Bharat has achieved the first criticality at the 500 MWe "Prototype Fast Breeder Reactor" (PFBR) in the Kalpakkam nuclear power plant in Tamil Nadu on April 6, 2026. MWe means megawatt electrical. It is a unit of power. 1 MWe means one million watts of electric capacity generated by a power plant.
First criticality signals the start of the self-sustaining nuclear chain reaction and Bharat entering the second stage of the three-stage nuclear power programme as envisaged by the nuclear theoretical physicist and the father of Bharat's nuclear programme, Dr Homi Jehangir Bhabha. *
This is an essential step before the rector begins full-scale power generation. The PFBR is designed to use thorium-232, which Bharat has in abundance. It will fuel the third stage of Bharat's nuclear power programme.
This is a major step towards clean & green energy. A positive move towards "Energy Security", "Atmanirbhar Bharat", and "Viksit Bharat".
The 3 stages of Bharat's nuclear power programme are as follows: -
Stage 1: Pressurised Heavy Water Reactors (PHWRs)
2. Uranium atoms transmute*** to plutonium-239 (Pu-239) when they absorb high-energy neutrons on collision.
3. Pu-239 undergoes fission**** reaction on collision with slow-moving thermal neutrons, releasing extreme heat and more neutrons.
4. Pressurised heavy water absorbs the heat.
5. The steam produced drives the turbine. An electrical generator connected to the turbine generates electricity.
More than 18 PHWRs are generating power, which includes 220 MWe, 540 MWe, and 700 MWe units.
Stage 2: Fast Breeder Reactors (FBRs)
2. Fissile Pu-239 core is covered by a "blanket" of fertile U-238 or Th-232.
3. Pu-239 split and release fast neutrons due to fission. These neutrons are absorbed by fertile U-238 and Th-232. U-238 transmutes to more Pu-239, and Th-232 to uranium-233 (U-233).
4. FBRs use liquid sodium or liquid lead as coolant because they do not slow down the neutrons like heavy water, which is used as coolant and moderator in PHWRs.
Stage III: Thorium-Based Reactors
2. U-233 will convert a vast amount of Thorium Th-232 deposits in Bharat to more U-233, which can power not just entire Bharat but the entire world for centuries.
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* Dr Homi Jehangir Bhabha was on board Air India Flight 101, which crashed into Mont Blanc in the Alps minutes before landing in Geneva on January 24, 1966. The deep state used the CIA to orchestrate the crash in order to thwart Bharat's nuclear programme.
** Fertile vs fissile material
2. Fertile materials transmute to fissile material when they absorb high-energy neutrons on collision, whereas fissile materials can split with slow-moving thermal neutrons, releasing energy.
3. Fertile materials are used in breeder reactors to generate more fissile material than they consume.
*** Transmute means to change from one form or substance into another,
**** Unlike nuclear fusion, which combines light atoms like hydrogen and deuterium to release energy as happens inside the sun, nuclear power plants use nuclear fission, which splits heavy atoms like uranium and plutonium to release energy. Nuclear fusion releases 3-4 times more energy than nuclear fission; however, it is not yet technologically feasible to maintain 100 million degree plasma.
