Fusion reactor pipe and control system integrated composite shielding system

Abstract

The application belongs to the technical field of electromagnetic compatibility and radiation protection of magnetic confinement nuclear fusion reactors, and discloses a fusion reactor pipeline and control system integrated composite shielding system. The composite shielding system comprises an NBI / ECRH hall full-configuration shielding unit, a lithium-lead loop room simplified version shielding unit and a wall-penetrating shielding connecting assembly. The application solves the fundamental contradiction between "shielding stray field and not disturbing the main field" from the physical principle, adopts a hierarchical shielding design concept, and adopts differential configuration for different residual interference intensities at the positions where the pipelines and cables penetrate the NBI / ECRH hall, the lithium-lead loop room and the wall, so as to comprehensively meet the electromagnetic compatibility technical requirements of the fusion reactor, the national standard GB / T 17626.8 and the on-site working condition requirements, and adapt to the special working conditions of the fusion reactor, such as low activation and high temperature resistance.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic compatibility and radiation protection technology for magnetic confinement nuclear fusion reactors, and particularly relates to an integrated composite shielding system for fusion reactor pipelines and control systems. Background Technology

[0002] Magnetic confinement fusion reactors operate in extremely strong magnetic field environments, with the central magnetic field generated by the main unit's circumferential and poloidal field coils reaching over 4T. Liquid lithium-lead, used as both the cladding coolant and tritium breeder, faces severe threats to the safe and stable operation of the system from multi-source composite electromagnetic interference during its circulation within the loop. These interferences are mainly as follows: A 50mT DC stray magnetic field is generated by leakage flux from the main magnet, poloidal coil current, and plasma current, and is distributed in the pipe, valve, and instrumentation areas of the cladding loop. According to magnetohydrodynamics (MHD) theory, stray magnetic fields cause additional MHD pressure drops in lithium-lead flow. Under a 50mT magnetic field, the MHD pressure drop in a DN50 pipe can reach over 0.5MPa, significantly increasing the load on the circulating pump. Simultaneously, stray magnetic fields interfere with the normal operation of precision instruments such as pressure transmitters and flow meters, leading to measurement errors exceeding 10%.

[0003] Broadband electromagnetic interference: High-power microwaves generated by auxiliary heating systems such as electron cyclotron resonance heating (ECRH, not less than 170 GHz) and low-hybrid current drive (LHCD, not less than 3 GHz), as well as transient electromagnetic pulses generated when plasma breaks, can enter the control system of lithium-lead circuit through radiation and conduction coupling, causing serious accidents such as valve malfunction and data acquisition system crash.

[0004] The NBI system is characterized by strong interference: the neutral beam injection system, as the main auxiliary heating method for fusion reactors, employs a three-electrode structure (plasma electrode - suppression electrode - extraction electrode), operating at an accelerating voltage of 120 kV and a maximum operating temperature of 70 A / D. + Under conditions of beam current density of 200mA / cm² and a long pulse of 1000s, three types of interference will be generated: transient high-voltage electromagnetic pulse, hard X-ray radiation, and strong pulsed magnetic field.

[0005] On-site interference attenuation characteristics: The NBI and ECRH systems are approximately 10 meters away from the lithium-lead loop room, separated by a reinforced concrete wall approximately 1 meter thick (reference). Figure 5(As shown). According to the calculation results of the electromagnetic shielding test standard for nuclear industry buildings (EJ / T 1151-2002), the attenuation characteristics of the wall for interference of different frequency bands are as follows: (1) For 10~100keV hard X-rays: attenuation rate ≥99.999%, X-ray dose rate in the lithium-lead circuit room <1μGy / h, far below the safety limit; (2) For 170GHz millimeter-wave microwaves: attenuation rate ≥60dB, direct radiation is almost completely blocked; (3) For transient electromagnetic pulses with a rise time of 10ns: after attenuation by the wall, the residual electric field strength in the lithium-lead circuit room is ≤1kV / m; (4) For low-frequency magnetic fields of 50Hz~10kHz: attenuation rate is only 3~5dB, and the residual pulse magnetic field strength can reach 40mT. However, electromagnetic interference can still couple into the lithium-lead circuit room through cable trenches, pipe penetration holes and other paths in the reinforced concrete wall, and the residual interference intensity is still sufficient to cause instrument measurement errors and control system malfunctions.

[0006] Furthermore, the control system cabinets within the fusion reactor main hall face stringent electromagnetic compatibility (EMC) requirements. Simultaneously, the control system cabinets located in this area (NBI, ERCH, LHCD rooms, and lithium-lead alloy circuit rooms) must also meet EMC requirements: shielding effectiveness ≥40dB in the 30MHz~230MHz frequency band and ≥30dB in the 30MHz~1000MHz frequency band. According to the national standard GB / T 17626.8-2022 "Electromagnetic Compatibility Testing and Measurement Technology - Power Frequency Magnetic Field Immunity Test," the equipment in the tokamak bio-shielded wall window equipment room (within the portcell) (NBI, ERCH, LHCD rooms, and lithium-lead alloy circuit rooms are located in this area) must withstand a stable power frequency magnetic field of 60A / m and a short-time power frequency magnetic field immunity of 200A / m.

[0007] Existing electromagnetic shielding technologies cannot simultaneously meet all the above requirements and have the following inherent drawbacks that cannot be overcome: I. Traditional ferromagnetic shielding (silicon steel, permalloy): Although it has a good shielding effect against DC magnetic fields, it remains unsaturated in a strong magnetic field of at least 4T on the host, which will severely distort the magnetic field distribution of the host and lead to plasma confinement failure. According to the ITER design documents, the relative distortion ΔB / B of the local magnetic field introduced by components near the cladding region should be ≤0.01%. A 1mm thick silicon steel sheet has already caused a local magnetic field distortion of more than 1.2% in a 5T magnetic field, which is far beyond the standard. This data is a simulation comparison value of shielding structures of the same size. In actual applications, silicon steel sheets are usually used in multi-layer stacked structures, which will slightly reduce the distortion rate, but it still far exceeds the 0.01% tolerance.

[0008] II. Steel plate / copper mesh shielded cabinets: These can only shield high-frequency electromagnetic interference, and cannot shield DC stray magnetic fields or power frequency magnetic fields at all; moreover, steel plates and copper meshes will produce long-half-life activation products (such as...) under fusion neutron irradiation.60 Co、 64 Cu), which does not meet the requirements for low activation.

[0009] 3. Single ferrite shielding: Although ferrite has a low saturation magnetic flux density and can saturate under strong fields, a single structure cannot simultaneously meet the requirements of DC magnetic shielding and high-frequency electromagnetic shielding; moreover, it does not solve the problem of the shielding layer's induced current disturbing the host's magnetic field, and will generate an additional reverse magnetic field when the plasma current changes rapidly.

[0010] IV. Silicon carbide ceramic shielding: It has excellent low activation and high temperature resistance, but it does not have DC magnetic shielding capability at all and can only shield some high-frequency electromagnetic interference.

[0011] Therefore, there is an urgent need to develop an integrated shielding system that can simultaneously achieve "multi-band electromagnetic shielding + no disturbance to the host's magnetic field + economical hierarchical configuration". Summary of the Invention

[0012] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, one objective of this invention is to propose an integrated composite shielding system for fusion reactor piping and control systems. This system addresses the fundamental contradiction between "shielding stray fields and not disturbing the main field" from a physical perspective. It employs a graded shielding design concept, using differentiated configurations for varying residual interference intensities at locations on the walls and walls where piping and cables pass through, including the NBI / ECRH lobby and lithium-lead loop rooms. This comprehensively meets the electromagnetic compatibility requirements of the fusion reactor, the GB / T 17626.8 national standard, and on-site operating conditions, adapting to the special operating conditions of fusion reactors, which require low activation and high temperatures.

[0013] According to an embodiment of the present invention, an integrated composite shielding system for fusion reactor piping and control system includes a fully configured shielding unit for the NBI / ECRH hall, a simplified shielding unit for the lithium-lead loop room, and a through-wall shielding connection assembly. The fully configured shielding unit for the NBI / ECRH hall, the simplified shielding unit for the lithium-lead loop room, and the through-wall shielding connection assembly all have a three-layer basic shielding structure fitted over the piping. The three-layer basic shielding structure, from the inside out, consists of an inner high-conductivity shielding layer, a middle selective saturation magnetic shielding layer, and an outer high-conductivity shielding layer. The inner high-conductivity shielding layer faces the protected equipment and is used to shield against high-frequency microwave and transient electric field interference. The middle selective saturation magnetic shielding layer is the only functional layer for DC, power frequency, and pulsed magnetic shielding. The outer high-conductivity shielding layer faces the host magnetic field side and is used to shield against externally incident high-frequency electromagnetic interference, while simultaneously suppressing edge leakage magnetic flux of the middle selective saturation magnetic shielding layer. The NBI / ECRH hall full-configuration shielding unit also includes a low-activation tungsten radiation shielding layer added to the outer periphery of the outer high-conductivity shielding layer of the three-layer basic shielding structure. The low-activation tungsten radiation shielding layer is used to shield the hard X-ray radiation generated by NBI. The NBI / ECRH hall full-configuration shielding unit is suitable for beam pipes and control system cabinets in the NBI / ECRH hall. The simplified shielding unit for lithium-lead circuit rooms uses only the three-layer basic shielding structure and is suitable for pipes and control system cabinets in lithium-lead circuit rooms. The through-wall shielding connection assembly also includes a through-wall shielding sleeve and a shielding gland fitted on the outer periphery of the three-layer basic shielding structure. The through-wall shielding connection assembly is used to achieve electromagnetic shielding continuity when pipes and cables pass through walls.

[0014] Compared with existing technologies, the integrated composite shielding system for fusion reactor piping and control systems of this invention has the following significant advantages: I. This invention resolves the fundamental contradiction between "shielding stray fields and not disturbing the main field" from a physical perspective: It pioneers the selective saturation magnetic shielding principle, utilizing the differentiated magnetic properties of the intermediate selective saturation magnetic shielding layer under different magnetic field intensities—deeply saturated in a 4T strong field with incremental permeability approaching vacuum, and unsaturated in a 50mT weak field with permeability reaching thousands—achieving an adaptive function that avoids disturbing the main magnetic field in strong field regions and efficiently shields stray magnetic fields in weak field regions. COMSOL multiphysics simulation results show that, under a 4T background magnetic field, the local magnetic field distortion ΔB / B introduced by the shielding structure of this invention is ≤0.005%, fully meeting the ITER requirement of ≤0.01% tolerance; while the distortion introduced by a silicon steel shielding layer of the same size exceeds 1.2%, far exceeding the standard. In a weak field region without strong field bias, the shielding effectiveness against a 50mT stray magnetic field is ≥23dB, reducing the MHD voltage drop by more than 90%.

[0015] II. Fully Meets the Requirements for All Operating Conditions and Regional Interference of Fusion Reactors: It is currently the only shielding solution that simultaneously meets the electromagnetic compatibility technical requirements of fusion reactors, the GB / T 17626.8 national standard, and the regional interference characteristics of fusion reactor sites, without requiring additional independent power frequency magnetic field shielding devices. It effectively shields against 50mT DC stray magnetic fields, 50Hz power frequency magnetic fields, NBI transient electromagnetic pulses, 1GHz~170GHz high-frequency microwaves, and hard X-rays.

[0016] III. Graded shielding design with excellent economic efficiency: Differentiated shielding configurations are adopted according to the actual interference intensity of different areas. The lithium-lead loop room adopts a simplified version of the three-layer basic shielding structure, eliminating the low-activation tungsten radiation shielding layer. The intermediate selective saturation magnetic shielding layer can be optimized to about 5mm, reducing costs and weight, and achieving the best cost performance while ensuring safety.

[0017] Fourth, it achieves full-link system-level electromagnetic protection: For the first time, the shielding of liquid metal loop pipeline, NBI beam pipeline, control system cabinet, and through-wall connection shielding are unified into the same technical architecture, which completely eliminates the hidden danger of electromagnetic interference coupling into the control system through through-wall holes, cable trenches, etc., and greatly improves the overall reliability of the system.

[0018] V. Excellent Low Activation and High Temperature Resistance: The shielding structure of this invention exhibits a short half-life of the main activation products generated under fusion neutron irradiation, with no... 60 Co-type long-half-life, high-activity nuclides exist, with only trace amounts of long-half-life, low-activity nuclides present, which meets the requirements for low-activation waste management in fusion reactors and is beneficial for radioactive waste management during reactor decommissioning; with a reliable anti-oxidation coating, it can withstand a high-temperature environment of 600°C for a long time, meeting the operating temperature requirements of lithium-lead loops and NBI systems.

[0019] VI. The structure is reliable and the installation and maintenance are convenient.

[0020] In summary, the integrated composite shielding system for fusion reactor piping and control systems of this invention resolves the fundamental contradiction between "shielding stray fields and not disturbing the main field" from a physical perspective. It adopts a graded shielding design concept, employing differentiated configurations for varying residual interference intensities at locations on the walls where pipelines and cables pass through, including the NBI / ECRH lobby and lithium-lead loop rooms. This comprehensively meets the electromagnetic compatibility requirements of the fusion reactor, the GB / T 17626.8 national standard, and on-site operating conditions, and is suitable for the special operating conditions of fusion reactors, such as low activation and high temperature resistance. The integrated composite shielding system for fusion reactor piping and control systems of this invention is particularly suitable for electromagnetic protection of liquid metal cladding loops and auxiliary heating systems.

[0021] In some embodiments, both the inner high-conductivity shielding layer and the outer high-conductivity shielding layer are integral continuous cylindrical structures made of pure molybdenum foil, with a thickness of 0.4~0.6mm.

[0022] In some embodiments, the intermediate selective saturation magnetic shielding layer is made of low-activation manganese-zinc ferrite tiles spliced ​​together; the thickness of the intermediate selective saturation magnetic shielding layer in the fully configured shielding unit of the NBI / ECRH hall is 5~6mm, and the thickness of the intermediate selective saturation magnetic shielding layer in the simplified shielding unit of the lithium-lead loop room is 5~5.5mm.

[0023] In some embodiments, the intermediate selective saturation magnetic shielding layer has axially uniformly distributed narrow slits, the width of which is 0.1~0.2mm.

[0024] In some embodiments, the low-activation manganese-zinc ferrite tile is bonded to the inner high-conductivity shielding layer using a high-temperature resistant inorganic adhesive.

[0025] In some embodiments, the low-activation tungsten radiation shielding layer uses a 1-2 mm thick low-activation tungsten foil to shield against 10-100 keV hard X-ray radiation generated by NBI.

[0026] In some embodiments, the integrated composite shielding system for the fusion reactor pipeline and control system is designed in segments along the axial direction to form several shielding segments. The inner highly conductive shielding layers of adjacent shielding segments are insulated from each other and overlapped. The outer highly conductive shielding layers of adjacent shielding segments are insulated from each other and overlapped.

[0027] In one embodiment, alumina ceramic gaskets are used to insulate the overlapping areas of the inner highly conductive shielding layers of adjacent shielding sections and the overlapping areas of the outer highly conductive shielding layers of adjacent shielding sections, with an insulation resistance ≥10 Ω·cm. 12 Ω.

[0028] In some embodiments, the width of the overlap area of ​​the inner highly conductive shielding layer of adjacent shielding segments is 9-11 mm, and the width of the overlap area of ​​the outer highly conductive shielding layer of adjacent shielding segments is 14-16 mm.

[0029] In some embodiments, the joint between the shielding section installed in the control system cabinet in the NBI / ECRH lobby and the control system cabinet in the lithium-lead circuit room and the adjacent shielding section installed in the pipeline is bent and overlapped, with the overlap area width ≥ 20mm.

[0030] In some embodiments, the observation window on the shielding section of the control system cabinet housed in the NBI / ECRH lobby is made of molybdenum-plated lead glass; the observation window on the shielding section of the control system cabinet housed in the aluminum-lead circuit room is made of molybdenum-plated glass; the ventilation openings of the shielding sections of the control system cabinet housed in the NBI / ECRH lobby and the control system cabinet housed in the lithium-lead circuit room are made of honeycomb molybdenum plates with a shielding effectiveness ≥35dB; the cabinet inlet of the shielding section of the control system cabinet housed in the NBI / ECRH lobby and the control system cabinet housed in the lithium-lead circuit room is made of molybdenum shielded glands.

[0031] In some embodiments, the molybdenum shielded gland has multiple layers of beryllium copper spring fingers inside, which make 360° low-impedance contact with the cable shielding layer; for magnetically sensitive cables, an annular low-activation manganese-zinc ferrite magnetic ring is added inside the molybdenum shielded gland.

[0032] In some embodiments, the structure of the through-wall shielding sleeve is the same as that of the three-layer basic shielding structure. The through-wall shielding sleeve passes through the wall and extends 90-100mm from the wall at both ends. The two ends of the through-wall shielding sleeve are uniformly overlapped with the wall steel mesh and the pipe shielding layer by molybdenum foil at 360°, with an overlap width ≥50mm.

[0033] In some embodiments, a 12-18mm annular gap is reserved between the three-layer basic shielding structure and the pipe, and the annular gap is filled with alumina fiber thermal insulation material.

[0034] In some embodiments, the three-layer basic shielding structure is supported by alumina ceramic support blocks that are evenly distributed circumferentially between the pipe and the structure.

[0035] In some embodiments, each shielding segment is connected to the public grounding reference plane of the hall through multiple grounding electrodes at multiple points, with a grounding resistance ≤0.5Ω; two low-activation manganese-zinc ferrite magnetic rings are connected in series near each grounding electrode close to the shielding segment.

[0036] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the integrated composite shielding system for fusion reactor piping and control systems applicable to the NBI / ECRH hall, according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the integrated composite shielding system for fusion reactor piping and control system in a lithium-lead loop room according to an embodiment of the present invention; Figure 3This is a schematic diagram of the integrated composite shielding system for fusion reactor piping and control system applicable to through-wall applications, according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the overlapping structure between adjacent shielding sections in an integrated composite shielding system for fusion reactor piping and control systems in a lithium-lead loop room, according to an embodiment of the present invention. Figure 5 This is a schematic diagram showing the distribution of the NBI / ECRH lobby and lithium-lead loop rooms.

[0038] Figure Labels Integrated composite shielding system for fusion reactor piping and control system 1000; Fully configured shielding unit for NBI / ECRH lobby 100; Simplified shielding unit for lithium-lead loop room 200; Through-wall shielding connection assembly 300; Pipe 1; Three-layer basic shielding structure 2; Inner high conductivity shielding layer 201; Middle selective saturated magnetic shielding layer 202; Low activation manganese-zinc ferrite tile 2021; Outer high conductivity shielding layer 203; Alumina ceramic gasket 204; Low activation tungsten radiation shielding layer 3; Through-wall shielding sleeve 4; Alumina fiber thermal insulation material 5; Alumina ceramic support block 6; Grounding electrode 7; Low activation manganese-zinc ferrite magnetic ring 8. Detailed Implementation

[0039] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0040] The following is combined with Figures 1 to 4 This invention describes an integrated composite shielding system 1000 for fusion reactor piping and control systems, according to an embodiment of the present invention.

[0041] The integrated composite shielding system 1000 for fusion reactor piping and control systems of this invention is an integrated selective saturation composite shielding system for fusion reactors adapted to the regional interference characteristics of fusion reactors. It adopts a graded shielding design concept, configuring different shielding structures according to the interference intensity of different areas. The integrated composite shielding system 1000 for fusion reactor piping and control systems of this invention includes a fully configured shielding unit 100 for the NBI / ECRH hall (reference). Figure 1 Simplified shielding unit for lithium-lead circuit room 200 (reference) Figure 2 ) and through-wall shielding connection assembly 300 (reference) Figure 3 ).

[0042] The NBI / ECRH main hall fully-equipped shielding unit 100, the simplified lithium-lead loop room shielding unit 200, and the through-wall shielding connection assembly 300 all have a three-layer basic shielding structure 2 surrounding the pipe 1. Pipe 1 can refer to the original pipes of the fusion equipment or the housing of the control system cabinet; for example, it can be the beam pipes and control system cabinet housing within the NBI / ECRH main hall. The cross-section of pipe 1 can be circular, rectangular, or other shapes. The three-layer basic shielding structure 2 consists of an inner high-conductivity shielding layer 201, a middle selective saturation magnetic shielding layer 202, and an outer high-conductivity shielding layer 203 from the inside out. The inner high-conductivity shielding layer 201 faces the protected equipment and is used to shield against high-frequency microwave and transient electric field interference, while also providing overall support. The middle selective saturation magnetic shielding layer 202 is the only functional layer for DC, power frequency, and pulsed magnetic shielding. The outer high-conductivity shielding layer 203 faces the host magnetic field side and is used to shield against externally incident high-frequency electromagnetic interference, while suppressing edge leakage magnetic flux of the middle selective saturation magnetic shielding layer, and also providing overall support.

[0043] The NBI / ECRH hall full-configuration shielding unit 100 also includes an additional low-activation tungsten radiation shielding layer 3 on the outer periphery of the outer high-conductivity shielding layer 203 of the three-layer basic shielding structure 2. The low-activation tungsten radiation shielding layer 3 is used to shield the hard X-ray radiation generated by NBI. The NBI / ECRH hall full-configuration shielding unit 100 has a total of four shielding layers. The NBI / ECRH hall full-configuration shielding unit 100 is suitable for beam pipes and control system cabinets in the NBI / ECRH hall.

[0044] The simplified shielding unit 200 for lithium-lead loop rooms uses only a three-layer basic shielding structure 2. That is, compared with the fully configured shielding unit 100 in the NBI / ECRH hall, the simplified shielding unit 200 for lithium-lead loop rooms eliminates the low-activation tungsten radiation shielding layer 3, and has a total of three shielding layers. The simplified shielding unit 200 for lithium-lead loop rooms is suitable for pipes and control system cabinets in lithium-lead loop rooms.

[0045] The through-wall shielding connection assembly 300 also includes a through-wall shielding sleeve 4 and a shielding gland (not shown in the figure) fitted on the outer periphery of the three-layer basic shielding structure 2. The through-wall shielding connection assembly 300 is used to achieve electromagnetic shielding continuity when pipes and cables pass through the wall.

[0046] The core working principle of the integrated composite shielding system 1000 for fusion reactor piping and control system in this embodiment of the invention is as follows: The principle of selective shielding against DC stray magnetic fields. Utilizing the "magnetic field selective response" characteristic of the intermediate selective saturation magnetic shielding layer 202, differentiated processing of magnetic fields of varying intensities is achieved: When in a strong magnetic field of at least 4T from the host, the magnetic induction intensity of the intermediate selective saturation magnetic shielding layer 202 far exceeds its saturation magnetic flux density (0.4T), the magnetic domains are fully oriented, and the permeability drops sharply to near vacuum (μ≈1.001μ0). Magnetic field lines can pass through the shielding layer without obstruction, thus not significantly disturbing the host's magnetic field; when in a stray magnetic field of 50mT or a residual pulse magnetic field of 40mT, the intermediate selective saturation magnetic shielding layer 202 is far from saturated, and its initial permeability μ i With a strength of ≥5000, magnetic field lines will preferentially close along the interior of the ferrite layer with high permeability, thus being guided away from the protected area to achieve efficient shielding.

[0047] Power frequency and pulsed magnetic field shielding principle. For a 50Hz power frequency magnetic field and a 1kHz~10kHz pulsed magnetic field generated by NBI, when the intermediate selective saturated magnetic shielding layer 202 is in a weak field region (i.e., the amplitude of the interference field itself is much lower than the saturation magnetic flux density of the intermediate selective saturated magnetic shielding layer 202), the intermediate selective saturated magnetic shielding layer 202 is still in an unsaturated high permeability state, and shielding is achieved through the magnetic shunt effect.

[0048] Broadband electromagnetic interference and transient pulse shielding principle. Full-band electromagnetic shielding is achieved using an inner high-conductivity shielding layer 201 and an outer high-conductivity shielding layer 203. The shielding mechanisms differ significantly across frequency bands: High-frequency electromagnetic interference (30MHz~1GHz): The high conductivity of the inner and outer high-conductivity shielding layers 201 and 203 generates a strong impedance mismatch, resulting in a shielding effectiveness ≥80dB in this band, far exceeding the 40dB / 30dB requirement specified in fusion reactor electromagnetic compatibility technology. Millimeter-wave microwaves (1GHz~170GHz): The impedance mismatch effect of the inner and outer high-conductivity shielding layers 201 and 203 reflects most of the incident microwave energy, while the remaining trace energy is absorbed by the intermediate selective saturation magnetic shielding layer 202 through hysteresis loss and dielectric loss. Transient electromagnetic pulse (10ns~1μs): The high conductivity of the inner high conductivity shielding layer 201 and the outer high conductivity shielding layer 203 can quickly discharge transient charges. At the same time, the Faraday cage effect formed by the double-layer structure (i.e. the inner high conductivity shielding layer 201 and the outer high conductivity shielding layer 203) can attenuate the electric field pulse by more than 60dB, effectively protecting the internal electronic equipment from breakdown.

[0049] The principle of hard X-ray radiation shielding. The low-activated tungsten radiation shielding layer 3 uses tungsten with extremely high atomic number (Z=74) and density (19.3 g / cm³), exhibiting strong attenuation capabilities for hard X-rays ranging from 10 to 100 keV. A 1.5 mm thick low-activated tungsten foil attenuates ≥99% of 100 keV X-rays, and the half-life of tungsten activation products is much shorter than that of lead activation products, meeting the low-activation requirements of fusion reactors. The low-activated tungsten radiation shielding layer 3 protects precision instruments and cables adjacent to the beam pipe, preventing the generation of secondary electrons and scattered radiation around the beam pipe.

[0050] Compared with the prior art, the integrated composite shielding system 1000 for fusion reactor piping and control system of the present invention has the following significant advantages: I. This invention resolves the fundamental contradiction between "shielding stray fields and not disturbing the main field" from a physical perspective: It pioneers the selective saturation magnetic shielding principle, utilizing the differentiated magnetic properties of the intermediate selective saturation magnetic shielding layer 202 under different magnetic field intensities—deeply saturated in a 4T strong field with incremental permeability approaching vacuum, and unsaturated in a 50mT weak field with permeability reaching thousands—achieving an adaptive function that avoids disturbing the main magnetic field in strong field regions and efficiently shields stray magnetic fields in weak field regions. COMSOL multiphysics simulation results show that under a 4T background magnetic field, the local magnetic field distortion ΔB / B introduced by the shielding structure of this invention is ≤0.005%, fully meeting the ITER requirement of ≤0.01% tolerance; while the distortion introduced by a silicon steel shielding layer of the same size exceeds 1.2%, far exceeding the standard. In a weak field region without strong field bias, the shielding effectiveness against a 50mT stray magnetic field is ≥23dB, reducing the MHD voltage drop by more than 90%.

[0051] II. Fully Meets the Requirements for All Operating Conditions and Regional Interference of Fusion Reactors: It is currently the only shielding solution that simultaneously meets the electromagnetic compatibility technical requirements of fusion reactors, the GB / T 17626.8 national standard, and the regional interference characteristics of fusion reactor sites, without requiring additional independent power frequency magnetic field shielding devices. It effectively shields against 50mT DC stray magnetic fields, 50Hz power frequency magnetic fields, NBI transient electromagnetic pulses, 1GHz~170GHz high-frequency microwaves, and hard X-rays.

[0052] III. Graded shielding design with excellent economic efficiency: Differentiated shielding configurations are adopted according to the actual interference intensity of different areas. The lithium-lead circuit room adopts a simplified three-layer basic shielding structure2, eliminating the low-activation tungsten radiation shielding layer3. The intermediate selective saturated magnetic shielding layer 202 can be optimized to about 5mm, reducing costs and weight, and achieving the best cost performance while ensuring safety.

[0053] Fourth, it achieves full-link system-level electromagnetic protection: For the first time, the shielding of liquid metal loop pipeline, NBI beam pipeline, control system cabinet, and through-wall connection shielding are unified into the same technical architecture, which completely eliminates the hidden danger of electromagnetic interference coupling into the control system through through-wall holes, cable trenches, etc., and greatly improves the overall reliability of the system.

[0054] V. Excellent Low Activation and High Temperature Resistance: The shielding structure of this invention exhibits a short half-life of the main activation products generated under fusion neutron irradiation, with no... 60 Co-type long-half-life, high-activity nuclides exist, with only trace amounts of long-half-life, low-activity nuclides present, which meets the requirements for low-activation waste management in fusion reactors and is beneficial for radioactive waste management during reactor decommissioning; with a reliable anti-oxidation coating, it can withstand a high-temperature environment of 600°C for a long time, meeting the operating temperature requirements of lithium-lead loops and NBI systems.

[0055] VI. The structure is reliable and the installation and maintenance are convenient.

[0056] In summary, the integrated composite shielding system 1000 for fusion reactor piping and control systems of this invention solves the fundamental contradiction between "shielding stray fields and not disturbing the main field" from a physical perspective. It adopts a graded shielding design concept, employing differentiated configurations for varying residual interference intensities at locations where piping and cables pass through the NBI / ECRH lobby, lithium-lead loop rooms, and walls. This comprehensively meets the electromagnetic compatibility requirements of the fusion reactor, the GB / T 17626.8 national standard, and on-site operating conditions, and is suitable for the special operating conditions of fusion reactors, such as low activation and high temperature resistance. The integrated composite shielding system 1000 for fusion reactor piping and control systems of this invention is particularly suitable for electromagnetic protection of liquid metal cladding loops and auxiliary heating systems.

[0057] In some embodiments, both the inner high-conductivity shielding layer 201 and the outer high-conductivity shielding layer 203 are integral continuous cylindrical structures made of pure molybdenum foil, with a thickness of 0.4~0.6mm.

[0058] The inner high-conductivity shielding layer 201 is made of continuous cylindrical pure molybdenum foil, which is mainly used to shield high-frequency microwaves and transient electric field interference, while providing overall structural support; the outer high-conductivity shielding layer 203 is made of continuous cylindrical pure molybdenum foil, which is used to shield externally incident high-frequency electromagnetic interference, while suppressing edge leakage magnetic field of the middle ferrite layer, and providing overall structural support.

[0059] The inner high-conductivity shielding layer 201 and the outer high-conductivity layer operate on the principle of broadband electromagnetic interference and transient pulse shielding. Full-band electromagnetic shielding is achieved using double-layered continuous cylindrical pure molybdenum foil. The shielding mechanisms differ significantly across frequency bands: High-frequency electromagnetic interference (30MHz~1GHz): The high conductivity of molybdenum generates strong impedance mismatch; the shielding effectiveness of 0.5mm thick pure molybdenum foil in this band is ≥80dB, far exceeding the 40dB / 30dB requirement specified in fusion reactor electromagnetic compatibility technology. Millimeter-wave microwaves (1GHz~170GHz): The impedance mismatch effect of molybdenum reflects most of the incident microwave energy; the remaining trace energy is absorbed by the intermediate ferrite layer through hysteresis and dielectric losses. Transient electromagnetic pulses (10ns~1μs): The high conductivity of the continuous molybdenum foil rapidly discharges transient charges, while the Faraday cage effect formed by the double-layered continuous cylindrical pure molybdenum foil attenuates the electric field pulse by more than 60dB, effectively protecting internal electronic equipment from breakdown.

[0060] In some embodiments, the intermediate selective saturation magnetic shielding layer 202 is spliced ​​from low-activation manganese-zinc ferrite tiles 2021; the thickness of the intermediate selective saturation magnetic shielding layer 202 in the fully configured shielding unit of the NBI / ECRH hall (i.e., the thickness of the low-activation manganese-zinc ferrite tiles 2021) is 5~6mm, and the thickness of the intermediate selective saturation magnetic shielding layer 202 in the simplified shielding unit 200 of the lithium-lead circuit room (i.e., the thickness of the low-activation manganese-zinc ferrite tiles 2021) is 5~5.5mm.

[0061] The intermediate selective saturation magnetic shielding layer 202 is the only functional layer for DC, power frequency, and pulse magnetic shielding. Its working principle is as follows: The principle of selective shielding against DC stray magnetic fields. Utilizing the "magnetic field selective response" characteristic of low-activation manganese-zinc ferrite, differentiated processing of magnetic fields of varying intensities is achieved: When placed in a strong magnetic field of at least 4T in the host, the magnetic induction intensity of the low-activation manganese-zinc ferrite far exceeds its saturation magnetic flux density (0.4T), the magnetic domains are fully oriented, and the permeability drops sharply to near vacuum (μ≈1.001μ0). Magnetic field lines can pass through the shielding layer without obstruction, thus not significantly disturbing the host's magnetic field; when placed in a stray magnetic field of 50mT or a residual pulse magnetic field of 40mT, the low-activation manganese-zinc ferrite is far from saturated, and its initial permeability μ i With a strength of ≥5000, magnetic field lines will preferentially close along the interior of low-activation manganese-zinc ferrite with high magnetic permeability, thereby being guided away from the protected area and achieving efficient shielding.

[0062] Shielding Principles for Power Frequency and Pulsed Magnetic Fields. For a 50Hz power frequency magnetic field and a 1kHz~10kHz pulsed magnetic field generated by NBI, when the shielding layer is in a weak field region (i.e., the amplitude of the interference field itself is much lower than the saturation magnetic flux density of the low-activated manganese zinc ferrite), the low-activated manganese zinc ferrite remains in an unsaturated high-permeability state, achieving shielding through the magnetic shunt effect. Experimental verification shows that a 5mm thick low-activated manganese zinc ferrite layer has a shielding effectiveness ≥55dB against a 50Hz power frequency magnetic field and ≥22dB against a 10kHz pulsed magnetic field. It can fully withstand the 200A / m short-term power frequency magnetic field impact specified in GB / T 17626.8 and the 40mT residual pulsed magnetic field in a lithium-lead circuit room.

[0063] It should be noted that the shielding structure of this invention exhibits excellent low activation and high temperature resistance: it is made entirely of low-activation materials (molybdenum, low-activation ferrite, alumina, and low-activation tungsten), and the main activation products generated under fusion neutron irradiation have short half-lives and no... 60 Co-type long-half-life, high-activity nuclides exist, with only trace amounts of long-half-life, low-activity nuclides present, which meets the requirements for low-activation waste management in fusion reactors and is beneficial for radioactive waste management during reactor decommissioning; with a reliable anti-oxidation coating, it can withstand a high-temperature environment of 600°C for a long time, meeting the operating temperature requirements of lithium-lead loops and NBI systems.

[0064] In some embodiments, the intermediate selective saturation magnetic shielding layer 202 is provided with axially uniformly distributed narrow slots, for example, one narrow slot is provided every 10°, for a total of 36 narrow slots. The narrow slots are the joints between circumferentially adjacent low-activation manganese zinc ferrite tiles 2021, and the width of the narrow slots is 0.1~0.2mm.

[0065] The narrow slit only penetrates the intermediate selective saturation magnetic shielding layer 202, while the inner high conductivity shielding layer 201 and the outer high conductivity shielding layer 203 remain as a whole. This not only cuts off the circumferential eddy current loop of the intermediate selective saturation magnetic shielding layer 202, avoiding the generation of large induced currents that disturb the host magnetic field when the host magnetic field changes rapidly, but also provides reliable overall structural support through the inner high conductivity shielding layer 201 and the outer high conductivity shielding layer 203.

[0066] In some embodiments, the low-activation manganese zinc ferrite tile 2021 is bonded to the inner high-conductivity shielding layer 201 by a high-temperature resistant inorganic adhesive, thereby achieving reliable fixation of the low-activation manganese zinc ferrite tile 2021.

[0067] In some embodiments, the low-activation tungsten radiation shielding layer 3 is made of 1-2 mm thick low-activation tungsten foil, used to shield the 10-100 keV hard X-ray radiation generated by NBI.

[0068] In some embodiments, such as Figure 4As shown, the integrated composite shielding system 1000 for the fusion reactor piping and control system adopts a segmented design along the axial direction, forming several shielding sections with a length of 0.8~1.2m. The inner highly conductive shielding layers 201 of adjacent shielding sections are insulated and overlapped with each other, and the outer highly conductive shielding layers 203 of adjacent shielding sections are insulated and overlapped with each other. This ensures the continuity of 170GHz microwave and electromagnetic pulse shielding, while blocking the direct current path through the insulated overlap.

[0069] In some embodiments, such as Figure 4 As shown, the overlapping areas of the inner high-conductivity shielding layers 201 of adjacent shielding sections and the overlapping areas of the outer high-conductivity shielding layers 203 of adjacent shielding sections are respectively insulated with alumina ceramic gaskets 204, with an insulation resistance ≥10 Ω·cm. 12 Ω. This ensures the continuity of 170GHz microwave and electromagnetic pulse shielding, while blocking the direct current path through the insulating overlap.

[0070] In some embodiments, the overlap area of ​​the inner highly conductive shielding layer 201 of adjacent shielding sections is 9-11 mm wide, and the overlap area of ​​the outer highly conductive shielding layer 203 of adjacent shielding sections is 14-16 mm wide. This ensures a reliable connection between adjacent shielding sections.

[0071] In some embodiments, the joints between the shielding sections of the control system cabinets in the NBI / ECRH lobby and the control system cabinets in the lithium-lead circuit room, and the adjacent shielding sections installed between pipelines, are bent and overlapped, with an overlap area width ≥ 20 mm. Specifically, the inner highly conductive shielding layers 201 of adjacent shielding sections are bent and overlapped while remaining insulated from each other, and the outer highly conductive shielding layers 203 of adjacent shielding sections are bent and overlapped while remaining insulated from each other. This ensures the continuity of 170 GHz microwave and electromagnetic pulse shielding, while simultaneously blocking the direct current path through the insulating overlap.

[0072] In some embodiments, the observation window on the shielding section of the control system cabinet installed in the NBI / ECRH lobby is made of molybdenum-plated lead glass; the observation window on the shielding section of the control system cabinet installed in the aluminum-lead circuit room is made of molybdenum-plated glass; the ventilation openings of the shielding sections of the control system cabinets installed in the NBI / ECRH lobby and the control system cabinets installed in the lithium-lead circuit room are made of honeycomb molybdenum plates with a honeycomb aperture of 2mm, a depth of 20mm, and a shielding effectiveness of ≥35dB; the cabinet inlet of the shielding section of the control system cabinets installed in the NBI / ECRH lobby and the control system cabinets installed in the lithium-lead circuit room is made of molybdenum-plated shielded glands.

[0073] In some embodiments, the molybdenum shielded gland has multiple layers of beryllium copper spring fingers inside, which make 360° low-impedance contact with the cable shielding layer; for magnetically sensitive cables, an annular low-activation manganese-zinc ferrite magnetic ring 8 is added inside the molybdenum shielded gland to achieve magnetic shielding continuity.

[0074] In some embodiments, such as Figure 3 As shown, the structure of the through-wall shielding sleeve 4 is the same as that of the three-layer basic shielding structure 2. Specifically, the through-wall shielding sleeve 4 consists of an inner high-conductivity shielding layer 201, a middle selective saturation magnetic shielding layer 202, and an outer high-conductivity shielding layer 203, from the inside out. Both the inner and outer high-conductivity shielding layers 201 and 203 are integral continuous cylindrical structures made of pure molybdenum foil. The middle selective saturation magnetic shielding layer 202 is constructed by splicing together low-activation manganese-zinc ferrite tiles 2021. The through-wall shielding sleeve 4 passes through the wall and extends 90-100mm beyond the wall at both ends. Both ends of the through-wall shielding sleeve are evenly overlapped with the wall's reinforcing mesh and the three-layer basic shielding structure 2 located within the through-wall shielding sleeve 4 via molybdenum foil at a 360° overlap width of ≥50mm. This achieves electromagnetic shielding continuity.

[0075] In some embodiments, a 12-18mm annular gap is reserved between the three-layer basic shielding structure 2 and the pipe 1. The annular gap is filled with alumina fiber thermal insulation material 5, which not only serves as thermal insulation (able to withstand the radiant heat of the pipe 1 at 600℃), but also compensates for the thermal expansion differences between different materials.

[0076] In some embodiments, the three-layer basic shielding structure 2 is supported by alumina ceramic support blocks 6 evenly distributed circumferentially, for example, by three alumina ceramic support blocks 6 evenly distributed circumferentially, to ensure that each shielding section is coaxial with the pipe 1.

[0077] In some embodiments, each shielding section is connected to the common grounding reference plane of the hall at multiple points through multiple grounding electrodes 7, with a grounding resistance ≤0.5Ω; two low-activation manganese-zinc ferrite magnetic rings 8 are connected in series near each grounding electrode 7. Specifically, the grounding electrode 7 is a molybdenum strip, and each shielding layer is connected to the common grounding reference plane of the hall at multiple points through three molybdenum strips, each 20mm wide and 0.5mm thick, with a grounding resistance ≤0.5Ω; two low-activation manganese-zinc ferrite magnetic rings 8 are connected in series near each grounding molybdenum strip, achieving high impedance selective grounding for high-frequency transient currents above 1kHz and low impedance selective grounding for DC / power frequency currents, effectively dissipating electrostatic charges while avoiding ground loop interference and ground potential backflash.

[0078] The present invention will now be described in detail with reference to specific embodiments, experimental data, and multiphysics simulation results.

[0079] Example 1 is a full-configured shielding unit 100 for NBI / ECRH hall matching the DN50 auxiliary pipeline in the fusion reactor NBI hall. It is suitable for beam pipelines and control system cabinets in the NBI / ECRH hall, and needs to cope with the complex interference environment of 50mT class DC stray magnetic field, NBI transient electromagnetic pulse, 170GHz microwave and hard X-ray radiation at the same time.

[0080] Structural parameters of the full-configured shielding unit 100 for NBI / ECRH hall: Overall outer diameter: 88mm, overall inner diameter: 56mm, overall length: 1000mm; Inner high-conductivity shielding layer 201: pure molybdenum foil, 0.5mm in thickness, overall continuous cylindrical shape; intermediate selective saturated magnetic shielding layer 202: low-activation manganese-zinc ferrite tiles 2021, 6mm in thickness, spliced by 36 tiles, with 36 axial narrow slits, 0.15mm in width; outer high-conductivity shielding layer 203: pure molybdenum foil, 0.5mm in thickness, overall continuous cylindrical shape; low-activation tungsten radiation shielding layer 3: low-activation tungsten foil, 1.5mm in thickness; annular gap: 15mm, filled with aluminum oxide fiber thermal insulation material 5; ceramic support blocks: 3 pieces, made of aluminum oxide, 15mm in height, uniformly distributed in the circumferential direction; the low-activation manganese-zinc ferrite tiles 2021 are fixed: pasted on the inner wall of the inner high-conductivity shielding layer 201 through high-temperature resistant inorganic adhesive.

[0081] Performance test requirements (tested under weak field conditions, interference field amplitude 50mT / 40mT): DC stray magnetic field shielding effectiveness is not less than 24dB (incident 50mT → outgoing 2.0mT); 10kHz pulse magnetic field shielding effectiveness is not less than 25dB (can withstand 120mT peak pulse magnetic field); 170GHz microwave shielding effectiveness is not less than 45dB; NBI transient electromagnetic pulse shielding effectiveness is not less than 60dB; 100keV hard X-ray attenuation rate is not less than 99%.

[0082] 4T magnetic field disturbance simulation (COMSOL simulation): the relative distortion of the local magnetic field introduced by the full-configured shielding unit 100 for NBI / ECRH hall of the present invention meets the tolerance requirement of ≤ 0.01%; the distortion introduced by a silicon steel shielding layer of the same size far exceeds the standard, and it does not have broadband microwave shielding capability.

[0083] Example 2 is a simplified shielding unit 200 for the lead-lithium loop room matching the DN50 main pipeline in the fusion reactor lead-lithium loop room, which is designed for residual interference after attenuation by 10-meter spacing and 1-meter concrete wall. The wall has effectively attenuated hard X-rays (attenuation rate ≥ 99.999%) and high-frequency microwaves (attenuation rate ≥ 60dB), and the main residual threats are 40mT class pulsed magnetic field and 1kV / m class transient electric field.

[0084] Structural parameters of the simplified shielding unit 200 for lithium-lead circuit rooms: Overall outer diameter: 86mm, overall inner diameter: 56mm, overall length: 1000mm; Inner high-conductivity shielding layer 201: pure molybdenum foil, 0.5mm thick, continuous cylindrical shape; Middle selective saturation magnetic shielding layer 202: low-activation manganese-zinc ferrite tile 2021, 5mm thick, composed of 36 tiles spliced ​​together, with 36 axial narrow slits, 0.15mm wide; Outer high-conductivity shielding layer 203: pure molybdenum foil, 0.5mm thick, continuous cylindrical shape; Low-activation tungsten radiation shielding layer 3 is omitted; The remaining structure is the same as in Example 1.

[0085] Performance test results requirements: DC stray magnetic field shielding effectiveness not less than 22.5dB (incident 40mT → outgoing 2.4mT); 10kHz pulse magnetic field shielding effectiveness not less than 22dB (can withstand 40mT residual pulse magnetic field); 170GHz microwave shielding effectiveness not less than 43dB; transient electromagnetic pulse shielding effectiveness not less than 58dB (1kV / m incident pulse).

[0086] Simulation results of 4T magnetic field disturbance (COMSOL simulation): The local magnetic field relative distortion introduced by the simplified shielding unit 200 of the lithium-lead loop room of this invention meets the tolerance requirement of ≤0.01%; the distortion introduced by the silicon steel shielding layer of the same size far exceeds the standard.

[0087] Example 3 is a standard 19-inch control system shielded cabinet in the lithium-lead loop room of a fusion reactor. It is a form of a simplified shielding unit 200 for the lithium-lead loop room and is suitable for overall shielding protection of control equipment such as PLCs and data acquisition cards in the lithium-lead loop room.

[0088] Structural parameters of the shielded cabinet: Cabinet dimensions: 600mm (width) × 800mm (depth) × 2000mm (height); Shell structure: Inner high-conductivity shielding layer 201 is a 0.5mm thick continuous molybdenum foil; Middle selective saturation magnetic shielding layer 202 is a 5mm thick low-activation manganese-zinc ferrite tile 2021; Outer high-conductivity shielding layer 203 is a 0.5mm thick continuous molybdenum foil; The middle selective saturation magnetic shielding layer 202 has vertical narrow slits, one every 10°, for a total of 36 slits, penetrating only the ferrite. Layers; Joint treatment: All joints are made of molybdenum foil with folded overlap, with an overlap width of 20mm; Observation window: 400mm×300mm molybdenum-plated glass, with an optical transmittance of ≥85%, while ensuring the continuity of electric field / microwave shielding; Ventilation openings: 6 honeycomb molybdenum plate ventilation openings, with a honeycomb aperture of 2mm and a depth of 20mm; Cable inlet: 8 molybdenum shielded glands, with beryllium copper spring fingers and annular ferrite magnetic rings inside; Grounding: 6 points connected to the public grounding reference plane in the lobby, with 2 ferrite magnetic rings connected in series at each point.

[0089] Performance test results requirements: Shielding effectiveness of 30MHz~230MHz not less than 40dB; shielding effectiveness of 30MHz~1000MHz not less than 30dB; 50Hz power frequency magnetic field immunity: passing a 200A / m short-time magnetic field test, with PLC, data acquisition cards, and other equipment inside the cabinet operating normally; DC stray magnetic field shielding effectiveness not less than 22dB; insulation performance: insulation resistance between the cabinet and ground ≥10Ω. 12 Ω.

[0090] Example 4 is a DN50 main pipeline wall-penetrating shielding sleeve 4, used to ensure electromagnetic shielding continuity when the pipeline passes through a 1-meter-thick reinforced concrete wall.

[0091] Structural parameters of the through-wall shielding sleeve 4: The sleeve length is based on the wall thickness, extending 100mm from each end of the wall; Structure: The inner high-conductivity shielding layer 201 is a 90mm diameter molybdenum tube, the middle selective saturation magnetic shielding layer 202 is a 5mm thick low-activation manganese-zinc ferrite tile 2021, and the outer high-conductivity shielding layer 203 is a 100mm diameter molybdenum tube; Overlap at both ends: It overlaps with the wall reinforcement mesh and pipe shielding layer 360° with molybdenum foil, with an overlap width of 50mm; Gap filling: Expansion cement is filled between the sleeve and the wall to ensure reliable fixation. The annular gap between the inside of the through-wall shielding sleeve 4 and the pipe 1 is filled with alumina fiber as a compressible heat insulation layer to adapt to the differential thermal expansion of the wall and pipe under high temperature and irradiation.

[0092] Performance expectations: shielding effectiveness at wall penetrations <2dB; DC magnetic field shielding continuity ≥20dB; 170GHz microwave shielding continuity ≥40dB.

[0093] Compared to traditional silicon steel shielding using 1mm thick non-oriented silicon steel sheets to make a shielding cylinder for the same size pipe, the calculation results are as follows: local disturbance to the host magnetic field under a 4T magnetic field: 1.5; shielding effectiveness of 30MHz~230MHz is less than 40dB; long half-life is produced after neutron irradiation. 60 Co is not advisable.

[0094] Comparing the shielded cabinet of the same size made from 1.5mm thick cold-rolled steel plate, the calculation results are as follows: DC stray magnetic field shielding effectiveness: completely unshielded; power frequency magnetic field shielding effectiveness does not meet the requirements of GB / T 17626.8; long half-life after neutron irradiation. 60 Co is not advisable.

[0095] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An integrated composite shielding system for fusion reactor piping and control systems, characterized in that, The system includes a fully configured shielding unit for the NBI / ECRH lobby, a simplified shielding unit for the lithium-lead circuit room, and a through-wall shielding connection assembly. Each of these components has a three-layer basic shielding structure fitted over the pipe. From the inside out, the three layers consist of an inner high-conductivity shielding layer, a middle selective saturation magnetic shielding layer, and an outer high-conductivity shielding layer. The inner high-conductivity shielding layer faces the protected equipment and shields against high-frequency microwaves and transient electric field interference. The middle selective saturation magnetic shielding layer is the only functional layer for DC, power frequency, and pulse magnetic shielding. The outer high-conductivity shielding layer faces the host magnetic field and shields against externally incident high-frequency electromagnetic interference while suppressing edge leakage magnetic flux from the middle selective saturation magnetic shielding layer. The NBI / ECRH hall full-configuration shielding unit also includes a low-activation tungsten radiation shielding layer added to the outer periphery of the outer high-conductivity shielding layer of the three-layer basic shielding structure. The low-activation tungsten radiation shielding layer is used to shield the hard X-ray radiation generated by NBI. The NBI / ECRH hall full-configuration shielding unit is suitable for beam pipes and control system cabinets in the NBI / ECRH hall. The simplified shielding unit for lithium-lead circuit rooms uses only the three-layer basic shielding structure and is suitable for pipes and control system cabinets in lithium-lead circuit rooms. The through-wall shielding connection assembly also includes a through-wall shielding sleeve and a shielding gland fitted on the outer periphery of the three-layer basic shielding structure. The through-wall shielding connection assembly is used to achieve electromagnetic shielding continuity when pipes and cables pass through walls.

2. The integrated composite shielding system for fusion reactor piping and control system according to claim 1, characterized in that, Both the inner and outer highly conductive shielding layers are integral continuous cylindrical structures made of pure molybdenum foil, with a thickness of 0.4~0.6mm.

3. The integrated composite shielding system for fusion reactor piping and control system according to claim 1, characterized in that, The intermediate selective saturated magnetic shielding layer is made of low-activation manganese-zinc ferrite tiles; the thickness of the intermediate selective saturated magnetic shielding layer in the fully configured shielding unit of the NBI / ECRH hall is 5~6mm, and the thickness of the intermediate selective saturated magnetic shielding layer in the simplified shielding unit of the lithium-lead circuit room is 5~5.5mm.

4. The integrated composite shielding system for fusion reactor piping and control system according to claim 1, characterized in that, The intermediate selective saturation magnetic shielding layer has axially uniformly distributed narrow slits, the width of which is 0.1~0.2mm.

5. The integrated composite shielding system for fusion reactor piping and control system according to claim 3, characterized in that, The low-activation manganese-zinc ferrite tiles are bonded to the inner high-conductivity shielding layer using a high-temperature resistant inorganic adhesive.

6. The integrated composite shielding system for fusion reactor piping and control system according to claim 1, characterized in that, The low-activation tungsten radiation shielding layer uses 1-2 mm thick low-activation tungsten foil to shield against 10-100 keV hard X-ray radiation generated by NBI.

7. The integrated composite shielding system for fusion reactor piping and control system according to claim 1, characterized in that, The integrated composite shielding system for the fusion reactor pipeline and control system adopts a segmented design along the axial direction to form several shielding sections. The inner highly conductive shielding layers of adjacent shielding sections are insulated from each other and overlapped. The outer highly conductive shielding layers of adjacent shielding sections are insulated from each other and overlapped.

8. The integrated composite shielding system for fusion reactor piping and control system according to claim 7, characterized in that, Alumina ceramic gaskets are used to insulate the overlapping areas of the inner highly conductive shielding layers of adjacent shielding sections and the overlapping areas of the outer highly conductive shielding layers of adjacent shielding sections, with an insulation resistance ≥10 Ω·cm. 12 Ω.

9. The integrated composite shielding system for fusion reactor piping and control system according to claim 7, characterized in that, The width of the overlap area of ​​the inner high-conductivity shielding layer of the adjacent shielding sections is 9~11mm, and the width of the overlap area of ​​the outer high-conductivity shielding layer of the adjacent shielding sections is 14~16mm.

10. The integrated composite shielding system for fusion reactor piping and control system according to claim 7, characterized in that, The joint between the shielding section of the control system cabinet installed in the NBI / ECRH lobby and the shielding section of the lithium-lead circuit room and the adjacent shielding section installed in the pipeline is bent and overlapped, with an overlap area width ≥20mm.

11. The integrated composite shielding system for fusion reactor piping and control system according to claim 10, characterized in that, The observation windows on the shielded sections of the control system cabinets housed in the NBI / ECRH lobby are made of molybdenum-plated lead glass; the observation windows on the shielded sections of the control system cabinets housed in the aluminum-lead circuit room are made of molybdenum-plated glass; the ventilation openings of the shielded sections of the control system cabinets housed in the NBI / ECRH lobby and the control system cabinets housed in the lithium-lead circuit room are made of honeycomb molybdenum plates with a shielding effectiveness ≥35dB; the cabinet inlets of the shielded sections of the control system cabinets housed in the NBI / ECRH lobby and the control system cabinets housed in the lithium-lead circuit room are made of molybdenum-plated shielded glands.

12. The integrated composite shielding system for fusion reactor piping and control system according to claim 11, characterized in that, The molybdenum shielded gland has multiple layers of beryllium copper spring fingers inside, which make 360° low-impedance contact with the cable shielding layer; for magnetically sensitive cables, an annular low-activation manganese zinc ferrite magnetic ring is added inside the molybdenum shielded gland.

13. The integrated composite shielding system for fusion reactor piping and control system according to claim 1, characterized in that, The structure of the through-wall shielding sleeve is the same as that of the three-layer foundation shielding structure. The through-wall shielding sleeve passes through the wall and extends 90-100mm from the wall at both ends. The two ends of the through-wall shielding sleeve are evenly overlapped with the wall steel mesh and the pipe shielding layer by molybdenum foil at 360°, with an overlap width of ≥50mm.

14. The integrated composite shielding system for fusion reactor piping and control system according to any one of claims 1-13, characterized in that, A 12-18mm annular gap is reserved between the three-layer basic shielding structure and the pipeline, and the annular gap is filled with alumina fiber thermal insulation material.

15. The integrated composite shielding system for fusion reactor piping and control system according to claim 14, characterized in that, The three-layer basic shielding structure is supported by alumina ceramic support blocks evenly distributed along the circumference between it and the pipeline.

16. The integrated composite shielding system for fusion reactor piping and control system according to claim 7, characterized in that, Each shielding section is connected to the public grounding reference plane of the hall through multiple grounding electrodes at multiple points, with a grounding resistance ≤0.5Ω; two low-activation manganese-zinc ferrite magnetic rings are connected in series at each grounding electrode near the shielding section.

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