• Korea Science and Art Forum
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• v.6
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• pp.67-78
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• 2010

The purpose of this study was to examine the educational methods and the educational effects using the cloud chamber in order to help young people to understand the nuclear energy and the ionizing radiation. In this study, we surveyed not only the history and the value of the cloud chamber as an hands-on exhibit in the science museum, but the case study on the nuclear hands-on education and the nuclear out-of-school education using the cloud chamber. And we analysed the satisfaction degree of participants in the out-of-school education using the cloud chamber in the science museum.

• The Mathematical Education
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• v.22 no.3
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• pp.27-31
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• 1984

In this paper we summarize the characteristic properties of the nuclear space, and then try to establish the relation between Hopf's extension theorem and nuclear space on $\sigma$-Hilbert space.

• Journal of Radiation Protection and Research
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• v.37 no.4
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• pp.173-176
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• 2012

Quality Management is a recent phenomenon. This is applied to products or services, with an objective to deliver high quality, reliable, worthy, enduring, product or service. The process is considered to have four main components: quality planning, quality control, quality assurance and quality improvement. Focusing on quality control and quality assurance leads to achieving quality management or ensures that an organization or product is consistent. In this paper, the applicable international standard for learning services and for the organization for education and training (learning service provider) is discussed and also the procedure to implement the management system.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1322-1332
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• 2019

In this paper, we systematically investigated the influence of some selected ligands on the U-phosphate precipitation induced by soil bacteria. These organics are widely ranging from acetate, lactate, salicylate and citrate to oxalate. The results revealed that uranium could be biomineralized on bacteria as $UO_2HPO_4{\cdot}4H_2O$ or $(UO_2)_3(PO_4)_2{\cdot}4H_2O$. The influence of organic ligands on the biomineralization had clear-cut correlations with its complexation abilities to uranyl. It was clearly found that the U-phosphate biomineralization was affected noticeably by the strong ligands (oxalate and citrate). Further study discovered that when the organic ligands were uncompetitive with biotic $PO_4^{3-}$ for uranyl, the transformation of uranyl species from ${\beta}-UO_2(OH)_2$ colloidal particles to free $UO_2^{2+}$-ligands ions could facilitate the U-phosphate biomineralization. However, when the organic ligands competed with biotic $PO_4^{3-}$ for uranyl, the U-phosphate biomineralization were inhibited. Our results highlight the importance of complex interactions of strong organic ligands with uranyl during the bacterial precipitation of U-P compounds and thus for the mobilization and immobilization of radio-nuclides in the nature.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4660-4670
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• 2022

Hydroxyurea (HU) is a novel salt-free reductant used potentially for the separation of U/Pu in the advanced PUREX process. In this work, the radiation stability of HU were systematically investigated in solution by examining the effects of the type of rays (α, β, and γ irradiations), the absorbed dose (10-50 kGy), and the HNO₃ concentration (0-3 mol L^-1). The influence degree on HU radiolysis rates followed the order of the absorbed dose > the ray type > the HNO₃ concentration, but the latter two had moderate effects on HU radiolysis products where NH₄⁺ and NO₂^- were found to be the most abundant ones, suggesting that the differences of α, β, and γ rays should be considered in the study of irradiation effects. The radiolysis mechanism was explored using density functional theory (DFT) calculations, and it proposed the dominant radiolysis paths of HU, indicating that the radiolysis of HU was mainly a free radical reaction among ·H, e_aq^-, H₂O, intermediates, and the radiolytic free radical fragments of HU. The results reported here provide valuable insights into the mechanistic understanding of HU radiolysis under α, β, and γ irradiations and reliable data support for the application of HU in the reprocessing of spent fuel.

• Journal of Science Education
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• v.37 no.2
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• pp.294-309
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• 2013

This study addressed the awareness of social issues related to science of future elementary school teachers. Fukushima Nuclear Power Plant Accident was used by concrete issue connected with SSI for this study. Twelve second-year students attending a university of education participated in the study, who were taking a class of science teacher preparation at that time that consists of the content of the elementary science education courses. The study revealed that all the pre-service elementary teachers recognized Fukushima Nuclear Power Plant Accident and received such information through various medias. In particular, they were receiving more information about the Nuclear Power Plant Accident through the internet than any other media by using the internet a lot, and also gained additional information through the internet. However, despite the fact that they recognized Nuclear Power Plant Accident, they neither had much information about it nor had been interested in SSI such as the Nuclear Power Plant Accident. Moreover, they had been basically uneducated about SSI. Despite of having no interest in SSI such as Nuclear Power Plant Accident, the study revealed that the pre-service elementary teachers recognized that scientific problems such as Nuclear Power Plant Accident may affect a society closely. In addition, they together sympathized with the point that SSI education should be applied on the current education courses by identifying the problem in application. As the study revealed above, the application of SSI education to the formal education courses as well as more lively research on that subject is very important and urgent for boosting interest in science subjects and enlightening the nature of science that is one of the objectives of science education.

• Nuclear Engineering and Technology
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• v.50 no.4
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• pp.599-605
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• 2018

Fault diagnosis depends critically on the selection of sensors monitoring crucial process variables. Boolean network (BN) is composed of nodes and directed edges, where the node state is quantized to the Boolean values of True or False and is determined by the logical functions of the network parameters and the states of other nodes with edges directed to this node. Since BN can describe the fault propagation in a sensor network, it can be applied to propose sensor selection strategy for fault diagnosis. In this article, a sufficient condition for parameter identifiability of BN is first proposed, based on which the sufficient condition for fault identifiability of a sensor network is given. Then, the fault identifiability condition induces a sensor selection strategy for sensor selection. Finally, the theoretical result is applied to the fault diagnosis-oriented sensor selection for a nuclear heating reactor plant, and both the numerical computation and simulation results verify the feasibility of the newly built BN-based sensor selection strategy.

• Nuclear Engineering and Technology
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• v.52 no.8
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• pp.1706-1713
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• 2020

Functionally gradient material (FGM) is promisingly effective in mitigating the thermal stress between plasma facing materials (PFM) and structural materials. However, the corresponding research with respect to W/V FGM has not been reported yet. In this work, we firstly report the successful fabrication of W/V FGM by a combined technology of mechanical alloying (MA) and spark plasma sintering (SPS). The microhardness and microstructure of the consolidated sample were both investigated. W/V stacks show significantly enhanced microhardness (>100%) compared with pure W plate, which is beneficial to the integral strength of the hybrid structure. Furthermore, we clarify that the different ductility of W and V should be carefully considered, otherwise W/V powder might aggregate and lead to the formation of compositional segregation, and simultaneously unmask the impact of V proportion on the distribution of second phase in W-V binary alloy system. This work provides an innovative approach for obtaining W-V connections with much better performance.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.190-197
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• 2019

W-K-TiC alloys with different titanium carbide concentrations (0.05, 0.1, 0.25, 0.5, 1, 2) wt.% were fabricated through Mechanical Alloying and Spark Plasma Sintering. The effects of the addition of nano-scaled TiC particles on the relative density, Vickers micro-hardness, microstructure, crystal information, thermal shock resistance, and tensile strength were investigated. It is revealed that the doped TiC nano-particles located at the grain boundaries. The relative density and Vickers micro-hardness of W-K-TiC alloys was enhanced with TiC addition and the highest Vickers micro-hardness is 731.55. As the TiC addition increased from 0.05 to 2 wt%, the room-temperature tensile strength raised from 141 to 353 MPa. The grain size of the W-K-TiC alloys decreased sharply from $2.56{\mu}m$ to 330 nm with the enhanced TiC doping. The resistance to thermal shock damage of W-K-TiC alloys was improved slightly with the increased TiC addition.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.310-323
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• 2023

The k-eigenvalue neutronics/thermal-hydraulics coupling calculation is a key issue for reactor design and analysis. Jacobian-free Newton-Krylov (JFNK) method, featured with super-linear convergence rate and high efficiency, has been attracting more and more attention to solve the multi-physics coupling problem. However, it may converge to the high-order eigenmode because of the multiple solutions nature of the k-eigenvalue form of multi-physics coupling issue. Based on our previous work, a modified JFNK with a line search method is proposed in this work, which can find the fundamental eigenmode together with thermal-hydraulics feedback in a wide range of initial values. In detail, the existing modified JFNK method is combined with the line search strategy, so that the intermediate iterative solution can avoid a sudden divergence and be adjusted into a convergence basin smoothly. Two simplified 2-D homogeneous reactor models, a PWR model, and an HTR model, are utilized to evaluate the performance of the newly proposed JFNK method. The results show that the performance of this proposed JFNK is more robust than the existing JFNK-based methods.