Inspect former atomic explosive device (7)
'inspect' is the definition.
'former atomic explosive device' is the wordplay.
'former' becomes 'ex'.
'atomic' becomes 'a' (eg in A-test, atomic test).
'explosive device' becomes 'mine' (mine is a kind of explosive device).
(Other definitions for examine that I've seen before include "Test, probe", "Investigate", "Check", "Appraise", "Question, test".)