• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3816-3823
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• 2022

This work analyzed the dosimetric difference between the intensity modulated radiotherapy (IMRT), partial/single/double-arc volumetric modulated arc therapy (PA/SA/DA-VMAT) techniques in treatment planning for treating more than one target of lung cancer at different isocenters. IMRT and VMAT plans at different isocenters were created systematically using a Harold heterogeneous lung phantom. The conformity index (CI), homogeneity index (HI), gradient index (GI), dose-volume histogram and mean and maximum dose of the PTV were calculated and analyzed. Furthermore, the dose-volume histogram and mean and maximum doses of the OARs such as right lung, contralateral lung and non GTV were determined from the plans. The IMRT plans showed the superior target dose coverage, higher mean and maximum values than other VMAT techniques. PA-VMAT technique shows more lung sparing and DA-VMAT increases the V_5/10/20 values of contralateral lung than other VMAT and IMRT techniques. The IMRT technique achieves highly conformal dose distribution to the target than other VMAT techniques. Comparing to the IMRT plans, the higher V_5/10/20 and mean lung dose were observed in the contralateral lung in the DA-VMAT.

• Nuclear Engineering and Technology
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• v.53 no.4
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• pp.1323-1330
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• 2021

This work reported the radiation shielding characteristic of the bismuth titanium vanadium sodium tellurite glass system. The density of the specially-developed glass samples was increased from 2.21 to 4.01 g/cm³ with the addition of Bi₂O₃, despite the fact the molar volume is decease within 85.43-54.79 cm³/mol. The WinXcom program was used to approximate the effect of Bi₂O₃ on the gamma radiation shielding parameters of bismuth titanium vanadium sodium tellurite glasses. The ㎛ values decrease with the increase of Bi₂O₃ concentration. The computed data shows that the glass sample with 20 mol.% of Bi₂O₃ content has the greatest radiation attenuation performance in comparison to other selected glasses. The Bi₂O₃-TiO₂-V₂O₅-Na₂O-TeO₂ glass system shows excellent neutron shielding material with high long-term light transmittance and discharge resistance and could be potentially used as transparent radiation-resistant shielding glass applications.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.1071-1084
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• 2022

The present study aims to investigate the dynamic properties of a novel isolation system composed of separate rubber and wire isolators. The testing program comprised pure compressive, pure-shear, compressive-stress dependence, and shear-strain dependence tests that used full-scale test specimens according to ISO 22762-1. A total of 22 test specimens were fabricated and investigated. Among the tests, the pure compressive test was a destructive test that reached up to the failure stage, whereas the others were nondestructive tests before the failure stage. Similar to the pure-shear test, at each compressive-stress level in the compressive dependence test or at each shear-strain level in the shear-strain dependence test, the cyclic loading was conducted for three cycles. In the nondestructive tests, examination of the dynamic shear properties in the X-direction was independent of the Y-direction. The test results revealed that the increase in the shear strain increased the energy dissipation but decreased the damping ratio, whereas the increase in the compressive stress increased the damping ratio. In addition, a macro model was developed to simulate the load-displacement response of the isolation systems, and the prediction results were consistent with the experimental results.

• Journal of radiological science and technology
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• v.46 no.1
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• pp.37-42
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• 2023

Most of research on environmental radioactivity is conducted in areas near nuclear power plants, so basic data about the distribution of environmental radioactivity in soil in other areas are insufficient. Therefore, in this study, divide into four categories by the land development characteristics of Incheon and the purpose of development, and confirm the stability of the Incheon through soil sample collection and gamma-ray analysis based on ⁴⁰K, ¹³⁷Cs and ²²⁶Ra (²¹⁴Pb, ²¹⁴Bi). The spectrum obtained by measuring for 80,000 seconds by using the HPGe detector was analyzed by Genie 2000 program. Soil radioactivity concentrations in urban parks of Incheon area are generally within a safe range compared to the results of the Nuclear safety and security commission. However, as ¹³⁷Cs was detected in one park, which will require continuous monitoring.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1031-1035
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• 2023

Neutron is an indirectly ionizing particle without charge, which is normally measured by detecting reaction products. Neutron detection system based on measuring gadolinium-converted gamma-rays is a good way to monitor the neutron because the representative prompt gamma-rays of gadolinium have low energies (79, 89, 182, and 199 keV). Low energy gamma-rays and their high attenuation coefficient on materials allow the simple design of a detector easier to manufacture. Thus, we designed a cadmium zinc telluride detector to investigate feasibility of simultaneous detection of gamma-rays and neutrons by using the Monte-Carlo simulation, which was divided into two parts; first was gamma-detection part and second was gamma- and neutron-simultaneous detection part. Consequently, we confirmed that simultaneous detection of gamma-rays and neutrons could be feasible and valid, although further research is needed for adoption on real detection.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2166-2171
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• 2023

In the present study, six silicone rubber doped by tellurium borate oxides were fabricated using the casting method. The densities of the fabricated silicon rubber-doped by tellurium borate oxides samples were measured using the Archimedes Method. Moreover, the linear attenuation coefficient of silicone rubber doped tellurium borate oxides samples was evaluated experimentally using the hyper pure germanium, and the recorded linear attenuation coefficient values were affirmed using the theoretical Phy-X program. The experimental measurements were performed using the narrow beam transmission method with radioactive isotopes Am-241, Cs-137, and Co-60 with energies of 59, 661, 1173, and 1332 keV. The linear attenuation coefficient values showed an enhancement by 4.73 times, 1.20 time, 1.17, time, and 1.17 time, respectively at gamma photon energies of 59, 661, 1173, and 1332 keV, when the TeO₂ concentration increased in the fabricated composites from 0 to 50 wt%. The enhancement of the linear attenuation coefficient values has a positive effect on the transmission rate values where the half-value thickness and transmission rate were decreased accompanied by an increase in the RPE.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.762-769
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• 2024

The TMSR-SF0 simulator is an integral effect thermal-hydraulic experimental system for the development of thorium molten salt reactor (TMSR) program in China. The simulator has two heat transport loops with liquid FLiNaK. In literature, the 95% level confidence uncertainties of the thermophysical properties of FLiNaK are recommended, and the uncertainties of density, heat capacity, thermal conductivity and viscosity are ±2%, ±10, ±10% and ±10% respectively. In order to investigate the effects of thermophysical properties uncertainties on the molten salt heat transport system, the uncertainty and sensitivity analysis of the heat transfer characteristics of the simulator system are carried out on a RELAP5 model. The uncertainties of thermophysical properties are incorporated in simulation model and the Monte Carlo sampling method is used to propagate the input uncertainties through the model. The simulation results indicate that the uncertainty propagated to core outlet temperature is about ±10 ℃ with a confidence level of 95% in a steady-state operation condition. The result should be noted in the design, operation and code validation of molten salt reactor. In addition, more experimental data is necessary for quantifying the uncertainty of thermophysical properties of molten salts.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1145-1152
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• 2024

To realize an initial objective of the negative ion-based neutral beam injection (N-NBI) at the Comprehensive Research Facility for Fusion Technology (CRAFT) test facility, which targets an H⁰ beam power of 2 MW at an energy of 200-400 keV and a pulse duration of 100 s, it is crucial to study the cesium dynamics of the negative ion source. Here a numerical simulation program CSFC3D is developed and applied to simulate the distribution and time dynamics of cesium during short pulses. The calculations show that most of the cesium on the plasma grid (PG) area originates from the release of cesium that is accumulated within the ion source in the plasma phase. Increasing the wall temperature reduces the loss of cesium on the wall of the ion source. Furthermore, the thickness of the cesium monolayer is directly influenced by the PG temperature. Both simulated and experimental results demonstrate that maintaining the PG temperature between 180 ℃ and 200 ℃ is essential for enhancing the performance of the ion source and optimizing the cesium behavior.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.333-344
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• 2023

To validate the numerical model used in the study of deep disposal of spent nuclear fuel, we selected benchmark cases and performed numerical model validation. We selected the DECOVALEX-THMC Task D_THM1 FEBEX Type benchmark case, which was conducted from 2003 to 2007. We analyzed the thermal-hydraulic (TH) behavior using the finite element program CODE_BRIGHT and verified the results against previous studies. The temperature results were similar to the results of DECOVALEX-THMC Task D. The saturation results showed a similar trend to the results of DECOVALEX-THMC Task D, but the time to reach full saturation was different.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2698-2703
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• 2024

A bilateral comparison was conducted between the International Atomic Energy Agency (IAEA) and the Korea Research Institute of Standards and Science (KRISS) to measure the absorbed dose to water in accelerator photon beams. KRISS served as a linking laboratory to compare the IAEA standard with the key comparison reference value (KCRV) of the BIPM.RI(I)-K6 program, in which KRISS participated in 2017. Two ionization chambers from the IAEA were used as transfer instruments for the comparison. Both laboratories measured the calibration coefficients of these instruments and calculated the ratios. The ratio of the KRISS standard to the KCRV was applied to obtain the degree of equivalence of the IAEA, along with its uncertainty. The largest deviation of the IAEA measurement from the KCRV was 3.4 mGy/Gy, significantly smaller than the expanded uncertainty of 10.7 mGy/Gy (k = 2, 95% level of confidence). This study demonstrates the equivalence of IAEA's measurement standard for accelerator photon beams to other primary standard dosimetry laboratories. It provides evidence for the satisfactory operation of IAEA's quality management system and enhances the international credibility of the IAEA SSDL network, particularly in high-energy accelerator photon beams from linear accelerators.