Radiation-resistant Properties Research Articles

Characterization of a diamond detector during experiments under wide energy spectrum neutrons

The detection of wide energy spectrum neutrons is important in nuclear data measurement and nuclear physics. Diamond detectors play a significant role in experiments based on wide energy spectrum neutron beams due to the excellent radiation resistance and electrical properties. In usage, the polarization effect and pumping effect of diamond detectors can significantly influence the stability of the diamond detector. For the first time, we conducted a comprehensive characterization of the performance of a diamond detector under wide energy spectrum neutrons irradiation by extracting and analyzing key parameters including Pulsewidth, Peakmax, Qcal, and count rate. This work provides a technical procedure for assessing the stability of diamond detectors in complex radiation fields. Signals of different time-of-flight (ToF) can be selected based on the experimental objective, allowing for the observation of the stability of parameters of interest, such as Qcal and count.

Swift heavy ion irradiation effects on tungsten carbide films

Tungsten carbide (WC) is an important material to study for various applications in extreme environments due to its radiation-resistant properties and high mechanical strength. Due to its excellent properties such as high hardness, strength, and wear resistance, it is also being considered lately as a plasma facing component in nuclear fusion reactors. To study the response of this material in extreme radiation environments, WC films prepared using RF sputtering technique were irradiated with 100 MeV Ag8+ ions in the present work. The irradiation was carried out at three different fluences: 3 × 1012, 1 × 1013, and 3 × 1013 ions/cm2. Rutherford Backscattering Spectrometry (RBS) was performed to determine the stoichiometry and thickness of the pristine film. To study the irradiation-induced modifications, glancing angle X-ray diffraction (GAXRD), field emission scanning electron microscopy (FE-SEM), High Resolution Transmission Electron Microscopy (HRTEM), and Raman spectroscopy were performed on the pristine and irradiated samples. GAXRD of the pristine and irradiated samples revealed grain size reduction accompanied with reduced crystallinity with increasing ion fluence which was further manifested in HRTEM measurements and Raman spectroscopy measurements. Change in surface morphology due to the ion irradiation was observed in FE-SEM. These modifications have been explained using thermal-spike and TRIM simulations which showed that although the swift heavy ions irradiation did not result in track formation in the WC films, it caused radiation damage which may be attributed to the synergistic effect of electronic and nuclear energy loss mechanisms. These results might be crucial for a fundamental understanding of the radiation resistance of WC thin films and its application in different radiation environments.

Threshold displacement energies and primary radiation damage in AlN from molecular dynamics simulations

Aluminum nitride (AlN) is an attractive material for sensing application in radiation environments owing to its radiation resistance, optical wide-bandgap, and piezoelectric properties. Yet, the variations of its physical properties under exposure to energetic particle needs to be better understood. Here, we report the results of the molecular dynamics simulations of the structural changes in AlN under irradiation via the knock-on atom technique. By creating and evolving irradiation cascades due to energetic particle interactions with the atoms of the crystalline lattice, we determine the rate of defect production as a function of the deposited energy. Further, we determine the threshold displacement energy, a key characteristic that describes how efficient the defect production in the given material is. We find that displacement threshold is slightly greater than isostructural gallium nitride and is lower than metal oxides used in radiation environments.

Silicon carbide single crystals for high-temperature supercapacitors.

Designing advanced electrode materials that can be reliably cycled at high temperatures and used for assembling advanced energy storage devices remain a major challenge. As a representative of novel wide bandgap semiconductors, silicon carbide (SiC) single crystals have broad prospects in high-temperature energy storage due to their excellent characteristics such as low thermal expansion coefficient, high temperature radiation resistance and stable chemical properties. In this work, an N-type SiC single-crystal material with a high-density porous structure was successfully designed and prepared by using an improved electrochemical anodic oxidation strategy. Besides, the N-type SiC single crystals were used in electrochemical energy storage as an integrated electrode material, exhibiting superior electrochemical performance. In addition, the high-temperature supercapacitor device assembled with ionic liquids has a wide operating temperature range and maintains a capacity of 88.24% after 5000 cycles at 150 °C. The reasons for its high energy storage performance are discussed through electrochemical tests and first-principles calculation methods. This study proves that the application of SiC single crystals in supercapacitor devices has great potential in the field of high-temperature energy storage, providing a reference for the further development of novel semiconductors in the field of energy storage and optoelectronic devices.

Selective Separation of Zr(IV) from Simulated High-Level Liquid Waste by Mesoporous Silica.

The efficient separation of Zr(IV) ions from strong acidic and radioactive solutions is a significant challenge, especially in the context of the aqueous reprocessing of nuclear fuels. The complexity of such solutions, which are often characterized by high acidity and the presence of radioactive elements, poses formidable challenges for separation processes. Herein, several mesoporous silicas (HMS, MCM-41, KIT-6, and SiO2-70 Å) with excellent acid and radiation resistance properties were employed as sorbents to remove Zr(IV) ions from simulated high-level liquid waste. The batch experiments were designed to investigate the influence of adsorption time, HNO3 concentration, initial Zr(IV) concentration, adsorbent dosage, and temperature on the adsorption behavior of Zr(IV). The results indicate that the adsorption equilibrium time of mesoporous silica materials was approximately 8 h, and all the adsorption processes followed the pseudo-second-order kinetics equation. The isotherms of Zr(IV) adsorption by KIT-6 exhibited good agreement with the Langmuir model, while the Freundlich model could be utilized to fit the adsorption on HMS, MCM-41, and SiO2-70 Å. The adsorption capacity of MCM-41 for Zr(IV) in 3 mol/L HNO3 was 54.91 mg/g, which is three times the adsorption capacity reported for commercial silica gel (17.91 mg/g). The thermodynamic parameters indicate that the adsorption processes for zirconium are endothermic reactions. Furthermore, the mesoporous silicas exhibited a pronounced selectivity in the adsorption of Zr(IV) within a simulated high-level liquid waste containing 10 co-existing cations (3 mol/L HNO3). This suggests that mesoporous silicas have great potential for Zr(IV) removal in actual radioactive liquids with high acidity during spent fuel reprocessing.

Accelerated design of low-activation high entropy alloys with desired phase and property by machine learning

Low-activation high-entropy alloys (HEAs) have been regarded as novel candidate structural materials for fusion reactors due to their excellent mechanical and radiation resistant properties. Nevertheless, the potential vast composition space brings a prominent challenge in the design of low-activation HEAs. Herein, a new strategy based on machine learning (ML) was proposed to accelerate the exploitation of low-activation HEAs with desired phase and property. Two optimized classification models with accuracy of > 85% were developed to identify single-phase body-centered-cubic (BCC) solid-solution (SS) HEAs. One regression model with correlation coefficient (R) of > 0.9 was constructed to predict the hardness of HEAs. The phase and hardness prediction models were combined in accordance with an integrated design strategy to identify the low-activation HEAs with desired phase and property from 284,634 candidates. With this design strategy, a new desired single-phase BCC Fe35Cr30V20Mn10Ti5 low-activation HEA with 555.9 ± 15.3 HV was designed and fabricated via only two experimental iterations. Besides, two new phase selection rules with accuracy of > 95% were given to efficiently screen SS and BCC HEAs, respectively. Our research work not only provides new ideas to search for low-activation HEAs, but also can be extended to the integrated design of structure and performance of other advanced materials.

Exploring critical behavioral differences in physical, structural, and nuclear radiation attenuation properties of produced High Entropy Alloy (HEA) and Refractory-High Entropy Alloy (RHEA) samples

Refractory-High entropy alloys (RHEAs) are known for their exceptional mechanical and radiation-resistant properties, making them promising materials for use in nuclear reactors. Their high entropy composition, which consists of multiple elements in roughly equal proportions, can create a stable microstructure that withstands high levels of radiation damage. The objective of this work is to further our comprehension of the unique behavioral, physical, structural, and nuclear radiation attenuation characteristics shown by High-Entropy Alloys (HEA) and Refractory-High entropy alloy (RHEA) materials. Accordingly, two high entropy alloy (HEA) samples through two different compositions were produced. The first composition under consideration is the typical high-entropy alloy (HEA) defined as MnCrFeNiCoMo0.5. The second composition under consideration is a refractory high entropy alloy (RHEA) characterized by the following elemental composition: TiZrNbHfVTa0.1. SEM and EDX analyses were conducted in terms of determining their physical and structural attributes. Next, a133Ba radioisotope together with a HPGe detector were utilized for gamma-ray transmission experiments. Finally, a241Am/Be source and a gas proportional detector were used for neutron absorption experiments for HEA and RHEA samples. The alloy structures displayed a unique degree of uniformity. Throughout the RHEA phase, the incorporation of refractory elements did not provide any discernible adverse impacts on the physical stability. The counting spectrum provided a clear explanation of the gamma ray absorption features shown by the RHEA (R) sample, highlighting its exceptional absorption properties. Regarding the absorption properties of neutrons, it was observed that RHEA had a comparatively reduced amount of absorption. Therefore, it can be concluded that the basic structure of RHEA grants it superior gamma-ray attenuation qualities compared to HEA. It can be concluded that RHEA demonstrates superior applicability as a material in comparison to HEA, especially in situations involving the use of fuel rods, where maintaining of neutron quantity has paramount importance for achieving optimum neutron activation.

Research and Application Progress of High-Entropy Alloys

With the continuous improvement of global technological levels and the increasing demand for high-performance alloy materials in national economic construction, the traditional single principal component alloy is increasingly unable to meet people’s increasing service needs. High-entropy alloys play an important role in aerospace, mechanical manufacturing, biomedicine, energy development and other engineering fields because of their unique physical, chemical and mechanical properties. Based on the concept of high-entropy alloys, the high-entropy effect, lattice distortion effect, sluggish diffusion effect and cocktail effect of high-entropy alloys are represented in this paper. The common preparation methods of high-entropy alloys are summarized according to the classification of melting-casting method, mechanical alloying method and coating method. The strength and toughness, wear resistance, corrosion resistance, high temperature resistance, fatigue resistance, radiation resistance and magnetic properties of the high-entropy alloys are discussed. The application prospect of high-entropy alloys is summarized, and the future research and development direction of high-entropy alloys are prospected on this basis.

Atomic Insights into the Structural Properties and Displacement Cascades in Ytterbium Titanate Pyrochlore (Yb2Ti2O7) and High-Entropy Pyrochlores

Pyrochlore oxides (A2B2O7) are potential nuclear waste substrate materials due to their superior radiation resistance properties. We performed molecular dynamics simulations to study the structural properties and displacement cascades in ytterbium titanate pyrochlore (Yb2Ti2O7) and high-entropy alloys (HEPy), e.g., YbYTiZrO7, YbGdTiZrO7, and Yb0.5Y0.5Eu0.5Gd0.5TiZrO7. We computed lattice constants (LC) (ao) and threshold displacement energy (Ed). Furthermore, the calculation for ao and ionic radius (rionic) were performed by substituting a combination of cations at the A and B sites of the original pyrochlore structure. Our simulation results have demonstrated that the lattice constant is proportional to the ionic radius, i.e., ao α rionic. Moreover, the effect of displacement cascades of recoils of energies 1 keV, 2 keV, 5 keV, and 10 keV in different crystallographic directions ([100], [110], [111]) was studied. The number of defects is found to be proportional to the energy of incident primary knock-on atoms (PKA). Additionally, the Ed of pyrochlore exhibits anisotropy. We also observed that HEPy has a larger Ed as compared with Yb2Ti2O7. This establishes that Yb2Ti2O7 has characteristics of lower radiation damage resistance than HEPy. Our displacement cascade simulation result proposes that HEPy alloys have more tendency for trapping defects. This work will provide atomic insights into developing substrate materials for nuclear waste applications.

Investigation of the Radiation Resistance and Optical Properties of New Composite Thermal Barrier Coatings

Investigation of the Radiation Resistance and Optical Properties of New Composite Thermal Barrier Coatings

Research Progress of ODS FeCrAl Alloys-A Review of Composition Design.

After the Fukushima nuclear accident, the development of new accident-tolerant fuel cladding materials has become a research hotspot around the world. Due to its outstanding corrosion resistance, radiation resistance, and creep properties at elevated temperatures, the oxide dispersion strengthened (ODS) FeCrAl alloy, as one of the most promising candidate materials for accident-tolerant fuel cladding, has been extensively studied during the past decade. Recent research on chemical composition design as well as its effects on the microstructure and mechanical properties has been reviewed in this paper. In particular, the reasonable/optimized content of Cr is explained from the aspects of oxidation resistance, radiation resistance, and thermal stability. The essential role of the Al element in oxidation resistance, high-temperature stability, and workability was reviewed in detail. The roles of oxide-forming elements, i.e., Y (Y2O3), Ti, and Zr, and the solid solution strengthening element, i.e., W, were discussed. Additionally, their reasonable contents were summarized. Typical types of oxide, i.e., Y-Ti-O, Y-Al-O, and Y-Zr-O, and their formation mechanisms were also discussed in this paper. All aspects mentioned above provide an important reference for understanding the effects of composition design parameters on the properties of nuclear-level ODS FeCrAl alloy.

Structure, stability and defect energetics of interfaces formed between conventional and transformed phases in Cu–Nb layered nanocomposite

Layered nanocomposite material having fcc-bcc interface with Kurdjumov-Sachs interface orientation relation has shown great potential as radiation resistant structural material for future fusion energy reactors. The superior radiation resistant properties of this material are attributed to it’s special fcc-bcc interface structure. In this study we have reported a stable interface between conventional bcc phase of Nb and transformed bcc phase of Cu. This bcc-bcc interface is found to be stable from both strain-energy and dynamical stability analysis. We have also shown that the bcc-bcc interface has different defect energetics behaviour compared to previously reported fcc-bcc interface which has a negative impact on the self annihilation property of the material against radiation induced defects. These aspects should be carefully considered in the future design of robust layered material for extreme radiation environment.

MECHANICAL STUDY OF 9Cr-316SS-1Mo MATERIALS FOR NUCLEAR FUEL CLADDING MATERIALS POWER REACTORS

Cladding or cladding used for nuclear fuel elements requires special requirements such as good mechanical properties, radiation resistance, corrosion resistance, adequate physical and chemical properties, and low thermal neutron absorption. Materials that are widely used as structural materials for nuclear reactors are beryllium, magnesium, aluminum, zirconium and their alloys. Alloy 9Cr-316-1Mo as Nuclear fuel cladding material. 9Cr-316-1Mo material has been made. The material 9Cr-316-1Mo was chosen as an alternative cladding material because it has good mechanical and chemical properties with a microscopic cross-section of 2.6 barn. At first, the 9Cr-316-1Mo sample was cast withThe composition is 90% 316L Stainless Steel, 9% Chromium (Cr) and 1% Molybdenum (Mo) is added using an electric arc. After casting the alloy,the composition of 9Cr-316-1Mo was tested without heating and then given heat treatment (tempering) starting from 100 0C, 200 0C, 300 0C, 400 0C and 500 0C and allowed to stand for 60 minutes, then tested for hardness (rockwell) , Impact testing, micro structure testing and Chemical composition testing (XRF). The results of the Rockwell hardness test obtained the highest hardness value in the sample without tempering, namely 20.66 HRc and the lowest hardness value in the sample with tempering 500 0C, namely 16.33 HRc. Then the impact test results obtained the highest impact energy value in the sample with tempering 100 0C, which is 0.9996 Joule/mm2 and the lowest impact energy value in the sample with tempering 500 0C, which is 0.9962 Joule/mm2. The results of the microstructure test showed that the structure of 9Cr-316-1Mo still contained ferrite, pearlite and martensite. The testing process is still not fully completed and will be reported later.

Downregulation of CEMIP enhances radiosensitivity by promoting DNA damage and apoptosis in colorectal cancer.

Colorectal cancer (CRC) is the third leading malignancy worldwide in both new cases and deaths. Neoadjuvant radiotherapy is the standard preoperative regimens for locally advanced patients. However, approximately 50% of patients develop recurrence and metastasis after radiotherapy, which is largely due to the radiation resistance properties of the tumor, and the internal mechanism has not been elucidated. Here we found that CEMIP expression is up-regulated in a variety of tumor types, particularly in CRC. Public databases and clinical samples revealed that CEMIP expression is significantly higher in tumor tissues than in adjacent normal tissues in patients with locally advanced CRC who received neoadjuvant chemoradiotherapy, and it is closely related to the poor prognosis. Functional characterization uncovered that downregulation of CEMIP expression can enhance the radiosensitivity of CRC cells, which is confirmed to be achieved by promoting DNA damage and apoptosis. In vivo studies further verified that CEMIP knockdown can significantly improve the radiosensitivity of subcutaneously implanted colorectal tumors in mice, suggesting that CEMIP may be a radiation-resistant gene in CRC. Mechanistically, EGFR/PI3K/Akt signaling pathway is hypothesized to play a key role in CEMIP mediating radiation resistance. These results provide a potential new strategy targeting CEMIP gene for the comprehensive treatment of locally advanced CRC patients.

The Retrospect and Prospect of GaN-Based Schottky Diode

In the 21st century, with the continuous progress of human society and the continuous upgrading of the integrated circuit industry in recent years, the rapid development of modern science and technology makes us have higher and higher requirements for semiconductor products in our life and production. Compared with the first generation and the second generation of semiconductors, the third generation of semiconductors represented by GaN relies on its high electron mobility, bandgap width, electron saturation speed, high-temperature resistance, radiation resistance, and other suitable material properties. It has more and more extensive application prospects in the research field of microwave high-power devices. Today, the introduction of semiconductors in electronics improves the energy efficiency of equipments and modules. Gallium nitride (GaN) - based schottky diodes have broad application prospects in the next generation of schottky diodes due to their excellent performance. However, because of some technical concerns, these materials have not been fully developed. This work briefly summarized some science and technology related to GaN-Based Schottky Diode. A special focus will be put on the advantages and disadvantages of GaN-Based Schottky Diode, discussing some modern improved designs. Finally, possible breakthroughs of GaN-Based Schottky Diode will be summarized.

Shape memory polyimides and composites with tunable chain stiffness and ultrahigh transition temperature range

Shape memory polymer has shape morphing capabilities upon external stimuli, including thermal-, electro-, magnetic-, photo-, and so on. Among them, shape memory polyimide (SMPI) has excellent thermal stability, creep resistance, radiation resistance, and good mechanical properties, which can be applied in various fields. In this paper, 5-amino-2-(4-aminophenyl) benzimidazole, 2-(4-aminophenyl) benzoxazol-5-amine, and 3,3′,4,4′-biphenyltetracarboxylic dianhydride are utilized to synthesize two semi-trapezoidal aromatic heterocyclic SMPIs with tunable chain stiffness, including imidazole-based shape memory polyimide (M-SMPI) and oxazole-based shape memory polyimide (E-SMPI). Because of asymmetric imidazole groups, M-SMPI has the highest SMPI transition temperature in the world, at 416 ℃. Additionally, the M-SMPI/CF composite also has the highest SMPIC (shape memory polyimide composite) transition temperature, at 399 ℃. Thus, M-SMPI and M-SMPI/CF composites can be used as smart materials in deformable flexible electrodes, high temperature aerospace devices and deployable structures.

Recent Trends in Magnetic Polymer Nanocomposites for Aerospace Applications: A Review.

Polymers have had an enormous impact on science and technology, and their interest relating to the development of new macromolecular materials has exponentially increased. Polymer nanocomposites, materials based on a polymeric matrix covalently coupled to reinforcement, display properties of both components. In the aerospace industry, polymer nanocomposites are attractive due to their promising characteristics, among which lightness, mechanical and thermal resistance, radiation and corrosion resistance, and conductive and magnetic properties stand out. The use of them, instead of metal-based materials, has allowed the optimization of design processes and applications in order to provide safer, faster, and eventually cheaper transportation in the future. This comparative review collects the most relevant and prominent advances in the development of polymer nanocomposites with aerospace applications starting from basic aspects such as the definition of polymer nanocomposite to more specialized details such as synthesis, characterization, and applications, in addition to proposing new research branches related to this topic.

Effects of the ionizing irradiation of γ-rays, X-rays, and UV-rays on the optical properties of Ag-contained/Ag-free photo-thermo-refractive glass

To simulate the effects of ionizing irradiation on photo-thermo-refractive (PTR) glass in a cosmic environment, the optical properties changes under ionizing irradiation (γ-, X- and UV-ray) were investigated on PTR-glass with and without Ag doped (named as PTR-S and PTR-F, respectively) samples. Thermoluminescence (TL), transmission electron microscopy (TEM) measurements, UV-VIS absorption spectroscopy analysis, Gaussian peak fitting, and continuous wave electron paramagnetic resonance (CW-EPR) were used to determine the species of the irradiation-induced color centers. The radiation resistance properties of the Ag-species on the PTR-S glass were evaluated by comparing the defect center concentrations in the irradiated PTR-S and PTR-F glasses. The results showed that absorption in PTR-F and PTR-S glass increased significantly with increasing γ-irradiation dose, which was related to HC1, HC2, E′, L, ETC defect centers and Ag-species, and the formation of HC1, HC2, E’, and L-centers was reduced by the doping of Ag into the PTR-S glass matrix. Compared with the γ-irradiation, X-irradiation showed a similar effect. In comparison, UV-irradiation induced fewer defect centers and smaller Ag (NPs). This discrepancy could be caused by variations in photon energies.

The Shape Memory Properties and Actuation Performances of 4D Printing Poly (Ether-Ether-Ketone).

Shape-memory polymers (SMPs) have gradually emerged in the mechanism and biomedical fields and facilitate the upgrading of industrial mechanisms and the breakthrough of technical bottlenecks. However, most of the SMPs are infeasible in harsh environments, such as aerospace, due to the low glass transition temperature. There are still some works that remain in creating truly portable or non-contacting actuators that can match the performances and functions of traditional metal structures. Polyether-ether-ketone (PEEK) with a high glass transition temperature of 143 °C is endowed with outstanding high-temperature resistance and radiation-resistant properties and shape memory behavior. Thus, we explore the shape-memory properties and actuation performances of high-temperature PEEK in bending behaviors. The shape-recovery ratio, actuation speed and force under different programming conditions and structure parameters are summarized to complete the actuation capacities. Meanwhile, a metallic ball transported by shape-memory PEEK and deployed drag sail with thermo-responsive composite joints were shown to verify the potential in aerospace.

Thermal stability of gamma irradiated ethylene propylene diene monomer composites for shielding applications

AbstractThe effect of gamma‐irradiation on the ethylene propylene diene monomer (EPDM) based composites, loaded with tungsten and barium sulfate were investigated for radiation resistance properties. The tungsten and barium sulfate fillers were added in different proportion (wt%) to EPDM matrix and prepared using compression molding technique. The developed EPDM composites were exposed to 60Co gamma radiation doses from 0 to 400 kGy. The swelling index of the composites were studied for the irradiated samples and found to decrease with higher gamma doses. Tensile characterization was also carried out and elongation at break, tensile strength and modulus at 100% elongation have been determined for gamma irradiated EPDM based composites. Tensile properties were modified in the irradiated samples and elongation at break is decreased whereas the modulus increases as a function of gamma dose due to increases in crosslinking after irradiation. Thermogravimetric analysis was performed and observed improvement in thermal stability of gamma irradiated EPDM composites.