• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.343-356
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• 2016

The Korea Radioactive Waste Agency (KORAD) has developed a dual-purpose metal cask for the dry storage of spent nuclear fuel that has been generated by domestic light-water reactors. The metal cask was designed in compliance with international and domestic technology standards, and safety was the most important consideration in developing the design. It was designed to maintain its integrity for 50 years in terms of major safety factors. The metal cask ensures the minimization of waste generated by maintenance activities during the storage period as well as the safe management of the waste. An activation evaluation of the main body, which includes internal and external components of metal casks whose design lifetime has expired, provides quantitative data on their radioactive inventory. The radioactive inventory of the main body and the components of the metal cask were calculated by applying the MCNP5 ORIGEN-2 evaluation system and by considering each component's chemical composition, neutron flux distribution, and reaction rate, as well as the duration of neutron irradiation during the storage period. The evaluation results revealed that 10 years after the end of the cask's design life, $^{60}Co$ had greater radioactivity than other nuclides among the metal materials. In the case of the neutron shield, nuclides that emit high-energy gamma rays such as $^{28}Al$ and $^{24}Na$ had greater radioactivity immediately after the design lifetime. However, their radioactivity level became negligible after six months due to their short half-life. The surface exposure dose rates of the canister and the main body of the metal cask from which the spent nuclear fuel had been removed with expiration of the design lifetime were determined to be at very low levels, and the radiation exposure doses to which radiation workers were subjected during the decommissioning process appeared to be at insignificant levels. The evaluations of this study strongly suggest that the nuclide inventory of a spent nuclear fuel metal cask can be utilized as basic data when decommissioning of a metal cask is planned, for example, for the development of a decommissioning plan, the determination of a decommissioning method, the estimation of radiation exposure to workers engaged in decommissioning operations, the management/reuse of radioactive wastes, etc.

• Journal of Science Education
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• v.33 no.1
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• pp.111-121
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• 2009

The purpose of this research is to survey elementary pre-service teachers' in understand the legal Units, focusing on seven basic unit such a 'm', 'm2', 'L', 'kg', 'K', 'cd', 's'. This study specifically investigates whether the students understand the legal units. The subjects were 1096 students from the University of Education in Jinju, Gyeongnam. Data was collected through a questionnaire which was designed by this research and checked by authority, and the frequency and percentage of responses to each question were obtained and analysed. The survey was the legal units on interesting, using the experience of confusing and understanding of elementary pre-service teachers. The Korea Government is regulating using traditional measures such as 'pyeong' or 'don' in commercial transactions change to adopt the metric system for as a subsidiary the first of July, 2007. The interesting of the legal units dose not exceed a positive answer to the question 52.1%. Their were answered that the experience of the confused of 60.1% in the life. How to do efforts for the settle down of the legal units that answered broadcasting>in class>a campaign>study and training by an academic year in oder. Findings show regardless of academic year, gender and from the department of liberal arts or the science department all the students knew very well that 'm' '$m^2$', 'L', 'kg' are included in the legal units, compared to the others low percentage of 'K', 'cd' and 's' the legal units. In case of time(s), women has correct answered 2.7 times than man. In case of academic year, except for the third-year students was not to exceed 50%. In case of from the department of liberal arts or the science department contrary to one's expectations increase of 50% or more correct answer while half the students scored in science. The elementary pre-service teachers are seems to thinking separate the legal units with their in university life. Also elementary pre-service teachers are the lack of interest on society. Their should be for settle down of the legal units through learning to class in university, newspapers, strengthen publicity activities of broadcast media's further more by maintenance efforts of the government.