1. Swiss Federal Institute for Reactor Research Department of Metallurgy, P.O. Box CH-5303, Wuerenlingen, Switzerland
2. Hochtemperatur-Reaktorbau, Dept. TB 2 Gottlieb-Daimler-Strasse 6, D-6800 Mannheim 1, Federal Republic of Germany
3. Brown, Boveri & Cie, Ltd. Central Materials Laboratory, P.O. Box 351, D-6800 Mannheim Federal Republic of Germany
4. Interatom, Dept. T 251 Materials Friedrich Ebert Strasse, D-5060 Bergisch-Gladbach 1 Federal Republic of Germany