Kori unit 1, the first PWR (Pressurized Water Reactor) in Korea, was permanent shut down in 2017. In Korea, according to the Nuclear Safety Act, the FDP (Final Decommissioning Plan) must be submitted within 5 years of permanent shutdown. According to NSSC Notice, the types, volumes, and radioactivity of solid radioactive wastes should be included in FDP chapter 9, Radioactive Waste Management, Therefore, in this study, the types depending on generation characteristics and radiological characterization methods and process of solid radioactive waste were analyzed. Solid radioactive waste depending on the characteristics of the generation was classified into reactor vessel and reactor vessel internal, large components, small metals, spent nuclear fuel storage racks, insulation, wires, concrete debris, scattering concrete, asbestos, mixed waste, soil, spent resins and filters, and dry active waste. Radiological characterization of solid radioactive waste is performed to determine the characteristics of radioactive contamination, including the type and concentration of radionuclides. It is necessary to ensure the representativeness of the sample for the structures, systems and components to be evaluated and to apply appropriate evaluation methods and procedures according to the structure, material and type of contamination. Therefore, the radiological characterization is divided into concrete and structures, systems and components, and reactor vessel, reactor vessel internal and bioshield concrete. In this study, the types depending on generation characteristics and radiological characterization methods and process of solid radioactive waste were analyzed. The results of this study can be used as a basis for the preparation of the FDP for the Kori unit 1.

The analysis of uranium migration is crucial for the accurate safety assessment of high-level radioactive waste (HLW) repository. Previous studies showed that the migration of the uranium can be affected by various physical and chemical processes, such as groundwater flow, heat transfer, sorption/ desorption and, precipitation/dissolution. Therefore, a coupled Thermal-Hydrological-Chemical (THC) model is required to accurately simulate the uranium migration near the HLW repository. In this study, COMSOL-PHREEQC coupled model was used to simulate the uranium migration. In the model, groundwater flow, heat transfer, and non-reactive solute transport were calculated by COMSOL, and geo-chemical reaction was calculated by PHREEQC. Sorption was primarily considered as geo-chemical reaction in the model, using the concept of two-site protolysis nonelctrostatic surface complexation and cation exchange (2 SP NE SC/CE). A modified operator splitting method was used to couple the results of COMSOL and PHREEQC. Three benchmarks were done to assess the accuracy of the model: 1) 1D transport and cation exchange model, 2) cesium transport in the column experiment done by Steefel et al. (2002), and 3) the batch sorption experiment done by Fernandes et al. (2012), and Bradbury and Baeyens (2009). Three benchmark results showed reliable matching with results from the previous studies. After the validation, uranium 1D transport simulation on arbitrary porewater condition was conducted. From the results, the evolution of the uranium front with sequentially saturating sites was observed. Due to the limitation of operator splitting method, time step effect was observed, which caused the uranium to sorbed at further sites then it should. For further study, 3 main tasks were proposed. First, precipitation/ dissolution will be added to the reaction part. Second, multiphase flow will be considered instead of single phase Darcy flow. Last, the effect of redox potential will be considered.

The design of the high-level radioactive waste (HLW) repository is made for isolating the HLW from the groundwater system by using artificial and natural barriers. Granite is usually considered to be a great natural barrier for the HLW repository in various countries including Sweden, Canada, and Korea due to its low hydraulic permeability. However, many fractures that can act as conduits for groundwater and radionuclides exist in granite. Furthermore, the decay heat generated by the HLW can induce groundwater acceleration through the fracture. Since the direction, magnitude, and lasting time of the heat-induced groundwater flow can be differed depending on the fracture geometry, the effect of fracture geometry on the groundwater flow around the repository should be carefully analyzed. In this study, groundwater models were conducted with various fracture geometries to quantify the effect of various properties of fractures (or fracture networks) on the heat-induced groundwater flow. In all models, the pressure around the repository only lasted for a short period after it peaked at 0.1 years. In contrast, the temperature lasted for 10,000 years after the disposal inducing the convective groundwater flow. Single fracture models with different orientations were conducted to evaluate the variations in groundwater velocities around the repository depending on the fracture slope. According to the results, the groundwater velocity on the fracture was the fastest when the regional groundwater flow direction and the fracture direction coincided. In double fracture models, various inclined fractures were added to the horizontal fracture. Due to the intersecting, the groundwater flow velocity showed a discontinuous change at the intersecting point. Lastly, the discrete fracture network models were conducted with different fracture densities, length distributions, and orientations. According to the modeling results, the groundwater flow was significantly accelerated when the fracture network density increased, or the average fracture length increased. However, the effect of the fracture orientation was not significant compared to the other two network properties.

DNA 바코드를 기반으로 하여 외국발 국내 입항 선박에서 검출되는 편승자 해충(hitchhiker insect pests)에 대한 모니터링을 수행하였다. 국내 입항 선박 조사는 2018년 6월 1일부터 2018년 9월 17일까지 약 109일간 111개 선박에 대해 실시하였다. 모니터링 대상 해충은 ‘보고잡기법(simply collecting method by hands)’으로 확보하였으며, 총 336개체 에 대해 종동정을 실시하였다. 그 결과, 확보 해충 중 농림축산검역본부에 ‘관리해충(Regulated insect pest)’으로 등재되어 있는 Noctua pronuba를 포함하여 총 13종 21개체(Amata formosae (Erebidae, Lepidoptera, 1개체), Arippara disticha (Pyralidae, Lepidoptera, 1개체), Chondracris rosea (Acrididae, Orthoptera, 4개체), Cyrtacanthacris tatarica (Acrididae, Orthoptera, 1개체), Euhampsonia serratifera (Notodontidae, Lepidoptera, 3개체), Lemyra rhodophilodes (Erebidae, Lepidoptera, 2개체), Lymantria xylina (Erebidae, Lepidoptera, 1개체), Malacosoma dentata (Lasiocampidae, Lepidoptera, 3개체), Neochauliodes meridionalis (Corydalidae, Megaloptera, 1개체), Noctua pronuba (Noctuidae, Lepidoptera, 1개체), Parasa pastoralis (Limacodidae, Lepidoptera, 1개체), Psilogramma lukhtanovi (Sphingidae, Lepidoptera, 1개체), Syntypistis viridipicta (Notodontidae, Lepidoptera, 1개체))의 국내 미서식종이 채집되었으며, 확보된 21개체 중 15개체는 살아있는 상태로 검출되었다. 특히, 관리해충인 N. pronuba의 경우, 싱가포르에서 광양을 거쳐 포항항으로 입항한 선박에서 검출되었는데, 이 종은 유럽을 비롯하여 중동 및 중앙아시아까지 서식하는 종으로 1990년대 북미 대륙에 침입한 것으로 확인된 바 있다. 이에 따라, N. pronuba를 비롯하여 현 조사에 확인된 국내 미서식 편승자 해충의 편승 유무에 대한 정밀 모니터링 뿐만 아니라 위 종들에 대한 체계적인 위험성 평가 역시 필요할 것으로 사료된다.

Insect pollinators of the endanger orchid Cypripedium japonicum were surveyed and identified during two years, as a part of a conservation project of the orchid at Jukyeup-san and Hwaak-san (Mt.), South Korea. In total 40 individuals of 16 species in 4 families were identified. The dominant family was Halictidae, and Lasioglossum exiliceps Vachal visited the most frequently C. japonicum during the surveys. The average visiting frequency was 2.5 individuals per hour and the highest 4.3, from 12:00 – 13:00 in a day. After 15:00 insects did not visit the flowers at all. However, all of the visiting insects were found to not carry a pollinium or pollens of the orchard on their bodies; pollen carryover by any of the visiting insects did not occur at all. The orchid seems to require certain pollinators in particular body thickness due to its unique pollination mechanism. The orchid has two exit route openings, around 1 cm in diametre, where the entrapped insects can exit and an anther is situated just in front of each opening. It was inferred that a pollen carrier should be around 1 cm in body thickness. Therefore, the candidate species as the proper pollen carriers can be Tetralonia nipponensis Perez, Xylocopa appendiculata circumvolans Smith and Bombus consobrinus Dahlbom among the surveyed visitors.

Attacin is a well-studied glycine-rich antibacterial protein in insect immune response, which has limitary antibacterial effect to some Gram-negative bacteria. A cDNA encoding the attacin gene was screened and isolated from the immunized larvae of the swallowtail butterfly, Papilio xuthus. The complete P. xuthus attacin cDNA is 949 nucleotides encoding a 250 amino acid precursor that contains a putative 18-residue signal peptide, a common 42-residue propeptide sequence and a presumed 190-residue mature protein with a theoretical mass of 19904.01 and a pI of 9.13. The putative mature protein of P. xuthus attacin showed 48%~52% and 24%~30% identity in amino acid sequences with that of lepidopteran and dipteran insects, respectively. The attacin transcript was induced at significant level after injection with bacterial lipopolysaccharide (LPS). Recombinant attacin was highly expressed in E. coli BL21 (DE3) cells by fusing with an N-terminal S-tag/thrombin cleavage site configuration protein to avoid the cell death during induction. The expressed fusion protein was purified by Ni-NTA immobilized metal affinity chromatography (IMAC). After desalting and cleavage with thrombin, the recombinant attacin was released and showed considerably antibacterial activity against Gram-negative bacteria, E. coli ML 35. Our results proved that this protein family with a potent antibacterial activity may play a role in the immune response of butterflies.

This study was conducted with the aim of evaluating the antibiotic effects of leaves, stems, and roots in yacon (Smallanthus sonchifolius). Antibacterial activity of leaf extract by disk diffusion method with Bacillus subtilis and Escherichia coli respectively showed 13.3 and 13.75mm diameters of clear zone. There was no significant difference between the stems and leaves. The minimum inhibitory concentration of leaves’ heating and agitation extraction showed a restrain of strain at 1mg/ml, but the stems and root extract did not appear. Yacon is a functional antibacterial material, and methanol extraction is more effective than water. This research was to investigate the growth stage of collection has the most effective antibacterial effects. It has collected yacon's leaves from June to October, which is an appropriate time for collection right before reaping. Yacon leaf has antibacterial effects on Bacillus subtilis, Escherichia coli, Enterococcus faecium, and Salmonella enteritifis. There were no significant differences by the growth stage of collection. Leaves collected in July are high in phenol which helps in sulfating activity works well considering the high scavenging capability of DPPH. Leaves collected in September are high in total flavonoid.