• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.220-225
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• 2022

Perlite is one of the major constituents of the radioactive thermal insulation waste (RTIW) originating from nuclear power plants and, for proper waste management, a significant reduction in its volume is required prior to disposal. In this work, the volume reduction of perlite is studied by high-temperature treatment method with using K₂CO₃ as a flux. The perlite is ground with 0-30 wt% K₂CO₃, and differential thermal analysis/thermogravimetric analysis is used to monitor the glass transition temperature (T_g) and weight loss. The Tg varied between ~772.2 and 837.1 ℃ with the minima at ~643.5 ℃ with the addition of ~10 wt% K₂CO₃. It is observed that compared to the pure perlite the volume reduction ratio (VRR) increases with the addition of K₂CO₃. The VRR of 11.20 is observed with 5 wt% K₂CO₃ at 700 ℃, as compared to VRR of 5.56 without K₂CO₃ at 700 ℃. The X-ray photoelectron spectroscopy and scanning electron microscopy are used to characterize perlite samples heat-treated without/with 5 wt% K₂CO₃ at 700 ℃. Moreover, the atomic absorption spectroscopy indicates that the proposed heat-treatment procedure is able to completely retain the radionuclides present in the perlite RTIW.

• Advances in concrete construction
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• v.9 no.5
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• pp.479-489
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• 2020

Studies have proved that the mechanical properties of concrete, suddenly is dropped off with employing waste materials as replacements. The effectiveness of fibre addition on the structural stability of concrete has been indicated in recent investigations. There are different waste aggregates and fibres as plastic, rubber tire, coconut, and other natural wastes, which have been evaluated throughout the last decades. The fibres incorporation has a substantial effect on the properties of concrete mix subjected to different loading scenarios. This paper has reviewed different types of wastes and the effect of typical fibres including Poly Ethylene Terephthalate (PET), rubber tire, and waste glass. Furthermore, waste plastic and waste rubber has been especially studied in this review. Although concretes containing PET fibre revealed a reduction in compressive strength at low fibre fractions, using PET is resulted to micro-cracking decrement and increasing flexibility and flexural strength. Finally, according to the reviews, the conventional waste fibres are well-suited to mitigated time-induced damages of concrete and waste fibres and aggregates could be a reliable replacement for concrete.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4173-4180
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• 2023

The stability of engineered barriers in high-level radioactive waste disposal systems can be influenced by the decay heat generated by the waste. This study focuses on the thermal analysis of various canister designs to effectively lower the maximum temperature of the engineered barrier. A numerical model was developed and employed to investigate the heat dissipation potential of copper rings placed across the buffer. Various canister designs incorporating copper rings were presented, and numerical analysis was performed to identify the design with the most significant temperature reduction effect. The results confirmed that the temperature of the buffer material was effectively lowered with an increase in the number of copper rings penetrating the buffer. Parametric studies were also conducted to analyze the impact of technical gaps, copper thickness, and collar height on the temperature reduction. The numerical model revealed that the presence of gaps between the components of the engineered barrier significantly increased the buffer temperature. Furthermore, the reduction in buffer temperature varied depending on the location of the gap and collar. The methods proposed in this study for reducing the buffer temperature hold promise for contributing to cost reduction in radioactive waste disposal.

• Korean Journal of Organic Agriculture
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• v.28 no.4
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• pp.535-553
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• 2020

In this study, the characteristics of the waste sector CDM project were analyzed through cluster analysis of the waste sector CDM project and the analysis of the CDM investment cost in waste sector using CDM project data registered with UNFCCC since 2008 when EU ETS phase 2 began. As of September 2020, 772 cases of CDM projects in waste disposal and disposal are registered. Biogas technology is the largest, followed by livestock manure processing and biomass production technology. The results of the cluster analysis are summarized as follows: First, on average, projects utilizing AWMS technology are small in size and relatively low in investment costs. This is judged to be relatively low investment costs due to previously attracted foreign investment capital. Second, the average investment cost of CDM projects considered along with waste (No.13), the energy industry (No.1) and agriculture (No.15) was higher than those involving only waste. The analysis of the factors determining the investment cost of the waste sector CDM project showed that, as with cluster analysis, the AWMS technology, which is a livestock manure treatment technology, was lower in the investment cost than those that use other technologies. As a result of multiple regression analysis, the investment cost of the CDM project was analyzed lower in the order of biomass, AWMS, LFG and biogas. Also, the higher the investment cost for CDM projects linked to waste, energy and agriculture, and the better the investment environment, the higher the investment cost. Although no statistical feasibility was obtained, the larger the annual emission reduction, the lower the CDM investment cost.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.1
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• pp.77-84
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• 2010

Reduction of oxides has been investigated for the volume reduction and recycling of the spent oxide fuel from commercial nuclear power plants. Various oxide reduction methods were proposed and KAERI (Korea Atomic Energy Research Institute) is currently developing an electrochemical reduction process using a LiCl-$Li_2O$ molten salt as a reaction medium. The electrochemical reduction process, the front end of the pyroprocessing, can connect the PWR (Pressurized Water Reactor) oxide fuel cycle to a metal fuel cycle of the sodium cooled fast reactor. This paper summarizes KAERI efforts on the development, improvement, and scale-up of the oxide reduction process.

• Korean Journal of Construction Engineering and Management
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• v.9 no.1
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• pp.77-86
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• 2008

On account of increasing interest of substantiality in these day, it is needed to make an effort to establish an environmentally sustainable production system for the construction works. Although practical affairs and researches are in progress to reduce and recycle construction wastes, as a result of a research, there are still obstructive factors on waste reduction and recycling which they don't interact efficiently between waste disposal process of the construction area and waste disposal company. As a plan to revitalize reduction and recycling of construction wastes, this research focuses on finding obstructive factors and giving solutions to reduce and recycle construction wastes which comes from construction process and construction industries. To meet the needs of the research, firstly relatively significant construction wastes (concrete, soil, brick, block, asphalt, plastic, lumber) were identified. On site level interviews with management of disposal companies and construction sites were conducted as well, focusing on typical waste disposal process. Throughout this interviews, obstructive factors were conducted. A result of the research, the authors suggest an improved approach on disposal and recycling for construction waste by prioritizing the identified factors and ranking the importance level of each factor. And, by identifying factors obstructing reduction and recycle of construction wastes, this research suggests improved disposal process of construction waste.

• Journal of Nuclear Fuel Cycle and Waste Technology
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• v.1 no.1
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• pp.75-82
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• 2013

A large quantity of radioactive waste was generated during the decommissioning of the KRR and UCF. The radioactive waste was packed into 200 liter drums and 4m3 containers and these were temporarily stored onsite until their final disposal in the national repository facility. Some of the releasable waste was freely released and utilized for non-nuclear industries. The combustible wastes were treated by the utilization of an incinerator with a capacity of on average 20 kg/hr.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.3
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• pp.85-91
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• 2002

This study is performed to evaluate characteristics of plantable concrete using waste stone and stone dust. The test result shows that the void ratio is decreased as the size of waste stone smaller and the content of stone dust increased. The strength of neutralized plantable concrete is decreased by approximately 4∼5% than that of the normal plantable concrete. The reduction effect of pH value is achieved by chemical treatment. Also, the plant is grown well with increase of the void ratio and size of waste stone.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.563-568
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• 2000

Animal waste is a major agricultural waste or wastewater that requires appropriate treatment to prevent environmental pollution. In this presentation, it is examined if incineration of manure compost is an alternative to treatment of animal waste. Heating values of selected biomass including manure compost were obtained using a bomb calorimeter. Based on heating values of manure and manure compost, ranging from 1200 - 1500 kcal/kg on wet base, incineration could be an alternative for animal waste treatment if available land is limited for land application and sufficient reduction of water content in manure compost.

• Journal of the Korea Concrete Institute
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• v.13 no.3
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• pp.213-220
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• 2001

Incorporation of wastes glass aggregate in mortar may cause crack and this may result in the strength reduction due to alkali-silica reaction(ASR) and expansion. The purposes of this study were to investigate the properties of alkali-silica expansion and strength loss through a series of experiments which had a main experimental variables such as waste glass aggregate contents, glass colors, fiber types, and fiber contents. The steel fibers and polypropylene fibers were used for constraining the ASR expansion and mortar cracking. From the result, green waste glass was more suitable than brown one because of low expansion. And in this accelerated ASTM C 1260 test of waste glass, pessimum content can not be found. Also, when used the fibers with waste glass, there is an effect on reduction of expansion and strength loss due to ASR between the alkali in the cement paste and the silica in the waste glass. Specially, adding 1.5 vol.% of steel fiber to 20% of waste glass, the expansion ratio was reduced by 40% and flexural strength was developed by up to 110% comparing with only waste glass(80$\^{C}$ H$_2$O curing).