|
During the 51 years of its formation, the Department of Atomic Energy (DAE) has taken impressive strides from fundamental scientific research to development and commercial applications of nuclear energy. The Department has mastered all the aspects of nuclear fuel cycle technology that ranges from exploration of nuclear minerals, mining and ore processing, fuel fabrication, power generation, reprocessing of spent fuel and nuclear waste management. It has also achieved high standards in safety and environment management. The nuclear technology developed in DAE’s research centres is being widely used in industry, health, agriculture, food preservation, urban waste management and desalination.
The Department has been pursuing a 3-stage Nuclear Power Programme that is focused on utilization of uranium and abundantly available thorium resources of the country for power generation. The programme comprises setting up of Pressurised Heavy Water Reactors (PHWRs) and associated fuel cycle facilities; Fast Breeder Reactors (FBRs) backed by reprocessing plants and plutonium-based fuel fabrication plants, and thorium based reactors.
On March 6 this year, DAE reached a momentous milestone when efforts of its organizations, mainly the Nuclear Power Corporation of India Ltd. (NPCIL) and Bhabha Atomic Research Centre (BARC), came to fruition with the successful attainment of criticality of a 540 MWe pressurised heavy water reactor at Tarapur.
Comprising twin-reactor units of PHWR type each of 540 MWe capacity, TAPP-3&4 has been built adjacent to Tarapur Atomic Power Station -1&2, on the shores of the Arabian Sea, in Thane district of Maharashtra. These reactors are based on natural uranium as fuel, and heavy water as moderator and coolant.
The first concrete (high strength Grade M-60 concrete developed indigenously), was poured on March 8, 2000 and it has taken less than 5 years for TAPP-4 unit to attain criticality. Earlier, on January 22, 2005, this unit had taken a major stride when all the systems of the reactor were integrated successfully, and after the clearance of the Project Design Safety Committee of AERB, its fuel loading had commenced.
The commissioning of TAPP-4 nuclear reactor, about eight months ahead of the schedule and achieving drastic reduction in the gestation period that compares well with international benchmark, has established technological and managerial prowess of NPCIL. An automatic computer controlled batching plant was established and concrete was pumped to the place of concreting. Permanent cranes and hoists were installed and commissioned well in advance, so that they could be made available for erection jobs inside the buildings. With the help of a heavy-duty crawler crane, the lowering of steam generator into position was completed in just three hours as against more than a month in earlier projects. The overall plant execution was done by contracting out mega-packages of activities rather than single activities. This approach simplified coordination, and increased speed of execution of various works. This technological and project management experience will be useful for future high-tech programme.
The design of TAPP-3&4 reactors incorporates all the basic features of the existing PHWRs. The safety features in the existing 220 MWe units, such as fast acting diverse independent shutdown systems, high pressure emergency core cooling systems, double containment, supplementary control room along with the safety objectives like redundancy diversity, avoidance of common cause failure, are incorporated in these units.
Since the 540 PHWR is a large reactor, some systems are much different from those used in the 220 MWe reactor of standardised design and a number of new systems are also needed in these large reactors. This necessitated research and development in several areas. Also, driven with the objective of maintaining and improving the indigenisation of nuclear power plant components, additional design innovations were carried out. Certain pieces of equipment were redesigned so that their manufacturing is within the capability of Indian industry. AERB has authorised synchronization and operation of the unit upto 90 per cent power level.
Maharashtra will receive 36 percent of electricity generated from TAPP-3&4, Gujarat’s share will be 19 percent and Madhya Pradesh’s 17 percent, and rest of the power will be supplied to Goa, Union Territories of Daman, Diu and Nagar Haveli, and to deficient states. The second reactor TAPP-3 of the project will be commissioned shortly.
NPCIL, that is responsible for the design, construction and operation of nuclear power reactors in India, now operates 15 reactors (2 boiling water reactors and 13 pressurised heavy water reactors). With the commissioning of TAPP-4 reactor, the total capacity stands at 3310 MWe. Five PHWRs and two light water reactors of NPCIL are under construction. After the completion of these reactors, the total installed nuclear power generation capacity will be 6730 MWe.
Successful commissioning of TAPP-4 has tremendously boosted the confidence of the Indian nuclear engineers and scientists. With this, India has entered the era of electricity generation from large size nuclear reactors. The achievement of high capacity factor and low gestation period of the Indian nuclear reactors have made them competitive with other types of electricity generating units. With a view to further bring down the per unit price of electricity, a larger reactor of 700 MWe capacity is being developed by NPCIL.
*Secretary, Department of Atomic Energy
|
