India's energy mix - the nuclear angle Read more on - Polity | Economy | Schemes | S&T | Environment The story: As fossil fue...
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India's energy mix - the nuclear angle
- The story: As fossil fuels slowly run out of favour, policymakers are focusing on renewable sources of energy. India was one of the early movers on nuclear energy, and today has 22 operating nuclear power reactors, with an installed capacity of 6780 MegaWatt electric (MWe). Among these are eighteen reactors of Pressurised Heavy Water Reactors (PHWRs) and type, and four of the Light Water Reactors (LWRs) type.
- The start: The first Prime Minister Pandit of India Pandit Jawaharlal Nehru was visionary enough to realise that India needed to be part of the latest scientific league, and gave push to the righ people with government funding. The nuclear energy programme in India was launched around the time of independence under the leadership of Dr. Homi J Bhabha.
- Three stage nuclear power programme of India: A three-stage nuclear power programme, based on a closed nuclear fuel cycle, was chalked out by scientists. The three stages are: (i) Natural uranium fuelled Pressurised Heavy Water Reactors (PHWRs), (ii) Fast Breeder Reactors (FBRs) utilising plutonium based fuel, and (iii) Advanced nuclear power systems for utilisation of thorium.
- For carrying out an efficient production of plutonium, the fissile material needed to fuel further growth in nuclear power capacity, a natural uranium fuelled heavy water moderated reactor is the best option. Thus India started the indigenous development of nuclear power plants based on uranium cycle in PHWRs, in the First Stage. India built twelve such reactors under operation, and then four more, and several others are planned. India become self sufficient in all aspects of the PHWR technology. The capacity factors of the operating PHWRs have been close to eighty percent during recent years, an excellent performance even with respect to international standards
- As a part of the Second Stage, India started the FBR programme with the Fast Breeder Test Reactor (FBTR), at IGCAR, Kalpakkam. This reactor, operating with indigenously developed mixed (U+Pu) carbide fuel, has already yielded a large volume of operating experience and a better understanding of the technologies involved. This has enabled India to design 500 MWe (prototype) FBR (Fig.2) that will utilise plutonium and the depleted uranium from the PHWRs.
- Quick update on technology:
- Prototype Fast Breeder Reactor (PFBR) is being implemented by the Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI), a wholly owned Enterprise of the Government of India under the administrative control of the Department of Atomic Energy (DAE).
- Pressurized Heavy Water Reactor is a nuclear power reactor, commonly using unenriched natural uranium as its fuel. It uses heavy water (Deuterium oxide D2O) as its coolant and moderator. The heavy water coolant is kept under pressure, allowing it to be heated to higher temperatures without boiling, much as in a typical pressurized water reactor. While heavy water is significantly more expensive than ordinary light water, it yields greatly enhanced neutron economy, allowing the reactor to operate without fuel enrichment facilities.
- Light Water Reactor is a type of thermal-neutron reactor that utilizes normal water as opposed to heavy water, and is fuelled by Low Enriched Uranium. It uses water as both a coolant method and a neutron moderator, and produces heat by controlled nuclear fission.
- Prototype Fast Breeder Reactor (FBR): A breeder reactor is a nuclear reactor that generates more fissile material than it consumes. These are designed to extend the nuclear fuel supply for electric power generation. Breeder reactors achieve this because their neutron economy is high enough to create more fissile fuel than they use, by irradiation of a fertile material, such as Uranium-238 or Thorium-232 that is loaded into the reactor along with fissile fuel. The PFBR is a 500 MWe fast breeder nuclear reactor presently being constructed at the Madras Atomic Power Station in Kalpakkam (Tamil Nadu), and fuelled by Mixed Oxide (MOX) Fuel.
- Mixed Oxide (MOX) Fuel - It is manufactured from plutonium recovered from used reactor fuel, mixed with depleted uranium, and provides almost 5% of the new nuclear fuel used today. It also provides a means of burning weapons-grade plutonium (from military sources) to produce electricity.
- Depleted Uranium - In order to produce fuel for certain types of nuclear reactors and nuclear weapons, uranium has to be "enriched" in the U-235 isotope, which is responsible for nuclear fission. During the enrichment process the fraction of U-235 is increased from its natural level (0.72% by mass) to between 2% and 94% by mass. The by-product uranium mixture (after the enriched uranium is removed) has reduced concentrations of U-235 and U-234. This by-product of the enrichment process is known as depleted uranium (DU).
- EXAM QUESTIONS: (1) Explain why India designed a three stage nuclear power programme. (2) What is the comparison of Uranium and Thorium? Explain. (3) What are the reasons India's nuclear installed capacity has lagged other renewable formats? Explain.
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