Overview
On 6 April 2026, Prime Minister Narendra Modi announced on X that the PFBR has attained criticality. This is the first time a fast breeder reactor in India has reached a self‑sustaining nuclear reaction, paving the way for larger scale use of indigenous thorium resources.
Key Developments
- PFBR reached criticality after fuel loading on 18 October 2025.
- Design capacity: 500 MWe with a projected life of 40 years.
- Six additional 600 MW fast breeder units (FBR‑600) are planned, with twin units to be co‑located at Kalpakkam.
- The FRFCF is slated for completion by December 2027.
Important Facts
India’s nuclear fleet currently comprises 18‑20 PHWRs, totalling about 7.48 GW(e). These reactors generate the plutonium needed for the second stage, where fast neutrons in the PFBR convert fertile U‑238 into fissile Pu‑239. The ultimate goal is to breed U‑233 from abundant thorium‑232.
The PFBR uses MOX fuel and a blanket of U‑238. Its coolant is liquid sodium, which allows fast neutrons to persist but requires stringent leak‑prevention measures.
UPSC Relevance
The achievement illustrates India’s strategic push for energy security and nuclear self‑reliance, a frequent topic in GS III (Science & Technology). Understanding the three‑stage programme is essential for questions on energy policy, indigenous technology development, and the link between civilian nuclear power and strategic capabilities. The role of the AERB in granting commercial operation permission highlights regulatory frameworks, relevant to GS III and GS II (Governance).
Way Forward
Before commercial operation, the PFBR must undergo low‑power tests and receive AERB approval. Parallel construction of the FRFCF will enable closed‑fuel‑cycle operations, reducing dependence on imported enriched uranium. Successful scaling of FBR‑600 units will accelerate the transition to the third stage, leveraging India’s vast thorium reserves to achieve long‑term energy security.