In April 2026, a new 500 MW sodium-cooled reactor in Kalpakkam, India, attained criticality. The reactor maintained a nuclear chain reaction—which is a pretty big step for any new nuclear plant. There are a number of things that struck us about this news. The haters and skeptics will point out that this unit began construction in 2004 with a 2010 expected completion date. No cost escalation figures were provided by the Indian government. But the real question here is why a molten salt reactor? It’s not a new technology. President Jimmy Carter canceled construction of one, the Clinch River Project, in 1973. And at least twelve countries have built variants of this design. The US version was built and operated in Oak Ridge, TN.
The answer to the why is thorium. In terms of natural resources, India is uranium-poor but abundant in thorium resources. And the government said as much in the press release discussing the new reactor. So we see this choice of nuclear technology as being in large measure motivated by ready access to domestically sourced thorium. In terms of the energy trilemma, a thorium-based nuclear cycle is 1) sustainable (no carbon emissions), 2) affords security of supply, 3) we’ll punt on affordability. So, two out of three ain‘t bad. But it was also the way the Indian government went about it. The design is entirely domestic, coming from the Indira Gandhi Center for Atomic Research, which is funded by the government’s Department of Atomic Energy. More broadly, the Indian nuclear program resembles that of Korea or France in terms of its policy thoroughness and application of government expertise. There are six discrete steps or functions in every nuclear program: mining, refining, project design, construction, operations, and waste remediation, and the Indians seem to be taking all of them seriously. By way of contrast, the US abandoned all federal efforts to create a nuclear waste repository early in the Obama administration, and our energy administrators haven’t thought about it seriously since. Although, in all fairness, the Indians haven’t picked a site for long-term geological storage of nuclear waste either.
