 Currently there are 6 units under construction and 10 more units planned.The PHWR technology was introduced in India in the late 1960s with the construction of RAPS-1 CANDU reactor in Rajasthan.All the main components for first unit were supplied by Canada while India did the construction, installation and commissioning job.In 1974 after India conducted Smiling Buddha, its first nuclear weapons test Canada stopped their support of the project, delaying the commissioning of RAPS-2 until 1981.