LEAD SPECIES AND LEAD MIGRATION IN PWR SECONDARY CIRCUIT CONDITIONS

Lead behaviour, in PWR secondary circuit conditions, has been investigated in loop and laboratory experiments. Lead migration in the circuit and the possibility of removing it from the polluted surfaces were studied in tests performed in the ORION loop, designed to simulate a secondary circuit. The chemical behaviour of Pb and PbO and the solubility of PbO in water were investigated in laboratory experiments. A possible explanation of the role played by lead in stress corrosion cracking of Alloy 600 tubes is proposed.