Nuclear Energy: Fission, Fusion, Indian Reactors & Pokhran

Nuclear energy is a regularly tested topic in Kerala PSC science and GK sections. Questions cover fission vs fusion, India’s nuclear programme, key reactors, and nuclear tests. The tables below cover all exam-essential facts.

1. Nuclear Fission vs Nuclear Fusion

Feature	Fission	Fusion
Definition	Splitting of a heavy nucleus into lighter nuclei	Combining light nuclei to form a heavier nucleus
Energy released	Large	Much larger (about 4 times per unit mass)
Fuel	Uranium-235, Plutonium-239	Hydrogen isotopes (Deuterium, Tritium)
Temperature required	Can occur at lower temperatures	Extremely high (millions of degrees) — thermonuclear
Occurs in	Nuclear reactors, atomic bombs	Sun and stars, hydrogen bombs
Waste	Radioactive waste (major concern)	Minimal radioactive waste
Control	Can be controlled in reactors	Not yet controlled for power generation
Commercial use	Yes (nuclear power plants)	Experimental stage (ITER project)

2. Key Terms

Term	Definition
Radioactivity	Spontaneous emission of particles/energy from unstable atomic nuclei
Discovered by	Henri Becquerel (1896)
Types of radiation	Alpha, Beta, Gamma
Half-life	Time for half the radioactive atoms to decay
Critical mass	Minimum amount of fissile material needed for a sustained chain reaction
Chain reaction	One fission triggers further fissions in a self-sustaining process
Moderator	Slows down neutrons (heavy water, graphite)
Coolant	Removes heat from reactor core (water, heavy water, liquid sodium)
Control rods	Absorb excess neutrons to control reaction rate (Cadmium, Boron)

3. India’s Three-Stage Nuclear Programme

Stage	Fuel	Reactor Type	Status
Stage 1	Natural Uranium (U-238/U-235)	Pressurised Heavy Water Reactor (PHWR)	Operational (multiple reactors)
Stage 2	Plutonium-239 (from Stage 1 spent fuel)	Fast Breeder Reactor (FBR)	Prototype FBR at Kalpakkam (under commissioning)
Stage 3	Thorium-232 / Uranium-233	Advanced Heavy Water Reactor (AHWR)	R and D stage

Conceived by: Dr. Homi Jehangir Bhabha

Rationale: India has limited uranium but vast thorium reserves (world’s largest, about 25% of global reserves, mainly in Kerala and Odisha monazite sands).

4. Major Nuclear Power Plants in India (NPCIL)

Plant	Location (State)	Reactor Type
Tarapur Atomic Power Station (TAPS)	Tarapur, Maharashtra	BWR (oldest) + PHWR
Rajasthan Atomic Power Station (RAPS)	Rawatbhata, Rajasthan	PHWR
Madras Atomic Power Station (MAPS)	Kalpakkam, Tamil Nadu	PHWR
Narora Atomic Power Station (NAPS)	Narora, Uttar Pradesh	PHWR
Kakrapar Atomic Power Station (KAPS)	Kakrapar, Gujarat	PHWR
Kaiga Generating Station	Kaiga, Karnataka	PHWR
Kudankulam Nuclear Power Plant	Kudankulam, Tamil Nadu	VVER (Russian-designed PWR)

Fact	Detail
Oldest nuclear plant	Tarapur (1969)
NPCIL	Nuclear Power Corporation of India Limited
Total installed nuclear capacity	About 8,180 MW (as of 2024)
Share of nuclear in total electricity	About 3%

5. Important Nuclear Organisations in India

Organisation	Full Form	Function
DAE	Department of Atomic Energy	Apex body; directly under PM
BARC	Bhabha Atomic Research Centre (Mumbai)	Nuclear research; Dhruva reactor
NPCIL	Nuclear Power Corporation of India Ltd	Operates nuclear power plants
AERB	Atomic Energy Regulatory Board	Safety regulation
IGCAR	Indira Gandhi Centre for Atomic Research (Kalpakkam)	Fast breeder reactor research
UCIL	Uranium Corporation of India Ltd	Uranium mining (Jaduguda, Jharkhand)

6. India’s Nuclear Tests

Test	Code Name	Date	Location	Details
Pokhran-I	Smiling Buddha	18 May 1974	Pokhran, Rajasthan	Peaceful nuclear explosion; PM Indira Gandhi
Pokhran-II	Operation Shakti	11 and 13 May 1998	Pokhran, Rajasthan	5 tests; PM Atal Bihari Vajpayee; led by APJ Abdul Kalam and R. Chidambaram

Fact	Detail
India’s nuclear doctrine	No First Use (NFU); credible minimum deterrence
Nuclear Command Authority	Chaired by PM; Political Council (decision) + Executive Council (execution)
India-US Civil Nuclear Agreement	2008 (123 Agreement); ended India’s nuclear isolation
NSG (Nuclear Suppliers Group)	India not a member; seeking membership
NPT (Non-Proliferation Treaty)	India has not signed (considers it discriminatory)
CTBT (Comprehensive Nuclear-Test-Ban Treaty)	India has not signed

7. Key Scientists in India’s Nuclear Programme

Scientist	Contribution
Homi J. Bhabha	Father of India’s nuclear programme; established TIFR and AEET (now BARC)
Vikram Sarabhai	Father of Indian space programme; also contributed to atomic energy
Raja Ramanna	Led Pokhran-I (1974)
R. Chidambaram	Led Pokhran-II (1998)
APJ Abdul Kalam	Missile and nuclear programme; 11th President of India
Anil Kakodkar	Former Chairman, Atomic Energy Commission; advanced thorium programme

8. Radioactivity Discoveries

Discovery	Scientist	Year
Radioactivity	Henri Becquerel	1896
Radium and Polonium	Marie Curie and Pierre Curie	1898
Neutron	James Chadwick	1932
Nuclear fission	Otto Hahn and Fritz Strassmann	1938
First controlled chain reaction	Enrico Fermi	1942
First atomic bomb (Trinity test)	Manhattan Project (USA)	1945

9. Nuclear Energy — Advantages and Challenges

Advantages	Challenges
Low carbon emissions	Radioactive waste disposal
High energy density	High initial cost
Reliable base-load power	Risk of accidents (Chernobyl 1986, Fukushima 2011)
Reduces fossil fuel dependence	Uranium supply limitations (for India)
Small land footprint	Public opposition and safety concerns

10. Previous Year Question Patterns

• “Father of India’s nuclear programme?” — Homi J. Bhabha
• “Pokhran-I code name?” — Smiling Buddha
• “Pokhran-II was in which year?” — 1998
• “India’s nuclear doctrine?” — No First Use
• “Oldest nuclear plant in India?” — Tarapur (1969)
• “BARC is located at?” — Mumbai (Trombay)
• “Thorium reserves in India are mainly in?” — Kerala and Odisha (monazite sands)
• “Moderator in PHWR?” — Heavy water
• “Kudankulam reactor type?” — VVER (Russian PWR)