TY - GEN
T1 - Environmentally assisted fatigue assessment considering an alternative method to the asme code CASE N-792
AU - Courtin, Stéphan
AU - Lefrançois, André
AU - Le Duff, Jean Alain
AU - Le Pécheur, Anne
PY - 2012/1/1
Y1 - 2012/1/1
N2 - The conservatism of the austenitic stainless steel fatigue design curve has been severely questioned since the release of the NUREG/CR-6909 document [1] where a new methodology to assess environmentally assisted fatigue (EAF), including also a new in-air fatigue design curve, have been proposed. In the same way, the ASME Code Case N-792 [2] suggests calculating EAF usage factors via the multiplication of the in-air fatigue usage factors by Fen penalty factors, this resulting in a significant increase of these parameters. In this context, AREVA NP SAS has performed, for several years, its own Pressurized Water Reactor (PWR) Low Cycle Fatigue (LCF) test program to better identify environmental effects in representative industrial conditions [3]. Among others, these experimental works have pointed out the over-conservatism of the NUREG/CR-6909 design approach. From these results, AREVA NP SAS has developed an alternative EAF assessment method which has been approved by the Finnish Nuclear Safety Authority [4]. This paper proposes to give an overview of this approach and to illustrate it on an EAF EPRI sample problem [5].
AB - The conservatism of the austenitic stainless steel fatigue design curve has been severely questioned since the release of the NUREG/CR-6909 document [1] where a new methodology to assess environmentally assisted fatigue (EAF), including also a new in-air fatigue design curve, have been proposed. In the same way, the ASME Code Case N-792 [2] suggests calculating EAF usage factors via the multiplication of the in-air fatigue usage factors by Fen penalty factors, this resulting in a significant increase of these parameters. In this context, AREVA NP SAS has performed, for several years, its own Pressurized Water Reactor (PWR) Low Cycle Fatigue (LCF) test program to better identify environmental effects in representative industrial conditions [3]. Among others, these experimental works have pointed out the over-conservatism of the NUREG/CR-6909 design approach. From these results, AREVA NP SAS has developed an alternative EAF assessment method which has been approved by the Finnish Nuclear Safety Authority [4]. This paper proposes to give an overview of this approach and to illustrate it on an EAF EPRI sample problem [5].
U2 - 10.1115/PVP2012-78088
DO - 10.1115/PVP2012-78088
M3 - Conference contribution
AN - SCOPUS:84882971321
SN - 9780791855003
T3 - American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP
SP - 147
EP - 153
BT - ASME 2012 Pressure Vessels and Piping Conference, PVP 2012
PB - American Society of Mechanical Engineers (ASME)
T2 - ASME 2012 Pressure Vessels and Piping Conference, PVP 2012
Y2 - 15 July 2012 through 19 July 2012
ER -