• Journal of Korean Society of Water and Wastewater
• /
• v.33 no.4
• /
• pp.259-268
• /
• 2019

One of the most effective methods to consistently ensure the safety of a tap water supply can be achieved by application of a comprehensive risk assessment and risk management approach for drinking water supply systems. This approach can be termed water safety plans(WSP) which recommended by WHO(world health organization) and IWA(international water association). For the introduction of WSP into Korea, 150 hazards were identified all steps in drinking water supply from catchment to consumer and risk assessment tool based on frequency and consequence of hazards were developed. Then, developed risk assessment tool by this research was implemented at a water treatment plant($Q=25,000m^3/d$) to verify its applicability, and several amendments were recommended; classification of water source should be changed from groundwater to stream to strengthen water quality monitoring contaminants and frequencies; installation of aquarium to monitor intrusion of toxic substances into raw water; relocation or new installation on-line water quality analyzers for efficient water quality monitoring; change of chlorination chemical from solid phase($Ca(OCl)_2$) to liquid phase(NaOCl) to improve soundness of chlorination. It was also meaningful to propose hazards and risk assessment tool appropriate for Korea drinking water supply systems through this research which has been inconsistent among water treatment authorities.

• Computers and Concrete
• /
• v.27 no.1
• /
• pp.1-12
• /
• 2021

This work presents a safety assessment of an underground tunnel subjected to a ballistic missile attack employing the numerical approach. For the impact simulation, a box shaped reinforced concrete (RC) structure with a cross section dimension of 8.0×10.0 m under a soil layer that was attacked by a SCUD missile was modeled using finite element (FE) software LS-DYNA. SCUD missile is one of a series of tactical ballistic missiles developed by Soviet Union during the Cold War, which is adopted for a short-range ballistic missile. The developed FE simulation for the penetration depth of the missile impacting into the soil structure was verified from the well-known formula of the penetration prediction. The soil-structure interaction, the soil type, and the impact missile velocity effects on the penetration depth of the missile into the different soil types were investigated. The safety assessment of the underground tunnel was performed with regard to the different depths of the underground tunnel. For each missile velocity and soil type, a specific depth called the unsafe depth was obtained from the analysis results. The structure beneath the soil beyond this depth remains safe. The unsafe depth was found to be increased with the increasing missile velocity.

• Journal of the Korean Institute of Gas
• /
• v.16 no.6
• /
• pp.48-54
• /
• 2012

Building above-ground membrane LNG storage tanks have been recently actively reviewed because they have advantages in ease of large capacity, environmental friendliness, and low possibility of gas leakage of the inner tank (slow increase of leakage speed). In this paper, the safety of membrane LNG storage tanks was ensured through comparative risk assessment of full-containment LNG storage tanks and membrane LNG storage tanks by using Fault Tree Analysis (FTA). Risk assessment results showed that both types of tanks have very similar level of risk except for the membrane storage tanks without additional safety equipments (early model).

• Journal of Radiation Industry
• /
• v.17 no.1
• /
• pp.33-44
• /
• 2023

The deep geological repository of high-level radioactive waste shall be designed to meet the safety objective set in the form of radiation dose or corresponding risk to protect human and the environment from radiation exposure. Engineering feasibility and conformity with the safety objective of the facility conceptual design can be demonstrated by comparing the assessment result using the computational model for scenario(s) describing the radionuclide release and transport from repository to biosphere system. In this study, as the preliminary study for developing the high-level radioactive waste disposal facility in Korea, we reviewed and analyzed the entire list of FEPs and how to handle each FEP from a general point of view, which are selected for the geosphere region in the radiological safety assessment performed for the license application of the KBS-3 type deep geological repository in Finland and Sweden. In Finland, five FEPs (i.e., stress redistribution, creep, stress redistribution, erosion and sedimentation in fractures, methane hydrate formation, and salt exclusion) were excluded or ignored in the radionuclide release and transport assessment. And, in Sweden, six FEPs (i.e., creep, surface weathering and erosion, erosion/sedimentation in fractures, methane hydrate formation, radiation effects (rock and grout), and earth current) were not considered for all time frames and earthquake out of a total of 25 FEPs for the geosphere. Based on these results, an FEP list (draft) for the geosphere was derived, and the relative importance of each item was evaluated for conducting the radiological safety assessment of the domestic deep geological disposal facility. Since most of information on the disposal facility in Korea has not been determined as of now, it is judged that all FEP items presented in Table 3 should be considered for the radiological safety assessment, and the relative importance derived from this study can be used in determining whether to apply each item in the future.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.55 no.2
• /
• pp.145-151
• /
• 2019

The coastal composite fishery has the highest rate of around 30.0% in registered fishing vessels of Korea for the last three years. The risk analysis for the fisher's safety of coastal composite fishing vessels was conducted to serve as a basic data for improving the healthy and safe working environment of fisher using fisher's occupational accidents of the national federation of fisheries cooperatives (NFFC) from 2016 to 2018 (n = 1,105). As a result, the occupational accident occurrence rate of coastal composite fishery was 3.76% in all industries, 7.8 times the rate of that. In addition, death and missing rate was found to have a serious level management to 10.10‱. Among the accidents, 76.0% occurred at sea. The slipping, others and contact with machinery or fishing gear occurred more frequently in order in the frequency of accident occurrence pattern. In the risk assessment using frequency and severity, slipping, contact with machinery and others showed high risk during fishing. The results are expected to contribute to identification and assessment of safety hazard occurred in coastal composite fishing vessels.

• Journal of the Korea Safety Management & Science
• /
• v.26 no.2
• /
• pp.79-86
• /
• 2024

Scientific exploration of how occupational health risks relate with occupational illnesses are essential for mitigating health-related issues in industries. This study analyzed the risk scores obtained by occupational health risk assessments at 3,172 manufacturing companies and examined their effects on occupational illness. Statistical analyses revealed that companies with an occupational health manager (scored 89.1 out of 100) had significantly higher activity scores of health management compared to those without (78.2). However, companies with a history of occupational illness (79.1) or those classified as high-risk industries (85.2) had significantly lower activity scores than their counterparts (81.7, 87.3). In addition, regression analyses using factor analysis showed that latent risk factors such as cardiovascular disease/job stress, health management, and musculoskeletal problem significantly influenced the risk of occupational illness. The activity factors such as health management, work environment management, and regulatory complaisance significant impacted the reduction of occupational illness. The findings of this study can be used to improve the occupational health risk assessment method and utilized in effectively managing occupational risks in industries.

• Smart Structures and Systems
• /
• v.10 no.2
• /
• pp.89-110
• /
• 2012

This study was intended to efficiently perform the probabilistic optimal safety assessment of steel cable-stayed bridges (SCS bridges) using stochastic finite element analysis (SFEA) and expected life-cycle cost (LCC) concept. To that end, advanced probabilistic finite element algorithm (APFEA) which enables to execute the static and dynamic SFEA considering aleatory uncertainties contained in random variable was developed. APFEA is the useful analytical means enabling to conduct the reliability assessment (RA) in a systematic way by considering the result of SFEA based on linearity and nonlinearity of before or after introducing initial tensile force. The appropriateness of APFEA was verified in such a way of comparing the result of SFEA and that of Monte Carlo Simulation (MCS). The probabilistic method was set taking into account of analytical parameters. The dynamic response characteristic by probabilistic method was evaluated using ASFEA, and RA was carried out using analysis results, thereby quantitatively calculating the probabilistic safety. The optimal design was determined based on the expected LCC according to the results of SFEA and RA of alternative designs. Moreover, given the potential epistemic uncertainty contained in safety index, failure probability and minimum LCC, the sensitivity analysis was conducted and as a result, a critical distribution phase was illustrated using a cumulative-percentile.

• Safety and Health at Work
• /
• v.9 no.2
• /
• pp.140-143
• /
• 2018

Background: The Occupational Safety and Health Monitoring and Assessment Tool (OSH-MAT) is a practical instrument that is currently used in the German woodworking and metalworking industries to monitor safety conditions at workplaces. The 12-item scoring system has three subscales rating technical, organizational, and personnel-related conditions in a company. Each item has a rating value ranging from 1 to 9, with higher values indicating higher standard of safety conditions. Methods: The reliability of this instrument was evaluated in a cross-sectional survey among 128 companies and its validity among 30,514 companies. The inter-rater reliability of the instrument was examined independently and simultaneously by two well-trained safety engineers. Agreement between the double ratings was quantified by the intraclass correlation coefficient and absolute agreement of the rating values. The content validity of the OSH-MAT was evaluated by quantifying the association between OSH-MAT values and 5-year average injury rates by Poisson regression analysis adjusted for the size of the companies and industrial sectors. The construct validity of OSH-MAT was examined by principle component factor analysis. Results: Our analysis indicated good to very good inter-rater reliability (intraclass correlation coefficient = 0.64-0.74) of OSH-MAT values with an absolute agreement of between 72% and 81%. Factor analysis identified three component subscales that met exactly the structure theory of this instrument. The Poisson regression analysis demonstrated a statistically significant exposure-response relationship between OSH-MAT values and the 5-year average injury rates. Conclusion: These analyses indicate that OSH-MAT is a valid and reliable instrument that can be used effectively to monitor safety conditions at workplaces.

• Journal of the Korean Society of Safety
• /
• v.31 no.4
• /
• pp.120-125
• /
• 2016

Usually, a risk can be expressed as a product of likelihood and consequence of a hazard factor. Therefore, conventional risk assessment is carried out by frequency analysis and severity analysis, in turns. However, it is well known that intuitive thinking is another excellent way of thinking of human beings. This study aimed to confirm whether there exist any difference in risk assessment results derived by two different procedures - intuitive and analytical. Thus, the present study showed 10 different illustrations to 30 undergraduate students. Their responses were organized as fuzzy membership functions, and summarized as risk assessments, and compared. The results were also verified with the help of statistical hypothesis testing, which showed no significant difference. On the contrary, however, similarity measure used in fuzzy set theory was not credible as anticipated. Many cases failed to satisfy statistical hypothesis even with similarity measure higher than 0.60 so that only a trend could be accepted. In addition, a subject showed a somewhat consistent logical discrepancy in his response, which implied the necessity of sincere analysis in fuzzy formulations.

• Nuclear Engineering and Technology
• /
• v.55 no.3
• /
• pp.981-988
• /
• 2023

A seismic event caused an accident at the Fukushima Nuclear Power Plant, which further resulted in simultaneous accidents at several units. Consequently, this incident has aroused great interest in the safety of nuclear power plants worldwide. A reasonable safety evaluation of such an external event should appropriately consider the correlation between SSCs (structures, systems, and components) and the probability of failure. However, a probabilistic safety assessment in current nuclear industries is performed conservatively, assuming that the failure correlation between SSCs is independent or completely dependent. This is an extreme assumption; a reasonable risk can be calculated, or risk-based decision-making can be conducted only when the appropriate failure correlation between SSCs is considered. Thus, this study analyzed the effect of the failure correlation of SSCs on the safety of the system to realize rational safety assessment and decision-making. Consequently, the impact on the system differs according to the size of the failure probability of the SSCs and the AND and OR conditions.