Abstract: This paper introduced the first application of enriched boric acid in a third generation PWR unit, and the water chemistry control strategy with higher and constant pH_t value (7.20) of the reactor coolant from the beginning of the cycle is realized through its application, which plays an important role in reducing primary material corrosion and radiation source term control. Field application practice shows that through the implementation of the above mentioned water chemical control strategy, the corrosion rate and release of primary metal materials, especially nickel in the steam generator tubes is reduced to a lower level, which is a benefit to ensuring the integrity of the second barrier and controlling of activated corrosion products and finally achieving the goal of minimizing the exposure dose to personnel.

Key words: pressurized water reactor, radiation source term, enriched boric acid, water chemistry control strategy, nickel-based alloys, corrosion, Co-58