Prime Minister Narendra Modi on Monday visited a nuclear power plant here where a key procedure regarding power generation commenced.The commencement of 'core loading' of the country's indigenous Prototype Fast Breeder Reactor at Kalpakkam, located about 60 km from Chennai happened in the presence of the PM.This 500 MWe fast breeder reactor has been developed by Bharatiya Nabhikiya Vidyut Nigam Limited.The reactor core consists of control sub-assemblies, blanket sub-assemblies and fuel sub-assemblies.The core loading activity consists of loading of reactor control sub-assemblies, followed by the blanket sub-assemblies and the fuel sub-assemblies which will generate power.National Security Adviser Ajit Doval, among others, accompanied the PM.