• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2339-2358
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• 2022

The review discusses various alternative approaches for spent nuclear fuel (SNF) reprocessing in aqueous carbonate media. The main stages, schemes, and methods of the most well-known and well-described processes for reprocessing SNF and some high-level radioactive waste using carbonate systems developed by research groups in Japan, the United States of America, the Republic of Korea, and the Russian Federation described and compared. The main advantages of such methods are outlined compared to the SNF reprocessing in nitric acid media. The levels of development and proximity of the designed processes to the industrial implementation are shown. The main principle achievements, prospects, and routes for the refinement of such methods for the technology of SNF reprocessing and handling of high-level radioactive waste formulated.

• Journal of Positioning, Navigation, and Timing
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• 제9권3호
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• pp.229-236
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• 2020

The trend of water vapor contents in atmosphere is one of key elements for studying climate change. The tropospheric products, i.e., ZTD values achieved through GPS data processing can retrieve the amount of water vapor with higher temporal and spatial resolution than any other instruments. In this study, the tropospheric products of KASINET for a time period from 2001 to 2014 are reprocessed using PPP strategy and the products from the CODE's 2nd reprocessing campaign. For consistency with reprocessing activities of other networks like EPN, the VMF1 mapping function and non-tidal loading effect due to atmospheric pressure are applied in the process. The reprocessing results are investigated through comparing with the CODE's 2nd reprocessing products by including some IGS stations in the process and also calculating weekly coordinate repeatability to see the quality of the processing. After removing outliers based on the variation of averaged formal error, all processed stations have similar variations of formal error about 2 mm which is lower than that of the IGS final product. Comparison results with the CODE's 2nd reprocessing products show that the overall mean difference is found to be -0.28±5.54 mm which is similar level of the previous studies. Finally, the ZTD trends of all KASINET stations are calculated and the averaged trend is achieved as 0.19 mm/yr. However, the trend of each month shows different amounts and directions from -1.26 mm/yr in May to 1.18 mm/yr in August. In conclusion, the reprocessed tropospheric product and applied strategy of this study has enough quality as one of reliable solution for a reference product for Korean Peninsula which is needed to use GPSbased tropospheric product for climate change research.

• 한국정보과학회논문지:데이타베이스
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• 제30권2호
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• pp.184-196
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• 2003

공간 객체를 수정하는 모바일 트랜잭션은 단절 상태에서 지역 데이타를 독립적으로 수정할 수 있는 긴 트랜잭션이다. 모바일 트랜잭션의 수행에 적합하다고 알려진 검증 기반 프로토콜은 데이타 일관성을 유지하기 위하여 충돌된 트랜잭션을 철회시킨다. 그러나 긴 트랜잭션을 철회하면 모든 작업 결과를 취소해야 하기 때문에 철회 방법은 모바일 트랜잭션 수행에 적합하지 않다. 이 논문에서는 충돌된 모바일 트랜잭션을 철회하지 않고 충돌을 해소하기 위하여 재수행 트랜잭션 모델을 제안한다. 그리고 재수행 트랜잭션을 지원하는 트랜잭션 서버를 설계하고 모바일 현장 시스템의 프로토타입을 구현하였다. 재수행 트랜잭션은 외래 충돌 객체를 이용하여 충돌 객체만을 재수정 하는 트랜잭션으로 완료를 요청한 트랜잭션의 충돌에 의해 시작되는 서브 트랜잭션이다. 그리고 재수행 트랜잭션의 기아 문제를 줄이기 위하여 쓰기 집합의 객체들 중 비충돌 객체는 다른 트랜잭션에게 노출시키는 점진적 재수 행 기법을 제시한다.

• 방사성폐기물학회지
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• 제21권3호
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• pp.383-395
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• 2023

Since 1997, the Republic of Korea (ROK) has been developing pyro-processing (Pyro) technology to reduce the disposal burden of high-level radioactive waste by recycling spent nuclear fuel (SNF). Compared to plutonium and uranium extraction process, Korean Pyro technology has relatively excellent proliferation resistance that cannot separate pure plutonium owing to its intrinsic characteristics. Regarding Pyro technology development of ROK, the Bush administration considered that Pyro is not reprocessing under the Global Nuclear Energy Partnership, whereas the Obama administration considered that Pyro is subject to reprocessing. However, the Bush and Obama administrations did not allow ROK to conduct full Pyro activities using SNF, even though ROK had faithfully complied with international nonproliferation obligations. This is because the US nuclear nonproliferation policy to prevent the spread of sensitive technologies, such as enrichment and reprocessing, has a strong effect on ROK, unlike Japan, on a bilateral level beyond the NPT regime for non-proliferation of nuclear weapons.

• Journal of Korean Biological Nursing Science
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• 제18권4호
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• pp.288-295
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• 2016

Background: This study was conducted in order to survey the current state of cleaning, disinfection, rinsing, drying, and storage of gastrointestinal endoscopes. Methods: Eighty hospitals were selected through convenient sampling. Self-reported questionnaire was distributed from September 14 to October 10 in 2015. Results: The response rate was 67.5% (54/80). In 88.9% of the hospitals, reprocessing was performed in a cleaning space separated from the laboratory and 88.9% used an enzymatic cleaner. Disinfectants used were ortho-phthalaldehyde in 63.0%, and paracetic acid in 33.3%. Eighty seven percent of the hospitals used test strips in order to test the effective concentration of disinfectant and in 61.1%, drying was done through passing air and over 70% alcohol. Microbial culture for the quality control of gastrointestinal endoscopes was performed in 77.8%. In the comparison of the adequacy of gastrointestinal endoscope reprocessing, it was observed that gastrointestinal endoscopes were reprocessed more adequately in larger and tertiary care hospitals. Conclusion: Gastrointestinal endoscopes were reprocessed in similar manners, but there were differences in the detailed process. It is still necessary to segment reprocessing into stages, to prepare standardized guidelines, and to monitor compliance with the guidelines.

• Nuclear Engineering and Technology
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• 제51권7호
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• pp.1799-1804
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• 2019

The concept of a new method, the CARBEX (CARBonate EXtraction) process, was proposed for reprocessing of spent uranium oxide fuel. The proposed process is based on use of water solutions of $Na_2CO_3$ or $(NH_4)_2CO_3$ and solvent extraction (SE) by the quaternary ammonium compounds for selective recovery and purification of U from the fission products (FPs). Applying of SE allows to reach high degree of purification of U from FPs. Carrying out the processes in poorly aggressive alkaline carbonate media leads to increasing safety of SNF's reprocessing and better selectivity of separation of lanthanides and actinides. Moreover carbonate reprocessing media allows to carry out a recycling and regeneration of reagents. We have been done laboratory scale experiments on the extraction components of simulated voloxidated spent fuel in the solutions of NaOH or $Na_2CO_3-H_2O_2$ and recovery of U from carbonate solutions by SE method using carbonate of methyltrioctylammonium in toluene. It was shown that the purification factors of U from impurities of simulated FPs reached values $10^3-10^5$. The received results support our opinion that CARBEX after the further development can become more safe, simple and profitable method of spent fuel reprocessing.

• 대한불안의학회지
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• 제5권1호
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• pp.42-47
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• 2009

Recently, Eye Movement Desensitization and Reprocessing (EMDR) was given the status of an approved form of psychotherapy for the treatment of post-traumatic stress disorder. However, its effectiveness in the treatment of other anxiety disorders such as phobia is yet to be determined given that controlled studies have provided mixed results. This report summarizes the case of a child with a specific phobia (i.e. nighttime fear) which was successfully treated with two sessions of EMDR. This result suggests the further and thorough evaluation of this technique for use in childhood phobic disorders.

• Elastomers and Composites
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• 제57권2호
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• pp.55-61
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• 2022

In this work, we report a highly deformable covalent adaptable-liquid crystal elastomer (CA-LCE) comprising dynamic thiourea bonds that enable macromolecular network rearrangement at elevated temperatures. The exchange of chain network is verified through stress-relaxation analyses and follows Arrhenius-type behavior. The unique capability of rearranging the chain network in the CA-LCE provides useful properties, such as welding, melt reprocessing, and shape reprogramming, that cannot be achieved by the conventional LCE comprising permanent crosslinks. Reversible actuation is further demonstrated by reprogramming the polydomain CA-LCE into a monodomain via mechanical stretching at elevated temperatures.

• Journal of Radiation Protection and Research
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• 제41권2호
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• pp.117-121
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• 2016

Background: Definition and grouping of initiating events (IEs) are important basics for probabilistic safety assessment (PSA). An IE in a spent fuel reprocessing plant (SFRP) is an event that probably leads to the release of dangerous material to jeopardize workers, public and environment. The main difference between SFRPs and nuclear power plants (NPPs) is that hazard materials spread diffusely in a SFRP and radioactive material is just one kind of hazard material. Materials and Methods: Since the research on IEs for NPPs is in-depth around the world, there are several general methods to identify IEs: reference of lists in existence, review of experience feedback, qualitative analysis method, and deductive analysis method. While failure mode and effect analysis (FMEA) is an important qualitative analysis method, master logic diagram (MLD) method is the deductive analysis method. IE identification in SFRPs should be consulted with the experience of NPPs, however the differences between SFRPs and NPPs should be considered seriously. Results and Discussion: The plutonium uranium reduction extraction (Purex) process is adopted by the technics in a model reprocessing plant. The first extraction cycle (FEC) is the pivotal process in the Purex process. Whether the FEC can function safely and steadily would directly influence the production process of the whole plant-production quality. Important facilities of the FEC are installed in the equipment cells (ECs). In this work, IEs in the FEC process were identified and categorized by FMEA and MLD two methods, based on the fact that ECs are containments in the plant. Conclusion: The results show that only two ECs in the FEC do not need to be concerned particularly with safety problems, and criticality, fire and red oil explosion are IEs which should be emphatically analyzed. The results are accordant with the references.

• Journal of Radiation Protection and Research
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• 제25권2호
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• pp.89-96
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• 2000

원자력 정책에서 안전성과 운영실적, 환경보전, 경제성 등은 매우 중요한 인자이다. 핵주기의 선택은 에너지정책, 연료의 다양성, 공급의 안정과 관련된 모든 사회적, 환경적 영향에 있어 매우 중요하다. 특히, 원전의 고준위 방사성폐기물인 사용후 핵연료 관리는 높은 방사선준위 뿐만 아니라 장기적인 관리기간이 소요되는 어려운 사업이다. 본 연구는 사용후 핵연료 관리방안인 재처리와 직접 처분의 비용분석, 안전성, 대국민 용인 측면을 살펴보았다. 직접 처분이 재처리에 비해 약 7%정도의 경제성이 있고, 직접 처분의 사용후 핵연료는 재처리폐기물보다 높은 위험도를 갖는다. 대국민 용인측면에서는 두 가지 처리방법 모두 찬성하지 않는다. 결론적으로, 사용후 핵연료관리는 모든 사회/환경적 영향과 경제성을 고려한 핵주기 정책과 병행하여 지속적인 기술개발을 통한 안전성확보가 필요하다.