PARLIAMENT QUESTION: INDIGENOUS PHWR

1. At a Glance

• PHWR (Pressurised Heavy Water Reactor) = India's workhorse nuclear reactor design using natural uranium fuel and heavy water (D₂O) as moderator/coolant; the 700 MWe indigenous PHWR is the largest domestically designed variant. [1][2]
• Centre to a flagship "fleet mode" programme of 10 × 700 MWe PHWRs sanctioned in June 2017, anchoring the Nuclear Energy Mission targeting 100 GW by 2047. [2]
• UPSC relevance: GS-III (Energy, Science & Tech, Indigenisation), Prelims (NPCIL/DAE/AERB, reactor sites). [1]

2. Why in the News

• PIB Parliament Question (12 Feb 2026, DAE) stated all 10 fleet-mode 700 MWe PHWRs are at various pre-project stages; 3 are operational, 1 under commissioning, 2 under construction. [1]
• NPCIL added 2,100 MW capacity since Dec 2022 via KAPS-3, KAPS-4, RAPS-7; logged highest-ever generation of 56,681 MU in FY 2024-25. [1]
• RAPS-7 began commercial operation on 15 April 2025 — 3rd indigenous 700 MWe PHWR. [3]

3. Background & Evolution

• PHWR lineage traces to RAPS-1 (Rajasthan, 1973) built with Canadian collaboration; full indigenisation matured through 220 MWe and 540 MWe designs (Tarapur 3&4, 2005-06). [2]
• June 2017: Union Cabinet's bulk approval of 10 × 700 MWe PHWRs in fleet mode — first time bulk sanction in India's nuclear history. [2]
• 2020-21: KAPS-3 (Kakrapar, Gujarat) achieved first criticality (Jul 2020), commercial ops Jun 2023 — first indigenous 700 MWe PHWR. [2]
• 2023-24: KAPS-4 commercial ops; RAPS-7 criticality Sept 2024, full power and commercial ops April 2025. [3]

4. Core Static Facts

• Parent body: Department of Atomic Energy (DAE), under PMO directly. [1]
• Implementing PSU: Nuclear Power Corporation of India Ltd (NPCIL). [1]
• Regulator: Atomic Energy Regulatory Board (AERB). [3]
• Enabling law: Atomic Energy Act, 1962. [2]
• Fleet mode sites (10 reactors): Kaiga 5&6 (Karnataka), Chutka 1&2 (MP), Gorakhpur (GHAVP) 3&4 (Haryana), Mahi Banswara 1-4 (Rajasthan). [2]
• Under construction: RAPS-8 (Rawatbhata), GHAVP-1&2 (Gorakhpur, Haryana). [2]
• Operational 700 MWe PHWRs: KAPS-3, KAPS-4, RAPS-7 (= 2,100 MW). [1]
• FY 2024-25 NPCIL generation: 56,681 Million Units (record). [1]
• 2047 target: 100 GW nuclear capacity (Nuclear Energy Mission). [2]

5. Multi-Dimensional Analysis

Scientific / Technological

• Full indigenisation of major reactor components and fuel assembly fabrication of 700 MWe PHWR. [1]
• Design uses natural uranium + heavy water, avoiding enrichment dependence — strategic given India is outside NPT. [2]
• Incorporates passive safety systems (Steel-lined Inner Containment, Passive Decay Heat Removal). [3]

Economic

• Standardisation + bulk procurement of long-lead equipment with staggered delivery — cuts time and cost. [1]
• Boost to domestic heavy-engineering ecosystem (L&T, BHEL, Walchandnagar). [1]

Strategic / Geopolitical

• Reduces reliance on imported LWRs (Russian VVER, French EPR, US AP1000); insulates from CSC liability friction. [2]
• Supports three-stage nuclear programme (Stage-1 PHWR → Stage-2 FBR → Stage-3 Thorium). [2]

Environmental

• Low-carbon baseload; NPCIL emission avoidance cited in Year-End Review 2025. [1]
• Aligned with Panchamrit climate commitments (500 GW non-fossil by 2030). [2]

Administrative

• Fleet mode replaces project-by-project sanction → faster financial closure, single design template. [1]

6. Recent Developments

• 12 Feb 2026 — DAE Parliament reply: status of 10 fleet PHWRs, 56,681 MU FY25 record. [1]
• 15 Apr 2025 — RAPS-7 commercial operation begins. [3]
• Sept 2024 — RAPS-7 attains first criticality. [3]
• 2023 — KAPS-3 commercial operation (first indigenous 700 MWe PHWR). [2]
• Year-End Review 2025 (DAE) — reaffirmed 100 GW by 2047 goal. [2]

7. Prelims Hooks

• PHWR uses natural uranium fuel and heavy water as both moderator and coolant. [2]
• NPCIL — PSU under DAE, NOT under Ministry of Power. [1]
• AERB is the nuclear safety regulator (set up 1983 under AE Act 1962). [3]
• Fleet mode sanction year: 2017 (10 reactors, 7,000 MW). [2]
• First indigenous 700 MWe PHWR: KAPS-3, Kakrapar (Gujarat). [2]
• RAPS-7 commercial ops: 15 April 2025. [3]
• NPCIL FY 2024-25 generation: 56,681 MU (highest ever). [1]
• Mahi Banswara site (Rajasthan) hosts 4 × 700 MWe under fleet mode. [2]
• GHAVP = Gorakhpur Haryana Anu Vidyut Pariyojana (Fatehabad district). [2]
• India's 2047 nuclear target: 100 GW. [2]
• RAPS-1 (1973) was India's first PHWR (Canadian-aided). [2]

8. Mains Relevance

• GS-III: Energy security; Science & Technology — indigenisation, achievements of Indians in S&T.
• GS-II: Government policies and interventions (fleet-mode approval).
• Probable stems:
• "Discuss the strategic significance of India's indigenous 700 MWe PHWR fleet-mode programme in achieving the 100 GW nuclear target by 2047."
• "India's three-stage nuclear power programme remains relevant despite global shift toward SMRs. Comment."
• "Examine how 'fleet mode' procurement is transforming the economics of nuclear power in India."

9. Related Topics to Study Next

• Three-Stage Nuclear Programme (Bhabha plan) — PHWR is Stage-1 backbone.
• Bharat Small Reactors (BSRs) & SMRs — Budget 2024-25 nuclear mission component.
• PFBR Kalpakkam — Stage-2 fast breeder, criticality milestone 2024-25.
• Civil Nuclear Liability Act, 2010 — affects foreign reactor imports.
• IAEA & NSG — India's safeguards regime post-2008 waiver.
• AERB & nuclear regulation — independence debate.
• Atomic Energy Act, 1962 — proposed amendments to allow private sector.
• India's energy mix & Panchamrit targets — context for nuclear scaling.

10. Common Errors / Trap Areas

• PHWR ≠ LWR (Kudankulam is VVER LWR, not PHWR; uses enriched uranium + light water).
• NPCIL sits under DAE/PMO, not Ministry of New & Renewable Energy or Ministry of Power.
• Fleet sanction = 2017, not 2015 or 2019.
• First indigenous 700 MWe PHWR is KAPS-3 (Gujarat) — not RAPS-7.
• "Heavy water" is D₂O (deuterium oxide), not tritium-rich water.
• Mahi Banswara is in Rajasthan, not Gujarat (despite the Mahi river link).