ISSN: 1546-962X
Page Count: 12

Extrapolation of Fracture Toughness Data for HT9 Irradiated at 360–390°C
Gelles, DS
Pacific Northwest National Laboratory, WA

Kurtz, RJ

Abstract

Following irradiation in the FFTF-AC01 test at 360°C to 5.5 × 10²² n/cm², two HT9 samples tested at 30°C were measured to have fracture toughness levels of 28.2 and 31.9 MPa m^1/2, respectively, whereas a third identical specimen tested at 205°C gave 126 MPa m^1/2. 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.

Keywords:
fracture toughness, neutron irradiation, martensitic steel, master curve analysis

Paper ID: JAI12882
DOI: 10.1520/JAI12882
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