Third Blast At Japan's Fukushima Nuclear Plant 691
iamrmani was one of several people reporting updates on the Fukushima Nuclear plant that has been struggling following last Friday's disaster. A third explosion (Japanese) has been reported, along with
other earlier information. MSNBC has a story about similiar reactors in the US. We also ran into a story which predicts that there won't be significant radiation. But already Japan is facing rolling blackouts, electricity rationing, evacuating the area around the plant, and thousands dead already.
Journalism (Score:5, Informative)
Poorly constructed sentence that last one, insinuating the deaths are related to the nuclear plant.
correction (Score:5, Informative)
Is not the third explosion.
means number 3 which refers to the number 3 reactor in the plant.
Up to present there were 2 explosions in the plant and not 3.
Re:Journalism (Score:5, Informative)
Third blast? (Score:5, Informative)
As far as I can tell, TFAs are about the SECOND blast, which happened on reactor 3 of the plant. NHK has nothing about a third blast. Am I missing something? Was there a third explosion, on reactor 2?
Re:Meltdown? (Score:5, Informative)
A meltdown... into the bottom of the containment vessel.
Yes, it'll be a pain to tidy up, but it will be nothing like Three Mile Island.
Read http://bravenewclimate.com/2011/03/13/fukushima-simple-explanation/ [bravenewclimate.com]
Read this first (Score:5, Informative)
Before commenting, try and understand the design and facts
http://bravenewclimate.com/2011/03/13/fukushima-simple-explanation/ [bravenewclimate.com]
Re:Third blast? (Score:5, Informative)
There is no explosion. There will be one tomorrow though.
About 2 hours ago Tokyo Electric Co reported that they've decided to flood reactor #2 after its cooling died earlier during the day. It is not clear when and why it died. Anyway, since it died, flooding procedure was begun. However, they are so far failing to cover the whole active zone with water. TEPCO's official said that that is suggesting the reactor core has melted to some extent.
Just 10 minutes ago it was confirmed that water is flowing in slowly, and about half of the fuel is covered.
Re:Journalism (Score:3, Informative)
Well, there were more injured in the second blast, perhaps that is how they spin it. There is a powerful anti-nuclear lobby active at the moment.
Re:what (Score:5, Informative)
(theorizing, former nuclear control room operator here from a plant of the same style, GE Boiling Water Reactor, as the ones with the problem)
They've at a minimum lost coolant to relief valve operation after they lost cooling due to loss of offsite (and local emergency diesel) power. They possibly also have some pipe breaks within the drywell containment structure. The relief valve operation is a form of "zero power" cooling unto itself, but you need to make up for the lost coolant somehow.
Nearly all emergency procedures that have a chance of keeping the plant intact depend on power being available, without power, you have to resort to destructive methods (sea water pumped in via fire pumps for instance) to keep things cooled off. Note also, that the equipment that would normally reduce or eliminate hydrogen buildup (the apparent cause of the building explosions) also require power.
While the earthquake was the root cause, the seawater being able to reach and apparently shutdown the emergency diesel generators onsite is why the problems got MUCH larger than what could have been.
Re:Meltdown? (Score:5, Informative)
Also, I would be interested to know how much this thing could raise the temperature of the worlds oceans by, if at all.
You're a retard.
Re:Unfortunate (Score:1, Informative)
Solar and wind already cost less per KW than nuclear.
Does this mean we can end all those solar and wind subsidies, then?
Re:Third blast? (Score:5, Informative)
Re:Unfortunate (Score:4, Informative)
From even the most optimistic sources I've read, solar costs something along the lines of 3-4 times more than nuclear per KwH. Wind power is supposedly cheaper than solar (by about about half), but can't deliver a consistent supply and is *heavily* dependent on location and weather (i.e., it's only cheaper if you're in a pretty consistently windy location with favorable weather). That's what I meant by "not ready."
Re:Meltdown? (Score:5, Informative)
So many people think of "nuclear meltdown" as "nuclear explosion". Not the case. Meltdown is just that; Melting down of the fuel. Gravity dictates that this fluid fuel will go down, so meltdown is of very little concern to anyone except the reactor ops. Remember that reactor 5 at Chernobyl exploded because of their idiocy on several levels, not because of any fault with the plant (which would have functioned perfectly well if the operators had followed procedure correctly and vented the pressure vessel when required).
I say bravo to the Japanese. They've done very well throughout all of this. The deaths reported are a result of a 9.0 earthquake and linked tidal wave, not any nuclear incident, and that just goes to show how safe it is. Interesting factoid from the article; The reactors were designed to withstand an 8.3 Richter scale quake. As the Richter scale is logarithmic, they withstood a quake seven times their maximum. The only "Woops!" point was when they shipped in portable generators to replace the tsunami-swamped diesel backups... With the wrong plugs.
Seriously, read that article and turn off CNN / Fox. They're actually lying to you.
Re:Journalism (Score:5, Informative)
Sorry to dampen you optimism, but these reactors are going to be totally useless after this. The reactor vessel will almost certainly be beyond repair and it is central to the entire plant. Economically it would be easier to just build a newer design of plant.
This headline and summary are completely wrong! (Score:5, Informative)
I live in Japan and have been following this news all day. The info in the headline and summary about the the reactors is complete incorrect. As to what has actually been happening:
First, the linked article is from 7 hours ago and is referring to the second explosion at Fukushima Daiichi of Reactor #3. The current situation as of 8PM Japan time was that the cooling system of Reactor #2 finally died and they just recently started filling it with seawater like the other reactors. This reactor is likely to cause another hydrogen explosion like the other two failed reactors before it. Also like the other reactors, this one may have suffered from some partial melting of its fuel rods.
Secondly, the article implies that thousands have died as a result of the problems at the Fukushima reactors. THIS IS NOT THE CASE! There have been reports of non-serious injuries and VERY mild radiation contamination but nothing that warrants any kind of panic yet.
Slashdot editors, please rewrite or delete this article, it is just spreading misinformation!
Re:Radioactive releases Could Last Months (Score:5, Informative)
Yes, they could just drain off all the water completely (so no more steam generation and no risk of pressure build up) but it would totally wreck the core since it would melt into its concrete containment system, then you'd have a big, broken mess left over (although with all the radiation contained) that you'd have to clean up.
This way they are hoping the core is not totally wrecked (although it will definitely be damaged and require extensive repairs before being used again, if ever), so that it is easier to clean up and reprocess the fuel, with the problem that because you are pumping water in there (at less than required flow rate) it's boiling off quickly raising the pressure very high and cracking to H2 and O2, which just love to react very exothermically - causing those explosions we have seen when they vent this pressure out into the atmosphere.
The best case is that they keep doing what they're doing, and try to minimise the chance of H2 explosions, so that it will be easy to dismantle the core when it is cold. If they just let it melt there will be no more hydrogen explosions, but they'll have a molten mess of fuel and reactor parts spread out inside the concrete containment shield that will be considerably more annoying to clean up (but still completely safe from an external observer point of view - it;s designed to fail this way in the event of a full meltdown).
I think the problem is that everyone is equating "meltdown" to mean "will explode like Chernobyl", which is not what happened there - the Chernobyl explosion was a catastrophic steam explosion like a pressure cooker exploding. The core didn't melt down until after the explosion happened.
These "little" explosions we are seeing in Japan are because they are releasing the pressure in a controlled manner - if they just left it (and disabled the safety systems) then it could face a similar problem to Chernobyl, with the reactor being destroyed by a steam explosion, with the crucial difference that the core of this reactor is totally shielded (Chernobyl's RBMK reactors were too big to contain without it costing a ridiculous amount, so the building was the secondary containment structure - and it fell apart like tissue paper, as expected).
It's also slightly different in Japan - the reactor is "off" so the uranium fission reaction has stopped, and it's just residual heat and decay product heat to be dealt with, so it's a relatively slow and controllable heating. In Reactor 4 in Chernobyl, the fission reaction was very definitely running - but was poisoned due to neutron absorbing products (the core was running at much too low power), and when these were gone, and with the rods all the way out, the reactor spiked to a massive level which flashed all the water in there to steam almost instantly, which blew the lid off the top - just like throwing an aerosol can onto a fire, or shooting it with an air rifle. They had no time to relieve the pressure.
Re:Meltdown? (Score:5, Informative)
Thermally, though, almost totally irrelevant. The three reactors that are running into trouble are a 460MWe and two 760MWe units. In rough numbers, I think that such plants might manage efficiency in the ~25% range, which would correspond to total heat outputs of 1840MW and two at 3040MW(under optimal, full-power operating conditions). 1 calorie is the energy required to raise the temperature of 1gm of water by 1 degree celsius, 4.184 joules. If we go with our(pessimistic) assumption that the meltdown mass is putting out heat equivalent to the reactor operating as designed, that means 1840 million J/s or roughly 440,000,000 calories/s. That would mean that, per second, at maximum output, the core would be good for raising the temperature of 440,000L of water by 1 degree every second.
More plausibly(because there is no way that a meltdown blob is going to come in contact with that much water that fast), it will superheat the water immediately surrounding it, generating some very, very toasty steam(some of which will lose energy to the surrounding water, heating it, some of which will escape into the atmosphere). Thus, a fair percentage of the thermal energy will into the atmosphere, or into overcoming the enthalpy of vaporization of water, which is fairly high.
Even if 100% of the thermal energy from all three crippled reactors went directly into heating water (7920MW or ~1.9 billion calories/s) it would be facing the ~1.34442 x 10^21 L of water in earth's oceans. That would provide ~1.4x 10^-12 calories/s for each Liter. If we make the (highly pessimistic) assumption that the reactor meltdown blobs would continue at full power for a decade(315 569 260 seconds), that would correspond to a 0.000445977891 degree (celsius) rise in world ocean temps.
Spilling the fun stuff that you find in a live reactor is a terrible plan. Wholly ill advised. Don't do it. Not really a thermal concern, thon,
Re:What is the greatest enemy of nuclear power? (Score:4, Informative)
Third generation plants (the kind who's design is currently being held up in congress by idiocrats) use a passive emergency cooling system that circulates cooling water using natural convection, and it does not require electric pumps to function.
Re:Enough already? (Score:4, Informative)
Except quakes > 7.9 are not 1000 year events. There have been dozens in the last 50 years. At any given highly active location (like Japan) the chance of one in 50 years is pretty high.
Re:Enough already? (Score:4, Informative)
As an example, the two most vulnerable fission plants in the US are built for 7.0.
http://www.cbsnews.com/stories/2011/03/14/earlyshow/main20042815.shtml [cbsnews.com]
They're also near a large fault, and potentially subject to larger quakes.