Before Barnard Construction installed a single safety-related pier at Kairos Power’s Oak Ridge campus, its crews had already drilled 70 of them into a building nobody will ever operate.
That is the whole idea. Kairos runs what it calls engineering test units, nonnuclear full-scale mockups built alongside the real thing, and the third one exists partly so pier crews can make their mistakes somewhere the NRC isn’t watching. Engineering News-Record detailed the approach on August 26.
Practice piers before safety-related piers
Hermes 1 needs 51 safety-related drilled piers, each six feet in diameter, running about 40 feet down to bedrock. Miss on one of those and the rework is a licensing problem, not just a schedule problem.
So Kairos built a full-scale test pier first. Then it put 70 more into the engineering test unit. By the end of that run crews were turning out up to six piers a day. The real 51 went in behind a workforce that had already done the work at volume.
What repeatability actually costs
The obvious objection is that Kairos paid to build something twice. The less obvious answer is that this is what every other manufacturing sector does before a production run, and nuclear construction in the United States has historically skipped it. Vogtle’s first units are the reference case, and the industry has spent a decade explaining that first-of-a-kind cost overruns are structural rather than fixable.
Barnard is GC on both Hermes 1 and the larger Hermes 2, which has Google and TVA on the offtake side. Having the same builder on both reactors is the other half of the argument: the learning has to stay in the same crews to be worth anything.
Why the order book makes this urgent
More than 70 gigawatts of U.S. nuclear is now on order, and almost none of it has an established construction cost basis. Whoever proves that a second unit costs meaningfully less than the first one owns a lot of heavy-civil work in the 2030s.
The pier data is small, but it is the kind of number that shows up in a bid. Six piers a day on a practice building is a productivity rate somebody can hold a subcontractor to.
The same logic shows up in heavy civil without the reactor. Halmar‘s Park Avenue Viaduct replacement in Manhattan runs the same prefabricated superstructure sequence 28 times over 28 weekends, and the productivity gain across those cycles is why the program landed roughly $195 million under budget.