• Nuclear Engineering and Technology
• /
• v.55 no.6
• /
• pp.2206-2214
• /
• 2023

The existing wet reconversion processes for the recovery of scraps generated in manufacturing of nuclear fuel are complex and require several unit operation steps. In this study, it is attempted to simplify the recovery process of high-quality fuel-grade UO₂ powder. A novel wet reconversion process for uranyl nitrate hexahydrate solution is suggested by using a newly developed pulsed fluidized bed reactor, and the resultant chemical characteristics are evaluated for the intermediate ammonium uranate hydrate product and subsequently converted UO₂ powder, as well as the compliance with nuclear fuel specifications and advantages over existing wet processes. The UO₂ powder obtained by the suggested process improved fuel pellet properties compared to those derived from the existing wet conversion processes. Powder performance tests revealed that the produced UO₂ powder satisfies all specifications required for fuel pellets, including the sintered density, increase in re-sintered density, and grain size. Therefore, the processes described herein can aid realizing a simplified manufacturing process for nuclear-grade UO₂ powders that can be used for nuclear power generation.

• Journal of Forest and Environmental Science
• /
• v.32 no.1
• /
• pp.55-67
• /
• 2016

This paper investigated policies that drive the sustainable management of Ivorian forest which disappear at an annual rate of 250000 hectares. Based on an inter-temporal model for optimum allocation of forest land to three competing uses, the article found that sustainability depends on the incentive structure, of which forest taxes and fees are a key, though obviously not the sole, component. The study proposed to increase the area fee level by accounting for environmental externalities generated by forest harvesters and farmers. The paper showed that the area fee is a decreasing function of the forest natural rate of regeneration and the reconversion rate of agricultural surfaces. Finally, at the given forest natural rate of regeneration and the reconversion rate of agricultural surfaces, the model argued that the area fee need to be progressive (arithmetic progression) in the context of ecological equilibrium break while it should remain constant in normal situation.

• Journal of the Korean association of regional geographers
• /
• v.8 no.4
• /
• pp.415-429
• /
• 2002

The end of cold war and the trend of the detente brought about many changes in the military security policy and in the munitions industry of the West-Europe : reduction of the defence budget, diminution of the military power force and armaments, decrease of the exportation and the domestic demand of ordnance, and augmentation of discharged laborers. This mutation caused the munitions industry and the war industrials regions to a crisis. The munition industrials enterprises which was confronted a crisis searched for diverse strategies like an reconversion to the civil products, an internal diversification and an external growth. And the European Union, the national government, and local or regional self-government implemented policies for diversification of regional economic with an reconversion in order to minimize the effect of the regional economic and society from the crisis of the munition industry.

• International Journal of Highway Engineering
• /
• v.17 no.3
• /
• pp.1-12
• /
• 2015

PURPOSES : This paper presents a description of the current issues facing road managers regarding the surface-type conversion of low-volume roads for cost savings. METHODS: The paper reviews previous works conducted toward this end, acknowledges gaps in the current research, and lays out what information is needed for further studies. RESULTS : If the cost to maintain an unsurfaced road is less than the cost of maintaining a surfaced road, then there is potential for cost savings for the management agency. However, the problem is bigger than simply maintaining the roads that already exist. If unsurfaced roads prove to be more economical than surfaced roads, then the cost to convert from a surfaced to an unsurfaced roadway, and vice versa, when necessary, must also be examined. CONCLUSIONS : No other studies have addressed the un-surfacing of a road for cost savings, and it is therefore unknown whether substantial savings can be realistically obtained by converting from a surfaced to an unsurfaced road. To determine whether a conversion policy would be a viable option, additional data and research are needed.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.732-741
• /
• 2008

After freight train line opening between Munsan of South Korea and Bongdong of North Korea last December 2007, people's expectation and interest about trans North-South and continental railways have been increasing. However, the commercial traffic of freight by train has not been increased as much as we expected in the mean time road traffic is more increased. This study examined the Kaesong industrial complex which has a high rail accessibility. Especially, we interviewed the owners of enterprises in Kaesong to integrate their opinions for deriving the problems and improving the business conditions. Also, this study embodied the methods for improving rail freight traffic between North and South Korea. Based on this study, we expect more research will carry out on this field to reform the operation system of trans Korea railways by Kaesong industrial complex development project and the commercial reconversion from road to rail.

• Korean Journal of Materials Research
• /
• v.10 no.2
• /
• pp.166-170
• /
• 2000

Nuclear fuel $UO_{2+x}$ power was produced from concentrated $UF_6$ by the DCP(Dry Conversion Process). The characterstics of $UO_{2+x}$ powder, prepared with respect to steam flowing conditions and temperature variations in a rotary kiln reactor, have been investigated with a uranium analyzer, water vapor measurement, and SEM. Fluorine content of the powder could be reduced to 8ppm. The moisture content was found to be optimized.

• Korean Institute of Interior Design Journal
• /
• v.16 no.6
• /
• pp.36-46
• /
• 2007

Regeneration of old buildings is one of the most imperative responses to the 21th century issue of sustainable urban architectural environment. In particular, creative circulation of generation which conversion means highlights the conversion as a new design method. In this study, by examining buildings built over the last decade, the mutual relationship between old elements of existing buildings and new elements of newly required functions was analyzed and types of relationships such as 'alien insertion', 'mediate intervention', 'endogenous expansional enveloping', 'contrastive confliction' and 'over-layering' were defined. In addition, design strategies including the paradoxical curio, fore-grounding and unification were derived from each relationship. Finally, according to the relation type and design strategy, this study suggests several features of conversion design; (1) maximization of symbolism using unfamiliarities - emphasizing futuristic or contextual symbol with intentional contrasts by preserving the work or using contemporary addition; (2) time confusion using neutral space - meeting the need by harmonizing and cooperating existing elements and new elements; (3) mutual emphasizing by individualization - revealing differences between old and new for an aesthetical tension; (4) synchronism by constructional combination - making the one unity of different layers; (5) expansion by enveloping - experience of visual reverse and creation of extra space by roofing above building groups. The reconversion should be continuously researched in the future since conversion is a sustainable design method for the future of architecture.

• Nuclear Engineering and Technology
• /
• v.49 no.8
• /
• pp.1711-1716
• /
• 2017

Uranium tetrafluoride ($UF_4$) is the most used nuclear material for producing metallic uranium by reduction with Ca or Mg. Metallic uranium is a raw material for the manufacture of uranium silicide, $U_3Si_2$, which is the most suitable uranium compound for use as nuclear fuel for research reactors. By contrast, ammonium uranyl carbonate is a traditional uranium compound used for manufacturing uranium dioxide $UO_2$ fuel for nuclear power reactors or $U_3O_8-Al$ dispersion fuel for nuclear research reactors. This work describes a procedure for recovering uranium and ammonium fluoride ($NH_4F$) from a liquid residue generated during the production routine of ammonium uranyl carbonate, ending with $UF_4$ as a final product. The residue, consisting of a solution containing high concentrations of ammonium ($NH_4^+$), fluoride ($F^-$), and carbonate ($CO_3^{2-}$), has significant concentrations of uranium as $UO_2^{2+}$. From this residue, the proposed procedure consists of precipitating ammonium peroxide fluorouranate (APOFU) and $NH_4F$, while recovering the major part of uranium. Further, the remaining solution is concentrated by heating, and ammonium bifluoride ($NH_4HF_2$) is precipitated. As a final step, $NH_4HF_2$ is added to $UO_2$, inducing fluoridation and decomposition, resulting in $UF_4$ with adequate properties for metallic uranium manufacture.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.7 no.1
• /
• pp.113-123
• /
• 2012

This study aims at identifying whether graduate school of Entrepreneurship is proposed as an alternative for institution enhancing the expertise of entrepreneurship education which is demanded these days and also examining which forms of graduate school of Entrepreneurship is needed between special graduate school of Entrepreneurship and professional graduate school of Entrepreneurship. Three researches are made by this study. First of all, status of special graduate schools of Entrepreneurship and advanced studies are researched and secondly, educational performance and operational performance of them are researched and how they secure the prestige as a professional institution for educating Entrepreneurship has been analyzed. Finally, what needs of switching over from special graduate school of Entrepreneurship to professional graduate school of Entrepreneurship has been rveyed As a result, graduate school of Entrepreneurship has been established at five rovince in Korea. Doctoral course of Entrepreneurship has been opened independently in U. S. A. And also high performance of promoting Entrepreneur and consultant for Entrepreneur has been researched. Level of satisfaction on education program and faculties has been surveyed highly. High demand for reconversion to professional graduate school of Entrepreneurship and doctoral course of Entrepreneurship has been investigated.

• Asian Journal of Turfgrass Science
• /
• v.23 no.1
• /
• pp.123-132
• /
• 2009

This study was designed to investigate the effect of the late fall fertilization applied with methyl urea(MU), compound chemical fertilizer(CF), humate(HM), and organic compost fertilizer(NS) on spring greenup of creeping bentgrass at following year. The plots were treated with various snow cover periods before transforming to ski slopes from golf holes during 2007 fall to 2008 spring. The highest visual quality and greenup rate were shown on MU or HM applications at 10 days before snow cover treatment. The CF treatment which had a highest phosphorus rate was most effective with a 13 cm of root length at the reconversion date to golf hole from ski slope of the following spring. However, the application of CF followed by immediate snow cover showed the worst results on visual quality and green color caused by a leaf burning damage from the residual effect of CF. At least 10 days were required to avoid phytotoxicant from undissolved granular of CF before snow cover practise. The application of NS showed the highest result on leaf dry weight at no snow cover plot in next spring, but not on green color and visual quality. Therefore, the proper interval period of snow cover after late fall fertilization should be an important management skill on the spring greenup of creeping bentgrass on following year transforming from ski slope to golf hole.