Russian-designed AES-92 VVER-1000 reactors. Construction began 29 June 2017. Physical progress 80.51 percent as of March 2026. Unit 3 expected commissioning in 2026. In April 2026, NPCIL achieved spill to open reactor stage for Unit 3. Unit 4 reactor pressure vessel lifted into position January 2025. Part of 6-unit Kudankulam complex which will be Indias largest nuclear station at 6000 MW when complete. Schedule update (September 2026): Rosatom's CEO said on September 14, 2026 that Unit 3 is in the final stages of completion, with Russia having supplied 99% of its equipment, and that its physical startup (fuel loading and first criticality) is expected in spring 2027, and that commissioning operations for Unit 4 will begin by the end of 2027; an earlier government reply in the Rajya Sabha had given 2026 for unit 3 and 2027 for unit 4. The projected operational date is moved to the end of 2027.