Reanalysis of oxide solubility data: results for nickel oxide and magnetite

The analysis of oxide solubility data in high temperature water is discussed and attention drawn to (i) the need to use self-consistent sets of thermodynamic assumptions when intercomparing different studies and (ii) the importance of writing chemical equations involving ionic solution species in the correct manner (balancing like charges) if extrapolation to temperatures outside the range over which data were acquired is to be reliable. Literature solubility data for nickel oxide and magnetite are reanalysed, paying particular attention to uncertainties in the pH of minimum solubility and the magnitude and sign of the temperature coefficient of solubility at temperatures appropriate to the PWR primary circuit, around 3000C. (U.K.)