PFBR at Kalpakkam achieves criticality: India second after Russia with commercial-scale FBR
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UPSC has already asked about this. Read the story with these questions in mind.
- Prelims 2012To meet its rapidly growing energy demand, some opine that India should pursue research and development on thorium as the future fuel of nuclear…Solve with answer →
- Mains 2026 · GS3Distinguish between a Fast Breeder Reactor (FBR) and a thermal nuclear reactor. In the context of first indigenously developed prototype FBR at Kalpakkam, explain…See model answer →
The indigenous 500 MWe Prototype Fast Breeder Reactor at Kalpakkam, Tamil Nadu, reached first criticality on 6 April 2026. Designed by IGCAR and built by BHAVINI, it uses uranium-plutonium MOX fuel and breeds more fuel than it burns. It starts stage two of India’s three-stage nuclear programme; India will be second after Russia to run a commercial-scale fast breeder.
- Reactor
- Prototype Fast Breeder Reactor (PFBR), 500 MWe
- Where
- Kalpakkam, Tamil Nadu
- First criticality
- 6 April 2026, 08:25 PM
- Design
- IGCAR (DAE R&D centre)
- Built by
- BHAVINI, a PSU under DAE
- Fuel
- Uranium-Plutonium Mixed Oxide (MOX); U-238 blanket
- Coolant
- Liquid sodium
The Prototype Fast Breeder Reactor: what happened?
India has little uranium but a lot of thorium. To use thorium, India first needs fast reactors that breed plutonium and, later, uranium-233. The PFBR is that bridge. That is why its first criticality is a big step.
- Criticality means the start of a controlled fission chain reaction.
- AERB gave clearance after a detailed safety review.
- Fast neutrons convert U-238 in the blanket into fissile Pu-239, so the reactor makes more fuel than it uses.
- Later the blanket can hold Thorium-232, which turns into U-233 for stage three.
- Closed fuel cycle: nuclear material is recycled, cutting waste.
- Russia alone runs commercial fast breeders now; experimental fast reactors in the USA, UK, France, Japan, Germany and China are mostly shut.
What are the three stages of India’s nuclear programme?
| Stage | Reactor | Fuel idea |
|---|---|---|
| 1 | Pressurised heavy water reactors | Natural uranium; produce plutonium |
| 2 | Fast breeder reactors (PFBR) | MOX fuel; breed Pu-239 from U-238, later U-233 from thorium |
| 3 | Thorium-based reactors | U-233 from thorium |
What else is planned in nuclear power?
- Target of 100 GW nuclear capacity by 2047.
- A Nuclear Mission with ₹20,000 crore plans five Small Modular Reactors by 2033.
- The SHANTI Act allows greater private sector participation.
How does a breeder make more fuel?
- MOX fuel in the core undergoes fission
- Fast neutrons escape into the U-238 blanket
- U-238 absorbs neutrons and becomes Pu-239
- Pu-239 is recovered and reused as fuel
- Later: Th-232 blanket gives U-233 for stage three
Why does the Prototype Fast Breeder Reactor matter?
| Angle | What to note |
|---|---|
| Energy security | Stretches limited uranium and opens the door to thorium. |
| Technology | Indigenous design, sodium coolant and a closed fuel cycle. |
| Climate | Clean, steady power for the Net Zero by 2070 goal. |
| Strategic | Puts India among very few countries with this capability. |
What are the challenges in the Prototype Fast Breeder Reactor?
- Sodium-cooled reactors need very careful safety handling.
- The project took a long time; full operation is still ahead.
- Moving to stage three needs more fast reactors and thorium fuel cycle work.
What should be done next on the Prototype Fast Breeder Reactor?
- Raise power in steps to full commercial operation.
- Plan more fast reactors and SMRs under the Nuclear Mission.
What can Prelims ask on the Prototype Fast Breeder Reactor?
- PFBR: 500 MWe, Kalpakkam; IGCAR design; BHAVINI built.
- First criticality: 6 April 2026.
- Fuel MOX; coolant liquid sodium; U-238 blanket; later Th-232.
- Nuclear Mission: ₹20,000 crore; five SMRs by 2033.
- Target 100 GW nuclear by 2047.
How to write about the Prototype Fast Breeder Reactor in Mains
Practice question (15 marks, 250 words): The Prototype Fast Breeder Reactor is the bridge to India’s thorium future. Explain the three-stage nuclear programme and the significance of the PFBR.
- Intro: uranium scarcity, thorium wealth.
- Three stages explained.
- PFBR features: MOX, breeding, sodium, closed cycle.
- Significance: energy, technology, climate.
- Challenges and way forward (SMRs, private role).
How to use this in Mains
- As per PIB (2026-04-27): the 500 MWe Prototype Fast Breeder Reactor at Kalpakkam reached first criticality on 6 April 2026; India will be the second country after Russia operating a commercial-level fast breeder reactor.
- The fast breeder is stage two of India's nuclear plan, and it is the route to using thorium later.
Quotable data pointThe 500 MWe Prototype Fast Breeder Reactor at Kalpakkam reached first criticality on 6 April 2026.
PIB: DAE: PFBR, 27 Apr 2026
Exam angle
Prelims: three-stage programme.
Practice MCQs
Original practice questions (not PYQs).
With reference to the Prototype Fast Breeder Reactor (PFBR), consider the following statements:
1. It uses uranium-plutonium mixed oxide fuel.
2. It is cooled by heavy water.
3. It was built by BHAVINI.
Which of the statements given above are correct?
Answer (c) & explanation
PIB (DAE), 7 April 2026: MOX fuel; liquid sodium coolant; built by BHAVINI.
In the PFBR, the fertile material placed in the blanket that converts into Plutonium-239 is
Answer (b) & explanation
PIB (DAE), 7 April 2026.
Questions students ask about this
What is the PFBR?
The 500 MWe Prototype Fast Breeder Reactor at Kalpakkam, Tamil Nadu. It reached first criticality on 6 April 2026.
Why is it called a breeder reactor?
It produces more fissile fuel than it consumes, by turning U-238 in its blanket into Pu-239.
Which stage of India's nuclear programme does PFBR start?
The second stage, which leads to the thorium-based third stage.
Who designed and built the PFBR?
IGCAR designed it; BHAVINI, a PSU under DAE, built and commissioned it.
Which country runs commercial fast breeder reactors today?
Only Russia. India will be second once the PFBR is fully operational.
Keep studying
Go deeper
Official source: PIB: DAE: PFBR, 27 Apr 2026
facts from cited sources only; faculty review pending