The Dhruva reactor is India's largest nuclear research reactor. It was the first nuclear reactor in Asia proper. Located in the Mumbai suburb of Trombay at the Bhabha Atomic Research Centre (BARC), it is India's primary generator of weapons-grade plutonium-bearing spent fuel for its nuclear weapons program. Originally named the R-5, this open pool reactor first went critical on 8 August 1985 after 10 years of construction. However, the unit did not attain full power until 1988. The reactor experienced at least one serious accident when 4 metric tons of heavy water overflowed from the reactor core in 1985 following vibration problems.