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        검색결과 1,806

        81.
        2023.05 구독 인증기관·개인회원 무료
        The intermediate level spent resins waste generated from water purification for the the moderator and primary heat transport system during operaioin of heavy water reactor (HWR). Especially, moderator resins contain high level activity largely because of their C-14 content. So spent resins are considered as a problematirc solid waste and require special treatment to meet the waste acceptance criteria for a disposal site. Various methods have been studied for the treatment of spent resins which include thermal, destructive, and stripping methods. In the case of solidification methods, cement, bitument or organic polymers were suggested. In the 1990s, acid stripping using nitric acid and thermal treatment methods were actively investigated in Canada to remove C-14 nuclide from waste resin. In Japan, thermal distructive method was studied in the 1990s. Since 2005, KAERI developed acid stripping method using phosphate salt. However, acid stripping method are not suitable due to large amounts of 2nd waste containing acid solution with various nuclides. To solve this probelm, KAERI has been suggested the microwave treatment method for C-14 selective removal from waste resin in the 2010s. Pilot scale demonstration tests using radioactive waste resin generated from Wolsung unit 1 and unit 2 were successfully conducted and 95% of C-14 was selectively removed from the radioactive waste resin. In recent years, price of C-14 source is dramatically increased due to market growth of C-14 utilization and exclusive supply chain depending on China and Russia. High purity of C-14 were captured in HWR waste resin. Interest of C-14 recovery research from HWR waste resin is currently increased in Canada. In this study, microwave method is suggested to treat HWR waste resin with C-14 recovery process. Additionally, status of waste resin management and research trends of HWR waste resin treatment are introduced.
        82.
        2023.05 구독 인증기관·개인회원 무료
        On March 11 2011, Fukushima Daiichi nuclear power plant site was attacked by a huge tsunami caused by Tohoku Pacific Ocean earthquake. Nuclear fuels of unit 1, 2, and 3 of Fukushima Daiichi nuclear power plant was melted down by the disaster. After the accident, Japan’s government has announced “Mid-and-Long-Term Roadmap towards the decommissioning of TEPCO’s Fukushima Daiichi Nuclear Power Station Units 1-4”. The topics of roadmap is made of measures to deal with contaminated water, removal of fuel rod assemblies from spent fuel pools, retrieval of fuel debris, measures to deal with waste materials, and other operations. To support the activity of the roadmap, various facilities about decommissioning have been established and operated on inside or outside of Fukushima Daiichi nuclear power plant site. Representatively, Collaborative Laboratories for Advanced Decommissioning Science which conducts R&D decommissioning, Naraha Remote Technology Development Center which develops remotes robots and VR (Virtual reality), Okuma Analysis and Research Center which performs radiochemical analyses for radioactive waste, and Fukushima Environmental Safety Center which conducts environmental dynamics and radiation monitoring.
        83.
        2023.05 구독 인증기관·개인회원 무료
        Wolsong Unit 1 is about 679 MW Pressurized Heavy Water Reactor (PHWR). Canada AECL was responsible for Nuclear Steam Supply System (NSSS) design and supply. Wolsong Unit 1 was operated from 1983 to 2019. Currently, Wolsong Unit 1 is under safety management after permanent shutdown. Wolsong unit 1, a heavy water reactor, has the following characteristics. • Unlike Light Water Reactor, vertical reactors, Heavy Water Reactor is installed horizontally. • The internal structure of the reactor is more complex than that of a light water reactor (380 pressure tubes in reactor as called Calandria) • The Calandria Vault, a large concrete structure filled with light water, is located outside of Calandria In the case of the decommissioning plan of PHWR in Canada, they have adopted a deferred decommissioning strategy that decommissioning begins after permanent shutdown and long-term safety management (30 to 40 years). So, Decommissioning of PHWR in Canada is expected to start in the 2050s. Nuclear Safety Act stipulates that if a commercial nuclear power plant is permanently suspended, the utility must submit a Final Decommissioning Plan (FDP) within 5 years. So, KHNP, the utility, is developing the FDP for Wolsong Unit 1 and have a plan to submit it to the government by the end of 2024. And then licensing review is expected to take at least two years. The key milestone for decommissioning project has a plan to start decommissioning in 2027 and complete it by 2034, but this is flexible depending of the government’s approval for decommissioning and the completion of prerequisites such as spent fuel transfer, etc. KHNP has prepared a strategy and system consisting of three areas such as R&D, Engineering and licensing document development to prepare the final decommissioning plan for Wolsong Unit 1. The promotion system for the preparation of the FDP for Wolsong Unit 1 is consisted of Engineering (HAS Characterization, Process/Work Package/Cost Estimation, Dismantling Safety Evaluation, Radiological Environmental Report, Radioactive Waste Treatment and Facility Construction), R&D (COG cooperation, KHNP R&D Results), Kori unit 1 lessons learned, etc. KHNP have the plan that the FDP Draft development by the end of 2023, reflecting engineering services results, R&D results, COG technical cooperation results and lessoned learned on Kori Unit 1. After collecting opinions from residents through a public hearing, the FDP will be submitted to the government by the end of 2024. It is expected that there will be many difficulties in the development process as it is the world’s first FDP development for the commercial Pressurized Heavy Water Reactors.
        84.
        2023.05 구독 인증기관·개인회원 무료
        Kori Unit 1 is about 600MW Pressurized Light Water Reactor as WH type. KHNP got an approval for construction and operation of Kori unit 1 on May 31, 1972 and started commercial operation from Apr. 29, 1987. And then, it was decided to permanently suspend it on Jun. 18, 2017 after 40 years of commercial operation. The Nuclear Safety Act stipulates that if a commercial nuclear power plant is permanently suspended, the utility must submit a Final Decommissioning Plan (FDP) within 5 years. So, KHNP, the utility, developed a FDP for Kori Unit 1 and submitted it to the government in May 2021. In South Korea, the FDP is to be prepared in accordance with the relevant notices and consists of 11 major chapters such as (1) Decommissioning Plan Overview, (2) Project management, (3) Status of Site and Environmental, (4) Decommissioning Strategies and Method, (5) Ease of Decom. Design characteristic, (6) Safety Analysis, (7) Radiation Protection, (8) Decontamination and Dismantling, (9) Radioactive Waste Management, (10) Environmental Impact Analysis, (11) Fire Protection and (12, 13) Etc., References and Glossary. KHNP has prepared a strategy and system consisting of three areas such as R&D, Engineering and licensing document development to prepare the final decommissioning plan for Kori Unit 1. The promotion system for the preparation of the FDP for Kori Unit 1 is composed of Engineering (HAS Characterization, Dismantling Safety Evaluation, Radiological Environmental Report, Radioactive Waste Treatment and Facility Construction), R&D(KHNP R&D Results such as Process/Work Package /Cost Estimation, Safety Analysis, Contamination and Exposure, Guide for Detailed Characteristic, Site Safety Analysis, RV & RVI Dismantling Process, etc.), Overseas case lessons learned(Taiwan unit 1 NPP FDP and Spain Zorita NPP FDP analysis) and Development of Licensing Document. KHNP completed the initial completion of the Final Decommissioning Plan for Kori Unit 1 in March 2020 and carried out collecting residents’ opinions through public hearings. And then, KHNP supplemented the results of the residents’ opinions and applied for license to the Nuclear Safety and Security Commission in May, 2021. Now, KHNP are responding to the FDP licensing review.
        85.
        2023.05 구독 인증기관·개인회원 무료
        Hanford site has been operated since 1943 to produce the plutonium for nuclear weapons. Significant amount of radioactive wastes was generated by the nuclear weapons production process. The radioactive wastes are stored in 177 aged underground tanks. Due to the risk of leakage into the air and the Columbia River, the US DOE and EPA, and Washington State Department of Ecology organized the Tri-Party Agreement (TPA) to clean-up the Hanford site in 1989. The LAW (low-activity waste) vitrification facility named WTP (Waste Treatment Plant) is plan to vitrify about 212 million liters of radioactive waste. The US DOE announced that the world’s largest melter to vitrify the LAW was heated up on October 8, 2022.
        86.
        2023.05 구독 인증기관·개인회원 무료
        Japan’s government has announced plan to release the contaminated water stored from the tanks of the Fukushima Daiichi nuclear power plant site into the sea in June. The contaminated water is treated by SARRY (Cesium removal facility) and ALPS (advanced liquid processing system) to remove 62 radionuclide containing Cesium, Strontium, Iodine, and so on using filtration, precipitation (or coprecipitation) and adsorption for other nuclides (except for H-3 and C-14). The total amount of the contaminated water stored at tanks is 1,328,508 m3 (as of March 23, 2023). Currently, three ALPS systems which are existing ALPS, improved ALPS, high performance ALPS have been operated to meet the regulatory standard for release to the sea. According to the release plan, they have announced that 30 nuclides and H-3 concentration of the contaminated water will be measured and assessed before/after the discharge of the contaminated water into the sea. Before the release, the contaminated water is re-treated by reverse osmosis membrane facility and additional ALPS. And then, the water will be diluted with seawater more than 100 times. The diluted water will then move through an undersea tunnel and be released about 1 kilometer off the coast.
        87.
        2023.05 구독 인증기관·개인회원 무료
        CANDU Spent Fuel (CSF) dry storage system, SILO, has been operated from 1992 at Wolsung under 50 year operating license. As of 2023, this system has been operated for over 30 years and its licensed remaining operation time is less than 20 years. When it faces the final stage of operation, it has only two options; moving to a centralized away-from-reactor storage or extending its license atreactor. These two options have an inevitable common duty of confirming the CSF integrity by a “demonstration test”. Since the degradation of CSF and structural materials in the SILO are critically dependent on temperature, two important goals of the ‘DEMO test’ were set as follows. 1. Design of ‘DEMO SILO’: Development of internal monitoring technology by transforming SILO design. 2. Accurate measurement and evaluation of the three-dimensional temperature distribution in the ‘DEMO SILO’ Based on operating real commercial SILO dimension, a conceptual “DEMO SILO” design has been developed from 2022. Because, unlike with commercial Silo, ‘Demo Silo’ must be disassembled and assembled, and have penetration holes. Safety evaluation technologies like structural, thermal and radiation protection analysis also have been developed with design work. ‘Demo SILO’ should evaluate an accurate 3D temperature distribution with minimal number of thermocouples and penetration holes to avoid disruption of internal flow and temperature distribution. For this reason, a ‘Best Estimate Thermal-Hydraulics evaluation system for SILO’ is under development and it will be essential for ensuring temperature prediction accuracy. Construction of a full-scale test apparatus to validate this technology will begin in 2024. In order to supply power to many heaters and monitor temperature gradient inside of this apparatus, it has modular design concept by dividing its whole body to axial 9 sub-bodies which looks like a donut containing a basket at center position.
        88.
        2023.05 구독 인증기관·개인회원 무료
        Given the limited terrestrial reserves of uranium (about 4.6 million tons), exploring alternative resources is essential to ensure the long-term supply and sustainability of nuclear energy. Uranium extraction from seawater (UES) is a potential solution to this issue since the amount of uranium dissolved in seawater (about 4.5 billion tons) is approximately 1000 times that of terrestrial reserves. However, the ultra-low concentration of uranium in seawater (about 3.3 ppb) makes it a challenging task to make UES economically feasible. This paper provides an overview of the current status of UES technology, which has evolved over the past seven decades. Starting from inorganic adsorbents such as hydrous titanium oxide in the 1960s, amidoxime-based fibrous adsorbents gained the most attention until the early 2010s due to their ease of deployment in actual seawater conditions and high affinity for uranium. Nowadays, research on organic adsorbents with microstructures is prevailing due to their ability to easily control surface area and compositions. In addition, this study identifies the key issues that need to be addressed to make UES technology economically viable.
        89.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 기업뿐만 아니라 국가 차원의 지속가능성을 개념으로 하는 일본의 ESG 채권에 관한 제도 및 운영사항을 살펴보고 한국 지자체에서 발행하는 ESG 채권 운영과 제도 활성화에 관한 시사점을 얻는 것을 연구목적으로 한다. 향후 지자체에 의한 ESG 채권 발행은 시장 규모가 확대됨에 따라 용도와 계획이 증가될 것으로 예상된다. 이러한 상황에서 ESG 채권 시장의 건전한 발전을 위해서는 환경 및 사회 개선 효과의 신뢰성을 확보하고 발행자의 비용 및 행정 부담을 줄여야 할 것이다. 본 연구는 ESG 투자의 활성화 를 위한 제도 설계와 정책 수립, 기관의 설립, ESG 투자 방법, 임팩트 평가 기법을 확립하고 보급해야 함을 강조한다. 또한 정부와 지자체의 ESG 투자와 관련 이해관계자 간 연결 강화와 커뮤니티 형성 촉진 노력을 제언한다.
        6,100원
        90.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Non-discrimination is a fundamental principle of the World Trade Organization (WTO), which promotes global trade with the goal of eradicating hunger, reducing poverty, and ensuring global prosperity. According to the WTO rules, members are required to give other members most-favoured-nation and national treatment. Due to the military conflict between the Russian Federation and Ukraine, the United States, European Union, and several other member countries suspended most-favoured-nation treatment for Russian goods in mid-March 2022. This study examines the principle of non-discrimination under the WTO provisions, identifies relevant exceptions, analyses the Russia-Traffic in Transit case, and evaluates the appropriateness of the above actions by the US and others. Finally, this paper concludes that the US and its allies failed to present concrete evidence demonstrating a direct and causal relationship between the military situation in Ukraine and their own essential interests under Article XXI of GATT 1994.
        4,300원
        91.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 본 연구는 작업치료사가 참여한 지역사회 통합돌봄 서비스 중 가정환경수정 대상자의 일상생활활동에 영향을 주는 요인을 분석하여 향후 가정환경수정 중재에 있어 필요한 요인을 제시하고자 한다. 연구방법 : 본 연구는 광주광역시 서구 지역사회 통합돌봄 서비스의 필요도 조사 데이터를 활용한 이차자료 분석연구이다. 대상자는 2020년 상반기부터 2022년 상반기까지 중복으로 신청했던 16,388명이며, 이 중 가정환경수정 이용한 1,075명 의 데이터를 추출하여 분석하였다. 가정환경수정 대상자의 일상생활활동과 주거환경, 주관적 건강상태, 인지기능에 대한 상관관계를 분석하기 위해 피어슨 상관분석을 실시하였다. 가정환경수정 대상자의 주거환경, 주관적 건강상태, 인지기능이 일상생활활동에 영향을 주고 있는지 분석하기 위해 다중회귀분석을 실시하였다. 또한, 가정환경수정 대상자의 개선이 필요 한 주거환경 현황을 알아보기 위해 기술통계 및 그래프를 활용하였다. 결과 : 가정환경수정 대상자의 일상생활활동은 조명, 계단, 문턱, 온수, 주관적 건강상태, 인지기능이 좋을수록 일상생활 활동의 독립성이 높아진다고 볼 수 있다. 또한 대상자의 고령, 여자보다는 남자일 때, 높은 사회보장수급권, 열악한 바닥 과 벽지, 이동이 불편한 계단과 문턱, 낮은 주관적 건강상태와 인지기능이 일상생활에 부정적인 영향을 주는 것으로 분석 되었다. 가정환경수정 대상자의 가정환경 개선 욕구에서는 안전 손잡이, 욕조, 바닥과 벽지 순으로 조사되었다. 결론 : 노인의 맞춤형 가정환경수정을 위해서는 신체적 기능과 인지적 기능을 고려하여 바닥과 벽지, 계단, 문턱 등 환경 적 측면에 대한 분석이 필요하며, 이를 수행할 수 있는 작업치료사가 적절하게 배치될 수 있는 정책적 지원이 필요하다.
        4,300원
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