• Nuclear Engineering and Technology
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• v.40 no.1
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• pp.9-20
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• 2008

Since plutonium accounts for 40-50% of the power produced by uranium fuels, spent fuel contains only residual plutonium. Management of this plutonium is one of the aspects influencing the choice of a fuel cycle back-end option: reprocessing, direct disposal or wait-and-see. Different grades and qualities of plutonium exist depending from their specific generation conditions; all are valuable fissile material. Safeguard authorities watch the inventories of civil plutonium, but access to those data is restricted. Independent evaluations have led to an estimated current inventory of 220t plutonium in total (spent fuel, separated civil plutonium and military plutonium). If used as MOX fuel, it would be sufficient to feed all the PWRs and BWRs worldwide during 7 years or to deploy a FBR park corresponding to 150% of today' s installed nuclear capacity worldwide, which could then be exploited for centuries with the current stockpile of depleted and spent uranium. The energy potential of plutonium deteriorates with storage time of spent fuel and of separated plutonium, due to the decay of $^{241}Pu$, the best fissile isotope, into americium, a neutron absorber. The loss of fissile value of plutonium is more pronounced for usage in LWRs than in FBR. However, keeping the current plutonium inventory for an expected future deployment of FBRs is counterproductive. Recycling plutonium reduce the required volume for final disposal in an underground repository and the cost of final disposal. However, the benefits of utilizing an energy resource and of reducing final disposal liabilities are not the only aspects that determine the choice of a back-end policy.

• Korean Journal of Environmental Agriculture
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• v.27 no.2
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• pp.205-210
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• 2008

Life cycle assessment(LCA) is acknowledged as a valuable tool to quantify the environment impact of agricultural practice as well as final product(biodiesel) considering whole life cycle of the target product. As a preliminary research of LCA study for rapeseed(Brassica napus L.) biodiesel, the methodological issues which have to be regarded with high priority were dealt with. No life cycle inventory(LCI) based on local data are currently available for LCA of rapeseed cultivation, crushing, and conversion to rapeseed methyl ester(RME) in Korea. In this paper, the life cycle of rapeseed and methodological factors which have to be measured for building LCI of each process are provided and discussed, which are including seed, fertilizer, energy use in rapeseed cultivation environment; and crushing, RME conversion, and transportation in biodiesel production.

• Journal of the Korean Society for Railway
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• v.9 no.5 s.36
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• pp.517-523
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• 2006

The sustainable development is a key issue in the whole field of economy, culture and society, which can be accomplished by the improvement of environment. Recently, life cycle assessment(LCA) has been applied to reduce environmental impacts preliminarily by evaluating the environmental performance of a product through its life cycle. In this study, life cycle assessment was performed to analyze quantitatively the environmental impact on the interior panel of electric motor unit(EMU). As a result, the interior panel with aluminum showed the most global warming(GW), while that with phenol and plastic showed high fresh water aquatic ecotoxicity(FAET) and marine water aquatic ecotoxicity(MAET), respectively. Global warming was occurred mainly due to the emission of $CO_2$ by energy consumption. FAET and MAET were caused by the pollutants released from acid-washing and paints coating process. Therefore, an environmental-friendly EMU can be designed considering the environmental impacts of interior panel.

• Journal of the Korea Society for Simulation
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• v.21 no.1
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• pp.1-8
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• 2012

In recent days, global shipbuilding companies have been showing great interest in eco-friendly ship products and trying to reduce environmental pollution - harmful gas and dust in shipbuilding process. Following this trend, Life Cycle Assessment (LCA) was carried out to an application of shipyards layout. LCA is a technique used to assess environmental impacts during the life cycle of products and systems. Until now, LCA has been used through ISO 14040 in somewhat limited industries, such as Building Life Cycle Assessment. Thus, this study analyzes the shipyard layout planning framework and builds life cycle inventory along with the simulation model structure to evaluate environmental impacts.

• Advances in environmental research
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• v.3 no.4
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• pp.367-377
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• 2014

In this study, we investigated a life cycle assessment (LCA) of six roof-waterproofing systems [asphalt (C1), synthetic polymer-based sheet (C2), improved asphalt (C3), liquid applied membrane (C4), Metal sheet with asphalt sheet (N1), and liquid applied membrane with asphalt sheet (N2)]for reinforced concrete building using an architectural model. To acquire accurate and realistic LCA results, minimum units of material compositions for life cycle inventory and real data for compositions of waterproofing materials were used. Considering only materials and energy demands for waterproofing systems per square meter, higher greenhouse gas (GHG) emissions could be generated in the order of C1 > N2 > C4 > N1 > C2 > C3 during construction phase. However, the order was changed to C1 > C4 > C3 > N2 > N1 > C2, when the actual architecture model was applied to the roof based on each specifications. When an entire life cycle including construction, maintenance, and deconstruction were considered, the amount of GHG emission was in the order of C4 > C1 > C3 > N2 > C2 > N1. Consequently, N1 was the most environmental-friendly waterproofing system producing the lowest GHG emission. GHG emissions from maintenance phase accounted for 71.4%~78.3% among whole life cycle.

• Management Science and Financial Engineering
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• v.4 no.2
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• pp.15-42
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• 1998

A joint problem of order delivery, setup reduction, and cost-sharing in a two-echelon inventory system in which a vendor supplies multiple products to a group of buyers is studied here. The basic premise is that buyers have independently implemented setup reduction programs to acquire benefits from small order sizes. Doing so, however, causes the buyers' individually optimal order cycles to be differ from that of the vendor. In conjunction with this, two models are considered. In the first model, a multi-buyers single product situation is considered in which the vendor implements a joint supply cycle policy. However, buyers, as the dominant party, insist after implementing the individually optimal setup reduction that the vendor accept their individually optimal order schedules. In the second model. a multi-products, single buyer situation is considered in which the buyer implements a joint order policy. Here, the vendor, as the dominant party, refuses to cooperate fully with the buyer's individually reduced joint order schedule, and designs his own individually optimal setup reduction mix for each product under a given budget constraint. This led to a study of an integrated Setup Reduction/Break-even Pricing Policy for each situation to eliminate mismatches in individually optimal cycle times.

• Journal of the Korean housing association
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• v.14 no.5
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• pp.65-74
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• 2003

Recently, the environmental conservation has been emphasized over the world. Building industry should carefully reflected the development focused on the economic aspect as well as the environmental considerations. Therefore, it requires the technology development to mitigate the environmental pollution through the reducement of the energy and resources usage amount over the building life cycle. For these, it should be required to set up the analysis methodology to grasp the amount of the environmental pollution and energy and resources in each step of building life cycle. In this paper, it aimed at preparing the analysis process and analyzing the embodied energy and $CO_2$ and $SO_x$ emission according to the building work, field work, mechanical and electrical work on the new building and remodelling, utilizing the inventory analysis which is one of the LCA process.

• Journal of the Korea Safety Management & Science
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• v.19 no.3
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• pp.97-107
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• 2017

This research studies on the demand forecasting for service parts considering parts life cycle, that gets relatively less attentions in the field of forecasting. Our goal is to develop forecasting method robust across many situations, not necessarily optimal for a limited number of specific situations. For this purpose, we first extensively analyze the drawbacks of the existing forecasting methods, then we propose the new demand forecasting method by using these findings and reinforcement leaning technique. Using simulation experiments, we proved that the proposed forecasting method is better than the existing methods under various experimental environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1371-1378
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• 2005

Vertical e-Marketplaces have been expanded because of their enough funds and purchasing power, while horizontal e-Marketplaces have not been grown. On the e-Marketplace which is dealing electronic components with the characteristics of short life cycle and diversities, if an e-Marketplace participant holds a large quantity of the same kinds of components, it will result in lowering competitiveness of the company because of its unuseful inventory. Therefore, as a method for increasing competitiveness of e-Marketplace participants, we proposed the inventory sharing method among the participants, and then designed and implemented it in this paper. For providing inventory sharing function, the e-Marketplace system needs intermediary because each system of participants participating e-Marketplace uses its own DBMS respectively. In this paper, we implemented inventory sharing function using XML, which is a standard for exchanging data, as intermediary, and showed an example of the implemented system.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.2
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• pp.171-178
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• 2014

After the expiration of operating license of a plant, all infrastructures within the plant must be safely dismantled to the point that it no longer requires measures for radiation protection. Despite the fact that Kori 1 and Wolsong 1 are close to the expiration of their operating license, sufficient technologies for radiological characterization, decontamination and dismantling is still under development. The purpose of this study is to develop one of methods for radiological inventory assessment on measuring object by using direct measure of large component with In-Situ measurement technique. Radiological inventory was assessed by analyzing nuclide using portable gamma spectroscopy without dismantling reactor head, and the result of direct measurement was supplemented by performing indirect measurement. Radiochemical analysis were performed on surface contamination samples as well. During the study, radiological inventory of reactor vessel calculated expanding the result. Based on the result and the radioactivity variation of each radionuclides time frame for decommissioning can be decided. Thus, it is expected that during the decommissioning of plants, the result of this study will contribute to the reduction of radiation exposure to workers.