Showing papers on "System safety published in 1988"

Reliability engineering & system safety

Abstract: Reliability Engineering and System Safety is an international journal devoted to the development and application of methods for the enhancement of the safety and reliability of complex technological systems, like nuclear power plants, chemical plants, hazardous waste facilities, space systems, offshore and maritime systems, transportation systems, constructed infrastructure and manufacturing plants. The journal normally publishes only articles that involve the analysis of substantive problems related to the reliability of complex systems or present techniques and/or theoretical results that have a discernable relationship to the solution of such problems. An important aim is to achieve a balance between academic material and practical applications.

Modern accident investigation and analysis

Abstract: The Need for Investigation. Preparing for Mishaps. Getting Underway with the Investigation. Human Aspects. The Environment. Materials. Systems Investigation. Basic Analytical Technique. System Safety/Faulty Tree. Change Analysis. Multilinear Events Sequencing. Management Oversight and Risk Tree (MORT). S-T-E-P Accident Investigation. Technique of Operations Review. Where Did Management Fail? Fire Investigation. The Mishap Report. 12 Steps to Mishap Investigation. A Generic Approach to Mishap Investigation. Legal Aspects of Investigation. What is Ahead for Investigation? Appendices.

Occupational Safety and Accident Prevention: Behavioral Strategies and Methods

Abstract: Introduction. Accident Statistics and Analytical Frameworks. Hazard and Safety Analysis. Hazard Cognition and Risk-Taking Behavior. Human Reliability. Safety Studies with Special Emphasis on High Risk Technologies. Improving Safety and Personal Reliability.

How to improve the effectiveness of hazard and operability analysis

Abstract: The key elements that make the hazards and operability (HAZOP) technique effective for identifying chemical process hazards are outlined. Six categories of problems that can sometimes reduce the effectiveness of HAZOP and even prevent it from discovering some major hazards are explained. Several examples are included to show how lack of experience, failure to communicate, management shortcomings, complacency and poor loss-prevention practices, a shortage of technical information, and other limitations, each contribute to the problem. Practical solutions are recommended for countering the difficulties and for making the HAZOP a more effective risk-management tool. >

Triggering device for a safety system

Abstract: The invention relates to a triggering device for safety systems in motor vehicles which is equipped with a trigger sensor for activating these safety systems, an electronic sensor system for detecting the buckling speed being assigned to this trigger sensor. An exemplary embodiment is described and outlined in figures of the drawing.

A mathematical analysis of human-machine interface configurations for a safety monitoring system

Abstract: Two human-machine interface configurations for safety monitoring systems are discussed: (1) A conventional fault-warning configuration, which gives an alarm message on detecting plant failure and (2) a safety-presentation configuration introduced here, which can give a safety message as well as an alarm message. It is proved mathematically that the safety-presentation configuration is superior to the fault-warning configuration in the well-defined sense of avoiding catastrophic accidents. >

Human factors and decision making : their influence on safety and reliability

Abstract: Human Factors in Safety.- Human Factors in the Process Industries.- Human Factors Considerations in the Safety Case for the Channel Tunnel Project.- Safety and Human Factors in Manned Space Flight Systems.- The Role of Technical Documentation for Maintenance Staff in the Safe Operation and Maintenance of Machine and Processes.- Allocation of Function Between Man and Programmable Electronic Systems in Safety-Related Applications.- Human Reliability Assessment.- Human Reliability Assessors Guide: An Overview.- A Comparative Evaluation of Five Human Reliability Assessment Techniques.- Human Factors Reliability Benchmark Exercise, Report of the SRD Participation.- The Application of the Combined THERP/HCR Model in Human Reliability Assessment.- A Practical Application of Quantified Risk Analysis.- PROF a Computer Code for Prediction of Operator Failure Rate.- New Directions in Qualitative Modelling.- Human Factors in Management and Design.- Management Factors and System Safety.- Addressing Human Factors Issues in the Safe Design and Operation of Computer Controlled Process Systems.- Management in High Risk Industries.- Processor-Based Displays: The Flexible Control Panel.- A Human Factors Data-Base to Influence Safety and Reliability.- Decision Support Systems.- Modelling the Evacuation of the Public in the Event of Toxic Releases: A Decision Support Tool and Aid for Emergency Planning.- Designing Decision Support Systems for Human Error Reduction: The Need to Address Information Distortion.- Supporting Expert Judgement of Human Performance and Reliability.

The role of hazard and operability study in risk analysis of major hazard plant

Abstract: Under the CIMAH Regulations and the Seveso Directive the operators of major hazard plant and storage are required to prepare a safety case. The essential elements of a safety case are: the safety policy, description of hazards arising from the activity, account of controls to minimize the effects of these hazards, consequences should these controls fail, on/off site emergency plans etc. The proven method of hazard identification, called the Hazard and Operability Study, is used extensively to enhance the safety of plant during design and for existing plant. The study gives a better value for money in the art of hazard identification than the checklist approach and may be used for (a) future modifications; and (b) as a support document for ‘Safety Case’ preparation for identification of top events and for constructing fault/event trees for further frequency analysis. This paper highlights how the technique has been used in Snamprogetti Ltd at the design and operational stages of the plant.

A production system for intelligent monitoring systems

Abstract: Conventional monitoring systems use data-collection techniques to obtain sensor data about various aspects of hazardous workplaces such as coal mines and provide warnings. However, they are ill-equipped for making complex decisions involving large amounts of interrelated data. Laser/RPS, a C language-based object-oriented production system, is presented, and those programming system features that can be used to develop intelligent monitoring systems are described. Potential applications of this system to underground coal mine monitoring systems are discussed. >

Evaluation of the Quality of Safety and Risk Analysis in the Chemical Industry

Abstract: Safety and risk analyses have often been criticized as incomplete and inaccurate. This criticism, however, lacks a sound basis, since there has been little scientific evaluation of the methods developed for safety and risk analysis. The aim of this paper is to present a proposal for establishing measures—reliability, validity, and coverage—to be used in the evaluation of the scientific quality of the hazard identification and accident modeling phases in safety and risk analysis. The paper also presents four main principles for the evaluation of the scientific quality, and a theoretical framework to be used in evaluation. The framework is illustrated with practical examples taken from the chemical industry.

The integration of a formal safety analysis into the future software engineering process: An example from the pacemaker industry

Abstract: An example from the cardiac pacemaker industry of safety-orientated software-design methodology is provided. Safety consideration begins upon product description with a hazard analysis whereby potential hazards are classified according to their criticality and rough probability of occurrence. The completed hazard analysis determines the software safety requirements which specify what the system will not do. A system-hazard cross-check matrix is defined that serves to direct the design team to those areas requiring more scrutiny. Traceability matrices provide a verifiable link from safety requirements design to the actual code. This methodology should serve to minimize hazards in the final software product. >

Reasoning and Representation in RiTSE

Abstract: RiTSE, the Reactor Trip Simulation Environment, is a frame and rule-base artificial intelligence (AI) application which aids nuclear power plant operators in determining if a proposed change in a state of a component or process will cause safety systems to automatically shut the plant down. This paper stresses the software techniques used to implement the system.

Express: An Expert System to Perform System Safety Studies

Abstract: This paper presents EXPRESS, an expert system developed for the automation of reliability studies. The first part consists in the description of the method for static thermohydraulic systems. In this step, we define the knowledge representation based on the two inference engines -ALOUETTE and LRC developed by EDF. We explain all the process to construct a fault tree from a topological and functional description of the system. Numerous examples are exhibited in illustration of the method. This is followed by the lessons derived from the studies performed on some safety systems of the PALUEL nuclear power plant. The development of the same approach for electric power systems is described, insisting on the difference resulting from the sequential nature of these systems. Finally we show the main advantages identified during the studies.

Seismic Design and Construction of Complex Civil Engineering Systems

Abstract: This publication presents information about practices for planning, designing, and constructing civil engineering systems for mitigating earthquake effects. Concepts dealing with defining seismic hazards that have the potential to impact these systems are discussed. Design topics include procedures for evaluating damage mechanisms for systems, factors relating to optimal order for post-earthquake repairs, earthquake effects on structural components, and assessment of damage potential. Soil stability and the potential of liquefaction and landslide are also discussed. Other topics include seismological characteristics of the fault at New Madrid, modeling failure criteria and computing expected loss, and system safety considerations relating to the design of the Sylmar electric power converter station.

Failsafe design of closed loop systems

Abstract: A general approach for designing closed-loop systems that will be safe in the presence of hardware failures in medical instruments is presented. Specific recommendations to attain a fail-safe system are made (i.e. hardware and software features). Special attention is paid to checking the read-only and random-access memories. >

Expert systems for the analysis of transients on nuclear reactors: SEXTANT, a general-purpose physical analyzer

Abstract: Two expert systems for on-line analysis of nuclear reactor transients are reported. During a hypothetical crisis in a nuclear facility, a team of the Institute for Protection and Nuclear Safety must assess the risk to the local population. Expert systems are intended to assist in this analysis. The first deals with the availability of the safety systems of the plant (e.g., emergency core cooling system), depending on the functional state of the support systems. A second expert system will be built to study the physical transient of the reactor (mass and energy balance, pressure, flows). To do this, as in the development of the other expert systems, a physical analyzer is required. This is the aim of SEXTANT, which combines several knowledge bases concerning measurements, models, and qualitative behavior of the plant with a conjecture-refutation mechanism and a set of simplified models of the current physical state. A prototype is being assessed with integral test facility transients.

Process safety management: A U.K. approach

Abstract: Process safety in the UK is discussed from both the legal and management standpoints. General safety legislation requires a formal statement of company policy and arrangements for managing safety, but allows freedom for an organization to decide what those arrangements should be. The basis of a company-wide approach to process safety management that meets legal requirements is outlined. Some of the main points requiring attention for effective process hazard recognition, assessment and control on a continuing basis are discussed.

Self-checking safety interlock system

Abstract: A more reliable electrical self-checking interlock system is discussed that meets the desired goals of safety shutdown systems. The design, operating principles, and performance characteristics of the microprocessor-based, self-checking, safety interlock system are described. The system was designed and implemented in a large plant. The system has substantially improved safety and environmental control of the processes, in addition to its inherent advantages of process analysis and optimization over conventional systems. With some modification the system can be programmed to verify functionality of the final interlock elements for additional safety improvement. >

Gas turbine safety improvement through risk analysis

Abstract: This paper is intended to provide the engineer with the information necessary to understand certain statistical methods that are used to improve system safety. It will provide an understanding of Weibull analysis, in that it describes when the Weibull distribution is appropriate, how to construct a Weibull plot, and how to use the parameters of the Weibull distribution to calculate risk. The paper will also provide the engineer with a comprehension of Monte Carlo simulation as it relates to quantifying safety risk. The basic components of Monte Carlo simulation are discussed as well as the formulation of a system model and its application in the gas turbine industry.

A method for identification of human originated test and maintenance failures

Abstract: In order to improve the coverage of PRAs (probabilistic risk assessments) and the maintenance planning at nuclear power plants, the Technical Research Centre of Finland has developed a method for identification of possible test-and-maintenance-caused common-cause failures. The method has been tested in analyses of safety-related systems at a nuclear power plant in Olkiluoto, which consists of two 660 MW BWR (boiling water reactor) units. The method is praxis-oriented and provides a simple way to cluster operating and maintenance experience to improve safety. The starting point of the method is to go through a process systematically in group sessions and by using a special form. Identified possible common-cause failures are classified into three categories with respect to the risk they are considered to cause to the installation. >

A condition monitoring system for high pressure natural gas transmission plant

Abstract: The delivery of natural gas through the National Transmission System into the twelve regional systems and ultimately on to the consumer, requires a number of control functions to be performed. The major objectives when performing these functions can be broadly summarised as follows. System safety, integrity and security of supply. Minimisation of operating costs. Optimization of flow capacity and storage utilisation. Modern control technology coupled with the major advances in electronic microprocessor technology provided the basis for the development of schemes to overcome the current operational problems and thereby greatly improve the efficiency of control. The author briefly describes a microprocessor based control strategy which has been successfully implemented to overcome many of the operational problems and goes on to illustrate a strategy which provides a reliable condition monitoring system applicable to NTS offtakes. The ultimate condition monitoring system is embedded within the existing microprocessor based control structure in an attempt to avoid any possible degradation in terms of overall system reliability, which is always a major consideration in such applications. >

A matrix safety frame approach to robot safety for space applications

Abstract: The planned use of autonomous robots in space applications has generated many new safety problems. This thesis assesses safety of autonomous robot systems through the structure of a proposed three-dimensional matrix safety frame. By identifying the common points of accidents and fatalities involving terrestrial robots, reviewing terrestrial robot safety standards, and modifying and extending these results to space applications, hazards are identified and their associated risks assessed. Three components of the safeguarding dimension of the matrix safety frame, safeguarding through design and operation for intrinsic safety, and incorporation of add-on safety systems are explained through examples for both terrestrial and space robots. A space robot hazard identification checklist, a qualitative tool for robot systems designers, is developed using the structure imparted by the matrix safety frame. The development of an expert system from the contents of the checklist is discussed.