• Title/Summary/Keyword: radioactive materials

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A Study on Annual Atmospheric Dispersion Factors Between Continuous and Purge Releases of Gaseous Radioactive Effluents

  • Kim, Na-Hyun;Hwang, Won-Tae;Kim, Chang-Lak
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.19 no.2
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    • pp.177-186
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    • 2021
  • Radioactive materials from nuclear power facilities can be released into the atmosphere through various channels. Recently, the dispersion of radioactive materials has become critical issue in Korea after Kori Unit 1 and Wolsong Unit 1 were permanently shut down. In this study, annual atmospheric dispersion factors were compared based on the continuous release and purge release using the XOQDOQ computer program, a method for calculating atmospheric dispersion factors at commercial nuclear power stations. The meteorological data analyzed in this study was based on the Shin Kori nuclear power meteorological tower which has the largest operating nuclear power plants in Korea, for three years (from 2008 to 2010). The analysis results of the dispersion factor of the radioactive material release obtained using the XOQDOQ program showed that the difference between the continuous release and purge release was within two times. This study will be valuable helpful for revealing the uncertainty of the predictive atmospheric dispersion factor to achieve regulation.

Electrochemical oxidation of sodium dodecylbenzenesulfonate in Pt anodes with Y2O3 particles

  • Jung-Hoon Choi;Byeonggwan Lee;Ki-Rak Lee;Hyun Woo Kang;Hyeon Jin Eom;Seong-Sik Shin;Ga-Yeong Kim;Geun-Il Park;Hwan-Seo Park
    • Nuclear Engineering and Technology
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    • v.54 no.12
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    • pp.4441-4448
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    • 2022
  • The electrochemical oxidation process has been widely studied in the field of wastewater treatment for the decomposition of organic materials through oxidation using ·OH generated on the anode. Pt anode electrodes with high durability and long-term operability have a low oxygen evolution potential, making them unsuitable for electrochemical oxidation processes. Therefore, to apply Pt electrodes that are suitable for long-term operation and large-scale processes, it is necessary to develop a new method for improving the decomposition rate of organic materials. This study introduces a method to improve the decomposition rate of organic materials when using a Pt anode electrode in the electrochemical oxidation process for the treatment of organic decontamination liquid waste. Electrochemical decomposition tests were performed using sodium dodecylbenzenesulfonate (SDBS) as a representative organic material and a Pt mesh as the anode electrode. Y2O3 particles were introduced into the electrolytic cell to improve the decomposition rate. The decomposition rate significantly improved from 21% to 99%, and the current efficiency also improved. These results can be applied to the electrochemical oxidation process without additional system modification to enhance the decomposition rate and current efficiency.

Radiological Safety Assessment for a Near-Surface Disposal Facility Using RESRAD-ONSITE Code

  • Jang, Jiseon;Kim, Tae-Man;Cho, Chun-Hyung;Lee, Dae Sung
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.19 no.1
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    • pp.123-132
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    • 2021
  • Radiological impact analyses were carried out for a near-surface radioactive waste repository at Gyeongju in South Korea. The RESRAD-ONSITE code was applied for the estimation of maximum exposure doses by considering various exposure pathways based on a land area of 2,500 ㎡ with a 0.15 m thick contamination zone. Typical influencing input parameters such as shield depth, shield materials' density, and shield erosion rate were examined for a sensitivity analysis. Then both residential farmer and industrial worker scenarios were used for the estimation of maximum exposure doses depending on exposure duration. The radiation dose evaluation results showed that 60Co, 137Cs, and 63Ni were major contributors to the total exposure dose compared with other radionuclides. Furthermore, the total exposure dose from ingestion (plant, meat, and milk) of the contaminated plants was more significant than those assessed for inhalation, with maximum values of 5.5×10-4 mSv·yr-1 for the plant ingestion. Thus the results of this study can be applied for determining near-surface radioactive waste repository conditions and providing quantitative analysis methods using RESRAD-ONSITE code for the safety assessment of disposing radioactive materials including decommissioning wastes to protect human health and the environment.

A Study on Effective Management Scheme for Soil and Groundwater Contaminated by Radioactive Materials Due to Nuclear Accidents (원전사고에 따른 토양.지하수 방사성오염의 효과적인 관리 연구)

  • Kim, Hee-Joo;Hyun, Yun-Jung;Kim, Young-Ju;Hwang, Sang-Il
    • Journal of Soil and Groundwater Environment
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    • v.16 no.6
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    • pp.113-121
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    • 2011
  • In this study, we suggested the management scheme of analyzing the national and oversea related policy against soil and groundwater contamination by radioactive materials due to nuclear accidents. In Korea, we need to remedy swiftly the contaminated land due to intensive land development demand. So, we need to develop more effective management scheme to recover actively the land contaminated by radioactive materials. We require to improve monitoring network, to expand media-specific monitoring system, to prepare management system for remediation of contaminated land, and to develop flow work for soil and groundwater remediation.

Control of accidental discharge of radioactive materials by filtered containment venting system: A review

  • Bal, Manisha;Jose, Remya Chinnamma;Meikap, B.C.
    • Nuclear Engineering and Technology
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    • v.51 no.4
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    • pp.931-942
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    • 2019
  • Radioactive materials are released from the molten core into the containment at the time of a severe accident in a nuclear power plant (NPP). Filtered containment venting system is a popular and effective safety measure installed to obstruct the uncontrolled escape of radioactive materials due to the over pressurization of the containment. Different designs of filtered containment venting system (FCVS) are available today, each being the result of extensive research and development varying in one way or the other. This paper gives an elaborate description of the different types of FCVS currently being used, the current usage status in over 17 countries and the legislations regarding it. The recent researches being carried out in this field has also been discussed in detail. This present paper focuses on the critical review of existing FCVS, reports the challenges faced by it and highlights the potential developments to overcome the difficulties.

Laser decontamination for radioactive contaminated metal surface: A review

  • Qian Wang;Feisen Wang;Chuang Cai;Hui Chen;Fei Ji;Chen Yong;Dasong Liao
    • Nuclear Engineering and Technology
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    • v.55 no.1
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    • pp.12-24
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    • 2023
  • With the improvement of laser technology, the strategic needs of efficient and precise decontamination of various components in nuclear application units can be fulfilled by laser decontamination. The surface contaminants of nuclear facilities mainly exist both as loose contaminated layer and fixed oxide layer. The types of radionuclides and contamination layer thickness are closely related to the operation status of nuclear facilities, which have an important influence on the laser decontamination process. This study reviewed the mechanism of laser surface treatment and the influence of laser process parameters on the decontamination thickness, decontamination factor, decontamination efficiency and the distribution of aerosol particle. Although multiple studies have been performed on the mechanism of laser processing and laser decontamination process, there are few studies on the microscopic process mechanism of laser decontamination and the influence of laser decontamination on surface properties. In particular, the interaction between laser and radioactive contaminants needs more research in the future.