Effect Of Pre-irradiation Research Articles

Discerning the effect of various irradiation modes on the corrosion of Zircaloy-4

Using proton irradiation, this study investigates the individual influence of several factors on the corrosion kinetics of Zircaloy-4 in a hydrogenated water environment simulating a Pressurized Water Reactor (PWR). Using both simultaneous irradiation-corrosion and autoclave corrosion, we separately examine (i) the effect of pre-irradiation on modifying the structure of the material, (ii) the impact of irradiation on creating defects in the growing oxide layer during corrosion, and (iii) the influence of irradiation on increasing the corrosion potential through radiolysis during corrosion. To replicate the neutron-irradiated microstructure, two proton pre-irradiation schedules were employed: Schedule 1 (isothermal irradiation at 350°C to 5 dpa) to simulate high-temperature PWR conditions, and Schedule 2 (two-step process: irradiation to 2.5 dpa at -10°C followed by 2.5 dpa at 350°C) to simulate lower temperature PWR and Boiling Water Reactor (BWR) conditions. Long-term autoclave corrosion testing for 360 days at 320°C revealed no significant difference between unirradiated samples and those pre-irradiated according to either schedule, with all samples exhibiting sub-cubic kinetics within the pre-transition regime. Pre-irradiated samples underwent Simultaneous Irradiation Corrosion (SIC) tests, corroding in 320°C water while being irradiated with protons. Corrosion was found to accelerate in all SIC-tested samples relative to autoclave conditions, with the greatest increase observed in non-pre-irradiated regions of the samples. Pre-irradiation with either schedule resulted in a slower corrosion rate compared to non-pre-irradiated regions under SIC conditions. The degree of radiolysis observed in the SIC tests surpassed typical PWR conditions, approaching levels found in BWRs. Radiolysis products were identified as a primary contributors to accelerated corrosion, corroborated by radiolysis bar tests. These findings underscore the intricate interactions between irradiation, corrosion, and water chemistry in determining Zircaloy-4 corrosion kinetics within nuclear reactor environments.

Effect of Near-Infrared Pre-Irradiation on Irreversible Electroporation Treatment of Rat Gastric Tissues

Irreversible electroporation (IRE) is a recognized ablation technique that induces apoptosis via potent electric fields. Nonetheless, the heterogeneity of biological tissues often results in inconsistent treatment outcomes, leaving residual viable cells and leading to potential relapse. To address this, previous strategies incorporated chemical enhancers to IRE, but these faced limitations such as limited tissue diffusion and hyperpigmentation. In this study, we explore the synergistic application of near-infrared (NIR) irradiation with IRE. Using an in vivo rat gastric tissue model, we pre-irradiated samples with NIR at 3 J/cm2 prior to IRE. The combined treatment, termed NIRE, produced a change in tissue impedance of 13.5 Ohm compared to IRE alone, indicating NIR’s potential in modulating tissue electrical properties. Subsequent histopathological and molecular assessments revealed a 1.12-fold increase in apoptosis for NIRE over IRE. Notably, the apoptosis-related proteins BCL and p21 exhibited a 1.24-fold and 1.29-fold overexpression following NIRE treatment, respectively, emphasizing NIRE’s enhanced apoptotic activation. In essence, our findings underscore the augmented therapeutic efficacy of IRE when complemented with NIR, presenting a promising avenue for bolstering treatment outcomes in tissue ablation.

Pre-irradiation effects of ectoine on radiation-induced cardiotoxicity in female Swiss albino mice model

Pre-irradiation effects of ectoine on radiation-induced cardiotoxicity in female Swiss albino mice model

Synergistic effects of gamma pre-irradiation and additional vulcanizing agent in case of ground tire rubber containing vulcanizates

In this study, we investigated gamma radiation treated ground tire rubber (GTR) at different doses and measured the soluble content and the cross-link density of the samples. These results have been evaluated with Horikx's diagram. The results showed that at low doses, the selective chain-scission of the sulphur cross-links is dominant; however, at higher doses, the degradation of the polymer backbone comes to the fore. Natural rubber (NR) based mixtures were prepared in an internal mixer using conventional and two-step mixing, then the samples were vulcanized. Synergistic effects were observed when using radiation treatment and two-step mixing, resulting in improved mechanical properties. In materials where only one treatment was applied, the properties did not change significantly. The morphology of the mixtures was observed using scanning electron micrographs, which showed that the GTR could integrate well into the matrix.

Synergistic Effects of Gamma Pre-Irradiation and Additional Vulcanizing Agent in Case of Ground Tire Rubber Containing Vulcanizates

Synergistic Effects of Gamma Pre-Irradiation and Additional Vulcanizing Agent in Case of Ground Tire Rubber Containing Vulcanizates

Effects of Mo/Zr addition on deuterium retention in W-Y2O3 alloys

Mo/Zr were added to further improve the mechanical properties of W-Y 2 O 3 alloys, thus improving W ductility due to the addition of Y 2 O 3 nanoparticles. Herein, the effects of minor addition of elemental Mo/Zr and Fe-ion pre-irradiation on D retention in W-Y 2 O 3 alloys were investigated. The maximal fluence of W-1 wt.%Mo-0.25 wt.%Y 2 O 3 and W-0.1 wt.%Zr-0.25 wt.%Y 2 O 3 samples irradiated with 5-keV-energy D 2 ions was 10 22 D 2 /m 2 , and Fe-ion pre-irradiation was performed at ion fluences of up to 4 × 10 18 /m 2 at the energy of 1 MeV. For both alloys, the D desorption amount increased with increasing D 2 -ion irradiation fluence, regardless of Fe-ion pre-irradiation. Compared with W-Y 2 O 3 , the overall amount of the D desorption increased for both alloys without Fe-ion pre-irradiation. However, it decreased for both alloys with Fe-ion pre-irradiation, when the D 2 -ion irradiation fluence was 10 22 D 2 /m 2 . The addition of Mo/Zr prevented the diffusion of D from the surface to the inside of the sample. Therefore, Fe-ion pre-irradiation had a negligible effect on D desorption in the Mo- or Zr-added W-Y 2 O 3 alloys. Changes in the microstructures of the W alloy owing to the addition of minor elements strongly affected the D desorption. The addition of Mo promoted the formation of dislocation loops during the D 2 -ion irradiation. In contrast, the addition of Zr refined the Y 2 O 3 particles. These defects served as D trapping sites, thereby weakening the pre-irradiation effect of Fe ions.

Effect of pre-irradiation on corrosion performance of beryllium in BEPC II/BES III and CEPC beam pipe

Beryllium is one of the most important materials in high energy physics and nuclear physics experiments. Beam pipe, which lies at the centre of the second-generation Beijing Electron Positron Collider (BEPC II) and its detector Beijing Spectrometer III (BES III), is made of beryllium and the electron–positron beam collision occurs in it. China is planning to build a Circular Electron Positron Collider (CEPC) with higher brightness, in which the beryllium beam pipe will inevitably be used. High-speed particles will produce a lot of γ-rays and neutron irradiation and heat loads on the beryllium beam pipe in the collision. In order to ensure the normal particle detection of BES III, a coolant must be used to take away the excess heat to maintain the constant temperature of the outer wall of the beam pipe. Researches, however, have shown that the coolant can cause some corrosion of beryllium and affect the normal operation of the beam pipe in the irradiation environment. Therefore, this paper intends to study the influences of different irradiation types and doses on the corrosion performance of beryllium in EDM-1, by using No.1 Electrical Discharge Machining Oil (EDM-1) to scour the beryllium sample after γ and neutron pre-irradiation, according to the working condition of BEPC II/BES III. It is found that pre-irradiation promotes the formation of pitting nuclei and corrosion holes on the beryllium surface. The corrosion effect of γ pre-irradiation on beryllium in EDM-1 is much more significant than that of γ and neutron pre-irradiation and the corrosion strengthens with the increase of irradiation dose. Impurity elements in beryllium play an important role in inducing pitting corrosion and promoting the formation and expansion of corrosion holes. S2− in EDM-1 may adsorb on the surface and further be oxidized to SO2 and SO42−, which can be incorporated into the oxide–metal interface and change its composition. In conclusion, irradiation enhanced the corrosion of beryllium in EDM-1.

Effect of UVC pre-irradiation on the Suwannee river Natural Organic Matter (SRNOM) photooxidant properties

The present study aimed to investigate the changes in the chemical composition, and in the optical and photooxidant properties of Suwannee River Natural Organic Matter (SRNOM) induced by UVC (254 nm) treatment. The extent of the photodegradation was first assessed by UV–visible/fluorescence spectroscopies and organic carbon analysis. An in-depth investigation of the chemical changes was also conducted using liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry after derivatizations. A series of mono, di and tricarbonyls and mono and dicarboxylic acids in C1C6 were identified in samples irradiated from 1 to 4 h. After 3 h of irradiation, carbonyls accounted for 46% of the organic carbon remaining in solution whereas carboxylic acids represented about 2%. Then, we investigated the modifications of the photooxidant properties of SRNOM induced by these chemical changes. At 254 nm, UVC pre-irradiated SRNOM photodegraded glyphosate 29 times faster than original SRNOM and the reaction was fully inhibited by 2-propanol (5 × 10−3 M). This enhanced photooxidant properties at 254 nm toward glyphosate was therefore reasonably due to •OH radicals formation, as confirmed by additional ESR measurements. A mechanism involving a chain reaction was proposed based on independent experiments conducted on carbonyl compounds, particularly pyruvic acid and acetone. The findings of this study show that UVC pre-treatment of NOM can enhance the removal of water pollutants and suggests a possible integration of a NOM pre-activation step in engineered water treatment sytems.

Effects of Radiation Intensity, Mineral Matrix, and Pre-Irradiation on the Bacterial Resistance to Gamma Irradiation under Low Temperature Conditions.

Ionizing radiation is one of the main factors limiting the survival of microorganisms in extraterrestrial conditions. The survivability of microorganisms under irradiation depends significantly on the conditions, in which the irradiation occurs. In particular, temperature, pressure, oxygen and water concentrations are of great influence. However, the influence of factors such as the radiation intensity (in low-temperature conditions) and the type of mineral matrix, in which microorganisms are located, has been practically unstudied. It has been shown that the radioresistance of bacteria can increase after their exposure to sublethal doses and subsequent repair of damage under favorable conditions, however, such studies are also few and the influence of other factors of extraterrestrial space (temperature, pressure) was not studied in them. The viability of bacteria Arthrobacter polychromogenes, Kocuria rosea and Xanthomonas sp. after irradiation with gamma radiation at a dose of 1 kGy under conditions of low pressure (1 Torr) and low temperature (−50 °C) at different radiation intensities (4 vs. 0.8 kGy/h) with immobilization of bacteria on various mineral matrices (montmorillonite vs. analogue of lunar dust) has been studied. Native, previously non-irradiated strains, and strains that were previously irradiated with gamma radiation and subjected to 10 passages of cultivation on solid media were irradiated. The number of survived cells was determined by culturing on a solid medium. It has been shown that the radioresistance of bacteria depends significantly on the type of mineral matrix, on which they are immobilized, wherein montmorillonite contributes to an increased survivability in comparison with a silicate matrix. Survivability of the studied bacteria was found to increase with decreasing radiation intensity, despite the impossibility of active reparation processes under experimental conditions. Considering the low intensity of radiation on various space objects in comparison with radiobiological experiments, this suggests a longer preservation of the viable microorganisms outside the Earth than is commonly believed. An increase in bacterial radioresistance was revealed even after one cycle of irradiation of the strains and their subsequent cultivation under favourable conditions. This indicates the possibility of hypothetical microorganisms on Mars increasing their radioresistance.

Signal Improvement for Underwater Measurement of Metal Samples Using Collinear Long-Short Double-Pulse Laser Induced Breakdown Spectroscopy

A collinear long-short double-pulse laser induced breakdown spectroscopy (LS-DP-LIBS) is employed to detect the underwater metal samples. The emission spectra, time-resolved signal, plasma images and sound characteristics of plasma shockwave are experimentally investigated in this work. The results show that the underwater signal of Al, Cu and Fe spectral lines are significantly improved by collinear LS-DP-LIBS with inter-pulse delay of 35 us. The mechanism of the signal improvement is considered to be the pre irradiation effect of long pulse laser beam. In the collinear LS-DP-LIBS method, the long pulse firstly generates a cavitation bubble in water and provides the gaseous environment. Then the short pulse generates the plasma from sample surface. The present experiments show that the collinear LS-DP-LIBS method has acquired significantly signal improvement in underwater measurement of metal samples. This new method has great potential in deep-sea exploration using LIBS.

Microstructure evolution and effect on deuterium retention in oxide dispersion strengthened tungsten during He+ irradiation

Oxide dispersion-strengthened materials W-1wt%Pr2O3 and W-1wt%La2O3 were synthesized by wet chemical method and spark plasma sintering. The field emission scanning electron microscopy (FE-SEM) analysis, XRD and Vickers microhardness measurements were conducted to characterize the samples. The irradiations were carried out with a 5 keV helium ion beam to fluences up to 5.0 × 1021 ions/m2 under 600 °C using the low-energy ion irradiation system. Transmission electron microscopy (TEM) study was performed to investigate the microstructural evolution in W-1wt%Pr2O3 and W-1wt%La2O3. At 1.0 × 1020 He+/m2, the average loops size of the W-1wt%Pr2O3 was 4.3 nm, much lower than W-1wt%La2O3 of 8.5 nm. However, helium bubbles were not observed throughout in both doped W materials. The effects of pre-irradiation with 1.0 × 1021 He+/m2 on trapping of injected deuterium in doped W was studied by thermal desorption spectrometry (TDS) technique using quadrupole mass spectrometer. Compared with the samples without He+ pre-irradiation, deuterium (D) retention of doped W materials increased after He+ irradiation, whose retention was unsaturated at the damage level of 1.0 × 1022D2+/m2. The present results implied that irradiation effect of He+ ions must be taken into account to evaluate the deuterium retention in fusion material applications.

Effect of proton pre-irradiation on corrosion of Zr-0.5Nb model alloys with different Nb distributions

The effect of proton irradiation on corrosion rate of α-annealed and β-quenched Zr-0.5Nb alloys is investigated. The major focuses of this study are to understand i) if the nucleation of irradiation-induced platelets (IIPs)/nanoclusters requires dissolution of Nb-rich native precipitates, ii) if the irradiated native precipitates and interlaths are stable in the oxide, and iii) how much Nb content in the solid solution is suitable to lower the corrosion rate for Zr-Nb alloys. To answer these questions, the major characterization techniques used in this study are APT and (S)TEM/EDS to study the microstructure and microchemistry evolution following irradiation and oxidation.

Incubation Effect of Pre-Irradiation on Bubble Formation and Ablation in Laser Ablation in Liquids.

Pulsed laser ablation in liquids (PLAL) is a multi-scale process, which is widely studied either in batch ablation with prolonged target irradiation as well as mechanistic investigations, in a defined (single-shot) process. However, fundamental studies on defined pulse series are rare. We have investigated the effect of a developing rough morphology of the target surface on the PLAL process with nanosecond pulses and, partially, picosecond pulses. At low fluence the cavitation bubble growth as well as the ablation yield depend on the irradiation history of the target. The bubble size increases with repeated irradiation on one spot for the first 2-30 pulses as well as with the applied dose. This is discussed within the framework of incubation effects. Incubation is found to be important, resulting in a bubble volume increase by a factor of six or more between pristine and corrugated targets. The target surface, changing from smooth to corrugated, induces a more efficient localization of laser energy at the solid-liquid interface. This is accompanied by a suppressed reflectivity and more efficient coupling of energy into the laser-induced plasma. Thus, the cavitation bubble size increases as well as ablation being enhanced. At high fluence, such incubation is masked by the rapid development of surface damage within the first shots, which eventually would lead to a reduction of bubble sizes.

Improved Analysis of Manganese in Steel Samples Using Collinear Long-Short Double Pulse Laser-Induced Breakdown Spectroscopy (LIBS).

A long-short double pulse laser-induced breakdown spectroscopy (long-short DP-LIBS) method was employed to improve the analytical performance of LIBS for the measurement of manganese in steel samples. The long pulse with a duration of 60 μs was generated using a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser which was operated at free-running (FR) mode. To investigate the detection ability without sample preparation, the steel washers were tested using single-pulse LIBS (SP-LIBS) and long-short DP-LIBS, respectively. The measurement results show that long-short DP-LIBS was able to record clear spectra from the steel washers with a surface layer. Through the observation on the laser craters with a scanning electron microscope (SEM), the results suggest that the improvement in detection ability can be attributed to the pre-irradiation effect of long-pulse laser beam. Next, the analytical performance for quantitative measurement of manganese was evaluated employing ten standard steel samples. The results show that the linearity fit (R2) of the calibration curve is 0.988 for long-short DP-LIBS, whereas, R2 is only 0.810 for SP-LIBS under the same measurement conditions. The repeated measurement results show that the average relative standard deviation (RSD) of the tested samples is 29.3% for SP-LIBS and is 10.5% for long-short DP-LIBS. The prediction results also show that the average relative error of prediction (REP) is 94.9% for SP-LIBS and is 4.9% for long-short DP-LIBS.

A study of thermolysis of irradiated diamide-containing extraction systems with nitric acid

Abstract The dynamics of gas release at thermal oxidation of extraction systems on the basis of diamides of dicarbonic acids in fluorinated sulphones with 14 mol/L HNO 3 was investigated. The effect of pre-irradiation of the mixtures with accelerated electrons on the kinetics of their thermolysis was determined. The mixtures were heated in an autoclave at temperatures of 170 and 200 °C and irradiated using an electron accelerator to absorbed doses of 0.1, 0.5, and 1.0 MGy. It has been shown that no conditions for autocatalytic oxidation at thermolysis of extraction mixtures irradiated up to a dose of 1 MGy were developed.

Bubble-loop complexes induced by helium irradiation and effect of pre-irradiation and post-irradiation of hydrogen in reduced-activation ferritic/martensitic steel

ABSTRACTIn the present work, the synergistic effect of high concentration hydrogen and helium on the dislocation loops and bubbles as well as their correlations in reduced-activation ferritic/martensitic (RAFM) steels is investigated. Such an effect was transmuted from 14 MeV neutron irradiation and has been one of the most challenging issues for RAFM steels for future fusion reactors. After low dose (0.18 dpa) high concentration (5000 appm) single-ion helium irradiation at 723 K, very large dislocation loops were observed, and the majority of bubbles were inside dislocation loops, forming bubble-loop complexes. These bubble-loop complexes defects were also present in hydrogen/helium and helium/hydrogen sequential-ion irradiated steels. Pre-irradiated hydrogen ion effectively inhibited the later growth of loops induced by helium post-irradiation, and the higher the ratio of hydrogen to helium fluence, the greater the effect of inhibition. At high fluence of hydrogen pre-irradiation, the structure of bubble-loop complexes disappeared. On the other hand, hydrogen post-irradiation promoted the growth of loops induced by helium pre-irradiation, and the higher the ratio of hydrogen to helium fluence, the greater the effect of promotion. The mechanisms for hydrogen/helium synergistic effects are discussed.

Dynamics of gas release during thermal oxidation of TBP solutions in Isopar-M in two-phase system

ABSTRACTThe dynamics of the gas release at thermal oxidation of the two-phase systems of 30% solution of tri-n-butyl phosphate (TBP) in isoparaffinic diluent Isopar M – aqueous solution of 4.3, 8.2 and 12 mol/L of HNO3 has been investigated within the temperature range from 70°C to 110°C. The effect of pre-irradiation of the system TBP–Isopar-M–HNO3 on the kinetics of its thermolysis has been determined. All of the samples were irradiated with an electron accelerator at a dose rate of 10 kGy/h up to integrated doses of 0.5, 1 and 2 MGy. The parameters of heat and gas emission during thermolysis of the tested extraction system in an open apparatus have been determined experimentally. It has been demonstrated, that there are no conditions for extension of autocatalytic oxidation under heat treatment of two-phase extraction systems in open vessels.

Effect of Gamma-Ray Pre-Irradiation on the Ablation of Polyethylene and Ethylene-Propylene Copolymer Under Continuous CO2 Laser Radiation

We report the effect of preliminary γ-irradiation of polyethylene (PE) and ethylene-propylene copolymer (CEP) on the kinetics of polymer ablation under CO2 laser irradiation. The rate of PE ablation exceeds the rate of CEP ablation at all doses of γ-irradiation. The ablation rate of the polymers can be approximated by a linear function in the initial stage, and the rate reaches a constant value in the second stage of ablation. The rate of laser ablation increases linearly with the dose of preliminary γ-irradiation in both stages of the kinetics. For PE ablation, the duration of the linear increase in rate decreases with increase in preliminary radiolysis dose. The morphology of the crater surface formed during the laser ablation of γ-irradiated polymers is characterized by a more diverse structure.

Effects of sequential helium and hydrogen ion irradiation on the nucleation and evolution of bubbles in tungsten

Irradiations of He+ and H+ have been performed to investigate the effect of H+ irradiation on existing helium bubbles and the effect of pre-irradiation of H+ on the formation of helium bubbles in tungsten. The specimens were irradiated at 800°C with either 10kev-H+, 20kev-He+, or sequentially irradiated with both H+ and He+. After H+ irradiation, the growth of existing helium bubbles was observed. It was also found that pre- or post- irradiation of H+ enhanced the nucleation of helium bubbles. The growth of hydrogen bubbles was also observed after post irradiation of He+. The possible mechanism is discussed.

Study of thermal and radiation stability of the extractant based on CMPO in fluorinated sulfones

ABSTRACTThe two-phase systems of pure diluent FS-13 – aqueous solution of 14 mol/L nitric acid and 0.02 mol/L solution of CMPO in diluent FS-13 – aqueous solution of 14 mol/L HNO3 were studied at autoclave temperatures 170 °C and 200 °C. The effect of pre-irradiation on the kinetics of thermolysis was determined. All samples were irradiated using an electron accelerator at a dose rate of 10 kGy/h up to absorbed doses of 0.1, 0.5 and 1 MGy. The parameters of heat and gas emissions were determined during thermolysis of the studied extraction system in a closed apparatus. It has been shown that the conditions required for the growth of autocatalytic oxidation are not created during heating of the two-phase systems in closed vessels even for the extraction systems contacted with 14 mol/l HNO3 for two weeks.