Abstract: The PWR primary pH is normally maintained by compounding boron acid and lithium hydroxide concentrations. Corrosion products from multiple materials served in high temperature pressurized water may deposit on the fuel surface and form CRUD. The wick boiling inside CRUD causes local enrichment of the boron acid and lithium hydroxide, and the thermal properties of the coolant inside CRUD correspondingly change. Consequently, the pH values and temperature of CRUD-fuel cladding interface will be affected. Since the temperature and pH values are key factors on localized corrosion and crack initiation and growth of fuel cladding, it is necessary to assess the effect of the pH controlling strategy on PWR fuel cladding integrity with CRUD by coupling thermal and chemical dynamics. The study results show that the highest fuel cladding integrity disable risks is corresponding to the natural boric acid and lithium hydroxide strategy, and the lowest risks are corresponding to the non-lithium hydroxide strategy.