What factor guides the pH adjustment in PWR demineralizer operation?

• A. Boron concentration
• B. Temperature
• C. Pressure
• D. Chloride concentration

Answer: (A)

In a PWR, the primary coolant is borated water, so boron content directly influences the solution’s acid–base balance. Boric acid in the coolant sets how acidic or basic the water is, and this pH needs to stay within a tight range to protect materials and ensure proper resin performance in the demineralizers. Because of that, the pH adjustment is guided by the boron concentration: as boron levels are managed, the pH moves within the desired window, with base or acid additions chosen to keep boron in spec and the pH in the safe range.

Temperature, pressure, and chloride levels matter for overall chemistry and corrosion risk, but they aren’t the primary driver used to set the pH target in this context.