IDAHO FALLS, Idaho — When Bill Gross decided to chase nuclear fusion dreams three years ago, he knew the optics might be tricky. Here was a serial cleantech entrepreneur—best known for incubating solar startups—pivoting to fission at a moment when data centers are devouring electricity faster than utilities can string new transmission lines.
But Gross wasn't alone in his calculation. On February 19, NuCube Energy, the nuclear microreactor venture he co-founded with former Idaho National Laboratory scientist Cristian Rabiti, announced it had secured $13 million in fresh capital. The round, led by Arizona Nuclear Ventures with backing from Emission Reduction Corporation and members of the Walton family, underscores a broader market shift: nuclear, once the third rail of climate tech investing, is suddenly fashionable again.
Or maybe it's just necessary.
Power-Hungry AI Meets Power-Scarce Grids
NuCube's pitch hinges on a straightforward problem. Goldman Sachs warned in February 2025 that global data center electricity consumption could jump 165 percent by decade's end compared to 2023 baselines—a surge driven almost entirely by artificial intelligence infrastructure. McKinsey, in a separate analysis, projected the U.S. could face a power shortfall exceeding 15 gigawatts if new generation doesn't materialize quickly.
Enter the microreactor: small, modular, theoretically deployable without the decade-long lead times and multibillion-dollar price tags that have doomed larger nuclear projects. NuCube's DeccaCell design promises up to 15 megawatts of baseload power using TRISO fuel pellets and heat pipes—no turbines, no moving parts. Factory-built, road-transportable, capable (the company claims) of running for thirty years with minimal intervention.
It sounds almost too tidy. And perhaps it is. The DeccaCell reactor exists primarily on paper and in simulations; no independent testing has yet validated its performance specs or manufacturing feasibility.
Arizona Stakes Its Claim
John Schreiber, a general partner at Arizona Nuclear Ventures who now sits on NuCube's board, framed the investment as something larger than a single startup bet. Speaking alongside state economic development officials, he positioned Greater Phoenix as an emerging center for advanced nuclear innovation—a narrative local leaders have embraced with notable enthusiasm.
The involvement of Rob Walton and Jordan Rose Walton (yes, that Walton family) lends the round a degree of credibility, as does participation from Marin Katusa's Emission Reduction Corporation. But the regional angle is worth noting. Arizona has been courting nuclear developers aggressively, hoping to secure both energy security and a foothold in what could become a lucrative manufacturing sector—if, that is, microreactors ever move beyond the demonstration phase.
Crowded Field, Uncertain Timelines
NuCube will use the fresh capital to fund materials testing, design refinement, and the delicate dance of engaging with the Nuclear Regulatory Commission. The company signed a memorandum of understanding with Utah San Rafael Energy Lab last year to site a test reactor in Orangeville, Utah—a small step, but a concrete one. Shell GameChanger provided strategic backing in mid-2025, though the specifics of that partnership remain vague.
More interesting is the January 2025 deal with Energy Vault, which plans to integrate NuCube's NuSun microreactor platform with its battery storage and energy management systems. The target? Data center deployments by late 2028 or early 2029. That timeline feels both ambitious and slightly arbitrary, given that NuCube's technology hasn't yet entered demonstration trials.
The competition is fierce and better-capitalized. Westinghouse's eVinci microreactor cleared a critical NRC licensing hurdle in March 2025. Radiant and Oklo have collectively raised hundreds of millions. NuCube, by contrast, lists fewer than ten employees on LinkedIn and traces its founding to 2023. The company joined Halliburton Labs in late 2024, receiving an undisclosed investment aimed at accelerating commercialization—though "accelerating" may be relative in a sector where regulatory approval alone can consume years.
The Gross Factor
Bill Gross carries weight in cleantech circles, even if his track record is mixed. His involvement signals that sophisticated investors see nuclear microreactors as more than hype. But betting on simplified reactor designs and expedited regulatory pathways is, to put it mildly, optimistic. The NRC doesn't move quickly. Nor do supply chains for specialized nuclear components.
Cristian Rabiti, NuCube's co-founder and chief technical architect, brings deep domain expertise from his years at Idaho National Laboratory. That pedigree matters—microreactor startups are littered with talented engineers who underestimated the gap between prototype and commercial viability.
What NuCube has working in its favor is timing. Data centers need power now, not in 2035. Utilities are desperate for baseload alternatives that don't depend on natural gas or require thousands of acres for solar farms. If NuCube can navigate the regulatory gauntlet and prove its reactor works as advertised, there's a genuine market waiting.
The "if" is doing a lot of work in that sentence. And investors, it seems, are willing to pay $13 million to find out whether it holds.
