Yes, INTRUSION is a Scrabble word!

Letter values in Scrabble US: I 1, N 1, T 1, R 1, U 1, S 1, I 1, O 1, N 1.

Is it a valid word?

INTRUSION is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

any entry into an area not previously occupied
entrance by force or without permission or welcome
the forcing of molten rock into fissures or between strata of an earlier rock formation
rock produced by an intrusive process
entry to another's property without right or permission