After years in the wilderness, this is a good time to be a nuclear startup.

“For the first half decade that I told people I was doing nuclear, I had to convince them, ‘Hey, here’s why nuclear is important,'” Bret Kugelmass, founder and CEO of Last Energy, told TechCrunch. “Now everyone just comes to us saying, ‘Oh yes, of course nuclear is a key part of the solution.’ I was like, okay, well, I’m glad it’s all caught up now.

Last Energy builds small modular reactors — compact nuclear power plants that can be mass-manufactured to keep costs down. The company’s reactors are designed to produce 20 megawatts of electricity, enough to power roughly 15,000 homes.

It has momentum. Last Energy recently closed a $100 million Series C led by Astera Institute with participation from AE Ventures, Galaxy Fund, Gigafund, JAM Fund, The Haskell Company, Ultranative, Woori Technology, and others.

The company has joined a number of nuclear startups that have raised funding in recent months, fueled by insatiable electricity demand in data centers. Powered by Google-backed X-Energy $700 million last month, as Antares rises $96 million two weeks ago. And in August, Aalo Atomics was raised $100 million to build his prototype reactor.

What sets Last Energy apart from competitors is its approach: the company uses an old reactor design that was developed by the government decades ago. The initial design for the pressurized water reactor was built for NS Savannahthe world’s first nuclear powered merchant ship. The ship’s power plant is about one-tenth the size of Last Energy’s planned commercial reactor. Kugelmass said the company’s updated design should produce 20 megawatts of electricity.

The company started out smaller, though. First, Last Energy built a 5-megawatt pilot reactor on a site it leased from Texas A&M. The new funding will fully fund the pilot project and help the company begin delivering its first commercial products, Kugelmass said. Last Energy hopes to turn on the pilot reactor next year, with its 20-megawatt commercial-scale unit entering production in 2028.

The reactor at the start of Last Energy was not designed to be serviced throughout its life. Instead, Last Energy permanently wraps each core in 1,000 tons of steel. Kugelmass estimated the metal would be worth about $1 million. “Most people think concrete is cheaper,” he said. “But not if it’s nuclear grade concrete.”

The reactors will arrive at the site containing six years worth of uranium. Apart from the electrical and control connections, there are no other penetrations that can break the steel wall. The heat from the fission reactions heats the steel, and the water flowing through the pipes outside harvests the heat to spin a steam turbine.

When the reactor’s time is up, Last Energy will leave it on site, with the steel room serving as a waste dump, eliminating the need for separate disposal.

The hope is that this approach, combined with manufacturing improvements, will lower the price of nuclear power. Kugelmass does not commit to a single price, instead pointing to other industries that halve the price for every tenfold increase in production.

“I don’t think it’s good with nuclear because there’s always going to be some additional fixed costs that you have with nuclear in terms of some special regulations, but that’s the kind of trend you’re going to see,” he said. “We don’t think in ones and twos, we think in tens of thousands.”