The fourth unit of the Kakrapar Atomic Power Project (KAPP-4) in Gujarat, with 700 MWe capacity, started controlled fission chain reaction and thus became critical at 1.17 am on December 17. Kakrapar is situated about 80 km from Surat.
The 700 MWe units are the largest indigenous nuclear power reactors to be built by the Nuclear Power Corporation of India Limited (NPCIL), a public sector undertaking of the Department of Atomic Energy.
The 700-MWe unit-3 of KAPP started generating commercial electricity from August 30.