5 ms·

This reminds me of SL-1, an experimental reactor that was meant to be used in the arctic circle. Part of the operation of the reactor required manually lifting

This reminds me of SL-1, an experimental reactor that was meant to be used in the arctic circle. Part of the operation of the reactor required manually lifting a control rod a few inches out of the reactor. However, possibly just to see what would happen or as a suicide attempt, they removed the rod too far and the reactor immediately exploded and killed 3 operators. At least, those are some intriguing theories about why the control rod was removed too far, but in fairness we really don't know what they were thinking and it may have simply been a mistake. Although a properly trained operator mistakenly lifting a heavy control rod too far begs more explanation. Whatever the case, it is an intriguing story. https://en.wikipedia.org/wiki/SL-1 https://en.wikipedia.org/wiki/SL-1 https://www.amazon.com/Atomic-Accidents-Meltdowns-Disasters-Mountains/dp/1605986801 https://www.amazon.com/Atomic-Accidents-Meltdowns-Disasters-...

TeMPOraL 5y ago
Between this and some other stories from early nuclear age, it makes me feel as if that system was designed by software engineers. If it's known that the control rod is supposed to be between 0 and X inches out, and going past Y inches (Y > X) will likely cause a fatal failure, one would expect someone to machine a piece of metal that makes in impossible to move the rod further out than Y inches. I read those accounts of people manipulating nuclear reactors by hand, and can't stop but think: this is dumb, even for 1950s era technology.
- leoc 5y ago
  > it makes me feel as if that system was designed by software engineers SL-1 feels as if it was designed and operated by Kerbals. TFA actually does mention the reactor and the accident > SL-1, a stationary low-power nuclear reactor in Idaho, blew up during refueling, killing three men. but that barely hints at just how eye-widening the whole saga was: https://www.youtube.com/watch?v=qOt7xDKxmCM https://www.youtube.com/watch?v=qOt7xDKxmCM To be fair, it is apparently considered likely that the overextraction of the rod was a deliberate murder-suicide. But yes, it seems that there's a reason that the US Navy still has a nuclear power program and the Army doesn't ( https://www.historynet.com/going-nuclear-idaho-falls.htm https://www.historynet.com/going-nuclear-idaho-falls.htm seems good; I am not an expert).
  - HPsquared 5y ago
    There was a lot of time pressure in those days of the Cold War. The other side was also working rapidly without much concern for safety. It was probably a consciously-made balance of risk, with relatively "minor" accidents here and there as a result of rushed development vs. the risks associated with getting overtaken by the Soviets. Technological superiority, particularly in that field, was a major factor in the balance of power at that time.
- Buttons840 5y ago
  That manually operated control rod was sophisticated compared to some of the earlier experiments. They used to stack bricks around a chunk of uranium, so the bricks would reflect neutrons back at the uranium. Eventually, once you stack enough bricks around the uranium it goes super critical and just goes nuts. They used to manually search out this super critical threshold by manually stacking bricks and then slowly move that final brick towards and away from the uranium and watch it balance on the line between sub critical and super critical. One day, someone dropped the brick and there was a blue flash. Lots of neutrons were released that day. People died from radiation exposure soon after. There's also a story about a fuel rod getting jammed, so they tried to force it with a crane and ended up breaking it in half, spilling highly radioactive water all over the place, and then the fuel rod catches on fire because it's not being cooled anymore. It's comical how quickly these disasters escalate. Read https://www.amazon.com/Atomic-Accidents-Meltdowns-Disasters-Mountains/dp/1605986801 https://www.amazon.com/Atomic-Accidents-Meltdowns-Disasters-... , it's accurate and relatively fun given the subject. One of the chapters is titled "The US Government almost never lost nuclear weapons", which I find subtly amusing.
  - joncrane 5y ago
    What about the "demon core?" It was a core of highly radioactive material, and instead of bricks, there were two hollowed out hemispheres made of some metal that reflected the radioactivity. Some guy put one hemisphere below the core, and had another one on top AND WAS USING A SCREWDRIVER to carefully titrate how "closed" the top hemisphere was to the bottom one. His hand slipped and he killed himself and some colleagues. Apparently the "demon core" got its name because it was involved in more than one supercritical accident.
    - Buttons840 5y ago
      I think the demon core was the "chunk of uranium" they were stacking bricks around. It's been several years since I read the book so my memory is fuzzy. I think the later experiments used the metal hemispheres instead of bricks.
      - 5y ago
- numpad0 5y ago
  Or safety education has improved far more than nuclear technologies did in the past 70 years.
acidburnNSA 5y ago
The SL-1 was part of the Army Nuclear Power Program, same as the reactors talked about in this post. [1] [1] https://whatisnuclear.com/reactor_history.html#the-army-nuclear-power-program https://whatisnuclear.com/reactor_history.html#the-army-nucl...
EamonnMR 5y ago
The "rod got stuck, they pulled too hard to free it" explanation fits very well with the known facts. The rush to blame the operators may have been due to a bias to protect the project.

TeMPOraL 5y ago

Between this and some other stories from early nuclear age, it makes me feel as if that system was designed by software engineers. If it's known that the control rod is supposed to be between 0 and X inches out, and going past Y inches (Y > X) will likely cause a fatal failure, one would expect someone to machine a piece of metal that makes in impossible to move the rod further out than Y inches. I read those accounts of people manipulating nuclear reactors by hand, and can't stop but think: this is dumb, even for 1950s era technology.

leoc 5y ago
> it makes me feel as if that system was designed by software engineers SL-1 feels as if it was designed and operated by Kerbals. TFA actually does mention the reactor and the accident > SL-1, a stationary low-power nuclear reactor in Idaho, blew up during refueling, killing three men. but that barely hints at just how eye-widening the whole saga was: https://www.youtube.com/watch?v=qOt7xDKxmCM https://www.youtube.com/watch?v=qOt7xDKxmCM To be fair, it is apparently considered likely that the overextraction of the rod was a deliberate murder-suicide. But yes, it seems that there's a reason that the US Navy still has a nuclear power program and the Army doesn't ( https://www.historynet.com/going-nuclear-idaho-falls.htm https://www.historynet.com/going-nuclear-idaho-falls.htm seems good; I am not an expert).
- HPsquared 5y ago
  There was a lot of time pressure in those days of the Cold War. The other side was also working rapidly without much concern for safety. It was probably a consciously-made balance of risk, with relatively "minor" accidents here and there as a result of rushed development vs. the risks associated with getting overtaken by the Soviets. Technological superiority, particularly in that field, was a major factor in the balance of power at that time.
Buttons840 5y ago
That manually operated control rod was sophisticated compared to some of the earlier experiments. They used to stack bricks around a chunk of uranium, so the bricks would reflect neutrons back at the uranium. Eventually, once you stack enough bricks around the uranium it goes super critical and just goes nuts. They used to manually search out this super critical threshold by manually stacking bricks and then slowly move that final brick towards and away from the uranium and watch it balance on the line between sub critical and super critical. One day, someone dropped the brick and there was a blue flash. Lots of neutrons were released that day. People died from radiation exposure soon after. There's also a story about a fuel rod getting jammed, so they tried to force it with a crane and ended up breaking it in half, spilling highly radioactive water all over the place, and then the fuel rod catches on fire because it's not being cooled anymore. It's comical how quickly these disasters escalate. Read https://www.amazon.com/Atomic-Accidents-Meltdowns-Disasters-Mountains/dp/1605986801 https://www.amazon.com/Atomic-Accidents-Meltdowns-Disasters-... , it's accurate and relatively fun given the subject. One of the chapters is titled "The US Government almost never lost nuclear weapons", which I find subtly amusing.
- joncrane 5y ago
  What about the "demon core?" It was a core of highly radioactive material, and instead of bricks, there were two hollowed out hemispheres made of some metal that reflected the radioactivity. Some guy put one hemisphere below the core, and had another one on top AND WAS USING A SCREWDRIVER to carefully titrate how "closed" the top hemisphere was to the bottom one. His hand slipped and he killed himself and some colleagues. Apparently the "demon core" got its name because it was involved in more than one supercritical accident.
  - Buttons840 5y ago
    I think the demon core was the "chunk of uranium" they were stacking bricks around. It's been several years since I read the book so my memory is fuzzy. I think the later experiments used the metal hemispheres instead of bricks.
    - 5y ago
numpad0 5y ago
Or safety education has improved far more than nuclear technologies did in the past 70 years.

acidburnNSA 5y ago

The SL-1 was part of the Army Nuclear Power Program, same as the reactors talked about in this post. [1] [1] https://whatisnuclear.com/reactor_history.html#the-army-nuclear-power-program https://whatisnuclear.com/reactor_history.html#the-army-nucl...

EamonnMR 5y ago

The "rod got stuck, they pulled too hard to free it" explanation fits very well with the known facts. The rush to blame the operators may have been due to a bias to protect the project.