• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.2
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• pp.189-200
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• 2016

The Republic of Tajikistan has ten former uranium mining sites. The total volume of all tailings is approximately 55 million tonnes, and the covered area is more than 200 hectares. The safe management of legacy uranium mining and tailing sites has become an issue of concern. Depending on the performance requirements and site-specific conditions (location in an arid, semiarid or humid region), a cover system for uranium tailings sites could be constructed using several material layers using both natural and man-made materials. The purpose of this study is to find a feasible cost-effective cover system design for the Degmay uranium tailings site which could provide a long period (100 years) of protection. The HELP computer code was used in the evaluation of potential Degmay cover system designs. As a result of this study, a cover system with 70 cm thick percolation layer, 30 cm thick drainage layer, geomembrane liner and 60 cm thick barrier soil layer is recommended because it minimizes cover thickness and would be the most cost-effective design.

• Korean Journal of Optics and Photonics
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• v.28 no.3
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• pp.108-115
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• 2017

We report the assembly procedure and performance evaluation of a visible and near-infrared spectrometer in the wavelength region of 400-900 nm, which is later to be combined with fore-optics (a telescope) to form a f/2.5 imaging spectrometer with a field of view of ${\pm}7.68^{\circ}$. The detector at the final image plane is a $640{\times}480$ charge-coupled device with a $24{\mu}m$ pixel size. The spectrometer is in an Offner relay configuration consisting of two concentric, spherical mirrors, the secondary of which is replaced by a convex grating mirror. A double-pass test method with an interferometer is often applied in the assembly process of precision optics, but was excluded from our study due to a large residual wavefront error (WFE) in optical design of 210 nm ($0.35{\lambda}$ at 600 nm) root-mean-square (RMS). This results in a single-path test method with a Shack-Hartmann sensor. The final assembly was tested to have a RMS WFE increase of less than 90 nm over the entire field of view, a keystone of 0.08 pixels, a smile of 1.13 pixels and a spectral resolution of 4.32 nm. During the procedure, we confirmed the validity of using a Shack-Hartmann wavefront sensor to monitor alignment in the assembly of an Offner-like spectrometer.

• Proceedings of KOSOMES biannual meeting
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• 2007.05a
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• pp.187-194
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• 2007

In order to control and manage oil-tanker scrapped materials and wastes properly, the actual conditions and global trends of the treatment and the management of ship scrapped wastes were surveyed and some amendments to marine pollution prevention law of Korea were proposed. Global annual volume of scrapped ships was estimated to be about 22 million DWT and most of them were scrapped in 4 major ship scrap countries such as Bangladesh, China. India and Pakistan and in minor ship scrap countries such as Turkey, the Philippines, Indonesia and Vietnam. The industry of ship scrap has been mainly developed in developing countries or undeveloped countries rather than in advanced countries. Most of scrapped ships were found to be small or medium size below 1,000 GRT In Jellanam-Do and Jeju-Do of Korea. Most of ship scrap enterprise and all enterprises of collection, transfer, treatment and disposal for ship scrapped materials and wastes were shown to be small sized in Korea. The regulations and/or rules which shall prohibit or limit trans-boundary movement of overage oil-tankers for scrap from Korea to developing or undeveloped countries, and vice versa should be Included in marine pollution prevention law of Korea. the criteria of manpower and facilities for enterprise of ship scrap, and for enterprises of collection, transfer, treatment and disposal of ship scrapped materials and wastes should be stipulated in marine pollution prevention law of Korea. It is desirable to introduce the system or concept of recycle or reuse of ship scrapped materials and wastes on producer's responsibility into marine pollution prevention law of Korea.