DOE-HDBK-1015/2-93Principles of Water TreatmentDISSOLVED GASES, SUSPENDED SOLIDS, AND pH CONTROLRev. 0CH-04Page 15DISSOLVED GASES, SUSPENDED SOLIDS,AND pH CONTROLThe presence of dissolved gases, suspended solids, and incorrect pH can bedetrimental to the water systems associated with a reactor facility. Therefore,these conditions must be minimized or eliminated to reduce corrosion in thesystems of the facility. The way these conditions are controlled and thedifficulties in controlling them are discussed in this chapter.EO 1.6EXPLAIN the three basic methods used to remove dissolvedgases from water.EO 1.7LIST five filtration mediums used to remove suspendedsolids from water.EO 1.8EXPLAIN how mixed-bed ion exchangers may be used tocontrol pH.EO 1.9DISCUSS resin malfunctions, including the following:a.Channelingb.Breakthroughc.ExhaustionRemovalofDissolvedGasesDissolved gases result from different sources depending upon which system we examine. In thefollowing discussion, we will address makeup water, reactor coolant systems, secondary facilitywater systems, the sources of dissolved gases, and methods used to reduce their concentrationsto acceptable levels.Many facilities use raw water as a source for makeup water systems. Pretreatment of this wateris accomplished in various ways from distillation to a series of distinct processes as shown inFigure 5. In a pretreatment system similar to that shown in Figure 5, a resin column containinga cation resin (hydrogen form) is used to remove cations. The water entering the cationexchanger contains numerous ions including sodium (Na ), bicarbonate (HCO ), and others+-3(HCO is one of the major impurities in many raw water systems). Na ions result from the3-+water softener located upstream in the pretreatment system. In addition to the HCO ions, raw3-water contains large amounts of magnesium (Mg ) and calcium (Ca ), as well as small amounts++++of other ionic impurities.
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