Tempered coolant

As an alternative to Item 5, one may use a recirculating coolant system ( tempered coolant) with condensate temperature control of makeup coolant. This keeps the condenser dynamics constant and eliminates the problem of retuning the controller as the load changes (see Figure 3.9). 

It eliminates problems with high-fieezing-point condensate that might plug the condaiser if oncc-throu coolant were u. In extrane cases tempered coolant is taken from and returned to a simply tank that is tonperature controlled... 

Qualitatively the condenser with well-mixed (tempered) coolant is discussed in Chapter 3, Section 9 (see Figure 3.19). A mathematical analysis of its dynamics is given in Chapter 24 of reference 1. We will not repeat it here, but it leads to Ae following results (simplifying assumptions are the same as in the previous section) ... 

This method of controlling pressure, although once popular, has fallen into some disfavor in recent years. This is particularly true for once-through coolant. Since its flow rate cannot be allowed to go too low—which would lead to fouling as well as excessive exit coolant temperatures, which, in turn, contribute to corrosion—it permits only limited control of pressure. Tempered coolant, which avoids these problems, is a better choice for column pressure control via coolant flow manipulation. 

Even plant cooling water can present a seasonal problem. Wnter temperatures are often low enough to make hydrate formation possible. It is then necessary to limit the temperature of the water used on the chlorine cooler. This is usually done by arranging for series use of the water in more than one service or by tempering it with a warmer stream. Often, the latter approach uses some of the water issuing from the exchanger itself, recycled to the feed point under temperature control. Cocurrent flow of gas and coolant also can reduce the probability of hydrate formation. 

In the course of the operation of pressurized as well as of boiling water reactors, a contamination layer consisting of the oxides of primary circuit materials is formed on all surfaces which are in contact with reactor coolant. In high-temper-... 

Tempering the sliders directly which means to provide recesses for elastic coolant hoses. 

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