Current Affairs

SMRs vs PHWRs Explained: India’s Nuclear Technology Mix Under the Nuclear Energy Mission

What Happened

As India operationalises private-sector entry into nuclear power, the conversation has pivoted to the technology mix. The Government is doubling down on two parallel tracks: legacy 220 MW Pressurised Heavy Water Reactors (PHWRs) — re-cast as Bharat Small Reactors (BSRs) for captive industrial use — and a new family of Small Modular Reactors (SMRs), including the indigenous Bharat Small Modular Reactor (BSMR-200) and SMR-55, with lead units identified for Tarapur. The Union Budget 2025-26 earmarked Rs 20,000 crore for SMR R&D under the Nuclear Energy Mission.

Why It Matters

India’s three-stage nuclear programme (Bhabha plan) is built around PHWRs (Stage I) → Fast Breeders (Stage II, PFBR Kalpakkam) → Thorium-U233 (Stage III). SMRs are an insert, not a replacement — factory-built, ≤300 MWe, deployable in remote/captive use cases (steel, cement, hydrogen). Choosing SMR vs PHWR isn’t ideological: it’s siting, financing, and time-to-grid. SMRs promise lower capex and shorter build times; PHWRs leverage India’s fuel-cycle sovereignty on natural uranium.

Key Concepts

  • PHWR — Pressurised Heavy Water Reactor; natural uranium + D2O; India’s workhorse design.
  • SMR — Small Modular Reactor (≤300 MWe per unit, IAEA definition); factory-built modules.
  • BSMR-200 / SMR-55 — indigenous SMRs being co-developed by BARC and NPCIL.
  • PFBR Kalpakkam — Prototype Fast Breeder Reactor, Stage II of three-stage programme.
  • IAEA Safeguards — 2008 India-specific framework; civilian facilities only.

CLAT Connection

GK & Science: three-stage programme, Bhabha, thorium reserves; Polity: Article 51(c) — international law and IAEA Safeguards Agreement (2008); Current Affairs: Nuclear Energy Mission 100 GW by 2047; Legal Reasoning: licensing regime under AERB, environmental clearance under EIA 2006. Likely MCQs on PHWR vs SMR, PFBR, IAEA Safeguards scope, and three-stage stages.

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