Heavy water production: a success story for India
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Reduction in specific energy saved over Rs. 700 crore
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IF ONLY Dr. Homi Bhabha were alive today, he would have reasons to be immensely pleased. The heavy water production in India is now an enviable success story; the quantity produced is sufficient to meet the domestic demand. The Heavy Water Board (HWB) executed seven orders to export heavy water to South Korea and one to China. On February 25, this year, the Board supplied 4,400 kg of high quality, nuclear grade heavy water to M/S Spectra Gases Inc. USA.
"Government should explore the possibilities of using cheap hydroelectric power in India for manufacturing heavy water, on the one hand for our own requirements in a pile, and on the other for sale to other countries". Dr Bhabha, the nuclear visionary wrote to the then Prime Minister Jawaharlal Nehru on April 26, 1948. On March 15, the Heavy Water Day-2007, the HWB family met to review their achievements.
An ideal moderator
Heavy water, D{-2}O, is water in which both hydrogen atoms have been replaced with deuterium, the isotope of hydrogen containing one proton and one neutron.
It is an ideal moderator and not an absorber of neutrons.
A typical 220 MWe pressurised heavy water reactor needs about 275 tonnes of heavy water. Heavy water technology is complex as it involves concentrating and separating the heavy water or deuterium fraction by processing large quantities of an appropriate raw material.
First plant
In 1954, Dr Bhabha proposed the setting up of a heavy water plant at Nangal, based on electrolysis of water. The Nangal plant, the largest plant of its kind in the world, produced the first drop of heavy water on August 9, 1962.
The cost of electric power at Nangal, fixed by the Bhakra Board was 1.35 paisa per kilowatt-hr, revised later to 6 paisa per kilowatt-hr! Then Nangal heavy water became costly.
Next to water, hydrogen available from fertilizer plants is the best raw material to produce deuterium. Distillation of water or hydrogen or chemical exchange between hydrogen sulphide and water or ammonia and hydrogen are the processes adopted to produce heavy water.
HWB set up heavy water plants at Kota, Tuticorin, Thalcher, Hazira, Baroda, Thal, Hazira and Manuguru. The scientists and engineers of the HWB were continuously alive to technological breakthroughs and innovations in the field.
Heavy water industry is highly energy intensive. Through systematic efforts, HWB achieved 36 per cent reduction in specific energy (energy needed to produce a kg of heavy water) consumption over the last decade resulting in a cumulative saving of over Rs 700 crore.
Conservation measures help the captive power plant at Manuguru to sell at Rs 11 crore, the extra power of 12 MWe generated by it annually. The plant adopted notable echo-friendly uses of fly ash.
Miscellaneous activities
HWB is presently setting up a Technology Demonstration Plant at Rashtriya Chemicals and Fertilizers, Trombay to `pinch' traces of uranium from phosphoric acid to augment uranium resources (Rock phosphate contains 60-150 parts per million of uranium).
Deuterium-substituted polymers transmit light more efficiently. HWB entered into an MOU with a leading optical fibre manufacturer for the regular supply of 3 per cent dry deuterium gas at the rate of 15 cylinders per month for one year.
The Board developed processes to make many solvents used for fuel reprocessing, separation of fission products, waste management and the like and to enrich boron, needed in prototype fast breeder reactors as control rod material and for neutron detectors.
The Board patented a technology for flue gas conditioning to reduce suspended particulate emission from thermal power plants
No complacency
During 2005 and 2006, HWB received many awards, certificates and trophies.
K.S. PARTHASARATHY
Former Secretary, AERB
(ksparth@yahoo.co.uk)
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