Cluster dynamics (CD) is a fast method for simulating long-term defect evolution in materials under irradiation. However, CD models based on mean-field rate theory do not account for spatial correlations between defects/clusters in cascades. Object kinetic Monte Carlo (OKMC) models take intrinsically account of defect spatial correlations, but they are limited by time scale and irradiation dose. A CD model with spatial correlation effect, termed as CD-SC, is developed based on a simple constant-time annealing method to determine CD source term by coupling Monte Carlo (IM3D) and OKMC (MMonCa) models. It shows that, results by CD-SC match those by full OKMC well. It is helpful for accuracy improvement of sequential multi-scale models of long-term radiation damage under typical irradiation conditions.