Why doesn't India build small modular reactors?

As of 2026, only two nations on Earth run a commercial small modular reactor. Russia has operated a floating plant since 2020; China has connected its HTR-PM to the grid. India, for all its ambition in nuclear power, is not yet on that list. It has designs, a budget line, and two proposed sites — but no prototype under construction.

A small modular reactor is a nuclear plant shrunk and standardised. Instead of a single large custom-built unit, the idea is a reactor small enough to be factory-fabricated, shipped, and assembled — producing a few tens to a couple of hundred megawatts each. The appeal is deployment: siting plants where a large reactor cannot go, and building them faster by repetition. The difficulty is that shrinking a reactor does not shrink the physics or the safety engineering. Every joint, vessel, and control system must meet the same standards as a full-scale plant, and the economics only work if the design can genuinely be repeated. Getting from a paper design to a licensed, operating unit is the hard part, which is why so few have crossed it.

India is at the design stage, and it is pursuing three routes at once. The Bhabha Atomic Research Centre (BARC) is developing the 200 MWe Bharat Small Modular Reactor (BSMR-200), built on pressurised water reactor technology; the 55 MWe SMR-55; and a 5 MWt high-temperature gas-cooled reactor intended to be coupled with a chemical process for hydrogen production. The BSMR-200 is being jointly designed with the Nuclear Power Corporation of India Limited (NPCIL), and is in an advanced stage of obtaining financial and administrative sanction. Lead units are proposed at Tarapur in Maharashtra and BARC's Vizag campus in Andhra Pradesh.

The money is committed. The 2025-26 Union Budget allocates Rs 20,000 crore — around USD 2.5 billion — to operationalise at least five indigenously designed SMRs by 2033. This sits inside a larger goal: 100 GWe of nuclear capacity by 2047, with SMRs deployed alongside large reactors rather than replacing them.

The gap, then, is not one of intent or funding but of stage. India has done the design work; it has not yet built. NPCIL's own estimate places BSMR-200 construction at 60 to 72 months after approvals are granted — five to six years from a sanction that is still pending. That is the honest distance between an emerging capability and an operating one.

Why does the gap persist? Because an SMR is not a single invention but a stack of capabilities that must all be in place at once. India's foundations here are uneven but real. Pressurised water reactor technology, which underpins the BSMR-200 and SMR-55, is a producing capability. Nuclear pressure vessel fabrication — the manufacturing of the reactor's core containment component — is also a producing capability. The high-temperature gas-cooled route for hydrogen is itself still emerging, mirroring the SMR programme as a whole. The design competence exists; what has not yet been demonstrated is the integration of these pieces into a licensed, buildable, repeatable unit.

What it would take is now largely a matter of execution rather than discovery. The BSMR-200 needs its financial and administrative sanction; the first units need to break ground at Tarapur and Vizag; and the multi-year construction clock needs to start and finish. The distinctive promise of the SMR — repeatability — is only proven once a second and third unit follow the first at lower cost and shorter schedule. India has assembled the designs, the budget, and the sites. The climb ahead is turning that into steel, fuel, and a working reactor.