• Nuclear Engineering and Technology
• /
• v.53 no.5
• /
• pp.1479-1482
• /
• 2021

Research reactors are typically well-suited for outreach activities at different levels. However, unplanned seeking to increase the utilization of a research reactor may result in weakening the nuclear security of this facility. Research reactor staff might be in shortage of a functional nuclear security culture; specifically, there might be a conviction that the necessities of research can be given the priority over consistence with security procedural requirements. Research reactors are usually parts of bigger institutes or research labs of different activities. Moreover, the employments of research reactors are usually with the purpose that easy entry to the reactor premises is fundamental. So, they could be co-situated in places with different sorts of activities, mostly under similar security arrangements. The co-area of research reactor offices among different kinds of research labs introduces explicit security issues, the effects of which should be viewed as when building up a nuclear security framework. Notwithstanding potential security vulnerabilities presented in the design, research reactors frequently have devices kept promptly accessible to encourage research and education. The accessibility of these sorts of hardware could be used by an authorized person to commit an unapproved activity or cause harm. This paper aims to present insights to compromise contradicting conditions in new research reactors in which both enhancing utilization and ensuring security are satisfied.

• Nuclear Engineering and Technology
• /
• v.55 no.5
• /
• pp.1708-1717
• /
• 2023

The grade analysis of lead-zinc ore is the basis for the optimal development and utilization of deposits. In this study, a method combining Prompt Gamma Neutron Activation Analysis (PGNAA) technology and machine learning is proposed for lead-zinc mine borehole logging, which can identify lead-zinc ores of different grades and gangue in the formation, providing real-time grade information qualitatively and semi-quantitatively. Firstly, Monte Carlo simulation is used to obtain a gamma-ray spectrum data set for training and testing machine learning classification algorithms. These spectra are broadened, normalized and separated into inelastic scattering and capture spectra, and then used to fit different classifier models. When the comprehensive grade boundary of high- and low-grade ores is set to 5%, the evaluation metrics calculated by the 5-fold cross-validation show that the SVM (Support Vector Machine), KNN (K-Nearest Neighbor), GNB (Gaussian Naive Bayes) and RF (Random Forest) models can effectively distinguish lead-zinc ore from gangue. At the same time, the GNB model has achieved the optimal accuracy of 91.45% when identifying high- and low-grade ores, and the F₁ score for both types of ores is greater than 0.9.

• Journal of Radiation Protection and Research
• /
• v.37 no.4
• /
• pp.177-180
• /
• 2012

Industrial radiography practice is usually employed in public domain. Over the years there are several radiation accidents reported in this practice. The accidents often result in severe or fatal exposures to occupational workers and public. The number of radiation accidents is also significant when compared with other industrial accidents. This paper describes practice specific training as one of the measures to the improve radiation safety and reduce the accidents. The efforts by International Atomic Energy Agency (IAEA) to disseminate information and to improve the radiation safety status in industrial radiography are also discussed.

• Journal of the Korean Magnetic Resonance Society
• /
• v.19 no.3
• /
• pp.119-123
• /
• 2015

The thermodynamic properties and structural geometry of $KMgCl_3{\cdot}6H_2O$ were investigated using thermogravimetric analysis, differential scanning calorimetry, and nuclear magnetic resonance. The initial mass loss occurs around 351 K ($=T_d$), which is interpreted as the onset of partial thermal decomposition. Phase transition temperatures were found at 435 K ($=T_{C1}$) and 481 K ($=T_{C2}$). The temperature dependences of the spin-lattice relaxation time $T_1$ for the $^1H$ nucleus changes abruptly near $T_{C1}$. These changes are associated with changes in the geometry of the arrangement of octahedral water molecules.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.1
• /
• pp.177-180
• /
• 2010

• Nuclear Engineering and Technology
• /
• v.54 no.4
• /
• pp.1295-1300
• /
• 2022

There has been increased interest in researching risk perception of radiation to implement successful risk communication, particularly given the recent worldwide nuclear policy movement regarding nuclear energy. This study aimed to investigate characteristics of risk perception among residents living near normally operating nuclear power plants in South Korea by identifying factors associated with risk perception. A survey was conducted with face-to-face interviews for 1200 residents aged 20e84 years by gender- and age-stratified random sampling. Risk perception was associated with trust perception in nuclear safety, but was not highly correlated with benefit perception for utilizing nuclear power. Relatively high risk perception was observed in women, older age groups, and residents not having experience of nuclear-related education or work. This association remained after adjusting for other factors including benefit perception, trust perception, and psychological distress. In addition to these individual characteristics, risk perception was also associated with a residential district's own unique context, indicating that a strategy of risk communication should be developed differently for residents facing nuclear-related circumstances. Given that risk perception can be changed, depending on social values such as safety culture and economic setting, further studies are required to understand the changing characteristics of radiation risk perception.

• Nuclear Engineering and Technology
• /
• v.54 no.7
• /
• pp.2592-2598
• /
• 2022

Research groups in the field of PET instrumentation are studying time-of-flight(TOF) technology to improve the signal-to-noise ratio of PET images. Scintillation light transport and collection plays an important role in improving the coincidence resolving time(CRT) of PET detector based on a pixelated crystal array. Four crystal arrays were designed by the different optical reflection configuration such as external reflectors and surface treatment on the CRT and compared with the light output, energy resolution and CRT. The design proposed in the study was composed of 8 × 8 LYSO crystal array consisted of 3 × 3 × 15 mm³ pixels. The entrance side was roughened while the other five surfaces were polished. Four sides of all crystal pixels were wrapped with ESR-film, and the entrance surface was covered by Teflon-tape. The design provided an excellent timing resolution of 210 ps and improved the CRT by 16% compared to the conventional method using a polishing treatment and ESR-film. This study provided a method for improving the light output and CRT of a pixelated scintillation crystal-based brain TOF PET detector. The proposed configuration might be an attractive detector design for TOF brain PET requiring fast timing performance with high cost-effectiveness.

• Journal of Radiation Protection and Research
• /
• v.42 no.2
• /
• pp.98-105
• /
• 2017

Background: By examining the safety issues involved in on-site training sessions conducted at specialized vocational high schools, and by analyzing the effects of non-destructive testing (NDT) safety training, this study aims to contribute to ensuring the general safety of high school students. Materials and Methods: Students who expressed an interest in participation were surveyed regarding current NDT training practices, as well as NDT safety training. A total of 361 students from 4 schools participated in this study; 37.7% (136 students) were from the Seoul metropolitan area and 62.3% (225 students) were from other areas. Results and Discussion: Of the respondents, 2.2% (8 students) reported having engaged in NDT. As a result of safety training, statistically significant improvements were observed in most areas, except for individuals with previous NDT experience. The areas of improvement included safety awareness, acquisition of knowledge, subjective knowledge levels, objective knowledge levels, and adjustments to existing personal attitudes. Conclusion: Even at absolutely necessary observation-only training sessions, it is crucial that sufficient safety training and additional safety measures be adequately provided.

• Nuclear Engineering and Technology
• /
• v.49 no.3
• /
• pp.569-575
• /
• 2017

One of the important requirements for the application of reduced-activation ferritic/martensitic (RAFM) steel is to retain proper mechanical properties under irradiation and high-temperature conditions. To simulate the yield strength and stress-strain curve of steels during high-temperature and irradiation conditions, a multiscale simulation method consisting of both microstructure and strengthening simulations was established. The simulation results of microstructure parameters were added to a superposition strengthening model, which consisted of constitutive models of different strengthening methods. Based on the simulation results, the strength contribution for different strengthening methods at both room temperature and high-temperature conditions was analyzed. The simulation results of the yield strength in irradiation and high-temperature conditions were mainly consistent with the experimental results. The optimal application field of this multiscale model was 9Cr series (7-9 wt.%Cr) RAFM steels in a condition characterized by 0.1-5 dpa (or 0 dpa) and a temperature range of $25-500^{\circ}C$.

• Nuclear Engineering and Technology
• /
• v.55 no.9
• /
• pp.3121-3125
• /
• 2023

Neutron conversion detectors that use ¹⁰B-enriched boron carbide are feasible alternatives to ³He-based detectors. We prepared boron carbide films at micron-scale thickness using direct-current magnetron sputtering. The structural characteristics of natural B₄C films, including density, roughness, crystallization, and purity, were analyzed using grazing incidence X-ray reflectivity, X-ray diffraction, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and scanning electron microscopy. A beam profile test was conducted to verify the practicality of the ¹⁰B-enriched B₄C neutron conversion layer. A clear profile indicated the high quality of the neutron conversion of the boron carbide layer.