Uranium in barrel with wheat (5)
I believe the answer is:
durum
'wheat' is the definition.
(durum is a kind of wheat)
'uranium in barrel' is the wordplay.
'uranium' becomes 'U' (U is the chemical symbol for uranium).
'in' indicates putting letters inside.
'barrel' becomes 'drum' (synonyms).
'u' inserted within 'drum' is 'DURUM'.
'with' acts as a link.
(Other definitions for durum that I've seen before include "Wheat variety" , "It makes pasta" , "Kind of wheat used to make pasta" , "Kind of hard wheat" , "Wheat for pasta flour" .)