The design of components in the water-steam cycle of conventionally fired power plants is carried out according to the principles of strength theory, considering the specifications for the operation of plants. This considers the loads caused by mechanical stresses. As repeated cases of damage have shown, the interaction of liquid medium, material and alternating mechanical stress must be considered. In the case of pronounced operational stress or strain changes, unexpected damage has repeatedly occurred despite formal compliance with the permissible stresses, which in recent decades and to this day has repeatedly led to serious damage with high downtime and replacement costs in fossil fuel power plants and, until the 1990s, also repeatedly in nuclear power plants. One of the reasons for this is that mechanical nominal stresses can still be determined relatively easily with knowledge of the geometry and load. The determination or measurement devices for recording of strain rates in systems and components is much more demanding and is generally not part of the usual scope of operational monitoring. Non-destructive testing to determine damage caused by these mechanisms is challenging, too.

This shows that the damage mechanisms, which in the Anglo-American language area are recorded under the generic term of environmentally assisted cracking, were detected comparatively late on the real component. The three leading damage phenomena in the water-steam cycle are strain induced corrosion cracking (SICC), stress corrosion cracking (SCC) and corrosion fatigue (CF), more recently designated as environmentally assisted fatigue (EAF).

This technical-scientific report focuses on strain induced corrosion cracking (SICC). This mechanism forms the transitional area between stress corrosion cracking and corrosion fatigue cracking. A distinction is important to be able to define effective monitoring and remedial measures.

VGBE-TW-532e: Strain induced corrosion cracking in fossil-fired power plants - State of knowledge, operating experience, testing and integrity concepts for findings.

134 S., Abb., Tab. (2024), vgbe energy e.V. und vgbe energy service GmbH, Essen, Germany
This vgbe-Standard is available in German and English. / Dieser vgbe-Standard liegt in Deutscher und Englischer Sprache vor.
ISBN 978-3-96284-366-3 (print, English) 
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ISBN 978-3-96284-364-9 (print, German)
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