Risk-Based Inspection Modeling for Underground Pipelines

학위논문 (석사)-- 서울대학교 대학원 : 화학생물공학부, 2016. 8. 한종훈.Underground pipeline systems carrying hazardous substances possess a significant thread to surroundings unless a certain level of safety is provided. The pipeline accidents range from small leaks to catastrophic explosions due to which hundreds of people are dead and injured. In order to prevent these accidents, all the countries should be responsible for developing their inspection and maintenance programs and enforcing the pipeline owners to have safe operation through national regulations. In this study, pipeline safety regulations in Germany, US, and Spain are investigated, and a methodology to evaluate the risk levels of pipelines is proposed based on Risk-Based Inspections and Maintenance Procedures for European Industry (RIMAP). The underground pipelines in Ulsan-Onsan Industrial Complex are evaluated using the proposed model. The recommendations for Korean government to build their pipeline safety regulations are also given considering the practices in Europe and US.Chapter 1. Introduction 1 1.1 Research Motivation and Objectives 1 1.2 Major pipeline accidents 3 1.3 Outline of thesis 9 Chapter 2. Buried Pipeline Corrosion & Maintenance 10 2.1 Corrosion Theory 10 2.1.1 Internal Corrosion 11 2.1.2 Subsurface (External) Corrosion 13 2.2 Corrosion Prevention 14 2.2.1 Internal Corrosion Preventions 14 2.2.2 External Corrosion Preventions 16 2.3 Pipeline Inspections 18 2.3.1 Indirect Assessment 20 2.3.2 Direct Assessment 24 Chapter 3. Risk-Based Inspection and Maintenance 30 3.1 Risk Based Inspection (RBI) Model 31 3.1.1 Probability of Failure (PoF) 32 3.1.2 Consequence of Failure (CoF) 39 3.1.3 Risk Determination 47 3.2 Case Study 49 3.3 Discussions on the RBI Model 69 Chapter 4. Pipeline Regulations 73 4.1 Pipeline Regulations in Germany 73 4.1.1 Operational Safety Management (BetrSichV) 73 4.1.2 Ordinance on Systems for handling water-polluting substances (WasgefStAnlV) 76 4.1.3 Sanctions When Legal Requirements Disobeyed 80 4.1.4 Standards / Codes about Separation Distance and Depth of Pipelines 80 4.2 Risk Based Inspection (RBI) Approach in Germany 82 4.3 Recommendations for Korea 83 Chapter 5. Conclusions 85 References 87Maste