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A Study on Reusable Metal Component as Burnable Absorber Through Monte Carlo Depletion Analysis
Muth, Boravy,Alrawash, Saed,Park, Chang Je,Kim, Jong Sung Korean Radioactive Waste Society 2020 방사성폐기물학회지 Vol.18 No.4
After nuclear power plants are permanently shut down and decommissioned, the remaining irradiated metal components such as stainless steel, carbon steel, and Inconel can be used as neutron absorber. This study investigates the possibility of reusing these metal components as neutron absorber materials, that is burnable poison. The absorption cross section of the irradiated metals did not lose their chemical properties and performance even if they were irradiated over 40-50 years in the NPPs. To examine the absorption capability of the waste metals, the lattice calculations of WH 17×17 fuel assembly were analyzed. From the results, Inconel-718 significantly hold-down fuel assembly excess reactivity compared to stainless steel 304 and carbon steel because Inconel-718 contains a small amount of boron nuclide. From the results, a 20wt% impurity of boron in irradiated Inconel-718 enhances the excess reactivity suppression. The application of irradiated Inconel-718 as a burnable absorber for SMR core was investigated. The irradiated Inconel-718 impurity with 20wt% of boron content can maintain and suppress the whole core reactivity. We emphasize that the irradiated metal components can be used as burnable absorber materials to control the reactivity of commercial reactor power and small modular reactors.
곽정권,Boravy Muth,양현우,박창제,강우승,김선재 대한금속·재료학회 2021 대한금속·재료학회지 Vol.59 No.12
Radiation causes damage to the human body, the environment, and electronic equipment. Shielding against neutron and gamma rays is particularly difficult because of their strong ability to penetrate materials. Conventional gamma ray shields are typically made of materials containing Pb. However, they pose problems in that Pb is a heavy metal, and human poisoning and/or pollution can result from the manufacturing, use, and disposal of these materials. In addition, neutron rays are shielded by materials rich in H2 or concrete. In the case of the latter, the manufacturing cost is high. Thus, it is necessary to develop a new multilayer structure that can shield against both neutron and gamma rays. We set up a simulation model of a multilayered structure consisting of metal hydrides and heavy metals, and then evaluated the simulations using Monte Carlo N-Particle Transport Code. Monte Carlo simulation is an accurate method for simulating the interaction between radiation and materials, and can be applied to the transport of radiation particles to predict values such as flux, energy spectrum, and energy deposition. The results of the study indicated the multilayer structure of ZrH2, U, and W could shield both neutron and gamma rays, thus showing potential as a new shielding material to replace Pb and concrete.
조재은,정봉광,장태희,손운목,Muth Sinuon,채종일 대한기생충학ㆍ열대의학회 2020 The Korean Journal of Parasitology Vol.58 No.4
Echinostoma mekongi n. sp. (Digenea: Echinostomatidae) is described based on adult flukes collected from humans residing along the Mekong River in Cambodia. Total 256 flukes were collected from the diarrheic stool of 6 echinostome egg positive villagers in Kratie and Takeo Province after praziquantel treatment and purging. Adults of the new species were 9.0–13.1 (av. 11.3) mm in length and 1.3–2.5 (1.9) mm in maximum width and characterized by having a head collar armed with 37 collar spines (dorsal spines arranged in 2 alternative rows), including 5 end group spines. The eggs in feces and worm uterus were 98–132 (117) μm long and 62–90 (75) μm wide. These morphological features closely resembled those of Echinostoma revolutum, E. miyagawai, and several other 37-collar-spined Echinostoma species. However, sequencing of the nuclear ITS (ITS1-5.8S rRNA-ITS2) and 2 mitochondrial genes, cox1 and nad1, revealed unique features distinct from E. revolutum and also from other 37-collar-spined Echinostoma group available in GenBank (E. bolschewense, E. caproni, E. cinetorchis, E. deserticum, E. miyagawai, E. nasincovae, E. novaezealandense, E. paraensei, E. paraulum, E. robustum, E. trivolvis, and Echinostoma sp. IG). Thus, we assigned our flukes as a new species, E. mekongi. The new species revealed marked variation in the morphology of testes (globular or lobulated), and smaller head collar, collar spines, oral and ventral suckers, and cirrus sac compared to E. revolutum and E. miyagawai. Epidemiological studies regarding the geographical distribution and its life history, including the source of human infections, remain to be performed.
<i>Echinostoma revolutum</i> Infection in Children, Pursat Province, Cambodia
Sohn, Woon-Mok,Chai, Jong-Yil,Yong, Tai-Soon,Eom, Keeseon S.,Yoon, Cheong-Ha,Sinuon, Muth,Socheat, Duong,Lee, Soon-Hyung Centers for Disease Control and Prevention 2011 Emerging infectious diseases Vol.17 No.1
<P>To determine the prevalence of helminthic infections in Pursat Province, Cambodia, we tested fecal specimens from 471 children, 10–14 years of age, in June 2007. The prevalence of infection with echinostome flukes ranged from 7.5% to 22.4% in 4 schools surveyed. Adult worms were identified as <I>Echinostoma revolutum.</I></P>
Echinostoma ilocanum Infection in Oddar Meanchey Province, Cambodia
Woon-Mok Sohn,Hyeong-Jin Kim,Tai-Soon Yong,Keeseon S. Eom,Hoo-Gn Jeong,Jae-Kwang Kim,A-Reum Kang,Mok-Ryun Kim,Jung-Mi Park,Soo-Hyeon Ji,Muth Sinuon,Duong Socheat,Jong-Yil Chai 대한기생충학열대의학회 2011 The Korean Journal of Parasitology Vol.49 No.2
Fecal examinations using the Kato Katz technique were performed on a total of 1,287 villagers (945 students and 342 general inhabitants) of Oddar Meanchey Province, Cambodia in May 2007 and November 2009. The overall intestinal helminth egg positive rate was 23.9%, and the most prevalent helminth species was hookworms (21.6%). Other helminth eggs detected included echinostomes (1.0%), Enterobius vermicularis (0.8%), small trematode eggs (0.7%), which may include Opisthorchis viverrini and Haplorchis spp., and Hymenolepis nana (0.4%). In order to recover adult echinostomes, we treated 2 patients with 10-15 mg/kg praziquantel and purged. Total 14 adult echinostomes, 1 and 13 worms from each patient, were collected. The echinostomes characteristically had 49-51 collar spines and 2 round or slightly lobated testes. They were identified as Echinostoma ilocanum (Garrison, 1908) Odhner, 1911. So far as literature are concerned, this is the first record on the discovery of human E. ilocanum infection in Cambodia.