Dunno what he thinks, but most iodine isotopes are pretty short lived, like I-131 with an 8 day half life. If he meant that, he probably should have written it.
As for salt, it wasn’t iodized because of looming nuclear war but because the body needs it in the thyroid.
They never stopped making iodized salt. Most table salt these days is still iodized.
We have yet to shake the iron grip of the iodine cabal.
Probably haven’t seen it because my wonderful wife doesn’t use cheap salt.
It’s got coarse or sea salt or some other bullshit.
Sea salt usually has iodine in it, thought the amount is much more variable than iodized table salt.
Thanks for all the info matt, and the link, very interesting!
So, if I got this right, it seems that while it indeed looked likely on may the 14th that corium had dropped through a hole in the bottom of the reactor vessel into the dry well, on the 15th TEPCO released additional findings, their assessment for now is it has not:
What seems to be cause for concern for now in Reactor 1, is the water leakage and the rising levels of radiation encountered, which if I understand it correctly were as high as 2 Sv/Hr.
TEPCO is no longer adding fresh water to the RPV because there’s concern that the contaminated water leaks, worst case in to groundwater:
Here’s a question, maybe for Matt - if you’re up for it? Assuming that core fuel is now Corium proper resting on the bottom of the RPV - is decay heat no longer an issue, once the fuel is fully molten into Corium? It looks to me that the situation could get really hairy if decay heat is unchanged and adding more water for cooling is no longer an option because of the leakage issue!
The 2 Sv/Hr reading also sounds like bad news, given that TEPCO must get people in there to somehow restore containment integrity before they can restart cooling?
[QUOTE=SherwoodAnderson]
Here’s a question, maybe for Matt - if you’re up for it? Assuming that core fuel is now Corium proper resting on the bottom of the RPV - is decay heat no longer an issue, once the fuel is fully molten into Corium? It looks to me that the situation could get really hairy if decay heat is unchanged and adding more water for cooling is no longer an option because of the leakage issue!
[/QUOTE]
Well, Matt is who you are looking for the answer from, but you are again assuming the fuel is in a molten state…and that’s an assumption that is, once again, not based on any facts I’ve seen. However, even assuming it is molten (or I guess was molten at some point), it’s sitting in the bottom of the pressure vessel, which is covered in water. They are constantly pumping fresh water into the vessel (except when they aren’t, like when they had an issue with another quake last week). Some of that water is leaking out, to be sure, but not all of it is.
AFAIK (and Matt can correct me if he likes), the temperatures inside the pressure vessel have been pretty stable and aren’t rising. Keeping the water going in, even if some (hell, even if most) is leaking out is critical. Finding the leak or leaks is also critical, and I’m sure they are trying to work that problem as quickly as they can, but they are basically taking the leaking water out and storing it. That was why they dumped the lower level radioactively contaminated waters out of that storage and into the sea…to give them the space to suck up the higher radioactive water in the basements and flooded areas of the plant, and to take out the leaking water that is currently happening.
Restart the cooling? Perhaps I’m missing something here…why do they need to restart cooling? AFAIK, they have been cooling the cores since they were able to get power going and fresh water going back into the reactors (with a few notable interruptions) and repair or replace the pumps.
As for your point about the high levels of radiation, that’s certainly a problem, and a big part of the reason they haven’t fixed the leaks yet. IIRC, they are planning to bring in robots specifically designed to go into that environment to try and figure out what’s going on.
-XT
Yes I meant the radioisotopes of those elements, iodine 131, caesium 137 and strontium 90. The various Fukushima threads have been running for so long I assumed I could leave the numbers off because would everyone would know what I meant, and I’m lazy.
The short half-life of iodine 131 is both a blessing and a curse. Sure, six months down the line it’s decreased over a million times, but it’s radioactive as hell while it’s decaying and it’s very bioavailable, which means you have to be careful not to ingest too much of it while it’s around.
[QUOTE=xtisme]
How accurate have you found this source to be?
[/quote]
So far, very good. It draws from all the major sources - TEPCO press releases, JAIF, IAEA etc. but also digs up the technical details and General Electric’s manuals and discusses the information in a technically informed manner. It’s also fast, usually a day or so ahead of mainstream news.
[QUOTE=SherwoodAnderson]
Assuming that core fuel is now Corium proper resting on the bottom of the RPV - is decay heat no longer an issue, once the fuel is fully molten into Corium? It looks to me that the situation could get really hairy if decay heat is unchanged and adding more water for cooling is no longer an option because of the leakage issue!
[/quote]
There is no way of stopping decay heat other than to keep the cooling going and wait it out. The radioactive elements will still decay and generate heat whatever they are combined or diluted with. In normal circumstances, spent fuel is transferred to spent fuel pools where they are stored for years before they are cool enough to transfer to dry storage. As Fukushima has also demonstrated, spent fuel needs to be kept immersed or it can still get to high temperatures from its own decay heat.
If there’s a lump of corium at the bottom of the RPV, or a pile of fuel pellets, or even a congealed puddle of corium under the RPV sitting on the concrete floor of the drywell, it will still be generating heat. If its in the RPV then it may not matter by now - the experience of 3 Mile Island tells us it may be possible to just leave it there to cool down by itself in the worst case. But we’re in uncharted territory here. If it turns out that the leaked water is only making its way to the reactor basements then they may have to keep the cooling going and pump the basements into storage. If that’s the case then when online water decontamination becomes available they can presumably keep recirculating the same water through the reactors, leak path and all. However, if the water is escaping into the environment they are going to have to abandon water cooling. I don’t know what the options are if that is the case - fill the drywells with refractory concrete and encapsulate everything?
Currently the cooling is by water injection into the RPVs through various (ad-hoc?) connections. The water has to flow through the cores, whatever state they are in, and come out somewhere; where hasn’t been made clear but I’m presuming it’s flowing down the steam lines and turbine bypass to the condensers since that’s where TEPCO has arranged their water storage. Eventually a recirculating cooling system needs to be set up to prevent contaminated water from simply accumulating indefinitely.
can you save your elitist food snobbery for some other thread?
If that’s what s/he meant by ‘restart the cooling’ then yes…eventually they will need to put in place a long term system. But they have been cooling the reactors since they got fresh water, power and the pumps back online and working. Obviously what they have going is a stop gap until they get things fully back under control.
-XT
Well - in my defense - that was an assumption, but for the sake of asking a question aimed at finding out if there was a scenario where the need for constant cooling to prevent a containment failure was perhaps diminished. Assuming the fuel is in corium form, what are the implications wrt heat emission?
My interpretation of reporting in various places, e.g. at the blog that Matt linked, was that the prospect of large quantities of contaminated water escaping the primary containment and possibly into the environment, worst case ending up in e.g. ground water has forced TEPCO to abandon pouring water into the RPV of Reactor 1 until they have addressed the leakage.
[QUOTE=atomic power review 14/5]
TEPCO has reported over 3000 tons of highly contaminated water in No. 1 plant turbine building, with the amount increasing fairly rapidly. There is now absolutely no doubt in any quarters that TEPCO has lost containment on this plant.
[/QUOTE]
“Lost containment” understood to mean that contaminated water is leaving the RPV, primary containment, and possibly the reactor in an uncontrolled manner, the details of which TEPCO doesn’t know.
Here’s reporting on the scrapped plans to flood the primary containment:
[QUOTE=Asahi Shimbun]
Tokyo Electric Power Co. has been forced to devise a difficult new step to cool a reactor at the stricken Fukushima No. 1 nuclear plant after its attempt to flood the pressure vessel and containment vessel with water failed.
TEPCO said on May 14 that 3,000 tons of water found in the basement of the No. 1 reactor building had likely leaked from the containment vessel.
The utility had fed more than 10,000 tons of water into the reactor for cooling, hoping to flood the core vessel and outer containment vessel so that damaged fuel rods will be kept submerged, in a process called “water entombment.” However, some of the water apparently leaked through pipe joints in the containment vessel.
With the failure of the operation, the utility is now considering recirculating the leaked water to try to cool the fuel rods, most of which are believed to have dropped to the bottom of the pressure vessel in a meltdown.
[/QUOTE]
So my laymans speculation is that they’re faced with the unenviable dilemma of either allowing the risk of releasing up to thousands of tons of contaminated water into the environment and risk contaminating freshwater supplies, or try to do restore water containment in an environment where workers may contract radiation poisoning in less than an hour, or leave the fuel in the RPV to it’s own devices and hope for the best.
Or maybe it’s not som much about the risk of leaking into the environment that’s causing them to scrap the flooding plans, but rather the case that they’re simply not able to get the water to stay in the primary containment…
But in the end if they can’t get real people in there, doing engineering work will be pretty much impossible. Perhaps if the worst radiation is from the contaminated water, maybe they could pump it out and get radiation levels down?
[QUOTE=Matt]
There is no way of stopping decay heat other than to keep the cooling going and wait it out. The radioactive elements will still decay and generate heat whatever they are combined or diluted with. In normal circumstances, spent fuel is transferred to spent fuel pools where they are stored for years before they are cool enough to transfer to dry storage. As Fukushima has also demonstrated, spent fuel needs to be kept immersed or it can still get to high temperatures from its own decay heat.
If there’s a lump of corium at the bottom of the RPV, or a pile of fuel pellets, or even a congealed puddle of corium under the RPV sitting on the concrete floor of the drywell, it will still be generating heat. If its in the RPV then it may not matter by now - the experience of 3 Mile Island tells us it may be possible to just leave it there to cool down by itself in the worst case. But we’re in uncharted territory here. If it turns out that the leaked water is only making its way to the reactor basements then they may have to keep the cooling going and pump the basements into storage. If that’s the case then when online water decontamination becomes available they can presumably keep recirculating the same water through the reactors, leak path and all. However, if the water is escaping into the environment they are going to have to abandon water cooling. I don’t know what the options are if that is the case - fill the drywells with refractory concrete and encapsulate everything?
[/QUOTE]
Once again, thanks for the all the info.
So that’s like the Chernobyl Sarcophagus option? But they’d have to get all the water out first?
So, let me see if I’ve got this. 190 tons of water a day is being pumped in, presumably to replace water which was there, but now isn’t. That water is gone,it is has gone down a series of sluices and pipes to “storage”. Where it is being contained, presumably, since it being stored. 190 tons of water per day.
As a registered mathtard, I am daunted. Am I wrong to find this figure outlandish? To wonder who built such a massive water containment system, and why? Did they build it for just such a contingency? A swimming pool for Godzilla?
This makes sense?
I might have missed where you got that 190 tons of water a day figure, but they had some fairly large storage facilities on site that a lot of that contaminated water is being pumped into, and I know that there are (or were) treatment facilities at the plant that should be able to do a lot more than 190 tons of water per day (over a million tons per day shouldn’t be all that much of a stretch).
I’m not sure how much water they are injecting per day, and how much of that is leaking out and has to be stored with the other contaminated water (I seem to recall them saying that there were several thousand tons of water in the basements of the reactor buildings, but I might be mis-remembering). Also, some of that water is being converted to vapor, IIRC, which is also still a problem (since the vapor is contaminated as well).
-XT
A tonne of water is a cubic metre. A standard Olympic swimming pool is about 3000 tonnes of water. The plant has lots of water storage - the surge tanks for the toruses are 3400 cubic metres each, the condensate storage tanks are 1900 cubic metres, the condensers themselves can hold 1600. I don’t know how much the plant’s radioactive waste management facility can hold, but it’s a lot. The “megafloat” barge due to arrive can hold 10,000 tonnes.
And it still isn’t enough to deal with all the water in the turbine halls. They’ll have to decontaminate it and pump it into the sea. But it is enough to prevent the water they’re pumping in from overflowing the basements and trenches, for the moment.
Thought I was quoting something in this thread, but here is one source, amongst any number:
http://www.aseanbusinessforum.com/news/allDetail.php?id=18916&sec=1
Further on:
Like, the water is leaking out the hole cut in the bottom by the molten fuel? :eek:
Some guy at work has a facebook friend in Tokyo who says people are wearing masks all over the city. Kids go out only in masks, hats and gloves and don’t play outside anymore, haven’t for 2 months. Not just the Tokyo facebook friend’s kids, but all the kids in Tokyo.
Sounds like a rumor. Then again, apparently there has been a reactor core meltdown in Fukushima.
:eek:
No, this isn’t true. Plenty of kids out playing in Tokyo, and mostly without masks, and the ones wearing the them are doing so for another reason.
Shortly after the mess started, and number of photos / videos were shown with people wearing masks, but what generally hasn’t been reported is that this is hay fever season and every years many, many people wear masks.
This has been a good thread, and I hope it can stay on topic.
One of the frustrating aspects of living here in Tokyo, with children, is trying to guess the actual levels of danger (which Tokyo has never been in direct danger) and what needs to be of concern (is seafood safe?), and what is just going to be a problem for Fukushima and not Tokyo.
Unfortunately, Tepco has not been forthcoming with data, so it’s not clear what is happening. Various international organizations have repeatedly complained about this. Hell, the Prime Minister was caught with an open mic complaining about the lack of info from Tepco, and if he can’t get it, then what chance do ordinary residence stand?
From the latest NHK report
There is a question of how much testing is being done for strontium 90, which is one of the major concerns. Radioactive strontium is treated by your body as calcium, so it gets deposited into your bones. Many of the deaths after Hiroshima and Nagasaki came from this radiation.
Tepco detected strontium 89 and 90 in the ocean on samples taken April 18, but didn’t announce it until May 8th, some three weeks after the sampling.
Most sources say that a preliminary announcement could be expected in about a week, and a final confirmation within two. The delay is inexplicable.
To the issue of whether the fuel pellets have melted and are now Corium or not, the assessment of TEPCO seems to be that they are at least partially molten:
Asahi Shimbun 17/5: TEPCO: Meltdown at No. 1 reactor started much earlier than initially reported
[QUOTE=Asahi Shimbun]
Reactors at the plant automatically shut down at 2:46 p.m. on March 11, when the Great East Japan Earthquake struck. This also knocked out the plant’s emergency system to provide power from external facilities.
The tsunami struck around 3:30 p.m., destroying the plant’s emergency power generator, resulting in a total power failure at the plant.
Due to a lack of immediate means to cool the reactors, the cooling water in the nuclear core started evaporating amid the intense heat from the fuel rods.
Around 6 p.m., the water level fell below the upper ends of the fuel rods, leading to partial exposure of the rods and causing the temperature inside the nuclear core to jump.
About 90 minutes later, all 4-meter-long fuel rods were exposed.
The metal casings of the rods began melting, especially among those in the lower middle of the core, when the temperature reached 1,800 degrees.
Twenty minutes later, the upper middle part of the core collapsed as it melted. By 9 p.m. [on March 11], the temperature is believed to have reached 2,800 degrees, at which the fuel pellets started melting.
By the next day, all the fuel had melted and fallen to the bottom of the pressure vessel, according to TEPCO.
[/QUOTE]
And from Atomic Power Review, we have:
[QUOTE=Atomic Power Review, 15/5]
MARCH 12 2011
01:20 Report of rapid rise in primary containment pressure
05:50 Begin injection of fresh water to core
[…]
20:00 Begin injection of sea water (borated) {one source says 20:20}
[…]
SOME CONCLUSIONS.
[…]
-Injection of borated seawater at 20:00 on the 12th was far too late. The first source used should have been borated.
[/QUOTE]
So, we then have TEPCO’s assessment that core temperature reached 2800 degrees at 21.00, march 11th, at which point the fuel pellets themselves started melting. Injection of fresh water started about nine hours later, at 05.50 march 12th. Borated sea water was then injected at 20:00.
A question for e.g. Matt: what is the significance of the water added being borated water or not?
Boron is an excellent neutron moderator, it would have been for the immediate protection of personnel and facilities. Not using it might have increased the dose picked up by employees around there but more likely allowed more of the metal infrastructure to become activated (made radioactive). It probably has increased the current background by a little bit, most likely Fe-59.