The PAEC also played its part in the success and development of the uranium-enrichment programme by producing the uranium hexafluoride gas feedstock for enrichment. PAEC was also responsible for all the pre- and post-enrichment phases of the nuclear fuel cycle. By 1986 PAEC Chairman Munir Ahmad Khan had begun work on the 50 MW plutonium and tritium production reactor at Khushab, known as Khushab Reactor Complex, which became operational by 1998. After India succeeded with five underground nuclear tests (codename Pokharan-II) in Pokhran region in 1998, Pakistan, to the distaste of the international community, successfully carried out six underground nuclear tests in Ras Koh region of the Chagai Hills on May 28 (codename Chagai-I) and on Kharan region (codename Chagai-II) on May 30, proving Pakistan's nuclear capability. These tests were supervised and observed by physicist Samar Mubarakmand and other senior academic scientists from PAEC and the KRL.