Safety vulnerability

The following four steps can help you reduce the safety vulnerability of remote workers. These tips apply to all employees, and their management, who must work alone or with others in remote locations where normal means of communication are unreliable or nonexistent. 

Neither choice would present incremental nuclear safety vulnerability - because the reactor is designed to passively accommodate a loss of heat sink accident and, therefore, a flibe pipe break or freeze-up is expected to present no hazard to the reactor. A decision is yet to be made between the two approaches. 

Step 1 Identify key safety issues of concern— This can be done through different types of safety analyses. Chapters 5 through 9 discuss different safety analysis techniques that can identify where safety vulnerabilities currently exist and where you may have future problems if hazards aren t better controlled. 

To allow a wide range of existing assessment techniques to be used, new techniques to be developed, and yet still retain a cohesive assessment methodology. This allows the type of assessment to Include personnel safety, vulnerability of equipment to hazards and the assessment of PES reliability and availability. 

Systems seem to have both a bright side and a dark side. The bright side is when the system works as intended and performs its intended function without a glitch. The dark side is when the system encounters hardware failures, software errors, human errors, and/or sneak circuit paths that lead to anything from a minor incident to a major mishap event. The following are some examples of the dark side of a system, which demonstrate different types and levels of safety vulnerability ... 

Since a function performs a desired task, the erroneous performance of a function, or the failure to perform a function when needed, may result in serious safety consequences. Erroneous function and failure to function can result from many different or combined causal factors, such as hardware failures, hardware tolerance errors, system timing errors, software errors, human errors, sneak circuits, and environmental factors. The criticality of the function typically determines the safety vulnerability involved. Functions can be real or abstract entities in a system, and they should be recognized in an overall system functional hierarchy. 

Safety vulnerability is the susceptibility of a system to hazards and mishap risk. Safety vulnerability is not equal among systems some systems have more vulnerability than others. Safety vulnerability results from many different driving factors, such as hazardous system components, system size, system complexity, and system application. 

Understanding the safety vulnerabilities within a system is important because it drives the SSP tasks and cost. It also delineates the relative system risk and criticality that can be expected from the system. A system s safety vulnerability is determined through HA and risk assessment. 

The confluence of sharply rising Operations and Maintenance (O M) costs. NRC requested Individual Plant Examinations (IPEs) and increased personal computer capabilities gave rise to the R R Workstation. Its uses and maintains-current PSA models and databases for individual plants to perform O M planning and scheduling, and uses the PSA in IPE models to identify plant design, procedure and operational vulnerabilities. The Risk and Reliability Workstation Alliance was organized by EPRI to support the R R Workshop in order to achieve O M cost reduction, plant productivity and safety enhancement through risk-based, user-friendly, windowed software louls (Table 3.6 8). The Alliance, initiated in 1992, includes 25 U.S. utilities and four international partners from Spain, France, Korea, and Mexico. SAIC is the prime contractor for the R R Workstation, with participation of five other PSA vendors. 

The Severe Accident Policy Statement formulates systematic safety examinations for detection of accident vulnerabilities and implementation of cost-effective changes. The NRC issued Generic Letter 88-20 to implement this plan through IPEs. While the primary goal was the identification of plant vulnerabilities, no definition of vulnerability was provided. Only 4 operators of BWRs identified vulnerabilities and only 16 operators of PWRs did so. Over 500 plant improvements were identified, but few vulnerabilities were. 

The IPE Program, while identifying few plant-specific severe accident vulnerabilities suseeptible to low-cost fixes, served as a catalyst for improving the overall safety of nuclear pow. e.r plants, Furthermore, improvements at one plant may be applicable to another plant,... 

The first step in minimizing accidents in a chemical phuit is to evaluate the facility for potential fires, explosions, and vulnerability to other liazards, particularly those of a chemical miture. This calls for a detailed study of plant site and layout, materials, processes, operations, equipment, and training, plus an effective loss prevention program. The technical nature of industry requires detailed data and a broad range of experience. Tliis complex task, today becoming the most important in plant design, is facilitated by the safety codes, standiu ds, and practice information available. The technical approach to evaluating die consequences of hazards is discussed later in tliis cliapter and in Part V (Chapters 20 and 21). 

Biodiesel does not present any special safety concerns. Pure biodiesel or biodiesel and petroleum diesel blends have a higher flash point than conventional diesel, making them safer to store and handle. Problems can occur with biodiesels in cold weather due to their high viscosity. Biodiesel has a higher degree of unsaturation in the fuel, which can make it vulnerable to oxidation during storage. 

The sociopolitical consequences of increased commitment to nuclear technologies which represent only 5 percent of world energy, raises questions of democratic decision-making to safeguard the environment and health and safety of the general public (Holdren, 1976). Some ask if it is worth the price. Research on the social and political implications identifies the crucial contrast between vulnerable and nonvulnerable technologies, and between technological waste and social waste. 

The design requirements for intrinsically safe would seem to be demanding, and a review of NFPA 493 enforces this fact. Today s industrial environment imposes additional requirements not only on the use of intrinsically safe electrical circuits, but other hazardous electrical techniques as well. These requirements are due to the Occupational Safety and Health Act and the employer s increasing vulnerability for liability. 

The way of using the index is flexible. Comparisons can be made at the level of process, subprocess, subsystem, or considering only part of the factors (e.g. only process oriented factors). Different process alternatives can be compared with each other on the basis of the ISI. Also the designs of process sections can be compared in terms of their indices in order to find the most vulnerable point in the design. Sometimes a comparison based on only one or two criteria is interesting. E.g. a toxicity hazard study can be done by considering only the toxic exposure subindex. Because its flexibility the total inherent safety index is quite easily integrated to simulation and optimization tools. 

A chemical engineer may have a choice of inherent safety variables, such as quantity stored or process temperatures and pressures, or process safety measures such as emergency isolation valves or containment systems, all of which may greatly reduce the vulnerabilities or the consequences of intentional loss. These are in addition to traditional security measures, which may include physical security, background checks, administrative controls, access controls, or other protective measures. For a more complete discussion of the options, refer to the AIChE Center for Chemical Process Safety Guidelines for Analyzing and Managing the Security Vulnerabilities of Fixed Chemical Sites and other references.f... 

American Institute of Chemical Engineers Center for Chemical Process Safety Guidelines for Analyzing and Managing the Security Vulnerabilities of Fixed Chemical Sites, 2002. 

Kennedy R., Kirwan B., 1998. Development of a Hazard and Operability-based method for identifying safety management vulnerabilities in high risk systems, Safety Science 30, pp. 249-274. 

As can be seen, the real cause of most accidents is what might be classified as human errors. Most people have good intentions to perform a function properly, but where shortcuts, easier methods or considerable economic gain opportunities appear or present themselves, human vulnerability usually succumbs to the temptation. Therefore it is prudent in any organization, especially where high risk facilities are operated, to have a system in place to conduct considerable independent checks, inspections, and safety audits of the design and construction of the installation. 

Both qualitative and quantitative evaluation techniques may be used to consider the risk associated with a facility. The level and magnitude of these reviews should be commensurate with the risk that the facility represents. High value, critical facilities or employee vulnerability may warrant high review levels. While unmanned "off-the-shelf, low hazard facilities may suffice with only a checklist review. Specialized studies are performed when in-depth analysis is needed to determine the cost benefit of a safety feature or to fully demonstrate the intended safety feature has the capability to fully meet prescribed safety requirements. 

A high pressure process or storage vessel should never be "pointed" at manned or critical facilities or other high inventory systems for concerns of a BLEVE of the container with the ends of the vessel rocketing towards the vulnerable location. As a further inherent safety enhancement, spheroid separation vessels may be used in some instances instead of horizontal pressure vessels (bullets). This reduces the possibility of a BLEVE incident directed towards other exposures. 

Normally where it is necessary, fireproofing is preferred over water spray for several reasons. The fireproofing is a passive inherent safety feature, while the water spray is a vulnerable active system that requires auxiliary control to be activated. Additionally the water spray relies on supplemental support systems that may be vulnerable to failures, i.e., pumps, distribution network, etc. The integrity of fireproofing systems is generally considered superior to explosion incidents compared to water spray piping systems. The typical application of water sprays in place of fireproofing is for vessel protection. 

Some points to consider related to the six basic elements listed above are included in table 5.1. The manner in which the vulnerability assessment is performed is determined by each individual water/wastewater utility. Throughout the assessment process it is important to remember that the ultimate goal is twofold to safeguard public health and safety and to reduce the potential for disruption of a reliable supply of chemicals. 

A study included a survey that found that many water utilities were doing little to secure their SCADA network vulnerabilities (Ezell 1998). For example, many respondents reported that they had remote access, which can allow an unauthorized person to access the system without being physically present. More than 60 percent of the respondents believed that their systems were not safe from unauthorized access and use. Twenty percent of the respondents even reported known attempts, successful unauthorized access, or use of their system. Yet twenty-two of forty-three respondents reported that they do not spend any time ensuring their network is safe, and eighteen of the forty-three respondents reported that they spend less than 10 percent ensuring network safety. 

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