Answer:

nuclear

Answer	Crossword Clue
NUCLEAR	Atomic
NUCLEAR	Core, as family
NUCLEAR	Like some subs

NUCLEAR	Kind of freeze
NUCLEAR	Kind of medicine
NUCLEAR	Of fission or fusion
NUCLEAR	Part of NRC
NUCLEAR	Like some families
NUCLEAR	Like some power
NUCLEAR	Like some potentially hazardous plants
NUCLEAR	Harold Urey's type of physics.

NUCLEAR	... physics.
NUCLEAR	Designating a form of energy.
NUCLEAR	Designating a type of power.
NUCLEAR	Kind of fission
NUCLEAR	Word with family or winter
NUCLEAR	Kind of family
NUCLEAR	Kind of power plant
NUCLEAR	Kind of fusion or fission