Knowledge Nugget | India and Canada sign Uranium pact: What you must know about uranium

India and Canada have signed major deals in an attempt to strengthen bilateral ties (File photo: PTI).

Key Takeaways: 

The Indian government and Canada’s Cameco have signed a uranium supply agreement to support India’s nuclear ambitions and to work towards a clean, reliable base ⁠load power, Carney said.

Uranium

1. Uranium is a naturally occurring radioactive element, which has the atomic number of 92 and corresponds to the chemical symbol U in the periodic table.

2. It belongs to a special group of elements called “actinides” — elements that were discovered relatively late in history.

3. Uranium is “radioactive”, which means it decays over time and releases energy in the process. Its special properties make uranium the main source of fuel for nuclear reactors. 

4. Uranium is among the more common elements in the earth’s crust — about 500 times more common than gold. According to the official website of the International Atomic Energy Agency, although it seems a very rare element, small amounts of uranium are present everywhere — in rock, soil, water, and even our bodies. There are also large amounts of highly diluted uranium in the ocean — approximately four billion tonnes.

5. Notably, uranium comes in several variations that differ in mass and physical properties but share the same chemical properties. Those are called isotopes. There are three natural isotopes of uranium — uranium-234 (U-234), uranium-235 (U-235) and uranium-238 (U-238). 

(Infographic credit: A. Vargas/IAEA website)

Uranium enrichment

1. Uranium-235 is the most commonly used nuclear fuel, however, natural uranium typically contains only 0.72 per cent of U-235 and most reactors need a higher concentration of this isotope in their fuel. Therefore, the U-235 concentration is being artificially increased through a process called enrichment.

2. This is done by subjecting a U-235 nucleus to neutrons. The nucleus immediately absorbs an extra neutron and consequently becomes unstable — and immediately breaks apart into two lighter atoms, and a few extra neutrons. This process releases what is known as atomic energy.

3. The fission of a U-235 atom produces about 2 to 3 new neutrons on average. If these new neutrons are then absorbed by other U-235 atoms, it creates an exponentially growing chain reaction. The math is simple: with each ‘generation’ into the chain reaction, the number of atoms engaged can increase by 2 to 3 times.

4. Even though not all neutrons engage in the fission process, as long as each fission leads to more than one additional fission, the chain reaction grows exponentially and releases large amounts of energy.

5. Approximately 99.3% of naturally occurring uranium is of the isotope U-238, which is not fissionable. Naturally occurring uranium, therefore, cannot be used in a weapon, or for that matter, in nuclear power plants.

Schematic diagram of a fission chain reaction. A U-235 atom absorbs a neutron, and fissions into two new atoms (fission fragments), releasing three new neutrons and some binding energy. Even if only one of these new neutrons collides with a U-235 atom (as shown in this graphic), which then fissions and releases two neutrons and some binding energy, the chain reaction continues. (Wikimedia Common)

6. Thus, uranium ore is enriched in order to increase the concentration of U-235. Most nuclear power plants require an enrichment of 3-4% U-235 to sustain a chain reaction. Fission bombs on the other hand need closer to 90% enrichment.

7. This is done in specific enrichment facilities using some extremely complex equipment. Notably, the equipment needed to enrich fuel for nuclear power generations is the same as that needed to enrich it for a bomb — leading to one of the great challenges of enforcing nuclear non-proliferation.

BEYOND THE NUGGET:  Small modular ‌reactors (SMRs)

1. SMRs are essentially advanced small nuclear reactors that have a power capacity of 30MWe to 300 MWe (megawatt electrical) per unit. Conventional nuclear reactors, the kind which are currently installed in India and elsewhere, usually have capacities to produce 500 MW of electricity or more.

2. The relatively simpler and modular design of SMRs—enabling their components to be assembled in a factory instead of being constructed on-site—lowers costs and allows flexible deployment, making them a much more attractive proposition in recent years.

Post Read Question

Consider the following statements with regard to the Uranium-235:

1. It is an extremely rare isotope of the heavy metal uranium.

2. It is the most commonly used nuclear fuel.

Which of the statements given above is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

(Sources: India and Canada sign Uranium deal in bilateral ties reset, target $50bn trade by 2030, iaea.org,

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