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Happy Birthday, Nuclear Power

"A possibly catastrophic experiment in one of the most densely populated areas of the nation!"
​Image: Argonne National Laboratory

​On Dec. 20, 1951, the first trickle of electricity seeped from the EBR-1 turbine generator, a nuclear "breeder" reactor brought to life by nuclear physicist and Manhattan Project figure Walter Zinn. Housed at a high-desert desert facility (now known as Idaho National Laboratory) not far from Craters of the Moon National Monument, the generator featured a core about the size of a football and output enough to power its own building, but not much more.

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EBR-1, known also as Chicago Pile 4 (CP-4) and Zinn's Infernal Pile ("pile" referring to the stack of graphite blocks and uranium pellets making up the reactor), was one of ​a succession of reactors developed through the 1940s and 50s, originally as a direct extension of the Manhattan Project. CP-1, which demonstrated the first critical or self-sustaining nuclear reaction in 1942, CP-2, and CP-3 were all located in and around Chicago, including one site located under some bleachers at the University of Chicago.

The procession of reactor piles were all treading in uncharted territory. On paper, the reactions would remain controlled, but, you know, unexpected shit happens. Like a nuclear explosion. Of the CP-1 test, featuring a completely unshielded and uncooled reactor, a historian at the US Atomic Energy Commision ​would later remark, "a possibly catastrophic experiment in one of the most densely populated areas of the nation!"

CP-4 was to be the nuclear bridge, proof that this entirely bizarre realm of physics could power light bulbs and radios and vacuum cleaners. Work on Zinn's Infernal Pile started in 1949, with the result being yet another new variation on nuclear power generation. As a breeder reactor, it would be capable of generating its own fuel (sort of); that is, it would create more fissile material than it consumed, offering an even greater fuel economy than "normal" fission. (Note that the technology hasn't really taken off, even given a further half-century of research.)

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The reactor itself was a burrito of sorts, made of an 8-inch cylinder wrapped in a 4-inch thick blanket of uranium. This was the inner vessel and it was cooled by a mercury-like liquid metal (guacamole, if you will). Outside of this was another, even thicker layer of uranium. The relatively large amount of "fertile" uranium tightly packed around the core is what made it a breeder, as the reaction would burn through this material to make a bunch of bonus plutonium.

Image: Argonne National Laboratory

The first bit of electricity was used to power a mere four light-bulbs, while the next day it powered the entire building. (It was rated for 300 kilowatts of output, e.g. just enough.)

The reactor's history is recounted in a ​2001 interview with Leonard Koch, the EBR-1 project's assistant director. It was first published in Nuclear News.

"It was just another regular day for all of us," Koch recalled. "We all assembled for the test, the reactor and heat transfer systems were made operational, Harold Lichtenberger turned a switch, and the light bulbs that had been strung had lit up. That was it. This was what we worked toward for several years."

So it goes. "This was what we expected to happen," Koch said. "When something like that occurs, sometimes it's difficult to attach much significance to it. For example, I remember reading a book about the early days of the airplane business. When Orville and Wilbur Wright flew that airplane the first day, they didn't do anything great. They didn't even crack open a bottle of champagne."

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Two years later, EBR-1 suffered a partial meltdown. It occurred during one of several experiments designed to help the physicists understand a certain anomaly, a "positive power coefficient." The rods within the core were bending inward as the result of the extreme thermal imbalance between the inner and outer portions (read: things expanding and contracting). This meant losing some control over the reactor.

"All of the available ideas for investigating the phenomena seemed to involve high risk," wrote Ray Haroldsen, an EBR-1 project team member, in ​a short history of the event. "Since the reactor was essentially at the end of life, this seemed to be the time when higher than normal risk would be acceptable. A plan was developed and the AEC was notified of the intent to conduct this high risk experiment."

"Later, when the experiment resulted in the meltdown, the AEC denied that they knew anything about it," Haroldsen added.

The meltdown was halted quickly, but enough radioactive gas seeped out to call for the evacuation of the building. It was four months before they could get back in and inspect the damage. This was mostly due to the AEC's unwillingness to vent the collected gas for fear of disturbing the large array of new detection instruments designed to register nuclear weapons testing in the Soviet Union. It was the Cold War and all.

Not long afterwards, the EBR-1 project became overshadowed by the new neighboring Borax reactor, which famously had begun powering the town of Arco, Idaho. The project continued, however, until a 1964 decommissioning. It's now a publicly-accessible historic site.