This paper deals with determination of the failures causes of supporting tubes in a 350 MW fossil fuel power plant. Due to frequent fractures of supporting pipes occurring always at the same location and the ensuing reduction of the plant availability as well as substation financial losses, there was an urgent need to resolve the problem [K. Takahashi, M. Yokouchi, S.K. Lee, K. Ando, J. Am. Ceram. Soc., 86-12, 2003]-[
]. This work describes the test results and the conclusions drawn from the results.