Let R be a commutative ring with identity and R(RM) denotes the bounded lattice of radical submodules of an R-module M. We say that M is a radical distributive module, if R(RM) is a distributive lattice. It is shown that the class of radical distributive modules contains the classes of multiplication modules and finitely generated distributive modules properly. It is shown that if M is a semisimple R-module and for any radical submodule N of M with direct sum complement N~, the complementary operation on R(RM) is defined by N′:=N~+rad(0), then R(RM) with this unary operation forms a Boolean algebra. In particular, if M is a multiplication module over a semisimple ring R, then R(RM) is a Boolean algebra, which is also a homomorphic image of R(RR)