Which term describes the impurities such as dissolved oxygen, sodium, chloride, pH, and corrosion products in a plant's secondary system?

• A. Secondary System Impurities
• B. Feedwater Contaminants
• C. Primary Circuit Materials
• D. Vapor Space Pollutants

Answer: (A)

In this context, the term describes impurities on the steam and condensate side of the plant—the secondary system. Dissolved oxygen, sodium, chloride, and pH are all factors that affect corrosion and materials stability in that system, and corrosion products are the byproducts that circulate there. Grouping them as secondary system impurities emphasizes that they are problems within the secondary loop, not just in the feedwater input or in the primary circuit. Feedwater contaminants would be limited to impurities present in the water entering the boiler, which is a narrower category than the entire secondary system’s impurities.