Radio operator's set in ship (6)
I believe the answer is:
sparks
'radio operator's' is the definition.
(thesaurus)
'set in ship' is the wordplay.
'set' becomes 'park' (parking is a kind of setting**).
'in' is an insertion indicator.
'ship' becomes 'ss'.
'park' placed inside 'ss' is 'SPARKS'.
(Other definitions for sparks that I've seen before include "Electricians (informal)" , "Fiery particles for informal electrician" , "Electric discharges" , "Bright discharges" , "Radio officer" .)