Uranium, that strategic metal
India's ambitious nuclear program is based on the availability of sufficient uranium. But, do we have enough uranium resources in our country to meet the increasing demand? M S S Murthy thinks not.
The key to the success of a country's nuclear program is the availability of uranium. At present, the share of nuclear power in the country is only about three per cent of the total electricity generation. This is contributed by 17 power plants with a gross capacity of 4120 megawatt-electrical (MWe). Answering a question in the Loka Sabha on March 14, 2007 the government replied that it plans to progressively increase the nuclear power generation to 7280 MWe by completing the seven projects under construction by the end of 11th plan (2007-2012). In the 11th plan it is proposed to start work on another 7600 MWe capacity, reaching a total generation capacity of 15,000 MWe by the year 2020 through indigenous efforts. All this capacity build-up will be based on indigenously designed natural uranium and pressurised heavy water moderated reactors.
Do we have enough uranium to achieve this capacity?
Exploration
Uranium occurs in nature in the form of minerals like uraninite, pitchblende and coffinite. These are found in various types of rock formations in the earth crust. The ore grade concentration of uranium in the rocks ranges from 250 to 1700 ppm in India.
Uranium is mildly radioactive. It decays with a long chain of radioactive elements to stable lead. Some of them emit powerful gamma photons which can be easily detected during exploration.
The Atomic Minerals Directorate for Exploration and research (AMD), set up under the Department of Atomic Energy (DAE), is entrusted with the task of uranium exploration in the country. Various strategies such as satellite pictures and aerial survey are employed to delineate geological formations which can harbor uranium bearing minerals. Airborne reconnaissance survey with sensitive gamma ray detectors further narrow down the target areas. Then radiometric survey with hand-held gamma ray detectors and geological survey localise the possible deposits. Samples taken from both surface and at various depths from such areas are analysed in the laboratory for confirming the presence of uranium and its concentration. These parameters help in deciding whether it will be economical to mine uranium from the site.
The first uranium mine was commissioned in 1967 at Jaduguda in the present Jharkhand state. Since then three more mines have been established, one each in Narwapahar (1995), Turamdih (2002) and Bagjata (2007), all in Jharkhand. Some of the other deposits that have been identified in Jharkand are located in Mohuldih, Nandup, Rajgaon and Garadih.
AMD has discovered sizeable deposits in other states also: for example, Bodal and Jajawal in Madhya Pradesh; Domiasiat (known to be one of the largest and the richest), Wahkyn and Tyrani in Meghalaya; Lambapur-Peddagatta and Tummalapalle in Andhra Pradesh; Bastar district in Chhattisgarh and so on. These are in various stages of development and mining is expected to begin at some of these sites by 2010.
Favourable uranium mineralisation has also been identified at Gogi in Karnataka, Gandi in Andhra Pradesh, Rohil in Rajasthan and Durg district in Chhattisgarh.
From Ore to Reactor
The mined ore is processed at uranium mills at Jaduguda, Batin and Narwapahar, where it is converted into uranium oxide - popularly known as 'Yellow cake'. It is then sent to the Nuclear Fuel Complex at Hyderabad for fabrication into fuel for the country's pressurised heavy water reactors (PHWR).
Total uranium from currently known deposits is estimated to be equivalent of 94,000 tons of yellow cake. It is estimated that it can support a nuclear power program of 10,000 MWe for a period of 40 years.
But all is not well on the uranium front. The Nuclear Power Corporation of India Limited (NPCIL), under the DAE, has acknowledged that the industry is facing a severe mismatch between the demand and supply of uranium.
A reactor of 220 MWe (which is the installed capacity of most operating reactors in the country) has to be initially loaded with about 61 tons of U3O8 as fuel. To maintain efficient performance, about 33 tons of fuel has to be replaced every year. Hence, to keep the reactors producing electricity at the maximum capacity factor, more than 700 tons of uranium oxide is required per year. However, the amount of uranium produced in 2006 was only about 260 tons. Hence, about 12 of the 17 plants which produced about 15.6 billion kilowatt-hours of electricity in 2006 have been working only at 50 to 70 per cent capacity factor against a capacity factor of 90 per cent.
Why so? According to the DAE, three positive developments have contributed to this mismatch. First, it is the rapid increase in the nuclear power program in the recent years. Secondly, with improvements in technology, the power plant capacity has steadily grown. Each reactor can now burn more uranium and produce more energy. Thirdly, the gestation period, that is - the time between the civil work and commissioning of the reactor - has been reduced from 10-12 years to 4-5 years. This has reduced the lead period for planning.
Unfortunately, there is also a negative side to the story. Though new deposits are being discovered, environmentalists, citizens' groups, NGOs and even political parties are raising objections to mining and processing activities. Pollution of water resources from uranium tailings, radiation hazards to people living in the vicinity, displacement of tribals, inadequate compensation for the land acquired, encroachment to reserve forest areas, etc. have all been cited as reasons. These problems have been affecting not only new sites but also working mines. The NPCIL has cautioned that delay in commissioning new mines and mills could lead to further fuel shortage and jeopardise the nuclear power program.
One may argue that the country has abundant resources of thorium which can be converted into fissile material in breeder reactors. However, nuclear scientists feel that the prerequisite for the thorium utilisation program is the setting up of at least 10,000 MWe capacity (PHWR).
The government is ambitious of increasing the nuclear power capacity to 50,000 MWe by 2032. The present technology of natural uranium fuel in pressurised heavy water reactors, on which most of the current Indian program is based, is not best suited for this quantum jump.
Light water reactors with enriched Uranium-235 (to about three per cent) is the technology employed the world over. It may also help an earlier induction of the thorium cycle. However, India does not have enough expertise in light water technology.
Faced with this triple constraint of limited uranium deposits, opposition to uranium mining, and an urgent need for jacking up energy production, the government is seeking international cooperation in the supply of both fuel and technology.
The civil nuclear agreement between India and USA has to be viewed in this context.
http://www.deccanherald.com/Content/Feb122008/snt2008021151705.asp
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