Cool Down Testing
is Cool Down Testing?
Cool Down Testing is an
alternative to on-line Acoustic Emission (AE) testing for hot reactors,
towers, columns and associated hot circuit piping systems. Cool down tests
always generate high loading in the longitudinal direction of a pipe or
vessel. This presents an ideal scenario for detecting hoop-oriented
defects. Loading in the hoop direction can be achieved if there is a
sufficient thermal gradient through the wall thickness of the vessel or
pipe. Thin-walled vessels cannot maintain a thermal gradient through the
wall thickness. They should not be considered as candidates for the Cool
Down test if longitudinally-oriented defects are suspected. In this case,
an on-line overpressure test is recommended.
Maximized Cool Down
A 10% over pressurization or
MONPAC test can also be conducted just before the Cool Down test is
performed. Different types of flaws that would be inactive during a Cool
Down now become evident. The over pressurization is done while the hot
vessel is on-line.