If a Reactor Sits on a Data Center Campus, Who's Actually on the Hook?

The tech company buys the power. It doesn't sign for the reactor.

Here's the thing I assumed going in, and got wrong. When you read that Microsoft is restarting Three Mile Island, or that Amazon parked a data center next to the Susquehanna plant, or that Google signed up with Kairos for a fleet of little molten-salt reactors, it sounds like the tech company owns the reactor. It mostly doesn't.

What they signed is a power deal. They're a customer. The company that actually holds the license from the Nuclear Regulatory Commission — the one legally called the "operator" — is the nuclear outfit: Constellation, Talen, Kairos, or a startup like Oklo that plans to build the reactor, keep it, and just sell you the electricity. So the reactor can literally sit on a private campus and still not belong to the company whose logo is on the building.

That split matters, because when a reactor has a bad day, the law doesn't go looking for who's richest. It goes looking for who signed.

There's a 70-year-old law that decides this, and it points at one door

It's called the Price-Anderson Act, and Congress just re-upped it all the way to 2065, so it's not going anywhere. In plain English it does two things. It forces every reactor operator to carry a big private insurance policy up front. And it funnels the liability for an accident onto that operator no matter whose fault it was — the parts supplier, the builder, the software, doesn't matter. One door. The operator's.

Above that first policy, the industry backstops itself. Every large reactor in the country has to chip in after a serious accident, and stacked together that pool climbs to something like sixteen billion dollars for a single incident. It's a clever setup: the operators insure each other, so no single company has to carry the whole nightmare alone.

Which sounds airtight. And for the big grid reactors, it more or less is. The problem is the reactors everyone's actually excited about aren't the big ones.

The line item that's missing is the one nobody wants to price

Here's where the commenter's point landed for me. The small modular reactors being pitched for data centers are, by design, small — often under a hundred megawatts. And under the rules, a reactor that small doesn't have to carry the big-reactor insurance. It carries a much smaller primary policy, and the total liability the law caps it at is roughly five hundred and sixty million dollars.

Sit with that number for a second, because it's the one worth doing arithmetic on. A serious accident at a real reactor does not politely stop at half a billion in damage — I couldn't find anyone willing to swear it would, and history doesn't suggest it. So there's a gap between what a small reactor is required to cover and what a genuinely bad day could cost. And a fleet of little reactors under that threshold isn't even paying into the big sixteen-billion-dollar pool. So who covers the gap? The honest answer I kept landing on: past a point, the federal government. The taxpayer.

That's the missing line item. It's not that the analysts are hiding it. It's that it's genuinely hard to put a dollar figure on, so it just quietly falls off the spreadsheet. A nuclear reactor is the only tenant that shows up to the lease with a 40-year government co-signer stapled to the back. Nobody prices the co-signer, because pricing it means admitting the cheap power isn't fully paid for by the people using it.

Follow the rest of the rabbit hole

I started this trying to answer one commenter's question and ended up somewhere I didn't expect: the power looks cheap partly because the worst-case bill is parked somewhere off the invoice. That's the kind of thread we love pulling on.

The reactor liability question is one stop in a much bigger story — the gas turbines, the transformers, the water, the grid strain, and the very real question of who ends up paying for all of it as AI keeps eating power. We dig into these on the Byte Bungalow channel, the same way I did here: reading the boring documents so you don't have to, and saying out loud where the numbers stop making sense.

If that's your kind of curiosity, come watch the video this one grew out of, and subscribe on YouTube so the next rabbit hole finds you.

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