Circuit steam

An important field of study for power plants is that of the combinedplant [ 1 ]. A broad definition of the combined power plant (Fig. 1.5) is one in which a higher (upper or topping) thermodynamic cycle produces power, but part or all of its heat rejection is used in supplying heat to a lower or bottoming cycle. The upper plant is frequently an open circuit gas turbine while the lower plant is a closed circuit steam turbine together they form a combined cycle gas turbine (CCGT) plant. 

O.E. ADAMOV et al, "Two-circuit Steam-Generation Facility with Fast Lead-cooled Reactor". In Lead-cooled reactor. Proc. Intern. Conf. on Fast Reactor and Related Fuel Cycles. Kyoto, Japan, 1991. 

Evaporation of secondary coolant through a pilot operated relief valve (PORV) on the secondary circuit steam pressurizer. 

Deterministic safety analysis is performed with the set of calculation codes developed by OKBM and proven in calculations of stationary and non-stationary modes of plant operation. The codes take into account specific features of the plant design, circulation circuit, steam generator, aftercooling systems, control system, etc., and are based on experimentally proven methods of calculation and correlations and have a long-term experience of application. 

The PSRD is an indirect cycle light water cooled tank-type small reactor with an integral design of the primary circuit. Steam generator is located inside the reactor vessel. The PSRD is designed to achieve system simplification, resulting in the reduction of costs for construction, operation and maintenance. The assessments of the plant economy are... 

The reactor is located in a cavity with concrete walls and is covered with a leak-tight metallic liner. The liner above the reactor cover acts a leak-tight shell under which the control rod drive mechanisms (CRDMs), drives of the primary circuit pumps and the in-reactor refuelling mechanisms are located. Secondary circuit steam generators and the pipelines of each loop are arranged in individual rooms. 

The normal heat removal system is based on a three-circuit design and includes a loop-less (pool type) primary circuit in the reactor module, two equivalent loops of the intermediate sodium circuit, two loops of the steam-water circuit and the turbo-generator facility. During normal operation, heat released in the core, including residual heat release of the shutdown reactor, is transferred to the steam-water circuit. Steam can be taken off from the third (steam-water) circuit for process applications and/ or district heating. 

Nuclear heat generated in the 181 fuel sub-assembly (FSA) is transported to four intermediate heat exchangers (IHX) in which the heat is transferred from the primary to the secondary circuit, and in turn, is transferred to the steam generators (SG). Primary sodium is circulated by two primary sodium pumps (PSP). There are eight SGs in the secondary circuit. Steam... 

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... 

Find a way to overcome the constraint while still maintaining the areas. This is often possible by using indirect heat transfer between the two areas. The simplest option is via the existing utility system. For example, rather than have a direct match between two streams, one can perhaps generate steam to be fed into the steam mains and the other use steam from the same mains. The utility system then acts as a buffer between the two areas. Another possibility might be to use a heat transfer medium such as a hot oil which circulates between the two streams being matched. To maintain operational independence, a standby heater and cooler supplied by utilities is needed in the hot oil circuit such that if either area is not operational, utilities could substitute heat recovery for short periods. 

It has developed a real time method to compare successive non-destructive inspections of the steam generator tubes in nuclear power plants. Each tube provides a safety barrier between the primary and secondary coolant circuits. Each steam generator contains several thousands of tubes whose structural integrity must be ensured through the lifetime of the plant, Therefore, Laborelec performs extensive nondestructive tests after each plant outage. 

Polysulfones also offer desirable properties for cookware appHcations, eg, microwave transparency and environmental resistance to most common detergents. Resistance to various sterilizing media (eg, steam, disinfectants, and gamma radiation) makes polysulfones the resin family of choice for many medical devices. Uses in the electrical and electronic industry include printed circuit boards, circuit breaker components, connectors, sockets, and business machine parts, to mention a few. The good clarity of PSF makes it attractive for food service and food processing uses. Examples of appHcations in this area include coffee decanters and automated dairy processing components. 

PWRs operate differendy from BWRs. In PWRs, no boiling takes place in the primary heat-transfer loop. Instead, only heating of highly pressurized water occurs. In a separate heat-exchanger vessel, heat is transferred from the pressurized water circuit to a secondary water circuit that operates at a lower pressure and therefore enables boiling. Because of thermal transfer limitations, ultimate steam conditions in PWR power plants ate similar to those in BWR plants. For this reason, materials used in nuclear plant steam turbines and piping must be more resistant to erosion and thermal stresses than those used in conventional units. 

Maintenance of isothermal conditions requires special care. Temperature differences should be minimised and heat-transfer coefficients and surface areas maximized. Electric heaters, steam jackets, or molten salt baths are often used for such purposes. Separate heating or cooling circuits and controls are used with inlet and oudet lines to minimize end effects. Pressure or thermal transients can result in longer Hved transients in the individual catalyst pellets, because concentration and temperature gradients within catalyst pores adjust slowly. 

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