India is one of the world's largest consumers of electricity, and the bulk of it is generated from coal.
The new reactors amount to more than the country's present installed capacity of nuclear power. But it is not clear when they will begin working.
India currently operates 22 nuclear plants, with a capacity of 6,780 megawatts.
"A total of 7,000 megawatts will be added. It will help produce clean energy," Power Minister Piyush Goyal told reporters.
The planned nuclear units will generate business worth $11bn (Â£8.48bn) and create more than 33,000 jobs, the government said.
The homegrown reactors will be built under the ambitious "Make in India" initiative, with the government saying it will boost India's nuclear manufacturing capability.
India will build 10 heavy water reactors to boost its nuclear power capacity, the government has announced.