Distribution Of Nuclear Minerals
- Uranium (U) is a radioactive element that averages one to four parts per million in the Earth's crust.
- Natural uranium contains about 0.7% of the U-235isotope (the fissile isotope) and 99.2% of the U-238
- Commercial deposits of uranium may include concentrations of uranium minerals such as carnotite, brannerite and uraninite.
- Major uses for uranium are as a fuel for nuclear power reactors for electricity generation, in the manufacture of radioisotopes for medical applications and in nuclear science research.
Distribution of Uranium in the world
The occurrence of Uranium can be observed in a number of different geological environments. E.g. most Canadian resources are unconformity-related while Kazakh uranium resources are mostly sedimentary. Additionally, a large reserve of uranium is estimated to be in sea water. Uranium ore is mined in several ways: by open pit, underground, in-situ leaching, and borehole mining.
Mines in Canada, Australia and Kazakhstan cover over two-thirds of the uranium production across the world. As per 2016 data, Kazakhstan is the largest producer of uranium with 39% of world supply, followed by Canada (22%) and Australia (10%).
Australia: Australia possesses around 30% of the world's known recoverable uranium reserves. While Australia has the largest reserves opposition to uranium mining has been substantial in Australia. Australia's identified uranium resources occur in the Northern Territory and all states except Victoria and Tasmania. Olympic Dam in South Australia is the world's largest uranium deposit.
Kazakhstan: Kazakhstan contains about 13% of the world's recoverable uranium. Tortkuduk & Myunkum, Inkai, Kharasan etc. are the major uranium mines in Kazakhstan.
Canada: Canada was the world's largest uranium producer for many years, but in 2009 was overtaken by Kazakhstan. The McArthur River Mine and Cigar Lake Mine are major uranium producing mines in Canada. The McArthur River Mine in Canada is said to be the most productive uranium-producing mine in the world.
Other important countries with large known uranium reserves include Russia, South Africa, Niger and Namibia etc.
Uranium deposits of India
There are no significant deposits of uranium in India, and most of India s uranium need is met through imports. However, the growth of uranium industry has shown an extraordinary up-trend during last one decade.
In India, Uranium deposits occur in the Dharwar rocks. Geographically, uranium ores are known to occur in several locations along the Singbhum Copper belt (Jharkhand). It is also found in Udaipur, Alwar and Jhunjhunu districts of Rajasthan, Durg district of Chhattisgarh, Bhandara district of Maharashtra and Kullu district of Himachal Pradesh.
The first ever uranium deposit to be discovered in India was Jaduguda in Singhbhum Thrust Belt (Jharkhand). It was discovered in 1951. This discovery of uranium at Jaduguda in this belt paved the way for intensive exploration work, and soon a few more deposits were brought to light in this area. Some of these deposits like Narwapahar, Turamdih and Bhatin are well-known uranium mines of India.
New uranium mines in other states include - Lambapur-Peddagattu mine in Andhra Pradesh and Domiasiat mine in Meghalaya which are expected to boost uranium production in India.
- Natural thorium is usually almost pure 232Th, which is the longest-lived and most stable isotope of thorium
- Thorium is more abundant in nature than uranium.
- Thorium only occurs as a minor constituent of most minerals and was for this reason previously thought to be rare.
- Monazite The most important commercial source of thorium is Monazite which is mainly the phosphates of various rare-earth elements. It occurs in large deposits worldwide, principally in India, Brazil, Malaysia, South Africa and Australia.
- It contains around 2.5% thorium on average, although some deposits may contain up to 20%
- It is a fertile and not a fissile material. It can only be used as a fuel in combination with a fissile material such as recycled plutonium.
- Thorium fuels can breed fissile uranium-233
- This uranium-233 can further be used in various kinds of nuclear reactors.
- Recent indications are that in the near future, thorium would emerge as a fission fuel of greater potential than thorium.
Distribution of Thorium in the world
Monazite is the chief source of thorium in the world. Though it is a constituent of some pegmatites and granites, such sources are not commercially viable. Commercially viable deposits of Monazite can be found mainly in the beach sands in the coastal tracts of India, Brazil, Australia, Ceylon and Malaysia.
Thorium deposits in India
India has the largest deposits of monazite in the world. The richest monazite deposits in the world occur in Kollam and Palakkad districts of Kerala, Mahanadi river delta in Odisha and near Vishakhapatnam in Andhra Pradesh.
Monazite concentrations are not as good on the eastern coast as on the western and southwestern coasts. However, small deposits are found along the Tanjore and Vishakhapatnam coasts.
Kerala and Tamilnadu: Thorium is mainly obtained from monazite and ilmenite in the beach sands along the coast of Kerala and Tamil Nadu.
Odisha: monazite is found in the coastal tracts of Cuttack and Ganjam districts of Odisha where the thickness of the placer is about 30 cm with a monazite content of 2.5 per cent. Minor occurrences have been noticed between Chicacole River and Chilka Lake also.
Andhra Pradesh: In Andhra Pradesh thick ilmenite and monazite placers are found around Vishakhapatnam and Bhimunipatnam.
Nuclear Power Plants in India
The important nuclear power projects are Rawatbhata near Kota (Rajasthan), Narora (Uttar Pradesh), Kaiga (Karnataka), Tarapur (Maharashtra), Kalpakkam and Kudankulam (Tamil Nadu) and Kakarapara (Gujarat) etc.
India s three-stage nuclear programme
In 1954 Homi Jahangir Bhabha envisioned India s nuclear power program in 3 Stages to suit the country s resource profile
First stageHeavy Water Reactors - with Natural uranium as fuel with Plutonium as a byproduct
Second StageFast Breeder Reactors initially fueled by Mix of Plutonium from the first stage and natural Uranium. The Uranium will produce more Plutonium. Once sufficient stocks of Plutonium are built, Thorium will be introduced to convert it into U-233 for the third stage. A 500 MW Prototype Fast Breeder Reactor at Kalapakkam is set to achieve criticality.
Third StageThorium based reactors - a mix of thorium and uranium from 2nd stage fuels the reactors. The thorium transmutes to U-233 as in the 2nd stage, which powers the reactor. Fresh thorium can replace the depleted thorium in the reactor core, making it essentially a thorium-fuelled reactor even though it is the U-233 that is undergoing fission to produce electricity.
Advantages of Thorium Based reactor
- We have one-third of global Thorium reserves while only 1-2 % Uranium reserves mainly found in Monazite sand deposits of Kerala
- So it will reduce our dependence on Uranium imports so reduce import bills
- It will also provide sustainability to our nuclear energy program as imports can be restricted in the warlike situations
- Thorium based reactors are cheaper due to higher burn-up
- It will produce far less waste than present-day reactors so reduce the problem of waste disposal
- Miniscule waste generated that is toxic will last only for 300-400 years due to less radioactive life
- More proliferation resistant than current reactors - This is because the U-233 produced by transmuting thorium also contains U-232, a strong source of gamma radiation that makes it difficult to work with.
- Due to these advantages, other countries have also shown interest in Thorium based reactors India can take advantage of being an early starter
What is stopping us?
- As per scientists in BARC, we have all the technologies in place
- A critical shortage of fissile material is the biggest impediment
- India will have to develop many more FBR and they will have to work for decades before we can build sufficient stockpile
- An obvious solution is procuring fissile material from the international market
- No law explicitly forbids Plutonium NPT merely mandates safeguards for plutonium trade
- The US could emerge the greatest obstacle to Plutonium commerce it is against reprocessing but cannot forbid Plutonium trade
- If India procures plutonium, it will reduce the burden of countries like the UK, Japan etc. who have the considerable burden of Plutonium stockpile