The Heavy Water Plant at Manuguru, Andhra Pradesh is based on the Bithermal Hydrogen Sulphide-Water (H₂S-H₂0) Exchange Process. This plant with a capacity of 185 MTY is the second plant based on this process, the earlier one being at Kota, Rajasthan for which the complete technology has been developed indigenously by BARC and HWB.

The Manuguru site was chosen because of its proximity to Singareni coal fields and Godavari river which provide respectively large quantities of coal and water required by the plant. The nearest rail head Manuguru is at a distance of 10 KM from plant site.

The main heavy water plant consists of two streams and the process employed is the combination of two processes namely isotopic exchange reaction between H₂S and H₂0 followed by vacuum distillation. As H₂S gas is very toxic, corrosive and hazardous in nature, care has been taken in the design of the plant, selection of equipment and materials adhering to stringent fabrication procedures and codes to ensure the production of heavy water in a safe manner. The exchange process operates at about 20 atm. pressure and at a temperature of 30 to 130 deg.C. while the vacuum distillation plant works at a pressure of 100 mm Hg absolute. The isotopic exchange reaction which is the heart of the technology is carried out with the aid of specially designed efficient trays. The H₂S gas required for the process is manufactured in a separate unit at the plant premises by the chemical reaction between sodium sulphide and sulphuric acid.Very elaborate H₂S detection instrumentation is provided not only in the plant but also in the surrounding areas to meet the requirements of the off-site emergency plans.