Heavy water Programme in India

Heavy Water Board (HWB) Is an I&M unit under Department of Atomic Energy ard is responsible for meeting the
requirement of Heavy Water, an essential input for the Pressurised Heavy Water reactors (PHWR) which are presently the
mainstay ol the Nuclear Power Generation in India. HWB is responsible for process development, design, engineering construction and operation of Heavy Water Plants in India.

The Indian Heavy Water Programme is a success story of development of indigenous technology under the regime of stiff international technology control/sanctions. Today, India is not

only self sufficient in Heavy Water Production but also has the distinction of succesfully exporting Heavy Water to other countries for their nuclear power generation programme. India is perhaps the only country in the World who has mastered two technologies and exploited for industrial production of heavy water.

This was possible due to the Visionary zeal of eminent scientists and engineers like Dr. Homi Bhabha, Dr. Vikram Sarabhai and many others who have supported the programmes invloved in the development of technology virtually from concept to commissioning.

Technologies for production

The Indian Heavy Water production programme is based on the two technologies- H2S-H20 bithermal and N43-H2 monothermal chemical exchange processes. There are six plants operating in India on these two technologies.

While plants at Kota in Rajasthan & Manuguru in Andhra Pradesh are based on the bithermal H2S-H20 process, the
plants at Tuticorin in Tamil Nadu, Thal in Maharashtra and Hazira & Baroda in Gujarat operate on the monothermal NH3-H2 process.

It was indeed a great challenge to the engineers of HWB for development of this technology and building large-scale

production plants. The small separation factors, high degree of enrichment and large quantities of heavy water required
for nuclear power programme make the plants techrologically complex requiring large capital investments, extensive
energy consumption and a highly skilled manpower. All the heavy water plants handle Large quantities of toxic end
explosive gases and the engineering of these plants also require high degree of sophistication both in terms of providing
engineered safety features with high reliability.

As mentioned earlier the heavy water

plants are like chemical process plants but with a key difference in its level of energy consumption.The production of heavy water consumes energy of approximately 40 GJ/Kg of heavy water or about 17000 Kg of high pressure steam or 5400 units of equivalent electrtcity per kilogram!. This type of energy consumption is several folds higher than the conventional chemical plant and energy alone accounts for more than 70% of the cost of production.

The development of this technology went through many challenges and set-backs typical of development of any high technology product and having mastered this technology from seventies till early nineties, there was a paradigm shift in the focus of production at "any cost to production with least cost". This new mandate needed tremendous efforts in the field of energy management and conservation. HWB embarked on this in the right earnestness through multi-pronged strategies. A focused thrust on energy saving measures was initiated with an energy conservation policy drafted by CEO of HWB. The energy conservation campaign was carried out at different levels. Extensive energy audits were carried out in the plants and wherever possible the wasteful expenditure of energy was plugged. Plants were re-optimised for operating  at its best

efficiency points taking into consideration the local factors like cost of energy and other constraints. Various energy saving measures were incorporated including recovery of heat from waste streams, recycling of the effluent water, reoptimisation of the various hydraulic loops by impeller trimming or use of variable speed drives. The utility systems like the cooling water and the refrigeration cycle was re-optimised using innovative and integrated system design. All these efforts have yielded tremendous benefits. In the year 1999-2000, the specific energy consumption of all the plants on a weighted average basis stood at 38.23 GJ/kg, a whooping drop of 13.2% lower than the lowest achieved ever. The energy conservation campaign which began from 1995-96 onwards has saved almost to the tune of Rs 100 crore. The investment in terms of various plant modifications were really meager with a total expenditure of the order of about Rs 5 crore.

Heavy Water Board has accumulated vast experience in the field of energy conservation and energy management and is presently in a position to share its experience with the other chemical industry fraternity.

Besides this, HWB is presently developing a new process to delink the HWPs connected to the fertilizer industry by an ammonia water front end. Here again an energy driven process design has resulted in generating large quantity of refrigeration through an innovative ammonia absorption refrigeration system.

As a part of the diversification process, HWB has entered in the field of production of metal extractants like DEPHA. Alternate use of heavy water in medicinal applications also is under development. In the environmental front also HWB has developed a technology for reduction of the particulate matter emission in the flue gas at the Captive Power Plant at Manuguru. Implementation of the quality system also has been taken up by HWB in all the plants.

HWB has fully met the mandate given to it by Department of Atomic energy. With its vibrant, dynamic and wholesome activities, it is sure to scale much higher heights and meet any challenges given to it in the coming future.

CITATION

Heavy Water Board has made significant efforts which have resulted in substantial decrease in specific energy consumption per unit weight of heavy water produced. These efforts included development of simulation and modelling programmes for the entire process and optimization of the process parameters. Optimization has been carried out for all the peripheral equipments which include a large sized refrigeration system having different levels of refrigeration.

The energy consumption efforts have also been helped by the recycle of large amount of treated effluents, recovery of waste heat, analysis of heat recovery loops and performance monitoring of heat exchangers, modification of fans in cooling towers, etc. The entire process has been fine-tuned with the specific objective of reducing the specific energy consumption.

In recognition of these efforts, the Indian Chemical Manufacturers Association is happy to confer the I.C.M.A. AWARD FOR EXCELLENCE IN ENERGY CONSERVATION AND MANAGEMENT for the year 1999, on Heavy Water Board, Department of Atomic Energy, Government of India, Mumbai.