international Atomic Energy Agency IWGGCR/18 INTERNATIONAL WORKING GROUP ON GAS-COOLED REACTORS HIGH TEMPERATURE METALLIC MATERIALS FOR GAS-COOLED REACTORS PROCEEDINGS OF A SPECIALISTS MEETING ORGANIZED BY THE INTERNATIONAL ATOMIC ENERGY AGENCY AND HELD IN CRACOW, 20-23 JUNE 1988 INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA, 1989