The crippled nuclear plant at Fukushima is losing its two-year battle to contain radioactive water leaks and its owner emphasized for the first time it needs overseas expertise to help contain the disaster.
Tokyo Electric Power Co. (9501) is grappling with the worst spill of contaminated water since the March 2011 earthquake and tsunami caused a meltdown at the Fukushima Dai-Ichi plant. The call for help from Zengo Aizawa, a vice president at the utility, follows a leak of 300 metric tons of irradiated water. Japan’s nuclear regulator labeled the incident “serious” and questioned Tepco’s ability to deal with the crisis. Prime Minister Shinzo Abe made similar comments earlier this month.
A nuclear expert has told the BBC that he believes the current water leaks at Fukushima are much worse than the authorities have stated.
Mycle Schneider is an independent consultant who has previously advised the French and German governments.
He says water is leaking out all over the site and there are no accurate figures for radiation levels.
Meanwhile the chairman of Japan’s nuclear authority said that he feared there would be further leaks.
The ongoing problems at the Fukushima plant increased in recent days when the Tokyo Electric Power Company (Tepco) admitted that around 300 tonnes of highly radioactive water had leaked from a storage tank on the site.
The Japanese nuclear energy watchdog raised the incident level from one to three on the international scale that measures the severity of atomic accidents.
This was an acknowledgement that the power station was in its greatest crisis since the reactors melted down after the tsunami in 2011.
But some nuclear experts are concerned that the problem is a good deal worse than either Tepco or the Japanese government are willing to admit.
Some 1,000 tanks have been built to hold the water. But these are believed to be at around 85% of their capacity and every day an extra 400 tonnes of water are being added.
“The quantities of water they are dealing with are absolutely gigantic,” said Mycle Schneider, who has consulted widely for a variety of organisations and countries on nuclear issues.
“What is the worse is the water leakage everywhere else – not just from the tanks. It is leaking out from the basements, it is leaking out from the cracks all over the place. Nobody can measure that.
Yes, it’s horrible for the people of Japan and especially those who lived close to the plant.
One of our great problems as a species is to always favor the short-term over the long-term. We do it with fossil fuels, and we do it with current nuclear power. We don’t know what to do with the waste, so let’s just have the following generations worry about it. When building a plant, the chances of an accident are low, so why worry? It’s not our concern.
This short-term thinking gets us in trouble again and again and again.
Tepco is pouring water and boric acid over the melted reactors in an attempt to prevent nuclear chain reaction (fission) and to prevent the spent fuel from burning. Recent steam from Unit 3 seems to indicate that the melted core is still undergoing chain reaction and producing heat.
http://www.fukuleaks.org/web/?p=10700
http://www.infiniteunknown.net/2013/07/18/‘cold-shutdown’-in-japan-steam-rising-again-from-fukushima-reactor/
Talk of cold shutdown is meaningless. In cold shutdown a normal reactors control rods have stopped the reaction and temperatures have been safely reduced so no further reaction can happen.(without cooling) A normal reactor core is a highly controlled structure. The reactor cores at Fukushima are completely melted into a pile of lava-like uranium with holes in the reactor vessel underneath it. There is no way to be sure it will not create occasional bursts of criticality in the future, because its state is unknown.
If the reactors were in cold shutdown, no water need be poured over them to prevent further chain reaction. They just redefined the word to soothe the masses. They are trying to leave the impression that the cores are safely controlled. In fact, they have never stopped pouring water and boric acid over them to prevent uncontrolled chain reaction and they have no idea when or if they can stop doing that or even if a chain reaction might occur despite their efforts. That is Tepco’s idea of “cold shutdown”.
Units 1, 2, and 3 melted reactors must be prevented from fissioning. Units 1,2,3, and 4 spent fuel must be cooled to prevent it from burning. What a mess.
http://www.globalresearch.ca/announcement-of-cold-shutdown-of-fukushima-reactors-is-based-on-a-political-decision-not-science/28353
http://www.nytimes.com/2011/11/03/world/asia/bursts-of-fission-detected-at-fukushima-reactor-in-japan.html?pagewanted=all&_r=0
http://en.wikipedia.org/wiki/Criticality_accident
thanks for the links.
got anything more recent on the water/boric acid/cold shutdown thing?
Units 1, 2, and 3 at Fukushima Dai-ichi had a total thermal capacity of 6142 thermal megawatts, and if I recall correctly they were all at 100 percent on the morning of 3-11. Set to its decay-heat setting, http://www.energyfromthorium.com/javaws/SpentFuelExplorer.jnlp says fuel that has been going at 39 MW per tonne heavy metal will, after 2.49 years shut down, be down to 4.84 kW/tHM, about an 8000th of the time average of the pre-shutdown power over a similar interval.
So, 0.76 megawatts.
In BWRs, drives coupled electromagnetically to control blades haul them down, against the resistance of springs, to let supercriticality occur. On 3-11 the loss of power let these blades spring back in. When the cores melted, the control blades were included in the melt. This guaranteed fission couldn’t restart, and nothing in the mean time has suggested any restart was occurring.
Had neutron poisons not been included, another stumbling block for fission would have been the tendency of the melting and slumping process to consolidate the dense materials, not leaving the necessary interspersal of fuel-filled regions extending a few centimetres and similarly sized void regions; had these latter regions existed, their refilling with water would have allowed moderation to be restored. Recall that no dense pile of natural uranium, nor of low-enriched uranium, can support fission, even if it fills all space.
If it is true that the post-meltdown coolant has included boric acid, that’s a third stopper; and the nuclear industry’s approach has always been belt, braces, and suspenders, so it may well be.
Arcus is quoting bad guys who were counting on your not remembering about the need for heterogeneity, and perhaps not knowing where to look for decay heat data.
Yes. Tepco continues to downplay recriticality, but there is plently of ongoing evidence otherwise.
http://fukushima-diary.com
Here is a very good synopsis:
http://news.nationalgeographic.com/news/energy/2013/08/130821-fukushima-latest-leak-how-is-it-different/
http://news.nationalgeographic.com/news/energy/2013/08/130807-fukushima-radioactive-water-leak/
Strontium-90 leaking to the ocean is another simmering issue. In some ways, its more troublesome than Cesium.
Here is how dangerous the leaking tank is:
The new storage tank leak presents a different and potentially more serious problem than the ongoing groundwater flow leaks. The water from the leaking tank is so heavily contaminated with strontium-90, cesium-137, and other radioactive substances that a person standing less than two feet away would receive, in an hour’s time, a radiation dose equivalent to five times the acceptable exposure for nuclear workers, Reuters reported. Within ten hours, the exposed person would develop radiation sickness, with symptoms such as nausea and a drop in white blood cells.
More about the levels of strontium-90:
http://www.pbs.org/newshour/bb/world/july-dec13/japan2_08-08.html
Odd topic a little, and mostly unrecognized:
http://www.bellona.org/articles/articles_2012/france_nuke_cuts
Pretty terrible situation. Looks like they’re going to have to set up a permanent freeze wall.
grlcowan- how is one to guarantee that no further transient fission can occur in an uncontrolled and unknown configuration of molten core in an unknown state? I find it difficult to believe in guarantees under those circumstances. On the other hand-
This quote is from early in the disaster, so no steam explosion can happen now because temperatures are far too low. –
-Masah Goto former nuclear design engineer at Toshiba.
” He said a full core meltdown could also set off a fresh nuclear chain reaction, much like the one that occurred in 1999 at Japan’s Tokai processing plant. ”
“It could trigger the resumption of criticality,” Goto said.
http://www.nbcnews.com/science/if-theres-meltdown-then-what-6C10403315
So no, I am not quoting bad guys. Let’s talk facts, not personalities, please. You seem to confirm the possibility of transient fission in pockets and that the purpose of the water and boric acid is to prevent that possibility.
Even Tepco itself admits that the reactor may have undergone recriticality:
http://ajw.asahi.com/article/0311disaster/fukushima/AJ2011110216361
Its a little late for a discussion of the possibility of recriticality and illustrates the ridiculousness of the notion of cold shutdown. Its a term that only refers to undamaged reactors that are cooled to a safe level where no danger exists. That can hardly apply to the situation with three melted cores of unknown status.
“Recall that no dense pile of natural uranium, nor of low-enriched uranium, can support fission, even if it fills all space.”
And yet just such a natural pile of uranium did happen.
http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor
One of the things that can cause criticality to happen is the presence of a neutron reflector. This can be “graphite, beryllium, steel, tungsten carbide, or other materials”
Wikipedia
Look up criticality accident from the same source and you will find that Otto Frisch got dosed with radiation when his own body apparently reflected enough neutrons
“Otto Frisch received a larger than intended dose of radiation in 1954, when leaning over the Lady Godiva device for a couple of seconds. He noticed that the red lamps that flickered intermittently when neutrons were being emitted were ‘glowing continuously’. Frisch’s body had reflected some neutrons back to the device, causing it to go critical”
So no, I do not think occasional criticality of that nature can be ruled out. Since Tepco believes its possible, I think we can consider it a real possibility.
Where’s joffran (or however it’s spelled) at? Usually he has something to add about the safety of nuke plants.
You see the two thumbs down? They got nothing to say.