Embrittlement prediction curve

The Russian predictive embrittlement method is based primarily on test reactor data and utilizes the shift in CVN impact energy properties essentially at the 47 J temperature (PNAE, 1989). The effects of Cu, P and O (E > 0.5 MeV) are included in the method. A new local approach called the Unified Curve (similar to the Master Curve method) for assessing vessel integrity has recently has been added for structural analysis purposes (Margolin et ai, 2007). Additionally, an IAEA activity on embrittlement prediction for WWER-440 RPVs was completed (IAEA, 2005), with the published IAEA report providing recommended guidelines based on a larger database than previously available. 

Master curves can be used to predict creep resistance, embrittlement, and other property changes over time at a given temperature, or the time it takes for the modulus or some other parameter to reach a critical value. For example, a mbber hose may burst or crack if its modulus exceeds a certain level, or an elastomeric mount may fail if creep is excessive. The time it takes to reach the critical value at a given temperature can be deduced from the master curve. Frequency-based master curves can be used to predict impact behavior or the damping abiUty of materials being considered for sound or vibration deadening. The theory, constmction, and use of master curves have been discussed (145,242,271,277,278,299,300). 

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