Variational transition state theory calculations have been performed on the BW2 potential energy surface (PES) for abstraction and exchange reactions in the ClH2 system, and thermal rate constants and kinetic isotope effects are reported. Excellent agreement with two previous QM calculations on BW2 validates the present computational scheme. For abstraction reactions, general good agreement with various experimental measurements is obtained. For exchange reactions like D + ClH --> DCl + H, the results on BW2 are in better agreement with experiments than those on G3, as may originate from different topologies of these two PESs in the exchange barrier region. (C) 2004 Elsevier B.V. All rights reserved.