Comparing Energy Production: Nuclear Fission vs. Coal Burning

When we talk about producing large amounts of energy, especially for electricity generation, we look at different sources and processes. The options provided compare energy obtained from burning coal with energy obtained from nuclear fission of materials like uranium and thorium.

Let's understand the fundamental difference between burning coal and nuclear fission:

• Burning Coal: This is a chemical reaction. Chemical reactions involve the rearrangement of atoms and the breaking and forming of chemical bonds. The energy released comes from the difference in bond energies between the reactants and products. While burning a significant amount of coal produces substantial energy, the energy released per unit mass is relatively low compared to nuclear reactions.
• Nuclear Fission: This is a nuclear reaction. Nuclear reactions involve changes within the nucleus of an atom. Fission is the process where a heavy atomic nucleus, such as uranium or plutonium, splits into lighter nuclei when it absorbs a neutron. This process releases an enormous amount of energy, along with more neutrons and gamma rays. The energy released comes from the conversion of a small amount of mass into energy, as described by Einstein's famous equation \(E=mc^2\).

Now let's look at the options:

1. Energy obtained by burning 1500 tonnes of high grade coal: Burning coal is a chemical process. Even with 1500 tonnes (\(1.5 \times 10^6\) kg), the total energy produced, while large, is still limited by the energy density of the chemical bonds.
2. Energy obtained by fission of 1 kg uranium: Uranium, specifically the isotope Uranium-235, is a fissile material used in nuclear reactors. The fission of a single Uranium-235 nucleus releases approximately 200 MeV of energy. The energy released from the fission of 1 kg of Uranium-235 is immense, roughly equivalent to burning millions of kilograms of coal.
3. Energy obtained by fission of 1 kg thorium: Thorium-232 is a fertile material. It does not readily undergo fission with thermal neutrons like U-235. However, it can absorb a neutron to become Thorium-233, which then decays to Uranium-233. Uranium-233 is a fissile material that can undergo fission and release energy, similar to U-235. While 1 kg of thorium itself doesn't directly fission, it can be used in a breeder reactor cycle to produce fissile material (U-233), and the fission of this produced U-233 would yield a very large amount of energy per kg of U-233.
4. Energy obtained by burning 1500 tonnes of low grade coal: Similar to burning high grade coal, but low grade coal has less energy density, meaning burning the same amount would yield less energy than burning high grade coal.

Comparing the energy yields:

• Burning 1 kg of coal yields about \(2 \times 10^7\) Joules.
• Burning 1500 tonnes (\(1.5 \times 10^6\) kg) of high grade coal yields approximately \(1.5 \times 10^6 \times 2 \times 10^7 = 3 \times 10^{13}\) Joules.
• Fission of 1 kg of Uranium-235 yields about \(8.2 \times 10^{13}\) Joules.

The energy from fission of 1 kg of Uranium is significantly higher than burning 1500 tonnes of even high-grade coal.

Nuclear fission reactions, like the fission of 1 kg of uranium, release several orders of magnitude more energy per unit mass than chemical reactions like burning coal. Therefore, obtaining energy through nuclear fission of 1 kg of uranium will result in a much larger amount of energy production compared to burning 1500 tonnes of coal (either high or low grade) or the potential energy yield derived from 1 kg of thorium (which requires conversion to fissile material first).

Thus, the process that can result in a large amount of energy production from the given options is the energy obtained by fission of 1 kg uranium.