• Nuclear Engineering and Technology
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• v.8 no.2
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• pp.101-116
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• 1976

An attempt is made to analyze the unit nuclear power cost of the Go-ri units 1 and 2 in terms of a set of model data. For the calculational purpose, the power cost is first decomposed into the cost components related to the plant capital, operation and maintenance, working capital requirements, and fuel cycle operation. Then, POWERCO-50 computer code is applied to enumerate the first three components and MITCOST-II is used to evaluate the fuel cycle cost component. The specific numerical results are the fuel cycle cost of Go-ri unit 2 for three alternative fuel cycles presumed, levelized unit power cost of units 1 and 2, and the sensitivity of the power cost to the fluctuation of the model data. Upon comparision of the results with the power cost of the fossil power plants in Korea, it is found that the nuclear power is economically preferred to the fossil power. Nevertheless, the turnkey contract value of Go-ri unit 2 appears to be rather expensive compared with the available data on the construction cost of the PWR plants. Therefore, it is suggested that, in order to make the nuclear power plants more attractive in Korea, the unfavorable contract of such kind must be avoided in the future introduction of the nuclear power plant. Capacity factor is of prime importance to achieving the economic generation of the nuclear electricity from the Go-ri plant. Therefore, it is concluded that more efforts should be directed to make the maximum use of the Go-ri plant.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.9
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• pp.817-824
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• 2009

To prevent turbidity breakthrough in a depth filter caused by hydraulic shock loads, influence of turbidity and particle number in filtrate by variation of operating filter number depending on inflow change was investigated. Inflow quantity at the S water treatment plant (WTP) was varied and ratio of maximum/minimum inflow quantity was 2.2, therefore filtration velocity was also subsequently changed. The S WTP changed operating filter number depending on inflow variation to minimize change of filtration velocity. Particle breakthrough was not severe when operation system was changed, out-of-operation and re-start of filter was repeated depending on inflow quantity. Slight particle breakthrough was noticed when re-start of filter was implemented at the filter that had a cumulative filtration run time of less than 10 h or more than 50 h. This can be attributed to the inadequate ripening and over accumulation of particles on media. Therefore, it is more efficient to choose a re-starting filter basin which has cumulative filtration run time more than 10 h or less than 50 h to reduce particle breakthrough. Filter number variation depending on inflow change was proven to be a method for improvement of unit filter run volume (UFRV).

• Journal of Energy Engineering
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• v.26 no.2
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• pp.1-11
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• 2017

While they are becoming more viable, synthetic natural gas (SNG) plants, with their high temperatures and pressures, are still heavily dependent on advancements in the state-of-the-art technologies. However, most of the current work in the literature is focused on optimizing chemical processes and process variables, with little work being done on relevant mechanical damage and maintenance engineering. In this study, a combination of pipe system stress analysis and detailed local stress analysis was implemented to prioritize the inspection locations for main pipes of SNG plant in accordance to ASME B31.3. A pipe system stress analysis was conducted for pre-selecting critical locations by considering design condition and actual operating conditions such as heat-up and cool-down. Identified critical locations were further analyzed using a finite element method to locate specific high-stress points. Resultant stress values met ASME B31.3 code standards for the gasification reactor and lower transition piece (bend Y in Fig.1); however, it is recommended that the vertical displacement of bend Y be restricted more. The results presented here provide valuable information for future risk based maintenance inspection and further safe operation considerations.

• Environmental Engineering Research
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• v.11 no.3
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• pp.134-142
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• 2006

The treatment of high-strength swine wastewater by anaerobic digestion combined with an aquatic plant system was investigated. Anaerobic digestion of swine wastewater gave volatile solids (VS) removal efficiencies of 43.3%, 52.1% and 54.5% for hydraulic retention times (HRTs) of 20, 30, 40 days, respectively. The removal efficiencies of VS, total chemical oxygen demand (TCOD) and soluble chemical oxygen demand (SCOD) decreased with increasing VS volumetric loading rate (VLR). Higher organic removal efficiency was observed at longer HRTs for the same VS volumetric loading rate. As VS volumetric loading rate increased, biogas production increased and the methane content of the biogas decreased. Experiments using duckweed (Lemna species) as an aquatic macrophyte gave the following results. In the case of nitrogen, removal efficiency was above 60% and effluent concentration was below 10.0 mg/L when the influent ammonia-N loading was about $1.0\;g/m^2/day$. In the case of phosphorus, removal efficiency was above 55% and effluent concentration was below 2.0 mg/L when the influent $PO_4$-P loading was about $0.15\;g/m^2/day$. In addition, crude protein and phosphorus content of duckweed biomass increased from 15.6% to 41.6% and from 0.8% to 1.6%, respectively, as the influent nutrient concentration increased. The treatment of high-strength swine wastewater by anaerobic digestion combined with an aquatic plant system offers good performance in terms of organics and nutrient removal for relatively low operation and maintenance costs. The results indicate that under appropriate operational conditions, the effluent quality is within the limits set by Korean discharge criteria.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.270-273
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• 2006

This paper presents a gas turbine data acquisition and monitoring system using a LabVIEW programming. The developed real-time monitoring system entitled a C-Tune DAS plays an important role to make an analysis of the real-time operation of the gas turbine under maintenance. The LabVIEW based software is divided into three parts according to their original functions; Data acquisition, Data analysis and display, and Data storage. The data acquisition part receives data from a PMS (Plant Management System) server and two cFPs (Compact-Field Point). To verify the validity of the developed system, it is applied to gas turbines in the combined cycle power plant in Korea.

• Journal of the Korean Society of Safety
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• v.36 no.5
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• pp.71-78
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• 2021

There are regularly planned overhaul periods in thermal power plants, which involve the maintenance of the boiler of the power plants. However, thermal power plants workers are always exposed to risk during overhaul periods owing to the narrow space and significant dust inside the boiler. Therefore, it is essential to develop a safety monitoring system that is suitable for operating in this type of environment. In this study, we developed not only a worker three-dimensional (3D)-location monitoring system that can monitor and record the entry/exit of workers, their 3D-location, and fall accidents but also a method to secure the working environment and operation efficiency. This system comprises of a worker tag, which was equipped with an inertial measurement unit, a barometric pressure sensor, and a Bluetooth low energy (BLE), and the tags were given to each worker. In addition, the location of workers inside the boiler was measured using a pedestrian dead reckoning (PDR) method and BLE beacons. The location data of the workers tag were transmitted to the integrated database (DB) server through a gateway, and to the administrator monitoring system. The performance of the system was demonstrated inside an actual thermal power plant boiler, and the accuracy and reliability of the system were verified through a number of repeated tests. These results provide insights on designing a new system for monitoring enclosed spaces.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.4
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• pp.397-406
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• 2016

Diverse stakeholders engaged in design, construction, and operation and maintenance of offshore plants typically operate heterogeneous plant 3D CAD systems. Engineering, procurement, and construction (EPC) companies are required to submit plant design result to the owner in the form of a plant 3D CAD model, as specified in the contract. However, because of the limitations of data interface of plant 3D CAD systems, EPC companies frequently perform manual remodeling to fulfill the terms and conditions of the contract. Therefore, comparison should be performed between the source plant 3D CAD model and the remodeled plant 3D CAD model to prove the validity of the remodeled plant 3D CAD model. To automate the comparison process, we have developed a system for quantitatively assessing the similarity of the plant 3D CAD models. This paper presents the architecture and detailed functions of the system. In addition, experimental results using this system are explained.

• Journal of Animal Environmental Science
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• v.15 no.3
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• pp.281-288
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• 2009

The objective of this study is to predict the expansion possibility of treatment capacity in public livestock manure treatment plant (PLMTP) integrated individual farmhouses. According to the treatment efficiency and cost reducing effect, expansion possibility was examined using three cases; (i) decrease of influent concentration from 20,000 mg/L BOD to 1,000 mg/L BOD, (ii) maintenance of low concentration influent with minimum revising existing facilities (BIOSUF) and (iii) maintenance of low concentration influent without revising existing facilities (liquid corrosion method, LCM). In BIOSUF, the treatment capacity increased from 130 ton/day to 300 ton/day. Also, LCM resulted in expansion of treatment capacity from 210 ton/day to 250 ton/day while that of designed concentration influent decreased from 210 ton/day to 190 ton/day. The treatment costs were 14,674 won/ton and 9,929 won/ton for BIOSUF and LCM, respectively. After some revisions, it will be changed to 7,221 won/ton and 8,277 won/ton. Therefore, it must be considered that the livestock manure treats to low concentration and flows into PLMTP for the efficient operation and reducing treatment cost.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.177-179
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• 2018

After Fukushima nuclear accident at 2011, nuclear industrial has been focused on operation and maintenance phase, not design and construction phase. Continued good operating performance of nuclear power plants has been the best critical issue to nuclear utilities. Replacement for complete components as well as parts of components is being procured because nuclear utilities must maintain safety and reliability of operating nuclear power plants. However, many suppliers and manufacturers are giving up a nuclear quality assurance program under reduction in new construction of nuclear power plants. It is able to be increased difficulty in procuring spare parts to support operations and maintenance of nuclear power plants. Over 20% of nuclear power plant equipment in some countries is obsolete. Owing to obsolescence of nuclear safety-related items and/or withdrawing a nuclear quality assurance program of suppliers and manufactures, some replacement item and part might be procured to the item not covered by appendix B to USNRC 10 CFR Part 50. Under various methods of the nuclear repair and replacement methodology, utilities are supposed to establish a typical program for a repair and replacement of an electrical equipment and its parts in conjunction with a nuclear quality assurance. Concerning this typical program, this study suggests the repair and replacement methodology of electrical equipments used in nuclear power plants by procurement of a power supply, based on nuclear regulations, codes, standards, guidelines, specific and general technical information, etc..

• Corrosion Science and Technology
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• v.18 no.6
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• pp.221-227
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• 2019

During the operation, maintenance and decommissioning of nuclear power plant radioactive contaminated waste is produced. This waste is stored in an underground repository 60-100 meters below the surface. The metallic portion of this waste comprises mostly carbon and stainless steel. A long-term field exposure showed high corrosion rates, general corrosion up to 29 ㎛ a^-1 and localized corrosion even higher. High corrosion rate is possible if microbes produce corrosive products, or alter the local microenvironment to favor corrosion. The bacterial and archaeal composition of biofilm formed on the surface of carbon steel was studied using 16S rRNA gene targeting sequencing, followed by phylogenetic analyses of the microbial community. The functional potential of the microbial communities in biofilm was studied by functional gene targeting quantitative PCR. The corrosion rate was calculated from weight loss measurements and the deposits on the surfaces were analyzed with SEM/EDS and XRD. Our results demonstrate that microbial diversity on the surface of carbon steel and their functionality is vast. Our results suggest that in these nutrient poor conditions the role of methanogenic archaea in corrosive biofilm, in addition to sulphate reducing bacteria, could be greater than previously suspected.