Accidents electrical failure

Electrical Failures and Computer Failures Nuclear Accidents Natural Disasters... 

An arrhythmia can be broadly defined as any significant deviation from normal cardiac rhythm.6 Various problems in the origination and conduction of electrical activity in the heart can lead to distinct types of arrhythmias. If untreated, disturbances in normal cardiac rhythm result in impaired cardiac pumping ability, and certain arrhythmias are associated with cerebrovascular accidents, cardiac failure, and other sequelae that can be fatal.1,2 16 Fortunately, a variety of drugs are available to help establish and maintain normal cardiac rhythm. 

The accident at TMI-2 was initiated at 4 am by a minor malfunction, or transient, in the non-nuclear part of the reactor. The main feed-water pumps stopped running, caused by either a mechanical or electrical failure, which prevented the steam generators from removing heat. This minor event would... 

Over the years, risk and vulnerability analysis (RVA) has been appUed and adapted for various infrastructures. However, these analyses often do not evaluate the effects of undesired events across sectors. The need for a unified approach to such analyses is addressed in the research project DECRIS (Risk and Decision Systems for Critical Infiastructures). The main objective of DECRIS is to develop an all-hazard generic RVA suitable for a cross-sector infrastmcture analysis. Both safety (accidents, technological failures etc.) and security (dehberate actions) aspects are included. A general case study of the city of Oslo, Norway, focusing on imdesired events in the infrastructures electric supply, water supply, transportation, and ICT, has been carried out (Utne et al. 2008). 

A partial loss of coolant flow accident can result from a mechanical or an electrical failure of a reactor coolant pump or from a fault in the power supply to the pump or pumps. If the reactor is at power at the time of the event, the immediate effect of the loss of coolant flow is a rapid increase in the coolant temperature. A complete loss of flow accident may result from a simultaneous loss of electrical suppHes to the reactor coolant pumps. If the reactor is at power at the time of the accident, the immediate effect of a loss of coolant flow is a rapid increase in the coolant temperature. 

External events are accident initiators that do not fit well into the central PSA structure used for "internal events." Some "external events" such as fire due to ignition of electrical wires, or flood from a ruptured service water pipe occur inside the plant. Others, such as earthquakes and tornados, occur outside of the plant. Either may cause failures in a plant like internal events. External initiators may cause multiple failures of independent equipment thereby preventing action of presumably redundant protection systems. For example, severe offsite flooding may fli 1 the pump room and disable cooling systems. An earthquake may impede evacuation of the nearby populace. These multiple effects must be considered in the analysis of the effects of external events. 

Accident progression scenarios are developed and modeled as event trees for each of these accident classes. System fault trees are developed to the component level for each branch point, and the plant response to the failure is identified. Generic subtrees are linked to the system fault trees. An example is "loss of clcciric power" which is analyzed in a Markov model that considers the frequencies of lo,sing normal power, the probabilities of failure of emergency power, and the mean times to repair parts of the electric power supply. 

Before entry is allowed into a vessel or other confined space, the vessel should be isolated from sources of hazardous material by slip-plating or physically disconnecting all pipelines and by isolating all supplies of electricity, preferably by disconnecting the cables. On the whole, these precautions seem to be followed. Accidents as the result of a failure to isolate are less common than those resulting from a failure to remove hazardous materials or from their deliberate reintroduction as described in Sections 11.1 and 11.2. However, the following are typical of the accidents that have occurred. 

Electrical isolation Heat radiation Cooling coils Recent incidents Vacuum relief valves Accidents at sea Fires Problem sources Emulsion breaking Chimney effects Interlock failure Choosing materials. 

On July 24,1994, an explosion followed by a number of fires occurred at 13 23 at the Texaco refinery in Milford Haven, Wales, England. Prior to this explosion, around 9 a.m., a severe coastal electrical storm caused plant disturbances that affected the vacuum distillation, alkylation, butamer, and FCC units. The explosion occurred due to a combination of failures in management, equipment, and control systems. Given its calculated TNT equivalent of at least 4 tons, significant portions of the refinery were damaged. That no fatalities occurred is attributed partially to the accident occurring on a Sunday, as well as the fortuitous location of those who were near the explosion. 

Sometimes two other incidents are attributed to LNG The first one - a construction accident on Staten Island in 1973 - was cited as a LNG accident because work was carried out inside an empty LNG tank. The second - an electrical seal failure on a LNG pump that failed in 1979 - caused an explosion because gas (not LNG) entered an enclosed building. This event gave rise to a thorough revision of the code for electrical seals used with all flammable fluids underpressure [10],... 

Fusion power generators are inherently safe. The magnetic confinement of the plasma must be carefully controlled and balanced to sustain the nuclear reaction. Any disturbance of the operating conditions will result in termination of the reaction. No combination of system failure, operator error, natural disaster or sabotage can cause the fusion reaction to run away. A nuclear explosion, melt down or similar catastrophic accident is not possible. A violent event, one of sufficient magnitude to disrupt the total reactor, could cause a chemical or electrical fire similar to any industrial fire. 

Protection against component failure accidents is well understood in engineering. Principles for safe design of common hardware systems (including sensors and actuators) with standard safety constraints are often systematized and encoded in checklists for an industry, such as mechanical design or electrical design. In addition. 

In nuclear installations the so-called design basis accidents are used for this purpose [19]. For example, the complete failure of the main coolant pipe of a reactor ( 2-F — rupture because the entire cross section is open on both sides) or the failure of the electric supply [19]. The design basis accidents serve to determine the type and dimensions (e.g. capacity, temperatures, cooling power...) of the corresponding safety systems, for example the emergency cooling system for counteracting the breach of the main coolant pipe. 

The tissue damage is very dependent on exposure time cells can tolerate long time exposure of 43 °C. Above about 45 °C, the time duration becomes more and more critical. In high-voltage accidents, the heat effect may be very important, and patients are treated as thermal burn patients. In particular, special attention is paid to the fluid balance, because electrical bum patients tend to go into renal failure more readily than thermal bums of equal severity. As electric current disposes thermal energy directly into the tissue, the electric bum is often deeper than a thermal bum caused by thermal energy penetrating... 

Fire (radiological and toxic material) Forklift fire incident causes transfer cask breach with possible target exposure and airborne release Failure of electrical equipment or system in SCBs, SGB, ventilation hood, Zone 2 or Zone 2A canyon Lightning strike External fire (vehicle accident, aircraft crash, other building fire) irradiated isotope production target, up to 20,000 curies. Volatiles in process cold traps, up to 70,000 curies. Same material as toxic spill. Residual radiological contamination. 

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