SYMPOSIA PAPER Published: 01 January 2006

Extrapolation of Fracture Toughness Data for HT9 Irradiated at 360–390°C


Following irradiation in the FFTF-AC01 test at 360°C to 5.5 x 1022 n/cm2, two HT9 samples tested at 30°C were measured to have fracture toughness levels of 28.2 and 31.9 MPa m1/2, respectively, whereas a third identical specimen tested at 205°C gave 126 MPa m1/2. Based on testing of notched tensile specimens from the same irradiation test, the low toughness was a result of brittle fracture. A similar low level of toughness has also been demonstrated in HT9 following irradiation at 250°C, and therefore such behavior is reproducible. Using ASTM Standard E 1921-02, which characterizes the fracture toughness of ferritic steels that experience onset of cleavage cracking at instabilities, it is shown that these data can be analyzed by a Master Curve approach, and that the trend of the fracture toughness over a wider range of temperatures can be estimated. Master Curve analysis demonstrates that toughness will remain low over a wide range of temperatures near 30°C, but will degrade only slightly when temperatures drop to -10°C.

Author Information

Gelles, DS
Pacific Northwest National Laboratory, Richland, WA
Kurtz, RJ
Pacific Northwest National Laboratory, Richland, WA
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Developed by Committee: E10
Pages: 99–110
DOI: 10.1520/STP37571S
ISBN-EB: 978-0-8031-5518-3
ISBN-13: 978-0-8031-3401-0