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Fukushima Radiation Levels High, But Leak Plugged
jmcvetta wrote in with a story about Fukushima radiation levels so high that monitoring devices have been rendered useless. Levels outside the buildings exceed 100 millisieverts in some places. But the good news is that the leak is patched using 1500 liters of sodium silicate.
Helpful radiation chart for those of us who don't have a clue whether 100 millisieverts is a tiny dose or enough to create a Godzilla monster.
In short, it's definitely into the "You might want to step-up your planned schedule on those cancer screenings" territory.
SJW: Someone who has run out of real oppression, and has to fake it.
100 millisieverts? Per hour? Per day? Per century? Thanks, Slashdot, for giving us a useless number.
"I zero-index my hamsters" - Willtor (147206)
The leak that was stopped was from a drain pit to the ocean. The reactor itself is still leaking highly radioactive water. They're running out of places to put it.and are frantically building tanks and ponds.
There is an estimated 50,000 tons of water still on site that will need to be disposed of one way or the other. About 500 tons are pumped into reactor pressure vessels for cooling every day. Some recent information on this is reported here by NHK: Workers face challenge of water storage
To put 50,000 tons of water in perspective, a super tanker will carry about 172,000,000 gallons of oil. 50,000 tons of water is ~12,000,000 gallons. One super tanker could carry all the water on site plus and also receive all new water pumped into the reactors for the next 1332 days. No, I don't need the plausibility of this explained to me; this is an attempt to provide some scale to the problem.
Lurking at the bottom of the gravity well, getting old
So according to the chart, if you hang around an area with 100 mS per hour for an hour, you'll receive a dose likely to cause cancer. Hang around for 4 hours, and you get radiation poisoning. That's not a lot of time - it takes days of labor to do anything major. Probably takes 30 minutes just to walk around part of the plant looking for radiation leaks. This must be why it took so long to plug that water leak - no one could hang around the leak for more than brief intervals.
Heck, even refueling a diesel pump - which is just increasing the amount of highly radioactive water you have to dispose of somehow - is going to take 20 minutes at a minimum, right?
I'm sure the workers are doing what they can - sprinting through the hot areas, working in shifts, using automation when they can - but the larger the contaminated area gets and the more fission products leak the worse the problem becomes. If you cannot even enter the building the reactor is in, how can you fix anything? They can't just send in robots and spray concrete willy nilly - if the reactor cores fully melt down and form critical masses at the bottom of the reactor vessel, gigawatts of heat will be produces and burn through any containment.
They need to have active pumps flushing water through the reactor vessels and out to the cooling tower and back again. This is the only method that won't create more and more radioactive water that has to be disposed of. (because right now they are just pumping water in and it leaks out of the reactor vessel and pools somewhere)
But to do that, somehow has to enter the building, install new pumps, fix breaks in the wiring, fix holes in the pipes, install sensors, power it up, and so forth. That's many hours of labor, and beyond the dexterity of what robots can do.
http://xkcd.com/radiation/
Japan's ocean radiation hits 7.5 million times legal limit
TOKYO â" The operator of Japan's stricken Fukushima nuclear plant said Tuesday that it had found radioactive iodine at 7.5 million times the legal limit in a seawater sample taken near the facility, and government officials imposed a new health limit for radioactivity in fish.
The reading of iodine-131 was recorded Saturday, Tokyo Electric Power Co. said. Another sample taken Monday found the level to be 5 million times the legal limit. The Monday samples also were found to contain radioactive cesium at 1.1 million times the legal limit.
The exact source of the radiation was not immediately clear, though Tepco has said that highly contaminated water has been leaking from a pit near the No. 2 reactor. The utility initially believed that the leak was coming from a crack, but several attempts to seal the crack failed.
http://www.mcclatchydc.com/2011/04/05/111571/japans-ocean-radiation-hits-75.html
"Flyin' in just a sweet place,
Never been known to fail..."
(emphasis mine)
They are being totally selfish and turning a blind eye to what the government has been trying to tell them. They have many millions more gallons of water than they can store. Some of it has to be dumped. They could dump some less contaminated water from the storage pond to make room for much more dangerous water that has to be removed from the reactors, OR they could stop using the pond and just dump that highly radioactive water from the reactors straight into the ocean, which would be much worse for the fishing industry over the next several years. No one else has a better idea, unless these fishermen care to stop by with some buckets?
They're upset at what's happening, and are lashing out and treating it like they're the deliberate targets of a random malicious decision. It's the best option available at this time. I don't even know if a technology exists to remove radiation from water, I'm assuming it either doesn't exist or is too slow to be practical otherwise they wouldn't be using storage ponds in the first place.
I work for the Department of Redundancy Department.
Not a problem, we'll just throw the fish in jail and we'll be good to go.
It is in Parsecs
* Winners compare their achievements to their goals, losers compare theirs to that of others.
Even if they get the hydrogen under control, the amount of water, the damage to the secondary containment, the likely damage to primary containment, the contamination of the site, it's not just that Fukushima Daiichi will never operate again. Daiichi will be entombed and left to decay for at least a decade, probably longer, much longer. All six reactors are lost, 5&6 are just not going to be operated because it is too hot to work there 8 hours a day.
While they wait for decay to lower levels enough for machines to clean things up, there will be continuing groundwater and soil contamination. They will have to build a new seawall and interceptor wells to limit (not prevent) contamination of the local sea. The local population won't be allowed within 12km, and they won't WANT to be within 20km or more. Agriculture will likely be ruined, having to wait for years to once again export their products. It's the Cesium isotopes that will cause the worst problems, and cause the lasting effects, and they are not able to contain this yet. Hopefully #3 won't blow a Plutonium cloud that, even if it were minimal, would poison the area for the forseeable future. There is no assurance that this will not happen.
This is already inevitable, and there will be no real discussion, because TEPCO cannot admit to the inevitable outcome yet. To do so is to admit defeat, lose all face, and watch them become a single-yen stock.
And somehow Japan needs to replace the generating capacity. Quickly.
Overall this situation is redefining 'worst-case'. It may have been simpler to have a couple of core melts and just pour concrete and sand over the whole damned thing. Now we've gotten broken containment, multiple vectors, and inadequate resources. Oh, and the Japanese way of self-reliance to the point of failure. Works for the residents and their migration, doesn't work for engineering problems.
deleting the extra space after periods so i can stay relevant, yeah.
I'd like a machine that can travel at 100 mS per hour.
I think they call it a Tardis. It's just not a very good one.
Workers are pumping nitrogen into one of the reactors at Japan's damaged nuclear plant in an attempt to prevent an explosion caused by dangerously overheated fuel rods.
Officials at TEPCO, which operates the Fukushima plant, said a dangerous hydrogen buildup is taking place at its number-one reactor. Japan's NHK television quoted officials saying hydrogen is accumulating inside the reactor's containment vessel - an indication that the reactor's core has been damaged.
Crisis at Japan Nuclear Plant Shifts to New Blast Risk
Chemistry 201: Why Is Fukushima So Gassy?
But there are reasons...that Fukushima is particularly vulnerable.
One is its recent use of seawater to cool the reactors's fuel rods and cores. In addition to the oxygen in water molecules, cold seawater can hold a great deal of dissolved oxygen gas. But warm water cannot; so as the seawater was heated in the reactor, the dissolved oxygen emerged and gathered in the empty space above the water.
(Ordinary reactor cooling water has had the oxygen removed from it by plant operators to reduce the possibility of rust.)
In addition, gamma radiation from the nuclear fuel in the reactor would continuously produce small amounts of hydrogen and oxygen by breaking up water molecules --- and the normal method of recombining these elements into water at such plants in a controlled fashion is no longer available.
Plants of the Fukushima variety usually have catalytic converters that accomplish that at the point where steam has run through the turbine and is condensed back into water for another trip through the reactor. But that path has been closed since the plant lost power at the moment of the March 11 earthquake.
Hydrogen can also emerge from the zirconium metal used as fuel cladding. One of the lessons of the Three Mile Island accident in 1979 near Harrisburg, Pa., is that when the cladding comes into contact with steam rather than water, it goes through a reaction that is akin to rusting; it picks up oxygen from the water molecule and gives off hydrogen.
This only happens at high temperatures, but uncertainty reigns at the moment about temperatures in the Fukushima reactor cores. With some cooling channels blocked, they are likely to have hot spots.
By design, boiling water reactors like these have far more zirconium metal in them than pressurized water reactors do. They boil water directly in the core, covering the fuel assemblies with a water/steam mixture rather than keeping them immersed in water. The water has to be directed to each individual fuel assembly and therefore each sits in its own zirconium box.
All of that zirconium is available for an oxidation reaction with steam in which the metal absorbs oxygen from water and turns to a powdery rust, releasing hydrogen.
And connects to a drain at the bottom of a pit underneath a nuclear reactor. And this is to help when they wax the floors? This is to clean up after barbecues? This drain is used when the have the weekly trim everyones hair day underneath the reactors? Considering these buildings are supposed to be nearly hermetically sealed, why the snot do the plans call for a pipe that goes out the the friggin ocean?
I, for one, preping to welcome our new Godzilla overlords.
The yellowcake is a lie!
You can't change that... by gettin' all... bendy.
What I don't see enough discussion about is the bioaccumulative effect.
For catch-up: fat-soluble toxins can accumulate in the bodies of organisms such that at every step of the food chain, the concentration is multiplied. It's not just a single species accreting the toxin, but what happens when its predators are eating from this concentrated source. Any links up the food chain up to the apex predator are going to have a multiplied effect, which is why a seemingly insignificant amount of mercury pollution versus the ocean's volume has made tuna consumption a point of caution.
We are seeing radiation levels that could be a bit of a concern and the Fukushima situation is still not under control. And are some of the compounds it's emitting bioaccumulative? Yes, Cesium 137 for example, and that has a half-life of 30 years. And the first thing you should do is move your consumption as far down the food chain as possible. Even if you don't plan to go vegan, learn Indian cooking or a low-meat cuisine, because the less animal product you're consuming, the better.
Sources:
http://www.ncbi.nlm.nih.gov/pubmed/11482657
http://www.marietta.edu/~biol/102/2bioma95.html
http://science.jrank.org/pages/854/Bioaccumulation.html
http://www.businessinsider.com/san-francisco-rainwater-radiation-181-times-above-us-drinking-water-standard-2011-4
Well it does look like they have finally got this under control, at least for the most part.
Plugging one leak does not mean the situation is even close to being under control. Hidehiko Nishiyama, a spokesman for the Japan's Nuclear and Industrial Safety Agency, said:
... no further leakage has been detected from the pit. But there is a possibility that the water, which has lost an outlet, could show up from other areas of the plant.
The highly radioactive water is believed to have come from the No. 2 reactor core, where fuel rods have partially melted, and ended up in the pit. The pit is connected to the No. 2 reactor turbine building and an underground trench connected to the building, both of which were found to be filled with highly contaminated water.
Thousands of tons of highly radioactive water had already been found in many places outside the reactor buildings even before the direct leak into the ocean was discovered. Is there anything more substantial than crossed fingers and wishful thinking that makes you think the flow of highly radioactive water will halt now that they've plugged the direct outlet into the ocean?
In addition:
According to estimates by TEPCO announced Wednesday, 25 percent of the nuclear fuel rods have been damaged at the No. 3 reactor. The company earlier said that 70 percent of the No. 1 reactor's fuel rods and 30 percent of the No. 2 reactor's fuel rods have been damaged.
Nishiyama said past hydrogen explosions have likely occurred due to hydrogen accumulation caused by the reaction of melted fuel rods' zirconium with steam from the coolant water. But now there is concern that hydrogen could accumulate in the No. 1 reactor under a different process involving radiation-induced decomposition of water into hydrogen and oxygen.
The installation of billion dollar radiation shielding around the reactor buildings has to be delayed until at least September because, of the high level of radioactivity. In other words, they need to wait for the current levels of radioactivity to decay before it is safe enough to install radiation shielding. So, ISTM, the September date is optimistically assuming the ongoing contamination will magically stop. Yet, even if the shielding could be installed tomorrow:
Some experts were sceptical about the feasibility of the measure as the step would have only limited effects in blocking the release of radioactive substances.
That is because the bulk of the release of radioactivity is downward in the water, not upward into the air. The shielding story highlights the challenge they are up against. The level of radioactivity around the plants (and in the plants) is so high, it is impeding their efforts to control the amount of radioactivity escaping. For example, work to restore the primary cooling system for reactor #2 has been halted for almost two weeks because of the high levels of radiation in the turbine building. The radiation level, due to highly radioactive water in the building, is over one sievert per hour. So a worker hits their lifetime dose limit less than 15 minutes. Someone who lingers there for an 8 hour shift will die regardless of what treatment they receive. It's been reported that the level of radioactivity in reactor buildings 1, 2, and 3 is too high to measure.
They are pouring hundreds of tons of uncontaminated water onto (into?) the reactors every day to cool them. Thousands of tons of this water has come out contaminated with radioactivity and has flooded the turbine buildings, tunnels outside the buildings, and the ground. They don't know how the water is getting contaminated or the routes it is taking
We don't see the world as it is, we see it as we are.
-- Anais Nin
I get what you are trying to say with this, but honestly when everyone says its safe, yet these kind of "accidents" can still occur it makes you step back and really weigh the positives and negatives.
For instance, in these plants they are using plutonium mox fuel. That shit has a halflife of 20,000 years. So it wont be completely nonreactive for approximately 250,000 years or 12000 human generations. Sure it shouldn't happen, and there were no doubt many mistakes by this particular company. But even if it is a possibility that this would happen, and it obviously is, should we not reconsider the long term environmental and other effects when we are possibly going to be affecting forward 12000 generations in the future?
So far in my life time (30 years) there have been 3 major nuclear accidents. Does this not at least warrant a second look? There are plenty of these unsafe plants active in the world, and yes I am aware there are safe reactor designs (CANDU). But when you factor in human greed, nuke plants run by the lowest bidder, should we even be doing it?
I was VERY pro nuclear power before this complete mess that has happened. Even though we will run out of uranium by 2100, even though fuel stays reactive for tens of thousands of years. But honestly, if the japanese cant even do it right, what hope do we have for any country out there?
The timescales alone are enough to make one pause. Can you really trust the next 12,000 generations of man to not have any accidents with spent fuel? Is that something that we should be burdening our future generations with for a short term gain today?
Further reading: 'No safe levels' of radiation in Japan
As a potential lottery winner, I totally support tax cuts for the wealthy
Considering these buildings [the reactor buildings] are supposed to be nearly hermetically sealed, why the snot do the plans call for a pipe that goes out [to] the friggin ocean?
Your mistake was believing the bullshit some people have been spouting that the reactor buildings were a third layer of containment after the ziroconium clad fuel rods and the containment vessel. Here is excerpt from an article from earlier in the crisis called Containment vessel failure unlikely:
The containment vessel is the last line of defense for containing lethal radioactive materials, and significant damage would pose grave safety concerns.
Drains and tunnels actually make sense. When a reactor is functioning properly, almost all of the radioactivity is contained within the zirconium clad fuel rods. The water circulating around the rods that acts as both a cooler and a moderator (a moderator slows neutrons down to enable the chain-reaction) is not highly radioactive. For example, the water that flooded the turbine building for reactor #2 and a nearby tunnel is 100,000 times more radioactive than the water found inside a functioning reactor. I believe the water that was pouring into the ocean from the pit was only 10,000 times more radioactive. The drain was also never intended to pass tons of water (radioactive or not) into the ocean. The amount of radioactivity was probably more than 6 orders of magnitude greater than what was intended.
Your observation highlights the fact that the reactor buildings were never designed or intended to be a serious containment in the event of the failure of the containment vessel and fuel rods. Tens of thousands of tons of highly radioactive water have already escaped via routes other than the direct drain into the sea. It is therefore highly unlikely that plugging that drain will substantially reduce the amount of radioactivity that is spewing from the reactors.
We don't see the world as it is, we see it as we are.
-- Anais Nin