[SocialMedia] Zap Energy Fusion Startup to Develop a Sodium Cooled Advance Fission Reactor - Guest Post

Social Media Attachments9:52 AM (4 hours ago) to socialmedia@list.ans.org The New York Times has a report about a new effort by ZAP Energy, which is developing a fusion energy machine, that it has plans to also develop a sodium-cooled advancer reactor. Below is the full text of the NYT report. Also attached is a white paper (PDF file) distributed by the firm about its plans. Due to the long and technically dense nature of the white paper, and as an aid to attention conservation for readers, also attached is a short executive summary (500 words) of the white paper which was provided to Neutron Bytes via an email from ZAP Energy on 04/29/30. Google Gemini Pro was used to boil the white paper down to an executive briefing format which was then edited for clarity. The original output of the AI session cited sections of the white paper for reference. & & & How to Build a Better Kind of Nuclear Power? This Side Hustle Might Help. https://nytimes.com/2026/04/29/climate/zap-energy-fusion-fission.html Raymond Zhong    April 29, 2026 Atomic fusion has long been seen as the ultimate source of clean energy because of all its advantages over fission, the process that has powered nuclear power plants for nearly eight decades. It’s safer — no chain reactions, no meltdowns. It would leave no long-lasting radioactive waste. And it would use fuels that are cheaper and more abundant, providing an attractive source of round-the-clock, emissions-free energy that could help stop climate change. Now, one leading fusion start-up has decided the best way to beat fission might be to embrace it. Zap Energy, a nine-year-old company in Everett, Wash., said on Wednesday that it had begun developing a small fission reactor, one that would be cheaper and less complex to build than existing nuclear reactors. Zap isn’t moving away from fusion, Benj Conway, the company’s president and co-founder, said in an interview. Fission and fusion are opposite processes; the former splits atoms while the latter melds them. Even so, there are commonalities in engineering that give Zap and its particular design for a fusion reactor a head start in fission, Mr. Conway said. Plus, developing fission reactors will give the company experience in obtaining regulatory approvals and building to commercial safety standards, he said. That experience will be important when the company starts building fusion plants. By pursuing fission, “we’ll be building fusion power plants much, much earlier than we would be doing otherwise,” Mr. Conway said. Zap hopes to bring its fission reactor to market in the early 2030s. Other start-ups around the country are also aiming to build small, next-generation fission reactors. But none of them started out in fusion. Electricity demand is surging as data centers multiply, and the Trump administration is encouraging new nuclear plants to play a big role in meeting it. The administration is supporting fusion development as well, and a few fusion start-ups say their experimental devices are close to producing more power than they consume, the key breakthrough that has eluded fusion machines for decades. Still, most experts say fusion remains decades away from supporting the grid at large scale. America’s best-funded fusion start-up, Commonwealth Fusion Systems, plans to build its first power plant in Virginia and turn it on the early 2030s. Helion Energy (which, like Zap, is based in Everett) is constructing a facility in eastern Washington that it says will deliver power to Microsoft in 2028. Most fusion machines use either superstrong magnets or high-power lasers to cause plasma atoms to combine and release energy. Zap is working on a simpler device, one that achieves fusion by zapping plasma with electricity. The company hopes that, with no giant magnets or lasers, its reactors will be smaller and cheaper to build. The design of Zap’s fusion reactor also shows promise for so-called hybrid nuclear systems that braid together fission and fusion. The company’s work in fission should help it develop hybrids down the road, Mr. Conway said. According to Fusion Energy Base, a website that tracks the industry, Zap has raised $330 million from investors including the oil giants Chevron and Shell, the Japanese bank Mizuho and Breakthrough Energy Ventures, a venture capital firm founded by Bill Gates. Zap’s experimental devices have crossed several technical milestones in recent years. “The fusion work’s going well, and fusion’s coming,” said Zabrina Johal, Zap’s newly appointed chief executive. “But there’s massive demand and need right now” for nuclear power, and the company can help fulfill it while continuing its core mission, Ms. Johal said. Zap isn’t the first fusion start-up with a side hustle. Some sell magnets. Others produce radioactive substances used to diagnose and treat health conditions. One start-up, Marathon Fusion, says it has developed a method for using fusion reactors to turn mercury into gold. Such efforts aren’t necessarily a sign that the prospects for fusion energy are dimming, said Sam Wurzel, the researcher who runs Fusion Energy Base. Commercial fusion is a colossal challenge, and generating revenue helps companies secure investment to fund research and development, he said. “In some ways, I see it as just responsible stewardship of investor funds.” Zap is first aiming to build a 10-megawatt fission reactor, enough to power several thousand homes. The company is targeting users like remote data centers, logistics warehouses and isolated military bases, with devices that could be built in a factory and delivered by truck, train or cargo plane. Most nuclear reactors today are cooled with highly pressurized water, but Zap’s would use liquid sodium. That would allow it to operate at lower pressures and with less shielding, helping it to be cooled more efficiently. The challenge for many first-of-a-kind reactor technologies would be cost, said Jacopo Buongiorno, a professor of nuclear science and engineering at the Massachusetts Institute of Technology. The energy such machines produce is likely to be very expensive, at least to start, he said. “It is true that data centers are willing to pay more for electricity that is carbon free and stable, and nuclear provides that,” Dr. Buongiorno said. “But how much more?” # # # Dan Yurman dan.yurman@outlook.com Mobile/Cell: 216-218-3823 https://neutronbytyes.com