In which phase does the nuclear membrane reappear during mitosis?

During mitosis, the nuclear membrane reappears in the telophase stage. This phase occurs after the chromosomes have separated and moved to opposite poles of the cell. At this point, the chromosomes begin to de-condense back into less tightly coiled chromatin. As the cytoplasm divides and two new nuclei form, the nuclear envelope reassembles around each set of separated sister chromatids, thus creating individual nuclei for each daughter cell.

This reformation marks the conclusion of nuclear division and is vital for ensuring that each new cell will have its own complete set of genetic material enclosed within a nuclear membrane. The reappearance of the nuclear membrane signifies that the cell is nearing the end of mitosis, preparing to enter the final stage of cell division.