Owned and operated by the DAE's Heavy Water Board (HWB), the Thal Heavy Water Plant is located in the Thal-Vaishet village in the Raigad district of Maharashtra. The plant uses the ammonia-hydrogen exchange process to produce up to 110Mt of heavy water per year. Unlike earlier HWB heavy water plants, the Thal facility is a second-generation plant that was reportedly built indigenously. Although home-built, the plant was a modification of M-S Gelpra's design and received engineering support from Denmark's Haldor Topsoe. Construction was completed in 1986 by India's Rashtriya Chemicals and Fertilizers (RCF) at an estimated cost of 1.9 billion rupees. An RCF fertilizer plant is integrated into the Thal facility to provide the facility with ammonia and steam. The heavy water plant began operations after being commissioned in February 1987.

Sources:
[1] Andrew Koch, "Selected Indian Nuclear Facilities," Center for Nonproliferation Studies, 1999, http://cns.miis.edu;
[2] Heavy Water Board (DAE-Government of India), www.heavywaterboard.org;
[3] Rashtriya Chemicals and Fertilizers (RCF), www.rcfltd.com.