•This study reviews regional seismic risk assessment across its key modules.•This study also reviews resilience metrics, restoration modeling and planning.•The applicability of existing computational ...workflows is summarized.•Existing challenges and future directions for research advances are highlighted.
Given the devastating losses incurred by past major earthquake events together with the ever-increasing global seismic exposures due to population growth and urbanization, strategic decision-support tools are required to help stakeholders make more contemplated decisions that promote seismic resilience of the built environment. Such decision-support is enabled by regional seismic risk and resilience assessment, which holistically incorporates the various underlying physics processes and uncertainties for quantitative and probabilistic assessment of regional seismic hazard impacts, and has thereby attracted increasing research focus over the past twenty years. As a significant departure from the traditional site-specific assessment, where only an individual structure and site-specific seismic hazard are of interest, such regional-level assessment introduces additional dimensions and complexity. To date, there is a lack of review studies summarizing the related research advancements in seismic risk and resilience assessment from a regional-level perspective in the context of earthquake engineering. This study fills this gap by conducting a systematic review covering: the methodological development of regional seismic risk assessment (RSRiA) across its key modules, including hazard analysis, exposure modeling, fragility assessment, and consequence evaluation, as well as the associated uncertainty quantification and propagation; the development of resilience metrics, restoration modeling and planning in regional seismic resilience assessment (RSReA); and the applicability of existing computational workflows. Insights into the features, applicability, compatibility, and limitations of existing models and tools are provided. This study also highlights the challenges and future directions toward further advancing the research frontiers of RSRiA and RSReA.
•Korea's first dynamic discrete event tree methodology-based tool, DICE, developed.•Validation shows DICE reproduces results of conventional event trees.•DICE simulation highlights potential in ...analyzing success criteria issues.
Although conventional probabilistic safety assessment (PSA) makes a sufficient contribution to evaluating the safety of nuclear facilities, it suffers some limitations in performing optimal assessments close to the actual behavior by reflecting time dependencies in accident management. However, integrated deterministic and probabilistic safety assessment (IDPSA) literally combines two methodologies to enable synchronized evaluation based on physical behavior, system availability of facilities, and operator's response. Dynamic integrated consequence evaluation (DICE) is one of the IDPSA tools developed for this purpose, which is the first achievement in South Korea and supported by a regulatory authority. Based on dynamic discrete event tree (DDET) methodology, DICE consists of a scheduler that supports the exchange of information between modules, including a physical module that computes thermal-hydraulic simulations, a diagnosis module that specifies branching points for safety systems, and a reliability module that provides system availability. This paper deals with numerical validation comparing the conventional deterministic and probabilistic results for a sample scenario with those of DICE, and discusses an application of DICE to support and extend the scope of conventional PSA through a case study. It is expected that DICE emphasizes the compliance with conventional PSA methodologies while providing magnified perception in investigating unforeseen scenarios.
The PSA (Probabilistic Safety Assessment) is presented as a method of comprehensively evaluating the types of accidents that can occur at nuclear power plants. One of the key components to obtain ...technical success was the introduction of event tree analysis, and its strength and weakness has been reviewed and enhanced with the term, for instance, Integrated Deterministic-Probabilistic Safety Assessment (IDPSA) since 1980s. However, the technical and policy maturity of IDPSA appears to have room for improvement: the terminologies need to be arranged internationally, and there are no official standards or guidelines for the method itself. Due to a misperception of IDPSA, there are even concerns that appropriate contribution in risk assessment cannot be made. For this reason, surveys and focus group interviews, sharing development experiences, and the direction of regulation and R&D on IDPSA were conducted targeting PSA experts in Korea. In order to support such process, authors have structured an overview of the development history and technical features of IDPSA. Finally, we will explore the ways to achieve synergy between the deterministic safety analysis and PSA, which may the origin of motivation how to deal with dynamic variability more properly such that an undue risk can be minimized.
Vehicular use of hydrogen is the first attempt to apply hydrogen energy in consumers’ environment in large scale and has raised safety concerns in both public authorities and private bodies such as ...fire services and insurance companies. This paper analyzes typical accident progressions of hydrogen fuel cell vehicles in a road collision accident. Major hydrogen consequences including impinging jet fires and catastrophic tank ruptures are evaluated separately in terms of accident duration and hazard distances. Results show that in a 70 MPa fuel cell car accident, the hazards associated with hydrogen releases would normally last for no more than 1.5 min due to the empty of the tank. For the safety of general public, a perimeter of 100 m is suggested in the accident scene if no hissing sound is heard. However, the perimeter can be reduced to 10 m once the hissing sound of hydrogen release is heard. Furthermore, risks of fatalities, injuries, and damages are all quantified in financial terms to assess the impacts of the accident. Results show that costs of fatalities and injuries contribute most to the overall financial loss, indicating that the insurance premium of fatalities and injuries should be set higher than that of property loss.
•Typical accident progressions of hydrogen car collision on road are analysed.•Duration and hazard distances of impinging jet fires under vehicle are evaluated.•Hazard distances from onboard hydrogen tank catastrophic rupture are suggested.•Risks of fatalities, injuries, and damages are all quantified in financial terms.
Global radionuclide dispersion from Fukushima nuclear accident urged several countries to begin evaluating the radiation effects from neighboring countries. The representative data selection ...simulation is one of the evaluation methods providing practical results with reasonable computational resources. However, it is mostly used in the domestic radiation effect evaluation. This study investigated and modified this simulation method for transboundary radiation effect evaluation. The effects of selected area boundaries, optional weather parameters, and sampling rate, critical parameters in the representative data selection scheme, are sequentially investigated on the calculated results. The evaluation is performed by Nuclear Accident Consequence Analysis Code (NACAC) with hypothetical accidents at Fangchenggang NPP in China. It is revealed that area boundary and optional weather parameter selection insignificantly impact the predicted results, but the sampling rate condition affects the predicted results. Good agreements comprising dispersion characteristics and total effective dose equivalent by simulation using representative and sequential data selections are shown with absolute mean bias error lower than 2.4 × 10
−3
mSv, root mean square error lower than 5.7 × 10
−4
mSv, and correlation coefficient value higher than 9.1 × 10
−1
.
For a long time, research into integrated deterministic-probabilistic safety assessment has been continuously conducted to point out and overcome the limitations of classical ET (event tree)/FT ...(fault tree) based PSA (probabilistic safety assessment). The current paper also attempts to assert the reason why a technical transformation from classical PSA is necessary with a re-interpretation of the categories of risk. In this study, residual risk was classified into interpolating- and extrapolating-censored categories, which represent risks that are difficult to identify through an interpolation or extrapolation of representative scenarios due to potential nonlinearity between hardware and human behaviors intertwined in time and space. The authors hypothesize that such risk can be dealt with only if the classical ETs/FTs are freely relocated, entailing large-scale computation associated with physical models. The functional elements that are favorable to find residual risk were inferred from previous studies. The authors then introduce their under-development enabling techniques, namely DICE (Dynamic Integrated Consequence Evaluation) and DeBATE (Deep learning–Based Accident Trend Estimation). This work can be considered as a preliminary initiative to find the bridging points between deterministic and probabilistic assessments on the pillars of big data technology.
Background and aims: One of the most essential and important steps for improving safety level in existing or designing units is consequence evaluation of hazards such as fire, explosion and ...dispersion of hazardous chemical substances. Due to severe operational conditions, high explosive and flammable gases such as methane and hydrogen, hydrogen production process is causing major industrial accidents of the view life and financial losses. Therefore safety is main concern of hydrogen producers. Methods: First, all hazards and potential scenarios of hydrogen production were identified by applying HAZID Technique, and after collecting the required data, consequence modeling was done by means of professional software PHAST6.54. Death probability of people by means of valid equations of probit was calculated and ultimately, the severity of the consequences was estimated using conventional criteria . Results: The results revealed that, jet fire caused by a full bore rupture in Desulphurization reactor has the highest fatality (26person). The harm effect distance, maximum radiations of this incident were 250 m, 370 kW/m2 respectively. A full bore rupture in Reformer can lead to the most dangerous flash fire. So that people at distance up 130 m from placing leakage and affected area 1505m2 were exposed to concentration of 61120 ppm and all people would be killed. The most dangerous vapor cloud explosion caused by hydrogen purification absorbers, so that distances up to 60m from absorbers location all people would be killed and all process equipments and buildings will be completely destroyed. The safe distance of hydrogen production unit equals to 746 m from its boundary limit. Conclusion: Consequence evaluation is a quantitative and comprehensive method for estimation and evaluation of potential incidents severity of industrial hazardous units. The occurrence of incidents such as fires and explosions has the great life and financial losses in the hydrogen production process, Thus safety of industries nearby hydrogen production and consume must be specifically considered .
•Described hypothetical subjective evaluations of alcohol consequences among mandated college students.•Examined change in hypothetical subjective evaluations across time.•Contrary to hypotheses, ...evaluations became less negative over 3 months.•Baseline experienced consequences did not significantly moderate change in evalautions.•Time-varying experienced consequences had no significant effect on same-timepoint evaluations.
Despite experiencing alcohol-related consequences, college students continue to drink at high rates. Hypothetical evaluations of alcohol-related consequences (i.e., evaluations of where potential/hypothetical consequences lie on a spectrum from extremely positive to extremely negative) may contribute to the maintenance of drinking patterns among students. The purpose of the present study was to describe hypothetical evaluations in a sample of students mandated to an alcohol intervention, examine changes over time, and investigate the influence of both baseline and time-varying experienced consequences. Method: This study was a secondary data analysis from a longitudinal randomized controlled trial. Participants were 474 mandated students (Mage = 18.65; 55.5 % male, 77.6 % White). Students completed an initial baseline assessment of demographics, alcohol use, consequences, and hypothetical evaluations, and 3-month and 9-month follow-up assessments that included hypothetical evaluations and experienced consequences. Results: Hierarchical linear modeling (HLM) analyses revealed significant change in hypothetical evaluations over time such that they became less negative. A piecewise model demonstrated that this change happened between baseline and 3-month, with no additional change between 3-month and 9-month. The experience of consequences at baseline did not significantly moderate changes in either time interval. Time-varying consequences also had no significant effect on same-timepoint hypothetical evaluations. Conclusions: This study is the first to examine changes in hypothetical evaluations over time among mandated college students. Counter to expectations, hypothetical evaluations became less negative at 3-month follow-up. Though preliminary, findings add to the understanding of hypothetical evaluations of alcohol-related consequences.
Sewer pipes health and failure consequences evaluation are vital to ensure the safety of urban sewer networks. Sewer pipes with low health and severe failure consequences should be the primary focus ...of daily maintenance and management for drainage authorities. Conversely, sewer pipes with high health and low failure consequences are temporarily not a primary concern, in order to reduce resource wastage within the constraints of limited economic and time resources. Thus, the scientific analysis of their relationships is deemed essential. This paper applies supply-demand balance theory to analyze the relationship. On the supply side, a health Fuzzy Comprehensive Evaluation model (HFCE) is proposed with weighted hierarchies established. On the demand side, a failure consequences FCE model (FFCE) is established. Each sewer pipe's supply-demand balance score is analyzed using matrix multiplication, highlighting two types of imbalanced pipes and sub-districts. Taking the Liangshui River Basin in Beijing as an example, the results show that the health evaluation can identify the spatial distribution of the health of sewer pipes, with low health levels V and IV accounting for 10.23 % and 4.43 %, respectively. The failure consequences evaluation can evaluate the spatial distribution of the severity of sewer pipe failure consequences, with high failure consequences levels V and IV respectively accounting for 10.97 % and 16.77 %. The supply-demand balance analysis identifies the proportion of the first and second types of imbalanced pipes, respectively 14.24 % and 6.80 %. This method, by analyzing the relationship of health and failure consequences, provides a decision-making basis for drainage authorities to prioritize sewer pipe operation management, repair, and maintenance.
•Supply-demand balance to identify the relationship of health and failure consequences.•DEMATEL optimized AHP calculated weights by considering inter-indicator relationships.•Improved health evaluation via hydraulic metrics in drainage models, enhancing accuracy.•Identifying low(high) health/high(low) failure consequences areas for drainage authorities.
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