Title:Reviewed Software Methodology to Stress Corrosion Prediction
VOLUME: 6 ISSUE: 1
Author(s):Omar Fernandes Aly and Miguel Mattar Neto
Affiliation:IPEN/CNEN-USP – Energy and Nuclear Research Institute, Av. Lineu Prestes 2.242-USP Campus- 05508-900 São Paulo, SP, Brasil.
Keywords:Light water nuclear reactors, modeling software, Pourbaix diagram, stress corrosion prediction.
Abstract:Background: Stress Corrosion Cracking (SCC) is a sudden and difficult-to-predict severe
degradation mode of failure of nuclear, petrochemical, and other industries. This is a review of a
development proposal for methodological software for modeling SCC based on: the failure propensity
plus a kinetic model link which better describes its evolution.
Methods: The basic issues of this methodology are: a) A fixed combination of material-environmental
condition is plotted on a potential-pH (Pourbaix) diagram marked with corrosion submodes – which
can be originated from literature and/or experimental data. This forms a Knowledge Base (KB) for
SCC-Propensity. Fuzzy Logic- a form of multiple valued logic where uncertainties can be considered - can be used to
determine the SCC-Propensity zones; b) When the actual corrosion submode of the concerning material-environment is
marked, based on new experiments, a feedback should be sent to the KB with the purpose to check the original submode
border; c) Over the determined point (or region) in a SCC submode, a proper kinetic model should be chosen (departing
for example from a kinetic library model-KB) to adjust the experimental data from the concerning material-environment.
Alternatively a new empiric or numeric model can be adjusted; d) The regression quality of the model adjusted should be
properly and statistically evaluated, and a feedback should be “fuzzylogically” retrofit its adequacy.
Results: The main result is prediction with an adequate statistical regression.
Conclusion: In this article the methodology is reviewed with an improving concerning the Pourbaix diagram construction
for multielement systems, and at high temperatures.
