The solubility of iron and nickel from a nonstoichiometric nickel ferrite in a hydrogen-containing aqueous solution of 0.2 M boric acid was determined in a flow system between 330°C (626°F) and room temperature. The data are relevant to the dissolution and precipitation of corrosion products from the primary coolant system surfaces in pressurized water reactors during operation and cooldown. Solubility maxima of 4.2 ppm iron and 1.0 ppm nickel were obtained at 80°C (175°F). The results are shown to be consistent with published data for iron from magnetite in hydrochloric acid at the same pH between 330 and 120°C, but to be lower by a factor of 106 at room temperature. The low solubility in the low-temperature region suggests that a quasi-equilibrium can be established with a borated surface that passivates the ferrite substrate.