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Japan and the Nuclear situation

byteware said:
At the moment, that isn't so clear to the people dealing with the situation (unless that situation has been updated since I arrived at work this morning).
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Can this end up like Chernobyl?

No, it cannot. for several reasons.

Chernobyl used graphite as a neutron moderator and water as a coolant. For complicated reasons, this meant that as the coolant heated up and converted to steam, the fission reaction intensified, converting even more water to steam, leading to a feedback effect. The Fukushima reactors use water as both the coolant and the neutron moderator, which means that as the water heats up and converts to steam, the reaction slows down instead. (The effect of the conversion of water coolant to steam on the performance of a nuclear reactor is known as the "void coefficient", and can be either positive or negative.)

Chernobyl was designed so that as the nuclear fuel heated up, the fission reaction intensified, heating the core even further, causing another feedback effect. In the Fukushima reactors, the fission reaction slows down as the fuel heats up. (The effect of heating of the nuclear fuel on the performance of a nuclear reactor is known as the "temperature coefficient", and can also be positive or negative.)

Chernobyl's graphite moderator was flammable, and when the reactor exploded, the radioactive graphite burned and ended up in the atmosphere. The Fukushima reactors use water as a neutron moderator, which is obviously not flammable.
 
shadowninty said:


Can this end up like Chernobyl?

No, it cannot. for several reasons.

Chernobyl used graphite as a neutron moderator and water as a coolant. For complicated reasons, this meant that as the coolant heated up and converted to steam, the fission reaction intensified, converting even more water to steam, leading to a feedback effect. The Fukushima reactors use water as both the coolant and the neutron moderator, which means that as the water heats up and converts to steam, the reaction slows down instead. (The effect of the conversion of water coolant to steam on the performance of a nuclear reactor is known as the "void coefficient", and can be either positive or negative.)

Chernobyl was designed so that as the nuclear fuel heated up, the fission reaction intensified, heating the core even further, causing another feedback effect. In the Fukushima reactors, the fission reaction slows down as the fuel heats up. (The effect of heating of the nuclear fuel on the performance of a nuclear reactor is known as the "temperature coefficient", and can also be positive or negative.)

Chernobyl's graphite moderator was flammable, and when the reactor exploded, the radioactive graphite burned and ended up in the atmosphere. The Fukushima reactors use water as a neutron moderator, which is obviously not flammable.
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What you are missing shadow, is that all this means is that it won't be the same PROCESS as the one in Chernobyl. Since we've already had two explosions inside reactors... there is a very VERY real risk of a serious radiation leak.
 
bigbadwulff said:
Chernobyl: One more reason not to let any country "go authoritarian". No checks and balances, only corruption.
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FTFY
byteware said:
What you are missing shadow, is that all this means is that it won't be the same PROCESS as the one in Chernobyl. Since we've already had two explosions inside reactors... there is a very VERY real risk of a serious radiation leak.
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sure, but the prospect of a Chernobyl style spewing of radioactive particles into the atmosphere is not really possible
 
shadowninty said:
no.
there are venting mildly radioactive steam (hydrogen was too iirc)
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They are currently venting radioactive steam from the internal chamber, to the outside casing. However, as the explosions continue, the outside casing may not hold.

No radioactive material has been released into the environment, that I am aware of.



Ken Bergeron - Physicist said:
What's happening in Japan is called a station blackout, physicist Ken Bergeron tells Scientific American. That happens when both external power lines and emergency power at the site fail, and it's exceptionally rare. The worst that could happen, Bergeron says, is that water drops below the fuel-containing uranium rods, causing them to heat up, burst, and release nuclear byproducts. That could cause the core to melt, and potentially the reactor vessel as well. "It's likely to spread as a molten pool
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Jeepers i feel so sorry for those poor Japanese people,

But since we are talking about Chernobyl then why has not ONE single person included how South Africa's (and Africa's) only nuclear power station (Koeberg) almost went Nuclear meltdown and could have killed millions in South Africa because our government puts useless and inept crack heads in charge of a once very important Nuclear Power plant in Cape Town...

Here:

Koeberg Reactor Near Meltdown no cause for concern! Medialternatives

Koeberg Nuclear Power Station - Wikipedia, the free encyclopedia

Why has nobody mentioned how important this single event really is?
 
shadowninty said:
because these things are not that unusual in middle income countries, it was not a meltdown, and its irrelevant
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Nope shadow sorry you have no idea what you are talking about...

It could have very well gone wrong but nobody else came to help us... nobody cares about us thats why we got no help

There should be laws against countries that have nuclear power stations to make sure they put the right people in the right place but in Japan's instance with the natural disaster that is a different...

All I am trying to say which you misunderstood shadowninty is why did the world not help us as well do you see what i am getting at?

You have not a single clue as to what I am talking about.
 
Stinky Stinky said:
Nope shadow sorry you have no idea what you are talking about...

It could have very well gone wrong but nobody else came to help us... nobody cares about us thats why we got no help

There should be laws against countries that have nuclear power stations to make sure they put the right people in the right place but in Japan's instance with the natural disaster that is a different...

All I am trying to say which you misunderstood shadowninty is why did the world not help us as well do you see what i am getting at?

You have not a single clue as to what I am talking about.
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if you had a partial meltdown im sure countries would be rushing to your aid
 
I would just like to point out that water, under these conditions is very flammable. Where do you think the hydrogen is coming from.

2 H2O → 2 H2 + O2; E0=3798.20 kJ

The core has to be above 3798.20 kJ= ~2000C to get water to thermal decompose into hydrogen and oxygen. Now 2000C is a funny number because that is the same melting point as the nuclear pellets. Which by definition is a meltdown.

The only other way is if electricity is being applied to water,

2 H2O(l) → 2 H2(g) + O2(g); E0 = +1.229 V

But that would require a breach between the electrical system and water. Which means that the power plant would just short out.

Just wanted to point this out.
 
its generally believed that a partial meltdown occurred in some of the three reactors if not all
due to be shutdown in May anyway
 
RiverOfIce said:
I would just like to point out that water, under these conditions is very flammable. Where do you think the hydrogen is coming from.

2 H2O → 2 H2 + O2; E0=3798.20 kJ

The core has to be above 3798.20 kJ= ~2000C to get water to thermal decompose into hydrogen and oxygen. Now 2000C is a funny number because that is the same melting point as the nuclear pellets. Which by definition is a meltdown.

The only other way is if electricity is being applied to water,

2 H2O(l) → 2 H2(g) + O2(g); E0 = +1.229 V

But that would require a breach between the electrical system and water. Which means that the power plant would just short out.

Just wanted to point this out.
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No. The hydrogen comes from the exposed zirconium cladding being burned off the fuel bundles (oxidation), creating pockets of H2 that need to be vented.
 
Why did Japan install a nuclear reactor when they know they are susceptible to such epic natural disasters including earthquakes and tsunamis?
 
byteware said:
What you are missing shadow, is that all this means is that it won't be the same PROCESS as the one in Chernobyl. Since we've already had two explosions inside reactors... there is a very VERY real risk of a serious radiation leak.
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There have been no explosions inside the reactors, explosions inside the containment buildings yes, but that is exactly what they were designed for. They exploded off the hydrogen gas that had built up in the building, in the cases of reactors 1 and 3 it still appears the containment vessels have held up. In reactor 2's case it appears that the containment vessel may have cracked.

For the record, there is a monumentally LARGE difference between the reactor vessel exploding, and the containment building exploding. Please try and get it right in these cases.
 
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