CN-121983356-A - Fuel stagnation in-situ nondestructive diagnostic system and method for high-heat-load plasma superconducting linear device wall material

CN121983356ACN 121983356 ACN121983356 ACN 121983356ACN-121983356-A

Abstract

The invention discloses a fuel retention in-situ nondestructive diagnosis system and method for a high-heat-load plasma superconducting linear device wall material, and belongs to the technical field of magnetic confinement controllable thermonuclear fusion. The system is arranged on a high-heat load plasma superconducting linear device and acts on a sample arranged on the high-heat load plasma superconducting linear device, a long pulse laser induction unit is used for generating long pulse laser with a pulse width in millisecond magnitude, a spectrum detection unit is used for collecting characteristic spectrum signals excited to radiate after desorption fuel gas enters main plasma, and a magnetic field collaborative diagnosis unit is used for establishing corresponding relations between laser parameters and spectrum acquisition parameters required for obtaining optimal diagnosis signals under different magnetic field intensity conditions based on experimental calibration. The feasibility of LIDS under a strong magnetic field is verified and established, the difficult problems of removal and quantitative analysis of fuel gas which is insufficiently transported and combusted in the magnetic field and is retained in wall materials are solved, and a complete scheme capable of online and nondestructive diagnosis of first wall fuel retention is provided.

Inventors

XIAO QINGMEI
WANG YIQIN
LIU YANG
NIE QIUYUE
HE YANKANG
Wei Zhelong

Assignees

哈尔滨工业大学

Dates

Publication Date: 20260505
Application Date: 20260126

Claims (10)

1. The fuel stagnation in-situ nondestructive diagnosis system for the wall material of the high-heat-load plasma superconducting linear device is characterized in that the fuel stagnation in-situ nondestructive diagnosis system is arranged on the high-heat-load plasma superconducting linear device and acts on a sample arranged on the high-heat-load plasma superconducting linear device; the fuel retention in-situ nondestructive diagnosis system comprises a long pulse laser induction unit, a spectrum detection unit and a magnetic field cooperative diagnosis unit; The long pulse laser induction unit is used for generating long pulse laser with pulse width in millisecond level; The spectrum detection unit is used for collecting characteristic spectrum signals which are excited and radiated after desorption fuel gas enters the main plasma; the magnetic field collaborative diagnosis unit establishes the corresponding relation between the laser parameters and the spectrum acquisition parameters required for obtaining the optimal diagnosis signals under the condition of different magnetic field intensities based on experimental calibration.
2. A fuel stagnation in-situ non-destructive diagnostic method for a wall material of a high thermal load plasma superconducting linear device using the fuel stagnation in-situ non-destructive diagnostic system for a wall material of a high thermal load plasma superconducting linear device of claim 1, the fuel stagnation in-situ non-destructive diagnostic method comprising environmental adaptive calibration and field diagnostic applications: the environment adaptability calibration is carried out on an experimental platform with an adjustable magnetic field, a mapping relation model of 'magnetic field intensity-optimized diagnosis parameters' is established, and finally a mapping library is formed; the field diagnosis application is carried out in the actual strong magnetic field environment of the target thermal load plasma superconducting linear device, and the diagnosis operation is guided by using a mapping library established by environment adaptability calibration.
3. The fuel stagnation in situ non-destructive diagnostic method according to claim 2, wherein said environmentally adaptive calibration is in particular, S1, selecting a material sample which is the same as the wall material of the target thermal load plasma superconducting linear device; step S2, under the premise of ensuring that the laser energy density does not cause material damage, systematically changing laser operation parameters under a plurality of different preset magnetic field intensities; S3, performing laser-induced desorption operation on each group of magnetic field-laser parameter combinations, and synchronously collecting generated fuel characteristic spectrum signals; And S4, analyzing all acquired spectrum signals, evaluating signal to noise ratio or signal intensity, identifying and recording laser parameter combinations capable of optimizing the quality of the diagnosis signals for each magnetic field intensity, and forming an 'optimizing parameter mapping library' by the optimal parameter combinations and the corresponding magnetic field intensities.
4. The method of claim 3, wherein the optimized parameter map library further comprises optimal signal acquisition delay time information for different magnetic field strengths; And in the environment adaptability calibration, the surface morphology of the material after laser irradiation can be synchronously monitored and recorded, and auxiliary 'parameter-surface state' associated data is established for verifying the nondestructive performance of the diagnosis process after the second stage.
5. The method for in-situ nondestructive diagnosis of fuel stagnation according to claim 3, wherein the step S1 is specifically that the long pulse laser induction unit is started under the condition that the high heat load plasma superconducting linear device maintains plasma discharge or background plasma, and laser pulses with energy density controlled below a nondestructive threshold are irradiated to a designated position of a sample; the step S2 is specifically that laser energy thermally desorbs the wall material and the fuel gas retained on the near surface, and the desorbed gas is transported along the direction of magnetic force lines in a strong magnetic field environment and enters a main plasma region; the step S3 is specifically that desorbed gas particles are excited and ionized in main plasma, and the characteristic spectrum is radiated; The spectral signal radiated in step S3 is collected by the spectral detection unit.
6. The method of in situ non-destructive diagnosis of fuel retention according to claim 3, wherein said in situ diagnostic application is in particular, Step X1, determining or measuring the magnetic field intensity of a diagnosis area of the current high-heat-load plasma superconducting linear device; step X2, inquiring the 'optimizing parameter mapping library' obtained in the step S4 according to the magnetic field intensity to obtain corresponding optimizing laser parameters; x3, performing laser-induced desorption operation on the region to be diagnosed of the high-heat-load plasma superconducting linear device wall material by using the optimized laser parameters; And X4, acquiring a characteristic spectrum of the radiation of the excited desorption gas by utilizing the existing spectrum diagnosis system of the high-heat-load plasma superconducting linear device, and evaluating the fuel retention condition according to the signal.
7. The method according to claim 6, wherein the step X4 is specifically to call a magnetic field-diagnostic parameter optimization database or model matching the current device magnetic field strength, analyze and interpret the collected spectrum signal, and evaluate the fuel retention level at the diagnostic point.
8. The method of in situ non-destructive diagnosis of fuel retention according to claim 7, wherein the determination of whether the diagnosis is in the non-destructive operating regime is performed by analyzing the signal strength and signal to noise ratio in combination with laser parameters.
9. The in-situ nondestructive diagnostic method of fuel retention according to claim 1, further comprising monitoring laser irradiation points by auxiliary diagnostic means to confirm that the wall material surface is free of signs of damage such as melting, splashing, etc., thereby doubly verifying the nondestructive nature of the diagnosis.
10. The method of in situ non-destructive diagnosis of fuel retention according to claim 1, wherein the optimization database or model is built up by a pre-calibration experiment comprising systematically varying the laser energy density and spot size over similar wall materials under different intensity magnetic fields, finding a laser parameter window that both generates a detectable spectral signal and ensures a non-damaging surface of the material under each magnetic field condition, and storing the optimal parameter combination in association with the corresponding spectral signal feature.

Description

Fuel stagnation in-situ nondestructive diagnostic system and method for high-heat-load plasma superconducting linear device wall material Technical Field The invention belongs to the technical field of magnetic confinement controllable thermonuclear fusion, and particularly relates to a fuel retention in-situ nondestructive diagnosis system and method for a wall material of a high-heat-load plasma superconducting linear device. Background In magnetically confined nuclear high thermal load plasma superconducting devices (e.g., tokamak, linear plasma devices), fuel (deuterium, tritium) hold-up in the plasma-facing material is one of the core parameters affecting the safe operation of the device (especially tritium inventory control) and the plasma performance (e.g., particle recycling). Therefore, it is important to develop techniques that enable in situ, on-line diagnostics of fuel hold-up. Laser Induced Desorption Spectroscopy (LIDS) is a promising in situ diagnostic protocol. The basic principle is that the surface of the wall material is heated by pulse laser to make the retained fuel gas heated and desorbed, the desorbed gas enters the main plasma area of the device, is excited, ionized and radiates a spectrum with element characteristics, and the qualitative and even quantitative evaluation of the fuel retention can be realized by detecting and analyzing the spectrum signal. Theoretically, the method can realize nondestructive diagnosis by precisely controlling the laser energy density to be lower than the damage threshold of the material. However, the technology moves from theory to reliable application in real high thermal load plasma devices, facing a fundamental, unresolved scientific and technical challenge of systematic impact of strong magnetic fields in magnetically confined fusion environments on laser induced desorption processes. The key feature of tokamak devices is their strong confining magnetic field (typically on the order of 1 to 10 tesla). Few studies have been conducted on LIDS, and similar Laser Induced Breakdown Spectroscopy (LIBS) experiments have been conducted under ideal laboratory conditions without or with low magnetic fields. Diagnostic models, signal interpretation methods and parameter optimization experience built under such conditions are likely to fail entirely in high magnetic field environments. This is because the strong magnetic field can significantly alter the motion trajectory of the desorbed gas particles (causing them to make a swirling motion along the magnetic lines of force), affect their transport efficiency from the material surface to the main plasma region, alter their excitation and ionization kinetics in the plasma, and ultimately lead to unpredictable changes in the intensity, signal-to-noise ratio, and time evolution characteristics of the acquired spectroscopic signals. Without a deep understanding and overcoming the effects of magnetic fields, the accuracy, reliability and even feasibility of spectral diagnostics (LIDS) are not guaranteed. To address this challenge, systematic research and validation of methodology must be performed on an experimental platform that is capable of simulating both fusion reactor extreme heat flow and high magnetic field environments. Conventional laboratory equipment cannot provide such a coupling environment. However, high parameter, high heat flux, high magnetic field linear superconducting magnet based plasma devices (e.g., HIT-PSI devices) are capable of generating plasma heat flux densities and magnetic field strengths close to those of future fusion reactor divertor regions, an effective and reliable platform for validating and developing such advanced in situ diagnostic techniques. The basic research of application is developed on the platform, and the basic research is a necessary bridge for connecting laboratory principle verification and future fusion reactor engineering application. In view of the foregoing, there is a need to develop a systematic laser-induced desorption diagnostic methodology that is verified by high-intensity magnetic field environmental experiments. The present invention has been made to solve these problems, as to how to select and optimize laser parameters under strong magnetic fields to obtain optimal diagnostic signals, how the magnetic fields affect the diagnostic process, how to ensure the effectiveness of the diagnosis and the non-destructive nature of the material. Disclosure of Invention The invention provides a fuel retention in-situ nondestructive diagnosis device and method for a high-heat-load plasma superconducting linear device wall material, which are used for verifying and determining the feasibility of LIDS under a strong magnetic field, solving the difficult problems of removal and quantitative analysis of fuel gas which is insufficiently transported and combusted in the magnetic field and remains in the wall material, and providing a complete scheme capable of perform