In the mid-1970s, after several decades of setting off nuclear devices in the desert “for science,” a small group at Los Alamos asked a question that can only be described as magnificently unhinged:

What if we used nuclear bombs as boiler fuel?

Thus, was born Project PACER (circa 1974–1976), a late-era descendant of Project Plowshare and the U.S. “peaceful nuclear explosions” program. The idea was simple in the same way a chainsaw-powered canoe is simple.

You would drill a massive underground cavity—preferably in a salt formation for self-healing containment—line it with steel, and then periodically detonate small nuclear devices inside it. The explosions would heat the surrounding rock to extreme temperatures. Water would be injected, steam would be produced, turbines would spin, electricity would flow, civilization would be saved.

Lather. Rinse. Detonate again.

Design studies envisioned a steady cadence of explosions—monthly or even weekly—to keep the cavern hot enough for continuous power generation. Some versions used thermonuclear devices, later “economized” to smaller fission devices once someone noticed that vaporizing a city block every refueling cycle might complicate maintenance.

How far did it get?

Surprisingly far on paper.

Los Alamos produced serious engineering studies: cavity mechanics, heat transfer, radionuclide migration, steam chemistry, tritium management, turbine contamination, and cost models. This was not a cocktail-napkin sketch. It was a federally funded feasibility program with real technical depth.

What it did not get was any dedicated testing. PACER itself never progressed beyond analysis and conceptual design. The closest practical data came from earlier underground nuclear tests and Plowshare experiments, which unintentionally served as “prototype boilers” in all the wrong ways.

By the late 1970s, PACER was quietly euthanized.

Why?

Three reasons:

1. Economics: Nuclear power is expensive. Nuclear power fueled by nuclear weapons is… aggressively expensive… 100’s of BILLIONS expensive.

2. Politics & arms control: Operating a commercial power plant that requires a continuous supply of nuclear bombs is what diplomats call “a conversation starter.”

3. Operations & contamination: Running turbines on steam laced with bomb debris turns routine maintenance into a radiological scavenger hunt.

Project PACER joined the long list of ideas that were physically possible, technically fascinating, and socially radioactive.