Alternative embrittlement indexing method through application of master curve method to weld metal fracture toughness data in the transition range
- Framatome Technologies, Lynchburg, VA (United States)
Neutron-irradiation of the structural steels and weld metals that are used for reactor vessels can cause the fracture toughness of these materials to decrease. Procedures for determination of the extent of this embrittlement are in US Nuclear Regulatory Commission (USNRC) regulations. These procedures require Charpy impact test data for determination of the state of embrittlement. The master curve method has been proven to be a very powerful tool in construction of a transition range fracture toughness curve with a very limited number of replicate specimens. This enables, for the first time, construction of a material-specific fracture toughness curve. This provides a means to verify the adequacy of the RT{sub NDT} based indexing method of the ASME code reference fracture toughness curves, K{sub Ia} and K{sub Ic}. Further, an alternative method can be developed without considering Charpy impact test data. This alternative indexing parameter could be the reference temperature defined in the proposed ASTM standard. The reference temperature parameter is a direct shift parameter obtained from fracture toughness curves. Irradiated data and analyses by Oak Ridge National Laboratory (ORNL) and the B and W Owners Group (BWOG) are presented. The current method of obtaining fracture toughness has 4 to 5 times more margin which has not previously been recognized in pressurized thermal shock (PTS) analyses.
- OSTI ID:
- 403282
- Report Number(s):
- CONF-960706--; ISBN 0-7918-1771-7
- Country of Publication:
- United States
- Language:
- English
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