risk from Unit 4 to the Northern Hemisphere (to Mark & BRAWM)
Lately the facebook sky-is-falling commmunity has inferred that Unit 4 is on the edge of blowing up or whatever it's feared it may do and leave only the lucky inhabitants of lands south of the equator to inherit a newly irradiated earth. While I seem to remember even Arnie G mentioning that the radiation from Unit 4 wouldn't have the required propulsion to make it far beyond japan's airspace without an explosion like we saw on 3/11/11 (which couldn't happen, right?), I must admit I feel somewhat troubled by this collective apprehension. Would Mark or anyone else who has an informed opinion like to weigh in on the relative safety of us sitting on the north half of the globe from receiving yet another (possibly worse) dousing of radionuclides in the (near) future?
thanks. my sanity has and continues to be fostered by this forum.
AR 5/3/12
Bump... interested in BRAWM
Bump... interested in BRAWM comments. Thank you.
Hmm
http://www.tepco.co.jp/en/nu/fukushima-np/info/index-e.html
Current TEPCO "Important Report' regarding the stability of Unit 4 in the event of another earthquake.
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I get that they're trying but somehow this really just does not make me feel any better.
- JMS 05/06/12
http://www.dailykos.com/story
http://www.dailykos.com/story/2011/03/23/959224/-Fukushima-Fuel-Storage-...
Each reactor has a spent fuel pool and there is a common pool that sits 50 meters away from the reactors. Some of the fuel assemblies are fresh and pose no radiation risk. Some have been irradiated and contain fission products. After one year of sitting around mainly Cs-134, Cs-137 and Sr-90 are putting out radiation and heat. No need to stock up on Iodine pills, the I-131 has all decayed away.
Spent fuel in the individual pools: 800 tons total
Cs-137: 725e6 gm spent fuel * 0.04 (original U235 content) * 0.06 (Cs-137 / fission * 88 Ci/gm * 3.7e10 Bq/Ci = 5.6e18 Bq Cs-137
http://en.wikipedia.org/wiki/Chernobyl_disaster#International_spread_of_...
The long lasting effect of Chernobyl was to spread Cs-137 around the Ukrainian countryside.
Total release of Cs-137 estimated as: 85e15 Becquerels from 180 tons of fuel
Lower limit of contamination for monitoring: 37 kBq/m2
Area of earth surface: 510e6 km2
Contamination if all Cesium was released and spread evenly over the northern hemisphere: 5.6e18 Bq / (510e6 km2 / 2.0) = 22e9 Bq/km2 = 22 kBq/m2
From Chernobyl experience 10% release is more realistic: 2.2 kBq/m2
Not quite enough to cause the northern hemisphere to be abandoned.
What happens if the pool collapses? Water serves as both a coolant and a radiation shield.
5.6e18 Bq of Cs-137 puts out 575 kW of gamma rays.
8 feet of water reduces gamma rays by 2e9. Without shielding fatal radiation fields will prevent approach to the facility.
Fatal dose = 10 Sv = 10 Joules/kg = 1000 Joules for an average 100kg person.
Surface area of human: about 2.0 m2
at 100 m: 2.0 m2 / (4pi 100m * 100m) * 575 kW = 9 Watts = .09 Sv/s, death in 1.5 minutes at 100m distance.
Best option if the pool fails. Bulldoze a lot of earth over it and let it bubble away as a mass of corium. It's better all in one place than dispersed over the country side.
So, to continue, spreading
So, to continue, spreading Cs-137 on the ground where you live is a bad thing.
How about dumping it in the ocean? How bad is that.
Volume of the ocean: 1.3e21 liters
mcl for Cs-137 in drinking water: 200 pCi/l = 7 Bq/l
So if we dumped 1e22 Bq of Cs-137 in the ocean we would reach the epa limit for Cs-137 in drinking water.
That amount of Cs-137 would disappear at the rate of 231e18 Bq/year through radioactive decay.
So we could dump 231e18 Bq/year into the ocean and we would reach an equilibrium concentration equal to the epa limit for drinking water. Which would be the equivalent of 33,000 tons per year of spent fuel.
So if you're going to pursue a nuclear energy policy one thing you could do with the spent fuel is to reprocesses it to separate out the Cs-137 and dump it in the ocean. Disperse it and let it decay away naturally.
But, 33,000 tons per year is not a lot. Certainly just a fraction of what would be required to provide the world with a North American level of energy consumption through nuclear energy.
Otherwise it's got to go into dry cask storage. After 5 years the Cs-134 has become a minor source of heat and there's not much value to waiting any longer to take it out of the pool and put it in dry cask. Dry cask typically contains spent fuel elements generating about 24kW of heat, air cooled, with enough concrete around it to reduce the radiation level at the cask surface down to 20 microSv/hour. With a half-life of 30 years for Cs-137 and Sr-90, 300 years of storage would be needed for radiation levels to drop to 1/1000 of the original level.
That's a lot of casks to keep around.
Very helpful summary
Would really appreciate BRAWM weighing in on this if they have anything to add.
The health effects of this
The health effects of this further catastrophe-in-waiting stagger the imagination. If one of these pools goes, it will release such an insane amount of radiation that humans won't be able to get within miles of the entire complex without receiving a lethal dose of radiation within minutes. Which means that they would not be able to maintain the jury rigged cooling systems at the other spent fuel pools (or the melted down reactors), and then these other ones would go up in flames. If one pool goes, they will all go before long. There are about 1,700 TONS (That is 3.4 million pounds, folks!) of lethal spent fuel stored in these pools, containing a full spectrum of incredibly toxic radionuclides which have more contamination potential than the fallout potential of the world's entire combined nuclear weapons arsenal. (Add up the rest of the world's stockpile of nuclear waste to get a glimmering of the utter insanity of nuclear energy).
As to the problem of removing the spent fuel from these pools, the situation is even more difficult that this article describes. It isn't simply that the loading cranes were destroyed in the explosions, the situation is much more problematic than that. Another obvious difficulty is due to the structural precariousness of the damaged buildings, and the fact that debris will need to be removed in order to get at the pools. Some of the fuel rod assemblies are not intact, and in fact nobody knows yet what will be discovered in some of the pools when the debris is removed.The fact that radiation levels are so high at the reactor buildings and pools that humans cannot work there presents an enormous technical challenge. And then there is the problem that spent fuel cannot simply be taken from a reactor and placed in dry casks, as the article implies. Newly removed spent fuel releases way too much heat (and radiation) to do this for about ten years after it is removed from the reactor core... it MUST be kept in water to keep it cooled during this time. Only fuel which has cooled sufficiently can be placed in dry casks.
So the challenge with these pools is simply to do something that has never been done before... transport "hot" spent fuel to offsite holding pools, using remote controlled robots that have not yet been built, very likely requiring radiation resistant electronic systems that have not yet been invented... and we need to do it six months ago.
If it wasn't for this site...
I have to say that I worry every day and check this site once a day to see how things are going....if you know what I mean. I live on the West Coast (Santa Barbara).
Most everyone I personally know, including my family, pooh-poohs my concerns and I feel that I am hanging out here all alone. So, I keep my concerns and worries to myself now.
So, I, too, have to say that if it wasn't for this site, I don't know what I'd do.
http://www.alternet.org/healt
http://www.alternet.org/health/155283/the_worst_yet_to_come_why_nuclear_...
I had a really hard time sleeping again last night. This is almost too much to bear. I know worrying doesn't help at all, but this is horrible to contemplate.
Where is the Bill & Melinda
Where is the Bill & Melinda Gates Foundation and all the Royal Families when you need them!
Ditto
I too would like to hear what BRAWM has to say. As one of the early lurkers, I have been following since the beginning and I am continually battling back the waves of panic cause by the "tin foil hat" crowd but also frustrated at those who laugh at the idea that there is anything wrong. There has to be a middle ground somewhere. I am, however, concerned at the current status of Unit 4 and also wonder what BRAWM has to say on the matter.
JMS 05/04/13
Mark of BRAWM has addressed this
Mark of BRAWM addressed this in another thread:
http://www.nuc.berkeley.edu/forum/218/one-more-ocd-question.2012-04-17#c...
Very low danger
Unit 4
Yes, I would like to hear about the possibility as well. Not that I can do anything about it.
A few nights ago, my significant other and I layed in bed discussing the reality of unit 4 blowing her top. As the world marches on to their own agendas, I wonder how close are we to a nuclear holecost.
Japan shakes her belly often enough and unit 4 looks like a trainwreck of shakey scaffolds, and broken dreams.
What is the cost? The cost in dollars, the cost in lives?
The ocean sweeps all the radioactive water around in her tides and we are all sucking down hot particles, but at lower levels. What happens to us when unit 4 decides to blast her radiant stuff around??
AR- +1 on the sanity.
AR-
+1 on the sanity. Seriously, this place helped to keep ME from melting down.
BC 5/3/12