The evolution of dislocation clusters in High Performance Multicrystalline Silicon was studied by means of photoluminescence imaging, defect etching and Electron Backscatter Diffraction. Cluster height was found to increase as function of lateral size. The largest clusters were found to exist in twinned grains or spanning multiple grains. Dislocation clusters were seen to originate at CSL boundaries and terminate at random angle grain boundaries. It is suggested that termination, as well as generation of dislocation clusters are growth phenomena, which are controlled by the dislocations following the growth front, and that the successful termination of dislocation clusters is a simple function of distance between grain boundaries able to terminate the dislocations at the growth front. It is also suggested that crystal orientation may influence the mechanism through the ability of dislocation clusters to traverse the grain laterally from a generation to a termination site.