Description and identification of difficulties arising from the application of a cleaning process in operating conditions for the treatment of components used on liquid metal fast reactors (LMFR). A technical designed approach to avoid these situations.

The cleaning process is one of the major maintenance operation for liquid metal fast reactors (LMFRs), both in operation and in their decommissioning stage. Russian and French cleaning processes are briefly described, including problems which have arisen during the processes. It appears that the cause of these problems is always connected to bad draining of the component, resulting in a vigorous reaction between vapour or liquid water and the bulk of sodium. From this discussion, the paper makes major recommendations for the efficient and safe cleaning of sodium wetted components, and proposes several processes which should be developed in order to deal with difficult situations, for example the removal of large amounts of undrainable sodium.

[Why must we manufacture vinyl chloride and polyvinyl chloride?]. / Warum müssen Vinylchlorid und Polyvinylchlorid hergestellt werden?

The manufacture of PVC is necessary for supplying the demands of modern society, for maintaining the equilibrium in the chemical industry such as the manufacture of caustic soda solution-chlorine by means of rocksalt electrolysis, and for the safe disposal of chlorine for environmental reasons. The manufacture of vinyl chloride and dichloroethane is illustrated. The conventional processing of PVC into consumer goods, after treatment of rigid and plasticized PVC compounds or granulate, is demonstrated.