Conceptual Strategy for Mitigating the Risk of Hydrogen as an Internal Hazard in Case of Severe Accidents at Nuclear Power Plant Considering Existing Risks and Uncertainties Associated with the Use of Traditional Strategies

Hydrogen challenge mitigation stands as one of the main objectives in the management of severe accidents at Nuclear Power Plants (NPPs). Key strategies for hydrogen control include atmospheric inertization and hydrogen removal with Passive Autocatalytic Recombiners (PARs) being a commonly accepted approach. However, an examination of PAR operation specificity reveals potential inefficiencies and reliability issues in certain severe accident scenarios. Moreover, during the in-vessel stage of severe accident development, in some severe accident scenarios PARs can unexpectedly become a source of hydrogen detonation. The effectiveness of hydrogen removal systems depends on various factors, including the chosen strategies, severe accident scenarios, reactor building design, and other influencing factors. Consequently, a comprehensive hydrogen mitigation strategy must effectively incorporate a combination of strategies rather than be based on one strategy, taking into consideration the probabilistic risks and uncertainties associated with the implementation of PARs or other traditional methods. In response to these considerations, within the framework of this research it has been suggested a conceptual strategy to mitigate the hydrogen challenge during the in-vessel stage of severe accident development.

Analysis of the Necessity of Stellate Ganglion Block after Anesthesia to Reduce the Risk of Cardiovascular Accidents in Coronary Heart Disease

Objective:To adjust the sympathetic nervous system through preoperative ultrasound-guided stellate ganglion block and to explore and analyze the situation and necessity of postanesthesia stellate ganglion block to reduce the risk of cardiovascular accidents in coronary heart disease.Methods:80 patients with cardiovascular risk factors in Songshan Hospital of Chifeng were selected,and the time span would cover from October 2022 to June 2024,with 80 cases of elective surgery and combined coronary heart disease.They will be randomly divided into blocked groups and conventional groups,40 cases each.Conventional block was performed after anesthesia in patients in the conventional group,and planetary ganglion block was performed after anesthesia in patients in the blocked group.The cardiovascular responses of patients in the two groups were observed,and the number of intraoperative cardiovascular active drugs and the occurrence of cardiovascular adverse events were recorded in patients in the two groups.Results:Analysis of the mean arterial pressure(MAP)and heart rate(HR)values of the two groups of patients at the time points before anesthesia(T0),the moment of tracheal intubation(T1),the moment of surgical skin cutting(T2),the end of the operation(T3),and the 6h postoperative period(T4)showed that the MAP and HR of the blocked group were lower than those of the conventional group at the time points of T1 to T4,and the differences in MAP and HR values of the two groups in different time points compared with the T0 time point were statistically significant(P<0.05)and the differences in cardiovascular response(P<0.05)were statistically significant(P<0.05).significance(P<0.05).The number of intraoperative cardiovascular active drugs used in the blocked group was shorter than that in the conventional group,and the incidence of cardiovascular adverse events was lower than that in the conventional group,with a statistically significant difference(P<0.05).Conclusion:By implementing preoperative ultrasound-guided stellate ganglion block in patients with cardiovascular risk factors,the frequency and degree of coronary heart disease symptoms will be reduced,thus reducing the risk of patients,which is worth promoting.

Informational uncertainties of risk assessment about accidents of chemicals

An analysis system of informational uncertainties for accidental risk assessment of chemicals is introduced. Statistical test methods and fuzzy sets method can do the quantitative analysis of the input parameters. The uncerainties of the model can be used by quantitative compared method for the leakage accidents of chemicals. The estimation of the leaking time is important for discussing accidental source term. The uncertain analyses of the release accident for pipeline gas (CO) liquid chlorine and liquid propane gas (LPG) have been discussed.

Analysis of the Tragedy of Vila Socóin Cubatão (São Paulo, Brazil) Using the Haddon Matrix: A Comprehensive Examination of Socio-Environmental Factors and Risk Mitigation Strategies

The tragedy of Vila Socó epitomizes the socio-environmental repercussions of rapid industrialization in Cubatão. Beginning in the 1940s with the construction of the Anchieta highway, the city experienced an influx of migrants drawn by burgeoning industries, leading to unplanned urban growth and the emergence of vulnerable communities like Vila Socó. This article examines the interconnected factors—such as demographic shifts, inadequate planning, and regulatory oversight—that culminated in the devastating fire of 1984, claiming numerous lives and highlighting systemic failures. Utilizing the Haddon Matrix, this study dissects the Vila Socó incident, emphasizing the roles of human error, infrastructure integrity, and socio-economic disparities in disaster causation. By contextualizing the tragedy within Cubatão’s industrial trajectory, it underscores the urgent need for comprehensive risk assessment and proactive mitigation strategies in rapidly developing regions globally. Beyond its immediate focus, this work offers broader insights into the dynamics of industrial disasters and their socio-economic implications. As pipelines continue to play a vital role in global energy infrastructure, the lessons drawn from Vila Socó’s tragedy resonate deeply, emphasizing the imperative of robust safety protocols and accountable governance to prevent similar catastrophes in the future.

Analyzing Pedestrian Fatality Risk in Accidents at Mid-Blocks

Objective: Pedestrian safety is considered as one of the greatest concerns, especially for developing countries. In the year of 2015, about 48% pedestrian accidents with 56% fatalities occurred at mid-blocks in Beijing. Since the high frequency and fatality risk, this study focused on pedestrian accidents taking place at mid-blocks and aimed at identifying significant factors. Methods: Based on total 10,948 crash records, a binary logit model was established to explore the impact of various factors on the probability of pedestrian’s death. Furthermore, first-degree interaction effects were introduced into the basic model. The Hosmer-Lemeshow goodness-of-fit test was used to assess the model performance. Odds ratio was calculated for categorical variables to compare significant accident conditions with the conference level. Variables within consideration in this study included weather, area type, road type, speed limit, pedestrian location, lighting condition, vehicle type, pedestrian gender and pedestrian age. Results: The calibration results of the model show that the increased fatality chances of an accident at mid-blocks are associated with normal weather, rural area, two-way divided road, crossing elsewhere in carriageway, darkness (especially for no street lighting), light vehicle, large vehicle and male pedestrian. With road speed limit increasing by 10 km/h, the probability of death accordingly increases by 46%. Older victims have higher chances of being killed in a crash. Moreover, three interaction effects are found significant: rural area and two-way divided, rural area and crossing elsewhere as well as speed limit and pedestrian age. Conclusions: This study has analyzed police accident data and identified factors significant to the death probability of pedestrians in accidents occurred at mid-blocks. Recommendations and improving measures were proposed correspondingly. Behaviors of different road users at mid-blocks should be taken into account in the future research.

Typology and Risk Factors of Public Road Accidents in Kinshasa with Its Two Peripheral Areas (Mongata and Kasangulu) from March to May 2017

Introduction: Road traffic put people at risks and needs health education to avoid accidents and deaths. This article aimed to build up a typology of public road accidents (public road accidents) and risk factors associated with in the provincial city of Kinshasa and its peripheral cities (Kasangulu and Mongata), to identify the profiles of the vehicles and people involved in these public road accidents. Method: We conducted a prospective eco-analytical study on a stratified random sample whose size was determined by the Fischer formula. Results: Overall, from March to May 2017, we witnessed an incidence of public road accidents cases ranging from 139 public road accidents cases in the city province of Kinshasa and its two peripheral areas: road axes of high concentration: Rte Blvd Lumumba-Airport;Rte Poids Lourd-Pont Matete, the axes of medium concentration: Rte N21-IMBU, Rte Blvd 30 juin-socimat;Rte Matadi-Kasangulu toll;Rte Université-Intendance, Rte By Pass-triangle Maman Mobutu-Kintambo (Rte-Matadi)-Toll/lère virage-Triangle Maman Mobutu and those of low concentration were: Rte du tourisme/Mimoza-Mbudi;Rte Matadi-Terrain Siwabanza. Conclusion: In these areas, public road accidents are a real public health problem that deserves sustained attention from all and especially from decision makers. Interventions must concern the HVE accident complex.

Risk factors and predictive model of cerebral edema after road traffic accidents-related traumatic brain injury

Purpose:Cerebral edema(CE)is the main secondary injury following traumatic brain injury(TBI)caused by road traffic accidents(RTAs).It is challenging to be predicted timely.In this study,we aimed to develop a prediction model for CE by identifying its risk factors and comparing the timing of edema occurrence in TBI patients with varying levels of injuries.Methods:This case-control study included 218 patients with TBI caused by RTAs.The cohort was divided into CE and non-CE groups,according to CT results within 7 days.Demographic data,imaging data,and clinical data were collected and analyzed.Quantitative variables that follow normal distribution were presented as mean±standard deviation,those that do not follow normal distribution were presented as median(Q1,Q3).Categorical variables were expressed as percentages.The Chi-square test and logistic regression analysis were used to identify risk factors for CE.Logistic curve fitting was performed to predict the time to secondary CE in TBI patients with different levels of injuries.The efficacy of the model was evaluated using the receiver operator characteristic curve.Results:According to the study,almost half(47.3%)of the patients were found to have CE.The risk factors associated with CE were bilateral frontal lobe contusion,unilateral frontal lobe contusion,cerebral contusion,subarachnoid hemorrhage,and abbreviated injury scale(AIS).The odds ratio values for these factors were 7.27(95%confidence interval(CI):2.08-25.42,p=0.002),2.85(95%CI:1.11-7.31,p=0.030),2.62(95%CI:1.12-6.13,p=0.027),2.44(95%CI:1.25-4.76,p=0.009),and 1.5(95%CI:1.10-2.04,p=0.009),respectively.We also observed that patients with mild/moderate TBI(AIS≤3)had a 50%probability of developing CE 19.7 h after injury(χ^(2)=13.82,adjusted R2=0.51),while patients with severe TBI(AIS>3)developed CE after 12.5 h(χ^(2)=18.48,adjusted R2=0.54).Finally,we conducted a receiver operator characteristic curve analysis of CE time,which showed an area under the curve of 0.744 and 0.672 for severe and mild/moderate TBI,respectively.Conclusion:Our study found that the onset of CE in individuals with TBI resulting from RTAs was correlated with the severity of the injury.Specifically,those with more severe injuries experienced an earlier onset of CE.These findings suggest that there is a critical time window for clinical intervention in cases of CE secondary to TBI.

Risk forecasting and evaluating model of Environmental pollution accident

Environmental risk(ER) factors come from ER source and they are controlled by the primary control mechanism(PCM) of environmental risk, due to the self failures or the effects of external environment risk trigger mechanism, the PCM could not work regularly any more, then, the ER factors will release environmental space, and an ER field is formed up. The forming of ER field does not mean that any environmental pollution accident(EPA) will break out; only the ER receptors are exposed in the ER field and damaged seriously, the potential ER really turns into an actual EPA. Researching on the general laws of evolving from environmental risk to EPA, this paper bring forwards a relevant concept model of risk forecasting and evaluating of EPA. This model provides some scientific methods for risk evaluation, prevention and emergency response of EPA. This model not only enriches and develops the theory system of environment safety and emergency response, but also acts as an instruction for public safety, enterprise's safety management and emergency response of the accident.

Increasing Road Traffic Throughput through Dynamic Traffic Accident Risk Mitigation

The introduction of vehicular ad-hoc networks (VANETs) leads to the possibility to re-evaluate many traditional functions and views of road traffic networks. The ability for vehicles and infrastructure to communicate and collaborate will enable many novel solutions for problems as diverse as collision avoidance and traffic management with the view of reducing traffic congestion, increasing the effectiveness of logistics systems etc. In this paper we introduce a novel framework that utilises VANET information to share information about risk factors among road occupants and infrastructure. We introduce the concept of risk limits as a means of traffic accident risk mitigation, whereby vehicles need to adjust their behaviour to maintain a given level of risk. We discuss determination of risk values and detail this process using the NSW traffic accident database. We show how the effects on risk of particular vehicular behaviours such as speed and headway can be calculated and use these results to modify vehicle behaviour in real time to maintain a predefined risk limit. Experiments are carried out using the Paramics Microsimulator. Our results show that it is possible to reduce the accident rate among vehicles while at the same time increasing road network throughput by exploiting the variation in risk between vehicles.

Risk Management of the Escalator Overturned Accident

Escalator is a vehicle related to people's daily life closely while it incurs safety problems frequently.Therefore,developing a new methodology for escalator safety assessment is very important.In this paper,the related suitable risk analysis models for the escalator overturned accident were proposed on different risk management stages.Firstly,field of the escalator was surveyed and information was collected to identify the danger sources.Secondly,a safety assessment process was done for escalator risk evaluation.Then the dangerous levels were devised based on the LEC evaluation method.According to the results,targeted management measures suggestions and effective safety strategy were proposed finally to solve the escalator overturned problems.The practice has proven that the safety assessment method in this paper is convenient,efficient and effective,which helps to improve the elevators safety level in China and supports the government management.

Needs and Challenges of Nigeria Petroleum Industry in Assessing Process Safety Cumulative Risk

A cross-sectional exploratory assessment of the needs and challenges of petroleum industry in Nigeria, in assessing process safety cumulative risk for major accidents prevention was investigated. A purposive cum random sampling technique was used in this study, among selected petroleum companies operating in Nigeria. Survey questionnaires were received from 216 participants made up of asset integrity engineers/operators, process safety experts, production safety professionals in the petroleum industry in Nigeria. Data analyses were carried out to cover descriptive and inferential statistics. Overall, the study recognized that assessing process safety cumulative risk is not a simple process due largely to the changing nature of safety critical barriers degradation data. The study result showed four main challenges faced by petroleum industries in Nigeria, in assessing process safety cumulative risk: 1) the study showed that 94% of the respondents agreed that there is limited accessibility to safety critical barriers degradation data (little automation). Also 2) 94% of the respondents accounted for poor knowledge of process safety cumulative risk is and agreed it to be of low rating. The result further showed that 3) 90% of the respondents demonstrated that there are no guidance and procedures in assessing process safety cumulative risk and finally 4) 92% of the respondents reported that there is no real-time risk visualization model/ tool. Addressing these issues and challenges by the petroleum industries in the study area, will lead to successful assessment of process safety cumulative risk, thereby reducing the risk of major accidents.

Stroke (Cerebrovascular Accident): Epidemiological, Clinical and Evolving Aspects in the Internal Medicine Department of the Public Health Establishment 1 (EPS1) of Tivaouane

Introduction: The frequency, severity, cost of treatment, morbidity and mortality of stroke make it a real public health problem. In industrialized countries, strokes are the leading cause of physical disability in adults, the second leading cause of dementia (after Alzheimer’s disease), and the third leading cause of death (after cancer and cardiovascular disease). It’s also a major cause of depression. The objective of our study was to describe the epidemiological, clinical and evolutionary aspects of stroke in the internal medicine department of Tivaouane Hospital. Material and Method: This is a retrospective study carried out from January 1, 2015 to December 31, 2018 on the files of patients hospitalized for stroke in the medical department of the EPS1 in Tivaouane. We took into account all the patients who had a brain CT (computed tomography) scan. We collected data related to socio-demographic characteristics, history, risk factors, reasons for admission, clinical signs, paraclinical examinations, as well as evolution. Results: Out of 1999 patients, 206 files of patients with stroke were collected, i.e. a proportion of 10.3%. Our study population had a mean age of 65.53 years [16 - 97 years]. We noted a clear predominance of women (50.5%). The majority of the population came from the outskirts of Tivaouane (56.7%). Risk factors for stroke were dominated by hypertension (90.3%), dyslipidemia (19.4%), previous stroke (18.9%), and diabetes (16%). The clinical signs were dominated by a motor deficit (94.1%), speech disorders (67.4%) and consciousness disorders (47%). Ischemic strokes were predominant (65%) over hemorrhagic strokes (34.5%). The outcome was generally unfavorable with 14.6% total recovery, 58.7% recovery with sequelae and a case fatality of 26.7%. Conclusion: It emerges from this study that strokes still remain a real public health problem. Knowledge of populations of risk factors as well as their proper management is fundamental in primary prevention strategies, the only guarantee for a reduction in the still very high morbidity and mortality of this disease.

Severe accident risks from external events

This paper reviews the early development of design requirements for seismic events in USA early developing nuclear electric generating fleet. Notable safety studies,including WASH-1400,Sandia Siting Study and the NUREG1150 probabilistic risk study,are briefly reviewed in terms of their relevance to extreme accidents arising from seismic and other severe accident initiators. Specific characteristic about the nature of severe accidents in nuclear power plant (NPP) are reviewed along with present day state-of-art analysis methodologies (methods for estimation of leakages and consequences of releases (MELCOR) and MELCOR accident consequence code system (MACCS)) that are used to evaluate severe accidents and to optimize mitigative and protective actions against such accidents. It is the aim of this paper to make nuclear operating nations aware of the risks that accompany a much needed energy resource and to identify some of the tools,techniques and landmark safety studies that serve to make the technology safer and to maintain vigilance and adequate safety culture for the responsible management of this valuable but unforgiving technology.

基于组合赋权三维云评估技术的深部煤矿顶板事故风险分析

为了更好地对深部煤矿顶板事故展开风险评价,提出了组合赋权三维云评估技术。基于事故统计及事故致因理论,对深部煤矿顶板事故风险指标体系展开研究,采用博弈论对改进层次分析法(Analytic Hierarchy Process,AHP)和熵权法进行博弈分析,以实现风险指标的组合赋权,通过构建三维云模型,对深部煤矿顶板事故危险性进行可视化分析。结果表明:包括行为、技术、设备、环境、管理5大风险因素在内的一级指标并其下20个二级风险指标是深部煤矿顶板事故风险评价指标体系的主体内容,且以环境风险权重最大;由三维云评估技术分析可知,平煤九矿的顶板事故风险级别为Ⅲ级,即修复后可接受,与该矿生产实际情况相符。组合赋权三维云评估技术的提出有助于完善深部煤矿顶板事故风险评价方法,可应用于工程实践。

基于装置运行平稳性的石油化工安全管理策略研究

为了找出并评价石化装置支配性风险因素,实现安全生产风险源头控制和管理,满足石化装置安全生产风险控制的高效性要求,通过建立石化装置事故风险影响模型,运用决策试验与评估实验室方法(DEMATEL)从“现代事故因果连锁理论”视角分析发现人、机(物)等风险因素都受管理因素支配。进而,基于工艺稳定性、工艺稳定性修正、非计划停工3个指标建立石化装置平稳性模型,对装置运行平稳率进行追踪统计,并通过实例对该模型进行了分析和验证。结果表明:该石化装置运行平稳性模型可以量化追踪事故风险支配性因素的控制效果,可展示石化装置不同阶段下的风险特点,可作为装置事故风险预警指标和安全管理绩效指标,可提高装置的安全管理水平。

砖木结构古建筑火灾风险影响因子评估研究

提出模糊DEMATEL-ISM的方法,在建立古建筑火灾评价指标体系的基础上,对归属于4大类风险因素的25个潜在风险因子进行关联性分析,得出因子的因果属性及因子间的逻辑层次结构关系,从而对古建筑火灾风险进行评估。利用模糊DEMATEL-ISM法对华阴市西岳庙灏灵殿进行实例分析,结果表明:疏散与扑救条件、电器设备隐患的原因度较大,需要对其予以控制;耐火等级、火灾荷载的结果度大,为事故发生的主要原因;疏散与扑救条件、易燃易爆危险品、电器设备隐患、安全责任制、灭火应急预案和演练为古建筑火灾事故的关键风险因子,可为古建筑火灾风险管控工作提供相应参考。

基于数据驱动贝叶斯网络的化工事故风险分析

为减少化工厂风险分析中的主观干预,基于关联规则和贝叶斯网络构建1种数据驱动风险分析模型。该模型涵盖3个任务项,分别为数据集项、关联规则驱动项和贝叶斯网络风险评估项。首先,收集事故报告和事故因素构建事故数据库;其次,将事故数据导入Apriori算法,并根据关联规则的因素相关性确定贝叶斯网络和条件概率表结构;然后,基于事故因素出现频率计算先验概率和条件概率,并采用Fussel-Vesely计算事故因素的敏感度;最后,收集94起危险化学品中毒窒息事故实例,运用数据驱动风险分析模型评估事故因素的影响大小。研究结果可为减少和避免化工事故提供一定参考,有助于提高相关企业的整体安全水平。

考虑乡镇集市影响的穿村镇公路事故风险因素辨识

为了改善乡镇集市与穿村镇公路耦合区域的交通安全,以云南省某二级公路穿村镇路段为研究对象,依据乡镇居民可承受出行距离与集市最大交易半径,界定集市核心区与集市辐射区,选取人、车、路、环境、管理及事故形态6个维度的29个风险因素,采用基于关联规则的风险因素辨识模型构建穿村镇公路事故风险因素网络,分析网络拓扑结构特征获取事故关键风险因素。结果表明:集日穿村镇公路事故时空集聚特征显著,且集市核心区交通冲突更为严重,伤人事故概率为57.99%,是事故的主要风险因素,对事故风险传播具有主导作用;直穿村镇路段交通标志缺失与缓坡路段会车不当分别是财产损失事故与伤人事故的直接风险因素;整体上,驾驶员因素平均聚类系数最大,易产生连锁反应,在集市核心区涉及驾驶员会车不当和未按规定让行时,伤人事故概率分别增加23.71%和21.07%。