Joined January 2024
6 Photos and videos
W. Robb Stewart retweeted
The Most Overlooked Opportunity in Nuclear? Why Nuclear Power Plant Uprates Beat Everything Else in the Race for New Capacity. Recent conversations about the budding nuclear renaissance often begin with the same list. Microsoft restarting Three Mile Island, tech companies partnering with advanced nuclear reactor vendors or the proposed Japanese funded US AP1000 fleet build. These announcements generate headlines, volatile valuations and investor decks. Meanwhile, forty Westinghouse pressurized water reactors (PWR) sit at roughly the same thermal power output they were commissioned at decades ago, operating within design margins calculated on transistorized computers before integrated circuits existed. Together, these plants hold between 6-10GW of additional capacity, the equivalent of eighteen to thirty 300MW SMRs, that could be unlocked faster and cheaper than any other nuclear source and perhaps even faster than new gas. My conversation with returning guests Robb Stewart (@nuclear_robb) and James Krellenstein (@jbkrell), CTO and CEO of Alva Energy (@alvaenergyio), made the case that power uprates at existing PWR plants represent the lowest-hanging fruit in the sector, bypassing the megaproject risks and nuclear supply chain rebuilding that make new nuclear construction so daunting for utilities. The components turn out to be far more manageable and anticlimactic than new build nuclear: non-safety-related secondary side equipment such as feedwater heaters and condenser tube bundles, alongside nuclear-grade steam generators that the fleet has already learned to replace during their month long scheduled outages using well-rehearsed industrial choreography. Alva’s approach avoids the traditional uprate bottleneck by building a separate standardized 250MW Second Turbine Generator Plant (2TGP) building diverting incremental steam from an uprated core without touching the existing turbine centerline. Most of the construction happens on a conventional, non nuclear island using mature supply chains and firm fixed price engineering, procurement, and construction contracts, leaving the outage window limited to a short tie in during a normal refueling cycle. Compared to a cohort of first of a kind nuclear steam supply system startups that accessed public markets through SPAC mergers and achieved substantial valuations in the hundreds of millions on compelling nuclear narratives this approach sounds deliberately boring. But perhaps boring is what our current moment demands. The question is whether the American nuclear zeitgeist can resist the allure of novelty long enough to pluck the low hanging gigawatts hiding in plain sight.
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W. Robb Stewart retweeted
In the AI age: Economic Capacity = Power capacity. The US has under delivered for many years on power expansion. Power is the limiting factor for the AI era. @alvaenergyio unlocks gigawatts of clean, always-on nuclear from existing plants -- faster, lower cost, and at scale.
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W. Robb Stewart retweeted
Exclusive: The startup Alva Energy says it knows how to kick-start the slumbering nuclear-power industry—and former Intel CEO Pat Gelsinger is backing its efforts on.wsj.com/4bN5SZ7
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W. Robb Stewart retweeted
Applications for the Activate Fellowship open on September 9— and we have two upcoming webinars to help you get ready! September 9: Learn about the Entrepreneurial Fellowship Opportunity September 10: Activate Application 101 #1 Register below: activate.org/events
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Learning-by-doing, the sought after but never achieved cost-reduction path for new nuclear. Let's unpack some key factors that @Dr_Keefer and I discussed on @DecoupleMedia:
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At Alva, our view is that with proper upfront planning, all 3 can actually be done at the FOAK. This is why we see the FOAK ABWR as the fastest nuclear build in world history.
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This complicates the theory of learning rates, but its good news for the future of nuclear. We should have high expectations for FOAK projects. They can be done well! History proves this.
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W. Robb Stewart retweeted
Everyone says nuclear power is over-regulated. With word of the big nuclear EOs looming, I spent a few weeks talking to people in the nuclear industry to find out which reforms they thought would be most helpful, and which they were nervous about. Here are the top 12 (a🧵...)
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Taking a closer look at this study shows that ~100 MWe is best, if you only plan to deploy 1000 MWe total. The DOE goal is 200 GWe, 2000X more! Same study shows at 10 GWe demand, large nuclear is best.
24 Apr 2025
What is the ideal reactor size to power a 1 GW data center? Too big, and you don’t have enough redundancy to offer high availability. Too small, and you take too large of a hit on scale economies. 100 MW reactors could be the optimal longterm, according to this study (attached below). Aalo is starting with 50 MW plants & 10 MW reactors, as this size can also be economical, while being more venture fundable. Full study here: mdpi.com/1996-1073/17/20/507…
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New essay from @TedNordhaus argues the optimal nuclear technology for liberal markets (not state sponsored co's) is unknown/unknowable, and therefore we must advocate for an "all of the above" set of technologies.
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But I don't see many advocating for milestone funding except Kairos, to their enormous credit.
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Coming back to Ted's piece, I wonder if the same "nuclear underpants" theory applies to his logic. "Just build them all and see what works best." OK, but how, with what capital, on what timeline, at what risk, at what opportunity cost?
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