A milestone at Kalpakkam

The second stage of India's nuclear power programme gets under way with the beginning of the construction of the Prototype Fast Breeder Reactor at Kalpakkam.

in Kalpakkam

"BREEDER technology is certainly one of the most advanced and difficult undertakings in nuclear power engineering. That India, relying almost exclusively on its own resources, is able to embark on a breeder programme, bears witness to its great accomplishments in science and the resourcefulness of its engineers." This is the impression of Hans Blix after his visit to the Reactor Research Centre at Kalpakkam, Tamil Nadu, in December 1982 as the Director-General of the International Atomic Energy Agency (IAEA). About 22 years later, on October 23, 2004, India took a big, bold step forward in its nuclear electricity programme when Prime Minister Manmohan Singh inaugurated the construction of the Prototype Fast Breeder Reactor (PFBR) at Kalpakkam, which will generate 500 MWe. The event marked the beginning of the second stage of India's nuclear power programme.

The top brass of the Department of Atomic Energy (DAE) was delighted when Manmohan Singh wrote after going around the Indira Gandhi Centre for Atomic Research (IGCAR) and other nuclear facilities at Kalpakkam: "We are living in a world where science and technology have become the major determinants of power and wealth of a nation. The Department of Atomic Energy has served our nation with great distinction. The development of fast breeder reactor technology and its commercialisation are great steps forward in our nation's quest for self-sustained development. My heartiest congratulations and best wishes to all those associated with the Department of Atomic Energy and its various allied organisations."

The Reactor Research Centre, set up in 1971at Kalpakkam exclusively for doing research and development of breeder reactors, was renamed after Indira Gandhi in December 1985. Breeder reactors are called so because they breed more fuel than they consume.

The PFBR construction also signals the start of the commercial phase of the country's FBR programme. The nuclear power countries, except Russia, have not persisted with the breeder reactors for several reasons. But India's stakes in the programme are high (see box). In view of this, the DAE has concluded that breeder reactors are the key to the country's energy security and independence.

The DAE has drawn a road map which envisions building a series of breeders by 2050. To start with, four more reactors (in addition to the PFBR), each with a capacity of 500 MWe, will be built to meet the target of 20,000 MWe of nuclear energy by 2020. The DAE's newest public sector undertaking called Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI) will build the PFBR and other breeder reactors. The PFBR will be built at a cost of Rs.3,492 crores and will be commissioned in 2010. It will use plutonium-uranium oxide as fuel, and liquid sodium as coolant. The design-life of the reactor is 40 years and it can be extended by another 20 years. BHAVINI will operate the PFBR as a commercial power plant and sell the power to State Electricity Boards. When the PFBR starts generating electricity in 2010, it will be sold at Rs.3.20 a unit to the States.

Anil Kakodkar, Chairman, Atomic Energy Commission and Secretary, DAE, described the start of the PFBR construction as "a historic occasion" because the breeders "have the potential to generate a few hundred thousand megawatts". BHAVINI was a joint enterprise for bringing together the IGCAR's scientific expertise and the Nuclear Power Corporation of India's (NPCIL) construction and managerial expertise, he said.

Baldev Raj, Director, IGCAR, summed up the importance of the FBR programme thus: "This PFBR technology will be the basis for generation of 5,00,000 MWe, which will provide energy security to the country. The 5,00,000 MWe will come through the fast breeder reactor route." The IGCAR would be shortly launching the design and development of 1,000 MWe breeder reactors and (other) advanced versions with improved breeding in order to build energy potential speedily, he said.

A series of "FBR parks", each with two to four FBRs, a reprocessing plant and a fuel fabrication plant, are proposed to be set up. At Kalpakkam also, a reprocessing plant and a fuel fabrication plant will be set up. Kalpakkam is labelled "a good site" which can accommodate two more breeders. The FBRs will use the reprocessed plutonium and depleted uranium from the country's PHWRs. Enough spent fuel was already available with the existing PHWRs, and three reprocessing plants were operational at Trombay, Tarapur and Kalpakkam.

S.K. Jain, Chairman and Managing Director of both the NPCIL and BHAVINI, pointed out that the country, during the first stage of its nuclear electricity programme, had built up a comprehensive capability in designing, developing, building, operating and maintaining PHWR. Besides, the DAE was engaged in a life-extension programme of these reactors. Twelve PHWRs are operational now and six are under construction. The programme has now entered the commercial domain of breeder reactors.

The PFBR construction is proceeding at a fast pace on a sprawling site adjacent to the two PHWRs of the Madras Atomic Power Station. The administrative building was ready more than a year ago. The site assembly building, 180 metres long and 23 metres tall, is also ready. It is in this building that the PFBR's huge components such as the steam generator, the transfer arm, that is, the fuel handling machine, the safety rod mechanism, the control rod mechanism, the turbine and so on will be assembled, and then erected in the PFBR buildings.

Work on excavating the sprawling raft (foundation), going down to a depth of 18 metres, has been completed. On this common foundation will come up eight important buildings that constitute the nuclear island. These buildings are to house the reactor, control room, and two steam generators and to store the fuel, and so on. The reactor building will be 73 metres tall from the foundation, and the buildings housing the steam generator will be 85 metres tall.

Prabhat Kumar, Project Director, PFBR, said its construction was "the most challenging project both in terms of the technology to be deployed and the time of its completion". The excavation of the raft and the construction activity so far had proceeded smoothly.

Fabrication of the gigantic PFBR components involves complex high technology, and the IGCAR faced many challenges in indigenously developing the technology. It has already completed the technology development for most of the PFBR components and placed orders with the Indian industries for manufacturing them. The IGCAR also developed robots and special types of steel in its quest for developing the technology for the components. For instance, the steam generator is a huge component that is 23 metres tall. It generates the steam that drives the turbine for the generation of power. The steam generator is made of grade-91 ferretic steel, a special type of steel developed by the IGCAR. The steam generator is the most important component in the entire plant. Robots have been developed to scan the steam generator tubes to ensure their integrity and long-term performance. The transfer arm, which will load the radioactive fuel in the reactor, is another virtual robot. It is 23.5 metres tall. The control drive mechanism is 12 metres tall. The IGCAR developed these components from scratch and simulated their working in reactor conditions.

The main (reactor) vessel is a mammoth contraption that weighs about 3,500 tonnes, of which radioactive liquid sodium will weigh 1,150 tonnes. The vessel is 13 metres tall and 13 metres in diameter. It is highly instrumented and studies are under way on convection current variations, thermal fatigue damage due to variation in sodium level and so on. At the Structural Mechanics Laboratory, a scale-model of the reactor vessel is undergoing tests on a "shake-table". When the table shakes, it simulates the conditions of an earthquake. In the event of an earthquake, the liquid sodium will slosh and create stresses on the vessel.

"All these studies have been done. The final manufacturing technology will be over by December 2004. So today, with respect to technology development, there is absolutely no doubt in our mind that we have not left out any technology that will stand in the way of our completing the PFBR on time," said Baldev Raj. According to him, the IGCAR and BHAVINI are committed to building the reactor at less cost and time. "All our efforts will be to demonstrate that this first-of-its-kind high technology project in India can be built totally indigenously at less cost and less time than envisaged in the first project report," he added.

A FORERUNNER to the PFBR is the Fast Breeder Test Reactor (FBTR) at Kalpakkam, which has been operational for the past 19 years. The FBTR has had a chequered history. After the IGCAR was set up in 1971, France and India signed an agreement whereby France would help India in building an experimental reactor, which can generate 40 MWt/13MWe. France was a leader in breeder technology at that time and it was enthusiastic too about helping India to build an experimental breeder reactor. A team of engineers from India was trained on the Rapsodie reactor in France. The French gave the Indians the design to build a small breeder reactor at Kalpakkam and the fuel to be used was enriched uranium.

Construction of the FBTR soon got under way. India conducted its peaceful nuclear explosion in May 1974, which angered France. It pulled out of the collaborative agreement on building the FBTR and France said it would not supply enriched uranium, to run the FBTR. India took it up as a challenge and developed a totally different kind of fuel: plutonim-uranium mixed carbide, which is indeed a unique fuel. From its criticality in October 1995 to this day, the FBTR has been running on this innovative carbide fuel, and it has behaved well.

Baldev Raj said: "In its 19 years of operation, the FBTR has had an absolutely excellent track record. It has surpassed benchmarks set by other countries with respect to sodium, fuel, performance and so on. It is true that we did have some problems. A sub-assembly was bent due to fuel handling. There was a small sodium leak. There was reactivity co-efficient anomalies. But our teams successfully resolved them."

The challenges faced by IGCAR in running the FBTR has stood it good stead in designing the PFBR and developing the technology to manufacture its components.