Inventor of strange reactor (7)
I believe the answer is:
creator
'inventor' is the definition.
(I've seen this before)
'strange reactor' is the wordplay.
'strange' indicates anagramming the letters.
'reactor' with letters rearranged gives 'CREATOR'.
'of' is the link.
(Other definitions for creator that I've seen before include "Person who makes or invents things" , "The Almighty" , "Originator - God" , "Inventor" , "Maker" .)