Nuclear startup Terrestrial Energy goes public via SPAC, netting $280M in merger

Terrestrial Energy, a small nuclear startup, merged with an acquisition company on Wednesday. 

The North Carolina-based company is developing small modular reactors and expects to net $280 million from the deal. Before the SPAC merger, Terrestrial Energy had raised $94 million, according to PitchBook. The combined entity expects to list on Nasdaq under the symbol IMSR.

The ticker is a reference to Terrestrial Energy’s flavor of small modular reactor (SMR), which it calls an integral molten salt reactor. In such a device, uranium fuel is mixed with various salts, such as lithium fluoride or sodium fluoride, that serve to suspend the nuclear fuel and act as the reactor’s main coolant.

Terrestrial Energy’s reactor core is designed to be entirely replaced every seven years, in part to head off some of the problems earlier molten salt reactors experienced like corrosion. The reactor core includes not only the fuel and graphite modulators that regulate the speed of the fission reactions, but also the heat exchangers and pumps that keep the salt cool and flowing.

The startup is targeting a range of markets, including electric power, data centers, and industrial applications that require heat.

There are many extant proposals to build commercial-scale molten salt reactors, but to date, none have been built. The basic technology was invented in the 1950s, but two experiments from that era were plagued with problems.

Nuclear power has received renewed attention as electrification of buildings and transportation, coupled with the rapid growth of data centers, has sent electricity demand soaring. 

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Tech companies have become increasingly interested in the technology as a possible solution to the electricity requirements of AI training and inference. Google, Meta, Amazon, and OpenAI’s Sam Altman have all picked a horse in the race to develop advanced nuclear reactors.

Terrestrial Energy isn’t the first SMR startup to SPAC — the Altman-backed Oklo completed its deal in 2024 — and given current hype around nuclear power, it’s possible it won’t be the last.