Impurities and oxygen control in lead alloys J.-L. Courouau a, * , P. Trabuc a , G. Laplanche a , Ph. Deloffre b , P. Taraud a , M. Ollivier a , R. Adriano a , S. Trambaud a a Commissariat  a l’Energie Atomique, CEA Cadarache, Centre d’ etudes de Cadarache, 13108 Saint Paul lez Durance cedex, France b CEA Saclay, 91191 Gif sur Yvette cedex, France Abstract The control of the impurities is of major interest for ensuring adequate and safe operation of lead alloys facilities from the viewpoint of the corrosion phenomenon. Specific methods have to be implemented for effective control of the liquid lead–bismuth eutectic quality to the required specifications, as for instance: dissolved oxygen monitoring, dip sampling system, analytical techniques for impurities measurement. Even though the oxygen control in the static facility BIP proved difficult, a better knowledge of kinetics behaviour of the oxygen is acquired. Oxygen sensors gave results in agreement with the theory during the tests achieved on the BIP and on the COLIMESTA facilities. The dip sampler was validated on static device: it allows an effective sampling of the liquid metal melt and an easy separation of the melt from the sampling device when cold. The set of analytical techniques for the measurements of metallic impurities is efficient as well, except for the nickel element, for which the method of analysis with atomic absorption spectroscopy coupled with spiking method should allow the lower detection limit to be decreased below the 5 lg/g as for the iron impurity. Ó 2002 Elsevier Science B.V. All rights reserved. 1. Introduction Lead and lead–bismuth eutectic (LBE) are studied worldwide as spallation targets in accelerator driven system (ADS), in which high energy protons collide with lead throughout a window to produce 15–20 fast neu- trons by the spallation reaction. These neutrons might be used either in sub-critical power reactor systems, that present an intrinsic safety quality, or in the long-lived actinides transmutation system in the framework of the nuclear waste management. The latter option is cur- rently under study in France within the 1991 law on nuclear wastes management. Besides, the lead alloy can be used as a primary coolant, but unlike the liquid so- dium, used as coolant in fast reactors worldwide, lead alloys are not compatible with any steel, inducing spe- cific requirements for corrosion protection implementa- tion and for liquid metal quality control, in order to ensure adequate and safe operations. The control of oxygen and impurities in LBE is then a challenge for both corrosion control (ensure steel protection, ...) and quality control (avoid slag’s formation, limit circuits contamination, ...), that is one of the key issue for any lead alloy system. Specific methods must be imple- mented for the effective control of the liquid LBE quality to meet the required specifications, such as dissolved oxygen monitoring, dip sampling system, and analytical techniques for impurities measurements. 2. Oxygen monitoring in lead–bismuth eutectic A typical electrochemical cell puts in contact two different media throughout a solid electrolytic bridge which presents pure ionic conduction. One of the me- dia is called the reference, as its function is to provide a constant oxygen thermodynamic activity. The other is the liquid LBE, for which the dissolved oxygen Journal of Nuclear Materials 301 (2002) 53–59 www.elsevier.com/locate/jnucmat * Corresponding author. Tel.: +33-4 42 25 32 66; fax: +33-4 42 25 72 87. E-mail address: jean-louis.courouau@cea.fr (J.-L. Cou- rouau). 0022-3115/02/$ - see front matter Ó 2002 Elsevier Science B.V. All rights reserved. PII:S0022-3115(01)00726-7