Plants protection systems

Fire extinguishing systems can include foam, carbon dioxide and dry chemical. Wetting agents and high e.xpansion foam have been used in some plant protection systems. All fire extinguishing systems should be evaluated for the potential health risks as well as overall effectiveness before incorporation into a plant. 

To understand the principles and rules of organic plant protection and the differences between the various plant protection systems it is first necessary to look at some principles of general ecology. 

The physical separation of redundant sections of plant protection systems is usually one of the fundamental defences against the consequences of these events. 

Anticipated operational occurrences are off-normal events, usually plant transients, which can be coped with by the plant protection systems and normal plant systems but which could have the potential to damage the reactor if some additional malfunction should happen. Their typical frequency of occurrence may be more than 10 year Some of the anticipated occurrences (PIEs - postulated initiating events) are due to the increase of reactor heat removal (as might occur for an inadvertent opening of a steam relief valve, malfunctions in control systems, etc.). Some are due to the decrease of reactor heat removal (such as for feed-water pumps tripping, loss of condenser vacuum and control systems malfunctions). Some are due to a decrease in reactor coolant system flow rate, as in the case of a trip of one or more coolant pumps. Some are connected with reactivity and power distribution anomalies, such as for an inadvertent control rod withdrawal or unwanted boron dilution due to a malfunction of the volume control system for a PWR. Events entailing the increase or decrease of the reactor coolant inventory may also happen, due to malfunctions of the volume control system or small leaks. Finally, releases of radioactive substances from components may occur. 

AR340 1.53 Application of the single-failure criterion to nuclear power plant protection systems,... 

Sufficient and reliable means of commnnication should be provided to enable information and instructions to be transmitted between locations to support the operator actions during normal operation and recovery following accidents. This would include communications between the main or emergency control rooms and operating personnel at remote locations who may have to take actions affecting the state of the plant, and with off-site organizations in accident situations. The means of communication should be available under all relevant accident conditions and should not interfere with the plant protection system. 

Plant protection system X Individual signal processmg system for two reactor shutdown system... 

Two types of plant protection system are provided, the neutron detector installed on the outside of the reactor vessel and the core outlet temperature detector in the reactor vessel. 

The Plant Protection System (PPS) consists of the Reactor Protection System (RPS) and the Engineered Safety Features Actuation System (ESFAS) (see CESSAR-DC Section 7.1.1.1). 

New design features (e.g., relocating emergency feedwater tanks to protected areas, increasing the monitoring, separation and independence of plant protection systems, providing additional back-up sources of power) which provide countermeasures to sabotage must be consistent with plant safety requirements. 

Designing the Nuplex 80+ instrumentation and controls to incorporate semi-automated and on-line testing features for the Plant Protection System and on-line monitoring of fluid and electrical systems, thus enhancing the detection of sabotage. 

Was the priority operator versus plant protection system logic clearly defined and accepted at appropriate levels ... 

Reventing system, emergency prower supply, reactor vessel including internals, rotating reactor shield plug, primary and secondary heat transfer systems, plant protection system... 

The major functions and architecture of a Nuclear Power Plant Protection System are designed to meet the safety issues. Both the analogic and the digital designs are able to satisfy the requirements. 

Emergency DC Power System (Batteries) Batteries are required at the early stage of accidents to operate plant protection system including valves of SDHS... 

Diagnostic coverage is the ratio of safely controlled faults to all possible faults from Steven E Smith Fault Coverage in Plant protection Systems, ISA 1990 Paper 90-363. 

This material references part of a useful paper on reliability analysis by Steven E. Smith Fault coverage in plant protection systems, published in ISA technical papers, Volume 21, 1990. 

The extent to which plant protection systems and reactor protection systems are required to function ... 

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