CORROSION-RESISTANT GRAPHITE FOR NUCLEAR APPLICATIONS - MANUFACTURINGMETHODS AND VALIDATION TESTS FOR COATINGS ON MATERIALS MADE FROM DIFFERENT GRAPHITE QUALITIES

Graphite is a multi-purpose material which is used in many conventiona l and nuclear industrial plants. It is known that graphite materials a re corroded by air flows and steam at temperatures higher than 400 deg rees C. For applications using graphite materials under these conditio ns it is proposed that the outer surface of these materials be protect ed by means of SiC coatings. In response to this, different nuclear gr aphites, such as IG 110 and A3-3 which are already used in High Temper ature Reactor plants, and commercial electrographites like FU 9512 and EK 98 were investigated. The coatings were produced by chemical vapor deposition or the paste siliconization method. For the examination of the coatings, a number of tests were carried out, more precisely, cor rosion, mechanical stress and irradiation tests. The results of these tests show that SiC coatings applied to certain graphites are corrosio n resistant and mechanically safe. So far, the visual results of the i rradiation tests indicate that the coatings are tight. Post-irradiatio n tests will be completed soon.