Analysis of long-term durability of prestressed tendons in Swedish nuclear reactor containments 2021.

The statistical methods based on confidence interval were used to evaluate the meaningfulness of the observed trends in material embrittlement. A literature study concerning possible phenomena behind the material degradation was performed. In the second stage of the project experiments on mechanical performance, chemical composition and the microscopic analysis of selected wires was performed to validate the findings of statistical analysis. The new results did not confirm the trends observed in the historical data in uniaxial tensile test. The chemical and microscopic analysis did not indicate any material degradation. The fracture of new tests had typically ductile character, however the samples treated with hydrogen subjected to reversed bend test exhibited embrittlement on the surface. The project is concluded with reflection on the used testing methods and possible procedures to ensure reliability of the experimental results in the future, as well as, possible further research in the steel embrittlement.

This report was completed in 2021. The findings and references to websites and other research, etc., have not been updated since then. However, we consider the report to be of such interest that we have decided to publish it despite it being five years old.