Sale of uranium captured in battle (7)
I believe the answer is:
auction
'sale' is the definition.
(public sale)
'uranium captured in battle' is the wordplay.
'uranium' becomes 'U' (U is the chemical symbol for uranium).
'captured in' is an insertion indicator.
'battle' becomes 'action' (military action).
'u' placed within 'action' is 'AUCTION'.
'of' is the link.
(Other definitions for auction that I've seen before include "Selling" , "Public sale to highest bidders" , "Public sale at which bids are made" , "Public bidding sale" , "Where things are sold to the highest bidder" .)