Respected Sh. Kalyani ji,
We all agree that CENVAT is admissible, only contention is eligibility as an "Input" or "Capital Goods".
Have taken into account the aspect of manufacture of Storage Tank while sharing the opinion. Until and unless storage Tank comes into existence, Plates can't be treated as parts of Capital Goods. Plates are used for manufacture of storage Tank in the present case.
Explanation to Input definition prior to Notification No. 03/2011-NT dated 01.03.2011 includes Input used for the manufacture of Capital Goods. "Input" from 01.04.2011 means "All goods used within the factory of manufacturer" (does not correlate Input to FG only).
CENVAT is allowed by department as an Input / CG considering the facts which might differ case to case basis.
Thanks for revert as each query enriches the thought process.