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Fukushima Update April 8
First the good news. Yesterdays 7.4 quake appears to have not created any serious damage at any other nuclear plant though some had to go to emergency power supply because of loss of external power. It is unknown if additional damage occurred at the Daiichi plant.
The Japanese regulator NISA admitted to the possibility that the molten core of reactor no 2 leaked from the reactor pressure vessel into the primary containment. Due to some earlier damage that containment has leaks to the environment.
Speaking to the NYT U.S. sources have several even more alarming suspicions of further damage at the other reactors:
[S]ome of the radiation readings at Reactors Nos. 1 and 3 over the last week were nearly as high as or higher than the 3,300 rems per hour that the commission said it was trying to explain, so it would appear that the speculation would apply to them as well. At No. 2, extremely radioactive material continues to ooze out of the reactor pressure vessel, and the leak is likely to widen with time, a western nuclear executive asserted.
[…]
Flashes of extremely intense radioactivity have become a serious problem, he said. Tokyo Electric’s difficulties in providing accurate information on radiation are not a result of software problems, as some Japanese officials have suggested, but stem from damage to measurement instruments caused by radiation, the executive said.
Broken pieces of fuel rods have been found outside of Reactor No. 2, and are now being covered with bulldozers, he said. The pieces may be from rods in the spent-fuel pools that were flung out by hydrogen explosions.
The above includes several alarming points I have not seen reported so far:
- 3,300 REM/hour are 33 Sievert/hour. Anything above 10 Sievert means immediate death for those exposed to it. It is the first time I see such a high estimate.
- Nuclear fuel being exposed in the surrounding of the plant is also new.
- While we have feared that some continued spontaneous fission might occur in pockets of the molten cores the “flashes of extremely intense radioactivity” appear to confirm such reactions.
- It seems that the Japanese have limited all their equipment to just measure up to 1 Sievert. Several readings they had were reported as “above 1,000 milliSievert” which in reality can be anything higher. The German nuclear emergency team has instruments that can measure up to 200,000 Gray (~Sievert) per hour plus the robots needed to use them. Why ain’t these things in Japan?
The information from Japan is still scarce. The regulator NISA has as of now no updates for yesterday or today. The industry site JAIF has some newer information but that is only rudimentary. The reactor owner TEPCO does not put out more information either. All this seems to be inconsistent with the Convention on Early Notification of a Nuclear Accident which requires analyzable data to be made available. The Japanese government is blaming foreign news media of exaggerating the issue and wants it embassies to correct them. It may be that some media are exaggerating. But the best way to fight misinformation is to provide timely and complete information. That has not been done so far.
Nitrogen has been pumped into the primary containment vessel (PCV, drywell) to prevent a possible hydrogen explosion there. By that Tepco finally admitted the obvious. That somehow hydrogen is escaping from a leaky reactor pressure vessel into the PVC.
The level of highly radioactive water in a pipe trench has increased by five centimeter and is now less then one meter from overflow. This after an obvious leak to the ocean was stopped. It is likely that there more leaks to sea though.
I find it difficult to believe that a closed water cooling cycle can be reestablished for the three reactors. But continuing the current “feed and bleed” procedure will increase the release of highly radioactive water to the environment. Other means of “cooling” like simply covering the cores with sand/boron/lead, will have to be introduced.
Toshiba and its subsidiary Westinghouse Electric are planing to dismantle the ruined reactors. They envision big bags of greenbacks flowing towards them. Forgetaboutit. These reactors will likely get entombed, not dismantled.
Additional resources:
All Things Nuclear – blog by the Union of Concerned Scientists
Atomic power review – blog
Arms Control Wonk – blog
Brave New Climate – pro nuclear blog
Bulletin of the Atomic Scientists
Digital Globe Sat Pictures
IAEA
NISA Japan’s Nuclear Regulator
Japan Atomic Industrial Forum (regular updates)
Japanese government press releases in English
Tepco press releases in English
Kyodo News Agency
Asahi Shimbun leading Japanese newspaper in English
NHK World TV – Live stream
Status reports in German for the German Federal Government by the GfR
Just a note on ASKOD’s statement “if we keep spewing radioactive waste into different ecosystems, maybe there are tipping points we do not know about yet”.
I live with the pacific all around me. The name of this stunning body of water once said it all but the actions of the whitefellas who live thousands of kilometers away from the Pacific:
pa·cif·ic
/p?’s?f?k/ Show Spelled[puh-sif-ik] Show IPA
–adjective
1.
tending to make or preserve peace; conciliatory: pacific overtures.
2.
not warlike; peaceable; mild: a pacific disposition.
3.
at peace; peaceful: a pacific era in history.
4.
calm; tranquil: The Wabash is a pacific river.
It’s once proud name has been grossly perverted.
As I wrote upthread english amerikan and french desecration of an area where no nations that are actually located in the Pacific have nuclear weapons, and who have striven to resolve differences peacefully has been legion.
Some of you may have heard of Ciguatera fish poisoning. Most of the people of the pacific regard seafood as their main source of protein and until the vacuum cleaning of the oceans, the only issue with seafood was Ciguatera fish poisoning. It is caused by a human eating a fish that has been eating coral when particular algae are blooming near the coral. The algae contains a toxin which becomes concentrated as it moves up the food chain.
Here is how wikipedia describes it:
Ciguatera is a foodborne illness caused by eating certain reef fishes whose flesh is contaminated with toxins originally produced by dinoflagellates such as Gambierdiscus toxicus which lives in tropical and subtropical waters. These dinoflagellates adhere to coral, algae and seaweed, where they are eaten by herbivorous fish who in turn are eaten by larger carnivorous fish. In this way the toxins move up the food chain and bio accumulate. Gambierdiscus toxicus is the primary dinoflagellate responsible for the production of a number of similar toxins that cause ciguatera. These toxins include ciguatoxin, maitotoxin, scaritoxin and palytoxin. Predator species near the top of the food chain in tropical and subtropical waters, such as barracudas, snapper, moray eels, parrotfishes, groupers, triggerfishes and amberjacks, are most likely to cause ciguatera poisoning, although many other species cause occasional outbreaks of toxicity. Ciguatoxin is very heat-resistant, so ciguatoxin-laden fish cannot be detoxified by conventional cooking
That article goes on to say that some anthropologists believe that the Polynesian migrations across the Pacific were caused by the Ciguatera outbreaks which resulted from “cooling climatic conditions” from 1000 to 1400. (1400 is about the time tangata whenua [Maori] arrived in NZ.)
Although there has been some description of the mechanism by which falling ocean temperatures can cause increased toxic algae bloom no one has yet been able to describe the mechanism which caused the phenomenon I found reported in an article titled Environmental Effects of French Nuclear Testing
A review of the epidemiology of ciguatera in French Polynesia from 1960 to 1984 clearly demonstrates a general flare-up in ciguatera, with more than 24,000 cases among a population that grew from 84,500 in 1962 to 174,000 by mid1985. The incidence rose dramatically through the 1960s, peaking from 1972 to 1975 at 1,200 per 100,000, a tenfold increase over the 1960 figure.(39) Some of this increase may be due to improved case reporting, but this has never been presented as a major reason for the increase. In the areas most affected, the eastern Tuamotu, Gambier, and Marquesas Archipelagos, the incidence in the 1980s remains at high levels.
The most important cause of ciguatera outbreaks is the disturbance of the sensitive ecology of the coral reef. Natural events, such as storms, earthquakes and tidal waves, can disturb reef ecology, as can human activities. Nuclear test explosions and the construction of supporting infrastructures have been linked with ciguatera outbreaks.(40) For example, the Tuamotu Archipelago was more or less free of ciguatera before the early 1960’s. Epidemiological studies show that in parallel with the installation and running of the test facilities, repeated outbreaks occurred. This is the case for the Hao Atoll (staging base for the testing since 1965, first ciguatera outbreak in 1966), the Gambier Islands (construction of military facilities in 1967, first outbreak in 1968) and Moruroa Atoll (highest density of Gambierdiscus toxicus after the Gambier Islands in 1981 )
The article goes on to state “A study by the US Atomic Energy Commission showed no correlation between radioactivity and ciguatoxicity in fish.(42) It is most likely that ancillary military activities linked to the nuclear testing facilities, like runway construction, waste dumping, ship decontamination, are causing ciguatoxicity by disturbance of reef ecology.”
I regard any study by the Atomic Energy Commission as suspect, but unfortunately this is the loophole which allows so much pollution. It isn’t enough to show that an increase in presence of a substance has been accompanied by an equivalent increase in a particular cancer or other disease – unless there is a proven causal relationship, the polluters are usually allowed to continue poisoning people until such a mechanism has been established. Wouldn’t it be smarter to err on the side of caution? What and have the rich risk some of their ill gotten gains – I don’t think so. The Atomic Energy Commission cannot provide any mechanism which describes how construction may have caused the increase, yet they criticise those who point the finger at radioactive fallout for their failure to do the same.
Just as the toxin from algae became concentrated when a bigger animal ate many smaller animals each of whom had ingested some of the algae, then an even bigger predator ate many of those animals, the same happens with radioactivity.
Dumping it in the ocean won’t disperse or dilute it – once it enters a bio-system it will become concentrated. Now I don’t know if radioactive salts in water cause Ciguatera poisoning, but the commission’s findings appear flawed to me.
Why didn’t they show an increase in Ciguatera with non nuclear construction? From reading these articles it seems only nuclear building sites had this issue. If that is the case it makes the AEC contention downright ludicrous. There are areas of the pacific that have been subjected to massive tourism development, did those areas also show increases of Ciguatera poisoning? If they did why weren’t those incidents used to prove radioactivity’s innocence?
It is as ASKOD wrote “there are tipping points we do not know about yet”.
Not content with wrecking our environment last century with their war machines, now they cause the same sort of pollution into the Pacific off japan. Japenese people turned out in their millions to protest against atomic energy generation, way back in the 1950’s, they were ignored by the administration put in to Japan after ww2, back when usaid was one of the main weapons of amerikan imperialism. General Electric designed teh POS leaking into our oceans, whadda surprise!
This is bad shit and it really pisses me off that it is happening in my backyard not around france england and amerika the mob who began nuclear testing and nuclear power generation- those pricks have wrecked their environments anyway, they have no business despoiling ours just cause we’ve got a higher concentration of brownfellas and a lower concentration of whitefellas than france england and amerika. Because when you boil this down, that is the real reason this has occurred. The pointy heads didn’t empathise with unwhite cultures and consequently failed to think thru the consequences of failure.
Posted by: Debs is dead | Apr 9 2011 6:46 utc | 14
Why I am not worried about Japan’s nuclear reactors.
| Morgsatlarge – blogorific. from morgsatlarge.wordpress.com
[JEREMIAH: The original post has since been removed(!), but I felt worth reposting as my GReader retained a copy of the original text.]
I am writing this text (Mar 12) to give you some peace of mind regarding some of the troubles in Japan, that is the safety of Japan’s nuclear reactors. Up front, the situation is serious, but under control. And this text is long! But you will know more about nuclear power plants after reading it than all journalists on this planet put together.
There was and will *not* be any significant release of radioactivity.
By “significant” I mean a level of radiation of more than what you would receive on – say – a long distance flight, or drinking a glass of beer that comes from certain areas with high levels of natural background radiation.
I have been reading every news release on the incident since the earthquake. There has not been one single (!) report that was accurate and free of errors (and part of that problem is also a weakness in the Japanese crisis communication). By “not free of errors” I do not refer to tendentious anti-nuclear journalism – that is quite normal these days. By “not free of errors” I mean blatant errors regarding physics and natural law, as well as gross misinterpretation of facts, due to an obvious lack of fundamental and basic understanding of the way nuclear reactors are build and operated. I have read a 3 page report on CNN where every single paragraph contained an error.
We will have to cover some fundamentals, before we get into what is going on.
Construction of the Fukushima nuclear power plants
The plants at Fukushima are so called Boiling Water Reactors, or BWR for short. Boiling Water Reactors are similar to a pressure cooker. The nuclear fuel heats water, the water boils and creates steam, the steam then drives turbines that create the electricity, and the steam is then cooled and condensed back to water, and the water send back to be heated by the nuclear fuel. The pressure cooker operates at about 250 °C.
The nuclear fuel is uranium oxide. Uranium oxide is a ceramic with a very high melting point of about 3000 °C. The fuel is manufactured in pellets (think little cylinders the size of Lego bricks). Those pieces are then put into a long tube made of Zircaloy with a melting point of 2200 °C, and sealed tight. The assembly is called a fuel rod. These fuel rods are then put together to form larger packages, and a number of these packages are then put into the reactor. All these packages together are referred to as “the core”.
The Zircaloy casing is the first containment. It separates the radioactive fuel from the rest of the world.
The core is then placed in the “pressure vessels”. That is the pressure cooker we talked about before. The pressure vessels is the second containment. This is one sturdy piece of a pot, designed to safely contain the core for temperatures several hundred °C. That covers the scenarios where cooling can be restored at some point.
The entire “hardware” of the nuclear reactor – the pressure vessel and all pipes, pumps, coolant (water) reserves, are then encased in the third containment. The third containment is a hermetically (air tight) sealed, very thick bubble of the strongest steel. The third containment is designed, built and tested for one single purpose: To contain, indefinitely, a complete core meltdown. For that purpose, a large and thick concrete basin is cast under the pressure vessel (the second containment), which is filled with graphite, all inside the third containment. This is the so-called “core catcher”. If the core melts and the pressure vessel bursts (and eventually melts), it will catch the molten fuel and everything else. It is built in such a way that the nuclear fuel will be spread out, so it can cool down.
This third containment is then surrounded by the reactor building. The reactor building is an outer shell that is supposed to keep the weather out, but nothing in. (this is the part that was damaged in the explosion, but more to that later).
Fundamentals of nuclear reactions
The uranium fuel generates heat by nuclear fission. Big uranium atoms are split into smaller atoms. That generates heat plus neutrons (one of the particles that forms an atom). When the neutron hits another uranium atom, that splits, generating more neutrons and so on. That is called the nuclear chain reaction.
Now, just packing a lot of fuel rods next to each other would quickly lead to overheating and after about 45 minutes to a melting of the fuel rods. It is worth mentioning at this point that the nuclear fuel in a reactor can *never* cause a nuclear explosion the type of a nuclear bomb. Building a nuclear bomb is actually quite difficult (ask Iran). In Chernobyl, the explosion was caused by excessive pressure buildup, hydrogen explosion and rupture of all containments, propelling molten core material into the environment (a “dirty bomb”). Why that did not and will not happen in Japan, further below.
In order to control the nuclear chain reaction, the reactor operators use so-called “moderator rods”. The moderator rods absorb the neutrons and kill the chain reaction instantaneously. A nuclear reactor is built in such a way, that when operating normally, you take out all the moderator rods. The coolant water then takes away the heat (and converts it into steam and electricity) at the same rate as the core produces it. And you have a lot of leeway around the standard operating point of 250°C.
The challenge is that after inserting the rods and stopping the chain reaction, the core still keeps producing heat. The uranium “stopped” the chain reaction. But a number of intermediate radioactive elements are created by the uranium during its fission process, most notably Cesium and Iodine isotopes, i.e. radioactive versions of these elements that will eventually split up into smaller atoms and not be radioactive anymore. Those elements keep decaying and producing heat. Because they are not regenerated any longer from the uranium (the uranium stopped decaying after the moderator rods were put in), they get less and less, and so the core cools down over a matter of days, until those intermediate radioactive elements are used up.
This residual heat is causing the headaches right now.
So the first “type” of radioactive material is the uranium in the fuel rods, plus the intermediate radioactive elements that the uranium splits into, also inside the fuel rod (Cesium and Iodine).
There is a second type of radioactive material created, outside the fuel rods. The big main difference up front: Those radioactive materials have a very short half-life, that means that they decay very fast and split into non-radioactive materials. By fast I mean seconds. So if these radioactive materials are released into the environment, yes, radioactivity was released, but no, it is not dangerous, at all. Why? By the time you spelled “R-A-D-I-O-N-U-C-L-I-D-E”, they will be harmless, because they will have split up into non radioactive elements. Those radioactive elements are N-16, the radioactive isotope (or version) of nitrogen (air). The others are noble gases such as Xenon. But where do they come from? When the uranium splits, it generates a neutron (see above). Most of these neutrons will hit other uranium atoms and keep the nuclear chain reaction going. But some will leave the fuel rod and hit the water molecules, or the air that is in the water. Then, a non-radioactive element can “capture” the neutron. It becomes radioactive. As described above, it will quickly (seconds) get rid again of the neutron to return to its former beautiful self.
This second “type” of radiation is very important when we talk about the radioactivity being released into the environment later on.
What happened at Fukushima
I will try to summarize the main facts. The earthquake that hit Japan was 7 times more powerful than the worst earthquake the nuclear power plant was built for (the Richter scale works logarithmically; the difference between the 8.2 that the plants were built for and the 8.9 that happened is 7 times, not 0.7). So the first hooray for Japanese engineering, everything held up.
When the earthquake hit with 8.9, the nuclear reactors all went into automatic shutdown. Within seconds after the earthquake started, the moderator rods had been inserted into the core and nuclear chain reaction of the uranium stopped. Now, the cooling system has to carry away the residual heat. The residual heat load is about 3% of the heat load under normal operating conditions.
The earthquake destroyed the external power supply of the nuclear reactor. That is one of the most serious accidents for a nuclear power plant, and accordingly, a “plant black out” receives a lot of attention when designing backup systems. The power is needed to keep the coolant pumps working. Since the power plant had been shut down, it cannot produce any electricity by itself any more.
Things were going well for an hour. One set of multiple sets of emergency Diesel power generators kicked in and provided the electricity that was needed. Then the Tsunami came, much bigger than people had expected when building the power plant (see above, factor 7). The tsunami took out all multiple sets of backup Diesel generators.
When designing a nuclear power plant, engineers follow a philosophy called “Defense of Depth”. That means that you first build everything to withstand the worst catastrophe you can imagine, and then design the plant in such a way that it can still handle one system failure (that you thought could never happen) after the other. A tsunami taking out all backup power in one swift strike is such a scenario. The last line of defense is putting everything into the third containment (see above), that will keep everything, whatever the mess, moderator rods in our out, core molten or not, inside the reactor.
When the diesel generators were gone, the reactor operators switched to emergency battery power. The batteries were designed as one of the backups to the backups, to provide power for cooling the core for 8 hours. And they did.
Within the 8 hours, another power source had to be found and connected to the power plant. The power grid was down due to the earthquake. The diesel generators were destroyed by the tsunami. So mobile diesel generators were trucked in.
This is where things started to go seriously wrong. The external power generators could not be connected to the power plant (the plugs did not fit). So after the batteries ran out, the residual heat could not be carried away any more.
At this point the plant operators begin to follow emergency procedures that are in place for a “loss of cooling event”. It is again a step along the “Depth of Defense” lines. The power to the cooling systems should never have failed completely, but it did, so they “retreat” to the next line of defense. All of this, however shocking it seems to us, is part of the day-to-day training you go through as an operator, right through to managing a core meltdown.
It was at this stage that people started to talk about core meltdown. Because at the end of the day, if cooling cannot be restored, the core will eventually melt (after hours or days), and the last line of defense, the core catcher and third containment, would come into play.
But the goal at this stage was to manage the core while it was heating up, and ensure that the first containment (the Zircaloy tubes that contains the nuclear fuel), as well as the second containment (our pressure cooker) remain intact and operational for as long as possible, to give the engineers time to fix the cooling systems.
Because cooling the core is such a big deal, the reactor has a number of cooling systems, each in multiple versions (the reactor water cleanup system, the decay heat removal, the reactor core isolating cooling, the standby liquid cooling system, and the emergency core cooling system). Which one failed when or did not fail is not clear at this point in time.
So imagine our pressure cooker on the stove, heat on low, but on. The operators use whatever cooling system capacity they have to get rid of as much heat as possible, but the pressure starts building up. The priority now is to maintain integrity of the first containment (keep temperature of the fuel rods below 2200°C), as well as the second containment, the pressure cooker. In order to maintain integrity of the pressure cooker (the second containment), the pressure has to be released from time to time. Because the ability to do that in an emergency is so important, the reactor has 11 pressure release valves. The operators now started venting steam from time to time to control the pressure. The temperature at this stage was about 550°C.
This is when the reports about “radiation leakage” starting coming in. I believe I explained above why venting the steam is theoretically the same as releasing radiation into the environment, but why it was and is not dangerous. The radioactive nitrogen as well as the noble gases do not pose a threat to human health.
At some stage during this venting, the explosion occurred. The explosion took place outside of the third containment (our “last line of defense”), and the reactor building. Remember that the reactor building has no function in keeping the radioactivity contained. It is not entirely clear yet what has happened, but this is the likely scenario: The operators decided to vent the steam from the pressure vessel not directly into the environment, but into the space between the third containment and the reactor building (to give the radioactivity in the steam more time to subside). The problem is that at the high temperatures that the core had reached at this stage, water molecules can “disassociate” into oxygen and hydrogen – an explosive mixture. And it did explode, outside the third containment, damaging the reactor building around. It was that sort of explosion, but inside the pressure vessel (because it was badly designed and not managed properly by the operators) that lead to the explosion of Chernobyl. This was never a risk at Fukushima. The problem of hydrogen-oxygen formation is one of the biggies when you design a power plant (if you are not Soviet, that is), so the reactor is build and operated in a way it cannot happen inside the containment. It happened outside, which was not intended but a possible scenario and OK, because it did not pose a risk for the containment.
So the pressure was under control, as steam was vented. Now, if you keep boiling your pot, the problem is that the water level will keep falling and falling. The core is covered by several meters of water in order to allow for some time to pass (hours, days) before it gets exposed. Once the rods start to be exposed at the top, the exposed parts will reach the critical temperature of 2200 °C after about 45 minutes. This is when the first containment, the Zircaloy tube, would fail.
And this started to happen. The cooling could not be restored before there was some (very limited, but still) damage to the casing of some of the fuel. The nuclear material itself was still intact, but the surrounding Zircaloy shell had started melting. What happened now is that some of the byproducts of the uranium decay – radioactive Cesium and Iodine – started to mix with the steam. The big problem, uranium, was still under control, because the uranium oxide rods were good until 3000 °C. It is confirmed that a very small amount of Cesium and Iodine was measured in the steam that was released into the atmosphere.
It seems this was the “go signal” for a major plan B. The small amounts of Cesium that were measured told the operators that the first containment on one of the rods somewhere was about to give. The Plan A had been to restore one of the regular cooling systems to the core. Why that failed is unclear. One plausible explanation is that the tsunami also took away / polluted all the clean water needed for the regular cooling systems.
The water used in the cooling system is very clean, demineralized (like distilled) water. The reason to use pure water is the above mentioned activation by the neutrons from the Uranium: Pure water does not get activated much, so stays practically radioactive-free. Dirt or salt in the water will absorb the neutrons quicker, becoming more radioactive. This has no effect whatsoever on the core – it does not care what it is cooled by. But it makes life more difficult for the operators and mechanics when they have to deal with activated (i.e. slightly radioactive) water.
But Plan A had failed – cooling systems down or additional clean water unavailable – so Plan B came into effect. This is what it looks like happened:
In order to prevent a core meltdown, the operators started to use sea water to cool the core. I am not quite sure if they flooded our pressure cooker with it (the second containment), or if they flooded the third containment, immersing the pressure cooker. But that is not relevant for us.
The point is that the nuclear fuel has now been cooled down. Because the chain reaction has been stopped a long time ago, there is only very little residual heat being produced now. The large amount of cooling water that has been used is sufficient to take up that heat. Because it is a lot of water, the core does not produce sufficient heat any more to produce any significant pressure. Also, boric acid has been added to the seawater. Boric acid is “liquid control rod”. Whatever decay is still going on, the Boron will capture the neutrons and further speed up the cooling down of the core.
The plant came close to a core meltdown. Here is the worst-case scenario that was avoided: If the seawater could not have been used for treatment, the operators would have continued to vent the water steam to avoid pressure buildup. The third containment would then have been completely sealed to allow the core meltdown to happen without releasing radioactive material. After the meltdown, there would have been a waiting period for the intermediate radioactive materials to decay inside the reactor, and all radioactive particles to settle on a surface inside the containment. The cooling system would have been restored eventually, and the molten core cooled to a manageable temperature. The containment would have been cleaned up on the inside. Then a messy job of removing the molten core from the containment would have begun, packing the (now solid again) fuel bit by bit into transportation containers to be shipped to processing plants. Depending on the damage, the block of the plant would then either be repaired or dismantled.
Now, where does that leave us?
The plant is safe now and will stay safe.
Japan is looking at an INES Level 4 Accident: Nuclear accident with local consequences. That is bad for the company that owns the plant, but not for anyone else.
Some radiation was released when the pressure vessel was vented. All radioactive isotopes from the activated steam have gone (decayed). A very small amount of Cesium was released, as well as Iodine. If you were sitting on top of the plants’ chimney when they were venting, you should probably give up smoking to return to your former life expectancy. The Cesium and Iodine isotopes were carried out to the sea and will never be seen again.
There was some limited damage to the first containment. That means that some amounts of radioactive Cesium and Iodine will also be released into the cooling water, but no Uranium or other nasty stuff (the Uranium oxide does not “dissolve” in the water). There are facilities for treating the cooling water inside the third containment. The radioactive Cesium and Iodine will be removed there and eventually stored as radioactive waste in terminal storage.
The seawater used as cooling water will be activated to some degree. Because the control rods are fully inserted, the Uranium chain reaction is not happening. That means the “main” nuclear reaction is not happening, thus not contributing to the activation. The intermediate radioactive materials (Cesium and Iodine) are also almost gone at this stage, because the Uranium decay was stopped a long time ago. This further reduces the activation. The bottom line is that there will be some low level of activation of the seawater, which will also be removed by the treatment facilities.
The seawater will then be replaced over time with the “normal” cooling water
The reactor core will then be dismantled and transported to a processing facility, just like during a regular fuel change.
Fuel rods and the entire plant will be checked for potential damage. This will take about 4-5 years.
The safety systems on all Japanese plants will be upgraded to withstand a 9.0 earthquake and tsunami (or worse)
I believe the most significant problem will be a prolonged power shortage. About half of Japan’s nuclear reactors will probably have to be inspected, reducing the nation’s power generating capacity by 15%. This will probably be covered by running gas power plants that are usually only used for peak loads to cover some of the base load as well. That will increase your electricity bill, as well as lead to potential power shortages during peak demand, in Japan.
If you want to stay informed, please forget the usual media outlets and consult the following websites:
http://www.world-nuclear-news.org/RS_Battle_to_stabilise_earthquake_reactors_1203111.html
http://bravenewclimate.com/2011/03/12/japan-nuclear-earthquake/
“>http://ansnuclearcafe.org/2011/03/11/media-updates-on-nuclear-power-stations-in-japan/
Ahhhh hindsight….
Posted by: Jeremiah | Apr 9 2011 23:14 utc | 26
Meanwhile, back at the ranch… (reality check)
Since the March 11 earthquake that ravaged northern Japan, workers at Fukushima Daiichi have been struggling to cool down three overheated reactors and keep pools of spent but still potent nuclear fuel from spreading further radioactive contamination across northern Japan.
A month into the crisis, the utility acknowledges, there is no end in sight.
The problems are so far “beyond the design capacity” of the plant that the Japanese are working in uncharted territory, said Michael Friedlander, a former senior operator at U.S. nuclear power plants.
“No nuclear power plant has ever considered the inability to get on long-term core cooling for more than a week, much less three weeks,” Friedlander said.
Some Japanese experts now say the effort is in danger of failing unless Japan seeks more help from international experts to bring it to an end. Tetsunari Iida, an engineer-turned-industry critic, said the situation is “beyond the reach” of Japan’s closely knit nuclear establishment.
“A real exit strategy has to start with an inspection by the world’s top experts on nuclear accidents,” Iida told reporters at Japan’s national press club last week.
Engineers and workers so far have managed to stave off a complete meltdown in Fukushima Daiichi’s reactors 1-3 and in the spent fuel pool of unit 4. But experts say the overheated fuel rods are likely to have suffered extensive damage, and there is a complication for seemingly every advance.
Much of the past week was dominated by the attempt to stop water laced with massive amounts of radioactive particles from pouring into the Pacific Ocean — water that comes out of the reactors “screaming with radioactivity,” Friedlander said. Tokyo Electric is now grappling with where to put the stuff, even dumping thousands of tons of less-radioactive water into the Pacific to make room for it in a reservoir for low-level waste.
In a normally functioning plant, coolant water is circulated out of the reactors and chilled. Then it’s pumped back in to carry more heat away from the plant’s fuel rods, which continue producing energy long after the chain reaction at the heart of the units has been stopped.
“You have to get the recirculation system up and functioning so they can cool that water in the normal way,” said Gary Was, a nuclear engineering professor at the University of Michigan and a CNN consultant. Normal cooling systems don’t require the massive amounts of water — around 7 metric tons (1,850 gallons) per hour — now being poured into the reactors.
“That’s a big problem,” Was said.
Tokyo Electric officials told CNN they can’t say when they’ll be able to restore those normal cooling. The first step is to get highly radioactive water out of the flooded basements of the units’ turbine plants, then figure out how badly the equipment inside has been damaged.
For the first two weeks of the crisis, engineers pumped seawater into the reactors. But the resulting buildup of salt inside has made it harder for coolant to circulate, U.S. nuclear safety officials advised in March.
In addition, Was said, the fuel rods are likely in a state of “partial melt,” the extent of which will be difficult to determine. After 1979’s Three Mile Island accident in Pennsylvania, it took more than two years before operators were able to get a camera into the reactor to examine its condition, he said.
Satoshi Sato, a Japanese nuclear industry consultant, called the current line of attack a “waste of effort.” Plant instruments are likely damaged and unreliable because of the intense heat that was generated, and pumping more water into the reactors is only making the contamination problem worse, he said.
“There is no happy end with their approach,” Sato told CNN. “They must change the approach. That’s something I’m sure of 100 percent.”
After the 1986 Chernobyl accident, the world’s worst to date, the Soviet Union encased the plant’s damaged reactor in a massive concrete sarcophagus. Iida said Fukushima Daiichi’s reactors remain too hot to pour concrete, but he suggested pouring a slurry of minerals and sand over them to carry away heat before encasing them.
BTW re #26 “The Cesium and Iodine isotopes were carried out to the sea and will never be seen again…” ‘Tis verra sorry I am indeed, to say unkind things about the original author (not Jeremiah), but this is utter and pernicious rubbish. (PDF:) Cesium bio-accumulative in marine food chain. This flat-earth-grade idea, that dumping stuff into the sea means All Gone No Problemo [out of sight out of mind, and we’re definitely out of our minds on this one] — is why we have a floating island of plastic trash 1 or 2 times the size of Texas (it varies) slowly spinning in the North Pacific Gyre.
Some of these long-lasting plastics end up in the stomachs of marine birds and animals, and their young,[9] including sea turtles and the Black-footed Albatross.[29] Besides the particles’ danger to wildlife, the floating debris can absorb organic pollutants from seawater, including PCBs, DDT, and PAHs.[30] Aside from toxic effects,[31] when ingested, some of these are mistaken by the endocrine system as estradiol, causing hormone disruption in the affected animal.[29] These toxin-containing plastic pieces are also eaten by jellyfish, which are then eaten by larger fish. Many of these fish are then consumed by humans, resulting in their ingestion of toxic chemicals.[32] Marine plastics also facilitate the spread of invasive species that attach to floating plastic in one region and drift long distances to colonize other ecosystems.[19]
Research has shown that this plastic marine debris affects at least 267 species worldwide and a few of the 267 species reside in the North Pacific Gyre.[33]
So, the radioactive fine particulates, slurry, etc. entering the ocean as the Fukushima debacle grinds on: they do not just go away to “never be seen again.” They bioaccumulate in the food chain (cesium’s first half-life takes 30 years or so). Fish will be eating fish that have eaten fish that have eaten various marine critters that ingested the cesium particles; and eventually (even if humans are the only kind of critter you care about, time to start listening now) humans will eat fish from higher up on that food chain with bioaccumulated cesium in their flesh.
Someone (I forget which forum) said that finding “safe” places to site nuke plants was kinda like cordoning off one corner of the swimming pool for pissing in. Very quotable, and I couldn’t agree more. We’ve known for decades now that this is one, count it, one planet, one massive chaotic weather system, one huge world-girdling ocean (we give different parts of it different names but that’s our fantasy, just like we pretend that some trees in the boreal forest are “Canadian” and some are “American.” The trees don’t know or care. The isotopes travelling with ocean currents and storm systems don’t know that they’re Japanese and not supposed to be “serious” for people of other nationalities. We know by now that the salmon are the forest/rivers and the forest/rivers are the salmon, though we’re trying really hard to ignore that knowledge because internalising it would force us to reduce profit-taking by means of mining-style resource liquidation. And we should know better than to say deeply stupid things like “just chuck it into the ocean and it stops being a problem.” As a toxic waste management strategy that’s in the Ostrich class: if I stick my head in the sand then what I can’t see can’t hurt me.
Criminy. Gotta go do something else and cool off a bit before I lose it completely and hit the caps-lock key.
Posted by: DeAnander | Apr 11 2011 4:44 utc | 29
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