Uncertainty and sensitivity analysis of in-vessel phenomena under severe accident mitigation strategy based on ISAA-SAUP program

The phenomenology involved in severe accidents in nuclear reactors is highly complex.Currently,integrated analysis programs used for severe accident analysis heavily rely on custom empirical parameters,which introduce considerable uncertainty.Therefore,in recent years,the field of severe accidents has shifted its focus toward applying uncertainty analysis methods to quantify uncertainty in safety assessment programs,known as“best estimate plus uncertainty(BEPU).”This approach aids in enhancing our comprehension of these programs and their further development and improvement.This study concentrates on a third-generation pressurized water reactor equipped with advanced active and passive mitigation strategies.Through an Integrated Severe Accident Analysis Program(ISAA),numerical modeling and uncertainty analysis were conducted on severe accidents resulting from large break loss of coolant accidents.Seventeen uncertainty parameters of the ISAA program were meticulously screened.Using Wilks'formula,the developed uncertainty program code,SAUP,was employed to carry out Latin hypercube sampling,while ISAA was employed to execute batch calculations.Statistical analysis was then conducted on two figures of merit,namely hydrogen generation and the release of fission products within the pressure vessel.Uncertainty calculations revealed that hydrogen production and the fraction of fission product released exhibited a normal distribution,ranging from 182.784 to 330.664 kg and from 15.6 to 84.3%,respectively.The ratio of hydrogen production to reactor thermal power fell within the range of 0.0578–0.105.A sensitivity analysis was performed for uncertain input parameters,revealing significant correlations between the failure temperature of the cladding oxide layer,maximum melt flow rate,size of the particulate debris,and porosity of the debris with both hydrogen generation and the release of fission products.

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.

Elaboration of Explanatory Factors of Accidents in Cameroon by Factorial Correspondence Analysis

The aim of this paper is to examine the causes of road accidents in Cameroon. The Douala-Yaoundé highway was chosen as the case of study. Available field data recorded from the year 2006 to 2011, have enabled the analysis of each accident. The method used here is the factorial correspondence analysis;which aims to bring in a small number of dimensions, most of the initial information, focusing not on the absolute values, but the correspondence between the variables, that is to say the relative values. From this analysis, it appears that, of the 906 accidents recorded during this period, top five causes account for nearly 83% of the information provided by the set of variables on the occurrence of road accidents. These causes are: driver inattention, lack of control, over speeding, improper overtaking and tire puncture. These results require involvement in the construction of road safety policies through training, sensitization and adequate repressions as well as administrative reforms and research policy in road safety.

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.

Assessing Factors for Occurrence of Road Accidents in Tanzania Using Panel Data Analysis: Road Safety Perspective

This study assessed critical factors for road traffic accidents and associated mitigation to reduce the accidents by the year 2030. The study was guided by research questions, what are the major causatives of road accidents and how to mitigate the problem. The study used secondary data collected from the repository database of traffic police at the division of Tanzania Road Safety Squad. Data were collected at the events of accident occurrences and reported annually by regions. Panel data analysis was used to allow for controlling variables which cannot be observed over time and across areas such as regions. Pooled Poisson model, fixed effect and random effect Poisson model was applied to assess factors for road traffic accidents. Fixed effect model was the best model with a reasonably good fit. Results indicated that all predictors are significant under fixed effect Poisson model with a p-value less than 0.05 but Passengers and Railway crossing road was found insignificant and dropped in the final model. Laws and regulatory frameworks should be formulated and enforced promptly for Tanzania may reach the target of 2nd decade of action for roads safety 2021-2030.

Analysis of the Relationship between the Number of Traffic Accidents and the Traffic Flow &Section Location in Extra Long Tunnel

In order to study the influence of the traffic characteristics on traffic accidents in extra long tunnel, the main measurement indicators of traffic flow during the time of traffic accidents are matched with the accident information to form a data set of the number of traffic accidents and the hourly traffic flow of the accident. Vehicle ratio and the number of accidents are mainly used as the characteristic indicators of traffic flow. At the same time, the longitudinal distribution law of the average speed of traffic flow and the number of traffic accidents in the extra long tunnel is studied. Based on the superposition principle, the extra long tunnel is divided into 5 traffic safety zones. This paper analyzes the distribution of time, morphology, cause of accident, and other characteristics in different traffic safety zones, finding that the shape of traffic accidents in extra long tunnel is mainly rear-end collisions. Improper operation and illegal lane changes are the main causes of accidents.

Black Spot Determination of Traffic Accident Locations and Its Spatial Association Characteristic Analysis Based on GIS

In general, the location of traffic accidents is described as an address with text, so they are difficult to display on the map. The paper discusses how to utilize the geocoding technology and VRS-GPS positioning technology to record the traffic accidents with Geo-spatial information. Based on the spatial relationship between traffic accidents and road network elements, two-way association relationship is defined by spatial relationship computation. Then the paper presents the method which takes the potential of reducing accidents as an index to extract the black spots. Finally, in the discussion, the association relationship between black spots and traffic attributes is used to analyze the factors that resulting in traffic accidents.

Sensitive Resource and Traffic Density Risk Analysis of Marine Spill Accidents Using Automated Identification System Big Data

This study developed a new methodology for analyzing the risk level of marine spill accidents from two perspectives,namely,marine traffic density and sensitive resources.Through a case study conducted in Busan,South Korea,detailed procedures of the methodology were proposed and its scalability was confirmed.To analyze the risk from a more detailed and microscopic viewpoint,vessel routes as hazard sources were delineated on the basis of automated identification system(AIS)big data.The outliers and errors of AIS big data were removed using the density-based spatial clustering of applications with noise algorithm,and a marine traffic density map was evaluated by combining all of the gridded routes.Vulnerability of marine environment was identified on the basis of the sensitive resource map constructed by the Korea Coast Guard in a similar manner to the National Oceanic and Atmospheric Administration environmental sensitivity index approach.In this study,aquaculture sites,water intake facilities of power plants,and beach/resort areas were selected as representative indicators for each category.The vulnerability values of neighboring cells decreased according to the Euclidean distance from the resource cells.Two resulting maps were aggregated to construct a final sensitive resource and traffic density(SRTD)risk analysis map of the Busan–Ulsan sea areas.We confirmed the effectiveness of SRTD risk analysis by comparing it with the actual marine spill accident records.Results show that all of the marine spill accidents in 2018 occurred within 2 km of high-risk cells(level 6 and above).Thus,if accident management and monitoring capabilities are concentrated on high-risk cells,which account for only 6.45%of the total study area,then it is expected that it will be possible to cope with most marine spill accidents effectively.

Analysis of Thorax Injuries in 112 Death Cases Caused by Traffic Accidents

Objective: To explore the characteristics and mechanisms of serious injuries of chest caused by road traffic accidents. Methods: Totally 112 autopsy cases with chest injuries in the urban of Jingzhou road traffic accidents were collected. Systematic review and analysis of the general information, postmortem examinations and assessments of chest injury had carried out from Feb. 2016 to Mar. 2018. Results: Average age of the victims was 52.2 years and the ratio of male to female deaths was 2.39:1. The proportion of motor-cyclists and pedestrians increased significantly. The overwhelming majority of accident vehicles were motorcycles and bicycles. Fractures of ribs and pulmonary contusion were the most common injuries. Craniocerebral and abdominal injuries were the most common associated injuries. Conclusion: Fractures of ribs and pulmonary contusion were the most common features of fatal road traffic injuries, often associated with vitreoretinal damage and serious multiple damages. These features reflect the characteristics of great violence in traffic accidents, which provides the evidence of identification of violent injuries.

Analysis of a Lightning Strike Accident of a Rural House and Defensive Measures

A lightning strike accident of a residential house in the rural areas of Neijiang is analyzed through on-site investigation,and the causes are discussed. Defensive measures of lightning disasters are proposed to provide reference for the prevention of lightning disasters in the construction of new countryside.

Cause Analysis of Wuhan Tianheng Building Pile Accident

The geological condition and the original structure feature and foundation design of Wuhan Tianheng building are described. The accident appearance of pile foundation in the construction execution of work is illustrated. The generating source of this pile foundation accident is analyzed in great details.

Acute group accident pattern analysis (accident of university student in dormitory at night)

Living in the dormitory is usually the requirement for university students who live far from the university. The medical disorder occurring at night among the university students is rarely reported. The acute problem due to accident is a topic of interest. Here, the authors summarize on pattern of accident at night of university students in a dormitory.

Study on coal mines accidents based on the grey relational analysis

The subject investigated the system of people-machine-environment in coal mines.The coal mines working process was researched and the theory of grey system was applied to analyze coal mines safety accidents and those relevant factors.This re- search reveals that this analysis method is easy and highly available and the result is of great credibility,which can not only provide theoretical supports to the quantitative study of coal mines safety accident,but offer basis for coal mines companies' safety management.

Traumatic Brain Injury and Cerebral Vascular Accident: Application of Rasch Analysis to Examine Differences in Disability and Outcome in Post-Hospital Rehabilitation

The purpose of this study was to demonstrate an application of Rasch analysis to identify differences in disability profiles resulting from traumatic brain injury (TBI) and cerebral vascular accident (CVA) and to examine outcome differences between the two groups following post-hospital residential rehabilitation. Participant data were collected from 32 facilities in 16 states. From 2990 neurologically impaired individuals with consecutive admissions from 2011 through 2017, 874 met inclusion criteria: TBI (n = 687) or CVA (n = 187), 18 years or older, minimum length of stay of one month, and maximum chronicity of 1 year. Participants were evaluated at admission and discharge on the Mayo Portland Adaptability Inventory-Version 4 (MPAI-4). Rasch analysis was performed to establish item reliability, construct validity and item difficulty. A Repeated Measures Multivariate Analysis of Covariance (RM MANCOVA) determined group differences and improvement from admission and discharge. Rasch Analysis demonstrated satisfactory construct validity and internal consistency (Person reliability > 0.90, Item reliability > 0.98 for admission and discharge MPAI-4s). Both groups showed significant improvement on the MPAI-4 (p 0.0005). The TBI group was more impaired on the adjustment scale at both admission and discharge (p 0.001). Rasch analysis identified two distinct impairment patterns. CVA participants exhibited deficits characteristic of focal impairment while the TBI group presented with deficits reflective of diffuse impairment. Rehabilitation was shown to be beneficial in reducing disability following neurologic injury in both groups. Importantly, Rasch Analysis accurately produced unique disability profiles that differentiated the treatment groups. This unique statistical technique offers a promising prescriptive hierarchical model for guiding neurological rehabilitation treatment.

Impact Analysis of the 2011 Fukushima Nuclear Power Plant Accidents by Running Spectrum Analysis on Newspaper

Huge amount of digital data of the Great East Japan Earthquake is provided by the highly-developed digital data technology. But the method and technique for analysis of these huge digital data are not developed sufficiently. This paper proposes a running spectrum technique for text data and analyzing changes of disaster phase during the disaster management cycle. Impact analysis of the nuclear power plant accidents have been performed by using Fukushima Minpo newspaper for its verification. The result shows the dynamic characteristics of the nuclear power plant accidents. As the time interval B becomes longer, the analysis data is used from wide range period along with the smoothing effect. When observing different time intervals B, fewer keywords have been ranked in the longer time intervals of B. The proposed technique is a powerful tool to effective and efficient disaster response and management. analyze effectively the huge amount of digital data for the

Spatial Analysis of Traffic Accidents in the City of Medina Using GIS

The general objective of this research is to determine how to use the spatial analysis of traffic accidents in Medina Menorah City through geographic information systems. This research aimed to identify, locate and define the sites where traffic accidents are concentrated and determine the need to apply specific safety standards to reduce accidents and identify their causes thereof. This current research applied the analytical descriptive approach for its relevance with this specific research. This research collected traffic accidents data from the Ministry of the Interior, Department of General Traffic. That data captured the hotspots accidents in Medina Menorah City. Some of the most important results of the study are as follows: many roads were selected as High Accident Location HAL, such as Central Ring Roads, King Faisal bin Abdul-Aziz Road, Prince Abdul Majid bin Abdul-Aziz Road, and King Abdulla bin Abdel-Aziz Road. The high-speed roads are heavily linked to the massive increase of traffic accident rates, and the increase in the street section length led to the soaring number of total accidents. The study recommended performing more studies and different highway safety studies to identify and locate accident patterns on road networks. Due to the fact that the accidents concentration is intensely focused on Medina City center and Prophet’s Mosque, it is a must to increase the number of public transportations to and from Prophet’s Mosque, particularly during the Hajj period, because of the fact that the visitors of Prophet’s Mosque is on the increase during the said period. This study can be applied in other cities because knowing the locations of traffic crash hotspots can provide us with valuable insights into the causes of accidents and this knowledge helps decision-makers to better assess the risk associated with accidents.

A Comparative Analysis of English and Chinese News on MH370 Accident from the Appraisal Perspective

Appraisal Theory is a further development of interpersonal function in systemic functional linguistics. Based on the subsystem-attitude system in Appraisal Theory, an attempt is made to conduct a comparative analysis of attitudinal resources in English and Chinese news on MH370 accident. Meanwhile, certain attitudes or stances conveyed by the authors of these news will be revealed through some typical examples. Both quantitative and qualitative methods are adopted in the present study to make a statistical and interpretive analysis of the collected materials. It is found that both English and Chinese news contain many attitudinal resources. There are similarities and differences concerning the distribution of attitudinal resources between English and Chinese news. The findings suggest that though news is expected to be objective and factual, it may imply the authors＇ subjective attitudes to some extent. So readers should get hang of the different opinions and stances hidden behind different news reporting so as to improve abilities to appreciate and differentiate different news.

Effective Measure for Accident Prevention Onboard Sea Vessels—Improvements on 4M4E Analysis

The 4M4E analysis is a type of root-cause analysis that can multilaterally pinpoint the trigger factors of an accident or disaster using its analytic capabilities and can clarify various countermeasures against each trigger factor.This study aims to reduce the number of vessel accidents and disasters involving seafarers by improving the practical use of 4M4E analysis.Vessel accidents or disasters involving seafarers,related to a mooring line,sometimes result in a fatality;therefore,this research area has attracted international attention.In consideration of this,we devised an analysis method for accidents involving a mooring line by adding prediction to the 4Ms of 4M4E,having first extracted the potential causes of an accident through brainstorming.The 4M4E+P analysis could obtain additional trigger factors that were not revealed in the 4M4E analysis.Thus,a measure of adopting these newly acquired trigger factors was evaluated.In addition,it is thought that 4M4E+P analysis can reduce the risk of vessel accidents and disasters involving seafarers.

Effect analysis of the intentional depressurization on fission product behavior during TMLB' severe accident

It has been found that the pressure in the reactor coolant system (RCS) remains high in some severe accident sequences at the time of reactor vessel failure, with the risk of causing direct containment heating (DCH). Intentional depressurization is an effective accident management strategy to prevent DCH or to mitigate its consequences. Fission product behavior is affected by intentional depressurization, especially for inert gas and volatile fission product. Because the pressurizer power-operated relief valves (PORVs) are latched open, fission product will transport into the containment directly. This may cause larger radiological consequences in containment before reactor vessel failure. Four cases are selected, including the TMLB' base case and the opening one, two and three pressurizer PORVs. The results show that inert gas transports into containment more quickly when opening one and two PORVs, but more slowly when opening three PORVs; more volatile fission product deposit in containment and less in reactor coolant system (RCS) for intentional depressurization cases. When opening one PORV, the phenomenon of revaporization is strong in the RCS.