  An asymptotic analysis is used to derive a set of diffusion approximations to
the nonclassical transport equation with isotropic scattering. These
approximations are shown to reduce to the simplified P$_N$ equations under the
assumption of classical transport, and therefore are labeled nonclassical
SP$_N$ equations. In addition, the nonclassical SP$_N$ equations can be
manipulated into a classical form with modified parameters, which can be
implemented in existing SP$_N$ codes. Numerical results are presented for an
one-dimensional random periodic system, validating the theoretical predictions.
