Applying the Master Curve approach to a JRQ A533B Cl.1 material as part of the surveillance program of two BWR Units

•The “bias” values validated the use of the Beremin model to correct To.•The value of T0,1T,SSY = −51.5 °C validated the use of the Beremin model to correct To.•The ASME Code Case N-629 was less conservative than the current method.•MC is a viable option for NPPs that require a license extension operation for RPV.•The KJC data provides more realistic input to assess the integrity of the RPV.

Experimental measurements of the cleavage fracture toughness (KJc) of specimens were used to apply the Master Curve (MC) approach to a reference RPV steel A533B Cl.1 provided by the International Atomic Energy Agency (IAEA) as part of the surveillance programs of two BWR Units. This investigation focused on four practical issues: the effect of specimen geometry, loading rate and irradiation on the MC and the comparison of the MC to the conventional approach using Charpy data. Experiments on pre-cracked Charpy V-notch (PCCv) specimens validated the use of the Weibull model allowing correcting for the loss of constraint effect. These experiments were also used to determine the “bias” value between PCCv and standard compact tension (1T-C(T)) specimens and the effect of the loading rate on the MC. The reference temperatures indexed to T0 (RTTo and ARTTo) were directly measured and compared to the RTNDT and ARTNDT values obtained using the conventional semi-empirical approach of the American Society of Mechanical Engineers (ASME) Code, demonstrating that the latter approach was more conservative.