A STAMP-Game model for accident analysis in oil and gas industry

Accidents in engineered systems are usually generated by complex socio-technical factors.It is beneficial to investigate the increasing complexity and coupling of these factors from the perspective of system safety.Based on system and control theories,System-Theoretic Accident Model and Processes(STAMP)is a widely recognized approach for accident analysis.In this paper,we propose a STAMP-Game model to analyze accidents in oil and gas storage and transportation systems.Stakeholders in accident analysis by STAMP can be regarded as players of a game.Game theory can,thus,be adopted in accident analysis to depict the competition and cooperation between stakeholders.Subsequently,we established a game model to study the strategies of both supervisory and supervised entities.The obtained results demonstrate that the proposed game model allows for identifying the effectiveness deficiency of the supervisory entity,and the safety and protection altitudes of the supervised entity.The STAMP-Game model can generate quantitative parameters for supporting the behavior and strategy selections of the supervisory and supervised entities.The quantitative data obtained can be used to guide the safety improvement,to reduce the costs of safety regulation violation and accident risk.

Preliminary safety analysis for heavy water-moderated molten salt reactor

The heavy water-moderated molten salt reactor(HWMSR)is a newly proposed reactor concept,in which heavy water is adopted as the moderator and molten salt dissolved with fissile and fertile elements is used as the fuel.Issues arising from graphite in traditional molten salt reactors,including the positive temperature coefficient and management of highly radio-active spent graphite waste,can be addressed using the HWMSR.Until now,research on the HWMSR has been centered on the core design and nuclear fuel cycle to explore the viability of the HWMSR and its advantages in fuel utilization.However,the core safety of the HWMSR has not been extensively studied.Therefore,we evaluate typical accidents in a small modular HWMSR,including fuel salt inlet temperature overcooling and overheating accidents,fuel salt inlet flow rate decrease,heavy water inlet temperature overcooling accidents,and heavy water inlet mass flow rate decrease accidents,based on a neutronics and thermal-hydraulics coupled code.The results demonstrated that the core maintained safety during the investigated accidents.

ANALYSISOFOPERATIONALCAUSESOFAIRPLANETAKEOFFACCIDENTS

The possibility and causes of flight accidents by operational error/deviation in takeoff are analyzed in this paper. The following three stages are each described individually: before liftoff, near liftoff and initial climb. Relations of accident/incident causal factors by operational error with intrinsical flight mechanics are discussed.

Six-hierarchy model of accident analysis and its application in coal mine accidents

Accident analysis models play a significant role in accident investigation and analysis.Most traditional models,usually based on a chain of events,have serious limitations when used for complex systems,especially for coal mine accident.HFACS is a widely accepted accident cause model with complex structure and content.Based on HFACS and accident investigation need in China,a new systemic accident analysis method“Six-hierarchy model”is proposed.And the index database of accident causal factors at each hierarchy of coal mine accidents is established.This model provides clear guidance for the prevention of accidents from six levels,which helps to the targeted rectification after accidents and the improvement of safety management level.The source,ap-plication scope,advantages and disadvantages of HFACS and six-hierarchy model are compared.The“2.14”gas explosion accident in Sunjiawan coal mine is analyzed by using HFACS and six-hierarchy model and the safety management suggestions are put forward.The study shows that the Six-hierarchy model provides a clear guide for the prevention of accidents from six levels.And it benefits the targeted rectification after accidents and the continuous improvement of safety management.

A data mining approach to characterize road accident locations

Data mining has been proven as a reliable technique to analyze road accidents and provide productive results. Most of the road accident data analysis use data mining techniques, focusing on identifying factors that affect the severity of an accident. However, any damage resulting from road accidents is always unacceptable in terms of health, property damage and other economic factors. Sometimes, it is found that road accident occurrences are more frequent at certain specific locations. The analysis of these locations can help in identifying certain road accident features that make a road accident to occur frequently in these locations. Association rule mining is one of the popular data mining techniques that identify the correlation in various attributes of road accident. In this paper, we first applied k-means algorithm to group the accident locations into three categories, high-frequency, moderate-frequency and low-frequency accident locations. k-means algorithm takes accident frequency count as a parameter to cluster the locations. Then we used association rule mining to characterize these locations. The rules revealed different factors associated with road accidents at different locations with varying accident frequencies. Theassociation rules for high-frequency accident location disclosed that intersections on highways are more dangerous for every type of accidents. High-frequency accident locations mostly involved two-wheeler accidents at hilly regions. In moderate-frequency accident locations, colonies near local roads and intersection on highway roads are found dangerous for pedestrian hit accidents. Low-frequency accident locations are scattered throughout the district and the most of the accidents at these locations were not critical. Although the data set was limited to some selected attributes, our approach extracted some useful hidden information from the data which can be utilized to take some preventive efforts in these locations.

Hazard Mitigation through a Systemic Model of Accident to a Socio-Technical System： A Case Study

This paper presents the STAMP （system-theoretic accident modeling and processes） accident model, based on systems theory, and describes its application in the context of risk prevention related to the remediation of contaminated sediments. The implementation of the model is described, and results are presented both in methodological and technical terms. The goal of this article is to emphasize the need of new approaches to take into account hazards and accidents within socio-technical systems.

Analysis and Referential Significance of a Breakdown Accident of the Main Feed Water Pump in a 350 MW Supercritical CFB Boiler

Controversies still exist over the necessity of equipping with an emergency water supply system in the supercritical circulating fluidized bed/CFB unit.To resolve the dispute,research on the safety of the heating surfaces in the supercritical CFB boiler during the electricity failure accident under the assumption of not putting the emergency water supply system into use must be conducted.However,due to the low incidence rate of this accident,no relevant data have been reported yet.To provide useful data for the related research,a breakdown accident of the main feed water pump that happened in a 350 MW supercritical CFB boiler was introduced in this work.The analysis of the physical processes in both the furnace and water side of the boiler during this accident was performed.Then the discussion on the similarities and discrepancies between the two accidents was carried out.It was found out that with appropriate handling,the data collected in two periods of the breakdown accident of the main feed water pump can provide a reference for the verification of the prediction model of the electricity failure accident.Finally,a preliminary prediction model was established as the first step of the verification work.

Analysis of traffic safety in airport aircraft activity areas based on bayesian networks and fault trees

To assess road traffic safety risk in civil aviation airports and develop effective accident prevention measures,this study proposed a risk assessment method based on accident tree and Bayesian network for airport aircraft activity areas.It identified influencing factors in the aircraft activity area from the perspectives of person-vehicle-road-environment-management and analyzed their relationships.The Bayesian network was utilized to determine initial probabilities for each influencing factor.Findings indicated a relatively high overall safety level in the airport's road traffic system.Accident trees were employed to qualitatively and quantitatively analyze common human-vehicle accident patterns.The initial probabilities obtained from the Bayesian network served as basic event probabilities in the accident tree to determine the occurrence probability of the top event.Taking a 4F airport in China as an example,accident cause analysis identified five important risk sources in human-vehicle accidents,including blind spots for special vehicles,illegal driving by drivers,pedestrians violating regulations,passengers entering restricted areas,and blind spots at intersections.Corresponding safety management measures were formulated.The study concluded that the integration of Bayesian networks and accident trees effectively determines accident probabilities and offers specific solutions,thus playing a crucial role in enhancing road traffic safety management within aviation airports.

Effect of helmet-wearing regulation on electric-bike riders:a case study of two cities in China

Objectives:Electric bikes(e-bikes)are widely used for commuting and delivery in China.With the rapid increase in e-bikes on the road,related accidents have become crucial issues threatening the public.This research aims to explore the protective effect of helmet-wearing regulation and to investigate some factors influencing head injury with reference to two case cities in China,obtaining information to protect e-bike riders.Methods:The traffic police-reported crash data cover the periods before and after the implementation of helmet-wearing regulations in Taizhou(with data from 2017 to 2019)and Nanning(with data in 2020)of China.Preliminary statistical analysis,logistic regression and chi-square test with a Bonferroni correction were applied in the research.Results:A lack of helmets was common among victims in the context of a high helmet-wearing rate among general e-bike riders in Taizhou,indicating that fatality could be avoided to some extent by wearing helmets.Specifically,helmet wearing could reduce the probability of suffering fatal head injury by 6.4%.After the regulation implementation in Taizhou,the proportion of fatal head injuries decreased from 89%to 79%,remaining at a high level,which indicates that other measures in addition to helmet-wearing regulations should be taken.According to the results from Nanning,mandatory regulation worked more effectively than encouraged regulation in terms of reducing head injury.Conclusions:Mandatory helmet-wearing regulations are highly recommended to policymakers to reduce head injury among e-bike riders.Measures in addition to helmet-wearing regulation,e.g.enhancing law-abiding awareness and improving road infrastructure,should be considered to further protect e-bike riders.

Promoting Metro Operation Safety by Exploring Metro Operation Accident Network

Understanding the causation of accidents is essential to promote metro operation safety.In terms of 243 reported metro operation accident cases in China, a directed weighted network was constructed based on complex network theory, where nodes and directed edges denotes factors and event chains respectively. To reveal the key causal factors, the topological characteristics of metro operation accident network(MOAN) were analyzed from both global and local views. The results show that facility-type factors are more closely related to the occurrence of the accidents from the perspectives of average path length and cascading effects. Accident types like train delay and train suspension are the great risk recipients. Key causal factors with large out-degree, out-strength, betweenness centrality and cluster coefficient, such as communication and signal failure, vehicle failure and piling into the train should be noticed. The research framework proposed in the paper is not only applicable to China’s metro operation system, but also appropriate for other transportation system safety studies.

Experience gained in analyzing severe accidents for WWER RP using CC SOCRAT

The current Russian regulatory documents on the safety of nuclear power plant(NPP)specify the requirements regarding design basis accidents(DBAs)and beyond design basis accidents(BDBAs),including severe accidents(SAs)with core meltdown,in NPP design(NP-001-15,NP-082-07,and others).For a rigorous calculational justification of BDBAs and SAs,it is necessary to develop an integral CC that will be in line with the requirements of regulatory documents on verification and certification(RD-03-33-2008,RD-03-34-2000)and will allow for determining the amount of data required to provide information within the scope stipulated by the requirements for the structure of the safety analysis report(SAR)(NP-006-16).The system of codes for realistic analysis of severe accidents(SOCRAT)(formerly,thermohydraulics(RATEG)/coupled physical and chemical processes(SVECHA)/behavior of core materials relocated into the reactor lower plenum(HEFEST))was developed in Russia to analyze a wide range of SAs at NPP with water-cooled water-moderated power-generating reactor(WWER)at all stages of the accident.Enhancements to the code and broadening of its applicability are continually being pursued by the code developers(Nuclear Safety Institute of the Russian Academy of Sciences(IBRAE RAN))with OKB Gidropress JSC and other organizations.Currently,the SOCRAT/В1 code can be used as a base tool to obtain realistic estimates for all parameters important for computational justification of the reactor plant(RP)safety at the in-vessel stage of SAs with fuel melting.To perform analyses using CC SOCRAT/В1,the experience gained during execution of thermohydraulic codes is applied,which allows for minimizing the uncertainties in the results at the early stage of an accident scenario.This study presents the results of the work performed in 2010–2020 in OKB Gidropress JSC using the CC SOCRAT/В1.Approaches have been considered to develop calculational models and analyze SAs using CC SOCRAT.This process,which is clearly structured in OKB Gidropress JSC,provides a noticeable reduction in human involvement,and reduces the probability of erroneous results.This study represents the principal results of the work performed in 2010–2020 in OKB Gidropress JSC using the CC SOCRAT,as well as a list of the tasks planned for 2021–2023.CC SOCRAT/B1 is used as the base thermohydraulic SAs code.