침몰선박 잔존유 회수작업 평가모듈 개발에 관한 연구

Abstract

It is a global trend that ships are becoming larger in order to increase the efficiency of cargo transport between countries in the world. The number of large ships entering and departing from trading ports is also gradually increasing. In the process of domestic and foreign ships sailing in the domestic coast area, not only oil tankers, but also various large cargo ships and passenger ships, can sink to the seabed at any time with cargo oil or fuel oil loaded due to negligence, accident or bad weather. Most large ships in the world using heavy oil (Bunker-C) as fuel and tankers with a large amount of cargo oil loaded can sink. This hazardous substances in a ship can leak into the sea at any time on the process of sinking or after skinking. In this case, if there are environmentally sensitive areas such as fishing ground or seaweed farms, that areas may get environmental damage. For this reason, from 2015, Korea government has been conducting on-site investigations and risk assessments for 78 sunken vessels assumed to contain harmful substances in hull among the about 2,200 sunken vessels that have already sunk in the sea of Korea. It is estimated that there are about 4,000 tons of trapped-oil in the 78 vessels in Korea designated as the detailed inspection target vessels. Accordingly, the Korea government regularly conducts a detailed inspection on 78 vessels within the available budget every year. At the same time, in the case of sunken vessels whose trapped-oil has been confirmed, the Korea government is making efforts to safely and promptly remove them. In general, when oil in a ship spills on sea surface and flows into the coastal area, Korea coast guard and special oil response organizations perform response action systematically in accordance with the relevant laws, regulations, and manuals with advanced oil response operation methods and specially designed equipment based on their know-how accumulated over a long period of time. So, research on this sector is proceeding continually. However, research on generalization and standardization of methods and procedure for recovery of trapped-oil in sunken vessels, which can be said to be a representative type of underwater oil response operation, is relatively not enough. Accordingly, in this paper, the study was proceeded in two different ways for sustainable systemic upgrade on trapped-oil recovery operation from sunken vessels. In the first way, It tried to standardization of oil recovery operation method and procedure from a sunken vessel which is possible to use or apply in the general ship-sinking situation through the process of comparative analysis of the recovery method and procedure applied to various domestic and foreign trapped-oil recovery cases that have been safely and successfully carried out in the past. In the second way, the initiative version of evaluation module for recovery operation process was designed to derive key factors for each detailed process of the 3 basic recovery operation steps(preparation, implementation, completion) and to construct assessment indicators for evaluating key factors for each detailed process using quantitative output data produced throughout the general trapped-oil recovery operation. While the preliminary risk assessment for sunken vessels is also continuously conducted according to the assessment standards under the relevant laws in Korea, there is no such a certain assessment criteria for the method and work procedure of overall trapped-oil recovery from sunken vessels in Korea subject to risk reduction measures. In general, we qualitatively judge the adequacy and efficiency of the overall recovery operation method and work procedure based on experience of relative specialists. The development of a quantitative assessment module that can evaluate the efficiency and appropriateness of the overall operation process by using various quantitative data from the recovery operation is necessary in any certain form. Lastly, the usefulness of the standardization result and assessment module for the general trapped-oil recovery operation from sunken vessels researched through this study were applied to recent actual oil recovery operation case that was safely and successfully carried out with only domestic residual oil recovery technic and equipment in the sea area of Busan in 2019 and efficacy was confirmed. In addition, the standardization result and evaluation module for the trapped-oil recovery operation from the sunken vessels designed through this study under the general conditions can be used as a post-evaluation method for the recovery operation as well as the selection of the efficient and appropriated trapped-oil recovery operation. Furthermore, if the continuous accumulation and feedback efforts of the assessment results of various oil recovery cases to be carried out in the future in sea of Korea are accompanied, it is thought that it will be possible to contribute to improving the safety, efficiency, and field adoptability of the domestic sunken vessel’s trapped-oil recovery operation. Starting with this study, additional research on trapped-oil recovery operation from sunken vessels, a representative type of underwater oil response operation, will remove trapped-oil from sunken vessels such as time bombs in sea of Korea safely and efficiently to preserve Korea's marine environment.