System Redundancy

Redundancy of slurry delivery systems or system components is an emotional and user-specific decision. While all manufacturers strive to make dispense systems and all peripherals as reliable as possible, compromises must be made for cost, space, slurry lifetime, and manufacturing philosophy. In the end, it usually comes down to how much one is willing to pay for 99.99% uptime versus 99% uptime. Some of the common strategies employed include 

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There is no standard or specification within the industry which specifies the dual redundancy for PLCs used for process control functions. The requirement for control system redundancy is primarily a function of the desired availability or demand of the process control system. Most control sytem availability percentages are in the range of 99 to 99.9%. Depending on the type of PLC system configuration defined, availability generally improves in relation to the amount of redundancy added to the various system components, but does not necessarily improve system reliability. 

Facilities may also want to consider security improvements. Security and general infrastructure may provide significant multiple benefits. For example, improved treatment processes or system redundancies can both reduce vulnerabilities and enhance day-to-day operation. 

Redundant piping system. Redundant piping systems can be installed, especially in conjunction with dual daytanks, to enable a complete cleanout of the delivery system between slurry batches. When this degree of redundancy is chosen, a totally separate slurry dispense machine is included to permit a backup for all major components. 

Mantovani, A. (1999). The chemokine system Redundancy for robust outputs. Immunol. Today 20, 254-257. 

OQ should include backup and recovery, data archive and retrieval, security, system administration procedure verification, startup and shutdown, UPS continuity, communications loss and recovery, and systems redundancy challenges such as mirrored drives, secondary systems, and failsafe systems. 

The SurePower system uses four phosphoric acid fuel cells made by UTC Fuel Cells which provide 320-kW for critical power needs. The fuel cells are combined with flywheels and advanced electronics to minimize the affects of disruptions. Each of the four fuel cells provides 200-kW, so the system redundancy achieves the high availability. 

Tt is a complex and tedious task to understand completely the behavior and interaction of biological systems. Redundancies, interactions, and complexities are well beyond what might be imagined necessary for a physical or engineering system. Regardless of this, ideas are formed on the interaction of components, and theories are advanced to explain the behavior of biological systems. These ideas and theories constitute conceptual models which are evaluated and tested in experiments designed for that purpose. 

Data to be transferred from existing systems are reviewed prior to transfer to the new system. Redundant data are removed from the transfer list, and a data upload mechanism is identified. Data upload is carried out, either manually or automatically, and a readiness review is conducted to check all items are in place before the big day and "go live" (see Figure 8.2). 

Equipment arrangement involves the concepts of series and parallel systems as well as standby systems. Redundancy can just be duplication of the procedure, but it also can be having some information confirm the remainder—an error-checking code. For example, giving a meeting date as Thursday, February 25, lets the Thursday confirm the 25. A ZIP code confirms the names of city and state on a postal address. 

Multiple paddles and rows provide substantial system redundancy. 

Mantovani A. The chemokine system redundancy for robust outputs. Immunol Today 1999 20 254-257. 

Some of the more common engineering controls are fire alarms and detection systems, toxic gas alarms and detection systems, redundant alarms and shutdown devices, automatic shutdown devices, and process containment systems. 

Reactor faults can act rapidly, allowing no time for operator action should the protection fail. In these circumstances it is vital to have a number of lines of identically protecting systems (redundancy) to maintain safety. Defence in depth is provided. For example, containment of fission products is ensured by a combination of fuel integrity, cladding, pressure vessel integrity and containment structures. 

The objective of the CMA is to identify aU possible common mode failures which have the potential to fail, or degrade, system redundancy or to cause another initiating event leading to system failure. 

The fault tree analysis describes a hazardous top event and the basic event which maybe leads to such a top event in a top-down method. The methods are dev-ided in static fault tree analysis and dynamic fault tree analysis. The static fault tree analysis describes the system top event in static way. In further steps it is not possible to describe functional system redundancy with this static Fault Tree Analysis (FTA). Especially if cold and hot spares are integrated or if triggers are used, the static fault tree analysis is unsatisfying these requirements. Therefore it is more suitable to use the extended Dynamic Fault Tree Analysis. The DIFTree (Dynamic Innovative Fault Tree) software package could be a helpful tool for the system development... 

Apphcation of both principles allowed to use as much as possible standard components (diversity) and enhance reliability of the sensor system (redundancy). 

Redundancy Redundancy can reduce the probability of error or failure in an operation or system. Redundancy means providing more than one means to accomplish something, where each means is independent of the other. 

The Freeport McMoran and Spool systems have redundancy at the main contact end whereas the Outotec system redundancy is provided on the equalizer bar. This equalizer bar contact will have low contact resistance since it carries full electrode weight but there will be an additional contact resistance and equalizer bar resistance needed to carry the current to that contact. 

Total Lo s of the Cold Source (water) Separate cooling water stem mMfnial and safety systems, redundancy... 

This study assessed the consequences of both internal and external initiators. The study found that DHR-related core damage risk is in a range between 7 x E-5 and 4 x E-4 per reactor year with an average value of 2 x E-4. This, along with other results (i.e. lack of system redundancies, lack of separation, general system arrangement, human errors, etc.), suggested that the resolution of this issue would need to be plant specific. 

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