• Title/Summary/Keyword: Bioshield

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A Study on the Inventory Estimation for the Activated Bioshield Concrete of KRR-2 (연구로 2호기 방사화 수조 콘크리트의 재고량 평가에 관한 연구)

  • Hong, Sang Bum;Seo, Bum Kyoung;Cho, Dong Keun;Jeong, Gyeong Hwan;Moon, Jei Kwon
    • Journal of Radiation Protection and Research
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    • v.37 no.4
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    • pp.202-207
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    • 2012
  • The radioactivity inventory significantly affects all steps of decommissioning projects including planning, cost estimation, risk assessment, waste management and site remediation. The decommissioning project of the KRR-2 was completed in 2009 and a large amount of activated concrete waste was generated. The bioshield concrete, containing minute amount of impurity elements, was activated by neutron reaction during the operation of the reactor. A variety radionuclides was generated in the concrete, including $^3H$, $^{14}C$, $^{55}Fe$, $^{60}Co$ $^{63}Ni$, $^{134}Cs$, $^{152}Eu$ and $^{154}Eu$. In this paper, the comparison between the calculated results and previous measured results was carried out to estimate the inventory of the bioshield concrete of the KRR-2. The combined computer codes of MCNP5 and ORIGEN 2.1 for calculation of the distribution of neutron flux, cross-section and generation of radionuclides were used. The results were shown that 99.8% of the total radioactivity of $^3H$, $^{55}Fe$, $^{60}Co$ and $^{152}Eu$ in the bioshield concrete 12 years after shutdown. The effects on the variation of inventory were analysed depending on the operation periods and the cooling times in the bioshield concrete.

Factors affecting the occurrence of wilt of strawberry caused by Fusarium oxysporum f. sp. fragariae in Korea

  • Nam, Myeong-Hyeon;Jung, Suck-Ki;Kim, Hong-Gi;Song, Jeong-Young;Yoo, Sung-Joon
    • Proceedings of the Korean Society of Plant Pathology Conference
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    • 2003.10a
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    • pp.118-118
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    • 2003
  • The occurrence of Fusarium wilt in strawberry fields in Korea was assessed from 2001 to 2003. Fusarium wilt was found from June to August in nursery beds, from September to October after planting in production beds, and from January to March during harvest. The symptoms seen were root rots, discolored vascular tissue in the crown and deformation and yellowing of central leaflets. The disease occurred in up to 30% of plants in 37 of 214 fields surveyed. Fusarium of sporum Schlecht. ex Fr. f. sp. fragariae was frequently isolated from cvs. Dochiodome, Maehyang, Redpearl, Samaberry and Akihime. Factors affecting the occurrence of Fusarium wilt were investigated; infested soils had high salt concentrations, low pH, OM, average P2O5 and exchangeable. Fusarium wilt was more frequent following conventional basal fertilization than after non-nitrogen basal fertilization and more frequent following the use of NH4-N than after NO3-N.

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Evaluation of genetic affinities among Fusarium oxysporum f. sp. fragariae by RAPD and rDNA RFLP

  • Gopal Nagarajan;Nam, Myeong-Hyeon;Lee, Yun-Soo;Lee, Woo-Chung;Yoo, Sung-Joon;Song, Jeong-Young;Kim, Hong-Gi
    • Proceedings of the Korean Society of Plant Pathology Conference
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    • 2003.10a
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    • pp.116.1-116
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    • 2003
  • Fusarium oxysporum f. sp. fragariae is a fungal pathogen causing wilt disease on strawberry. The RAPD and RFLP of IGS region of rDNA were used to identify genetic affinity among 22 isolates of F. oxysporum f. sp. fagariae obtained from various location of major strawberry cultivating areas in Korea. Approximately 2.6kb DNA fragment was amplified with primer CNS1 and CNL12, and polymorphisms were observed with Avail and HinfI. A dendrogram was constructed using the UPGMA for cluster analysis. Eight distinct groups were clustered based on the banding pattern obtained from RAPD and rDNA RFLP. There was high level genetic variation among Korean isolates of Fusarium of sporum f. sp. fragariae.

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Safety Assessment for the self-disposal plan of clearance radioactive waste after nuclear power plant decommissioning (원전해체후 규제해제 콘크리트 방사성 폐기물의 자체처분을 위한 안전성 평가)

  • Choi, YoungHwan;Ko, JaeHun;Lee, DongGyu;Kim, HaeWoong;Park, KwangSoo;Sohn, HeeDong
    • Journal of Energy Engineering
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    • v.29 no.1
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    • pp.63-74
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    • 2020
  • The Kori-Unit 1 nuclear power plant, which is scheduled for decommissioning after permanent shutdown, is expected to generate a large amount of various types of radioactive waste during decommissioning process. For concrete radioactive waste, which is expected to occupy the most amount, it is important to analyze the current waste disposal status and legal limitations and to prepare an appropriate and efficient disposal method. Concrete radioactive waste is waste of various levels, of which the clearance level is bioshield concrete. In this paper, clearance radioactive waste safety evaluation was performed using the RESRAD code, which is a safety evaluation code, based on the activation evaluation results for the wastes with the clearance level. The clearance scenario of the target radioactive waste was selected and the individual's exposure dose was calculated at the time of clearance to determine whether the clearance criteria limit prescribed by the Nuclear Safety Act was satisfied. As a result of the evaluation, the results showed significantly lower results and satisfied the criteria value. Based on the results of this clearance safety assessment, the appropriate disposal method for bioshield concrete, which are the clearance wastes of subject of deregulation, was suggested.

Genetic Variation in Fusarium oxysporum f. sp. fagariae Populations Based RAPD and rDNA RFLP Analyses

  • Nagaraian, Gopal;Nam, Myeong-Hyeon;Song, Jeong-Young;Yoo, Sung-Joon;Kim, Hong-Gi
    • The Plant Pathology Journal
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    • v.20 no.4
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    • pp.264-270
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    • 2004
  • Fusarium oxysporum f. sp. fragariae is a fungal pathogen causing strawberry wilt disease. The random amplified polymorphic DNA (RAPD) and restriction fragment length polymorphisms (RFLPs) of intergenic spacer (IGS) region of rDNA were used to identify genetic variation among 22 F. oxysporum f. sp. fragariae isolates. All isolates could be distinguished from each other by RAPD analysis and RFLP of 2.6 kb amplified with primer CNS1 and CNL12 for IGS region of rDNA. Cluster analysis using UPGMA showed eight distinct clusters based on the banding patterns obtained from RAPD and rDNA RFLP. These results indicate that F. oxysporum f. sp. fragariae isolates are genetically distinct from each other, There was a high level genetic variation among F. oxysporum f. sp. fragariae.

Vegetative Compatibility Group of Fusarium oxysporum f. sp. radicis-lycopersici in Korea

  • Kim, Sung-Ho;Kim, Jong-Tae;Jang, Chang-Soon;Yoo, Sung-Jun;Kim, Hong-Gi
    • The Plant Pathology Journal
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    • v.21 no.3
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    • pp.214-220
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    • 2005
  • Vegetative compatibility groups (VCGs) of Fusarium oxysporum f. sp. radicis-lycopersici isolates collected from tomatoes in Korea were analyzed to determine the genetic characteristics and compared to those of foreign isolates. In comparison of VCG specificity with foreign VCG subgroup testers, Korean isolates were revealed to be VCG 0094 and to be similar to those of Israel and Florida, USA having a 'Universal' property. Results of this study will contribute the effective control of disease through precise estimation of fungal damage, the prediction of new pathogenic isolates appearance, and the movement of foreign pathogens.