[ RadSafe ] DUF6 storage cylinder risk assessment

[James Salsman]

Where can I find the probabilistic risk assessments for the 
uranium hexafluoride storage tank maintenance and testing?

In particular, I'm trying to understand this statement:
"Storage cylinders must be regularly inspected for evidence 
of corrosion and leakage."  Does such inspection require 
unloading and reloading the tanks, and if so, what is the 
accident risk per event?

Thanks in advance.

Sincerely,
James Salsman