• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.6
• /
• pp.694-700
• /
• 2018

Korea has disposed of medium and low level radioactive waste generated by operating nuclear power plants permanently through the radioactive waste repository located in Gyeongju. However, the maritime transport of radioactive waste is exposed to the risk of marine accidents, and it will be necessary to introduce a system to secure safety from the viewpoint of the function and role of the Korea Coast Guard. Especially, Korea is affected by large-scale marine accidents, such as the Hebei Spirit or Sewol accidents. From this point of view, we analyzed the current status of Korea radioactive waste shipping and examined the response systems of major foreign countries. As a result of examining major cases of accidents, we have operated an Emergency Towing Vessel (ETV) fleet centering on European countries in order to respond urgently to marine casualties that may have social, regional and international effects, such as accidents of similar nuclear material carriers and dangerous cargo ships. It proves a partial effect. Based on this, we propose the introduction of the Korean ETV System. In other words, it is necessary to respond to large-scale marine accidents that could lead to enormous environmental, property, and personal damage, such as marine accidents involving nuclear material ships, large oil tankers, and large passenger ships. For this, it seems necessary to introduce Korea ETV, which can carry out emergency towing, oil pollution control function, large - scale rescue equipment and manpower. This will lead to the enhancement of the Korea Coast Guard response to marine accidents, and will not miss the golden time of the initial response to the national disaster, which will help protect precious people, property and the environment.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.15 no.1
• /
• pp.30-37
• /
• 2012

This paper assessed environmental impact of tidal power plant construction in the western sea of Korea, and diagnosed problems of the related assessment. We also proposed key assessment items (scoping) and system improvement for environmental impact assessment (EIA). The establishment of a broad consensus of the appropriateness and a clear purpose for business is an important aspect of the aptness of using the waters, and the aggressive collecting of opinions of the stakeholder and institutions will have to be fulfilled. In addition, we presented the following scoping plan in order to minimize the negative effects of the marine ecosystem and the conflict between the people who work in the fishing industry which result due to the construction of the tidal power plants. (1) the change in seawater exchange rates and the aspect of erosion/sedimentation which result from the change in the velocity of running fluid, (2) the destruction of spawns/habitats of fish due to the damage of tidal flats, (3) fishery resources, impacts of fishing grounds, and the spread of suspended sediments, etc. will have to be applied to the key assessment items(scoping). In addition, every citizen will have work hard for an establishment of an active plan which achieves the harmony and balance of environmental preservation and for the policy to be applied through changing their consciousness of environmental preservation.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.11 no.4
• /
• pp.191-198
• /
• 2008

To design a reliable $CO_2$ marine geological storage system, it is necessary to perform numerical process simulation using thermodynamic equation of state. $CO_2$ capture process from the major point sources such as power plants, transport process from the capture sites to storage sites and storage process to inject $CO_2$ into the deep marine geological structure can be simulate with numerical modeling. The purpose of this paper is to compare and analyse the relevant equations of state including ideal, BWRS, PR, PRBM and SRK equation of state. We also studied the effect of thermodynamic equation of state in designing the compression and transport process. As a results of comparison of numerical calculations, all relevant equation of state excluding ideal equation of state showed similar compression behavior in pure $CO_2$. On the other hand, calculation results of BWRS, PR and PRBM showed totally different behavior in compression and transport process of captured $CO_2$ mixture from the oxy-fuel combustion coal-fired plants. It is recommended to use PR or PRBM in designing of compression and transport process of $CO_2$ mixture containing NO, Ar and $O_2$.

• Korean Journal of Environmental Biology
• /
• v.19 no.4
• /
• pp.313-320
• /
• 2001

An ecological study was conducted to determine the geographic distribution, community structure, and habitat characteristics of eelgrass, Zostera marina L. beds along the southern coast of Korea. Plants and sediment samples were collected during June 2000 and December 2000 on twenty-eight locations, including two Cheju Island stations, which were used to compare morphological characteristics with habitat types. Z. marina populations existed from the intertidal to subtidal zone, mainly in the bays along the coast and the island, the barrier reef, and the estuary where the water depth was 0.5${\sim}$8.0m. Salinity range in Z. marina beds ranged 18.2 to 34.5%$_o$. Sediments of Z. marina beds contained 49.7${\sim}$99.1% of sand and were classified into sand, muddy sand, and sandy mud. Mean grain size varied from 1.5 to 4.4 phi. Height of vegetation shoots varied from 54.7 to 171.4 cm, depending on water depth, location, substrata and habitat types. quantitative morphological features that enabled recognition of the two phonetic groups were short-narrow leaf type and long-broad leaf type. Statistical analysis indicated that biomass of individual plants and their quantitative morphological characteristics were significantly correlated.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.7
• /
• pp.613-621
• /
• 2016

This research connected network equipment, including CCTV, PAGA, IP-PBX, and Legacy, in order to enable the operation and configuration of internal IP-based network equipment in maritime plants and vessels, both in the field and from remote places, and to allow for the support of remotely controlling such equipment. It also realized an operating program for the integrated network equipment management system to enable the monitoring and control of equipment status, operation condition, and notifications from distant places. By applying the operating program to satellite stations and vessels sailing on the sea, a performance test was conducted to evaluate data loss and transmission/reception delay in the communication section between the land and vessels. As a result, this research verified the normal operation of CCTV control and of real-time monitoring and control of the network equipment, including PAGA, IP-PBX, and Legacy under the FBB and MVSAT environments. It was observed that the transmission of CCTV video images with a large volume of data as well as the transmission and reception of voice data were found to be slightly delayed, indicating the need to develop technology to compress and convert data for real-time transmission and reception.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.7
• /
• pp.916-922
• /
• 2018

Recently, power plant effluent condensers received a Renewable Energy Certificate as components of hydrothermal energy (weighted 1.5 times) as one target item of the Renewable Portfolio Standard (RPS) policy. Accordingly, more attention is being paid to the value of thermal wastewater as a heat source. However, for utilization of thermal wastewater from power plants in high-turbidity areas like the West Sea of Korea, a turbidity reducing system is required to reduce system contamination. In this study, an experimental test was performed over a month on thermal wastewater from power plants located in the West Sea of Korea. It was found that water turbidity was reduced by more than 80 % and that the concentration of organic materials and nutrient salts was partially reduced due to the reduction of floating/drifting materials. To conduct a comparative analysis of the level of contamination of the heat exchanger when thermal wastewater flows in through a turbidity reducing system versus when the condenser effluent flows in directly without passing through the turbidity system, we disassembled and analyzed heat exchangers operated for 30 days. As a result, it was found that the heat exchanger without a turbidity reducing system had a higher level of contamination. Main contaminants (scale) that flowed in to the heat exchanger included minerals such as $SiO_2$, $Na(Si_3Al)O_8$, $CaCO_3$ and NaCl. It was estimated that marine sediment soil flowed in to the heat exchanger because of the high level of turbidity in the water-intake areas.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.4
• /
• pp.395-406
• /
• 2023

The first technological advance to improve the output and efficiency of the latest steam turbines operating in co-generation plants in Korea can be said to be progress in the field of materials that can use high-temperature, high-pressures steam. As a result of design efforts to improve the internal efficiency of steam turbines along with the development of materials, only a few manufacturers of steam turbine have produced high efficiency steam turbines. The internal efficiency of a steam turbine on the steam path operating for a long period of time is gradually lost owing to the limit of mechanical life, and efficiency and output decrease. Therefore, this study aims to develop a model that can analyze the steam flow path performance of HP (High Pressure) and IP (Intermediate Pressure) steam turbine for a co-generation plant using a commercial program and propose a performance calculation method. Owing to the complex performance calculation method of steam turbines, major variables are presented to serve as practically useful references for steam turbine practitioners. In addition, the thermal dynamic analysis(such as heat balance diagram calculation) and the the thermal dynamic calculation required for steam turbine performance calculation and the suitability of the steam turbine performance calculation results were compared with the performance test results.

• Korean Journal of Ecology and Environment
• /
• v.50 no.2
• /
• pp.254-265
• /
• 2017

To elucidate occurrence patterns of naturalized plants in agroecosystems, we surveyed flora in uplands, orchards and rice paddy fields in middle regions (Gyeonggi-do and Chungcheong-do) of Korea in summer and fall from 2013 to 2015. Our results showed that there are 77 species of naturalize plants in 54 genera and 20 families of vascular plants among total 420 species occurred in the agricultural areas composing 18.3% of naturalized index. Community compositions of both native and naturalized plants were different among agricultural types. We suggested that Cerastium glomeratum Thuill., Bidens frondosa L. and Erigeron philadelphicus L. are capable of dispersal to other regions based on our results with getting to broaden distribution of naturalized plants. The mean naturalized index was the highest in the upland (25.1%) followed by in the orchard (23.0%) and the paddy field (16.1%), while the mean number of naturalized species was the highest in the orchard (21.8 species) followed by in the upland (16.6 species) and paddy field (10.3 species). The numbers of naturalized plants in the orchard were increased along with increasing size of the agricultural land and decreasing ecological area rate. In addition, the number of native species was significantly correlated with the number of naturalized species in the upland. Our results would provide useful information to manage dispersion of naturalized plants in agricultural ecosystems.

• Journal of Advanced Marine Engineering and Technology
• /
• v.18 no.5
• /
• pp.12-23
• /
• 1994

The two-phase flow is observed in power plants, chemical process plants, and refrigeration systems etc., and it is very important to solve the heat transfer mechanism of a boiler, an automic reactor, a condenser and various types of evaporators. Recently, the problem of two phase heat transfer is braught up in many regions with development of energy saving technique. In flow boiling system it is necessary to store data in each condition because the heat transfer characteristics of flow boiling region vary by the change of flow pattern and the magnetude of heat flux to tube length, and be subtly affected by the flow and heating condition. So basic study for knowing flow pattern in heat transfer region and the relation between heat transfer characteristic and flow condition is desired to accumulate data in wide variety of liquid and flow system in the study of heat transfer of two phase flow. In this study R-113 was selected as working fluid whose properties were programmed by least square method, and experiment was conducted in the region of mass flow $1.628{\times}10^6$~$4.884{\times}10^6$/kg/$m^2$hr with inlet subcooling 10~3$0^{\circ}C$, sustaining test section inlet pressure to 1.5kg$_f$/$cm^2$abs.

• Journal of Advanced Marine Engineering and Technology
• /
• v.41 no.1
• /
• pp.91-98
• /
• 2017

In this paper, we analyzed underwater multiple sensors acoustic communication technologies for monitoring and control of offshore plants in underwater environments. Information on underwater structure of offshore plants is transmitted and received by multiple sensors at the same time. Using multiple sensors with same frequency, we employed spread spectrum techniques to avoid interferences between these multiple sensors. Owing to the multi-path characteristic in underwater communications, the performance is degraded. In order to improve the performance of underwater multiple sensors communication, we proposed turbo equalized RAKE receiver structures. Assuming that the number of sensors is fixed to three, we conformed the effectiveness of the proposed method as compared to the conventional one.