On 17 June 2026, the Department of Atomic Energy (DAE) reported that its Secretary and Atomic Energy Commission (AEC) Chairman, Dr Ajit Kumar Mohanty, visited the Tarapur Atomic Power Station (TAPS) in Maharashtra. TAPS Units 1 & 2, commissioned in 1969, are the world's oldest operating commercial nuclear power reactors, and the Atomic Energy Regulatory Board (AERB) has cleared a roughly 10-year life extension for them. The visit was framed as a symbol of India's journey from technology acquisition to genuine self-reliance.
Why Tarapur Matters
Tarapur was India's first commercial nuclear power station, built in the 1960s with US collaboration (under a 1963 agreement, with General Electric supplying the reactors) as Boiling Water Reactors (BWRs) — making Units 1 & 2 the only BWRs in India, while the rest of the fleet is predominantly indigenous PHWRs (Pressurised Heavy Water Reactors). The station later added Units 3 & 4 (indigenous 540 MW PHWRs, commissioned 2005–06). The original US fuel-supply link became strained after India's 1974 "Smiling Buddha" Pokhran-I test triggered Western technology-denial regimes, forcing India to indigenise the fuel cycle — which is exactly why these reactors running today on Indian-managed fuel symbolise the "acquisition to self-reliance" arc. That such reactors remain safely operational after more than five decades — now under management by the Nuclear Power Corporation of India Ltd (NPCIL) — is a testament to Indian engineering and regulatory competence. The AERB life-extension nod, granted only after rigorous Periodic Safety Reviews, reflects India's maturity in operating, maintaining and refurbishing ageing nuclear assets without foreign dependence. It is worth recalling that nuclear power supplies only about 3% of India's electricity today (roughly 8 GW of installed capacity across about two dozen reactors), yet the long-term ambition — to reach 100 GW of nuclear capacity by 2047 via the three-stage route — makes every operating reactor strategically valuable. This narrative of "acquisition to self-reliance" mirrors the Aatmanirbhar theme aspirants track on our NDA current-affairs hub.
Homi Bhabha's Three-Stage Nuclear Programme
The heart of the topic — and a perennial exam favourite — is the three-stage nuclear power programme conceived by Dr Homi Bhabha, designed to exploit India's modest uranium but vast thorium reserves:
- Stage 1 — Pressurised Heavy Water Reactors (PHWRs): use natural uranium as fuel and heavy water (D₂O) as both moderator and coolant; produce power and plutonium-239 as a by-product. This is the mature, operational stage and the backbone of India's current fleet.
- Stage 2 — Fast Breeder Reactors (FBRs): use the plutonium-239 from Stage 1 (as mixed-oxide fuel), blanketed with thorium-232 / depleted uranium, to "breed" more fissile fuel (uranium-233) than they consume. The Prototype Fast Breeder Reactor (PFBR), a 500 MWe sodium-cooled reactor at Kalpakkam, anchors this stage. The bridging logic is key: India's uranium is scarce (~1–2% of world reserves) but its thorium is among the largest on Earth, so Stage 2 exists to convert non-fissile thorium into fissile U-233.
- Stage 3 — Thorium-based reactors: leverage India's huge thorium reserves, using the U-233 bred in Stage 2, with the Advanced Heavy Water Reactor (AHWR) as the planned platform. This is the long-term goal that would give India near-energy-independence.
India's thorium is concentrated in the monazite sands of the beach placers of Kerala (notably around Kollam/Chavara), Odisha, Andhra Pradesh and Tamil Nadu.
Memorise the institutional map too. The DAE (Department of Atomic Energy) — set up in 1954, working directly under the Prime Minister — sets policy; the AEC (Atomic Energy Commission) is the apex decision body; BARC (Bhabha Atomic Research Centre, Trombay, Mumbai) is the premier R&D hub; NPCIL operates the power plants; BHAVINI is the special company set up to build the fast breeder reactors; and the AERB (Atomic Energy Regulatory Board, constituted 1983) is the independent safety regulator. The whole programme operates under the Atomic Energy Act, 1962. India's geography candidates can deepen this through our note on energy and economic geography.
Doctrine, Diplomacy and the Strategic Angle
Nuclear power and nuclear strategy are linked in the GK syllabus. India's nuclear doctrine (formalised in 2003) rests on Credible Minimum Deterrence, a declared No First Use (NFU) policy, "massive retaliation" to any nuclear strike, and civilian (political) control of the arsenal via the Nuclear Command Authority. On the civil side, the India-US Civil Nuclear Deal (2008) — also called the 123 Agreement — and the subsequent Nuclear Suppliers Group (NSG) waiver (granted in 2008, the only such country-specific waiver) ended India's nuclear isolation and reopened access to fuel and technology. This was significant because India is NOT a signatory to the Non-Proliferation Treaty (NPT, 1968), which India rejects as "discriminatory" for dividing the world into nuclear "haves" and "have-nots"; India is also not a party to the CTBT. As part of the deal, India agreed to separate its civil and military nuclear facilities and place the civil ones under IAEA safeguards. India is now a member of three of the four export-control regimes — the MTCR, Wassenaar Arrangement and Australia Group — but NSG membership is still blocked (largely by China). Candidates should also place the major plants: Kudankulam (Tamil Nadu, Russian VVER, India's largest), Kakrapar (Gujarat, home to the indigenous 700 MW PHWRs), Rawatbhata (Rajasthan), Narora (Uttar Pradesh), Kaiga (Karnataka) and Kalpakkam (Tamil Nadu, the fast-breeder hub). For a structured walk-through of these linkages, see the upcoming Cavalier courses in Delhi.
The Physics Examiners Test: Fission, Moderators and Reactor Parts
NDA's General Science section pairs the institutional story with reactor physics, so a few fundamentals are worth locking. A nuclear reactor releases energy through controlled nuclear fission — the splitting of a heavy nucleus (such as U-235 or Pu-239) by a neutron, releasing energy and 2–3 fresh neutrons that sustain a chain reaction. The key components and their roles are perennial single-mark items: the fuel (uranium/plutonium); the moderator (slows fast neutrons to thermal speeds so they can cause further fission — commonly heavy water, ordinary/light water or graphite; recall that India's PHWRs use heavy water, while the Chernobyl-type RBMK used graphite); the control rods (made of neutron-absorbing materials like boron or cadmium, inserted to slow or stop the reaction); and the coolant (carries away heat to raise steam that drives a turbine). A breeder reactor is special because it produces more fissile material than it consumes. Contrast all of this with nuclear fusion (joining light nuclei, the Sun's process, still experimental on Earth via projects like ITER, to which India is a partner) — a classic fission-versus-fusion distinction.
Naturally Occurring Radioactivity and Strategic Minerals
The thorium story connects to a wider minerals-and-geography theme. Thorium is extracted from monazite, a phosphate sand mineral, while uranium in India comes chiefly from Jaduguda in Jharkhand (the Singhbhum belt) and newer reserves in Andhra Pradesh (Tummalapalle). Beryllium, zirconium and graphite are other strategic nuclear-grade minerals. India's domestic uranium scarcity is the single most important reason the three-stage thorium route exists — a cause-and-effect link examiners reward. The applications of radioactivity extend beyond power: radioisotopes are used in medicine (cobalt-60 for cancer therapy, technetium in diagnostics), agriculture (mutation breeding, food preservation) and industry/dating (carbon-14 dating). BARC's broader mandate covers all of this. For aspirants, the takeaway is that the Tarapur news is a doorway into an interconnected cluster — reactor physics, the fuel cycle, strategic minerals and the diplomacy of non-proliferation — exactly the kind of integrated knowledge the GAT rewards.
🎯 Practice MCQs
Q1. TAPS Units 1 & 2, commissioned in 1969, hold the distinction of being: (a) India's largest reactors (b) the world's oldest operating commercial nuclear reactors (c) India's first fast breeder reactors (d) the world's first thorium reactors → (b) — They are the world's oldest operating commercial nuclear power reactors.
Q2. In Homi Bhabha's three-stage programme, Stage 1 reactors (PHWRs) primarily use: (a) enriched uranium (b) plutonium (c) natural uranium (d) thorium → (c) — PHWRs use natural uranium and produce plutonium as a by-product.
Q3. The Prototype Fast Breeder Reactor (PFBR), central to Stage 2, is located at: (a) Tarapur (b) Kalpakkam (c) Kudankulam (d) Rawatbhata → (b) — The PFBR is at Kalpakkam, Tamil Nadu.
Q4. Which body is the independent nuclear safety regulator in India? (a) DAE (b) NPCIL (c) AERB (d) BARC → (c) — The Atomic Energy Regulatory Board (AERB) is the regulator; NPCIL operates plants and BARC handles R&D.
Q5. Stage 3 of India's nuclear programme is designed to exploit reserves of which element, found in monazite sands? (a) Uranium (b) Plutonium (c) Thorium (d) Beryllium → (c) — Thorium, abundant in the monazite sands of Kerala and Odisha.
Q6. In a nuclear reactor, the function of the moderator (e.g. heavy water or graphite) is to: (a) absorb neutrons to stop the reaction (b) slow down fast neutrons to sustain fission (c) cool the reactor core (d) shield against radiation → (b) — The moderator slows fast neutrons to thermal speeds; control rods (boron/cadmium) absorb neutrons.
Q7. India has chosen NOT to sign which treaty, terming it "discriminatory"? (a) Paris Agreement (b) Non-Proliferation Treaty (NPT) (c) Montreal Protocol (d) Kyoto Protocol → (b) — India is not a signatory to the NPT (1968) or the CTBT.
Q8. The Department of Atomic Energy (DAE) was established in which year and functions under whom? (a) 1948, under the Defence Ministry (b) 1954, directly under the Prime Minister (c) 1962, under the Science Ministry (d) 1974, under the AEC → (b) — The DAE was set up in 1954 and works directly under the Prime Minister.
📋 How this gets asked (PYQ pattern)
The three-stage programme is one of the most heavily recurring science topics in NDA and CDS GK papers — typically as a match-the-stage-to-its-fuel item, a "which reactor type uses natural uranium" question, or a thorium/monazite link. Examiners also test the institutional map (DAE 1954 vs AEC vs BARC vs NPCIL vs BHAVINI vs AERB 1983), reactor physics (moderator, control rods, coolant, fission vs fusion), plant locations (Kudankulam, Kakrapar, Kalpakkam, Jaduguda for uranium), and the NPT/CTBT/NSG-waiver/2008-deal diplomacy angle, including India's MTCR/Wassenaar/Australia Group memberships. The fresh 2026 hook — Tarapur's life extension and its "world's oldest operating reactor" tag (commissioned 1969, US-origin BWRs) — supplies a current-affairs entry point that can pin a static topic to a dated event, exactly the blend examiners increasingly favour.
Master nuclear current affairs with The Cavalier. Static science gains marks only when paired with the latest developments — follow our NDA current-affairs hub and explore the upcoming Cavalier courses in Delhi to lock down the science, geography and strategic-affairs syllabus with ex-Army faculty.
✍️ Written by Col Vijyanat Thakur — Veteran, Indian Army; SSB & defence-studies faculty at The Cavalier. Reviewed by the Cavalier Faculty Desk.
The Cavalier, founded by ex-Army officers, has trained NDA/CDS/SSB aspirants since 2001 (Facebook · YouTube).
Source: Department of Atomic Energy PIB release, 17 June 2026 (PRID 2274057). Facts cross-verified.