Tensile and creep property determination of 15-15Ti fuel cladding steel by small punch testing

The integrity of the fuel cladding in present and future nuclear fuel concepts is critical for the safe perfor-mance of the power plants. The material performance of 15-15Ti (1.4970) thin walled fuel cladding tubes are presently being evaluated in the EERA JPNM pilot project TASTE. The TASTE objectives are to compare existing testing methodologies for claddings and to determine the tensile and creep properties of the 15-15Ti (1.4970) steel in the final product form. In this paper the small punch (SP) test technique is assessed in more detail for testing the 24% cold worked cladding provided by SCK·CEN. The SP test results are compared with results from tensile (axial) tube tests and ring tension (hoop) tests. It is shown that the SP tensile test can produce robust estimates on the tensile strength in the temperature range from room temperature to 800°C. The presented equation for transfering maximum force to engineering stress is shown to work for all the three test set-ups of the participating laboratories. For creep it is shown that the SP tests do not provide comparable results to internal pressure of classical creep test due to low creep ductility and premature creep cracking already at low deflections imposed at by the testing technique.

HOLMSTROM Bjorn;  SIMONOVSKI Igor;  RIPPLINGER Stefan;  ALTSTADT Eberhard;  DELVILLE Remi;  SERRANO Marta;  RADU Vasile; 

2016-11-08

VTT Technical Research Centre of Finland Ltd

JRC102350

978-951-38-8436-9,   

2242-1211,   

http://www.vtt.fi/inf/pdf/technology/2016/T261.pdf,    https://publications.jrc.ec.europa.eu/repository/handle/JRC102350,