SYMPOSIA PAPER Published: 09 February 2018
STP87019850035

Fracture Toughness Characterization of Irradiated Low Upper-Shelf Welds

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Some welds made with Linde 80 flux and containing a high copper impurity level have exhibited postirradiation Charpy upper-shelf energy levels below 68 J (50 ft · lb). The J-R curve behavior of seven such low upper-shelf welds has been characterized in the ductile upper-shelf regime in both the preirradiation and the postirradiation conditions with fluences of ~1 × 1019 neutrons (n)/cm2 (E > 1 MeV). With the single specimen compliance (SSC) technique, these J-R curves were determined from compact toughness (CT) specimens ranging from 12.7 to 101.6-mm thick, over a temperature range of 75°C to 288°C.

For these reactor vessel steels exhibiting low upper-shelf energy levels, the J-R curves were shown to follow a power-law relationship for small crack extensions, that is, less than 2 mm. In some cases, a possible size dependence of the J-R curve has been seen, but the results are inconclusive on this point.

Correlations between J-R curve parameters (JIc and average value of tearing modulus, Tavg) and Cv upper-shelf energy have been suggested at 200°C. These findings could enhance the significance of Cv reactor surveillance data with respect to structural integrity. However, JIc and Tavg have demonstrated an inverse relationship with temperature that is not reflected by the Cv upper-shelf trend. Therefore, correlations between Cv energy and J-R curve must be adjusted to account for temperature.

Author Information

Hiser, Allen, L.
Materials Engineering Associates, Inc., Lanham, MD, US
Loss, Frank, J.
Materials Engineering Associates, Inc., Lanham, MD, US
Menke, Blaine, H.
Materials Engineering Associates, Inc., Lanham, MD, US
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Developed by Committee: E10
Pages: 1131–1149
DOI: 10.1520/STP87019850035
ISBN-EB: 978-0-8031-7679-9
ISBN-13: 978-0-8031-0592-8