Accurate time-dependent wave packet calculations have been performed for the isotopic N(D-2) + D-2 reaction on the recent reported 1(2)A '' DMBE (double many body expansion) potential energy surface of the NH2 system. The total reaction probabilities for total angular momentum J up to 75 have been calculated to get the converged integral cross-section over a collision energy range of 0.0-1.0 eV. Then, the ground-state thermal rate constant has been derived from the integral cross-section and the intermolecular isotope effect is further discussed. (C) 2007 Published by Elsevier B.V.