As nuclear power plants are operated in Korea, low and intermediate-level radioactive wastes and spent nuclear fuels are continuously generated. Due to the increase in the amount of radioactive waste generated, the demand for transportation of radioactive wastes in Korea is increasing. This can have radiological effect for public and worker, risk assessment for radioactive waste transportation should be preceded. Especially, if the radionuclides release in the ocean because of ship sinking accident, it can cause internal exposure by ingestion of aquatic foods. Thus, it is necessary to analyze process of internal exposure due to ingestion. The object of this study is to analyze internal exposure by ingestion of aquatic foods. In this study, we analyzed the process and the evaluation methodology of internal exposure caused by aquatic foods ingestion in MARINRAD, a risk assessment code for marine transport sinking accidents developed by the Sandia National Laboratory (SNL). To calculate the ingestion internal exposure dose, the ingestion concentrations of radionuclides caused by the food chain are calculated first. For this purpose, MARINRAD divide the food chain into three stages; prey, primary predator, and secondary predator. Marine species in each food chain are not specific but general to accommodate a wide variety of global consumer groups. The ingestion concentrations of radionuclides are expressed as an ingestion concentration factors. In the case of prey, the ingestion concentration factors apply the value derived from biological experiments. The predator's ingestion concentration factors are calculated by considering factors such as fraction of nuclide absorbed in gut, ingestion rate, etc. When calculating the ingestion internal exposure dose, the previously calculated ingestion concentration factor, consumption of aquatic food, and dose conversion factor for ingestion are considered. MARINRAD assume that humans consume all marine species presented in the food chain. Marine species consumption is assumed approximate and conservative values for generality. In the internal exposure evaluation by aquatic foods ingestion in this study, the ingestion concetration factor considering the food chain, the fraction of nuclide absorbed in predator’s gut, ingestion rate of predator, etc. were considered as influencing factors. In order to evaluate the risk of maritime transportation reflecting domestic characteristics, factors such as domestic food chains and ingestion rate should be considered. The result of this study can be used as basis for risk assessment for maritime transportation in Korea.

HNS 사고 후 활용할 수 있는 모니터링 지침 개발을 위해 국내외 HNS 사고 후 해양환경영향평가 및 모니터링 관련 사례를 검토하였다. 그 첫 단계로 해양생물 및 서식처를 중심으로 하는 HNS 사고 후 모니터링 및 해양환경영향평가 지침을 개발하였고, 의사결정자 및 작업실무자들에게 적합하도록 내용을 구성하였다.

본 연구의 목적은 새로운 사고의 위기가 국내 해양안전에 미치는 영향을 분석하기 위함이다. 새로운 사고 위기는 세계 해상운송에서 새롭거나 드물게 또는 예측하지 못한 사건들로부터 유추한 것으로 사전 연구에서 46명의 전문가를 통해서 식별한 것이다. 새로운 해양사고의 위기를 식별하기 위하여 해양안전심판원(KMST)의 통계 데이터를 계산에 사용하였고, IMO의 공식안정성평가기법인 위기지수(RI) = 빈도지수(FI) + 심각성지수(SI)의 개념을 계산에 적용하였다. 통계적인 사고 데이터로부터 FI와 SI의 가중치를 계산한 후 가장 순위가 높은 시나리오를 식별하고 새로운 사고 위기와 시나리오 사이의 관계를 분석하였다. 분석 결과, 가장 순위가 높은 시나리오의 근본적인 원인은 “첨단기술 개발”이었고, 그 결과 “화물 작업 시간 단축”이 발생하는 것으로 나타났다. 이러한 결과는 사전 연구에서 46명의 전문가에 의해 식별한 “영업 경쟁” 및 “선원 문제” 등과 차이가 있음을 보였다.

The key features of maritime accidents are the change of their attributes by new risks from time to time. To prevent maritime accidents in Korea, the impacts by new risks on domestic safety environments should be identified or predicted. The purpose of this paper is to find the hazard factors by new risks on maritime safety in Korea. The meaning of new risks is the elements of accident hazard which is compiled from new or rare or unprecedented events in the worldwide maritime transportations. The problems of new risks are the lacks of optimum countermeasures to mitigate accident risks. Using the questionnaires with 152 event scenarios classified by 20 accident causes, the hazard identification and risk analysis of new risks was performed based on the Formal Safety Assessment (FSA) by IMO. A total of 22 Influence Diagrams, which is to depict the transit flows between accident causes to consequences, is used in the construction of 152 event scenarios. A total of 20 accidents causes is the same contents as the causation factors represented in Statistical Year Book for Maritime Accidents of Korean Maritime Safety Tribunals. After defining the evaluation equations to the response results of questionnaires by 46 experts, the work for risk analysis is carried out. As results from the analysis of 152 scenarios, it is known that the root cause to affect on maritime safety in Korea is the pressure of business competition and it led to the lacks of well experienced crews, the overload of vessel operations and crew's fatigue. In addition, as results from the analysis of 20 accident causes, the three accident causes are to be candidate as main issues in Korea such as the inadequate preparedness of departure, the neglecting of watch keeping in bridge and the inadequate management of ship operations. All of the results are thought to be as basic hazard factors to safety impediments. It is thus found that the optimum Risk Control Options to remove the hazard factors and to mitigate consequences required are the following two factors: business competition and crewing problems.