NuScale holds the certificate. GE Hitachi is holding the shovel...
That is the contrast the SMR business community needs to sit with. NuScale Power spent a decade and hundreds of millions of dollars becoming the first, and still only, company with an NRC-certified small modular reactor design in the United States. It is a genuine, hard-won achievement. But certification was never the finish line, it was the starting gun. And right now, in Ontario, in Tennessee, and in Poland, it is GE Vernova Hitachi Nuclear Energy’s BWRX-300 that is out of the blocks first, pouring concrete, boring tunnels, and clearing regulatory hold points while much of the industry is still watching from the sidelines.
If you’re allocating capital, signing supply contracts, or making a ten-year bet on which SMR platform actually gets built at scale, that distinction should be reordering your priority list right now.
The Design Philosophy That Skipped the Hard Part
The BWRX-300’s core advantage isn’t marketing. It’s lineage. Rather than inventing a new reactor class from scratch, GE Hitachi took its NRC-licensed Economic Simplified Boiling Water Reactor and shrank it, stripping out pumps, valves, and safety systems the smaller design doesn’t need. Ontario Power Generation describes the result as a “10th generation design” built on decades of real-world boiling water reactor operating experience, using fully passive natural circulation cooling instead of active pumped systems. It is evolutionary engineering, not experimental engineering. That single choice is why GE Hitachi is years ahead on the one metric that actually matters in this industry: getting steel in the ground.
Where the Concrete Is Already Poured
Here is what “ahead” looks like in practice, as of mid-2026.
At OPG’s Darlington site in Ontario, the first of four planned BWRX-300 units is under active construction, not planning, not permitting, construction. Excavation of the reactor building shaft has reached roughly 80 percent completion, basemat modules are being fabricated and assembled on site, and a massive tunnel boring machine, nicknamed Harriet Brooks, has already arrived and begun work. In March 2026, Canada’s nuclear regulator lifted the project’s first regulatory hold point after verifying the reactor building foundation commitments were met. This is on pace to be the first grid-connected SMR in the Western world, targeted for completion before the end of the decade.
In the United States, TVA’s Clinch River project just cleared a milestone no other American SMR developer has reached. In June 2026, NRC staff formally recommended that the Commission issue a construction permit for a BWRX-300 at the Clinch River site in Oak Ridge, Tennessee, the first advanced reactor construction permit application of its kind to reach this stage of review. The mandatory hearing was scheduled for August 13, 2026, months ahead of the original December timeline. If the permit is granted, Clinch River becomes the first licensed SMR construction site in America, full stop.
And the fleet ambitions extend well past North America. Poland’s Orlen Synthos Green Energy has committed to a multi-unit BWRX-300 program, explicitly citing the Darlington construction milestone as validation that “the technology we have chosen is ready for commercial deployment.” In the United Kingdom, the design has already cleared Step 2 of the Office for Nuclear Regulation’s generic design assessment, with regulators finding no fundamental safety, security, or environmental shortfalls.
Certification proves a design can work on paper. Construction proves it can survive contact with reality, with concrete suppliers, labor unions, regulators, and municipal politics. GE Hitachi is the only Western SMR developer currently running that gauntlet in public, in real time.
The Uncomfortable Math for Competitors
None of this means the BWRX-300 is cheap or that first-of-a-kind risk has vanished. Early GE Hitachi pricing pointed to roughly $2,250 per kilowatt for the design; OPG’s actual delivered cost for the Darlington fleet has landed meaningfully higher, with officials projecting average power costs near 14.9 cents per kilowatt-hour once the four-unit build is complete. That gap between marketing-deck economics and utility-financed reality is a lesson every SMR investor should already have priced in.
But here is the thought-provoking part. OPG is not financing this with a NuScale-style consortium of small municipal utilities pooling scarce capital. It is a large, investment-grade provincial utility funding construction from its own cash flow, generating-station revenue, and debt, with Ontario ratepayers absorbing the cost over time through their bills. That is a fundamentally sturdier financing architecture than the one that killed the Carbon Free Power Project in Idaho. GE Hitachi didn’t just design a better reactor. Its early customers appear to have learned the financing lesson NuScale’s did not, and learned it before the failure, not after.
What This Means for the Business Community
The SMR race is no longer a single-horse story about first certification. It is now, visibly, a construction race, and GE Hitachi’s BWRX-300 currently has the only Western SMR poured into a foundation. For utilities, EPC contractors, component manufacturers, and capital allocators, the practical question has shifted from “which design is certified” to “which design is being built by customers with balance sheets strong enough to finish what they start.” On that question, right now, the BWRX-300 has separation.
Whether that lead holds, whether cost overruns catch up with it the way they caught NuScale, and whether Clinch River clears its NRC hearing on schedule, are the open questions that will define capital flows in this sector for the rest of the decade. Betting exclusively on the company that got certified first, while ignoring the company that is actually building, is a risk few serious investors in this space can still afford to take.
Track Every Move Before Your Competitors Do
Construction milestones, regulatory hold points, and fleet decisions like Poland’s are moving fast enough now that quarterly headlines aren’t enough to build a position on. The SMR Market Intelligence Report 2027 tracks the full competitive landscape, BWRX-300, NuScale, and the rest of the field, with the forecasts and financing analysis serious SMR decision-makers need heading into 2027. It’s worth the download.
