Restarts, uprates & nuclear utilities

Who owns it

The gigawatts that ship this decade already exist. New large-scale nuclear in the US is a 2032+ story, and most SMR designs are unbuilt and unlicensed, so the only nuclear capacity that can serve datacenter load before 2030 is the operating fleet plus a thin pipeline of restarts and uprates. That makes the merchant-leaning nuclear owners the clearest expression of this chokepoint. Constellation (NASDAQ: CEG) owns the largest such restart: the 835 MW former Three Mile Island Unit 1, rebranded the Crane Clean Energy Center, under a 20-year PPA with Microsoft, with the in-service target pulled forward to 2027. Constellation layered on a 20-year, 1,121 MW Clinton PPA with Meta plus a 30 MW uprate. Talen Energy (NASDAQ: TLN) expanded its Amazon relationship to 1,920 MW from Susquehanna through 2042, worth up to ~$1.4B in annual revenue at full ramp. Vistra (NYSE: VST) signed a 1,200 MW Comanche Peak PPA with AWS and ~2,609 MW of Meta PJM nuclear PPAs that bundle 213/80/140 MW uprates at Perry, Davis-Besse and Beaver Valley. NextEra (NYSE: NEE) is restarting the 615 MW Duane Arnold plant under a 25-year Google PPA.

What breaks it

The constraint is physical and regulatory, not commercial. A restart is a multi-year, capital-heavy NRC proceeding: Crane runs through a dedicated NRC Restart Panel with a final decision expected in 2027, and Duane Arnold's restart hinges on NRC approval with first power not expected until early 2029 at a cost above $1.6B. Uprates are slower still: Vistra's PJM uprate energy does not begin delivery until ~2031, ramping to 2034. PPA headline MW also overstate near-term cash: Talen's full 1,920 MW is not delivered until 2032, and Vistra's AWS power ramps to full capacity by 2032. The fleet is finite — there are only a handful of restartable units and limited uprate headroom — so the chokepoint is the absence of incremental electrons, not demand.

What forces the reprice

The catalyst tape is the NRC docket and dated PPA milestones, not conference vibes. Discrete reprice events include the NRC's Crane draft EA/FONSI (issued early June 2026, comment period closing July 8) and the final EA/FONSI expected September 2026, moving toward a 2027 restart decision; Crane and Duane Arnold synchronization dates; uprate construction starts; and each new signed offtake. Earnings are amplifiers: Constellation's nuclear production tax credit provides an inflation-linked floor under the whole fleet, and management affirmed FY2026 adjusted operating EPS guidance of $11.00-$12.00 after the $16B Calpine close. Vistra posted record Q1 2026 adjusted EBITDA of $1.494B with ~3.2 GW of nuclear still uncontracted — every GW it places under a hyperscaler PPA converts merchant exposure into 20-year cash.

Be honest about size and earliness

Unlike the SMR developers, these names have real revenue today — but the datacenter-nuclear narrative is mostly future cash flow. Talen's 1,920 MW deal generates up to ~$1.4B annual revenue only once fully ramped by 2032; today it is a refueling-outage transition to front-of-the-meter delivery. Crane (2027) and Duane Arnold (2029) contribute zero electrons until those dates and remain contingent on NRC sign-off. Vistra's uprate megawatts are a 2031-2034 story. So the right framing: CEG, VST and TLN are operating-fleet cash machines (PTC-floored, hedged) onto which a multi-year restart/uprate growth option is bolted — the option, not current EBITDA, is what the datacenter PPAs price. Be especially disciplined on the SMR-adjacent language in these deals: Talen and AWS only agreed to explore SMRs and uprates, which is an MOU, not an order. NEE's restart is genuine but the holdco is a regulated-utility-plus-renewables giant where one 615 MW unit barely moves consolidated earnings — it is a sentiment and optionality story, not a needle-mover. PSEG (NYSE: PEG) belongs on the watchlist precisely because its nuclear-to-datacenter exposure is still exploratory talks and a Salem uprate, with no signed nuclear offtake. Distinguish signed PPAs (CEG/Microsoft, CEG/Meta, VST/AWS, VST/Meta, TLN/Amazon, NEE/Google) from everything else, every time. This is structure and catalysts, not advice.