Environmentally Assisted Cracking Crack Initiation in Nickel-Based Alloy Dissimilar Metal Welds in Doped and Pure Steam and Pressurized Water Reactor Water

CORROSION ◽  
10.5006/2339 ◽  
2017 ◽  
Vol 73 (7) ◽  
pp. 808-821 ◽  
Author(s):  
Aki Toivonen ◽  
Hannu Hänninen ◽  
Tapio Saukkonen ◽  
Pertti Aaltonen
Keyword(s):  
Crack Initiation ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor ◽  
Reactor Water ◽  
Dissimilar Metal ◽  
Environmentally Assisted Cracking ◽  
Nickel Based Alloy ◽  
Pure Steam

scholarly journals Unstable Crack Propagation Under Severe Accident Scenario Conditions in a Pressurized Water Reactor

2009 ◽  
Author(s):  
Nicolas Tardif ◽  
Michel Coret ◽  
Alain Combesure
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Internal Pressure ◽  
Severe Accident ◽  
Pressurized Water Reactor ◽  
Crack Initiation And Propagation ◽  
Pressurized Water ◽  
Water Reactor ◽  
Initiation And Propagation ◽  
Vessel Bottom

In the case of a severe accident scenario of a pressurized water reactor which includes cracking of the vessel bottom head, it is crucial to predict the leak rate and hence the crack size for the ex-vessel accident management. We present an experimental framework to analyze the crack propagation under such severe conditions for different 16MND5 French nuclear steel grades. An original experimental setup has been designed in order to perform bi-axial tests (tensile load independent of internal pressure) at high temperatures (1180K – 1280K) on tubular test specimens. The temperature loading and the mechanical loading can be set to reproduce the stress distribution of the hemispherical vessel bottom head submitted to an internal pressure. Moreover, the test was designed to be easily transposable to the real structure in terms of crack propagation and depressurization thanks to an energy based scaling methodology. We observed the crack initiation and propagation with two high speed digital cameras. Force, internal pressure, displacement and temperature fields were also measured and synchronized with the optical measurements. The different creep stages are observed and characterized. The crack propagation and opening history have been measured. During crack initiation and propagation stages, the depressurization can be correlated with the crack geometry. Finally, the setup has been designed in order to validate future numerical analysis.

Effect of the Surface Grinding on the Environmentally Assisted Crack Initiation of 316 L Steel in Simulated Pressurized Water Reactor Water

2019 ◽  
Vol 5 (3) ◽  
Author(s):  
Anna Hojna ◽  
Mariia Zimina ◽  
Lucia Rozumova
Keyword(s):  
Microstructural Analysis ◽  
Ground Surface ◽  
Polished Surface ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor ◽  
Surface Finishes ◽  
Environmentally Assisted Cracking ◽  
Minimal Diameter

This paper presents results on the effect of a surface treatment on the environmentally assisted corrosion cracking in a pressurized water reactor chemistry. Slow strain rate testing of 316 L austenitic steel with selected rates was performed at pressurized water reactor (PWR) simulated water at 350 °C and in air at 300 °C. Detailed prior and post-testing characterization of two types of surfaces including roughness, hardness, and microstructural analysis was made. Transgranular cleavage-like environmentally assisted cracking (EAC) initiation and growth were observed under PWR conditions. The effect of two surface finishes on the cracking initiation was observed: (i) first crack initiates from the polished surface in a vicinity of the necking area rather than from the ground surface and (ii) then the deeper crack develops in the minimal diameter from the polished surface side than from the ground one.

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