Comment on rollin' coal
AngryCommieKender@lemmy.world 6 months agoThe part that I’m amazed by is that no civilian seems to know about the TVA meltdown. It’s the only full meltdown we ever had, and the Army Corps of Engineers lost all access to nuclear power because of that incident, as they intentionally melted it down to test China Syndrome. This was in the 50s. They did build the thing inside of a mountain to contain all the radiation, but had the physicist that came up with China Syndrome been right, that wouldn’t have really mattered. They also could have just done the math to figure out that, yet again, the physicist in question understood physics just fine, but lacked in mathematics.
i’ve never heard of it, i would assume it isn’t out there. Technically there is one other meltdown we had though, the SL-1 reactor, killed three people. Caused a bit of a mess, wasn’t super significant though.
Was that a naval/sub reactor? Or was this something else?
That was an Army test reactor. The Navy has a spotless record, so far.
ye, i was mostly mentioning it because it is technically another true meltdown of a reactor within the US.
Naval sub reactors i know have a spotless record, across the aisle, amusingly. Ship reactors i would imagine are less of a problem, though im guessing those are just stolen from subs so equally spotless most likely.
It is my understanding that the Three Mile Island incident was a meltdown, that the fuel rods got hot enough to melt themselves and pool in the bottom of the reactor vessel but did not escape containment, unlike Chernobyl whose reactor core is currently a big lump in a sub-basement.
TVA meltdown
Ok so TMI, is actually a cumulation of three primary factors, none of which should’ve happened.
The first was that they had bad/broken gauges and equipment that was hard to read, meaning they didn’t know the state of the reactor exactly like they should have been able to.
Second, they had the auxiliary cooling pumps shutdown for maintenance. Now normally this wouldn’t be a huge problem if you’re following procedure, as procedure dictates (this was also the law btw) that when your reactor core is running, the auxiliary cooling lines need to be active.
And third, the reactor core was operated under only the primary water feed lines. I.E. power generating feed water. Which as i said is not allowed.
Once they had a crew change, the new crew immediately realized everything had melted down, and called for shutdown. Only took like 8 hours or something.
Chernobyl was a little more complicated, because chernobyl wasn’t designed with a PCV (primary containment vessel), technically it had a secondary containment, which would be the building around it, but obviously that didn’t help. It was theorized and believed by the engineers (and the operators, ignoring a certain condition where this wouldn’t be true, which nobody knew about) that it was impossible for the plant to have a meltdown, primarily due to the fact that it was such a spread out core, making it react slower to immediate changes in the power production.
However, during the day when this happened, (i wont go into all the detail because i will be here for hours otherwise.) the plant was in a xenon well, meaning that it was able to produce virtually zero fission (xenon absorbs neutrons) and the operators didn’t realize it, so they pulled out nearly all of the control rods trying to bring it back up (for a loss of power test) only to then have all the xenon start decaying at about that period of time, which meant the power level started to aggressively increase, and since there were no control rods, it sort of hit a runaway condition. Leading to the entire plant fucking exploding, due to a steam explosion specifically. This one was a lot more like a steam boiler explosion in a locomotive than a nuclear explosion or even hydrogen explosion (though that could’ve been the second explosion that happened)
Chernobyl is a big lump in a sub basement, but that was still the result of a chemical explosion, not a meltdown. My point was that the only meltdown incidents have been caused by the US.
TMI is a bit of a sticky wicket, because as you say the roda did melt, but we got it back under control before abything more than some steam escaped containment.
so technically, it wasn’t a chemical explosion at chernobyl, it was a steam explosion, followed by a possible hydrogen explosion, though that would have been due to chemical reactions ultimately iirc.
Also technically, chernobyl is a meltdown incident, meltdown is described as “severe core damage” And considering that core no 4 no longer fucking exists, i think it’s fair to call it a meltdown incident.
You can have severe core damage without any nuclear reactions. A meltdown is severe core damage caused by a nuclear reaction that got out of control.
There aren’t “steam explosions” in physics. There are chemical reactions that cause an explosion, pressure buildups that cause an explosion, and nuclear explosions.
The steam was a pressure buildup that caused the incident resulting in an initial pressure explosion. The thing that “melted” the core of Chernobyl was the hydrogen exploding, hence a chemical explosion. Had it been a nuclear event that melted that core, neither Kiev nor Moscow would be inhabitable. The capital of Russia would be St. Petersburg, and Ukraine wouldn’t exist, as well as several other Soviet Oblasts in the area.
What do you think a “meltdown” is?
When the melted bit, caused by an uncontrolled nuclear reaction, escapes containment.
Emerald@lemmy.world 6 months ago
I looked up TVA meltdown, got no results about it.
AngryCommieKender@lemmy.world 6 months ago
It may still be classified. I learned about it in Nuclear Power School in the Navy