall N of the reaction chamber based on the current provided by the power supply. In this embodiment, the impurity detection system 10 can also include a pulse power supply (not shown in the figure), that is, the power supply can be a pulse power supply. This pulse power supply can be connected to the discharge electrode 103 and the inner wall N of the reaction chamber, for example, the positive terminal is connected to the discharge electrode 103 and the negative terminal is connected to the inner wall N of the reaction chamber. This pulse power supply is used to apply a pulse voltage between the discharge electrode 103 and the inner wall N of the reaction chamber, and the discharge electrode 103 is used to ionize the plasma excited by the laser based on the pulse voltage. For example, the peak voltage between the positive and negative terminals of the pulse power supply can reach 10 kV or more, and the voltage is adjustable within the range of 0 kV to 10 kV, with a discharge time as low as 1 microsecond. The pulse power supply can be located outside the reaction chamber, and the pulse power supply can be connected to the discharge electrode 103 and the inner wall N of the reaction chamber via wires.

[0042] Using a pulsed power supply can easily generate high voltage to meet the discharge requirements of the discharge electrode 103, while avoiding excessive power consumption and preventing damage to the electrodes and current-carrying wires due to their inability to withstand high power. In some embodiments, the power supply for applying voltage to the discharge electrode 103 may not be a pulsed power supply.

[0043] In this embodiment, the discharge electrode 103 in the impurity detection system 10 can be needle-shaped. Applying a voltage to the needle-shaped discharge electrode 103 concentrates the charge at its end, resulting in a higher charge distribution density at that end. This reduces the voltage required to establish conduction between the discharge electrode 103 and the inner wall N of the reaction chamber, lowering the requirements for the supply voltage. For example, the discharge electrode 103 can be made of a conductive material capable of withstanding high current and high voltage, such as metal or stainless steel. The length of the needle-shaped discharge electrode 103 can range from 1 mm to 15 mm. The diameter of the discharge electrode 103 can be less than 10 mm, for example, from 0.5 to 3 mm. In some implementations, the discharge electrode 103 can also be block-shaped, sheet-shaped, or have other shapes; this embodiment does not limit the specific form.

[0044] In this embodiment, before actual impurity detection, the voltage (e.g., a target voltage value) to be applied between the discharge electrode 103 and the inner wall N of the reaction chamber can be determined through adjustment. This ensures that the discharge electrode 103 has a good working state during impurity detection, reliably continuing to ionize the plasma obtained by laser excitation. For example, the voltage between the discharge electrode 103 and the inner wall N of the reaction chamber can be adjusted, and the breakdown state between them can be observed simultaneously. The discharge electrode 103 can be positioned just before being broken down by the high-voltage pulse current, i.e., just before an electric spark is generated between it and the inner wall N. The voltage applied in this state is determined as the voltage to be applied between the discharge electrode 103 and the inner wall N of the reaction chamber during impurity detection.

[0045] In one debugging method, the two ends of the pulse power supply are connected to the discharge electrode 103 and the inner wall N of the reaction chamber, respectively. The voltage of the pulse power supply is adjusted so that the voltage between the discharge electrode 103 and the inner wall N of the reaction chamber is gradually increased in set steps (such as 100V, 150V, or other values). When an electric spark is just generated between the discharge electrode 103 and the inner wall N of the reaction chamber, the voltage between the positive and negative terminals of the pulse power supply is stopped. In this embodiment, the voltage value between the positive and negative terminals of the pulse power supply at this time is called the voltage critical value. Then, a certain value (such as 200V, 150V, or other values) can be withdrawn from this voltage value. At this time, the discharge electrode 103 and the inner wall N of the reaction chamber are just in a state of not being broken down. This voltage value is determined as the target voltage value. After the above adjustment, the pulse power supply is turned off. When the pulse power supply is turned on again, it can operate directly at the target voltage value.

[0046] In this embodiment, the pulsed power supply transmits a high-voltage pulsed current to the discharge electrode 103, ensuring that the voltage is just enough to prevent breakdown between the discharge electrode 103 and the inner wall N of the reaction chamber. When plasma is generated on the inner wall N of the reaction chamber under the action of the laser, the plasma acts as a conductive medium between the discharge electrode 103 and the inner wall N of the reaction chamber. At this time, breakdown can occur between the discharge electrode 103 and the inner wall N of the reaction chamber, generating an electric spark. This confines the plasma between the discharge electrode 103 and the inner wall N of the reaction chamber, heating and further ionizing the plasma. This enhances the spectral signal corresponding to the plasma, prolongs the decay time of the spectral signal, and improves the signal-to-noise ratio of the acquired spectral signal.

[0047] In some implementations of this application, the optical signal acquisition component 104 can be located inside the reaction chamber to ensure good acquisition of the spectral signals in the reaction chamber. Alternatively, only a portion of the optical signal acquisition component 104 may be located inside the reaction chamber, such as only one end of the optical signal acquisition component 104 being located inside the reaction chamber; or the optical signal acquisition component 104 may be located outside the reaction chamber, as long as it can acquire the spectral signals corresponding to the plasma generated in the reaction chamber. For example, if the reaction chamber has a light-transmitting area or a window, the optical signal acquisition component 104 can be located outside the reaction chamber and acquire spectral signals through the light-transmitting area or window.

[0048] In some embodiments, the optical signal acquisition component 104 can be positioned close to the discharge electrode 103 to facilitate the acquisition of clearer spectral signals and ensure effective spectral signal acquisition. The optical signal acquisition component 104 can be connected to the spectrometer 105 via wires. The spectrometer 105 can be located outside the reaction chamber.

[0049] Figure 2 is a schematic diagram of another impurity detection system for the inner wall surface of a nuclear fusion reactor according to an embodiment of this application. As shown in Figure 2, the optical signal acquisition component 104 may include an optical fiber 1041. The head of the optical fiber 1041 can be positioned close to the discharge electrode 103, and the tail of the optical fiber 1041 can be connected to the spectrometer 105. After acquiring the spectral signal, the optical fiber 1041 can directly transmit it to the spectrometer 105. The optical fiber 1041 is small in size and undergoes a certain degree of deformation, thus achieving a good spectral signal acquisition effect in the reaction chamber. In one embodiment, the optical signal acquisition component 104 may include a light guide or other components capable of acquiring spectral signals.

[0050] Referring again to Figure 2, the optical signal acquisition component 104 may further include a light-receiving lens 1042, which is located between the discharge electrode 103 and the optical fiber 1041. For example, the head of the optical fiber 1041 may be located at the focal point of the light-receiving lens 1042. The spectral signal corresponding to the plasma can be focused onto the head of the optical fiber 1041 by the light-receiving lens 1042. This allows more spectral signal to be directed towards the optical fiber 1041, increasing the intensity of the spectral signal directed towards the optical fiber 1041.

[0051] The structure of the optical transmission component 102 will now be described with reference to Figure 2. In Figure 2, the dashed lines represent light rays, and the area between the two dashed lines can be the region where the light beam is located.

[0052] In this embodiment, the optical signal acquisition component 104 can be located at a different window of the reaction chamber from the laser 101, or they can be located at the same window. In some embodiments, referring to FIG2, the optical transmission component 102 may include a dichroic mirror 1021. The dichroic mirror 1021 transmits and reflects the laser emitted by the laser 101, and reflects specific light, which includes the spectral signal corresponding to the plasma excited by N on the inner wall of the reaction chamber. For example, the wavelength of the laser emitted by the laser 101 may be 1064 nanometers (nm), and the wavelength of the spectral signal corresponding to the plasma is determined by the excited material, such as a wavelength range of 300nm to 800nm. This wavelength range is slightly larger than the visible light range, and the dichroic mirror 1021 can reflect visible light. For example, the reflection efficiency of the dichroic mirror 1021 for visible light can reach 99%, and the transmission efficiency for laser light can reach 99.9%.

[0053] Referring to Figure 2, the laser 101 and the optical signal acquisition component 104 can be located on opposite sides of the dichroic mirror 1021. These opposite sides effectively divide the space into two parts using the plane of the dichroic mirror 1021, with each part located on one side of the mirror. The angle between the mirror surface of the dichroic mirror 1021 and the laser optical axis can be 45 degrees. The laser emitted by the laser 101 passes through the dichroic mirror 1021 and strikes the inner wall N of the reaction chamber, exciting plasma and generating a spectral signal. Due to the reversibility of the optical path, this spectral signal can be transmitted in the opposite direction of the laser transmission and to the dichroic mirror 1021. Because of the dichroism of the dichroic mirror 1021, the spectral signal is reflected from the mirror and transmitted to the optical signal acquisition component 104. The spectral signal can also be reflected to the light-receiving lens 1042, which then focuses it onto the optical fiber 1041.

[0054] Some of the spectral signal from the plasma may not be directed to the dichroic mirror 1021 and therefore cannot be collected. However, due to the function of the discharge electrode 103, the intensity and duration of this spectral signal are relatively strong, so the collected spectral signal is sufficient for analysis. Even if some spectral signal cannot be collected, it will not affect the impurity detection effect. This portion of the signal is not considered in this embodiment.

[0055] In this embodiment, the dichroic mirror 1021 enables the collection of spectral signals from the direction of laser emission. This allows for the transmission and reception of light through a single window in the reaction chamber, reducing the complexity of setting up the impurity detection system within the reaction chamber.

[0056] In one embodiment, referring to FIG2, the optical transmission assembly 102 may include a beam expander 1022 for collimating and expanding the incident laser beam. This reduces the energy density during laser transmission, resulting in a smaller spot size and higher energy density at the laser focal point, ensuring more effective excitation of the material on the inner wall N of the reaction chamber. Since the laser beam quality is determined by the laser itself and is a constant value, numerically equal to the divergence angle multiplied by the beam waist radius, after collimation and beam expansion, the original spot diameter increases. Therefore, when focusing at the same focal point, the divergence angle at the focal point will be larger, correspondingly reducing the focal diameter and the spot area at the focal point. Because the total energy of the laser remains constant, the energy density at the focal point increases.

[0057] In one embodiment, referring further to FIG2, the optical transmission assembly 102 may include a focusing lens 1023. The focusing lens 1023 is used to focus the incident laser, and the inner wall N of the reaction chamber may be located at the focal point of the focusing lens 1023. This allows the laser to form a very small spot of high energy density on the inner wall N of the reaction chamber, so as to effectively excite the material on the inner wall N of the reaction chamber to form plasma.

[0058] In this embodiment, the optical transmission component 102 may include only one of the beam expander 1022 and the focusing lens 1023, or it may include both the beam expander 1022 and the focusing lens 1023 (Figure 2 illustrates this case). When both the beam expander 1022 and the focusing lens 1023 are included, the focusing lens 1023 may be located after the beam expander 1022. The laser beam is collimated and expanded by the beam expander 1022 in sequence, and then focused onto the inner wall N of the reaction chamber by the focusing lens 1023.

[0059] Figure 2 shows an example where the focusing lens 1023 is located in front of the dichroic mirror 1021. In some embodiments, the focusing lens 1023 may also be located after the dichroic mirror 1021, that is, the dichroic mirror 1021 is located between the beam expander 1022 and the focusing lens 1023.

[0060] In this embodiment, the optical transmission component 102 can either ensure that the laser beam continues to propagate along its emission direction or adjust the emission direction of the laser beam. For example, the optical transmission component 102 may include an optical deflection component, which is used to deflect the transmission direction of the laser beam from its original direction, and can also control the deflection direction and deflection angle.

[0061] In one embodiment, referring to FIG2, the optical transmission component 102 may include a first wedge prism 1024 and a second wedge prism 1025. A wedge prism is a prism with a certain angle between its incident and emitting surfaces. In some embodiments, the first wedge prism 1024 and the second wedge prism 1025 may be optical wedges, with a small apex angle (i.e., the angle between the incident and emitting surfaces, hereinafter referred to as the wedge angle), such as less than 1 / 10 radian. The apex angle of the two wedge prisms may not be limited to this angle; it can be determined based on the distance between the apex angle and the inner wall N of the reaction chamber, and the required laser scanning range on the inner wall N. For example, the angle may be less than 20 degrees, within 10 degrees, or between 10 and 20 degrees.

[0062] The laser emitted by laser 101 can sequentially pass through a first wedge prism 1024 and a second wedge prism 1025 towards the inner wall N of the reaction chamber. These two wedge prisms form a light deflection component, and the combination of the first wedge prism 1024 and the second wedge prism 1025 can deflect the transmission direction of the passing laser. The relative position or state of the two wedge prisms is adjustable. By placing the relative positions of the first wedge prism 1024 and the second wedge prism 1025 in different states, the passing laser can be directed to different locations. This achieves plasma excitation at different locations on the inner wall N of the reaction chamber, expanding the area within the inner wall N that can receive the laser, thereby enabling the detection of impurities at more locations on the inner wall N of the reaction chamber and improving the overall impurity detection effect on the inner wall of the reaction chamber.

[0063] Figure 3 is a schematic diagram of the optical path of light passing through two wedge prisms in sequence according to an embodiment of this application. Figure 4 is a schematic diagram of the irradiable area of ​​a laser on the inner wall of a reaction chamber according to an embodiment of this application. As shown in Figure 3, the light enters the first wedge prism 1024 along the optical axis of the wedge prism. When it exits from the first wedge prism 1024, the transmission direction can be slightly deflected outward from the plane of the paper. Then it enters the second wedge prism 1025, causing the transmission direction of the light to be deflected upward. The irradiable area Q of the laser on the inner wall N of the reaction chamber shown in Figure 4 can be a region of the inner wall N of the reaction chamber in the left view of Figure 3. For example, through this combination of the two wedge prisms, the laser can be directed to the upper right position of the irradiable area Q shown in Figure 4, such as point W in the area Q.

[0064] In some embodiments, referring further to Figures 2 and 3, the target cross-sections of both the first wedge prism 1024 and the second wedge prism 1025 can be right-angled trapezoidal in shape, and these cross-sections are parallel to the optical axis of the wedge prism. The laser incident surface of the first wedge prism 1024 and the laser exit surface of the second wedge prism 1025 can both be perpendicular to the optical axis. The laser exit surface of the first wedge prism 1024 and the laser incident surface of the second wedge prism 1025 are inclined surfaces of the wedge prisms, which are tilted relative to the optical axis. The inclined surfaces in the first wedge prism 1024 and the second wedge prism 1025 are opposite each other. The wedge angle of the first wedge prism 1024 and the wedge angle of the second wedge prism 1025 can be equal. Both the first wedge prism 1024 and the second wedge prism 1025 can be circular optical wedges. In some implementations, the target cross-section of the first wedge prism 1024 and the second wedge prism 1025 may also be an isosceles trapezoid or a trapezoid of other shapes. The wedge angle of the first wedge prism 1024 and the wedge angle of the second wedge prism 1025 may also be unequal, which is not limited here.

[0065] In this embodiment, the relative position of the two wedge prisms can be adjusted by rotating at least one of the first wedge prism 1024 and the second wedge prism 1025. The optical axis of the first wedge prism 1024 and the optical axis of the second wedge prism 1025 can coincide, and the first wedge prism 1024 and / or the second wedge prism 1025 can rotate around their optical axes. Each wedge prism can rotate at any angle in any direction (clockwise or counterclockwise) according to the corresponding requirements. The two wedge prisms can rotate relative to each other or rotate together. In some embodiments, the first wedge prism 1024 and / or the second wedge prism 1025 can also be translated. In some embodiments, the first wedge prism 1024 and the second wedge prism 1025 are connected to a motor, which controls the rotation of the wedge prisms.

[0066] The relative rotation of the first wedge prism 1024 and the second wedge prism 1025, such as keeping one wedge prism fixed while rotating the other, can cause a change in the overall angle between the inclined planes of the two wedge prisms. When the vertices of the two inclined planes are facing each other, the overall angle between the two inclined planes is the largest, allowing for the maximum angle deflection of the passing laser. Here, the vertex of the inclined plane refers to the point on that inclined plane closest to the other wedge prism. By controlling the rotation of one wedge prism, the final deflection angle of the laser can be controlled. The first wedge prism 1024 and the second wedge prism 1025 can rotate together, rotating in the same direction by the same angle, adjusting the deflection direction of the laser, allowing it to be deflected in any direction, such as up, down, left, or right. By combining this relative rotation and joint rotation, both the deflection direction and the deflection angle of the laser can be adjusted. When the wedge angles of the first wedge prism 1024 and the second wedge prism 1025 are equal, the two inclined planes can be rotated to a parallel state. At this time, the laser is not deflected, and the laser can be emitted along the optical axis of the wedge prism.

[0067] For example, for the detection position in the inner wall N of the reaction chamber, the deflection direction and angle relative to the optical axis of the wedge prism can be determined. For instance, the inclined surfaces of the two wedge prisms can be initially aligned parallel. From this state, one wedge prism can be rotated so that the overall angle between the inclined surfaces of the two wedge prisms after rotation satisfies the angle corresponding to the deflection angle. Then, the two wedge prisms can be rotated as a whole to achieve the desired orientation for the deflection direction.

[0068] In the first implementation of this application, the target cross-sections of both wedge prisms are right-angled trapezoids, and the inclined surfaces of the two wedge prisms are opposite each other with equal wedge angles. Thus, by rotating the wedge prisms in different ways, it is possible to ensure that the laser is directed to any position within a circular region, thereby enabling impurity detection at any location within that region.

[0069] In the second implementation of this application, the target cross-section of the wedge prism is not a right trapezoid, or the wedge angles are not equal. In this case, the laser light passing through the two wedge prisms may not be emitted along the optical axis. By rotating the wedge prisms differently, the laser light can be directed to multiple positions within a ring-shaped region. In this case, the required rotation method of the wedge prism for the deflection direction and deflection angle corresponding to the position to be detected differs somewhat from that in the first implementation. The appropriate rotation method can be determined based on the actual structure.

[0070] The embodiments described above all assume that both the first wedge prism 1024 and the second wedge prism 1025 can rotate freely. In some embodiments, only one wedge prism may be rotatable. In this case, only the deflection angle of the laser can be adjusted, allowing the laser to be directed towards multiple positions in one direction on the inner wall of the reaction chamber. In some embodiments, both wedge prisms can rotate together. In this case, only the deflection direction of the laser can be adjusted, allowing the laser to be directed towards multiple directions on the inner wall of the reaction chamber, but the laser deflection angle in each direction is fixed.

[0071] In this embodiment, the optical transmission component 102 consists of two wedge prisms forming a light deflection component. Each wedge prism has a front and rear surfaces with a certain angle between them. When light (i.e., the laser emitted by laser 101) enters the wedge prism, the direction of light propagation is deflected relative to its original direction due to refraction on the surface of the wedge prism. The angle of deflection is related to the refractive index of the wedge prism and the angle between the light and the surface. In this embodiment, the two wedge prisms have the same wedge angle and coaxial optical axes, with their inclined surfaces facing each other. The two wedge prisms can be driven by a motor, and each wedge prism can rotate freely around its optical axis. The two wedge prisms can rotate together around their optical axes. The free rotation of one wedge prism can cause a change in the angle between the inclined surfaces of the two wedge prisms, thus controlling the final deflection angle of the light passing through the wedge prism assembly. The overall rotation of the wedge prism assembly can control the specific direction in which the light is deflected. This ensures that the laser emitted by the laser 101 can be directed to multiple locations on the inner wall N of the reaction chamber, thereby enabling the detection of impurities at multiple points. Based on these impurity detection results, the overall impurity situation on the inner wall N of the reaction chamber can be analyzed, which can improve the overall impurity detection effect on the inner wall N of the reaction chamber.

[0072] It should be noted that, in this embodiment, the optical transmission component 102 is illustrated by including a dichroic mirror 1021, a beam expander 1022, a focusing mirror 1023, and a wedge prism group (a first wedge prism 1024 and a second wedge prism 1025). In some embodiments, the optical transmission component 102 may include only some of these components.

[0073] Due to the wedge prism, the laser can be directed to multiple locations within a region on the inner wall N of the reaction chamber. Correspondingly, the impurity detection system 10 can include discharge electrodes 103 disposed at multiple locations on the inner wall N of the reaction chamber to ensure that regardless of the laser's direction, discharge electrodes 103 are present to enhance the spectral signal corresponding to the plasma, thus guaranteeing the impurity detection effect at that location. For example, the impurity detection system 10 can include discharge electrodes 103 disposed at multiple locations around a target location on the inner wall of the reaction chamber. The target location is the position along which the optical axis of the wedge prism on the inner wall N of the reaction chamber passes, i.e., the position where the laser is directed onto the inner wall N of the reaction chamber along that optical axis.

[0074] In this embodiment, before using the impurity detection system 10 to detect impurities on the inner wall N of the reaction chamber, the pulse power supply can be adjusted to determine the target voltage value required for impurity detection. After adjustment, the pulse power supply is turned off. During impurity detection, the control system can first determine the detection location in the inner wall N of the reaction chamber. This control system can be connected to the impurity detection system 10 to control the components in the impurity detection system 10. In one detection, the control system can set a single detection location or set multiple detection locations simultaneously.

[0075] Then, the impurity detection system 10 can be triggered to operate, energizing the pulse power supply. The laser 101 emits a pulsed laser, and simultaneously, the motor controls the wedge prism assembly to move to the position corresponding to the detection location. At the same time, the spectrometer 105 starts operating. The pulsed laser beam is expanded by the beam expander 1022 and then focused by the focusing lens 1023 before being directed to the dichroic mirror 1021. Through the dichroic mirror 1021, the laser beam reaches the wedge prism assembly. Refraction occurs in the wedge prism assembly, causing the laser focal point to hit the detection location precisely. At this detection location, the material on the inner wall of the reaction chamber is excited to form plasma, which in turn generates a spectral signal.

[0076] After plasma is generated, conductive ions will form between the discharge electrode 103 and the inner wall N of the reaction chamber, creating a conductive bridge. This generates an electric spark that enhances the spectral signal corresponding to the laser-excited plasma and prolongs the spectral decay time. Based on the principle of optical path reversibility, the spectral signal corresponding to the excited and enhanced plasma is transmitted in the reverse direction of laser transmission to the wedge prism group. After refraction by the wedge prism group, it illuminates the dichroic mirror 1021. Reflection occurs on the surface of the dichroic mirror 1021, and the signal reaches the collecting lens 1042. The collecting lens 1042 focuses the collected spectrum and transmits it to the end face of the optical fiber 1041. The optical fiber 1041 transmits the spectral signal to the spectrometer 105. The spectrometer 105 analyzes and processes the collected spectral signal to determine the elemental composition of the inner wall material of the reaction chamber. Through these steps, the elemental composition information of the inner wall material of the reaction chamber can be obtained in real time.

[0077] Compared to traditional LIBS systems, this embodiment modulates the optical path using a set of wedge prisms, enabling real-time online analysis of impurity elements at a wide range of free points on the inner wall of the reaction chamber. This embodiment also utilizes discharge electrodes and spark assistance to enhance the intensity of the spectral signal generated by laser penetration of the inner wall material of the reaction chamber, extending the attenuation time of the spectral lines and effectively improving the intensity and signal-to-noise ratio of the spectral signal received by the optical signal acquisition component. Furthermore, in this embodiment, the laser transmission window and the spectral signal acquisition window are the same window, simplifying the installation structure. Using wedge prisms to deflect the laser eliminates the need to reposition the entire optical path system when acquiring spectral signals at different locations, reducing operational complexity and minimizing requirements on window aperture and other parameters.

[0078] In summary, the impurity detection system for the inner wall surface of a nuclear fusion reactor provided in this application, in addition to generating plasma by laser excitation of the inner wall, also includes electrodes placed on the inner wall and discharging these electrodes to continue ionizing the laser-excited plasma. This increases the intensity of the plasma's spectral signal, thereby prolonging the plasma's duration. This helps the optical signal acquisition component collect a higher intensity and better quality spectral signal, facilitating more accurate impurity detection by the spectrometer based on this spectral signal, thus improving the impurity detection effect.

[0079] This application also provides a fusion reaction system, which includes a nuclear fusion reactor and the aforementioned impurity detection system 10 for the inner wall surface of the nuclear fusion reactor chamber. The discharge electrode 103 in the impurity detection system 10 is disposed on the inner wall of the reactor chamber within the nuclear fusion reactor. The impurity detection system 10 is used to detect impurities on the inner wall surface of the reactor chamber within the nuclear fusion reactor.

[0080] In one embodiment, the fusion reaction system further includes a control system for the impurity detection system 10, used to control the components in the impurity detection system 10.

[0081] In one embodiment, the fusion reaction system further includes a plasma control unit. The plasma control unit can be connected to the impurity detection system 10 and used to control the plasma in the reaction chamber based on the impurity information. For example, parameters such as plasma density, temperature, and shape can be controlled. For instance, operators can operate the plasma control unit to adjust the parameters of the nuclear fusion reactor to control the plasma in the reaction chamber. For example, the voltage transmitted to the magnet in the nuclear fusion reactor can be adjusted via the plasma control unit.

[0082] Figure 5 is a flowchart of an impurity detection method according to an embodiment of this application. This method can be applied to the impurity detection system 10 on the inner wall surface of the nuclear fusion reactor chamber shown in Figure 1 or Figure 2, and can be executed by the control system of the impurity detection system 10. This method can be referred to in conjunction with the foregoing description of the impurity detection system 10. As shown in Figure 5, the method may include the following steps:

[0083] Step 502: Discharge the inner wall of the reaction chamber of the nuclear fusion reactor through the discharge electrode.

[0084] For example, a pulsed voltage can be applied to the discharge electrode using a pulsed power supply, causing the discharge electrode to discharge into the inner wall of the reaction chamber of the nuclear fusion reactor. In one embodiment, step 502 may include: applying a pulsed voltage between the discharge electrode and the inner wall of the reaction chamber of the nuclear fusion reactor based on a target voltage value using a pulsed power supply, causing the discharge electrode to discharge into the inner wall of the reaction chamber. The target voltage value is less than a voltage threshold value, which is the voltage value required to generate an electric spark between the discharge electrode and the inner wall of the reaction chamber.

[0085] For example, before step 502, the pulse power supply can be adjusted to determine a voltage threshold, and a target voltage value can be determined based on this threshold. The target voltage value can be obtained by subtracting a specific voltage value from the threshold. The discharge electrode discharges to the inner wall of the reaction chamber of the nuclear fusion reactor based on this target voltage value, without generating an electric spark, thus avoiding interference with the laser-excited plasma.

[0086] Step 504: A laser is emitted through a laser, which is directed through an optical transmission component to the area where the discharge electrode is located on the inner wall of the reaction chamber, thereby exciting the generation of plasma on the inner wall of the reaction chamber, and the voltage on the discharge electrode continues to ionize the plasma.

[0087] In some embodiments, prior to step 504 (such as prior to step 502), the method further includes: adjusting the poses of the first wedge prism and the second wedge prism based on the prism poses corresponding to the position to be detected in the inner wall of the reaction chamber.

[0088] For example, the control system can first determine the location to be detected in the inner wall of the reaction chamber, and calculate the deflection direction and angle that the laser should have to reach that location. This deflection direction and angle are then converted into the poses of the first and second wedge prisms according to a set relationship. Based on these poses, the first and second wedge prisms can be controlled to rotate accordingly, assuming each wedge prism is in a specific pose. For instance, a motor can be controlled to rotate the first and second wedge prisms.

[0089] Step 506: Acquire the spectral signal corresponding to the plasma through the optical signal acquisition component and transmit the spectral signal to the spectrometer.

[0090] Step 508: Analyze the spectral signal using a spectrometer to obtain information on impurities on the inner wall surface of the reaction chamber.

[0091] In one embodiment, after step 508, the method may further include: outputting impurity information to the plasma control unit so that the plasma control unit can control the plasma in the reaction chamber based on the impurity information. For details on this step, please refer to the foregoing description of fusion reaction systems; it will not be repeated here.

[0092] In summary, the impurity detection method for the inner wall surface of a nuclear fusion reactor provided in this application involves discharging a laser through a discharge electrode onto the inner wall of the reactor chamber, emitting a laser beam through a laser source, and directing the laser beam through an optical transmission component to the area where the discharge electrode is located on the inner wall of the reactor chamber. This excites the generation of plasma on the inner wall of the reactor chamber, and the voltage on the discharge electrode continues to ionize the plasma. This can increase the intensity of the plasma's spectral signal, thereby prolonging the plasma's duration. It also helps the optical signal acquisition component to acquire a higher intensity and better quality spectral signal, facilitating more accurate impurity detection by the spectrometer based on this spectral signal, thus improving the impurity detection effect.

[0093] The foregoing has described specific embodiments of this application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0094] Those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to this application. In the above embodiments, the descriptions of each embodiment have different focuses, and for parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0095] The preferred embodiments disclosed above are merely illustrative of this application. The optional embodiments do not exhaustively describe all details, nor do they limit this application to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this application. These embodiments are selected and specifically described in this application to better explain the principles and practical applications of this application, thereby enabling those skilled in the art to better understand and utilize this application.

Claims

1. A system for detecting impurities on the inner wall surface of a nuclear fusion reactor chamber, comprising: Laser, optical transmission components, discharge electrodes, optical signal acquisition components, and spectrometer, among which, The discharge electrode is located on the inner wall of the reaction chamber of the nuclear fusion reactor. The laser is configured to emit a laser beam, which is directed through the optical transmission assembly toward the region where the discharge electrode is located on the inner wall of the reaction chamber, thereby exciting the inner wall of the reaction chamber to generate plasma. The discharge electrode is configured to discharge toward the inner wall of the reaction chamber, ionizing the plasma; The optical signal acquisition component is configured to acquire the spectral signal corresponding to the plasma and transmit the spectral signal to the spectrometer; and The spectrometer is configured to analyze the spectral signal to obtain impurity information on the surface of the inner wall of the reaction chamber.

2. The impurity detection system of claim 1 further includes a pulse power supply configured to apply a pulse voltage between the discharge electrode and the inner wall of the reaction chamber, the discharge electrode being used to ionize the plasma based on the pulse voltage.

3. The impurity detection system according to claim 1, wherein, The optical transmission component includes a first wedge prism and a second wedge prism, and the laser beam is directed toward the inner wall of the reaction chamber via the first and second wedge prisms in sequence; and The optical axis of the first wedge prism coincides with the optical axis of the second wedge prism, and the first wedge prism and / or the second wedge prism can rotate around the optical axis.

4. The impurity detection system according to claim 3, wherein, The laser incident surface of the first wedge prism and the laser exit surface of the second wedge prism are both perpendicular to the optical axis, and the laser exit surface of the first wedge prism and the laser incident surface of the second wedge prism are inclined surfaces; and / or, the wedge angle of the first wedge prism is equal to the wedge angle of the second wedge prism.

5. The impurity detection system according to claim 3 or 4, comprising the discharge electrode disposed at a plurality of locations around a target location on the inner wall of the reaction chamber, wherein the target location is the location through which the optical axis passes on the inner wall of the reaction chamber.

6. The impurity detection system according to any one of claims 1 to 3, wherein, The optical transmission component includes a beam expander configured to collimate and expand the incident laser beam; or... The optical transmission assembly includes a focusing lens configured to focus the incident laser light, and the inner wall of the reaction chamber is located at the focal point of the focusing lens; or... The optical transmission component includes a beam expander and a focusing lens, and the laser beam passes through the beam expander and the focusing lens in sequence before being directed toward the inner wall of the reaction chamber.

7. The impurity detection system according to any one of claims 1 to 3, wherein, The optical transmission component includes a dichroic mirror, which transmits the laser light and reflects the spectral signal corresponding to the plasma; and The laser and the optical signal acquisition component are located on opposite sides of the dichroic mirror, and the spectral signal is reflected back to the optical signal acquisition component after being incident on the dichroic mirror.

8. An impurity detection method, applied to the impurity detection system on the inner wall surface of a nuclear fusion reactor chamber as described in any one of claims 1 to 7, wherein, The method includes: Discharge is applied to the inner wall of the reaction chamber of the nuclear fusion reactor through discharge electrodes; A laser is emitted by a laser, which is directed through an optical transmission component to the area where the discharge electrode is located on the inner wall of the reaction chamber, thereby exciting the inner wall of the reaction chamber to generate plasma, and the voltage on the discharge electrode continues to ionize the plasma; The optical signal acquisition component acquires the spectral signal corresponding to the plasma and transmits the spectral signal to the spectrometer; and The spectral signal is analyzed by the spectrometer to obtain impurity information on the inner wall surface of the reaction chamber.

9. The method according to claim 8, wherein, The discharge through the discharge electrode to the inner wall of the reaction chamber of the nuclear fusion reactor includes: The pulsed power supply applies a pulsed voltage between the discharge electrode and the inner wall of the reaction chamber of the nuclear fusion reactor based on a target voltage value, causing the discharge electrode to discharge to the inner wall of the reaction chamber; wherein the target voltage value is less than a voltage threshold value, the voltage threshold value being the voltage value that generates an electric spark between the discharge electrode and the inner wall of the reaction chamber.

10. The method according to claim 8 or 9, wherein, The optical transmission assembly includes a first wedge prism and a second wedge prism; before emitting laser light through the laser, the method further includes: Based on the prism pose corresponding to the position to be detected in the inner wall of the reaction chamber, the poses of the first wedge prism and the second wedge prism are adjusted.

11. A fusion reaction system, comprising: Nuclear fusion reactor; and The impurity detection system for the inner wall surface of a nuclear fusion reactor chamber according to any one of claims 1 to 7, wherein, The discharge electrode in the impurity detection system is disposed on the inner wall of the reaction chamber in the nuclear fusion reactor, and the impurity detection system is configured to detect impurity information on the surface of the inner wall of the reaction chamber in the nuclear fusion reactor.

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