The Prototype Fast Breeder Reactor (PFBR) project in India, which is a vital component of the country's three-stage nuclear power program, has faced significant delays primarily due to "first-of-a-kind technological issues" encountered during the integrated commissioning phase, reported Government of India.

These challenges are being addressed systematically in close coordination with the reactor's designers, according to India's Atomic Energy Minister Jitendra Singh, who provided this update to the parliament in August 2025.

The PFBR, located at Kalpakkam and developed by BHAVINI under the Department of Atomic Energy, aims to be a 500 MWe sodium-cooled fast breeder reactor that significantly contributes to India's nuclear energy capacity. Construction began in 2004 with an original completion target of 2010, but the project has since experienced multiple postponements spanning over two decades.

The most recent timeline given is that the PFBR is expected to achieve criticality by March 2026 and reach full power generation by December 2026.

The commissioning process entered an important stage in August 2024 when India's Atomic Energy Regulatory Board (AERB) granted permission to proceed with the First Approach to Criticality, which involved loading the reactor core with fuel (uranium-plutonium mixed oxide) and starting low power physics tests.

Despite this progress, new technical hurdles characteristic of the reactor's pioneering technology have delayed the overall completion. The PFBR is designed to use a closed nuclear fuel cycle to optimally utilise India's limited uranium resources and abundant thorium reserves, with its spent fuel enabling second and third stages of the country's nuclear program focused especially on thorium utilisation.

India's three-stage nuclear power program, envisioned by Dr. Homi Bhabha, uses pressurised heavy water reactors (first stage) to produce plutonium, fast breeder reactors like the PFBR (second stage) to breed more fissile material, and advanced heavy water reactors utilising thorium-plutonium fuel (third stage) to achieve a sustainable thorium fuel cycle.

While the first stage has matured and fast breeder reactors like the PFBR are approaching operational status, the advanced heavy water reactor designs are still undergoing review and development.

The PFBR's delays are a result of its unprecedented technological complexities that are being systematically resolved. Once operational, it will play a crucial role in India's long-term energy security by enabling the utilisation of thorium reserves and closing the nuclear fuel cycle.

The project remains a cornerstone in advancing India’s second stage and progressing towards the third stage of its ambitious three-stage nuclear program.

Sansad News