Reliable steam generator

The serious development of WT boilers began in the mid-1850s, and by the late nineteenth century WT boilers were considered safe and reliable steam generators, able to be used for all manner of applications, both in the industrial world and for marine duty. 

In addition to securing an adequate and reliable steam generation and delivery system, the work during this stage included the following ... 

Potential for improved economy through simplification of the secondary system Elimination or simplification of the secondary system can be easily achieved by adopting a highly reliable steam generator ... 

A feature of corrosion studies which has been stressed recently (2) is the complete failure of laboratory tests on their own to predict how reliable operation of some nuclear steam generators can be maintained. At least a part of this problem is likely to arise from different redox and/or pH conditions imposed by the solution in autoclave tests and in plant conditions and many low level contaminants could be involved. In view of what has been said earlier concerning the role of Mo(VI) in stagnant water it is clear that some data, at least on the thermodynamics of aqueous Mo species, should be sought at high temperatures. 

The Uhde reformer is top-fired and has a proprietary "cold" outlet manifold system to enhance reliability. Heat recovery utilizes process heat for high-pressure steam generation, feed preheat and for heat required in the fractionation section. 

Power Production. Steam cycles for generation of electric power use various types of boilers, steam generators, and nuclear reactors operate at subcritical or supercritical pressures and use makeup and often also condensate water purification systems as well as chemical additives for feedwater and boiler-water treatment. These cycles are designed to maximize cycle efficiency and reliability. The fuel distribution of sources installed in the United States from 1990—1995 are as follow coal, 45% combined cycle, 27% miscellaneous, 14% nuclear, 11% solar, oil, and geothermal, 1% each and natural gas, 0.3%. The 1995 summer peak generation in the United States was 620 GW (26). The combined cycle plants are predominantly fired by natural gas. The miscellaneous sources include bagasse, black liquor from paper mills, landfill gas, and refuse (see Fuels frombiomass Fuels fromwaste). 

Catalyst activity was usually measured in a bench test assembly (Figure 1). The reactor included a preheat section containing tabular alumina just above (upstream from) the 30 cm3 of catalyst in the center of the reactor. Water was pumped by a minipump (Milton-Roy) to the steam generator. From a three-temperature profile around the catalyst bed, it was determined that the midpoint data were most useful and reliable. The analytical equipment consisted of an infrared device (Mine Safety Appliances) for carbon monoxide, a flame ionization detector (Beckman) for hydrocarbons, and a paramagnetic oxygen analyzer (Beckman). The entire assembly except for Telex printer and computer is pictured in Figure 2. 

Nuclear energy is not reliable because of major, unplanned repairs (e.g., steam generator replacement). 

Two concepts of a He - He intermediate heat exchanger for a heat rating of 125 - 170 MW have been selected. For both, a 10 MW test plant has been operated in the KVK loop verifying the operation of reformers with convective helium. A 10 MW decay heat removal system cooler, hot gas ducts including insulation and liner, hot gas valves, and a steam generator were other components of the KVK loop. Furthermore, a helium purification system was operated in a bypass of the main system. Starting in 1982, the KVK facility was operated for 18,400 h with approx. 7000 h above 900 C [28]. Hot gas duct with internal insulation was operated at temperatures up to 950 °C. The KVK experimental loop has demonstrated reliability and availability even of newly developed components. 

A modem steam generator, individually, and the installation, as a whole, are provided with control and automation systems and with proper shielding. These support systems are designed to insure reliable and safe performance, efficient use of fuel and of electric energy, the maintenance of... 

Steam generators (SGs) are generally regarded as the most critical of all sodium system components. Design, manufacture and experimental testing should be carried out with special case. It seems that all was done to install reliable SGs in prototype, demonstration and semicommercial LMFRs. Three prototype fast reactors (BN-350, Phenix and PFR) were commissioned in the 1960s and two of them (BN-350 and PFR) had unforeseen occurrences with SG. 

Cost reduction and reliability improvement studies have been performed to select the steam generator concept for EFR. An integral unit of 600MW(th) has been verified as favourable based on successful operating feedback from the SPX SGs. The advanced SG for EFR is a once-through straight-tube unit, without welds in the long (33,3m) tubes with tube to the tubeplates weld at each end. 

This is probably due to the fact that, apart from the control of reactivity and the protection of the steam generators, the accidental transients on fast reactors are much slower than those on the PWRs and that there are therefore fewer systems and actuators requiring both very fast and very reliable start-up. 

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