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The 'why I am not worried' article, edited by MIT nuclear scientists

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Re: The 'why I am not worried' article, edited by MIT nuclear scientists

#71

Post by timinman »

icarus_drowning wrote: post #65
adlep wrote: post #30

Earlier quoted context omitted.

Well, it is all in the original title. The author's conclusion of "Why I am not worried" was based on the facts listed in his article. However, given the gravity of the current situation at the power plant we can assume that even though the facts listed in the article were all correct the author has misinterpreted them and reached a conclusion that that is wrong. Edit: Think of it as a physic text homework problem. Y…

Again, I'd posit that given the facts available 3/12, it was the right conclusion .

It was never the right conclusion to believe this kind of energy can be indefinitely managed.

Re: The 'why I am not worried' article, edited by MIT nuclear scientists

#72

Post by VladRussian »

icarus_drowning wrote: post #7
RandyHelzerman wrote: post #4

Or how I learned to stop worrying and love category 6 nuclear disasters. This is typical MIT hubris. Nobody knew om march 12 what was happening, even the operators, and even now nobody knows how bad thing are or how bad things will get.

>This is typical MIT hubris. I am getting tired of asking this, but which facts are wrong in the revised article?

which facts are true? How would you know? What is your source of info? PR by government, or the PR by the plant operator?

I completely support the nuclear energy and i consider Chernobyls is just a cost of doing business. Yet all this hysteria - everything is ok! everything is doomed! Com'n, we lost 30km area in Chernobyl, we'll lose a few kilometers diameter zone in this case - again it is the low price for the progress - we lost much more land for the roads for cars, we've been killing a lot more of animals and people for other reasons. Relax, we're making progress.

Re: The 'why I am not worried' article, edited by MIT nuclear scientists

#73

Post by jellicle »

timr wrote: post #56
cperciva wrote: post #48

Earlier quoted context omitted.

Maybe the "wide concrete tray" will capture the waste. Maybe it won't. Maybe the laws of physics will change, but I'd be willing to bet that they won't. But in the meantime, you're hoping that there's not a secondary fire from the heat Concrete doesn't burn. or a steam explosion At the point when the nuclear fuel melts, all the water has boiled off 1000 degrees ago. or some other kind of explosion that flings radioac…

"Maybe the laws of physics will change, but I'd be willing to bet that they won't." There's absolutely nothing about the "laws of physics" that guarantees that this particular reactor design is going to be able to contain a full meltdown, because it's never happened before . Nobody knows. "Concrete doesn't burn." No one said it did. There's plenty of other stuff around that does burn readily, which is why the plant i…

It's a shame that cperciva's nonsense is being modded up.

> "Nuclear reactors don't hold enough fuel to form a critical mass."

Come on. Each reactor core holds over 100 tons of uranium, of which about 3-5 tons is U-235. Critical mass under perfect conditions is 50 kilograms. Conditions are not perfect for forming a critical mass, but you've got 100 times as much U-235 as is strictly necessary, and there is no fucking way of knowing what will happen when an entire reactor core melts and flows together, because no one has ever been stupid enough to try it. Chernobyl experienced a criticality event, and there is absolutely no guarantee that Fukushima will not.

Moreover, each reactor has a spent fuel pool with five times as much fuel in it as the reactor itself has. And no containment vessel. And no water being supplied. And when the water boils away from those pools, and that fuel melts and flows together...

Re: The 'why I am not worried' article, edited by MIT nuclear scientists

#74

Post by mironathetin »

kitsune_ wrote: post #50

This is BULLSHIT, the guy (Oehmen) is a mechanical engineer with a management focus. He worked at my alma mater (ETHZ). His field of experties is supply chain risk management. Look up his papers, he isn't a nuclear physicist. I'd say he's about as qualified to make a comment on the situation as I am. The "essay" by Oehmen was first published by a notorious nuclear lobbyist, Jason Morgan. Look at this: http://nuclearf…

kitsune_, wrong choice of words, IMHO!

The article is full of facts that make absolute sense and shed light on a large number of things that the news do not get right. My thanks to the author especially for a clear interpretation of the explosions. We need a clear head and should rely on facts in these situations. We also should not assume that nuclear reactors are not well constructed. I am sure they are. So it does not come as a surprise to me, that someone who knows the details is able to explain them in a way that it makes sense.

This does not excuse the fact that the reactors failed. This is a different story. But it helps to understand what really happens now. What the author did not stress is the fact that, as the Zircaloy structure may have failed, all subsequent pressure releases will be highly contaminated.

BTW, engineers are the ones who know best how safety is constructed, not scientists (I write this as someone who got his phd in atomic physics. So I am not an engineer).

Re: The 'why I am not worried' article, edited by MIT nuclear scientists

#75

Post by lurch_mojoff »

timinman wrote: post #70
adsr wrote: post #63

Earlier quoted context omitted.

Totally agree with this, it reminds me of impenetrable software and unsinkable ships.

Exactly, the bottom line is were playing with nuclear reactions and hoping everything goes as planned. It's arrogance.

As is every technological and scientific achievement humankind has ever reached and is relying upon. Replace nuclear reactions with, say, human flight and your statement remains just as valid. I don't see many people crying out for abolishment of planes, though.

Re: The 'why I am not worried' article, edited by MIT nuclear scientists

#76

Post by yummyfajitas »

timr wrote: post #56
cperciva wrote: post #48

Earlier quoted context omitted.

Maybe the "wide concrete tray" will capture the waste. Maybe it won't. Maybe the laws of physics will change, but I'd be willing to bet that they won't. But in the meantime, you're hoping that there's not a secondary fire from the heat Concrete doesn't burn. or a steam explosion At the point when the nuclear fuel melts, all the water has boiled off 1000 degrees ago. or some other kind of explosion that flings radioac…

"Maybe the laws of physics will change, but I'd be willing to bet that they won't." There's absolutely nothing about the "laws of physics" that guarantees that this particular reactor design is going to be able to contain a full meltdown, because it's never happened before . Nobody knows. "Concrete doesn't burn." No one said it did. There's plenty of other stuff around that does burn readily, which is why the plant i…

There's absolutely nothing about the "laws of physics" that guarantees that this particular reactor design is going to be able to contain a full meltdown, because it's never happened before. Nobody knows.

Physics isn't biology/medicine. The laws of physics are not discovered by running experiments to enumerate every possible combination or permutation of configurations.

You're assuming an intact core. Criticality is a function of density, shape and temperature, in addition to mass. Melt the fuel rods, and the guarantees of that nice, well-moderated behavior are off.

The optimal shape for criticality is a sphere - surface/volume is the key factor here. A wide, shallow puddle at the bottom of the containment chamber is the least dangerous shape.

Temperature affects things because higher density makes achieving criticality easier. I.e., the colder things get, the more likely criticality is to be achieved.

Re: The 'why I am not worried' article, edited by MIT nuclear scientists

#77

Post by varjag »

rimantas wrote: post #53
kitsune_ wrote: post #50

This is BULLSHIT, the guy (Oehmen) is a mechanical engineer with a management focus. He worked at my alma mater (ETHZ). His field of experties is supply chain risk management. Look up his papers, he isn't a nuclear physicist. I'd say he's about as qualified to make a comment on the situation as I am. The "essay" by Oehmen was first published by a notorious nuclear lobbyist, Jason Morgan. Look at this: http://nuclearf…

> In short: FUD by nuclear energy lobbyists. So mechanical engineer cannot possibly say anything truthful about nuclear energy? The fact still remains: nuclear energy is the safest and cleanest we have for now. So far we had what, three serious incidents with total number of causalities of 35, all in Chernobyl. Sure it affected much more people but still: the single incident at Sayano-Sushenskoye hydroelectric power…

> The fact still remains: nuclear energy is the safest and cleanest we have for now.

Burning natural gas is both cleaner is safer, and it is a power source for much of Europe. I wonder why all nuclear advocates always bring in coal into the comparison.

Re: The 'why I am not worried' article, edited by MIT nuclear scientists

#78

Post by sofuture »

cperciva wrote: post #48
timr wrote: post #36

Earlier quoted context omitted.

"All good engineering works on the principle of defence in depth." That line is as much a sound-bite at this point as anything you'll hear on cable television. Yes, good engineering has many levels of fall-backs and redundancies. But when you've reached the point that you've evacuated the last fifty people from your site because it's no longer safe for them to be there , then you've exhausted your defenses. There's n…

Maybe the "wide concrete tray" will capture the waste. Maybe it won't. Maybe the laws of physics will change, but I'd be willing to bet that they won't. But in the meantime, you're hoping that there's not a secondary fire from the heat Concrete doesn't burn. or a steam explosion At the point when the nuclear fuel melts, all the water has boiled off 1000 degrees ago. or some other kind of explosion that flings radioac…

Your argument would hold a lot more water if all the other things that 'couldn't possibly' go wrong hadn't already gone wrong.

Re: The 'why I am not worried' article, edited by MIT nuclear scientists

#79

Post by moe »

brazzy wrote: post #68
rimantas wrote: post #53

Earlier quoted context omitted.

> In short: FUD by nuclear energy lobbyists. So mechanical engineer cannot possibly say anything truthful about nuclear energy? The fact still remains: nuclear energy is the safest and cleanest we have for now. So far we had what, three serious incidents with total number of causalities of 35, all in Chernobyl. Sure it affected much more people but still: the single incident at Sayano-Sushenskoye hydroelectric power…

total number of causalities of 35, all in Chernobyl Wrong, according to http://en.wikipedia.org/wiki/Chernobyl_disaster - 31 dead from acute radiation poisoning within months - 216 non-cancer deaths until 1998 - Between 9,000 (official government report) and 60,000 (TORCH report) cancer deaths overall

60,000 (TORCH report) cancer deaths overall

Thanks for pointing that out one more time. I'm not an anti-nuclear zealot but I'm getting extremely tired of supposedly intelligent people citing the "35 deaths" bullshit-figure on HN in each japan-thread.

If there had been only 35 or 4000 deaths then Chernobyl would not be considered a catastrophic event up to this day. Instead it would be considered a testament to the safety of the technology.

I wonder if the part that these people have trouble wrapping their head around is the latency?

This is what happens during a nuclear accident: Nothing. At the very worst we may see a few hundred immediate deaths. Other than that, life goes on.

The real aftermath kicks in 10-20 years later, when people start developing cancer and birth defects. Different sources report different figures for Chernobyl, partly due to political bias, and partly because it's just really hard to track >600k people over such a long timeframe.

However, the estimates from most sources other than the IAEA and the russian government range in the tens of thousands - quite a long shot from "35".

Re: The 'why I am not worried' article, edited by MIT nuclear scientists

#80

Post by moe »

lurch_mojoff wrote: post #75
timinman wrote: post #70

Earlier quoted context omitted.

Exactly, the bottom line is were playing with nuclear reactions and hoping everything goes as planned. It's arrogance.

As is every technological and scientific achievement humankind has ever reached and is relying upon. Replace nuclear reactions with, say, human flight and your statement remains just as valid. I don't see many people crying out for abolishment of planes, though.

I don't see many people crying out for abolishment of planes, though.

I think there's a tiny difference between a plane falling out of the sky and a nuclear reactor melting down. I'm sure you can spot it, too, if you think long and hard.

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