looking at the linearity of the shade, it seems there was some issue when that particular bead was being welded. Weld might not have been properly cleaned during the run or maybe improper 308 electrode. And also the weld joint breakage and that tint looks like two different issues.
Just my wild...
Seems like the drive key which was holding the shaft and bearing sleeve together got sheared off that led to movement and friction between both the components generating heat which cause the seizure and broken shaft.
timely inspection of weak components like keys and temperature protection...
@Artisi
Impeller was not found jammed.
Shaft entering in the bearing housing from DE side was found free in rotation in contrast with the remaining shaft going outside of housing. The shaft seems seized only in axial direction as we are unable to dismantle and remove it easily.
Lubricating Oil...
Tank Rim Seal Foam was found in the barrel of the vertical pump of around 1.5m x 1m dimension but i dont think such soft item can jam the impeller movement.
SHAFT IS BROKEN INSIDE DE BRG HOUSING AND IS NOT COMING OUT. DE BRG HSG RETAINER WAS FOUND RED HOT WHEN PUMP TRIPPED.https://files.engineering.com/getfile.aspx?folder=41b27546-f1c5-4eec-99af-6b9f2a8f4517&file=MDT_Booster_CS_Dwg_page-0001.jpg
