• Nuclear Engineering and Technology
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• v.46 no.1
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• pp.47-54
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• 2014

The protection of nuclear safety software is essential in that a failure can result in significant economic loss and physical damage to the public. However, software security has often been ignored in nuclear safety software development. To enforce security considerations, nuclear regulator commission recently issued and revised the security regulations for nuclear computer-based systems. It is a great challenge for nuclear developers to comply with the security requirements. However, there is still no clear software development process regarding security activities. This paper proposes an integrated development process suitable for the secure development requirements and system security requirements described by various regulatory bodies. It provides a three-stage framework with eight security activities as the software development process. Detailed descriptions are useful for software developers and licensees to understand the regulatory requirements and to establish a detailed activity plan for software design and engineering.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.2
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• pp.255-258
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• 2022

Three government bodies, that is, the Ministry of Science and ICT (MSIT), Ministry of Trade, Industry, and Energy (MOTIE), and Nuclear Safety and Security (NSSC), jointly established the Institute for Korea Spent Nuclear Fuel (iKSNF) in December 2020 to secure the management technologies for spent nuclear fuel (SNF). The objective of iKSNF is to successfully conduct the long-term research and development program of the 「Development of Core Technologies to Ensure Safety of Spent Nuclear Fuel Storage and Disposal System」. Our program, known as the first multi-ministry program in the nuclear field of Korea, mainly focuses on developing core technologies required for the long-term management of SNF, including those for safe storage and deep geological disposal of SNF. The program comprises three subprograms and seven key projects covering the storage, disposal, and regulatory sectors of SNF management. Our program will last from 2021 through 2029, with a budget of approximately four billion USD sponsored by MSIT, MOTIE, and NSSC.

• Biomedical Science Letters
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• v.8 no.3
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• pp.179-184
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• 2002

We investigated the morphological changes and TUNEL reaction of apoptotic cells in the liver of D-galactosamine (20 mg/mouse) and lipopolysaccharide (5 $\mu\textrm{g}$/mouse)-treated 30 mice (BALB/c), and in additioa also of apoptotic cells in kidney and spleen. The livers and other some organs of mice at 6, 12, 24, 48 and 72 hrs after treatment were collected and were fixed with 10% neutral formalin and paraffin sections were stained with hematoxylin-eosin or terminal deoxynucleotidly transferase-mediated dUTP nick end labeling (TUNEL) method. Morphological changes in apoptotic hepatocytes were chondensation of nuclei and density of cytoplasms, then the margination and pyknosis of chromatin, the formation of half-moon- or horse-shoe- or ship-like shapes of condensed chromatin mass, lastly formation of apoptotic bodies, disappearance of nuclear envelopes, decrease of stainability, then lysis and disappearance of apoptotic bodies. TUNEL positive reactions of hepatocytes were appeared first moderate in uncondensed hepatocytes, severe in condensed hepatocytes, moderate in chromatin-marginated hepatocytes. These reactions also were appeared moderate in hepatocytes with half-moon- or horse-shoe- or ship-like pyknotic chromatin mass or apoptotic bodies, and mild or negative in hepatocytes with lysed apoptotic bodies or with disappeared nuclear envelopes. Consequently these results suggested that TUNEL positive reactions of hepatocytes appeared at more early stages than appearance of chromatin condensation and disappeared at more early stage than disappearance of histological findings of apoptosis. We also confirmed that the differentiation of apoptotic cells from normal healthy cells of Kupffer cells and vascular endothelial cells in liver, reticular cells and lymphocytes in spleen and epithelial cells of tubules and ducts in kidney was impossible in H-E preparations but was possible in TUNEL preparations.

• Nuclear Engineering and Technology
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• v.40 no.7
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• pp.551-560
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• 2008

Radiation has stochastic aspects in its generation, its choice of interaction mode during traveling in media, and its impact on living bodies. In certain circumstances, like in high dose environments resulting from low-LET radiation, the variance in its impact on a target volume is negligible. On the contrary, in low dose environments, especially when they are attributed to high-LET radiation, the impact on the target carries with it a large variance. This variation is more significant for smaller target volumes. Microdosimetric techniques, which have been developed to estimate the distribution of radiation energy deposited to cellular and subcellular-sized targets, contrast with macrodosimetric techniques which count only the average value. Since cells and DNA compounds are the critical targets in human bodies, microdosimetry, or dose estimation by microscopic approach, helps one better analyze the biological effects of radiation on the human body. By utilizing microbeam systems designed for individual cell irradiation, scientists have discovered that human cells exhibit radiosensitive reactions without being hit themselves (bystander effect). During the past 10 or more years, a new therapeutic protocol using discontinuous multiple micro-slit beams has been investigated for its clinical application. It has been suggested that the beneficial bystander effect is the essence of this protocol.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.2
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• pp.102-111
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• 2007

Dementia is a major burden for many countries including South Korea, where life expectancy is continuously growing and the proportion of aged people is rapidly growing. Neurodegenerative disorders, such as, Alzheimer disease, dementia with Lewy bodies, frontotemporal dementia, Parkinson disease, progressive supranuclear palsy, corticobasal degeneration, Huntington disease, can cause dementia, and cerebrovascular disease also can cause dementia. Depression or hypothyroidism also can cause cognitive deficits, but they are reversible by management of underlying cause unlike the forementioned dementias. Therefore these are called pseudodementia. We are entering an era of dementia care that will be based upon the identification of potentially modifiable risk factors and early disease markers, and the application of new drugs postpone progression of dementias or target specific proteins that cause dementia. Efficient pharmacologic treatment of dementia needs not only to distinguish underlying causes of dementia but also to be installed as soon as possible. Therefore, differential diagnosis and early diagnosis of dementia are utmost importance. F-18 FDG PET is useful for clarifying dementing diseases and is also useful for early detection of the diseases. Purpose of this article is to review the current value of FDG PET for dementing diseases including differential diagnosis of dementia and prediction of evolving dementia.

• Tribology and Lubricants
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• v.35 no.4
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• pp.229-236
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• 2019

This study investigates the stress singularity that occurs at the contact edge of three bodies in a frictional complete contact. We use the asymptotic analysis method, wherein we constitute an eigenvalue problem and observe the eigenvalue behavior, which we use to obtain the order of the stress singularity. For the present geometry of three bodies in contact, a contact between a cracked indenter and half plane is considered. This is a typical geometry of the PCMI problem of a nuclear fuel rod. Thus, this paper, specifically presents the characteristics of the PCMI problem from the perspective of stress singularity. Consequently, it is noted that the behavior of the stress singularity varies with the difference in the crack angle, coefficient of friction, and material dissimilarity, as is observed in a frictional complete contact of two bodies. In addition, we find that the stress singularity changes essentially linearly with respect to the coefficient of friction, regardless of the variation in the crack angle and material dissimilarity. Concurrently, we find the order of singularity to be 0.5 at a certain coefficient of friction, irrespective of the crack angle, which we also observe in the crack problem of a homogeneous and isotropic body. The order of singularity can also exceed 0.5 in the frictional complete contact problem of three bodies. This implies that the propensity for failure when three bodies are in frictional complete contact can be even worse than that in case of a failure induced by a crack.

• Parasites, Hosts and Diseases
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• v.23 no.2
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• pp.269-284
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• 1985

The metabolism of Entamoeba histolytica would be affected by various environmental factors, and alteration of the environment was known to afEect the fine structure of 5. histolytica. The present study was designed electronmicroscopically to investigate the ultrastructure and enzyme activities in the aEonic and conventional strains of 5. histolytica. The trophozoites of axenically cultivated HK-9 strain and conventional YS-27 and YS-49 strains of 5. histolytica were collected and liKed with 4% paraformaldehyde/0.1M cacodylate buffier(pH 74), After washing them by centrifugation, 1% warm agar was added in the sediment. Solidified agar with the trophozoites was cut into $lmm^3$ cubes, and incubated in the various substrates to observe enzyme activities. Then, the specimen was post-fixed with 3% glutaraldehyde/0.1M cacodylate buffer (PH 7.4) and 1% osmium tetroBide/0.1M cacodylate buffier (pH 7.4) , dehydrated in ascending ethanol series and embedded in epoxy resin. These were sectioned on an ultramicrotome and observed with a transmission electronmicroscope. The procedures for the observation of the fine structure were same as the above, except for the incubation in the substrate. The sections were stained with uranyl acetate and lead citrate. For the observation of the surface of the amoebae, scanning-electronmicroscopy was carried out. The results obtained in the present study are summarized as follows: 1. The fuzzy coat around double-layered plasma membrane of 5. histolytica was more irregularly and densely distributed in the conventional strains (YS-27, YS-49 strains) than in the axonic strain (HK-9 strain). 2. The endosomes, button bodies and chromatin material were surrounded by a double-layered nuclear membrane having scattered nuclear fores. The paranuclear body, mono- or double-layered vacuoles, vacuolar membrane whorls, rosette-like cylindrical bodies, aggregation of cylindrical bodies and helical bodies were found in the cytoplasm of the amoebae. Helical bodies and glycogen granules were generally abundant, while a few smooth endoplasmic reticula were observed in the cytoplasm. 3. Alkaline phosphatase activity was mainly demonstrated in the plasma membrane, limiting membranes of vacuoles and smooth endoplasmic reticula. ATPase activity was observed in the nucleus, limiting membranes of vacuoles and vacuolar membrane whorls. 4. Acid phosphatase activity was commonly demonstrated in the limiting membranes an contents of vacuoles, Iysosome-like organelles, plasma membrane and the button bodies in the nucleus. The activity was more weakly demonstrated in the HK-9 strain than in the other conventional strains of 5. histolytica. No peroBidase activity was observed in the amoeba strains employed in the present study. 5. With a scanning electron-microscope, no distinct structural differences were observed between the amoeba strains. All the trophozoite forms of the amoebae showed crater-like depressions and rugged features on the outer surface.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.12 no.1
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• pp.56-61
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• 2016

After Japanese Fukushima nuclear power plant accident caused by the beyond design basis earthquake and tsunami, it has turned to be a major challenge for nuclear safety. IAEA, US NRC and EU have provided new safety design standards for beyond design basis event, Domestic regulatory bodies have also enacted guidances for licensees and applicants on additional methods related to beyond design basis events. This paper describes several evaluation methods for applying to nuclear power plants piping for beyond design basis earthquake. As a results, energy method based on the absorbed energy on nuclear power plant, deterministic method following design code and theory, experience method considering past earthquake data and information and probabilistic methods similar to probabilistic risk assessment were reviewed.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2523-2533
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• 2021

In the last decade, the best estimate plus uncertainty methodologies in nuclear technology and nuclear power plant design have become a trending topic in the nuclear field. Since BEPU was allowed for licensing purposes by the most important regulator bodies, different uncertainty assessment methods have become popular, overall non-parametric methods. While non-parametric tolerance regions can be well stated and used in uncertainty quantification for licensing purposes, the propagation of the uncertainty through different codes (multi-scale, multiphysics) in cascade needs a better depiction of uncertainty than the one provided by the tolerance regions or a probability distribution. An alternative method based on the parametric or distributional probability boxes is used to perform uncertainty quantification and propagation regarding statistic uncertainty from one code to another. This method is sample-size independent and allows well-defined tolerance intervals for uncertainty quantification, manageable for uncertainty propagation. This work characterizes the distributional p-boxes behavior on uncertainty quantification and uncertainty propagation through nested random sampling.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2666-2675
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• 2024

This study explores the potential for tritium production in North Korea's 5MWe graphite-moderated reactor, a facility primarily associated with nuclear weapons material production. While existing research on these reactors has largely centered on plutonium, our focus shifts to tritium, a crucial element in boosted fission bombs. Utilizing the MCNP6 code for simulations, the results estimate that North Korea can possibly produce approximately 7-12 g of tritium annually. This translates to the potential production of 1-3 boosted fission bombs each year. By incorporating tritium production into assessments of North Korea's nuclear capabilities, our methodology provides insights into the dynamics of the country's nuclear force, revealing a more diversified and complex composition than previously assumed. The findings significantly aid policymakers, regulatory bodies, and researchers in comprehending potential proliferation risks associated with graphite-moderated reactors and in developing strategies to address the nuclear threat emanating from North Korea.