Secondary systems

Secondary System. The water quality specifications for the feedwater and blowdown water in a recirculating steam generator (RSG) and the ... 

The pH is plant specific, depending on additive used and secondary system materials. Feedwater generally should be equivalent to pH = 9.3 at 25°C for ammonia and carbon steel equipment. 

Our present discussions relate only to the laboratory testing of safety-related secondary systems, as are employed in critical areas such as areas of emergency power supply and reactor power control supply etc. of a nuclear power plant (NPP) according to IEEE 344 and lEC 60980. There are other codes also but IEEE 344 is referred to more commonly. Basically, all such codes are meant for an NPP but they can be applied to other critical applications or installations that are prone to earthquakes. 

Hydro projects, dams, bridges, naval equipment and any installations that aie prone to continuous shocks and vibrations also require their primary and secondary systems to have a better design and operational ability to withstand seismic effects or other ground/surface vibrations. No specific tests are presently prescribed for such applications. But response spectra can be established even for such locations and the primary and secondary systems analysed mathematically or laboratory tested. 

To test large to very large objects such as primary systems, where a laboratory test is not practical, seismic checks are established through analytical means. Similarly, for very large and heavy secondary systems such as turbines, alternators or transformers and reactors also their... 

Since the studies under discussion have cost estimates factored from major material, secondary systems at this stage have relatively smaller impact than later when more definitive cost estimates are done. At this stage, it is well to gain a feel for the completeness of the licensor s design with respect to secondary systems. 

Another problem often noticed once the plant is built is incompatibility of materials (heat exchangers, tubing fittings, pipe valves and fittings, etc.) within the purchased secondary systems package with materials in the main plant. Quite often, equipment such as condensers... 

Kerridge has provided an excellent article on the interface betw een the operating company and the contractor to define all requirements in complete and standardized detail. This includes who is responsible for every deliverable. The operating company and contractor must work as a team. An example of one area that needs to be reviewed often with the contractor is the provision of secondary systems as packages, perhaps from a third party. Such systems can easily become orphans. This problem is discussed in the Process Definition section of Chapter 16. 

For MTHW and HTFIW systems, heat emitters may be as for LTFIW systems, except that, for safety reasons, units with accessible surfaces at water temperature would not normally be employed. Embedded panel coils may be used in conjunction with a MTHW or HTHW distribution system, with insulating sleeves around the coil piping to reduce the heat flow. Alternatively, the coils can be operated as reduced temperature secondary systems by allowing only a small, carefully controlled proportion of flow temperature water to be mixed with the water circulating in the coils. 

Design arrangements for reduced-temperature secondary systems (sometimes referred to as injection circuits) include fixed provisions for minimum dilution rates. Conventional system-balancing devices with three-port automatic modulating valves to regulate mixed water temperatures and, hence, heat output are used. Automatic safety controls must prevent excessive temperatures occurring in the coil circuits, as floor fabrics or finishes could be damaged very rapidly. 

Regioselective bromination of phenols gave 2-bromo-, 4-bromo-, 2,6-dibromo-, 2,4-dibromo, 2-bromo-6-substituted, 4-bromo-2-substituted and 2,4-dibromo-6-substitutgd phenols, respectively. Especially, 2-bromo-, 2,6-dibromo- and 2-bromo-6-substituted phenols which were prepared via long steps, were obtained in NBS-amine (primary and secondary) system in high yields under ordinary conditions. The scope and their mechanisms were discussed. 

Element Primary system (ppm) Secondary system (ppm) Method of analysis... 

Trimethylsilyl iodide (TMSI) cleaves methyl ethers in a period of a few hours at room temperature.89 Benzyl and f-butyl systems are cleaved very rapidly, whereas secondary systems require longer times. The reaction presumably proceeds via an initially formed silyl oxonium ion. 

If bridged intermediates are involved, the larger steric bulk of secondary systems would retard the reaction. Steric restrictions may be further enhanced by the fact that organomagnesium reagents are often present as clusters (see below). 

From these reasons, almost large snow cooling systems adopted indirect heat exchanging system. In indirect system, a water-water-type heat exchanger is used between primary and secondary system. Figure 186 shows an application of direct heat exchange system. 

A set of curved tube or coil in which refrigerant or glycol solution run is installed in a tank and cooled inside of the coil. Ice is formed on the surface of the coil and melted from boundary between ice and water. Stored heat is usually recovered by supplying water directly to secondary system. Some systems use heat exchanger to reduce water head loss. This type of ice storage... 

Landfills have two LCRSs a primary LCRS and a secondary LCRS. Any leachate that penetrates the primary system and enters the secondary system must be removed. Vertical standpipes are used... 

The design of a waste treatment system requires data that was not available to me. A secondary system to reduce the biological oxygen demand and a tertiary system to at least remove most of the phosphates are required. Whether styrene is biodegradable was not known. If it is not, then the tertiary system will have to be designed to remove it also. 

A hydroxyl group one or two carbons further removed, y or 5 to the fluorine substituent, does not influence the fluorine chemical shift significantly (Scheme 3.22). In the case of a secondary system, the fluorine is also unaffected by a y-hydroxy substituent. 

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