• Journal of the Korean Institute of Gas
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• v.14 no.4
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• pp.18-23
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• 2010

After conducting QRA(quantitative risk assessment) for the high pressure urban gas pipelines planned to be installed, RMMs(risk mitigation measures) when the societal risk is outside the acceptable region have been derived in this paper. Also risk reduction rates are calculated for each RMM. As a result of QRA, we find out that damaged distance caused by radiational heat is largely dependent upon the wind velocity and the atmospheric stability. The measure that has the highest risk reduction effect is No. 10 which includes pipeline corrosion monitoring, MOV(motor operated valve) installation and the method to protect pipeline damage caused by third-party mechanical interference, and which shows 75 % of risk reduction effect.

• Journal of the Korean Institute of Gas
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• v.15 no.1
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• pp.15-21
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• 2011

Cost-benefit analysis (CBA) has been performed in order to decide whether the ILI (in-line inspection) suggested as risk mitigation measure (RMM) from quantitative risk assessment is reasonably practicable. As a result of CBA, we could find out the reasonable intervals of implementation of ILI. In order to assess the benefit, value of preventing a fatality (VPF), which measures value of human life, has been used. The adequate VPF figure of high pressure urban gas pipelines for CBA used in this paper is two billion won. As a result of 2 case studies, we found that the most reasonable intervals of ILI suggested as RMM were 13 years or 15 years.

• Journal of the Korean Institute of Gas
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• v.15 no.2
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• pp.40-46
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• 2011

The purpose of CBA(cost-benefit analysis) in risk assessment is to show whether the benefits of implementing additional risk reduction methods(RRMs) derived through risk assessment outweigh its costs and it is proper to implement the methods. In this paper CBA has been conducted in order to select the most effective and reasonable RRM as implementing the RRM derived after QRA for the high pressure urban gas pipelines. As conducting QRA again by applying the derived RRMs, No. 10 measure which includes pipeline corrosion monitoring, MOV(motor operated valve) installation and the method to protect pipeline damage caused by third-party mechanical interference has showed the highest risk reduction effect. Also it has been considered to be reasonably practicable by conducting CBA and then is selected as the most effective and reasonable RRM on the objects of this paper.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.2
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• pp.121-129
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• 2000

The robotic automation in NonDestructive Testing(NDT) is a promising field of research and it helps to expand the applications of NDT enormously. Especially, in the case of pipelines which are widely used in various industrial facilities, it is required to secure adequate ways of inspection in the usual maintenance activitites. In this paper, we present a robot system for inpipe inspection of underground urban gas pipelines. The robot is configured as an articulated structure like a snake with a tether cable. Two active driving vehicles are located in front and rear of the system, respectively and passive modules such as a NonDestructive Testing module and a control module are chained between the active vehicles. The proposed system has outstanding mobility by employing a new steering mechanism called Double Active Universal Joint, which makes it possible to cope with complicated configurations of underground pipelines. Characteristic features of the system are described and the construction of the system is briefly outlined.

• Earthquakes and Structures
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• v.20 no.1
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• pp.109-122
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• 2021

Significant progress in the oil and gas industry advances the application of pipeline into an intelligent era, which poses rigorous requirements on pipeline safety, reliability, and maintainability, especially when crossing seismic zones. In general, strike-slip faults are prone to induce large deformation leading to local buckling and global rupture eventually. To evaluate the performance and safety of pipelines in this situation, numerical simulations are proved to be a relatively accurate and reliable technique based on the built-in physical models and advanced grid technology. However, the computational cost is prohibitive, so one has to wait for a long time to attain a calculation result for complex large-scale pipelines. In this manuscript, an efficient and accurate surrogate model based on machine learning is proposed for strain demand prediction of buried X80 pipelines subjected to strike-slip faults. Specifically, the support vector regression model serves as a surrogate model to learn the high-dimensional nonlinear relationship which maps multiple input variables, including pipe geometries, internal pressures, and strike-slip displacements, to output variables (namely tensile strains and compressive strains). The effectiveness and efficiency of the proposed method are validated by numerical studies considering different effects caused by structural sizes, internal pressure, and strike-slip movements.

• Journal of the Korean Institute of Gas
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• v.21 no.6
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• pp.30-38
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• 2017

Established in the 1960s, high pressure underground pipelines in Ulsan and Yeosu industrial estate are underground as toxic gas as well as combustible gas that is heavier than city gas and low combustion range. Especially, industrial pipelines occupy more than 20 years old pipes. In this way, the industrial estate pipeline was installed before the introduction of the supervision of construction, However, unlike the city gas pipeline, the pipeline is managed without any legal obligation. In this study, the safety management status of high pressure underground pipelines and urban gas underground pipelines in the industrial estate is analyzed and comparison of laws, extent of damage impact, using the pipe inspection model for pipe inspection of high pressure piping system with the existing piping system. it is intended to cuntribute to improving the safety of industrial estate are underground pipeline.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.12
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• pp.2019-2029
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• 2001

Up to now a wide variety of researches on inpipe inspection robots have been introduced, but it still seems to be difficult to construct a robot providing mobility sufficient to navigate inside the complicated configuration of underground pipelines. This paper introduces a robot called MRINSPECT IV(Multifunctional Robotic Crawler for inpipe inSPECTion IV) for the inspection of urban gas pipelines with a nominal 4-inch inside diameter. The proposed robot can freely move along the basic configuration of pipelines such as along horizontal or vertical pipelines. Moreover it can travel along reducers, elbows, and steer in the branches by modulating the speeds of driving modules. Especially, its capability for steering in tile three-dimensional pipeline configuration has a competative edge over the other ones and provides excellent mobility in navigation. Its critical points in the design and construction are introduced and results of experiments are given.

• Journal of the Korean Institute of Gas
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• v.18 no.3
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• pp.67-74
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• 2014

Buried natural gas pipelines in densely populated urban areas have serious hazards of property damages and casualties generated by release, dispersion, fire and explosion of gas caused by outside or inside failures. So as to prevent any accident in advance, managers implement danger management based on quantitative risk analysis. In order to evaluate quantitative risk about buried natural gas pipelines, we need calculation for radiant heat and pressure wave caused by calculation for release rate of chemical material, dispersion analysis, fire or explosion modeling through consequence analysis in priority, in this paper, we carry out calculation for release rate of pressured natural gas, radiant heat of fireball based in accident scenario of actual "San Bruno" buried high pressured pipelines through models which CCPS, TNO provide and compare with an actual damage result.

• Journal of the Korean Institute of Gas
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• v.13 no.3
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• pp.22-27
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• 2009

Recently Urban Gas Business Companies have been allowed to construct High Pressure Natural Gas pipelines, if they adopt the Risk Reduction Measures(RRMs) recommended by Korea Gas Safety Corporation(KGS) after safety assessment. This paper presents a Cost Benefit Analysis(CBA) method, when KGS performs safety assessment and recommends RRMs to Safety Appraisal Committee, to help the Committee make judgements on whether the proposed RRMs are reasonably practicable. We carried out quantitative risk assessment to high pressure natural gas pipelines as a case study and analysed cost benefit for the suggested RRMs. In conclusion, we found out the presented CBA method using PF was proper in Korea.

• Journal of the Korean Institute of Gas
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• v.18 no.5
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• pp.12-19
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• 2014

To minimize the risk of corrosion on buried pipeline and to maximize the efficiency of cathodic protection, various indirect inspection techniques have been used for decades. In the United States, 49 CFR has regulated the external corrosion direct assessment for buried pipelines. In Korea, there is no provision for external corrosion direct assessment but there is only, according to the KGS Code, provision that if the survey of the defects of buried pipeline and the leakage test for the pipe were conducted, it is deemed to leakage inspection. We, therefore, have suggested external corrosion direct assessment method appropriate to domestic status through the survey of the regulations and standards of UK and the USA and the investigation of domestic situation on coating damage detection method. The proposed external corrosion direct evaluation method was used as the basis when introducing the precision safety diagnosis regulation for the medium-pressure pipe in Korea.