In expansion mode

The two Russian reactors at Kudankulam in Tamil Nadu's Tirunelveli district. - A. SHAIKMOHIDEEN

A confident NPCIL wants to build 36 imported reactors as India plans to generate 63,000 MWe by 2032.

WE have no choice but to pursue our nuclear power programme, said S.K Jain, Chairman and Managing Director, Nuclear Power Corporation of India Limited (NPCIL), in the context of the nuclear crisis in Japan. For, India does not have enough resources of fossil fuel such as coal or oil. It also does not have enough natural uranium deposits. He is confident that the crisis will not have any effect on the Indian programme. Nuclear power is so precious for the world that we cannot give it up, he said.

India has 20 nuclear power reactors, including two Boiling Water Reactors (BWRs) imported from the United States and 18 indigenously built Pressurised Heavy Water Reactors (PHWRs). Of these, the first unit (100 MWe) at Rajasthan, commissioned in 1973, has been shut down permanently and a decision is to be taken whether to rehabilitate it or decommission it. The 19 operating reactors have a total generating capacity of 4,680 MWe. The BWRs use enriched uranium as fuel and light water as both coolant and moderator, while the PHWRs use natural uranium as fuel and heavy water as both coolant and moderator.

The NPCIL has an ambitious programme to build at six locations 36 imported reactors that will have a total generating capacity of about 40,000 MWe. India plans to generate 63,000 MWe of nuclear power by 2032. The NPCIL has already built two Russian reactors (1,000 MWe each) at Kudankulam in Tirunelveli district, Tamil Nadu. The first unit is expected to go critical in April this year and the second six months later. Jaitapur in Maharashtra and Sonepur in Orissa will have French reactors, Kovvada in Andhra Pradesh and Chhayamithi Verdi in Gujarat will have American reactors and Haripur in West Bengal will get Russian reactors.

India is also building two indigenous PHWRs of 700 MWe each at Kakrapara in Gujarat and two of the same capacity have been launched at Rawatbhatta in Rajasthan. Four more PHWRs of the same capacity are planned, two each at Bargi in Madhya Pradesh and Kumharia in Haryana.

India is poised to construct a series of Fast Breeder Reactors (FBRs) that will use plutonium-uranium oxide as fuel and liquid sodium as coolant. The FBRs that will come up subsequently will use metallic fuel. The Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI) will build all the FBRs in India. The 500 MWe Prototype FBR (PFBR) under construction at Kalpakkam near Chennai is expected to go critical in 2012. Two more FBRs will come up at Kalpakkam. A Light Water Reactor of 700 MWe is also under development and it will use enriched uranium as fuel.

S.K. Jain is confident that we will be in a position to convince the people about the safety of Indian nuclear power plants. There is no cause for worry, be it about the indigenous nuclear power programme or the reactors to be imported, he said. He said a Japan-type situation would not arise in India. He pointed out that the east coast was 1,300 km away from the Sunda Arc (tectonic plate boundary) and the west coast was 900 km away from the Makaran fault. When a powerful earthquake struck Bhuj in Gujarat on January 26, 2001, the reactors at Kakrapara in Surat district continued to operate safely. During the 2004 tsunami, the two reactors at Kalpakkam shut down safely and were brought back on line in four days.

The mean sea level (MSL) at Kalpakkam is 6.096 metres and the high tide level is 6.705 m. The tsunami water level in 2004 was 10.496 m. The finished floor level of the nuclear island buildings of the PFBR site is 15.700 m, that is, they were 5.024 m clear of the tsunami water level in 2004. This means we have a high safety margin, said Prabhat Kumar, Project Director, PFBR.

At Kudankulam, too, tsunami protection has been factored in. We have a shore protection bund at an elevation of 7.5 metres above the MSL, said M. Kasinath Balaji, Site Director, Kudankulam Nuclear Power Project. The zero level (that is, the grade level) of all our buildings starts from 7.5 m above the MSL. We have a separate building called the safety building, which is flood-proof and has four diesel generator sets to provide alternative power supply [in case of a station blackout], he said.

The kind of decisions we have taken and the amount of money we have spent to safeguard our nuclear power plants is unparalleled, said Baldev Raj, Director, Indira Gandhi Centre for Atomic Research, Kalpakkam, which is the home of India's FBR programme.

What happened at Fakushima Daiichi was that while the six reactor buildings there withstood the jolt of the earthquake, it was the unprecedented flooding by the tsunami that knocked out power supply from the grid to the units, inundated the backup DG sets and ruined the battery power sets. Besides, no mobile electricity-generating systems were available. The sea water mixed with the storage [light] water in the units. The plant personnel could not decide whether to use the sea water to cool the reactor core. Before mobile power-generation sets could be arranged, the fuel rods heated up because pumps could not pump coolant water to cool the fuel rods. Hydrogen started forming when the zirconium sheaths around the fuel assemblies reacted with air and it combined explosively with oxygen.

S.K. Jain said: Yet, all the safety systems in those reactors worked. Even the shutdown systems, which are required to shut down the reactors in a few seconds, worked satisfactorily. All the safety systems worked as per design. The nuclear fission reactor in the units also stopped. So, as far as the design of the reactors at Fukushima Daiichi and their technology are concerned, there is nothing wrong.

He said the strength of the Indian reactors lay in their passive heat removal system. The PFBR and the Generation 3I + VVER-1000 imported reactors at Kudankulam and the other reactors to be imported will have a passive heat removal system. In the case of Kudankulam, it is located at 43 m above the elevation level. It works on the principle of natural convection, without needing any electricity. There is an additional storage tank of water inside the containment building in case a LOCA [Loss of Coolant Accident] occurs. In the most unlikely event of a core-melt, the Kudankulam reactors have a feature called the core-melt catcher, which is a huge tank of water into which the fuel will fall in case of a severe accident.

Hydrogen accumulation will not take place in the reactor building at Kudankulam. Hydrogen recombiners are provided so that hydrogen and oxygen will combine to form water. This precludes the possibility of accumulation of an explosive quantity of hydrogen in the containment.

I am convinced that there is no alternative to nuclear electricity in India both in the short term [about 10 to 15 years] and in the long term [40 to 50 years], S.K. Jain said. He denied that the electricity to be generated from the imported reactors to be built in India would be expensive. I will buy the reactors on my own terms, he asserted. The reactors should be technically acceptable to me and to our regulatory body, the Atomic Energy Regulatory Board. We will vet these reactors' designs to suit our requirements, he said. I cannot purchase expensive power. Otherwise, my company will become bankrupt.