[Fukushima, power stations, nuclear scare]

[geonuc]

One thing that really cheesed me off in the coverage; an independent nuclear consultant complained that people always overstate the symptoms of radiation poisoning, which leads to authority figures understating the risks, to avoid mass panic. Now I may be a superstitious prole, but from what I've read of the symptoms of acute radiation sickness, I'd sooner get Ebola. So are the public wrong to view radiation sickness as a fate worse than death?

Acute radiation sickness occurs with doses much higher than any member of the public will absorb in this incident, or the one at Three Mile Island, or Chernobyl. Some workers and involuntary draftees at Chernobyl died from acute radiation sickness.

But yes, it is a horrible way to die, in my opinion.

[Ara Pacis]

According to the BBC (quoted in the Wikipedia article), one of the civilian evacuees (patients at the hospital) who were checked for radiation showed 45nCi (nanocuries) and two more showed 18nCi and 14nCi. According to the article, that is enough to require decontamination.

[geonuc]

According to the BBC (quoted in the Wikipedia article), one of the civilian evacuees (patients at the hospital) who were checked for radiation showed 45nCi (nanocuries) and two more showed 18nCi and 14nCi. According to the article, that is enough to require decontamination.

It might be, but those are very small amounts of radioactive material.

[aar14]

Do you guys think the reactors will melt down?

[HenrikOlsen]

WWN lists the exposures in the unit actually used for measuring exposure by anyone in health physics, and they list one worker who got an immediate radiation dose as receiving 106 mSv (millisievert) which is considered within the limits of what's acceptable in emergencies.
It's about 1/10th of the level that causes nausea and about 1/30th of LD50.

Curie is used to indicate contamination, measured in number of radioactive decays per second (1 Ci = 3.7×10¹⁰ decays per second). To give an indication of how little 45 nCi really is, it is only about 10 times the Radon-222 an average domestic home has per cubic yard, less than half (about 100 nCi) of the potassium-40 an average human body has and about 1/22 of what a domestic smoke alarm has.
For that matter, it's also about 1/22nd of the amount of carbon-14 ingested for diagnostic purposes in the medical urea breath test.

[geonuc]

Do you guys think the reactors will melt down?

I think there is likely to be damage to the Unit 1 reactor core, but if by meltdown, you mean significant melting of the core as in what happened at Three Mile Island, I don't think so.

[aar14]

I think there is likely to be damage to the Unit 1 reactor core, but if by meltdown, you mean significant melting of the core as in what happened at Three Mile Island, I don't think so.

I just see articles like this popping up, saying:

A meltdown may be occurring at one of the reactors at a damaged nuclear power plant in northeast Japan, a government official said Sunday morning, sparking fears of a widespread release of radioactive material at a time when rescuers are frantically scrambling to find survivors from the country's strongest-ever earthquake.

And Yahoo! says there's threat of a nuclear meltdown, just gets a bit scary at times but I guess that's what you get from the news?

I also made another post here, and still looking for answers, thoughts? And thanks.

[HenrikOlsen]

And even if there is melting, that type of reactor is built so any melt off from the reactor would drain down through channels made specifically for that eventuality and spread out into a torus shaped channel which has the effect of getting it far below criticality even without a neutron poison.

[SkepticJ]

Is the "news" going to report on that, though? That it simply isn't possible for it to turn into another TMI or Chernobyl? Don't count on it.

Whip up the fear, that's what sells.

I fear all this is going to gravely damage public acceptance of nuclear energy, below where it already is; which is the exact opposite of what needs to happen at this point in history--fossil fuels completely running out in maybe a century, and all the global warming that's going to happen.

At least Japan is 30% powered by nuclear energy already, if the West goes under post-fossil fuels due to our short sightedness, they'll keep high-tech civilization going.

[aar14]

Interesting. Thanks for the replies guys

Also, I just got an update from CNN on my phone that they "assume meltdown has occurred" with that said, do you think there is any possibility that this could affect the North America or Hawaii?

Sorry for not providing a link as I'm posting from my phone.

[danscope]

And just how does cesium get released in an event? Melting fuel rods. Come now, be honest. That pile was uncovered .
Not good.
I'm hoping that the prevailing wind will be from the NNWest and stay there.

[HenrikOlsen]

You're forgetting (or don't know) that the predecessor of Cesium-135 is Xenon-135, an inert gas which in the high neutron-flux environment of a running reactor is mostly often transmuted through neutron absorption to Xenon-136 which is stable, but when the reactor is stopped through the insertion of control (and possibly SCRAM) rods, that flux goes away and the Xenon-135 will instead decay (half-life 9.2h) to Cesium-135 which is a much slower process, while still being produced from Iodine-135 (half-life 6.57h) so the Xenon-135 concentration actually rises for the first about 11 hours after the reactor was shut down, dropping after the Iodine-135 levels starts to drop so much that new production becomes less than decay. This also means that Cesium-135 generation is a fairly distinct symptom of reactor shut-down.

As an inert gas, Xenon-135 (like the other Xenon isotopes) is perfectly capable getting out of the rods without them melting and then further out when venting due to overpressure, out in the containment building where the Cesium is then produced.
The Cesium isn't a sign of exposed and melted fuel rods, it's an expected sign of venting of a recently shut down reactor.

[Scriitor]

A possible meltdown at a second reactor is now being reported.

[aar14]

A possible meltdown at a second reactor is now being reported.

Are these of any threat to North America?

[Van Rijn]

I also made another post here, and still looking for answers, thoughts? And thanks.

Their claim is nonsense. People forget, or just don't realize, that there used to be atmospheric nuclear weapons tests which distributed radioactive material far more effectively than this ever could.

[aar14]

Thanks for setting my mind at ease Van Rijn, I believe that map was a fake created over at 4chan.org.

What does this mean for the people in Japan?

[HenrikOlsen]

Are you trying to say that this would be the second reactor to melt down (there isn't really any indication at the moment that Fukushima Daiichi 1 has done so) or the second reactor where there's a risk that it can melt down?

http://www.world-nuclear-news.org/RS...3_1303111.html

Now Tepco has reported it has not been able to restart unit 3's high pressure injection system after an automatic stop. This has left the reactor without sufficient coolant and obligated Tepco to notify government of an emergency situation.

Preparations for potential pressure relief had already been underway for many hours. Noriyuki Shikata, director of global communications in the prime minister's office, said the operation was expected to cool the containment, noting that "minute quantities of radioactive materials are released." When this occurred at unit 1, the International Atomic Energy Agency said the emission would be filtered to retain radioactive materials within the containment.

A ten kilometre evacuation order is in effect and some 200,000 people have been moved from their homes so far.

Incidentally, WNN now says that the explosion at Daiichi 1 was a hydrogen explosion as initially suggested.

[Scriitor]

A second reactor where a meltdown may already be occurring, according to various mainstream media accounts.

http://www.theglobeandmail.com/news/...rticle1939779/

http://www.k5thehometeam.com/Global/...asp?S=14241459

http://www.abc.net.au/news/stories/2...13/3162752.htm

[Van Rijn]

Is the "news" going to report on that, though? That it simply isn't possible for it to turn into another TMI or Chernobyl? Don't count on it.

And of those two, only Chernobyl had a major release of radioactive material, so another TMI is a happy outcome, aside from cost.

[RGClark]

If the main problem is just getting enough portable power there then there are portable gas turbine generators capable of putting out 10's of megawatts. You could also use the power from a nuclear aircraft carrier at a power range of 200 megawatts, though there might concern about bringing it off shore in a zone subject to tsunamis.

Nuclear powered submarines would provide another means of providing portable power for the reactor cooling systems. The American Seawolf submarine uses 40 megawatt reactors and the Russian Akula class submarines operate at 190 megawatts.
There would be less concern for tsunamis for submarines if operated off shore. You would still likely need to be hundreds of yards off shore for their required depth to operate. Then you would also need sufficient cabling to cover that distance.


Bob Clark

[Ara Pacis]

Nuclear powered submarines would provide another means of providing portable power for the reactor cooling systems. The American Seawolf submarine uses 40 megawatt reactors and the Russian Akula class submarines operate at 190 megawatts.
There would be less concern for tsunamis for submarines if operated off shore. You would still likely need to be hundreds of yards off shore for their required depth to operate. Then you would also need sufficient cabling to cover that distance.

You'd need to be farther out that a few hundred yards, more like several miles depending on bathymetry. In the event of a large tsunami, a lot of that water is going to end up inland, taking the vessel with it. Submarines won't be any better off than surface vessels WRT a tsunami out at sea where the amplitude is small. Submarines might be better WRT storm waves, since those waves are surface action, but a tsunami moves the entire water column from the bottom of the ocean to the surface.

[Jens]

And even if there is melting, that type of reactor is built so any melt off from the reactor would drain down through channels made specifically for that eventuality and spread out into a torus shaped channel which has the effect of getting it far below criticality even without a neutron poison.

Thanks, that's nice to hear. It's true that media hasn't reported that at all. But to be fair, it isn't really all their fault. The government agency has press conferences but keep saying they don't know what's happening, and the media have experts on but the experts say they're not sure what's going on either. So the media doesn't have much of a choice but to speculate.

With regard to the question of what this could mean for the people of Japan, the actual accident itself doesn't pose much danger for the public. I think it's more an economic and electric power issue. I assume that the reactors will be offline for a long time, if not permanently, and it will become that much harder to build new plants.

[Procyan]

Some news reports say that they are using seawater as emergency coolant. The salt water is corrosive and one interpretation was that they had decided to scrap the 40 year old plant(s).

But if they hose it down, won't the seawater carry radioactivity into the environment???

[slang]

Thanks, that's nice to hear. It's true that media hasn't reported that at all. But to be fair, it isn't really all their fault. The government agency has press conferences but keep saying they don't know what's happening, and the media have experts on but the experts say they're not sure what's going on either. So the media doesn't have much of a choice but to speculate.

I don't know about that, Jens. The Weekly Nuclear News seems to do pretty well, reporting factual and without sensationalism. Where the media get it wrong is where they start to yap around the actual issues. Anchormen somehow seem to need to run their mouth all the time, and you can actually see the misreporting any time they interview an expert. The expert will make some statement, the anchor will "helpfully" interpret that, and to make it easier for the public leave out any of the qualifying statement the expert made, with the anchor always interpreting at least one thing wrong. Then some editor strips even that down, and we get panicky headlines.

With regard to the question of what this could mean for the people of Japan, the actual accident itself doesn't pose much danger for the public. I think it's more an economic and electric power issue. I assume that the reactors will be offline for a long time, if not permanently, and it will become that much harder to build new plants.

I agree. I don't know how much of a dent this will be in Japan's total energy production, but I'm sure it won't help in the days ahead. On the other hand, there will be lots of lessons learned from this, and nuclear power will become safer still.

[Strange]

Thanks, that's nice to hear. It's true that media hasn't reported that at all. But to be fair, it isn't really all their fault. The government agency has press conferences but keep saying they don't know what's happening, and the media have experts on but the experts say they're not sure what's going on either. So the media doesn't have much of a choice but to speculate.

The BBC had another expert (or do I mean "expert") on this morning stating with certainty that there had been a meltdown at reactor 1 and possibly 3, that containment had been breached (he may have said destroyed) and the only reason they had flooded the reactor with seawater was to prevent the melted fuel being exposed to the air. I would have been happier if he had (also?) given Henrik's explanation above regarding what happens to any melted material. I'm not sure why covering the material with sea water at that point would help. If anything, presumably some of the components are (chemically) reactive, so could make things worse.

[Glom]

Unit 1 was supposed to be decommissioned soon anyway so I don't think it's loss is a problem. The fact that all the others are damages will be.

I'm really annoyed about this. We've had the media and the usual suspects running amok billing this as a new Chernobyl scaring people to death and all on false pretenses. The daily mail, the rag that brought you the anti GM hysteria and MMR scare, has been going full throttle on it.

This isn't a Chernobyl. This is maybe a TMI, aka a panic attack. And all of it was caused by one of the earthquakes ever recorded and even that couldn't cause nuclear Armageddon from a 40 year old unit. Far from raising questions about the safety of nuclear power, it is the best demonstration of it.

[jlhredshift]

Unit 1 was supposed to be decommissioned soon anyway so I don't think it's loss is a problem. The fact that all the others are damages will be.

I'm really annoyed about this. We've had the media and the usual suspects running amok billing this as a new Chernobyl scaring people to death and all on false pretenses. The daily mail, the rag that brought you the anti GM hysteria and MMR scare, has been going full throttle on it.

This isn't a Chernobyl. This is maybe a TMI, aka a panic attack. And all of it was caused by one of the earthquakes ever recorded and even that couldn't cause nuclear Armageddon from a 40 year old unit. Far from raising questions about the safety of nuclear power, it is the best demonstration of it.

I agree. When I got to work yesterday several people came up to me with their concerns about the nukes and my response was, "They will figure it out.". Another friend, a cabinet designer and carpenter, complained that because of me he knew what a subduction zone was, because I had, and he quoted the comedian Ron White, "raped his ear" with information he hadn't necessarily requested, previous to the event.

[geonuc]

Nuclear powered submarines would provide another means of providing portable power for the reactor cooling systems. The American Seawolf submarine uses 40 megawatt reactors and the Russian Akula class submarines operate at 190 megawatts.
There would be less concern for tsunamis for submarines if operated off shore. You would still likely need to be hundreds of yards off shore for their required depth to operate. Then you would also need sufficient cabling to cover that distance.


Bob Clark

You don't need nuclear powered aircraft carriers or submarines to provide power to the pumps. You just need diesel-generator sets. These come in many sizes and can be portable. Moreover, the plants may have DG's dedicated to other systems, such as security systems, that can be used in a pinch. Many US plants have them (I know because we've been installing them over the last several years).

[geonuc]

Some news reports say that they are using seawater as emergency coolant. The salt water is corrosive and one interpretation was that they had decided to scrap the 40 year old plant(s).

But if they hose it down, won't the seawater carry radioactivity into the environment???

Using seawater doesn't mean they are "hosing it down". There will be releases of radioactivity to the environment; there already have been and nukes routinely release a small amount anyway. Moreover, the environment already has plenty of radioactivity.

Using seawater as an emergency coolant will doom the plant, as has been reported. The primary system piping and vessel cannot tolerate the chemical composition of seawater. That's unfortunate but the plant is old and small.

What I haven't seen reported yet - I haven't looked real hard - is why the standby sources of water are not available. I'm not talking about offsite sources - there are large holding tanks designed specifically to be used in this situation and the suppression pool under the reactors (sometimes referred to as the 'torus') is also designed to be a heat sink. It's no stretch to imagine the earthquake compromising the standby sources but they are seismically qualified. Perhaps the magnitude of the ground motion took them out. This, along with many other questions, I will interested in exploring in the months ahead.

[Jens]

Perhaps the magnitude of the ground motion took them out. This, along with many other questions, I will interested in exploring in the months ahead.

I really don't know for sure, but I suspect that the real problem in this case was the tsunami. I think that probably the water tanks outside were taken out by the tsunami, and that's why the system basically fell apart.