Primary modules over commutative rings

The radical of a module over a commutative ring is the intersection of all prime submodules. It is proved that if R is a commutative domain which is either Noetherian or a UFD then R is one-dimensional if and only if every (finitely generated) primary R -module has prime radical, and this holds precisely when every (finitely generated) R -module satisfies the radical formula for primary submodules.