Madras Atomic Power Station (MAPS)

View All India Facilities

Last Updated: September 1, 2003
Other Name: N/A
Location: Near Chennai, Kalpakkan, Tamil Nadu, India
Subordinate To: Department of Atomic Energy (DAE)
Size: Two Pressurized Heavy Water Reactors, 170MWe each
Facility Status: Operational

The Madras Atomic Power Station (MAPS) is located within 30 kilometers of Chennai City and was the first indigenously built nuclear power station in India. The Department of Atomic Energy (DAE) and the Indian engineering firm Larsen and Toubro built the power station based on experience obtained by working with the CANDU reactors at Kota. The power station consists of two units. MAPS-1 was completed in 1981, but start-up was delayed due to a shortage of heavy water. After procuring the necessary heavy water, the Madras Unit-1 went critical in 1983 and began operating at full power in January 1984. MAPS-2 obtained criticality in 1985 and began full power operations in March 1986. The two Pressurized Heavy Water Reactors (PHWR) are capable of generating 170MWe each. This is under the original estimated capacity of 235MWe. The estimated capacities of the two reactors were lowered after the discovery of pieces of zircaloy in a moderator pump. These pieces were traced to substantial cracking in the reactor cooling system. The reactors' coolant tubes have also been plagued by cracks and vibration problems. On 26 March 1999, an accident at MAPS-2 resulted in the spillage of large amounts of radioactive heavy water. The accident resulted in seven technicians receiving heavy doses of radiation.

Since 1985, the unsafeguarded power station has supplied spent fuel to the Tarapur reprocessing plant. Spent fuel from the Madras Power Station provides India with another source of unsafeguarded plutonium for use in nuclear weapons or the fast breeder reactor program.

MAPS is also home to a pilot plant for the removal of tritium from heavy water that is used as a moderator in the reactors. As a result of fission and the irradiation of reactor components with neutrons in PHWRs, the deuterium atoms in the heavy water capture neutrons producing tritium. Utilizing the distillation facility available at the plant, Bhabha Atomic Research Center (BARC) scientists are able to remove the tritium produced. BARC scientists argue the detritium process is aimed at reducing the health hazards to reactor engineers caused by the presence of highly radioactive tritium. But the extraction of tritium raises proliferation concerns because of its use in the construction of fusion bombs and to boost the fission yields of thermonuclear weapons.

[1] Andrew Koch, "Selected Indian Nuclear Facilities," Center for Nonproliferation Studies (CNS), 1999,;
[2] DAE (Government of India), "Annual Report: 1997-1998"; DAE (Government of India), "Annual Report 1998-1999";
[3] David Albright and Mark Hibbs, "India's Silent Bomb," Bulletin of Atomic Scientists, Sept. 1992;
[4] Department of Atomic Energy (DAE),;
[5] Dr. A. Gopalakrishnan, "Nuclear Power: issues of nuclear safety." Frontline Online Edition, Vol.16, No. 06, 13-26 March 1999,;
[6] George Perkovich, India's Nuclear Bomb: the impact on Global Proliferation (Berkeley, CA: University of California Press, 1999), pp. 223, 235, 249, 284;
[7] Leonard Spector, The Undeclared Bomb (Cambridge, Massachusetts: Ballinger Publishing, 1988), pp. 84, 87, 92-93, 111;
[8] Leonard Spector and Jacqueline Smith, Nuclear Ambitions: The Spread of Nuclear Weapons 1989-1990 (Boulder, Colorado: Westview Press, 1990), pp. 67, 71, 83;
[9] Nuclear Power Corporation of India Limited (NPCIL),;
[10] T.S. Gopi Rethinaraj, "In the Comfort of Secrecy," Bulletin of Atomic Scientists, Vol. 55, No. 6, November-December 1999, pp. 52-57;
[11] "Tritium Breakthrough Brings India Closer to an H-Bomb Arsenal," Jane's Intelligence Review, January 1998;
[12] 2000 World Nuclear Industry Handbook (Wilmington, UK: Nuclear Engineering International, 2000), p. 118.

Country Profile
Flag of India

This article provides an overview of India’s historical and current policies relating to nuclear, chemical, biological and missile proliferation.

Learn More →

This material is produced independently for NTI by the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies at Monterey and does not necessarily reflect the opinions of and has not been independently verified by NTI or its directors, officers, employees, or agents. Copyright 2017.