NUCLEAR ENERGY

• Nuclear energy is the energy stored in the nucleus of an atom and is released through nuclear reactions. 
• It is a powerful source of energy used for electricity generation, medical applications, space exploration, and even nuclear weapons.

There are two main ways to release nuclear energy:

• Nuclear Fission 
• Nuclear Fusion 

Nuclear Fission (Currently Used in Nuclear Power Plants)

• Nuclear fission is a process in which a heavy atomic nucleus (like Uranium-235 or Plutonium-239) splits into smaller nuclei when bombarded by a neutron. 
• This reaction releases:
• A large amount of heat energy
• More neutrons, which continue the chain reaction
• Radioactive by-products

How Does Fission Generate Electricity?

• Fuel Rods: Uranium or Plutonium fuel is placed inside a nuclear reactor.
• Chain Reaction: Neutrons collide with fuel atoms, causing them to split and release heat.
• Heat Transfer: The heat is used to convert water into steam.
• Turbine Rotation: The high-pressure steam turns a turbine connected to a generator.
• Electricity Production: The generator converts mechanical energy into electricity.
• Cooling & Recycling: The steam is cooled and converted back into water for reuse.

Examples of Nuclear Fission Reactors

• Pressurized Water Reactor (PWR) – Used in India, USA, France, Russia.
• Boiling Water Reactor (BWR) – Used in Japan, USA.
• Fast Breeder Reactors (FBRs) – India is developing these for better fuel efficiency.

Nuclear Fusion (Future of Clean Energy)

• Nuclear fusion is a process where two light atomic nuclei (like Hydrogen isotopes: Deuterium & Tritium) combine to form a heavier nucleus (Helium), releasing an enormous amount of energy.
• Fusion occurs at extremely high temperatures (millions of degrees Celsius) and is the process that powers the Sun and stars.

Why is Fusion Not Used Yet?

• Requires extremely high temperatures and pressure to sustain.
• Scientists are working on Tokamak reactors (like ITER in France) to make fusion energy viable.

Advantages of Fusion over Fission

• No risk of nuclear meltdown
• No long-lived radioactive waste
• Abundant fuel supply (Hydrogen from water)
• Higher energy output than fission

India’s Nuclear Energy Program

• India follows a three-stage nuclear program, designed by Dr. Homi Bhabha, to maximize the use of its Thorium reserves:

Stage 1 – Pressurized Heavy Water Reactors (PHWRs)

• Uses Uranium-235 as fuel and Heavy Water (D₂O) as a moderator.
• Example: Tarapur, Kakrapar, Kaiga Nuclear Power Plants.

Stage 2 – Fast Breeder Reactors (FBRs)

• Uses Plutonium-239 produced in Stage 1.
• Example: Prototype Fast Breeder Reactor (PFBR) in Kalpakkam, Tamil Nadu.

Stage 3 – Advanced Thorium Reactors

• Uses Thorium-232, which is abundant in India, making the country self-sufficient in nuclear fuel.
• Still under development.

India’s Nuclear Power Plants

• Operational Plants: Tarapur (Maharashtra), Kudankulam (Tamil Nadu), Kalpakkam (Tamil Nadu), Kaiga (Karnataka), Kakrapar (Gujarat), Rawatbhata (Rajasthan).
• Upcoming Plants: More reactors planned to reach 22 GW capacity by 2030.

International Collaborations

• Indo-US Nuclear Deal (2008): Allowed India to engage in civilian nuclear trade despite not being part of the Non-Proliferation Treaty (NPT).
• Agreements with Russia (Rosatom), France (Areva), and Japan for nuclear technology.

Advantages of Nuclear Energy

• High Energy Output – A small amount of uranium produces massive energy.
• Low Carbon Emissions – Helps in climate change mitigation.
• Reliable Power Supply – Unlike solar and wind, nuclear power is available 24/7.
• Thorium Potential – India has world’s largest thorium reserves, making it energy-secure.

Challenges & Risks of Nuclear Energy

• Nuclear Waste Disposal – Spent fuel remains radioactive for thousands of years.
• Nuclear Accidents – Past disasters like Chernobyl (1986), Fukushima (2011), and Three Mile Island (1979) raise safety concerns.
• High Initial Cost – Setting up nuclear power plants requires huge investment.
• Risk of Proliferation – Nuclear technology can be used for making weapons.

Future of Nuclear Energy

• Small Modular Reactors (SMRs) – Compact, cost-effective, and safer nuclear reactors.
• Fusion Energy Projects – ITER (France), DEMO (Europe), and China’s Experimental Reactor aim to make fusion a reality.
• Advanced Breeder Reactors – Enhance fuel efficiency and reduce waste.