There is massive assumptions going on and little science.
This seems to be related to the Areva Le Creusot forge over hydrogen flaking. Any connections to the new Framatome forge issue. Areva and Framatome are one and the same.
Mechanisms of Cracking Associated with Weld Deposited Cladding
As discussed in WCAP-15338-A [1] and repeated here, underclad cracking was initially detected in 1970, and has been extensively investigated by Westinghouse and others over the past 30 years. This type of cracking in reactor vessels has also been identified in France and Japan, in addition to the United States.
The cracking has occurred in the low alloy steel base metal heat-affected zone (HAZ) beneath the austenitic stainless steel weld overlay that is deposited to protect the ferritic material from corrosion. Two types of underclad cracking have been identified.
Reheat cracking has occurred as a result of post weld heat treatment of single-layer austenitic stainless steel cladding applied using high-heat-input welding processes on ASME SA-508, Class 2 forgings. The high-heat-input welding processes effecting reheat cracking, based upon tests of both laboratory samples and clad nozzle cutouts, include: strip clad, six-wire clad and manual inert gas (MIG) cladding processes. Testing also confirmed that reheat cracking did not occur with one-wire and two-wire submerged arc cladding processes. The cracks are often numerous and are located in the base metal region directly beneath the cladding. They are confined to a region approximately 0.125 inch deep and 0.4 inch long.
Cold cracking has occurred in ASME SA-508, Class 3 forgings after deposition of the second and third layers of cladding, where no pre-heating or post-heating was applied during the cladding procedure. The cold cracking was determined to be attributable to residual stresses near the yield strength in the weld metal and base metal interface after cladding deposition, combined with a crack-sensitive microstructure in the HAZ and high levels of diffusible hydrogen in the austenitic stainless steel or lnconel weld metals. The hydrogen diffused into the HAZ and caused cold (hydrogen-induced) cracking as the HAZ cooled, Destructive analyses have demonstrated that these cracks vary in depth from 0.007 inch to 0.295 inch and in l~ngth from 0.078 inch to 2.0 inches. Typical cold crack dimensions were 0.078 inch to 0.157 inch in depth, and 0.196 inch to 0.59 inch in . length. As with the reheat cracks, these cracks initiate at or near the clad/base metal fusion line and penetrate into the base metal.
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