Boilers steam-generator circulation system

Steam-Generator Circulation System Circulation systems for utility application are generally classified as natural circulation and forced or pump-assisted circulation in drum-type boilers, and as once-through now in subcritical- and supercriticaf-pressure boilers. The... 

The boiler steam-water circulation system is designed to promote the delivery of steam from the various generating tubes to the boiler steam drum (top drum). From here the steam is separated from the BW and transferred to the steam delivery system for possible superheating and subsequent use in a turbine generator or other downstream process application. 

NOTE Although superheater, reheater, and economizer heat exchangers all contain either steam or water in their respective tube bundles, they generally are not considered by boiler engineers and designers to be part of the steam-water circulation system s boiler surfaces. This distinction typically is reserved for the various tubes, connecting headers (manifolds), and drums that collectively provide the primary heat transfer and steam-generating facility. 

Boiler Design Issues Boiler design involves the interaction of many variables water-steam circulation, fuel characteristics, firing systems and heat input, and heat transfer. The furnace enclosure is one of the most critical components of a steam generator and must be conservatively designed to assure high boiler availability. The furnace... 

WWER-lOOO/V-392 (Russia) This reactor incorporates an important passive system to remove core decay heat in case of station blackout (so called SPOT). The SPOT system consists of four groups of closed natural circulation circuits, hi the ribbed tubular air-cooled heat exchanger (four heat exchangers for each circuit), steam extracted from the steam generator condenses, and the condensate flows by gravity to the steam generator boiler water volume. Under normal plant operation, the SPOT system is under standby. In the case of plant... 

Nuclear Boiler Assembly. This assembly consists of the equipment and instrumentation necessary to produce, contain, and control the steam required by the turbine-generator. The principal components of the nuclear boiler are (1) reactor vessel and internals—reactor pressure vessel, jet pumps for reactor water circulation, steam separators and dryers, and core support structure (2) reactor water recirculation system—pumps, valves, and piping used in providing and controlling core flow (3) main steam lines—main steam safety and relief valves, piping, and pipe supports from reactor pressure vessel up to and including the isolation valves outside of the primary containment barrier (4) control rod drive system—control rods, control rod drive mechanisms and hydraulic system for insertion and withdrawal of the control rods and (5) nuclear fuel and in-core instrumentation,... 

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