India’s civilian nuclear energy programme has stepped into the 75th year of its existence in 2021, a journey that began with the setting up of an Atomic Research Committee in 1946 under the chairmanship of Homi Bhabha, although the nation gained freedom from British rule only a year later, in 1947, while the country’s Atomic Energy Commission (AEC) was formed in 1948.
India’s first research reactor Apsara went critical in 1956, an event that marked the first milestone in Indian strategic science, leading, till date, to the construction of 22 operating nuclear power reactors in the country with a total capacity of nearly 6,800 MW. At a discussion held earlier this month at the Bangalore International Centre, M. R. Srinivasan, the Founder Chairman of the state-run operator Nuclear Power Corporation of India Ltd (NPCIL), and also a past Chairman of the AEC, traced the remarkable journey of India’s nuclear power programme, along with its international dimensions.
Describing the thinking among nuclear policy makers in the 1950s on selecting the type of reactors for power production, Srinivasan said that this consideration was dictated initially by the kind of fuel resources available in the country in the form of some, but not large, amounts of low- grade uranium. “Most of the reactors being built (overseas) then were using enriched uranium – U-238 and U-235 – which is the fissile component”, he said.
“Another possibility was to use natural uranium which didn’t require the enrichment process, because we lacked enrichment facilities. Our initial intention was to go for natural uranium-fuelled reactors in line with those being developed in Britain and France”, Srinivasan said. “These initial reactors would be followed in the next stage by fast reactors which would use the plutonium (Pu) by-product of the first-generation reactors, and that these would eventually produce more fuel out of thorium. That initial line of thinking is still a long-term objective of our programme to use thorium as an energy base”, he added.
India’s three-stage nuclear power production program had been conceived with the ultimate objective of utilising the country’s vast reserves of thorium-232. India has the world’s third largest reserves of thorium. The first stage envisages the use of pressurised heavy water reactors (PHWRs) to produce energy from natural uranium. Besides energy, PHWRs also produce fissile plutonium (Pu-239). The second stage involves using the indigenous fast breeder reactor (FBR) technology fuelled by Pu-239 to produce energy, as well as more Pu-239. By the end of the second stage of the cycle, the reactor would have produced, or “bred” more fissile material than it would have consumed.
While India has successfully completed the first stage of its nuclear programme, the second stage is taking much longer than expected, causing significant time delay and cost overruns. The FBR being developed in Kalpakkam in Tamil Nadu will use a mixed oxide of Pu-239 – derived from reprocessed spent fuel from the thermal PHWRs – and uranium-238 as fuel to generate energy. This nuclear reaction will also produce more Pu-239 by converting both U-238 in the fuel mix, as well as a blanket of depleted uranium surrounding the core, into plutonium. This plutonium will then be processed and used as nuclear fuel in a chain of commercial FBRs in the second stage of the nuclear programme.
The final stage of the cycle would involve the use of Pu-239 recovered from the second stage, in combination with thorium-232, to produce energy and uranium (U)-233 using “thermal breeders”. This production of U-233 from thorium-232 would complete the cycle, while the U-233 would then be used as fuel for the remaining part of the fuel cycle.
Srinivasan said that for the construction of the first reactors in the country in the sixties, the government adopted the mechanism of floating international tenders and received offers for both enriched and natural uranium reactors. “We found that the enriched ones were much more economical to build and operate as compared to the offers from UK and France. So we opted for Light Water Reactors (LWRs) of the type that was built in Tarapur (near Mumbai) at that time (commissioned 1969)”, Srinivasan said.
Noting that a large number of reactors used currently for power production worldwide are LWRs, he said that many experimental projects are also working on fast breeder reactors with the aim of utilising fuel resources more efficiently. “Reactors create a lot of fissile content in the spent fuel, and by recycling these we get a lot more energy output than is available in natural uranium or thorium”, he said.
Following the initial phase of international cooperation, India pushed for achieving greater self-reliance in the nuclear field and development of indigenous technology owing to strategic compulsions, Srinivasan said. , After two collaborative projects, first with the US at Tarapur and then with Canada at Rajasthan, we decided to go ahead on our own”, he said. “Nuclear is a high investment industry, and early on we realised that if we have to create a nuclear energy programme it has to be highly self-reliant, or otherwise you are vulnerable”, he added.
Srinivasan pointed out how India conducting an underground nuclear test in 1974 provoked an international embargo on the country’s nuclear trade, which, however, “helped the nation develop its independent capabilities” in the sector. “In the Madras Atomic Power Station (MAPS) at Kalpakkam (Tamil Nadu), where work started in the early seventies and the first unit went on stream in 1983, everything was built by India”, he said. The MAPS is India’s first fully indigenously constructed nuclear power station, with two units each generating 220 MW of electricity. The complex also houses the indigenously built prototype FBR – Bhavini – under construction, which will add 500 MW of electrical power to the national grid, and is likely to be operationalised in October 2022.
“By the early 1980s, we were able to design and build our own reactors and had achieved a high degree of self-reliance. We subsequently designed and built PHWRs at other locations, scaling up from 230 MW to 500 MW and now up to 700 MW, the first one of which has been made functional in Kakrapar (Unit 3)”, Srinivasan added.
In July 2020, India achieved criticality with its first indigenously built 700 MW PHWR for the Kakrapar unit 3 in Gujarat state. Three other PHWRs are already under construction – Kakrapar unit 4, and Rajasthan units 7 and 8 in Rajasthan. Eight reactors are under construction with a combined capacity of 6,200 MW. On completion of these under construction, NPCIL’s capacity will reach 12,980 MW by 2025.
In addition, the government has given administrative approval and financial sanction for 12 new reactors with a total capacity of 9,000 MW. India’s current nuclear power capacity is expected to increase to 22,480 MW by 2031 on the completion of these proposed projects. The 10 PHWRS approved for construction in the fleet mode are units 5 and 6 at the Kaiga in Karnataka state, units 1 and 2 at Chutka in Madhya Pradesh, 4 units at Mahi Banswara in Rajasthan and units 1 and 2 at Gorakhpur in Haryana.
Currently two Russian-made VVER units of 1,000 MW capacity each are operating at the Kudankulam NPP (KNPP) in Tamil Nadu. Russian state atomic energy corporation Rosatom are the equipment suppliers and technical consultants for KNPP, where 4 more VVER-1000 units are under construction. As per an intergovernmental agreement, Rosatom will also help construct 6 more units in India at another location.
The former AEC Chairman admitted, however, that the drive to self-reliance in nuclear technology has come at the cost of slower than expected delivery and underperformance. “India’s desire to achieve localisation has been a time-consuming process. Besides, India also has to balance its investments in nuclear power with other kinds of investment that are capital intensive”, he said.
The signing of the Indo-US civilian nuclear agreement in 2008 signalled the South Asian nation’s return to global nuclear trade, and Srinivasan cited India’s participation in the world’s largest nuclear fusion reactor project – ITER (International Thermonuclear Experimental Reactor) – as a prime example of the indigenous capability acquired in atomic energy production.
The ITER machine, being assembled in Cadarache, France, to replicate the fusion power of the sun in order to enable generation of clean unlimited energy, is intended to demonstrate that fusion power can be generated on a commercial scale. The ITER project’s 35 member countries include China, India, Japan, Korea, Russia, UK, US and the European Union. Millions of components from all over the world will be used to assemble the giant reactor, which will weigh 23,000 tonnes.
“India is a partner in the multi-nation ITER project and is supplying crucial components for the fusion reactor. We are supplying the cryogenic tank, or the cryostat cold chamber, which has been fabricated in India by a leading engineering company”, Srinivasan said. Among the components is the 30-metre-diameter cryostat manufactured by India, which surrounds the reactor and keeps it at the extremely low temperature required.