Heat Shield Research Articles

Water-Borne Carbonaceous Coatings on Conducting Polymer-Modified Cotton Fabrics To Attenuate Electromagnetic Radiation

Textile-based shielding materials are gaining much importance for electromagnetic interference (EMI) shielding because of their increased flexibility compared to most existing materials. The multilayer-like architectures realized by coating textiles can be used strategically to enhance the attenuation of microwaves. Herein, we report a water-borne conductive coating capable of shielding both EM and UV radiation with good thermal stability for potential applications as smart textiles. This work tries to understand the effect of different textile pre-treatments to maximize the enhancements in properties. Cotton fabrics were initially subjected to in situ polymerization of aniline and pyrrole and subsequently coated with a carbonaceous layer containing graphene nanoplatelets and carbon nanofibers on both the sides. It was seen that both the conducting polymer layer and the carbonaceous coating work in tandem to enhance the thermal stability, UV blocking, and EMI shielding. The coated fabrics shows a shielding effectiveness of −22 dB at a thickness of 1.2 mm over a wide frequency range of 2.6–26.5 GHz, a limiting oxygen index of 26%, and remarkable UV-blocking properties with a blocking of 99.99%. Both the coating and the pre-treatment do not alter the fabric’s wettability─the surface remains hydrophilic. The coating rendered the fabric with conductivity values showing a four-order jump from the control sample. The samples show a shielding effectiveness of −22 dB, accounting for more than 99% of the incident radiation being attenuated. The attenuation happens via an absorption-dominated mechanism. The coated textile exhibits excellent heat dissipation properties, with temperatures dropping from as high as 147 to 41 °C in just 60 s.

Modified Brayton refrigeration cycles for forced-flow cooling of HTS fusion system

A thermodynamic study is performed to identify the suitable refrigeration cycles for emerging application to HTS (high-temperature superconductors) fusion system. According to the recent reports on compact and efficient fusion system, the HTS magnets are supposed to operate around at 20 K by forced-flow cooling of helium gas. In addition to the main cryogenic load for magnets, there are other cooling requirements, including the refrigeration of thermal shield and current leads. In order to compose a closed refrigeration system without liquid-nitrogen supply or any boil-off loss, modified Brayton cycles are designed to cover the cooling loads with a circulation loop of coolant for magnets, thermal shield, and current leads. Innovative design is also proposed to integrate the cooling loop with the refrigeration cycle, as helium gas is used as coolant and refrigerant. A variety of modified cycles with forced-flow cooling are optimized through iterative analysis with process simulator (Aspen HYSYS) and the real-gas properties of helium. It is verified that the integrated refrigeration cycles with cooling loop could have a great merit in thermodynamic efficiency as well as the simpler operation without any cryogenic pumping device. It is also demonstrated that a single refrigeration cycle could be designed to fully cover all the cooling requirements for HTS fusion system.

Design and mechanical properties of SiC reinforced Gd2O3/6061Al neutron shielding composites

This paper presented a new type of neutron absorption material used in the storage and transportation of spent fuel in nuclear power plants as SiC/Gd2O3/6061Al composites (SGAC). The optimal component proportion of composites was designed by neutron shielding simulation with MCNP5 software and mechanical property simulation with LAMMPS software. The influence of SiC content on the neutron shielding performance and mechanical properties of the composites was explored by numerical simulation. SGAC with different content of SiC were prepared by SPS technology. The thermal neutron shielding properties, microstructure and mechanical properties for SGAC were analyzed by neutron shielding tests, XRD, typical SEM, TEM, and tensile tests. The neutron shielding test shows that the neutron shielding performance of (0 wt%-25 wt%) SiC/5 wt% Gd2O3/6061Al SGAC with a thickness of 5 mm all reach above 99.5%. Nanometer Gd2O3 particles and micron SiC particles play intragranular and intergranular reinforcement effects on Al matrix respectively. A new phase Al4SiC4 is generated at the interface of the two phases, facilitating the connection of interfaces. (15 wt% SiC+5 wt% Gd2O3)/6061Al shows superior mechanical properties with the tensile strength of 196 MPa and the elongation of 11%.

METHODOLOGICAL AND TECHNOLOGICAL BASICS OF RESEARCH OF SOLID FUEL ROCKET ENGINES OF ATTACK MEANS

The article presents methodical and technological approaches to the study of performance and confirming the main characteristics of solid fuel rocket engines (SFRI), which are part of various means of destruction, as well as the main directions of organization and features of the relevant fire bench tests.
 SFRI is one of the most important components of modern means of destruction, which largely determine their tactical and technical characteristics and operational safety. By their technical condition, we mean a set of properties that change during operation and are characterized by the parameters (signs) defined by technical documentation.
 A structural-functional reliability scheme is developed to assess the reliability of SFRI, which allows taking into account not only the structural elements, but also phenomena that can lead to failures, including those caused by connections between elements. According to the results of bench fire tests of SFRI that are conducted taking into account the structural-functional reliability scheme, the following information is obtained: internal ballistic, mass, energy and traction characteristics; performance of structural elements and nodes; characteristics of operational reliability and control bodies. At the end of the tests, the remaining thickness of the heat shield, the integrity of the SFRI body and the condition of the exit nozzle are also evaluated. The probability of failure-free operation is used as the main indicator of reliability. As the main indicator of reliability, SFRI uses the probability of failure-free operation for a given time of its operation. The reliability indicators of individual components are determined in accordance with its structural and functional reliability scheme.
 Fire stand tests of SFRI are carried out on a special stand, which includes original technological equipment developed and manufactured at the State Enterprise “Kyiv State Design Bureau “Luch”, the main of which are: equipment for remote launch of marching and starting АЗСД 7Х2.700.017; equipment for remote measurement and registration of operating parameters АИР 7X2.700.016; slipway С–40T–1 E240.125.00.000.0 with sensors and a sensor for registering internal gas pressure.
 The implementation of the main provisions of the methodological and technological basis of SFRI research made it possible to make scientifically based decisions regarding the possibility and expediency of their further exploitation, as well as the need to introduce a number of restrictions, including decommissioning.

Design, synthesis, and characterization of Pb-free tellurite glasses for radiation shielding applications

The melt and quench technique was used to create a new TeO2–Li2O–MoO3 glass system with the objective of providing alternative and new shielding materials for radiation safety purposes. The synthesized glasses were studied by means of their physical, thermal, and radiation shielding characteristics. It was demonstrated using Raman and FTIR spectroscopy that the insertion of Li2O and MoO3 resulted in a superimposed reduction of all Te units, including TeO3+1 and TeO3 with non-bridging oxygen, via the formation of Te(short)-O-Mo and a coordination change from MoO4 to MoO6. The densities of the prepared glasses were relatively high, having values between 4.48 and 5.11 g/cm3. Compared with TeO2-pure glass, the values for Tg and Tx substantially decrease with Li2O and MoO3 insertion. However, among prepared samples, there is only a small fluctuation in both characteristic temperatures, suggesting high thermal/composition stability. FLUKA simulations were used to estimate the photon, proton, electron, α-particle, and carbon ion shielding parameters for beam energies ranging from 15 to 15,000 keV. With changes in the chemical designation of the synthesized glasses, the mass attenuation coefficient of photons and stopping powers of charged radiation changed, gradually increasing with glass density and decreasing with Li2O and MoO3 insertion. In addition, the ability of the glasses to moderate fast neutrons declined with increases in the MoO3 and Li2O weight contents. On the contrary, the total cross section of thermal neutrons improved as glass density decreased and Li2O and MoO3 content increased. The synthesized glasses, through the evaluated parameters, showed better radiation shielding capacity compared to existing shields such as concrete and commercial RS-series glass shields.

Experimental investigations on fuel spatial distribution characteristics of aeroengine afterburner with all typical components

The fuel space distribution is a key factor in the combustion performance of afterburner. We have investigated the fuel space distribution and flow field in afterburner with all typical components. In this study, the complete afterburner test section of the afterburner is composed of a typical mixing diffuser, fuel supply system, flame stabilizer and heat shield. At the same time, we built an experimental system that enables a wide operating range of the afterburner. A temperature measuring rake, a pressure measuring rake, a Particle Image Velocimetry (PIV) system and a laser particle sizer were used to measure the flow field and fuel distribution in the combustor. It was found that the fuel particle size in the combustor space along the flow direction decreases, then increases and then gradually decreases. This is because the fuel particle size is smallest at the vortex nucleus in the recirculation zone after the stabilizer. The increase of the incoming Mach number will lead to an increase in the range of the recirculation zone behind the stabilizer, thus making the fuel distribution in the entire combustor more uniform. When the diffusion ratio is increased from 1.0 to 1.4, a significant asymmetric counter-rotating vortex pair can be formed after the stabilizer. Compared with the blockage ratio of 0.2 and 0.4, when the blockage ratio is 0.3, the fuel particle size will be reduced by 24%–32%. The spatial distribution of the fuel is not sensitive to pressure changes, and under the experimental conditions, the fuel particle size will increase by 9–25 µm with the decrease of pressure. In summary, when the diffusion ratio is 1.4 and the blockage ratio is 0.3, the afterburner has the most reasonable fuel distribution and flow field, which is conducive to the stable and efficient operation of the afterburner..

Heterogeneous stacking strategy towards carbon aerogel for thermal management and electromagnetic interference shielding

Faced with the increasing heat dissipation and electromagnetic interference (EMI) shielding problems in electronics, carbon modified polymer-based composites with significant EMI shielding and thermal management performance are of particular interest. Herein, we proposed a carbon heterogeneous stacking strategy to construct the all carbon aerogels for the modification of epoxy resin. A hybrid 3D structure of reduced graphene oxide–carbon nanotube-vertical edge-rich graphene (rGO-CNT-VG) with covalent bonding are achieved all by chemical vapor deposition, in which the pore space of skeleton is creatively modified. Due to the elaborate design and control of microstructures, the obtained hierarchical 3D rGO-CNT-VG skeleton have plenty of seamlessly bonded heterogeneous interfaces between different components, which can create additional charge polarization, interfacial polarization and dielectric relaxation to promote significantly electromagnetic microwave attenuation and conversion and achieve ideal EMI shielding performance. Impressively, the rGO-CNT-VG/epoxy composites possess excellent thermal conductivity of 2.46 W m−1 K−1 and EMI shielding effectiveness of 56.65 dB, which are 5.1 times and 1.9 times higher than those of the rGO/epoxy composites, respectively. More importantly, the strategy of designing all carbon heterogeneous stacking skeleton in this study provides a guidance for synergistic controlling of multifunctional performance of composites.

Preliminary development of emissivity measurement system at low temperature based on radiometric method

Thermal radiation is a major part of heat transfer in cryogenic systems, especially in vacuum environment. The emissivity of materials is an essential factor of thermal radiation, which is difficult to be precisely predicted by theoretical calculation. Thus, the direct experimental measurement becomes an inevitable, reliable method. In this paper, a preliminary emissivity measurement system using the direct radiometric method was designed and built with a G-M (Gifford-McMahon) cryocooler as the cold source. The sample plate in the apparatus can be cooled to 9.2 K, while the sample thermal radiation shield and the optical path cover can respectively reach 46.7 K and 46.9 K. At present stage, MCT (HgCdTe) detector with an effective bandwidth 2–12 μm was used in this system, which achieved the measurements of emissivities of coating Nextel 811–21, 304 stainless steel and G10 composite from 240 K to 300 K. The reliability of the system was verified by comparing the measurement results with the data already published, and the dependence of the emissivities of these materials on temperature are analyzed.

Characterization and sustained release study of starch-based films loaded with carvacrol: A promising UV-shielding and bioactive nanocomposite film

Present study was aimed to develop sustainable active films with starch/carvacrol for potential food packaging. The physicochemical, antioxidant, antibacterial and release kinetics were analyzed. The results demonstrated that carvacrol nanoemulsion (CNE) was uniformly dispersed in the film matrix and interacted with hydrogen bonds. The addition of carvacrol improved the thermal stability, UV shielding, water solubility and water vapor permeability of the films, but reduced their mechanical properties. Films prepared with CNE (≥10%) exhibited high antioxidant activity (>60%), and inhibition zones of the best antimicrobial activities achieved 28.6 ± 1.4 and 57.2 ± 3.7 (mm) against E. coli and S. aureus. The release kinetics of carvacrol from the nanocomposite films exhibited a higher carvacrol release in the acidic simulant than in the aqueous simulant at equilibrium. The dominant mechanism of carvacrol release was Fickian diffusion and showed minimal erosion. Overall, the sustainable composite films exhibited desirable physical properties and bioactivity, and could be used as edible materials for food preservation, especially for extending the shelf life of acidic foods.

Experimental study on affordable thermal insulation of exhaust manifolds using modified sheep wool waste

Internal Combustion (I.C.) engines generate lot of heat during high-speed operations. In order to prevent this heat loss, thermal insulation is mandatory to prevent heat transfer from the exhaust to the adjacent parts. The main aim of this work is to develop a thermally insulating material placed inside the catalytic converter to block the withdrawal of heat from the converter. This insulating material is usually placed between the heat shields for better heat dissipation. Comparison studies is executed between two different types of insulation material such as conventional Z-mat and super wool at various temperatures ranging from 200 °C to 800 °C for a period of 60 min and distortion results are noted at each temperature. Muffler furnace is used for the heat treatment analysis of the fabricated super wool. The composition of the novel fabricated super wool material can withstand all temperature levels between 200 °C and 800 °C, but the conventional Z-mat is suitable only up to 600 °C, where the Z-mat structure lost its capacity of insulation. Hence, the fabricated super wool material is more suitable for insulating catalytic converters and thereby it enhances the performance of engine with longer durability. In addition, hot vibration test is conducted for a duration of 50 h to check the thermal resistance capability of the super wool material. It is found that the thermal insulation is intact in position with absence of cracks or failures, inlet face erosion and retention losses. The fabricated thermal insulation mats from sheep wool waste also passed thermal shock test performed for 1500 thermal cycles. Thereby, this sort of sheep wool based affordable thermal insulation can be used for applications associated with larger thermal gradients to control the thermal-related errors such as shrinkage, warpage and distortion, which can also be extended to acoustic absorption.

The MAgnet Design Explorer algorithm (MADE) for LTS, Hybrid or HTS toroidal and poloidal systems of a tokamak with a view to DEMO

The European Roadmap to Fusion Electricity (Federici et al., 2018) [1] details the path to complete within the next three decades the DEMOnstration power plant, DEMO, aiming to a net gain of Energy Q=40. The 2018 DEMO baseline considers a 2 GW tokamak device, a target performance of 6 T on the plasma, with a major radius of 9 m. Considering the plasma aspect ratio and elongation, and the radial build of the thermal shield, the outer radius of the TFC inner leg is about 4.3 m. In the current designs, the TFC winding pack operates in a range of B = 12−13 T and is based on low temperature superconductors (LTS). As an alternative, High Temperature Superconductors (HTS) could be employed to extend the coil operation beyond the typical J/T/B range of Nb3Sn. The rationale behind the exploration of a fully HTS or Hybrid HTS/LTS design of the TFC Winding Pack (WP) is twofold: on the one hand, it is possible to maintain the target performance of the machine redesigning the radial build of each magnet as a function of a more efficient cable in terms of critical current density; on the other hand, it is possible to keep the machine power constant, increasing the field on the plasma axis, and consequently define a new radial build.This work presents and describes a combined algorithm implemented to enhance the DEMO magnet systems and optimize the DTT central solenoid, capable of accounting for the main electromagnetic and structural constraints, and consistently reshape the machine.

An energy-saving composite textile for thermal management

To reduce energy consumption, personal thermal management device has attracted great attention. Developing flexible fibers with low thermal conductivity or low emissivity is crucial but is still a great challenge. In this work, we developed a flexible and versatile composite textile with excellent passive and active heating capabilities. Via designing of the pore morphology and solid phase network, the aerogel textile of TPU/SiO2 (named as T-textile) is obtained with a low thermal conductivity of 0.037 W/mK. The T-textile also exhibits high flexibility with a fracture strain of 580%, while the low ductility is usually an issue for aerogel textures. Meantime, the conductive textile of TPU/Ag (S-textile) is fabricated with a low infrared emissivity of 0.40 and a high electric conductivity of 248.99 S/mm. The S-textile also possesses excellent electromagnetic shielding capability (above 75 dB). The simulated skin (∼27.4 °C) covered with layers of ST (S + T) and STT (S + T + T) textiles could be warmed to 32.6 °C and 35 °C, respectively. Also, with only 0.6 V, the simulated skin covered with S-textile could be heated to 50 °C, while with the TS textile (the ST textile flipped), it is 58 °C. The composite textile offers a combined solution for thermal insulation, Joule heating, flexibility, breathability and electromagnetic shielding capability, making it a smart personal thermal management device for complex scenarios.

Multifunctional silk textile composites functionalized with silver nanowires

AbstractThe low electrical conductivity of silk textile structures is a crucial factor limiting their practical applications. Silk‐based materials need modifications with different electroconductive compounds and structures. This report presents functionalization with silver nanowires (AgNWs) using polydopamine (PDA) as a linker. AgNWs create 3 and 10 g/m2 conductive networks on silk fabric. The surface resistance is estimated to be 1.5 × 105 Ω and 1.0 × 103 Ω, while volume resistance is 2.3 × 103 Ω and 6.8 × 102 Ω respectively to less and more developed AgNWs networks. AgNWs‐coated silk fabric is more thermally stable and provides thermal shielding. AgNWs functionalization makes silk fabric more hydrophilic due to PDA and polyvinylpyrrolidone (PVP) influence. PVP acts as a capping agent during AgNWs synthesis and remains on their surface. Silk fabric functionalized with AgNWs reveals above 99.94% reduction of bacterial growth against Gram‐positive and ‐negative bacteria Staphylococcus aureus and Klebsiella pneumoniae, respectively. The bacteriostatic and biocidal coefficients are respectively above 7.2 and 3.3 for both bacteria types. AgNWs do not harmfully influence excellent silk mechanical properties. The specific strength does not change significantly and the elongation at break is even improved. The presented AgNWs functionalized silk fabric has useful physical, antimicrobial, and electronic properties for designing multimodal textile products.

Flexible, breathable, and reinforced ultra-thin Cu/PLLA porous-fibrous membranes for thermal management and electromagnetic interference shielding

Electromagnetic interference shielding and thermal management by wearable devices show great potential in emerging digital healthcare. Conventional metal films implementing the functions must sacrifice either flexibility or permeability, which is far from optimal in practical applications. In this work, an ultra-thin (15 µm), flexible, and porous Cu/PLLA fibrous membrane is developed by depositing copper particles on the polymer substrate. With novel acetone & heat treatment procedure, the membrane is considerably stronger while maintaining the porous fibre structure. Its fantastic breathability and super high electrical conductivity (9471.8130 S/cm) enable the composites to have fast electrical heating characteristics and excellent thermal conductivity for effective thermal management. Meanwhile, the porous polymer substrate structure greatly enhances the diffusion of conductive substances and increases the electromagnetic interference shielding effectiveness of the membranes (7797.98 dB cm2/g at the H band and 8072.73 dB cm2/g at the Ku band respectively). The composites present high flexibility, breathability, and strength with the functions of thermal management and electromagnetic shielding, showing great potential for future portable electronic devices and wearable integrated garments.

Thermal design and performance of low beta cryomodule for CAFe

China initiative Accelerator Driven System (CiADS) has developed several kinds of cryomodules for superconducting proton linac at IMP. The low beta cryomodules had been designed, fabricated, assembled, and tested for the linac. To meet the requirements of minimizing heat transfer and operational stability, the thermal design and performance of low beta cryomodules have been studied. In this paper, finite element analysis and numerical calculation have been carried out on the design of important components such as thermal insulating support, bellows, thermal shield, power coupler, current leads and so on. Then the heat loads at various temperature levels have been summarized. Besides, the performance of the cryomodules including the cool down, equipment operating data, and heat load measurements are reported. The trial test result of low beta cryomodules shows that the various technical indexes satisfied the technical requirements.

Czochralski (CZ) process modification with cooling tube in the response to market Global silicon shortage

Recently, the silicon wafer producers, affected by Covid-19 and USA-China competition, looks for new production processes to increase the production. On the other hand, the common parts of CZ puller such as heater, crucible and thermal shield are optimized over time and now the common CZ process is reached to limitation for further improvement. Here, we propose a modified CZ method by adding a cooling tube into the growth zone. The new proposed Cz method is applied to the 8″ crystal growth process. A fully 3D transition model including energy equation, Navier–Stokes equation, surface-to-surface radiation heat transfer, moving mesh and thermal stress equations is implemented. The simulation is performed for both original and new CZ method. It was proved that the new CZ method increases the pulling speed up to 25 %. To ensure about the crystal quality, the thermal stress is compared between original and new proposed CZ method. Although it was found that the thermal stress increases about twice but still the maximum von Mises stress never exceeds the critical value 25 MPa. Additionally, the power consumption is also found to enhance maximum 2 kW under new conditions. To evaluate the model the interface and heater power for the original CZ puller is compared with industrial CZ process and it shows acceptable accuracy.

Thermal and Electromagnetic Design of a Superconducting Coil

This article presents the methodology followed for the thermal and electromagnetic design of a superconducting coil at the University of Western Macedonia, Kozani, Greece, aimed to be used in a unique superconducting magnetic energy storage system for laboratory education and research purposes. First, we discuss the design constraints of the coil and select its dimensions using both the electromagnetic finite element method (FEM) and analytical equations based on the available length of a YBCO high-temperature superconductor. Then, we select the position of the coil inside a vacuum chamber. Then, an initial experiment without thermal load is performed to measure the cooling characteristics of the cryocooler. Using the results of the experiment and employing thermal FEM, we obtain an approximation of the cryocooler's cooling power versus time. After placing the coil and the thermal shield in the selected position inside the chamber, we carried out an experiment to measure the cooling curve with the load attached. The cryocooler's cooling power is approximated using the same FEM procedure. Thus, for this specific thermal load, the behavior of the apparatus is known. The methodology followed for the design of this unique system can be easily replicated by other researchers.

Thermal Ablation Experiments of Carbon Phenolic and SiC-Coated Carbon Composite Materials Using a High-Velocity Oxygen-Fuel Torch

For future spacecraft TPS (heat shield) applications, ablation experiments of carbon phenolic material specimens with two lamination angles (0° and 30°) and two specially designed SiC-coated carbon-carbon composite specimens (with either cork or graphite base) were conducted using an HVOF material ablation test facility. The heat flux test conditions ranged from 3.25 to 11.5 MW/m2, corresponding to an interplanetary sample return re-entry heat flux trajectory. A two-color pyrometer, an IR camera, and thermocouples (at three internal locations) were used to measure the specimen temperature responses. At the 11.5 MW/m2 heat flux test condition, the 30° carbon phenolic specimen's maximum surface temperature value is approximately 2327 K, which is approximately 250 K higher than the corresponding value of the SiC-coated specimen with a graphite base. The 30° carbon phenolic specimen's recession value is approximately 44-fold greater, and the internal temperature values are approximately 1.5-fold lower than the corresponding values of the SiC-coated specimen with a graphite base. This indicates that increased surface ablation and a higher surface temperature relatively reduced heat transfer to the 30° carbon phenolic specimen's interior, leading to lower internal temperature values compared to those of the SiC-coated specimen with a graphite base. During the tests, a phenomenon of periodic explosions occurred on the 0° carbon phenolic specimen surfaces. The 30° carbon phenolic material is considered more suitable for TPS applications due to its lower internal temperatures, as well as the absence of abnormal material behavior as observed in the 0° carbon phenolic material.

Self-healable and super-stretchable conductive elastomeric nanocomposites for efficient thermal management characteristics and electromagnetic interference shielding

Due to the pressing need to mitigate current electromagnetic wave pollution (connecting to the 5 G era), lightweight, stretchable, thermally, and electrically conductive nanocomposite materials have attracted significant scientific interest. Herein, self-healable carboxylated nitrile butadiene elastomeric (XNBR) based nanocomposites were fabricated via sequential wet cum melt mixing technique utilizing multi-walled carbon nanotubes (MWCNTs). The metal-ligand complexes in the XNBR elastomer chain endow a reversible network that leads to self-healing ability. The higher aspect ratio of MWCNTs assists in constructing interconnected conductive pathways inside the XNBR matrix. The nanocomposite with MWCNTs (15 phr) provided an excellent EMI shielding effectiveness of − 27.4 dB, whereas the nanocomposite exhibited a thermal conductivity of 0.85 W.m−1. K−1. Interestingly, the interconnected networking pathway of MWCNTs in the XNBR matrix prepared a tunable analogical structure providing an absorption-dominant shielding mechanism. Under severe practical and environmental testing conditions, the nanocomposites showed a minute change in electromagnetic effectiveness, demonstrating their good performance for outdoor applications. These ultra-lightweight, self-healable, recyclable MWCNTs/ XNBR EMI shields are promising materials for next-generation super-stretchable and portable smart electronics.

Nuclear design of a shielded cabinet for electronics: The ITER radial neutron camera case study

The Radial Neutron Camera (RNC) is a diagnostic system located in ITER Equatorial Port #1 providing several spatial and time-resolved parameters for the fusion power estimation, plasma control and physics studies. The RNC measures the uncollided 14 MeV and 2.5 MeV neutrons from deuterium-tritium (DT) and deuterium-deuterium (DD) fusion reactions through an array of neutron flux detectors located in collimated Lines of Sight. Signals from RNC detectors (fission chambers, single Crystal Diamonds and scintillators) need preamplification because of their low amplitude. These preamplifiers have to be as close as possible to the detectors in order to minimize signal degradation and must be protected against fast and thermal neutrons, gamma radiation and electromagnetic fields. The solution adopted is to host the preamplifiers in a shielded cabinet located in a dedicated area of the Port Cell, behind the Bioshield Plug. The overall design of the cabinet must ensure the necessary magnetic, thermal and nuclear shielding and, at the same, satisfy weight and allocated volume constraints and maintain its structural integrity. The present paper describes the nuclear design of the shielded cabinet, performed by means of 3D particle transport calculations (MCNP), taking into account the radiation streaming through the Bioshield penetrations and the cross-talk effect from the neighboring Lower and Upper Ports. We present the assessment of its nuclear shielding performances and analyze the compliancy with the alert thresholds for commercial electronics in terms of neutron flux and cumulated ionizing dose.