ORNL-2106 - the Molten Salt Energy Technologies Web Site

ANP PROJECT PROGRESS REPORT
Fig. 3.4.31. Crack on Tension Side of Tube 2 of
NaK Inlet Header.
center line for metallographic examination. The
tensile side of tube 3, shown in Fig. 3.4.33,
illustrates typical severe cracking and corrosion
by the fuel mixture which circulated on the outside
of the tubes. A similar condition is evident in
Fig. 3.4.34, which is a panorama of the tension
side of tube 17. The opposite face of tube 17,
a panorama of which is shown in Fig. 3.4.35, does
not exhibit so serious a condition. It appears that
the corrosion and the stresses combined to form
an abnormally unfavorable condition.
196
Fig. 3.4.32. Bottom Side of NaK Outlet Header
Showing Distortion of Tubes.
The extent of the corrosion was investigated by
examining tube 93 to ensure that the large degree
of attack observed in the previous samples did
not result from the reaction of the two fluids at
the locations of the failures. The results of the
examination (Fig. 3.4.36) indicate that, in general,
severe corrosion was prevalent throughout the
tubes in the inlet header, The inner tube woll of
a typical tube is shown in Fig. 3.4.37; cracks
and corrosion emanating from the outer wall may
also be seen. A white deposit was found in the
cracks in some areas, as shown in Figs. 3.4.38
and 3.4.39. The nature of this deposit, (IS well
as a detailed investigation of the mass transfer
and corrosion, will be reported later.