TECH UTILITIES 2.O CRACK CRACK
This paper introduces studies of the effects of different thermal loading cycles to crack opening and residual stress state as seen at the surface of the sample and in the ultrasonic signal. These cracks can be used to simulate behaviour of realistic cracks under service conditions. The method produces true fatigue cracks, which are representative of most service-induced cracks. Hänninen, H.Īdvanced artificial flaw manufacturing method has become available. The role of carbon and chromium and intergranular precipitates on IGSCC is discussed.Īdvanced Flaw Manufacturing and Crack Growth Control The distribution of oxygen near a crack in material tested with respect to IGSCC was also investigated. Applied microanalytical techniques allowed direct measurement of carbon concentration in the matrix together with determination of grain boundary micro structure and microchemistry in all material conditions. The materials were also tested with respect to their resistance to intergranular stress corrosion cracking ( IGSCC) in high-purity water at 365 °. The microstructure in six commercial batches of alloys 600 and 690 has been investigated using scanning electron microscopy (SEM), analytical transmission electron microscopy (ATEM), atom probe field ion microscopy (APFIM), and secondary ion mass spectroscopy (SIMS). Stiller, Krystyna Nilsson, Jan-Olof Norring, Kjell Structure, chemistry, and stress corrosion cracking of grain boundaries in alloys 600 and 690 The technical basis for zinc addition to the BWR coolant will also provided along with an in-plant example of the most severe water chemistry transient to date. More specifically, the effects of typical BWR ionic impurities (e.g., sulfate, chloride, nitrate, borate, phosphate, etc.) on IGSCC propensities in both NWC and HWC environments will be discussed. The goal of this paper is to present the technical basis for controlling various impurities under both oxygenated, i.e., normal water chemistry (NWC) and deoxygenated, i.e., hydrogen water chemistry (HWC) conditions for mitigation of IGSCC. IGSCC can be further accelerated by the presence of certain impurities dissolved in the coolant. However, even the utilization of near theoretical conductivity water cannot prevent intergranular stress corrosion cracking ( IGSCC) of sensitized stainless steel, wrought nickel alloys and nickel weld metals under oxygenated conditions. Technical Basis for Water Chemistry Control of IGSCC in Boiling Water Reactorsīoiling water reactors (BWRs) operate with very high purity water.
From that experience he extracts some knowledge about this cracking (influence of chemistry in the environment, stress state, crack growth rate, and occurrence in laboratory condition of break before leak).
TECH UTILITIES 2.O CRACK GENERATOR
The author presents his experience in manufacturing IGSCC realistic defects, mainly in INCONEL 600 MA Steam Generator Tubes.