• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.1
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• pp.107-120
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• 2019

The decommissioning of one nuclear power plant in a multi-unit nuclear power plant (multi-unit NPP) site may pose radiation exposure risk to decommissioning workers. Thus, it is essentially required to evaluate the exposure dose of decommissioning workers of operating multi-unit NPPs nearby. The ENDOS program is a dose evaluation code developed by the Korea Atomic Energy Research Institute (KAERI). As two sub-programs of ENDOS, ENDOS-ATM to anticipate atmospheric transport and ENDOS-G to calculate exposure dose by gaseous radioactive effluents are used in this study. As a result, the annual maximum individual dose for decommissioning workers is estimated to be $2.31{\times}10^{-3}mSv{\cdot}y^{-1}$, which is insignificant compared with the effective dose limit of $1mSv{\cdot}y^{-1}$ for the public. Although it is revealed that the exposure dose of operating multi-unit NPPs does not result in a significant impact on decommissioning workers, closer examination of the effect of additional exposure due to actual demolition work is required. The calculation method of this study is expected to be utilized in the future for planned decommissioning projects in Korea. Because domestic NPPs are located in multi-unit sites, similar situations may occur.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1606-1615
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• 2022

For investigating whether the MARSSIM nonparametric test has sufficient statistical power when a site has a specific contamination distribution before conducting a final status survey (FSS), a novel approach was proposed to predict the release probability of the site. Five distributions were assumed: lognormal distribution, normal distribution, maximum extreme value distribution, minimum extreme value distribution, and uniform distribution. Hypothetical radioactivity populations were generated for each distribution, and Sign tests were performed to predict the release probabilities after extracting samples using Monte Carlo simulations. The designed Type I error (0.01, 0.05, and 0.1) was always satisfied for all distributions, while the designed Type II error (0.01, 0.05, and 0.1) was not always met for the uniform, maximum extreme value, and lognormal distributions. Through detailed analyses for lognormal and normal distributions which are often found for contaminants in actual environmental or soil samples, it was found that a greater statistical power was obtained from survey units with normal distribution than with lognormal distribution. This study is expected to contribute to achieving the designed decision error when the contamination distribution of a survey unit is identified, by predicting whether the survey unit passes the statistical test before undertaking the FSS according to MARSSIM.

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.2859-2865
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• 2021

One of the important issues raised from the Fukushima-Daiichi accident is the safety of multi-unit sites when simultaneous accidents occur at the site and recently a multi-unit PSA methodology is being developed worldwide. Since all operation modes of the plant should be considered in the multi-unit PSA, the accident analysis needs to be performed for shutdown operation modes, too. In this study, a station blackout during the mid-loop operation is selected as a reference scenario. The overall accident progression for the mid-loop operation is slower than that for the full-power operation because the residual heat per mass of coolant is about 6 times lower than that in the mid-loop scenario. Though the fractions of Cs released from the core to the RCS in both operation modes are almost the same, the amount of Cs delivered to the containment atmosphere is quite different due to the chemisorption in the RCS. While 45.5% of the initial inventory is chemisorbed on the RCS surfaces during the full-power operation, only 2.2% during the mid-loop operation. The containment remains intact during the mid-loop operation, though 83.9% of Cs is delivered to the containment.

• Journal of the Korean housing association
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• v.11 no.3
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• pp.53-63
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• 2000

The purpose of this study is to improve design method for renovating an environmental friendly residential space where nature and humans could coexist. In the present study, five deteriorated multi-family housing complexes have been selected and one hundred and thirty eight dwellers have been asked about ecological important factors through the questionnaire. This study presents the adaptable solutions, such as are the enlargement of unit space or area, the renovation of facade, the functional change for dwellings on the ground level, the open piping of circulation systems, the expansion of community facilities(include greenarea), the build up of spatial hierarchy and the housing development set reuse planning forth as a premise, for the aspects of dwelling unit, building block and site planning.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.226-232
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• 2000

The design of agricultural facilities is the consistent activities, which systematically analyze all the actual conditions, design the unit structures, and improve the faming environment through efficient organization of the unit facility. The design of agricultural facilities is composed of site study, preliminary design, primary design, and detail design. Integrated design system can manage and process the information created by and used in all steps of design process. Formal data models of these design activities are important conceptual steps in development of integrated design system. However, most of existing models are not available for agricultural facilities. To support efficiently developing the integrated design system of agricultural facilities, we have developed the Multi-Layered Primitive-Composite mode I through object-oriented analysis of agricultural facilities. The MPC model not only satisfies the characteristics of agricultural facility, such as variety, coupling, informal data, but also improves abilities of integrated design system such as extensibility, flexibility, and granularity. The paper presents a formal definition of the MPC model.

• Korean Institute of Interior Design Journal
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• v.15 no.6 s.59
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• pp.172-177
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• 2006

Most of the Korean multi-dwelling houses have less than 20 years of lifespan. Because the environmental issues such as energy consumption, limited resources, and demolition waste problems became been more and more critical, we now need to focus on long lasting and adaptable buildings. Korean wall bearing apartment buildings are constructed with site cast concrete for core, exterior, and interior together with pipes varied, so when the buildings are old and life style of the users changes, it is difficult to maintain and renovate these buildings. In this study, to resolve the problems described above, two types of Korean long life multi-dwelling housing models which represent improved durability and adaptability responding user's needs and life style changes were proposed with various methods as follows: Either column and beam structure or flat slab structure was used to utilize space better. To make maintenance easier and renovation economical for both public space and each unit, plumbing pipes, ducts, and conduits were clustered at the cores and public corridors with access doors and light weight partitions with steel studs and raised floors or above-ceiling spaces were used in lieu of site cast concrete walls and floor slabs with varied pipes.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1427-1437
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• 2014

Enzymatic hydrolysis of lignocellulosic biomass into fermentable sugars is a key step in the conversion of agricultural by-products to biofuels and value-added chemicals. Utilization of a robust microorganism for on-site production of biomass-degrading enzymes has gained increasing interest as an economical approach for supplying enzymes to biorefinery processes. In this study, production of multi-polysaccharide-degrading enzymes from Aspergillus aculeatus BCC199 by solid-state fermentation was improved through the statistical design approach. Among the operational parameters, yeast extract and soybean meal as well as the nonionic surfactant Tween 20 and initial pH were found as key parameters for maximizing production of cellulolytic and hemicellulolytic enzymes. Under the optimized condition, the production of FPase, endoglucanase, ${\beta}$-glucosidase, xylanase, and ${\beta}$-xylosidase was achieved at 23, 663, 88, 1,633, and 90 units/g of dry substrate, respectively. The multi-enzyme extract was highly efficient in the saccharification of alkaline-pretreated rice straw, corn cob, and corn stover. In comparison with commercial cellulase preparations, the BCC199 enzyme mixture was able to produce remarkable yields of glucose and xylose, as it contained higher relative activities of ${\beta}$-glucosidase and core hemicellulases (xylanase and ${\beta}$-xylosidase). These results suggested that the crude enzyme extract from A. aculeatus BCC199 possesses balanced cellulolytic and xylanolytic activities required for the efficient saccharification of lignocellulosic biomass feedstocks, and supplementation of external ${\beta}$-glucosidase or xylanase was dispensable. The work thus demonstrates the high potential of A. aculeatus BCC199 as a promising producer of lignocellulose-degrading enzymes for the biomass conversion industry.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.3
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• pp.21-28
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• 2008

In MCDA (Multi-Criteria Decision Analysis) based on GIS, building the CM(Criteria Map) which represents the space phenomenon properly is important process to deduce precise and efficient site analysis result. The CM using administrative district data is widely used for site analysis process. But, there are not enough studies on site analysis using dasymetric mapping technique. For MCDA, this study suggests building the CM by using dasymetric mapping technique, which re-assigns the social-economic attribute value to more detail space unit. The suggested method is used for industrial site analysis. The criteria map for workforce and criteria map for the distance to the city were built and criteria map which represents attribute's space distribution pattern is documented. The criteria map is successfully applied to multi-criteria decision making process and eventually the analysis result of proposed suitable industrial site is derived.

• Korean Journal of Human Ecology
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• v.20 no.5
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• pp.1075-1091
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• 2011

The purposes of this study were to investigate the actual state of indoor air quality in semi-underground multi-family housing units in early summer, to analyze the influencing factors, and to make suggestions for improvement. A series of field investigations were conducted in four target units between June 22, 2010, and June 28, 2010. The field investigations included measurements of indoor air quality as well as the observation of architectural characteristics and living conditions. In addition to the field investigation, on-site questionnaire surveys were administrated to residents in 90 units. The findings are summarized as follows: (1) The average $CO_2$ levels in each of the four units ranged from 759ppm to 1885ppm. $CO_2$ levels in three units exceeded the evaluation standard (1000ppm), and one unit was lower than the standard. This unit had smaller number of staying person and a large amount of ventilation than others; (2) the average CO levels in each unit were almost 0ppm, but 0.1~1.1 levels of CO were revealed at several times; (3) the average PM-10 levels ranged from $8{\mu}g/m^3$ to $40{\mu}g/m^3$, which distributes within the standard ($150{\mu}g/m^3$). The influencing factors of PM-10 levels were analyzed as inflow from outside, the use of a gas range, and the residents' activities; (4) therefore, it was evaluated to be necessary to improve ventilation for the indoor air quality of semi-underground housing in aspect of $CO_2$ levels.

• Journal of Radiation Protection and Research
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• v.37 no.3
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• pp.129-137
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• 2012

In the 2007 recommendation, the ICRP evolves from the previous process-based system of practices and intervention to the system based on the characteristics of radiation exposure situation. In addition, ICRP recommends the application of source-related dose constraints under the planned exposure situation as a tool for the optimization of protection to workers and the member of public. In this study, the analysis of radioactive effluents from Korean nuclear power plants and the public dose assessment were conducted in reference with the use of dose constraints. Finally, the measure to implement the dose constraints for the member of public was suggested taking into account multi-unit reactors operating at a single site in Korea.