Gamma Dose Research Articles

Assessment of NORMs (238U, 232Th, 40K) and radiation hazard indices in Beldih apatite mine region of Purulia district, West Bengal, India.

The radiation arising from naturally occurring radioactive materials (NORMs) is the foremost contributor to the collective dose received by the global population. The present study aims to measure the natural background radiation level and the associated gamma radiation dose in air in the Beldih apatite mine region of Purulia district, India. This study is primarily focused on the determination of 238U, 232Th and 40K activities in the sub-surface soil of the study area. The measurements were carried out using a High Purity Germanium (HPGe) detector-based gamma-ray spectrometer with a relative efficiency of 80%. To achieve uniformity in exposure estimations, radium equivalent activity has been calculated. Additionally, the internal hazard index, external hazard index, radioactivity level index and gamma dose rates have been evaluated to estimate the radiation hazard levels in the study area. The comparison of obtained concentrations and hazard indices with global data (UNSCEAR. (2008). Sources, effects and risks of ionizing radiation. United nations scientific committee on the effects of atomic radiation (report to the general assembly, with Annexes).) suggests that this region lies in a relatively high background radiation zone.

Studies on radionuclides in soil samples of of Tiruvannamalai District Tamilnadu, India using Gamma Ray Spectrometry

The activity concentrations of natural radionuclides 226Ra, 232Th, and 40K in soil samples from Tiruvannamalai district, Tamil Nadu, have been estimated using NaI (TI) detector-based gamma spectrometry. The mean activity concentration of 232Th in soil samples is greater and poorer for 226Ra and 40K, respectively, when compared with world average values. Radiation hazard estimation was done by the assessment of radiological parameters such as radium equivalent activity (Raeq), absorbed gamma dose rate (DR), annual effective dose rate (HR), and excess lifetime cancer risk (ELCR). These parameters were compared with international criteria. The findings in the soil showed that there is no major radiological risk to the general public by using these soil samples from the Tiruvannamalai district.

Radon metrology at NARL, Gadanki

It is unavoidable to be exposed to radon and its progeny, and numerous researchers in India have conducted substantial research to understand any potential health implications. It's interesting to observe that the time scale of several atmospheric processes and the half-life of radon, which is 3.82 days, are comparable. As a result, the Radon measurements can be used to understand various research problems in the area of atmospheric physics. The assessment of three years' data of radon activity concentration, as well as its daughter, ambient gamma dose, and climate data, was carried out at the National Atmospheric Research Laboratory, Gadanki, India (13.46° N, 79.17° E). It is possible to observe the breakdown of periodicity, a strong daily and seasonal trend, and the relationship between the measured and dependent variables while looking at a time series in general. Radon activity was shown to exhibit a clearly defined diurnal pattern, and FFT analysis revealed the Radon time series' latent memory of sub-diurnal fluctuations. Radon and its progeny were found to have mean levels of 12.2 ± 2.1 Bq/m3 and 4.2 ± 2.3 mWL, respectively. At NARL, the ambient gamma radiation dose rate was 186 ± 9.3 nSv/hour, which is within UNSCEAR's allowed limits.

The study of dosimetric properties of sulfanilic acid in low radiation dose range using the ESR technique

The development of new dosimeters with good dosimetric properties is important for quality control in radiation applications. In this study, the potential of sulfanilic acid (C6H7NO3S) powder form, as a dosimeter in low-dose ionizing radiation (<30 Gy), was analyzed by an Electron Spin Resonance spectrometer (Bruker EMX-131 X-band). Gamma irradiations were performed at room temperature (290 K) using a 60Co gamma cell supplying a dose rate of 32 Gy/h and X photon irradiations at 6 and 18 MV energies were performed using a variant DHX model clinical linear accelerator (Linac) at a dose rate of 3 Gy/min. While unirradiated (control) sulfanilic acid exhibited no ESR signal, the irradiated sample showed a single-line ESR spectrum spread over a magnetic field range of 100 G, as shown in Figure 2. Variations of the peak heights with the sample mass irradiated at 2 Gy gamma dose were studied in the range of 130–330 mg. The ESR signal intensity observed at g-factor = 2.0053 of this compound is dependent on sample mass, so ∼250 mg was chosen at each step of the study. The paramagnetic center formed in the gamma-irradiated sulfanilic acid was followed over 50 days. The dose-response curves were given in the dose range from 0.05 to 10 Gy for the sample exposed to gamma radiation and for the sample exposed in the range of 0.05 Gy–30 Gy at 6 and 18 MV X-ray energies. The fitting values of the function that best describes dose-response curves are calculated. In the g value region, where the ESR signal was observed in the irradiated sample, the lowest dose value at which the signal could be read was 50 mGy, significantly different from the noise. With all these investigations, sulfanilic acid can be used to estimate gamma radiation dose within boundary conditions in medical applications.

Investigation of some optical, conducting and radiation shielding properties of Dy3+ ions doped boro-silicate glass systems

Three borosilicate glass samples of 25 % Si2O – 30 % Na2O – 45 % B2O3 doped with x Dy2O3 (where x = 0, 2, and 4 mol %) were prepared using the melt quenching technique. Photoluminescence spectra for glass samples were studied when excited by 350 nm in the 400–800 nm range, where emission sharply increases for samples doped with 2 % Dy2O3 (BSNDy2) at 580 nm after exposed to 30 kGy. Also, glass containing 2 % Dy photoluminescence constants, such as decay curves CIE chromaticity, was measured for all samples that gave three decay behaviors: slow, intermediate, and fast. Experimental lifetime (τexp.), color coordination (X, Y), and yellow/blue intensity ratio (y/b) beside the color correlated temperature (CCT) were determined before and after being irradiated by 30 and 60 kGy from γ ray source where the y/b ratio of BSNDy2 increase by increasing exposure to gamma doses and were >1. In addition, electrical conductivity at different temperatures was investigated as the BSNDy2 sample gave the highest conductivity and decreased by BSNDy4. Moreover, shielding parameters such as the tenth value layer, half value layer, mean free path and mass attenuation coefficient values were calculated at different gamma-ray energies via the Phy-X program, showing the highest values for MAC, Zeff, Neff, and Ceff for BSNDy4 sample. The findings showed that adding Dy2O3 to the glass gave a fortified shielding character.

Investigation of natural radioactivity in soil of selected hospitals in Imo State, Nigeria

We measured the terrestrial activity contents, radiation doses; hazard indices and excessive lifetime cancer risk (ELCR) from primordial radionuclides (226Ra, 232Th and 40K) in 50 soil samples collected from the five selected hospitals within Imo State, Nigeria. Radioactivity measurements were carried out by the method of gamma-ray spectrometry with thallium doped sodium iodide [NaI(Tl)] detector. The mean activity values obtained for the radionuclides 226Ra, 232Th and 40K (respectively) in Federal Medical Centre, Owerri (FMC); General Hospital, Umuguma, Owerri West, (GHW); Neuroscience Hospital, Ohaji Egbema (NHO); St. Joseph Hospital, Okigwe (SJH); Imo State University Teaching Hospital, Orlu (IMSUTH) are: 20.56±4.73, 14.96±3.42 and 105.65±31.40 Bqkg-1; 11.77±3.03, 17.45±4.20 and 63.67±18.44 Bqkg-1; 17.97±4.65,10.02±2.18 and 190.43±42.83 Bqkg-1; 11.36±3.71, 17.39±4.46 and 76.29±25.08 Bqkg-1; and 11.84±3.64, 4.89±2.25 and 165.18±58.41 Bqkg-1 respectively. These values were below the worldwide average values: 32 Bqkg-1 for 226Ra, 45 Bqkg-1 for 232Th, and 412 Bqkg-1 for 40K as documented by UNSCEAR (2000). 40K recorded the highest mean activity compared to 226Ra and 232Th in the studied soil samples. Radium equivalent activity (Raeq), absorbed gamma dose rate (Dr), annual effective dose equivalent (AEDE), external hazard index (Hex), gamma representative index (Ιϒr) and annual gonadal dose equivalent (AGDE), were calculated to quantify the radiation risk to the public from exposure to 226Ra, 232Th and 40K in the studied samples. In addition, excess lifetime cancer risk (ELCR) was also accessed. The mean computed values of the excess lifetime cancer risk for FMC, GHW, NHO, SJH and IMSUTH are 0.08±0.03, 0.09±0.15, 0.10±0.2, 0.10±0.03 and 0.07±0.02 respectively. The mean values of these hazard parameters were within the acceptable safety limits provided for human safety and environmental protection.

Assessment of radioactivity in sand samples from eastern Nepal in perspective of radiological hazards.

This study was conducted to investigate the activity concentrations of 226Ra, 232Th and 40K in the sand samples and the health hazards associated with them utilizing a NaI (Tl) gamma spectrometer. The average activity concentrations of 226Ra, 232Th and 40K were found to be 24.8±10.1, 39.8±16.4 and 531.3±52.8Bq kg-1, respectively. The calculated radiological hazard parameters, including radium equivalent activity, absorbed gamma dose and effective dose rate, were found to be 122.7±34.0Bq kg-1, 57.7±14.9 nGy h-1 and 0.3±0.1mSv y-1, respectively. Notably, these results were observed to be below the recommended thresholds. Other measured hazard indices were also lower than the prescribed values. From a radiological perspective, the present study concludes that the sand samples do not pose any threat to human health when utilized as a building material.

Negligible radiological impact of Indian nuclear power plants on the environment and the public: Findings from a 20-year study

Nuclear power plants, recognized for their extended operational life, minimal greenhouse gas emissions, and high-power density, are deemed as reliable energy sources. Nonetheless, concerns persist regarding the radioactive discharges from these plants and their potential impact on health and the environment. To comprehend the radiological implications of such releases, this study presents, for the first time, an analysis of radiological data from 7 Indian nuclear power plants (NPPs), collected by Indian environmental survey laboratories (ESL) over the past two decades (2000-2020). This dataset encompasses radioactivity concentrations in the atmospheric, aquatic, and terrestrial environments within a 30 km radius of each NPP, as well as the annual cumulative external gamma doses recorded by environmental thermoluminescence dosimeters (TLDs). The analysis yielded several key findings: (i) Radioactivity concentrations around the NPPs were low and comparable to values measured at other nuclear power plant sites worldwide; (ii) Tritium concentrations in receiving water bodies were <1 % of the internationally recommended limit of 10,000 Bq/l; (iii) The estimated total radiation doses to the public were at most 10 % of the stipulated regulatory dose limit of 1000 μSv and consistently decreased over the study period and (iv) Variations in doses among the NPP sites were primarily attributed to legacy technology used in specific reactors. These results indicate efficient and secure reactor operations and the minimal contribution of Indian nuclear power plants to anthropogenic doses in the country. The findings hold potential significance for reinforcing India's commitment to advancing its nuclear power program.

Mechanical and electrical performance of glass fiber reinforced plastic insulation for cryogenic application in fusion magnet irradiated in fast breeder reactor

In a superconducting (SC) magnet fusion reactor, the insulation material used has to withstand significant fluxes of neutrons and neutron-induced gamma radiation. Epoxy-based glass fiber-reinforced plastic (GFRP) composites are the insulation system for fusion magnets and are highly demanding. This insulation system requires excellent mechanical and electrical performance under mixed neutron and gamma radiation at cryogenic temperatures. The insulation material developed consists of boron-free S-glass fiber impregnated with a two-component modified Diglycidyl ether of Bisphenol-A (DGEBA) epoxy resin. An anhydride-cured DGEBA resin system is not suitable for cryogenic temperatures. Therefore, to overcome this thermal stress issue in cryogenic components of SC magnets, a high-toughness, flexible, aromatic amine-cured epoxy resin system was developed for the insulation system. In order to assess the radiation resistance for mechanical and electrical properties, the composite samples were irradiated in the fast breeder test reactor (FBTR) at IGCAR, Kalpakkam, India. The irradiation experiment was carried out for a neutron fluence of 1.0E+21 n/m2 and a gamma dose of 0.4 MGy at a full reactor power of 32 MWt. The tensile strength, interlaminar shear strength, and breakdown strength measurements were investigated before and after irradiation at room temperature and 77 K. The test results indicate that no significant degradation was observed in the properties of the irradiated samples up to the above-mentioned radiation doses.

Spectroscopic and electrical changes in Lr-115 type II nuclear track detector before and after gamma radiation

In this research, the changes in the structural, spectroscopic, and electrical properties of the Lr-115 type II nuclear track detector were investigated before and after gamma irradiation. The FT-IR, X-ray, and UV–Visible spectra were recorded and studied in detail before and after irradiation process. We have arrived at the following results, the X-ray diffraction reveals that irradiated Lr-115 diffraction displays an increase in peak intensity and width at half maximum which is commonly associated with polymer crystallinity. After irradiation, the IR bands at 1447 cm−1 assigned to O-NO2 rapidly decreased, and the band at 802 cm−1 due to C–O–C shifted to 784 cm−1. From UV–Visible measurements, as irradiated doses increase, the surface plasmon absorption in irradiated samples causes the extinction coefficient (k) of the sample peak at = 199 nm to increase with increasing wavelength up to 221 nm. With increasing gamma dose, the obtained data revealed a decrease in the optical energy gap (Eg) and increases of the number of carbon atoms in a formed cluster. Increasing of the gamma doses caused an increase in the AC electrical conductivity. Furthermore, the dielectric constant was studied at room temperature as a function of the dose variation. The results indicate that gamma-ray irradiations improve the optical and electrical properties of Lr-115.

Godiva-IV dosimetry exercise 2022 preliminary results

Integral Experiment Request (IER) 538 is part of a series of dose characterization and nuclear accident dosimetry (NAD) exercises performed under the Department of Energy (DOE) Nuclear Criticality Safety Program (NCSP). This is the second NAD exercise using the Godiva-IV critical assembly and the third NAD exercise overall. The participating laboratories provided their own dosimeters that were mounted on the Lawrence Livermore National Laboratory (LLNL) BOttle Manikin ABsorption (BOMAB) phantoms and aluminum plates. The BOMABs and plates were placed at two, three, and four meters away from the center of Godiva. Alongside the NADs, there was a LLNL Passive Neutron Spectrometer (PNS), Atomic Weapons Establishment (AWE) PNS, and Y-12 Sphere present to measure the neutron dose from Godiva-IV. Two irradiations were conducted to test the NAD performance from each laboratory and assesses their performance to the DOE-STD-1098-2017 part 515 criteria. Neutron and gamma doses were measured prior to this exercise. This work presents a model for the neutron and gamma dose respectively to serve as the reference value. A code written in C/C++/ROOT was used to fit the measured neutron and gamma dose with the new models. It was assumed that the neutron and gamma doses are proportional to the change in temperature of Godiva after a burst irradiation. Uncertainties for the reference values were calculated using error propagation of the model’s parameters. Preliminary results (within twenty-four hours) and final results were compared for each laboratory. On average of all the participating laboratories, 32% of neutron doses and 78% of gamma doses were outside the DOE standards. One laboratory did not report their dose readings and were not included in this average. There is a bias for a lower neutron dose and a higher gamma dose based on the distribution of results. In comparison with the past Godiva-IV NAD exercise, there is an improvement in neutron dose readings by 20%.

Perovskite-based detector for reactor dosimetry monitoring

Hybrid halide perovskites have demonstrated significant efficiency in detecting a broad spectrum of high-energy radiation, including X-rays, gamma rays (γ-rays), and neutrons. Given the common occurrence of mixed radiation fields, we investigated the performance of a perovskite-based detector in a neutron-gamma mixed field. A large methylammonium lead tribromide (MAPbBr3) single crystal (SC) was synthesized via the oriented crystal-crystal intergrowth method. This SC was used to fabricate a gamma detector with carbon electrodes, which was tested in the CROCUS zero-power reactor cavity. The detector’s photocurrent response exhibited a strong correlation with known gamma dose rates, as measured by an ambient Berthold LB 112 gamma probe, facilitating the accurate conversion of photocurrent to dose rate. Notably, the device did not exhibit degradation under neutron radiation exposure. To further assess the impact of neutrons, X-ray diffraction and electron paramagnetic resonance analyses were performed on small MAPbBr3 SCs grown by inverse temperature crystallization. These SCs were irradiated within the CROCUS reactor core and by a Pu-Be neutron source at liquid nitrogen temperature. Our findings indicate that the perovskite material can withstand the nominal in-core operation conditions of the CROCUS reactor. Additionally, it endures irradiation at liquid nitrogen temperature, corresponding to a fast neutron fluence of approximately 1010 cm-2 and a gamma radiation dose of about 50 Gy, confirming only the temporary creation of defects. No signs of long-term deterioration were observed, suggesting a potential self-healing mechanism. This resilience positions perovskite SCs as viable candidates for in-core radiation detection, supporting the further development of miniaturized MAPbBr3 SC devices for such applications.

Радиационная обстановка в районе горного массива Бештау

The article presents the outcomes of the dead uranium mine inspection and its impact on the current radiation situation in the Beshtau area, as well as radiation doses to the people using the area as a recreation land. The Beshtau mounting uranium mine was in use from 1940s to 1990s. Several stages of the site remediation were conducted since the 1990s. For these purposes gamma dose rates, density of radon flux from ground surface and its products concentration in the atmospheric air, the content of natural radionuclides in the ground and groundwater were estimated. According to the measurements data it is seen that the area around the main mine facilities located in the southwestern and southern parts of the Beshtau mounting, is the mostly susceptible to radioactive contamination. The water from the springs in this area is not suitable for drinking because the levels of uranium and radon in the water exceed the control safe limits. According to radiation dose estimates in the considered area, it becomes evident that the radiation risk in the area depends mainly on the presence of the gas flows from the tunnel, radiation risk can be higher if the gas flow is not fully extinguished. The tunnels mouths in the study area are not completely extinguished, and the mine air is periodically blown out of them. Due to the current situation, the levels of radon and gamma radiation around the adit mouths exceed the permitted safe limits. If people stay in this area for 4 hours, they can receive radiation dose above 1.0 millisievert (mSv), that exceeds the recommended safe limit. In this regard, it would be advisable to implement measures to prevent or reduce the time people spend in the areas where the former tunnels mouths are located.

Assessment of Natural Background Radiation Exposure in the Federal Capital Territory of Nigeria

The detrimental effects of environmental contamination and deterioration on health are a worldwide concern and Nigerian environmental and public authorities continue to be concerned about the risk to public health. The water, the sky, construction materials and the earth's crust all release natural background radiation that contaminates the environment around us. Additionally, people are exposed to background radiation that comes from internal, cosmic, and terrestrial sources, although, the altitude determines the amount of cosmic radiation exposure, and high altitudes result in large radiation doses. Monitoring the amounts of radiation to which humans are exposed, either directly or indirectly, requires an understanding of the natural background radiation in the environment. The current study attempted to create a baseline of outdoor background radiation in FCT for exposure rate, absorbed dose rate, annual effective dose equivalent, and excess life cancer risk. The study used a very sensitive survey meter to measure the BIR. The average BIR value found in the research areas is marginally below the 0.013mRh-1 global BIR level, indicating an almost high BIR level for the FCT while the absorbed dose rates of 105.85nGy/hr was greater than the 59nGy/hr global population weighted average gamma dose rates estimate. The obtained annual effective dosage equivalent value is greater than the global average normal annual effective dosage level for outdoor environments, and the excess lifetime cancer risk values were higher than the 0.29×10-3 allowable level as reported by UNSCEAR &amp; ICRP. Therefore, the general people and those who live in environmentally sensitive areas may experience immediate health effects from contamination and radiation levels at the current rates.

Hazard assessment of outdoor gamma radiation in Tavsanli, Kutahya region of Turkiye

In the present study, outdoor gamma dose rates have been measured by using a NaI(Tl) scintillation detector in 20 measurement points in the Tavsanly district center of Kutahya province in Turkiye. Annual effective dose equivalents and lifetime cancer risks have been calculated from the obtained results as (106.64 ?6.20) ?Sv and (3.73 ?0.2) ?10-4, respectively. The results have been compared with those of other studies for Turkiye and the world literature

Overview of the new capabilities in the Monte-Carlo particle-transport code NECP-MCX V2.0

NECP-MCX is a Monte-Carlo particle-transport code developed by the Nuclear Engineering Computational Physics (NECP) Lab. of Xi’an Jiaotong University in 2018. The first version of NECP-MCX is focused on addressing the challenge of deep-penetration radiation-shielding problems. In recent years, new capabilities of unstructured-mesh geometries, dose engine for Boron Neutron Capture Therapy (BNCT), neutron noise analysis, sensitivity analysis, depletion and activation calculation, simulation of randomly dispersed media, homogenization and gamma dose calculation based on point-kernel integral method are implemented in NECP-MCX V2.0. A user interface of NECP-MCX V2.0 is also under active development. This paper will introduce these new capabilities.

Estimation of Radiation Dose in Building Materials Used In Federal University Gusau Using Gamma-Ray Spectroscopy Analysis

This study estimated the radiation dose in building materials (sand, cement, and granite) in Federal University Gusau, Zamfara State, Nigeria, through gamma-ray spectrometry system using a Sodium Iodide Thallium activated "NaITl" detector in a low background configuration. The range of the average activity concentration of 226Ra was found to be 56.65±0.75Bqkg-1 to 159.45±2.68Bqkg-1, which was higher than that of the world mean value for soil 35Bqkg-1,for 232Th the range was 46.65±0.45Bqkg-1 to 79.32±1.68Bqkg-1, all the samples, were found to be higher than that of the world mean for soil 30Bqkg-1. While the activity concentrations of 232Th levels of blocks, granite, and sand samples are all above the world range, except the cement which was within the worldwide range 194.84±1.31Bqkg-1 to 656.84±0.76Bqkg-1. The average activity concentration of 40K for cement, sand, and blocks was within the worldwide range, with granite samples slightly higher than the world mean value for soil 400Bqkg-1. The results have been compared with the world mean values of 35, 30, and 400Bqkg-1 specified by the UNSCEAR (2016). Concerning radiological risk to human health, the absorbed gamma dose rate (D) was estimated to be above the world average range of 55nGyh-1; the outdoor annual effective dose equivalent (AEDE) were, estimated to be below the permissible limit of 0.07mSvy-1. The values of Raeq, Hex, and Hin for all the samples in the present work are lower than the accepted safety limit value of 370Bqkg-1 and below the limit of unity, respectively.

Assessment of natural radioactivity in soil and olive mill pomace utilizing nal (TI) gamma-ray spectrometry and low background alpha/beta counting system

The study conducted in the northwest region of Jordan aimed to assess the levels of natural radioactivity in soil and olive mill pomace (OMP) samples. The researchers used Nal (TI) gamma-ray spectrometry to measure the activity concentrations of 226Ra, 232Th, 40K, and 137Cs in the samples. The average activity concentrations of 226Ra, 232Th, 40K, and 137Cs in the soil samples were found to be 18.624 ± 5.82, 12.276 ± 5.728, 518.33 ± 212.57, and 0.140 ± 0.09 (Bq,kg−1), respectively. In the OMP samples, the average activity concentrations of 226Ra, 232Th, and 40K were 7.272 ± 4.386, 3.454 ± 1.503, and 169.997 ± 81.873 (Bqkg−1), respectively, and no 137Cs was detected.The study also investigated fundamental parameters associated with radon, specifically the radon emanation coefficient (RnEC) and radon mass exhalation rate (Ex). The RnEC values ranged from 0.621 to 0.78 (Bqkg−1), with an average value of 0.71 ± 0.06 (Bqkg−1). The estimated Ex from the soil samples ranged from 65.83 to 124.86 (mBqkg−1h−1), with an average value of 99.74 ± 21.73 (mBqkg−1h−1).Regarding radiological hazards, the study examined various parameters, including radium equivalent activity, external and internal hazard indices, gamma and alpha indices, absorbed gamma dose rate, and excess lifetime cancer risk. All of these assessed values were found to be below the worldwide recommended limits for radiological safety.Additionally, the study analyzed the concentrations of gross alpha and gross beta radioactivities in soil and OMP samples. The soil samples had an average gross alpha activity of 4.642 ± 1.04 (Bqkg−1) and an average gross beta activity of 48.13 ± 14.50 (Bqkg−1). The OMP samples showed an average gross alpha activity of 0.32 ± 0.27 (Bqkg−1) and an average gross beta activity of 59.19 ± 12.94 (Bqkg−1).Overall, the obtained results are crucial for evaluating the radiological risks associated with natural radioactivity in the northwest region of Jordan. The findings establish baseline data for comparison and reference for radioactivity levels in the environment.

Gamma Irradiation Promotes the Growth Rate of Thai Pigmented Rice As Well As Inducing the Accumulation of Bioactive Compounds and Carbohydrate Hydrolyzing Enzymes Inhibitors (α-Glucosidase and α-Amylase) under Salt Conditions.

Rice contains many bioactive compounds that perform various biological activities. Some of these compounds have been identified as α-glucosidase and α-amylase inhibitors, including guaiacol, vanillin, methyl vanillate, vanillic acid, syringic acid, and 2-pentyl furan. In this study, we assessed the growth rate, photosynthetic pigment content, phenolic content, and flavonoid content of gamma-irradiated Thai pigmented rice. Bioactive components of gamma-irradiated rice that had been subjected to salt treatment were also investigated. The findings showed that production of photosynthetic pigments, which are associated with plant growth, was induced by low gamma exposure. Phenolic and flavonoid content of rice was increased after gamma irradiation at 5 to 1,000 Gy. Both gamma irradiation and the salt conditions changed the quantity of vanillin, methyl vanillate, and vanillic acid in the rice. However, at a salt concentration of 40 mM, the salt stress had more of an effect than the gamma dosage. However, the high concentrations of methyl vanillate and vanillic acid detected in the rice under salt conditions were ameliorated by gamma irradiation. Guaiacol served as the substrate of guaiacol peroxidase for catalyzed reactive oxygen species, as evidenced by the observation that the guaiacol content of rice decreased between increased gamma dosages. A gamma dose of 40 to 1,000 Gy resulted in the production of syringic acid. Under salt stress, syringic acid buildup was also seen to be ameliorated by gamma irradiation. In comparison to salt conditions, particularly for 20 mM salt, gamma irradiation had less of an impact on the 2-pentyl furan in rice.

Source term inversion of short-lived nuclides in complex nuclear accidents based on machine learning using off-site gamma dose rate

During nuclear accidents, large amounts of short-lived radionuclides are released into the environment, causing acute health hazards to local populations. Therefore, it is particularly important to obtain source-term information to assist nuclear emergency decision makers in determining emergency protective measures. However, it is extremely difficult to obtain reliable contaminant monitoring instrument readings to estimate the source term based on core conditions, release routes, and release conditions. Currently, a wide variety of source-term inversion methods are attracting increasing attention. In this study, the release rates of four typical short-lived nuclides (Kr-88, Sr-91, Te-132, I-131) in two complex nuclear accident scenarios were estimated using a machine-learning method. The results show that the best estimation performance is obtained with the long short-term memory network, and the mean absolute percentage errors for the release rates of the four nuclides at 10 h under the two nuclear accidents are 9.87% and 11.08%, 17.49% and 16.51%, 7.16% and 8.35%, and 38.83% and 41.87%, respectively. Meanwhile, the mean absolute percentage errors for Te-132 (7.16% and 8.35%) were the lowest among all the estimated nuclides. In addition, stability analysis showed that the gamma dose rate was the key parameter affecting the estimation accuracy.