  The intrinsic spins and their correlations are the least understood
characteristics of fission fragments from both theoretical and experimental
points of view. In many nuclear reactions the emerging fragments are typically
excited and acquire an intrinsic excitation energy and an intrinsic spin
depending on the type of the reactions and interaction mechanism. Both the
intrinsic excitation energies and the fragments intrinsic spins and parities
are controlled by the interaction mechanism and conservations laws, which lead
to their correlations and determines the character of their de-excitation
mechanism. We outline here a framework for the theoretical extraction of the
intrinsic spin distributions of the fragments and their correlations within the
fully microscopic real-time density functional theory formalism and illustrate
it on the example of induced fission of $^{236}$U and $^{240}$Pu, using two
nuclear energy density functionals. These fission fragment intrinsic spin
distributions display new qualitative features previously not discussed in
literature. Within this fully microscopic framework we extract for the first
time the intrinsic spin distributions of fission fragments of $^{236}$U and
$^{240}$Pu as well as the correlations of their intrinsic spins, which have
been debated in literature for more than six decades with no definite
conclusions so far.
