Tucked away in the Simi Hills of Southern California, about 30 miles northwest of downtown Los Angeles, sits a patch of land that changed nuclear history forever. Most people driving by the Santa Susana Field Laboratory (SSFL) today just see dry brush and rocky outcroppings. But in the late 1950s, this was the bleeding edge of American energy. It was the site of the SRE Sodium Reactor Experiment 1957, a project that promised a future of cheap, efficient power but ended up becoming a cautionary tale that still fuels legal battles and environmental cleanup efforts decades later.
The SRE wasn't your average power plant. It was a "first of its kind" deal.
The goal? To see if we could use liquid sodium—rather than water—to cool a nuclear reactor. Sodium stays liquid at much higher temperatures without needing to be under immense pressure. On paper, it was brilliant. In practice, it got messy.
By July 1957, the SRE actually made history by becoming the first civilian nuclear power plant to feed electricity into a commercial grid. It powered the nearby city of Moorpark. For a moment, it looked like North American Aviation’s Atomics International division had cracked the code. But by 1959, things went south in a way that the public wouldn't fully understand for years.
Why the Sodium Reactor Experiment was a Big Deal
Back in the 1950s, the "Atoms for Peace" era was in full swing. Everyone wanted nuclear power to be "too cheap to meter." The SRE Sodium Reactor Experiment 1957 was the poster child for this ambition. Unlike the pressurized water reactors (PWRs) we mostly use today, which are basically giant tea kettles, the SRE used liquid sodium to transfer heat from the core to the steam generators.
Sodium is weird stuff.
It’s a metal, but it melts at about 208 degrees Fahrenheit. It’s also incredibly efficient at moving heat. However, it has a "slight" problem: it explodes if it touches water and catches fire if it touches air. This meant the engineering had to be perfect.
The reactor used graphite as a moderator to slow down neutrons. The fuel was slightly enriched uranium. The whole setup was designed to produce about 20 megawatts of thermal heat and 6.5 megawatts of electricity. For a tiny experimental rig, that was a lot of juice.
People often forget how experimental this really was. We weren't just building a plant; we were testing a hypothesis. Could a sodium-cooled, graphite-moderated system be the standard for the entire world?
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The 1959 Meltdown: What Went Wrong
If you look at the logs from July 1959, you'll see things started getting "twitchy." This is the part of the SRE Sodium Reactor Experiment 1957 timeline that history buffs and environmentalists obsess over.
During "Run 14," the operators noticed the reactor's temperature was jumping around. It wasn't behaving. They tried to fix it, but the temperatures kept spiking.
What happened? Basically, a Tetralin leak. Tetralin was an organic seal coolant used in the sodium pumps. It leaked into the primary sodium loop. When that Tetralin hit the hot sodium, it decomposed into a black, gunk-like carbon residue. This gunk clogged the narrow cooling channels between the fuel elements.
Think of it like a heart attack for a reactor.
Without coolant flowing, the fuel rods overheated. Fast. Out of the 43 fuel elements in the core, 13 of them actually melted or were severely damaged. This wasn't a "China Syndrome" explosion, but it was a partial meltdown. The radioactive gases—mostly Xenon-135 and Krypton-85—accumulated in the "hold-up" tanks.
Here is where it gets controversial.
To prevent the building from over-pressurizing, the staff had to vent these gases into the atmosphere. They did it in "controlled bursts." At the time, the Atomic Energy Commission (AEC) and Atomics International downplayed the severity. They said there was "no release of radioactive materials" to the public. It took years, and a lot of digging by researchers like those at UCLA and the Committee to Bridge the Gap, to challenge that narrative.
The Ghost of Santa Susana Today
You can't talk about the SRE Sodium Reactor Experiment 1957 without talking about the cleanup. Or the lack thereof.
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The SRE was officially decommissioned in 1981. They tore down the buildings. They hauled away the soil. They filled the hole with "clean" dirt. But the groundwater underneath the Santa Susana Field Lab is a different story.
Contaminants like Trichloroethylene (TCE) and various isotopes (Strontium-90, Cesium-137) have been found in the area. While the SRE wasn't the only source of contamination at the site—there were rocket engine tests and other smaller reactor accidents—it remains the most famous.
For the people living in nearby Simi Valley and Oak Park, this isn't just history. It's a health concern. There have been numerous studies, some conflicting, about cancer clusters in the region.
Some experts, like those from the Department of Energy (DOE), argue that the radiation released during the 1959 incident was minimal compared to natural background radiation. Others, including former workers and independent physicists, argue that the "controlled venting" was much more significant than the official records suggest.
It’s a classic case of "who do you trust?"
Lessons From the Sodium Experiment
We actually learned a lot from the SRE. Maybe not what we wanted to learn, but lessons nonetheless.
First, sodium is a beast to manage. The world didn't give up on it—look at the Monju reactor in Japan or the BN-800 in Russia—but the SRE proved that "small" leaks lead to "big" disasters.
Second, transparency matters. If the AEC had been upfront in 1959 about the fuel damage, the level of public distrust today might be lower. Instead, the secrecy of the Cold War era created a vacuum that was eventually filled by fear and litigation.
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Third, graphite and sodium are a tricky mix. If the graphite isn't sealed perfectly, the sodium can soak into it, causing it to swell and block flow. Engineering for these "edge cases" is what makes modern nuclear design so expensive.
Actionable Insights for History and Science Buffs
If you're looking to dig deeper into the SRE Sodium Reactor Experiment 1957, don't just take one person's word for it. The history is layered.
- Check the DOE's Digital Archive: They have scanned original logs from the 1950s. You can see the actual handwriting of the operators during the "Run 14" incident. It's chilling.
- Look at the Boeing Cleanup Reports: Boeing currently owns much of the site. Their technical reports on soil remediation offer a very different perspective than the activist groups. Compare them.
- Visit the Site (Virtually): You can't just walk onto the SSFL—it’s restricted and still being cleaned up—but drone footage and satellite imagery show the footprint of where the SRE stood. It's a "scar" on the landscape that hasn't fully healed.
- Study the "Fast Breeder" Connection: The SRE was a precursor to the Hallam Nuclear Power Facility in Nebraska. Studying what happened at Hallam (which also failed) helps put the SRE into a broader context of 1960s technological overreach.
The SRE wasn't a total failure. It proved we could generate electricity with liquid metal. But it also proved that we weren't quite ready for the consequences when that metal stopped moving.
Honestly, the story of the SRE Sodium Reactor Experiment 1957 is a reminder that being "first" comes with a price. Sometimes that price is paid in Megawatts, and sometimes it's paid in decades of environmental litigation.
Moving Forward
If you're researching this for a project or just out of curiosity, focus on the "gap" between 1959 and 1979. That twenty-year window is when the "official" story and the "real" story started to drift apart. Understanding that gap is the key to understanding the legacy of Santa Susana.
To get the full picture, look into the specific roles of the Atomic Energy Commission and how their dual role as both "promoter" and "regulator" of nuclear power created a massive conflict of interest during the SRE cleanup. This structural flaw in the government led to the eventually splitting of the AEC into the NRC and the DOE we know today.
Also, keep an eye on the current SB 990 legislation and the ongoing negotiations between the California Department of Toxic Substances Control (DTSC) and the federal government. The SRE might be gone, but the legal fight over its "dirt" is very much alive.