Modeling of Irradiation Embrittlement and Annealing/Recovery in Pressure Vessel Steels

2009 ◽  
pp. 86-86-17
Author(s):  
RG Lott ◽  
PD Freyer
Keyword(s):  
Pressure Vessel ◽  
Irradiation Embrittlement ◽  
Pressure Vessel Steels

Irradiation Embrittlement of Advanced Pressure Vessel Steels

2008 ◽  
pp. 408-408-12
Author(s):  
KS Sivaramakrishnan ◽  
S Chatterjee ◽  
S Anantharaman ◽  
UK Viswanathan ◽  
KS Balakrishnan ◽  
...  
Keyword(s):  
Pressure Vessel ◽  
Irradiation Embrittlement ◽  
Pressure Vessel Steels

Estimation of Master Curve Based RTTo Reference Temperature From CVN Data

2005 ◽  
Author(s):  
Kim R. W. Wallin ◽  
Gerhard Nagel ◽  
Elisabeth Keim ◽  
Dieter Siegele
Keyword(s):  
Fracture Toughness ◽  
Pressure Vessel ◽  
Brittle Failure ◽  
Master Curve ◽  
Simple Relation ◽  
Systematic Evaluation ◽  
Data Sets ◽  
Irradiation Embrittlement ◽  
Pressure Vessel Steels ◽  
Asme Code

The ASME code cases N-629 and N-631 permits the use of a Master Curve-based index temperature (RTTo ≡ T0 + 19.4°C) as an alternative to traditional RTNDT-based methods of positioning the ASME KIc, and KIR curves. This approach was adopted to enable use of Master Curve technology without requiring the wholesale changes to the structure of the ASME Code that would be needed to use all aspects of Master Curve technology. For the brittle failure analysis considering irradiation embrittlement additionally a procedure to predict the adjustment of fracture toughness for EOL from irradiation surveillance results must be available as by NRC R.G. 1.99 Rev. 2 e.g.: ART = Initial RTNDT + ΔRTNDT + Margin. The conservatism of this procedure when RTNDT is replaced by RTTo is investigated for western nuclear grade pressure vessel steels and their welds. Based on a systematic evaluation of nearly 100 different irradiated material data sets, a simple relation between RTToirr, RTToref and ΔT41JRG is proposed. The relation makes use of the R.G. 1.99 Rev. 2 and enables the minimizing of margins, necessary for conventional correlations based on temperature shifts. As an example, the method is used to assess the RTTo as a function of fluence for several German pressure vessel steels and corresponding welds. It is shown that the method is robust and well suited for codification.

scholarly journals Mechanisms and Modeling of Irradiation Embrittlement of Reactor Pressure Vessel Steels.

1998 ◽  
Vol 47 (11) ◽  
pp. 1112-1118
Author(s):  
Sumio MURAKAMI ◽  
Atsushi MIYAZAKI ◽  
Kazuki TSUGIHASHI ◽  
Mamoru MIZUNO ◽  
Morio JINCHO ◽  
...  
Keyword(s):  
Pressure Vessel ◽  
Reactor Pressure Vessel ◽  
Irradiation Embrittlement ◽  
Pressure Vessel Steels ◽  
Reactor Pressure

scholarly journals Modeling of Irradiation Embrittlement of Reactor Pressure Vessel Steels

1997 ◽  
Vol 46 (2) ◽  
pp. 124-130
Author(s):  
Sumio MURAKAMI ◽  
Kazuki TSUGIHASHI ◽  
Atsushi MIYAZAKI ◽  
Morio JINCHO ◽  
Tetsuya SUZUKI
Keyword(s):  
Pressure Vessel ◽  
Reactor Pressure Vessel ◽  
Irradiation Embrittlement ◽  
Pressure Vessel Steels ◽  
Reactor Pressure

Bayesian Uncertainty Evaluation of Charpy Ductile-to-Brittle Transition Temperature for Reactor Pressure Vessel Steels

2020 ◽  
Author(s):  
Hisashi Takamizawa ◽  
Yutaka Nishiyama ◽  
Takashi Hirano
Keyword(s):  
Transition Temperature ◽  
Test Temperature ◽  
Pressure Vessel ◽  
Credible Interval ◽  
Irradiation Embrittlement ◽  
Brittle Transition ◽  
Pressure Vessel Steels ◽  
Brittle Transition Temperature ◽  
Ductile To Brittle Transition ◽  
Reactor Pressure

Abstract The irradiation embrittlement of reactor pressure vessel steels can be predicted using the ductile-to-brittle transition temperature (DBTT) shift obtained from Charpy impact tests. For the structural integrity assessment considering irradiation embrittlement, it is necessary to set margins for various uncertainties. It is important to understand what and how much factors contribute to the uncertainty. In the present study, a 34% credible interval value of Charpy DBTT at a 41J energy level (T41J) was evaluated by estimating the probability distributions of Charpy test data using Bayesian statistics. To fit the Charpy transition curves, a hyperbolic tangent with coefficients whose uncertainties depend on the test temperature was used. The probability distribution of T41J was estimated using Monte Carlo sampling and Bayesian inference. It was clarified that 34% of the credible-interval values of T41J before and after irradiation unchanged for base and weld metals when the number of specimens and test temperature were equivalent under un-irradiated and irradiated conditions. When the Charpy transition curve was determined by 12 specimens loaded in a surveillance test capsule, the estimated uncertainty of T41J was about 5 °C.

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