RAPP-8 Fuel Loading & India’s Thorium Path |...

CURRENT AFFAIRS | 21 SEPTEMBER 2026

At 15:18 hours on 19 September 2026, the Nuclear Power Corporation of India Limited (NPCIL) began Initial Fuel Loading (IFL) at Unit 8 of the Rajasthan Atomic Power Project (RAPP-8) at Rawatbhata, Rajasthan. RAPP-8 is a 700 megawatt-electric (MWe) indigenous Pressurised Heavy Water Reactor (PHWR). According to the NPCIL statement, reported by The Indian Express and Business Today on 20 September, fuel loading began only after the Atomic Energy Regulatory Board (AERB) granted permission following “rigorous safety evaluations, major system integrity audits and site readiness reviews”. The reactor is expected to begin commercial operation during the current financial year.

The same edition of The Indian Express carried an interview with Anil Kakodkar, former Chairman of the Atomic Energy Commission, arguing that India should bring thorium-based fuel into its PHWR fleet earlier than the classical three-stage plan envisages. Read together, the two stories explain where India’s nuclear programme stands: a standardised indigenous reactor is now being built in fleet mode, while a debate has opened on how quickly India can move towards its large thorium resources.

What happened at RAPP-8

Initial Fuel Loading is the stage at which fuel bundles are first placed in the reactor core. NPCIL said the loading was carried out in the presence of its Director (Operations), Director (Projects) and the Site Director of the Rawatbhata Rajasthan Site. It described the next steps: the First Approach to Criticality (FAC), which marks the start of a controlled fission chain reaction, followed by the start of power generation. The Indian Express noted that the process from initial fuel loading to commercial operation typically takes about six to eight months.

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RAPP-8 is the fourth reactor in a series of 16 indigenous 700 MWe PHWRs being set up in the country. The first two, Units 3 and 4 of the Kakrapar Atomic Power Station (KAPS) in Gujarat, began commercial operation in 2023–24. RAPP-8’s twin, RAPP-7, followed in April 2025. NPCIL said the milestone strengthens the standardisation of the 700 MWe design and supports its deployment in fleet mode: building many identical units so that design, procurement and construction lessons carry over from one unit to the next.

The Indian Express also reported that geotechnical investigations for Units 9 and 10 at Rawatbhata began on the same day. Apart from RAPP-8, NPCIL has eight other reactors under construction: two each at Gorakhpur (Haryana) and Kaiga (Karnataka), and four at Kudankulam (Tamil Nadu). According to Business Today’s report of the NPCIL statement, the corporation operates 24 reactors with 8.78 GWe of capacity. It has 17 more reactors, about 13 GWe, at various stages of implementation, and aims to supply over half of India’s 100 GWe nuclear target for 2047.

Background & Framework

How a PHWR works. A pressurised heavy water reactor uses natural uranium as fuel, in which the fissile isotope uranium-235 makes up only about 0.7%. It uses heavy water (deuterium oxide) as both moderator and coolant. Because heavy water absorbs very few neutrons, the reactor can run without enriched fuel. This matters for a country that, for decades, had limited access to enrichment services and international fuel markets. India’s PHWR line began with RAPS-1 at Rawatbhata, built with Canadian collaboration in the early 1970s. It was then scaled up indigenously to 220 MWe, 540 MWe and now 700 MWe units.

The legal framework. For six decades the sector was governed by the Atomic Energy Act, 1962, which reserved nuclear power generation for the Government and its companies such as NPCIL. That changed with the Sustainable Harnessing and Advancement of Nuclear Energy for Transforming India (SHANTI) Act, 2025. It was introduced in the Lok Sabha on 15 December 2025, passed by the Lok Sabha on 17 December and by the Rajya Sabha on 18 December, and received Presidential assent on 20 December 2025. According to PRS Legislative Research, the SHANTI law replaces both the Atomic Energy Act, 1962 and the Civil Liability for Nuclear Damage Act, 2010. It allows licensed private companies and joint ventures to build, own or operate nuclear plants, gives statutory recognition to the AERB (which had until then functioned without a statute of its own), and replaces the single liability cap of ₹1,500 crore with a graded cap of ₹100 crore to ₹3,000 crore depending on plant capacity.

The three-stage programme and Kakodkar’s thorium argument

India’s long-term nuclear strategy is the three-stage nuclear power programme conceived by Homi Jehangir Bhabha in the 1950s. Stage one uses natural-uranium PHWRs, which produce electricity and also generate plutonium in their spent fuel. Stage two uses fast breeder reactors (FBRs) fuelled by that plutonium; with a thorium blanket, they breed the fissile isotope uranium-233. The first of these is the 500 MWe Prototype Fast Breeder Reactor (PFBR) at Kalpakkam. Stage three is meant to run on the thorium–uranium-233 cycle, which would let India use its thorium resources, which Kakodkar called the world’s largest, for centuries.

Kakodkar now holds the posts of Chancellor of the Homi Bhabha National Institute and Chairman of the Rajiv Gandhi Science & Technology Commission. His argument runs as follows. Global uranium resources used in once-through mode can sustain only about 550–750 GWe of capacity (assuming a 60-year reactor life). The World Nuclear Association, by contrast, projects about 1,400 GWe of nuclear capacity by 2050. Because most countries are reluctant to recycle uranium, he expects a supply–demand mismatch that could affect India within 10–15 years. Fast reactors remain essential, but he estimates a gap of two to three decades before they can be deployed in fleet mode.

His proposed bridge is to use HALEU–thorium fuel in existing PHWRs. HALEU is high-assay low-enriched uranium, uranium enriched above the usual reactor grade but below 20% uranium-235. According to Kakodkar, this can be done “without any significant design change”. It opens an earlier, parallel path to irradiating thorium at scale, while reducing spent-fuel inventory and saving uranium. He expects this to enable the third stage, with thorium molten salt reactors, in about 15 years. He also argued that, after the SHANTI Act, domestic PHWRs should form a major share of the 100 GWe nuclear mission up to 2047, with imported light water reactors making up most of the rest. Fuel recycling, he stressed, must remain with the Government.

The CLAT Angle

This topic can be tested in three ways. First, straight GK: which regulator permitted fuel loading (AERB); where RAPP is (Rawatbhata, Rajasthan); what reactor type RAPP-8 is (700 MWe PHWR); which units came first in the 700 MWe series (KAPS-3 and 4); and which law replaced the Atomic Energy Act, 1962 (the SHANTI Act, 2025). Second, legal reasoning: a passage on the SHANTI Act could ask whether a private operator can recover compensation from a supplier of defective equipment. PRS notes that the Act removes the operator’s right of recourse on that ground and keeps it only for contractual rights and deliberate harmful acts. Questions on graded liability, licensing and an independent regulator are natural fits. Third, critical reasoning: Kakodkar’s interview is an argument with a clear structure. The premise is a uranium shortage, the intermediate conclusion is that FBRs will come too late, and the recommendation is HALEU–thorium in PHWRs. A question could ask which statement would most weaken it, for example evidence that FBR fleet deployment is closer than two decades.

Analysis: why the 700 MWe fleet matters

The significance of RAPP-8 lies less in one reactor than in the series. Nuclear projects worldwide have been slowed by one-off designs, cost overruns and long construction times. A standardised design built repeatedly is the usual answer, because each unit shortens the learning curve for the next. With KAPS-3 and 4 and RAPP-7 already in commercial operation, RAPP-8 is a test of whether the fleet can keep a steady pace. The start of groundwork for Units 9 and 10 at the same site suggests that Rawatbhata is being developed as a multi-unit hub.

There are, however, clear tensions. First, scale: 8.78 GWe of operating NPCIL capacity is a long way from a 100 GWe target by 2047. Closing that gap requires much faster construction, the private and foreign participation the SHANTI Act now allows, and small modular reactors. Under the Nuclear Energy Mission announced in the Union Budget 2025–26, ₹20,000 crore was set aside for research and development of SMRs, with at least five indigenously developed SMRs to be operational by 2033, according to PIB. Second, fuel: PHWRs run on natural uranium, much of which India imports, so Kakodkar’s warning about global supply goes to the heart of the fleet plan. Third, governance: opening the sector to private operators increases the importance of a strong and independent regulator. That is why the AERB’s new statutory footing is a significant institutional change.

Key Facts

Event: Initial Fuel Loading at RAPP Unit 8 began at 15:18 hrs on 19 September 2026.
Operator: Nuclear Power Corporation of India Limited (NPCIL), a public sector company.
Location: Rawatbhata, Rajasthan (Rajasthan Atomic Power Project, Units 7 & 8).
Reactor: 700 MWe indigenous Pressurised Heavy Water Reactor, which uses natural uranium with heavy water as moderator and coolant.
Regulator: Atomic Energy Regulatory Board (AERB), which gave permission after safety evaluations and audits.
Next steps: First Approach to Criticality, then power generation; commercial operation expected this financial year.
Series: 4th of 16 indigenous 700 MWe PHWRs, after KAPS-3 and 4 (commercial 2023–24) and RAPP-7 (April 2025).
Under construction (besides RAPP-8): 2 at Gorakhpur (Haryana), 2 at Kaiga (Karnataka), 4 at Kudankulam (Tamil Nadu).
SHANTI Act, 2025: assent on 20 December 2025; replaces the Atomic Energy Act, 1962 and the Civil Liability for Nuclear Damage Act, 2010.
Targets: 100 GW of nuclear capacity by 2047; at least 5 indigenous SMRs by 2033 under the ₹20,000 crore Nuclear Energy Mission.
Three stages: PHWR (natural uranium) → Fast Breeder Reactor (plutonium; PFBR, Kalpakkam) → thorium–U-233 reactors.

The bigger picture

Taken together, the fuel loading at Rawatbhata and the thorium interview show a programme that is expanding while also rethinking its long-term path. The classical three-stage plan was a sequence: build PHWRs, then breeders, then thorium reactors. Kakodkar’s proposal would run these stages in parallel rather than strictly one after another, using the growing PHWR fleet as the first large platform for thorium. Whether that happens will depend on HALEU supply, fuel qualification and regulatory approval. None of these is settled, and aspirants should treat the proposal as a policy argument, not an adopted decision.

Memory Hook / Mnemonic

“R-8 at 3:18”: RAPP-8 fuel loading began at 15:18 hrs on 19 September. For the 700 MWe order, remember “K-K-R-R”: KAPS-3, KAPS-4, RAPP-7, RAPP-8. For the three stages, remember “P-F-T”: PHWR, Fast breeder, Thorium, or “Please Feed Thorium”. And for the new law: SHANTI replaced two, the 1962 Act and the 2010 liability law.