BOILING-WATER REACTOR SYSTEM: The system's inverted lightbulb primary containment vents below through pipes to a pressure-suppression torus. Once that torus breaches due to overpressure, the secondary containment is all that separates the released radioactive steam from the outside environment.
Image: http://www.nucleartourist.com/
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First came the earthquake, centered just off Japan's east coast, near Honshu. The added horror of the tsunami quickly followed. Now the world waits as emergency crews attempt to stop a core meltdown from occurring at the Fukushima Daichi nuclear reactor, already the site of an explosion of the reactor's housing structure.
At 1:30 P.M. Eastern Standard Time on March 12, American nuclear experts gathered for a call-in media briefing. Whereas various participants discussed the policy ramifications of the crisis, physicist Ken Bergeron provided most of the information regarding the actual damage to the reactor.
"Reactor analysts like to categorize potential reactor accidents into groups," said Bergeron, who did research on nuclear reactor accident simulation at Sandia National Laboratories in New Mexico. "And the type of accident that is occurring in Japan is known as a station blackout. It means loss of off-site AC power—power lines are down—and then a subsequent failure of emergency power on-site—the diesel generators. It is considered to be extremely unlikely, but the station blackout has been one of the great concerns for decades.
"The probability of this occurring is hard to calculate, primarily because of the possibility of what are called common-cause accidents, where the loss of off-site power and of on-site power are caused by the same thing. In this case it was the earthquake and tsunami. So we're in uncharted territory, we're in a land where probability says we shouldn't be. And we're hoping that all of the barriers to release of radioactivity will not fail."
Bergeron explained the basics of overheating at a nuclear fission plant. "The fuel rods are long uranium rods clad in a [zirconium alloy casing]. They're held in a cylindrical-shaped array. And the water covers all of that. If the water descends below the level of the fuel, then the temperature starts going up and the cladding bursts, releasing a lot of fission products. And eventually the core just starts slumping and melting. Quite a bit of this happened in TMI [Three Mile Island in Pennsylvania], but the pressure vessel did not fail."
Former U.S. Nuclear Regulatory Commission (NRC) member Peter Bradford added, "The other thing that happens is that the cladding, which is just the outside of the tube, at a high enough temperature interacts with the water. It's essentially a high-speed rusting, where the zirconium becomes zirconium oxide and the hydrogen is set free. And hydrogen at the right concentration in an atmosphere is either flammable or explosive."
"Hydrogen combustion would not occur necessarily in the containment building," Bergeron pointed out, "which is inert—it doesn't have any oxygen—but they have had to vent the containment, because this pressure is building up from all this steam. And so the hydrogen is being vented with the steam and it's entering some area, some building, where there is oxygen, and that's where the explosion took place."
Bergeron discussed the specific power plant in question, the General Electric design BWR Mark 1. "This is a boiling-water reactor. It's one of the first designs ever developed for commercial reactors in this country, and it's widely used in Japan as well. Compared to other reactors, if you look at NRC studies, according to calculations, it has a relatively low core-damage frequency. (That means the likelihood that portions of the fuel will melt.) And in part, that's because it has a larger variety of ways to get water into the core. So they have a lot of options, and they're using them now—using these steam-driven turbines, for example. There's no electricity required to run these steam-driven turbines. But they still need battery electricity to operate the valves and the controls.
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112 Comments
Add CommentThank you for a very informative and very timely article!
Reply | Report Abuse | Link to thiswe think it is not possible to use the turbines for cooling because they where blown away by the explosion.
Reply | Report Abuse | Link to thishttp://www.nucleartourist.com/type/bwr.htm
Reply | Report Abuse | Link to thisVery good article. The question I have is why can't one of the reactors be restarted to generate AC to feed the pumps for the other reactors (after disconnecting the system from the grid)? Does this now take too much time?
Reply | Report Abuse | Link to thisThanks very much for this. My question has been, in the worst case scenario, then what? This is of particular concern to me because I have family on the west coast of the US, so I've been trying to get a handle on this all day (I had training in handling radioisotopes in lab, so I understand the basics principles of exposure units and shielding).
Reply | Report Abuse | Link to thisIn the worst case, would the amount of radiation released by likely to reach the US, and if so, in what timeframe and at what levels? I would also love for a meteorologist to weigh in on this.
From the information I've been able to find from previous accidents, I expect that the levels would be low, and precautions would be minimal. All the same, coming up empty in terms of real data today, I just called family and asked them to plan indoor activities for the next few days, because from what I can tell, staying indoors should be adequate shielding from the increased but still low levels that would be expected. From my inferences with many unknowns and a lot of uncertainty.
Any insights on whether this is a real scenario to be concerned about?
I am sure that if they are having this much trouble with backup systems for cooling for reactors that are technically "turned off", then turning one unit fully back on under already difficult conditions and damage assessment would carry extreme risk.
Reply | Report Abuse | Link to thisI experienced Chernobyl In Germany and the effects on the West Coast would probably be similar in the worst case. I live in CA now so it's deja vu all over again.
Reply | Report Abuse | Link to thisThere were no direct effects on people, no problems being outdoors although daycare centers and similar kept kids inside as a precaution and all sand in sandboxes was replaced after a few days.
The main issue was food. There was no fresh meat, milk or produce for about two weeks until testing procedures were in place and fresh goods started to trickle into supermarkets again. That was the only significant effect I remember.
Thanks for that reply. I was looking at data from Chernobyl, and if what I read was accurate, it seems the highest exposure for a 24 hour period would have been ~2.4 mrems. An NRC document said public exposure should be limited to 2 mrems per *hour* and not more than 100 mrems per year, so if that was correct, the exposure was well under. From what I found, iodide isn't recommended until exposure is 25 mrems (over what time period, I'm not sure). But these numbers seem to indicate it was a very low exposure. So I'm really not very worried.
Reply | Report Abuse | Link to thisThat said, it's always recommended to limit any unnecessary exposure. So while I'm not overly worried, it's a very unobtrusive thing to choose a different day for a picnic, or decide not to dig in the garden.
Interesting choice of experts - a computer modeler and a lawyer whose primary claim to nuclear knowledge is that he was chosen via a political process to be a member of the Nuclear Regulatory Commission. While a commissioner, he was part of the team that spread a great deal of confusion in the aftermath of Three Mile Island because he did not really understand the technology, the chemistry or the physics of what was unfolding.
Reply | Report Abuse | Link to thisFor nparmalee, you have asked a reasonable question that deserves a reasonable answer. There is absolutely no reason for you to be concerned as a resident of the west coast of the United States. In fact, as long as you do not want to move your family inside the fence line at the affected plants, there is nothing for you to worry about with regard to the effects of the issues that the plants have experienced.
The technology is not "perfect" in that there have been challenges and equipment damage in the aftermath of the 5th worst earthquake ever recorded by humans. However, the technology is robust enough and the operators well trained enough so that essentially all of the radioactive materials will be contained within the boundaries of the primary containment structure. I do not expect that unit 1 at the Daiichi plant will ever operate again, but that is not much of a tragedy compared to all of the other capital equipment in Japan that will never again operate after the earthquake and tsunami. It is, after all, a 40 year old facility that has been helping to avoid burning fuel oil and natural gas for a very long time.
A very good source of concise information on the worst possible accident in a light water reactor licensed to standards that have been in effect since the late 1950s can be found in the 20 September 2002 issue of Science Magazine. You can find a PDF at the following URL
http://www.atomicinsights.com/pdf_files/SciencePaper-9.02.pdf
You can also learn more about the accident consequences from an operator's perspective at
http://atomicinsights.blogspot.com/2011/03/nuclear-plant-issues-in-japan-are-least.html
There has been at least partial melting at at least one of the plants, thus the cesium releases detected, and also confirmed by reports of water levels dropping and exposing the core.
Reply | Report Abuse | Link to thisPerhaps the worst bit of news and under-reported is that one of the troubled reactors is fueled with Uranium and Plutonium obtained from French reactors as recycled fuel.
The containment vessels in this family of reactors have a very high failure rate under stress, on the order of 90%.
They just granted these plants 40-year extensions last month(Fukushima).
Someone asked about fallout transit times to N. America; you're looking at 2-3 days Alaska, 3-5 days Washington State, 5-6 days most of California.
A useful non-governmental, non-industry site is Nuclear Information and Research dot org,(nirs.org)
They have a great fact-sheet on this family of GE Reactors too, and updates from Japanese correspondents(citizens).
"we're in a land where probability says we shouldn't be" huh?.... Expert....?
Reply | Report Abuse | Link to this@antonionio
Reply | Report Abuse | Link to thisThe Nuclear Information and Research Service is a great source of misinformation and antinuclear propaganda. It is not terribly good at keeping its web site up to date - the link from the front page to the "No New Nukes" campaign leads to a page that leads off as if the election of 2008 never happened.
"No New Nukes!
The Bush administration is the most aggressively pro-nuclear government since the days of Richard Nixon. From Vice-President Cheney’s secret Energy Task Force, which met with nuclear industry officials more than any other industry, to President Bush’s approval of the scientifically-indefensible Yucca Mountain high-level radioactive waste dump to its push to provide billions of taxpayer dollars to wealthy nuclear utilities, the Bush administration appears intent on rebuilding the nuclear power industry. Or, as we see it, creating a Nuclear Power Relapse.
Bush allies in Congress, led by Senate Energy Committee Ranking Member Pete Domenici (R-N.M.), have mounted repeated attempts to force taxpayer funding of new reactor construction, resulting in Congressional approval of $18.5 billion in loan guarantees in December 2007."
Yes, cesium as "been detected" at levels that are several orders of magnitude (powers of ten) below those that will cause negative human health effects. The professional, well trained operators are on the job and doing what they have been trained to do in some of the worst conditions imaginable. They shut down their reactor within minutes after the earthquake and began getting rid of decay heat right away.
The core at Daiichi unit 1 is probably damaged and the plant will most likely never restart. The use of sea water as the coolant is a good indicator that the plant operators recognized that fact. However, their actions to prevent an over pressurization of the containment structure by carefully monitored venting of some non condensible and slightly radioactive gases will ensure that no member of the public will be harmed.
The same cannot be said of the thousands of fossil fuel heated facilities that have been damaged, are now on fire, and whose toxic waste products are entering the environment without any controls or attention.
There is nothing to fear from the nuclear plants as long as you do not live inside the fence line.
BTW - what credentials do you or your quoted organization have that give you insight into the effects we are discussing?
I was the engineer officer of a nuclear submarine and the chemistry and radiological controls assistant on another one.
Seems to me the headline for this article should be changed; the article does not at all address what the worst case scenario might be. If the containment structure is breached in a meltdown, what happens then? Is is likely that hundreds, or even thousands, of people will die immediately from radiation exposure? Would the radiation spread all over the Japan, even, as another commenter asked, across the world? What about long-term effects - could hundreds of people develop cancer as the years go by?
Reply | Report Abuse | Link to thisI'm a veteran of the U.S. Navy Nuclear Power Program. I'm a qualified Reactor Operator and Reactor Technician and served 4 years in that capacity on the nuclear powered U.S.S Enterprise. I also worked at Lawrence Berkeley and Sandia National Laboratories. I have many friends and acquaintances still working in the nuclear power industry.
Reply | Report Abuse | Link to thisI read the article suggested by Mr. Adams as to the worst possible outcome from an accident of a light water nuclear reactor. The article was written by nuclear industry representatives. It is more like a best case scenario than a worst case scenario. Nuclear power plants can be operated safely, but the fact is they are risky. The backup and containment systems are hardly as robust and foolproof as the article makes them out to be.
The article cites the Three Mile Island accident as proof there is little chance of a Chernobyl-like disaster from a meltdown in a light water reactor. Rubbish! TMI is NOT a good analog for what is happening in Fukushima. TMI never suffered a loss of power, or a complete failure of all of their cooling systems. They never had an overpressure situation. They never lost the ability to maintain coolant flow to the core. They made a series of boneheaded operator errors that uncovered the core for a relatively short time resulting in partial melting of some of the fuel assemblies in the core.
We are talking orders of magnitude difference in severity of accident. For instance there was never a thought of injecting cooling pond water + boric acid into TMI. At Fukushima, they have already resorted to the absolute last ditch, desperation effort to prevent a total core meltdown and containment breach -- injection of seawater + boric acid. This is unprecedented and has never happened in any light water reactor, military or otherwise -- ever!(Exception: there was serious nuclear accident aboard a Russian nuclear sub, that resulted in the crew abandoning ship and the sub sinking.)
The Mark I containment at Fukushima is nowhere near as robust as the containment at TMI. In fact, basically it's just a thick steel tank. Most credible nuclear engineers believe it would almost certainly fail if subjected to a complete core meltdown. If it breaches then we are looking at something way more like Chernobyl than TMI.
Finally the article cited only "30 provable deaths" from radiation at Chernobyl. I wish it were so. Most credible estimates put the immediate death toll at around 1000 and the long term toll from cancers and other radiation induced illness at 100s of thousands!
"Interesting choice of experts - a computer modeler and a lawyer"
Reply | Report Abuse | Link to thisI can't speak about the lawyer, but as far as the computer modeling goes, it's pretty much the only option for studying serious nuclear accidents -- there is no safe experimental way to determine, for example, what will happen in a situation such as the one we're seeing now. Fundamental physics and small, safe experiments will only get you so far. On top of that, literally *millions* of experimental reactors would be needed to test every potential failure mode and combination of failure modes. That is a challenge even in simulation, especially when you consider that you might have hundreds of inputs for a single simulation, but the nuclear industry is responsible for the development of some pretty important methods for making such problems tractable.
In the end, my point is simply this: Considering how important simulation has been in studying reactor safety and improving the safety of plants and waste storage, you might want to think twice before dismissing it. Some of your own arguments might rely upon it more heavily than you realize.
Rod Adams comments reek of pro nuclear propaganda. I am not an expert by any means but you clearly have an agenda. Saying that there is no danger unless you are inside the fence is laughable. You dont know what is going to happen. That is the truth of the matter. The containment vessel for any meltdown may not even hold and in that case an untold amount of radiation could escape. And the effects would be devastating.
Reply | Report Abuse | Link to thisLook at the effects of Chernobyl and tell us that Nuclear power is only dangerous inside the fence of the plant. Absolute rubbish as not every accident can be planned for and there are thousands of things that can go wrong. You are making that age old scientific mistake of believing you are infallible.
Have a watch of this and remind yourself of the consequences when it does go wrong. Its not worth the risk.
http://www.mediastorm.com/publication/chernobyl-legacy
I'm sure you will write me off as a fear mongering imbecile anyway, but someone who wont accept that there is any risk with nuclear power worries me lot more than people who acknowledge it is dangerous but think it is worth the risk.
It is my opinion that the fears of radiation are misinformed and generally overblown. Even a total worst case full meltdown, with containment breach, would not cause radiation dispersal on par with Chernobyl. The Chernobyl design incorporated graphite cooling, vs. light water, and most of the radiation was dispersed when the graphite rods (which wouldn't fit back into their slots after the initial event) caught fire after meltdown.
Reply | Report Abuse | Link to thisIt is difficult for many people to understand that which is 'invisible' (radiation). In the case of the partial meltdown -currently occurring- at the Japanese reactors, authorities have evacuated citizens within 20km of the reactors; people on the west coast of the US have nothing to fear.
I stopped reading the article you referenced at this point: "Even in that situation, with no evacuation
Reply | Report Abuse | Link to thisfor several days, the United Nations’
carefully documented investigation UNSCEAR-
2000 (11) reported that there were
30 deaths to plant operators and firefighters,
but no significant increase in mortality or
cancer due to irradiation of the public have
been observed (12, 13). A possible link between
exposure and thyroid cancer is still
under study (14). The terrible and
widespread consequences of that accident—
increased suicide, alcoholism, depression,
and unemployment (15), plus 100,000 unnecessary
abortions (16)—were caused primarily
by fear of radiation and by poor planning
based on that fear."
Look at the videos, talk to people who work there, look at the bizarre deformations that you dont see anywhere else in the world except Belarus. Someone like you actually makes me sick. If you have seen or met anyone from Belarus that has suffered from Chernobyl you wouldnt be spreading the nonsense that you are.
Sorry for this rant to all the other readers but I cant hide my contempt for someone like that.
The nuclear safety authorities have been telling us since Tchernobyl that a serious incident would be impossible. Apparently they had overlooked the tsunami case. They now tell us that this can only happen where reactors are built at sea level.
Reply | Report Abuse | Link to thisBut ice storms have happened in France and Canada, bringing down all pylons, telephone cables and blocking transport through black ice. water supplies are then interrupted. So we are just as vulnerable anywhere that has cold winters. (An ice storm is when everything gets covered with several inches of ice).
Great article!
Reply | Report Abuse | Link to this@npaarmlee:
Reply | Report Abuse | Link to thisminor correction: You mention iodide treatment in the case of radiation exposure >25mRem. It is an important thing to note that iodide is useful only to protect against one radionuclide that might be released in an accident, I-131. This radionuclide will be concentrated by the thyroid. If absorbed in moderate doses only, it can be a carcinogen. In high doses, like I give daily (on the order of 10-150 mCi) it will fry the entire gland, and thus is not carcinogenic (estimated glandular doses on the order of 10's of thousands of rads). Further it does not appear to be carcinogenic in other parts of the body at these dose ranges.
They iodine essentially saturates the gland with cold iodine, and the trace amounts of radioiodine will essentially be diluted out.
It does not have any protective effect whatever from particles or gammas in the environment. Thus, it is not a panacea for radiation exposure.
A current report from a Japanese source which seems authoritative (http://english.kyodonews.jp/news/2011/03/77392.html ) notes that the highest dose rate adjacent to the reactor has been about 1.5 mRem/hour, which was quickly brought down to about 0.15mRem per hour, a dose that I would not be concerned with (except if I were constantly exposed to it).
Since there has been no report of actual release of any significant amount of radioactive isotopes, any precautionary steps you might take on the west coast of the US are entirely unnecessary. (They may actually be harmful in some way in that they promote a psychological sense of danger where none exists.) In the eventuality of a radiation leak, you would certainly have at least one day, possibly several, to take some precautions.
I found your paragraph explaining the supposed worst case scenario unclear. You write:
Reply | Report Abuse | Link to this"if a core melts, it will slump to the bottom of the reactor vessel, probably melt through the reactor vessel onto the containment floor. It's likely to spread as a molten pool—like lava—to the edge of the steel shell, and melt through. That would result in a containment failure in a matter of less than a day."
You appear to be describing fuel rods melting, flowing to the bottom of the STEEL reactor vessel, which your expert appears to be defining as "a containment" structure, and melting their way through. This leaves the melted material inside the very much thicker CONCRETE containment structure where the molten material will be contained and not bother anyone.
At Three Mile Island, the partially melted core flowed to the bottom of the concrete containment and penetrated it to a grand total depth of FIVE EIGHTHS OF AN INCH. How is a melted core supposed to breeze through the many feet of the Japanese concrete containment in "less than a day"?
For a diagram of the GE designed reactor in question see http://i1107.photobucket.com/albums/h384/reactor1/BoilingWaterReactorDesign_3.jpg
If you look at the bottom of the drawing you see many many feet of concrete.
Perhaps you will clarify the paragraph in your article that I am questioning. I would like to know where these experts you consulted got their information that a melted core from this reactor could go through that much concrete in a day. Did they perform an experiment or read in the literature of one? Or did they come up with this out of their own heads?
Google the term:
Reply | Report Abuse | Link to this"Fukushima Nuclear Accident – a simple and accurate explanation"
for an even better explanation from the Brave New Climate site. It isn't the disaster the lay press is claiming to get you to read their stories.
Then Google: "Reactor Design Edges Toward Approval"
I want to know this exact same thing. My husband and toddler, as well as his family w/ young kids and parents live in the East Bay (and LA). I spent almost all Saturday trying to research precautions, affects, etc...if nuclear particles came west only to find nothing. I find this questionable because there is much alarm in the news-—but no "what does this mean" in terms of the US. Not to mention for those of us that like to have backup plans—why won't someone give us bottom line in pedestrian terms what this means for Bay Area folks? Do we plan to leave (go east)? What about our gardens/farms (especially if organic)? What about pets? I have a zillion questions as you can imagine. So, if anyone-anyone can point me in the right direction I'd appreciate it.
Reply | Report Abuse | Link to thisAdditionally, I have a friend who landed in Tokyo 15 minutes before the quake, flew North (a day delay to original vacation plans) and is now seeing the sights with the friend they were visiting. What I find really odd is that their post via Facebook indicates a beautiful country and zero concern over a meltdown. So, what I don't know is (a) are we being informed accurately (b) why is the Northern area not getting what we are seeing/reading on the news regarding the nuclear reactors (c) in general—what is really going on?
I want to know this exact same thing. My husband and toddler, as well as his family w/ young kids and parents live in the East Bay (and LA). I spent almost all Saturday trying to research precautions, affects, etc...if nuclear particles came west only to find nothing. I find this questionable because there is much alarm in the news-—but no "what does this mean" in terms of the US. Not to mention for those of us that like to have backup plans—why won't someone give us bottom line in pedestrian terms what this means for Bay Area folks? Do we plan to leave (go east)? What about our gardens/farms (especially if organic)? What about pets? I have a zillion questions as you can imagine. So, if anyone-anyone can point me in the right direction I'd appreciate it.
Reply | Report Abuse | Link to thisAdditionally, I have a friend who landed in Tokyo 15 minutes before the quake, flew North (a day delay to original vacation plans) and is now seeing the sights with the friend they were visiting. What I find really odd is that their post via Facebook indicates a beautiful country and zero concern over a meltdown. So, what I don't know is (a) are we being informed accurately (b) why is the Northern area not getting what we are seeing/reading on the news regarding the nuclear reactors (c) in general—what is really going on?
This is a good discussion, and I'm glad it's hosted here.
Reply | Report Abuse | Link to this@pshaffer Thanks for the comments on iodide. I'm aware that it only provides protection against iodine. From my understanding, long term thyroid damage would be the main direct biological concern, given that iodine is quickly concentrated in the thyroid. Cs would be a longer term agricultural concern if it were deposited at high levels, which I would not necessarily expect to be the case at a distance. We should have data on that from Chernobyl fallout in Europe and cold war nuclear testing.
Short term exposure to iodine is worth considering on its own because it's physiologically concentrated in the thyroid, raising the effective exposure, because there's a way to prevent this, and because the iodine isotope has a short half life (8 days). That exposure is actionable.
I'm confining my discussions & questions to what can and can't be done, what's reasonable over the coming days, and what the rational risk assessment appears to be given many unknowns. The politics of nuclear energy can wait since I don't expect any new reactors to be built this week.
Several people (scientists in WA and CA) asked me about KI pills. I agree that mass distribution would have a psychological effect that may be unwarranted, since there are general misconceptions about radiation exposure. Risk assessment is a notoriously difficult concept to communicate. It's something I deal with in my work (genetics), so I'm interested in data and capable of digesting it.
My information on KI was from here:
http://www.hps.org/documents/kifactsheetdetail.pdf
I'm curious to know how a trained medical professional would decide for their own family, when to take it.
One note, from the Kyoto link, readings were given in microsieverts (1557/hour). NYT gave similar numbers, also in microsieverts (~1205/hour). These numbers are similar enough. From the conversions given here:
http://www.nrc.gov/reading-rm/basic-ref/teachers/05.pdf
1205 mSieverts~=1.2 Sieverts
1 Sievert=100 REM
So 1.2 Sieverts=120 REM (not mREM)
And from here:
http://www.nrc.gov/reading-rm/basic-ref/teachers/09.pdf
Vomiting is an effect at 100 REM, higher exposures are obviously worse. IMPORTANTLY remembering these are onsite exposures, not exposure to the general population and essentially irrelevant to populations at a distance where time & dispersal will have reduced those levels by many, many fold. Still those levels seem more consistent with onsite reports of radiation sickness in a small number of people with high exposure.
@sukibean My direct experience comes from handling radioisotopes in lab experiments and the certification training for that. It's a very different situation, but the principles of shielding and exposure hold.
Reply | Report Abuse | Link to thisThe risk appears to me very low, even if radiation did reach the west coast, and it's not clear to me whether it would at any appreciable levels. It would depend on how much was released, and how the winds carried it.
That said, best practices recommend reducing exposure to the minimum necessary. The levels I believe we would be concerned with would be low enough to be easily shielded. Erring on the side of (probably excessive) caution, I asked my family to plan indoor activities, not stand out in the rain, not dig in the garden this week. Choose a different day to have a picnic and lay on the grass.
I'm comfortable with this because these are small changes. I don't see a reason to stockpile duct tape or leave the area (or anything else drastic). Even this much is likely excessive, from what I can see, but again, there is zero cost to eating in the kitchen instead of on the porch. I'm not panicking.
"we're in a land where probability says we shouldn't be."
Reply | Report Abuse | Link to thisIf you don't have a backup to the backup of the backup that would, for every possible known contingency, prevent a meltdown, then you have cut corners. And in an area where massive earthquakes are well known to happen the loss of electrical power that is required to prevent such a disaster should have been known to be more than a possibility, and should have been moved into more than likely probability column to happen. Total failure by someone(s) who has expert credentials.
Dear Rod,
Reply | Report Abuse | Link to thisI find it sad that you must try and discredit us 'lowly' citizens who have great interest in nuclear matters, but who may not hold the all-important credentials you hold in such high regard. Please remember that it was credentialed men who designed these plants, and sited them on a coastal plain, on a Pacific island with a very long history of tsunami.
Despite not being a nuclear engineer, I do posess a brain and the ability to read and process information from many sources. I have been within one commercial reactor control room in my life(Humboldt Bay), and viewed the storage pool containing spent fuel, with a family member who was design engineer for Diablo Canyon.
You lose credibility when you talk-down to others.
Perhaps your retirement fund is in nuclear stocks, or you work in the fuel supply chain? Please disclose your nuclear interests.
Please note that I directed folks to the nirs.org site where they could find the GE Reactor family fact sheet.
They also list a Japanese site, in English, where citizens are reporting on local news from the Fukushima plant area, where they are sporadically in contact with an employee in one of the plants via mobile phone.
Warning; this is a Japanese anti-nuke site.
http://www.greenaction-japan.org/modules/wordpress1/index.php?p=2
May you and yours always be safe from unanticipated releases, and may this emergency resolve with no more deaths or exposures,
Cheers,
Anthony
"So we're in uncharted territory, we're in a land where probability says we shouldn't be..."
Reply | Report Abuse | Link to thisCome on guys, this is Japan, where the word TSUNAMI was invented precisely because they happen very frequently! It certainly was probable that a large quake/tsunami would take out at least one of their dozens of nuclear power plants. Nature Bats Last.
Hey RA. Thanks for your knowledgeable reply. It helped me more than the article. Interesting as the article was it still (unintentionally) beat around the bush as things relate to this meltdown issue. I am a retired journalist but still "dumd" when it comes to anything like "meltdown." However, I can now tell those (not you) who are in the same boat as me that, a meltdown occurs when the coolant water fails to reach the containment vessel - allowing the temperatures within the vessel to reach 5000 degrees. At this pressure, the unstable uranium inside is vulnerable to any disturbance. And, if it is disturbed in anyway it will explode damaging or destroying the containment vessel and releasing dangerous radioactive particles into the air (atmosphere.) Hence a meltdown. Is that correct Rod?
Reply | Report Abuse | Link to thisAnd, What I have for you Rod is, does this radioactive material stay in the air and drift around the world. Or, how far does it drift and how long does it stay in the air? I couldn't find these out.
@nparmalee:
Reply | Report Abuse | Link to thisThis is not a slam, just a clarification:
It looks like in your conversion from MICROSieverts to REM you instead used MILLISieverts to get a dose rate of 120 REM/hr at the plant fence. Since you left out a factor of 10^3, it should be 120 mREm/hr. This means it is VERY unlikely anyone not inside the plant, unless they are holding a vigil at the fence, would approach a dose of 100 REM.
My math:
1204 microSv/hr * 1REM/0.01Sv * 1Sv/1E6 microSv * 1000 mREM/REM = 120 mREM/hr.
If I remember correctly, the highest dose rate at the TMI fence was 10 mREM/hr, so this is already an order of magnitude greater.
Rechecking my own calculations. Last night I thought I had read milliSieverts (mSieverts), but what's being reported is microSieverts (uSieverts). Large error on my part. The reports of radiation sickness seem more consistent with milli being correct, but those could have been workers inside the plant exposed to much higher doses than that. Mea culpa.
Reply | Report Abuse | Link to this@nparmalee:
Reply | Report Abuse | Link to thisAs a trained medical radiation professional (nuc med physician) I will tell you that I would not take KI myself until there was a documented release of I-131 that was coming toward the US, and there has not been yet. On one hand, KI is harmless, on the other, why bother?. Incidentally, most over the counter multivitamins have enough iodine to protect you.
Even then the question arises: what is the risk. I haven't recently reviewed the data from chernobyl and Hiroshima, but suffice to say that the data in this area (radiation induced cancers) in general is very diffuse and ill defined. Little hard data, much estimation, usually skewed to the most conservative (meaning: highest potential risk) estimates.
Further: the risk is that of an induced thyroid cancer. These are not like breast, colon, renal, lung cancer. These are in general extremely indolent and easily treatable cancers. I regard them to be annoyances rather than life threatening situations. I treat up to 5-6 per week and rarely see someone who is in trouble. (yes - there are rare exceptions).
So, all in all, the degree of alarm is far out of proportion to the potential harm.
I'm most impressed with the civility and intelligence of this discussion. If I understand correctly, it sounds as though those of us living in the San Francisco Bay Area have little risk of nuclear contamination. That is certainly a relief. But what is the worst-case scenario for the people in Japan? Might hundreds or thousands of people die immediately from exposure to radiation? What about the long-term effects?
Reply | Report Abuse | Link to this@perry64 I was catching my own error just as you posted and hadn't yet refreshed to see your comment. Thank you, yes. I posted the links to the information I was using in hopes that if I was making an error, someone would catch it for me. You're the only one who called me on it, thanks for being sharp on this.
Reply | Report Abuse | Link to thisAfter reading many if not all the excellent replies on this site, can anyone comment on my reply/comment re: In reply to RodAdams -- "Hey RA." by Lenni. ???
Reply | Report Abuse | Link to this@pshaffer Thank you for sharing your expertise here. This kind of information is very helpful.
Reply | Report Abuse | Link to thisMy father had thyroid cancer last year and had a thyroidectomy. Another friend had the same many years ago. Both are fine. It was a hassle, of course, and getting the dosage right for thyroxin replacement was not fun, but also not devastating. As a worst case, it could be worse.
From my perspective, this was a matter of waking up to the news yesterday, and seeking information to assess an unknown, applying rational scientific principles to a question largely outside my field. I do hope that raising the questions in the first place hasn't sounded alarmist. It shouldn't be. I know of quite a few people, scientists and non-scientists alike, asking the same questions, and there are ways to work them through.
If anything, I think this thread has been an interesting exercise in how to rationally assess a potential threat, and determine whether a real threat even exists. What I've come up with is that no action seems necessary. But if I want to be hypervilgilent and possibly overreact, I could maybe take a multivitamin, maybe eat some kelp, and not play in the rain. For the sake of (most likely unnecessary) extra peace of mind. In my own judgement, any measures that involved a real departure from routine would need more evidence.
Thanks again for sharing your knowledge.
What are the odds of a melted core (corium) reaching criticality at some point either in the reactor vessel or on the containment floor once melted through? If the possibility doesn't exist why are they injecting boric acid with the seawater? Also, is the seawater being pumped into the reactor vessel or is it being used to flood the containment building in anticipation of the corium melting through the reactor vessel?
Reply | Report Abuse | Link to this@David Lewis:
Reply | Report Abuse | Link to thisMinor correction:
You wrote:
"At Three Mile Island, the partially melted core flowed to the bottom of the concrete containment and penetrated it to a grand total depth of FIVE EIGHTHS OF AN INCH."
Actually the partially melted core flowed to the bottom of the steel pressure vessel and penetrated it a grand total depth of five eights of an inch.
Before it could contact the concrete, it would have had to work its way through about 6 inches of steel and then some foundations.
Rod Adams
Publisher, Atomic Insights
Reply | Report Abuse | Link to this(Nice to see you here, Mr. Adams!)
http://atomicinsights.blogspot.com/2008/03/nuclear-war-of-words-in-california.html
You wrote
Reply | Report Abuse | Link to this"One note, from the Kyoto link, readings were given in microsieverts (1557/hour). NYT gave similar numbers, also in microsieverts (~1205/hour). These numbers are similar enough. From the conversions given here:
http://www.nrc.gov/reading-rm/basic-ref/teachers/05.pdf
1205 mSieverts~=1.2 Sieverts"
In the document that you have linked to, the m stands for milli (1 x 10^-3) not micro (1 x 10^-6)
1205 microSieverts = 1.2 milliSieverts = 120 milliRem.
"Interesting as the article was it still (unintentionally) beat around the bush as things relate to this meltdown issue. I am a retired journalist but still "dumd" when it comes to anything like "meltdown." However, I can now tell those (not you) who are in the same boat as me that, a meltdown occurs when the coolant water fails to reach the containment vessel - allowing the temperatures within the vessel to reach 5000 degrees."
Reply | Report Abuse | Link to thisThe term 'melt' means the same in a nuclear reactor core as it does for any other solid material. It means that the material undergoes a phase change from solid to liquid. The transition requires the input of a very large additional amount of heat energy called "the latent heat of fusion." Think about it this way - how much energy - from the sun or some other source of heat - do you have to add to make a large volume of ice melt, even if the surrounding air temperature is above 32 F (0 C)?
The core of a nuclear reactor is not all the same material and some will start melting at a lower temperature than other materials. The corrosion resistant cladding will melt long before the uranium dioxide ceramic pellets. Some of the fission products are gases at the temperatures in a reactor core and will leak out as soon as the cladding is damaged. Among others, those volatile fission products include Xenon, Krypton, Cesium (boiling point of 641 °C) and Iodine.
"At this pressure, the unstable uranium inside is vulnerable to any disturbance."
No. You have confused temperature and pressure.
"And, if it is disturbed in anyway it will explode damaging or destroying the containment vessel and releasing dangerous radioactive particles into the air (atmosphere.) Hence a meltdown. Is that correct Rod?"
No. If the material in the core is generating enough heat energy to melt, it will slump down like melting butter. When it contacts the thick steel pressure vessel, it will need even more heat to bring that barrier up to a melting temperature and then to overcome the latent heat of fusion for a large mass of metal.
At TMI, the melting core material only had enough heat being generated to melt the first 5/8ths of an inch of the pressure vessel before the whole mass froze up again. The longer the operators provide cooling, the less heat production will be available.
"And, What I have for you Rod is, does this radioactive material stay in the air and drift around the world. Or, how far does it drift and how long does it stay in the air? I couldn't find these out."
Almost none will leave the containment barriers.
Hi Janis. Thank you for remembering and providing the link. Good thing we have computers and Google; my memory just is not what it used to be.
Reply | Report Abuse | Link to thisGood to see you here.
Anthony - I am pretty certain that I did not talk down to anyone, though I did try to discredit your organization. I have no respect for people who work so hard to destroy and discredit some of the most valuable science and engineering accomplishments of the entire 20th century.
Reply | Report Abuse | Link to thisIn a world where people need reliable, controllable power to accomplish tasks and to live comfortable lives, there are essentially two choices - burn chemical fuels or fission nuclear materials. All other proposed choices are more a matter of gathering weather dependent and diffuse sources.
The world's dependence on fossil fuels is legendary. It has enabled the development of modern society, but it is becoming clear that the limits are near.
Fortunately, we now understand how to release and control the far more concentrated energy that is inside certain atomic nuclei. A pound of uranium contains more than 2 million times as much energy as a pound of crude oil. Releasing that energy produces slightly less than a pound of waste material that can be fully contained and isolated from the environment for as long as necessary.
I spend a great deal of time trying to share what I know. I grew up in a family full of teachers. In that world, the highest respect you could pay to someone was to share knowledge in the expectation that they would learn something.
Because I feel a debt to American taxpayers for having paid for my education, I rarely charge anything to share what I know. I do not think of that attitude as "talking down" to anyone.
Rod Adams
Publisher, Atomic Insights
@RodAdams Yes, thank you. I did eventually catch that. Inexcusable, really, because I convert micro and milli all the time. In this case, the units are unfamiliar to me, so part of my effort has been to try to establish a scale of reference for myself.
Reply | Report Abuse | Link to thisI had a chemistry teacher once who made us memorize the distance to the moon, and the radius of the sun, and put it on the exam. His point was that one should always check results against some scale of reference and ask whether they make sense. It is helpful in assessing risk from radiation, in general, to have some sense of scale, for instance, this site (http://www.radiation-scott.org/radsource/2-0.htm) gives the exposure for a 12 hour round trip flight from San Francisco to Washington DC as 6 mrems (millirems).
That said, my sense of scale is completely blown when I watch video of the force of water engulfing entire towns. Putting things in perspective is a significant challenge here, on many levels.
LikeMinds wrote:
Reply | Report Abuse | Link to this"I'm a veteran of the U.S. Navy Nuclear Power Program. I'm a qualified Reactor Operator and Reactor Technician and served 4 years in that capacity on the nuclear powered U.S.S Enterprise. I also worked at Lawrence Berkeley and Sandia National Laboratories. I have many friends and acquaintances still working in the nuclear power industry."
I am also a Navy nuke. On my last ship, I was the Engineer Officer. For those who do not know much about the Navy's system, I was one of the final signatures on the qualification cards for junior reactor operators and reactor technicians. I was also responsible for training and qualifying the Engineering Watch Supervisors and the Engineering Officers of the Watch who supervised the actions of the Reactor Operators. My bet is that LikeMinds never spent much time "in the chair" if he was only in the nuclear Navy for 4 years.
I was the guy who designed the training program and ran the small group seminars that were aimed at brainstorming how we would respond to all kinds of unforeseen circumstances.
I served on two different submarines and qualified for Command of a Nuclear Submarine, though I never got around to serving in that capacity due to some career choices.
The last time I checked, neither Lawrence Berkeley nor Sandia have any power reactors in operation.
Please take his comments with a pinch of salt.
By the way, the United States once had a President who claimed to be a Navy nuke. The only problem was that history shows that he resigned his commission in October 1953 and went home to farm peanuts. The USS Nautilus, the very first nuclear submarine in the world, did not report "underway on nuclear power" until January 17, 1955. The very first nuclear plant that the Navy built and operated reached its initial criticality in Idaho in the summer of 1953, while that president was still in nuclear power school. He had only started class in March 1953.
Interesting, don't you think?
Here is an excellent article that explains in great depth the nuclear engineering:
Reply | Report Abuse | Link to thishttp://bravenewclimate.com/2011/03/13/fukushima-simple-explanation/
An aside - there is NO chance of a nuclear explosion as asked above. Question re boron: it absorbs neutrons avidly and thus helps cool the reactor.
I also experienced Chernobyl from Germany. The worst exposure came from respiration of contaminated air during the first few days. Food was a secondary concern. I joined a parent´s group which gave us access to measurements of radionuclides in our food, which I monitored for 2 years. We probably did not suffer signifcant health effects at over 1000 kilometers away from the meltdown, although two family members have developed thyroid conditions and two died prematurely of cancer. The problem is that in a globalized world, the contamination can also spread via food. Certain European fish, meat and plants are still contaminated today, and contaminated milk powder from Europe was later sold all over the world and thus entered unadulterated food chains because no producer was willing to absorb the cost of loss of the milk powder. This is typical zero-sum behavior and to be expected, though I was shocked at such a lack of ethics at the time. That is why it is irrelevant if our family in particular were harmed or not--the industry has simply lost its credibility in our circle (as have others, such as the amazingly large and lucrative illness industry). We routinely vote against nuclear proliferation, since producers are obviously not able to offer adequate safety, proven once again in the latest disaster. This sort of rejection is a logical consequence of irresponsible behavior, and it is naive to assume consumers are asleep. On the contrary, we have a long memory and our opinions also affect the next generation or two.
Reply | Report Abuse | Link to thisthis version seems much more reassuring
Reply | Report Abuse | Link to thisbut only because i can understand the logic
http://bravenewclimate.com/2011/03/13/fukushima-simple-explanation/
Thanks RodAdams for actually adding some information here. It has been extremely frustrating to watch the stream of yahoos who have been trotted out in media such as FOX News and CNN as "nuclear experts" who obviously know little to nothing about the reactors in question. Furthermore, it is pretty clear that reporters simply haven't a clue about anything to do with nuclear technology. There is, for example, no recognition by any of them of that fact that natural background provides a reasonable scale of radiation exposure to the public and furthermore that releases to date from the Fukushima plant are apparently within or only slightly above legal release limits this far (or am I wrong about this - it is really hard to extract ANY meaningful information from what our media report). I accept the assertion that there is a very low probability of a major containment breach and release of significant quantities of radioactive material. I guess my one bit of surprize in the whole affair is that in this reactor design the decay heat alone is enough to melt the core when active cooling is not maintained (or at least that is my inference from what I am hearing). Is this generally true of pressurized water reactors? Is there any difference between light and heavy water (or other types) in this regard?
Reply | Report Abuse | Link to thisBy reaching criticality I did not mean an explosion. I meant that the core would start and sustain a nuclear chain reaction. I thought that all reactors reach criticality when they produce power.If I am using the wrong term (criticality) I apologize. I realize there is no chance of a nuclear fission explosion. But if a chain reaction were to commence then the heat levels would presumably skyrocket and we would be in uncharted territory and therefore the past experience with 3MI would not provide so much comfort. So, the reactor was scrammed immediately when external electric power was lost. If they are not concerned about the molten pile chain reacting again then why the insertion of boron to absorb neutrons? This would not have any effect on the heat produced by decay. So what are the odds of the molten core starting and sustaining a fission chain reaction?
Reply | Report Abuse | Link to thisIs there a nuclear engineer or physicist out there who is not connected to the nuclear power industry who can weigh in here? Someone whose fortunes are not tied to the outcomes?
Reply | Report Abuse | Link to thisThis is a good and enlightening article. I was interested to find out the number of nuclear weapons detonated since my birthday with AtomicAge:
Reply | Report Abuse | Link to thishttp://apps.facebook.com/atomicage/
There have been 516! You should be aware of the dangers of nuclear technology.
@tomkovic:
Reply | Report Abuse | Link to thisI am not a nuclear engineer by academic degree, but I was trained, formally qualified and assigned to that position through the Navy nuclear power training program.
I currently work for B&W on the mPower reactor team, but I only started that job in September 2010. Until that time, I was a professional officer in the US Navy who had received nuclear power training and served as an engineer on nuclear powered ships, but none of my income was due to a connection with any industry. I had a job to do in service to my country and was not asked to sell anything.
As a result of 33 years in uniform, I have the rather rare circumstance of a defined benefit pension and medical coverage that will last me through the rest of my life. I also have a BS with distinction from the US Naval Academy and an MS with distinction from the US Naval Postgraduate School. I spent 9 years on Washington DC headquarters staffs in a financial analysis and resource requirements role. My children are both adults, both married and both fully educated with all of those expenses paid for.
I am not trying to brag, but trying to tell you that I have many options and no real need to work.
I have chosen to become a nuclear energy professional because I see it as an opportunity to continue to serve and to help make a better world to turn over to my children and grandchildren.
Many of my friends in the nuclear industry are similarly motivated and similarly independent of the kinds of financial pressures that you imply are the reason for our support of the technology.
@tomkovic who wrote:
Reply | Report Abuse | Link to this"By reaching criticality I did not mean an explosion. I meant that the core would start and sustain a nuclear chain reaction. I thought that all reactors reach criticality when they produce power.If I am using the wrong term (criticality) I apologize. I realize there is no chance of a nuclear fission explosion. But if a chain reaction were to commence then the heat levels would presumably skyrocket and we would be in uncharted territory and therefore the past experience with 3MI would not provide so much comfort."
There are many orders of magnitude between criticality and what we call "self sustaining" power that is actually generating heat. Accidental criticality in unshielded containers is something to be assiduously avoided, but inside a vessel designed for safe operations at fission power levels in the neighborhood of a couple of thousand megawatts of thermal energy, it is not a big deal.
With regard to the possibility of a melted core attaining a critical condition somehow, I find that possibility to be close enough to zero to call it that.
The cores of power plants designed to produce economical power are arranged in their most reactive configuration with the optimal quantity of moderator between carefully spaced fuel pins. We do that to achieve the maximum possible fuel utilization in order to save money.
If the core melts, it will change shape and turn into something less reactive. If the material is melted, there is no room for the moderator - water - to do its job and our reactors are not designed to be able to achieve criticality without proper neutron moderation. That is especially true if the core was shutdown before any melting occurs because that means that the neutron absorbing control rod material is inserted into the core and will be part of any melted mass. Even when melted, materials like boron still absorb neutrons and prevent criticality.
Comment: it is a rare pleasure to have an intelligent online conversation with people interested in getting real information. (As opposed to say, turning every comment into a political jab at someone, which seems to be the standard for online communication now.) Thank you all.
Reply | Report Abuse | Link to thisIt would seem that the other four operating generators at the plant could provide enough electricity for the downed unit. Rerouting the connections would be the problem. There ought to be huge trailer mounted generators and or pumps mounted on rocket launcher sized trucks available. Since nuclear plants are near oceans, special ships should be similarly equipped. Why not???
Reply | Report Abuse | Link to thisFine, there is a real problem...power to the power station- Find 2 large barges-put 5 or 6 200kw+ generators on them- fill them with diesel and barge them into the cooling canals-rig some cabling-get the cooling pumps running. I understand the areas are in shambles, but instead of flying around in a helicopter waiting for a disaster why not HELP?
Reply | Report Abuse | Link to thisActually it would take much less than 50K nuke to supply the current world population with the same energy consumption as the US today - Much less with a conversion to nuclear and electric transportation fuels, and effective mass transit. Annual annual energy use much less than US average in warm states like CA. Most of the world population is in warm places.
Reply | Report Abuse | Link to thisWorld population projections are hard to make as birth rate drops quickly to less than replacement levels when women achieve education and job access.
In 1943 with 1% of today GDP Americans production of liberty ships was the equivalent of a nuke a day. The world could easily mass produce 10 times that today - so 10 years job done.
Core melt rates on old nukes are not relevant to new ones which are thousands of times less likely. In any case it appears the reactor just doesn't get anywhere hot enough to melt steel much less 6 inches of it once the fuel rods melt even without coolant. TMI proved that.
In this case we do not need to 'believe' either Rod or Vendicar. We are presented with a natural experiment involving the catastrophic malfunction of three operating nuclear power reactors built in the west. The fission product inventory was as high as it would normally be at the time of the earth quake (worst case). We know that the reactor design was not built to the current standards(again worst case for western designs). It appears that the emergency generators providing power to the coolant circulation pumps were all off line very quickly (worst case). We have reason to believe that there has been at least a partial melt down of the fuel. It is hard to conceive of a more challenging or more rapid system failure at a nuclear plant. This experiment then places an upper bound on the potential human exposure in a worst case western nuclear power plant accident. If a lot of people are killed by exposure to ionizing radiation (over 4 grays whole body dose/person)I would say that the antinuclear crowd is right. Heck, if the dose to members of the public exceeds 0.25 sieverts, I would say that Vendicar is right (this is the acute dose at which stochastic long term events such as cancer could be reasonably anticipated). If the exposure is so low that to predict human health effects we have to start discussing whether the linear no threshold dose response curve has a threshold or is linear below the known data then Rod is clearly correct. (Note, I use the gray for acute effects and sievert for chronic effects.)
Reply | Report Abuse | Link to thisIn either case we should know within a week.
Why couldn't they draw power from one of the ships in the area to power the cooling pumps...or at least provide enough power to keep the valves operational?
Reply | Report Abuse | Link to thisRod, you are helpfully providing some useful responses to this focused discussion.
Reply | Report Abuse | Link to thisThen, in a classic display of character deficit, you attempt to get in a dig at President Jimmy Carter (a man who hasn't done anything to you, either in this thread, or in your life).
It is irritating and childish behavior like this that lets people know to treat your proclamations with more than a little caution.
James - I have been personally harmed - career wise - by the decisions during the Carter Administration to favor increased coal fired power plant development while making it illegal to recycle used nuclear fuel, making it almost impossible to obtain a new nuclear plant operating license, and virtually shutting down the breeder reactor program.
Reply | Report Abuse | Link to thisOther than that, I guess I should give the guy a pass for lying about his Navy nuclear power training on his pre-campaign resume. Since he had become a politician, I suppose that meant that he no longer abided by the Honor Code of our mutual alma mater. (Midshipmen do not lie, cheat or steal.) I always admired the West Point version (Cadets do not lie, cheat or steal or tolerate those who do.)
The pumping of seawater into the boiling-water reactor design will cause more problems even if the cool down is successful. The shell, core, rods and mechanical equipment(turbines,pumps, etc.) materials are not designed for sea water. The easiest example would be what would happen to your automobile after it became submerged in sea water. You certainly cannot dry it out and put it back into service. Sea water is very corrosive and costruction materials must be designed properly to prevent damage and faiure. The same applies for a nuclear power plant. Of course the present issue of a pending melt down has highest priority and must be addressed. If your car was burning and you drove it in to the ocean you certainly would put out the fire. You can always buy another car or design a future nuclear power plant near an ocean to handle sea water in times of an extreme emergency.
Reply | Report Abuse | Link to thisOne thing I'm just amazed by is the bravery of the workers at the plant. They are risking their lives to try to save their countrymen and women from dying of radiation poisoning.
Reply | Report Abuse | Link to thisJapan's nuclear safety agency says it suspects a reactor's container has been damaged, and the agency fears a radiation leak. If the container gives way, isn't this the worst-case scenario - a release of radiation that will kill hundreds, maybe thousands of people and contaminate a wide area for hundreds of years?
With a third explosion taking place, damage to the container and a radiation leak, aren't we getting into worst-case scenario land?
Maybe that accident gives people and countries now the time to look at an alternate power source.
Reply | Report Abuse | Link to thisI discovered the technology of the Flying Saucer and patented it. Nasa was not interested, it would make the Rocket Industry obsolete.
So now I can offer it to the world to generate electric power, the most economical and safest way. No pollution or noise.
A one thousand ton weight can be lifted 1000 feet, with only a few hundred watts, using ther technology.
When it comes down, it can generate thousands of Kilowatts.
The structures are silos, with the weights sliding up and down alternately.
The Gravity Control Units are installed and LEASED only to give the investors and Taxman their due.
It is more economical than wind, water, solar, or nuclear systems and it is completely safe.
Read up on it at >One Terminal Capacitor Joseph Hiddink<
and see the Patent at > www.rexresearch.com/hiddink/hiddink.htm <
The Washington Post in an article by Eric Talmudge "Residents warned to stay indoors near Japan nuke plant after new, catastrophic radiation leak" just stated that the radiation exposure levels at the stricken plant are now 400,000 microsieverts per hour. I wonder if this can be correct as it seems to me that this rate would fatal in just a few hours. They report that of the 1,400 workers, all but about 50 are now evacuating; volunteers will stay to work on the cooling effort.
Reply | Report Abuse | Link to thisI think you're spruking for the industry there Rob. Fukushima is currently releasing enough radioactive material that an hour of exposure will drastically reduce white blood cell counts. Gee, what would happen if you got two? J-Government is advising everyone within 30 km to stay indoors. 30 km means 30 km from that fence you mentioned. Why don't you go check it out for yourself, Rob? Spend a couple of hours there and let us know how safe it is.
Reply | Report Abuse | Link to thisI think you're spruking for the industry there Rod. Fukushima is currently releasing enough radioactive material that an hour of exposure will drastically reduce white blood cell counts. Gee, what would happen if you got two? J-Government is advising everyone within 30 km to stay indoors. 30 km means 30 km from that fence you mentioned. Why don't you go check it out for yourself, Rod? Spend a couple of hours there and let us know how safe it is.
Reply | Report Abuse | Link to thisRod, you also forgot to mention that the J-Gov aren't allowing journalist within 60 km of the plants - it's getting harder to get near that fence, isn't it? Anything to say on the fact that No. 2 uses MOX fuel and that is it contains more plutonium and thus will kill more in the interim and more in the long term than uranium fueled reactors disasters.
Reply | Report Abuse | Link to thisYou are just making up numbers. The number is 50000K nukes to supply the world's population at US standards as I explained to you.
Reply | Report Abuse | Link to thisShow us a link or your calculation. I will then proceed to demolish it.
Suppose we pour in liquid Nitrogen or liquid helium through some vent. Will it not cool the contents immediately and give us some more breathing time for the workers.
Reply | Report Abuse | Link to thisRod Adams
Reply | Report Abuse | Link to thisI am grateful for your authoritative voice on this thread. The misinformation and the dearth of technical details from both US and Japanese media outlets has been very frustrating.
After the earthquake hit, all four Dai-ichi reactors automatically went off line as designed and (presumably) backup power went online to control them. After the tsunami hit, the backup power for reactor 1 reportedly failed. The implication is that backup power for the other three reactors remained operational. Why did backup power systems for the three reactors not support the load of a reactor 1?
Why, days after the explosion in the reactor 1 building, did the backup power for reactors 3, 2, and finally 4 fail? The only reason I can think of is they ran out of fuel. Days seems to be sufficient time to ensure continued operation of the backup systems. Even with the aftermath of the tsunami on the local population to contend with, the urgency of the Dai-ichi situation should have had the highest priority.
After hydrogen explosions occurred in reactors 1 and 3, why would the buildings housing reactors 2 and 4 not be opened to allow the hydrogen to disperse into the atmosphere rather than to accumulate in a confined space? It just makes no sense that explosive dispersal of contaminated material (and destruction of critical sensors and control components) rather than dispersal of a lesser quantity of contaminated material by venting would be a preferred plant design decision.
Is all the seawater being pumped into the reactors being boiled off as steam or are there streams of contaminated water returning to the sea?
Some of these questions have already been raised in this thread but I have not seen them answered.
Richard Aldridge
Retired EE
"The probability of this occurring is hard to calculate, primarily because of the possibility of what are called common-cause accidents, where the loss of off-site power and of on-site power are caused by the same thing. In this case it was the earthquake and tsunami. So we're in uncharted territory, we're in a land where probability says we shouldn't be."
Reply | Report Abuse | Link to thisThere are currently about 500 Nuke plants world wide operating or under construction.
"The cumulative operating experience amounted to 14,174 years by September 2010."
( http://www.euronuclear.org/info/encyclopedia/n/nuclear-power-plant-world-wide.htm )
The thing with probability is this, as you multiply the number of lottery ticket you buy, you multiply the number of chances that a non-probable event will occur. It seems that in 14,000 operation-years, at least three extremely serious non-probale events will occur. This is because humans are greedy and do all they can to subvert costly regulations, and even without that, we are fallible.
If we are to build hundreds more plants, then accidents such as Chernobyl, TMI and Fuk-Dai are inevitable. Do you think 10 days ago the operators of that Japanese plant were any less sure that it could never fail then are the operators here?
The next question is this: Who will pay for the failure of the plant? Many will pay. The people who are injured, the people who may lose their homes due to radiation contamination, the consumers of the electricity, the Japanese nation as a whole, the rest of the world in as much as we participate in an economy that is seriously injured by this event. That is to say - We are all paying a price for it! Yet this is a cost that is not factored into the cost of building a plant.
Let's require that every Nuke plant in the world must purchase a $2 Trillion insurance policy before they can start building.
See: http://www.gregpalast.com/no-bs-info-on-japan-nuclearobama-invites-tokyo-electric-to-build-us-nukes-with-taxpayer-funds/
And there is the question,
@ RodAdams
Reply | Report Abuse | Link to this"While a commissioner, he was part of the team that spread a great deal of confusion in the aftermath of Three Mile Island because he did not really understand the technology, the chemistry or the physics of what was unfolding."
Are you suggesting that one needs an advanced degree in chemistry or physics in order to say anything reliable about nuclear power?
Yesterday this blog was informative & civilized...it is unfortunate that the crazies have found it & now waste my time with incessant poking at each other. Really, what is your point of dissecting each other's credentials & focusing on the minute details of people's remarks looking for vulnerabilities? If you are so interested in picking scabs then pick your own. Some people came her for information, not sport. It's just tiring to those of us who are looking for understanding of the events unfolding in Japan. Please stick to the issue at hand.
Reply | Report Abuse | Link to thisVendicar doesn't seem to have even a grade school grasp of elementary arithmetic or science.
Reply | Report Abuse | Link to thisIts obvious he simply makes up his numbers out of the air.
I ask for links or calculations Vendcicar gives more bullshit.
The 50000 reactors stands.
Modern reactors are thousands of times less likely to have core accidents and if they do there are of little consequence. So no accidents at all of any significance.
Learn something Vendicar before you spew more nonsense.
Anti - nuclear zeolots generally shill for Big Oil. Vendicar here is one of the worst examples of Denier, spewing junk science and obviously not believing in the science that says we have less than ten years to solve the GHG problem.
Nuclear deniers don't give a rat's ass about the 3 million people worldwide killed annually by coal pollution having no timely solution to its elimination. They oppose the nuclear solution without cogent argument knowing full well every year you can delay kills three million more.
Since the nuke accident itself has killed nobody so far other than a crane guy and there is no evidence of anything other than low level radiation release the insurance should be very small compared the insurance warranted by the thousands killed in gas and oil plant explosions and dam bursts. The large areas made toxic forever by the refinery destruction should make insurance for these industries many thousands of times as high as nukes.
Reply | Report Abuse | Link to thisSince the modern nuke is thousands of times less likely to have the kind of accident this ancient reactor suffered, insurance rates should be almost nil. Perhaps they should apply for a reduction?
"Other than that, I guess I should give [Jimmy Carter] a pass for lying about his Navy nuclear power training on his pre-campaign resume."
Reply | Report Abuse | Link to thisI don't think Carter ever claimed to have served on a nuclear sub. What he DID claim is that he worked on the design of the propulsion system for the Seawolf (true) and that he was deployed to Canada to assist in the shutdown of the Chalk River reactor when it melted down (also true). Maybe I'm stupid, but I presume the Navy would not use untrained personnel in either of those situations (and if you say they would, what are we to make of your own experience?). Regardless, it is Carter's experience at Chalk River that is said to have colored his perceptions of nuclear power, so maybe you should blame the folks in Canada who melted their core instead.
You make my point but are to dumb to see it.
Reply | Report Abuse | Link to thisSpace shuttle and Apollo are both ancient technology.
Certainly their miles per accident are far less than a modern aircraft.
Sunlight and lightning are more deadly than nuclear power plant disaster. Chernobyl, the worst nuclear plant disaster in history, killed 250 people within 10 yrs. Skin cancer due to exposure to the sun's ultraviolet radiation kills 8,000 Americans every yr. While 400 to 500 Americans get struck by lightning and die every 10 yrs.
Reply | Report Abuse | Link to thisOf the 100,000 survivors of the Hiroshima and Nagasaki bombings exposed to intense radiation, 500 died of radiation sickness or 0.5% casualty rate. I hope there will be no casualty in the 50 Fukushima plant workers.
"I guess that means that mass murderers aren't dangerous because they kill fewer people than lightning."
Reply | Report Abuse | Link to thisWrong. Mass murderers are dangerous and kill more than lighning at a given time. Murder is intentional. Are accidents intentional?
Maybe those claiming and wanting higher casualties are the liars. What's your basis? Mine is Wikipedia. So Wiki is a nuclear zealot?
Don't predict and fabricate casualties. Use historical data. There was not a single death in the U.S. due to nuclear accident in the last 50 yrs. The 2 missing and 1 injured in Fukushima plant I suppose were not due to radiation.
I am scared because I just read a news story that quotes the chief of the U.S. Nuclear Regulatory Commission saying all the water is gone from the spent fuel pools at the most endangered plant and this means there is nothing to stop a meltdown. So now it seems that there will be hundreds of fatalities from radiation poisoning and the land around the plant will have to be abandoned for hundreds of years, is that right? Because there is no water left and apparently no way to immediately get water in there?
Reply | Report Abuse | Link to thisHere's the story:
http://www.contracostatimes.com/california-earthquakes/ci_17625323
I can't understand why they don't use portable generators to drive the pumps - wrong voltage maybe, but surely this is not beyond Japan's capabilities.Or why they could not have run fire hoses to keep the spent fuel rods cool.
Reply | Report Abuse | Link to thisThe Fukushima radiation fear may be exaggerated. The reported radiation level was 40 rem/hr. There is no known health hazard effect below 100 rem radiation dosage. If you're crazy enough to stand on the blown nuclear reactor unprotected by radiation suit for one hour, you'll get 40 rem. That's less than half the hazardous level. Sunbathing can give you over 100 rem and a sunburn.
Reply | Report Abuse | Link to this"It should be mentioned at this point that to provide a population of 15 billion people with energy, (exclusively derived from nuclear), at U.S. levels of consumption, would require the construction of 200,000" -Vendicar
Reply | Report Abuse | Link to thisVendicar, you've misplaced a decimal point or something in your calculations. The figure you quoted was too high.
Give every person a 2KW budget of electricity. 2,000 watts * 15 billion people = 3*10^13 watts. Assume a typical modern nuclear reactor provides 10^9 watts. (3*10^13)/10^9 is 30,000 reactors. 30,000 reactors would allow everyone to run his own air conditioner continuously always while still using the usual electronic equipment.
Perhaps you meant all energy, not just electricity. Then you're still way off; 50,000 reactors would be sufficient.
Thanks, Dr. Strangelove. That's reassuring. I guess a sunburn is actually mild radiation poisoning, yes?
Reply | Report Abuse | Link to thisYes, sunburn is actually damaged skin cells due to ultraviolet radiation. Overexposure to the sun can also cause skin cancer.
Reply | Report Abuse | Link to thisBtw, the Three-Mile Island nuclear disaster was the worst in the U.S. history. There was no casualty. The highest radiation dosage by the plant workers was 4 rem. You can get as much as 30 to 70 rem every year from cosmic rays, radon gas from the ground and other natural radiation.
When melting starts, control rods are any more effective? If not the effect of water, if still present inside the wessel, would be to restart nuclear reactions as a result of its moderating action. Woudn't be better to keep the core dry and let the melt down take place? No explosions and the fuel at the end should solidify somewhere, in the containement or underground, after a certain amounr of time when the temperature would decrease naturally.
Reply | Report Abuse | Link to thisWould it be possible to quickly come up with a very long bucket or attach a wide hose to the existing bucket that the Japanese are using to deliver water to the Fukushimo Nuclear Reactor?
Reply | Report Abuse | Link to thisI think that they did not do an adequate risk analysis for these plants. Certainly the risk of earthquake and tsunami is high in this area of the world and the potential to disable the AC and backup power during an event was unacceptably high. Why would you put backup power in an area which could be effected by an earthquake or tsunami? I wonder whether they were complacent or acting on economic considerations.
Reply | Report Abuse | Link to thisRod Adams writes:
Reply | Report Abuse | Link to this"In a world where people need reliable, controllable power to accomplish tasks and to live comfortable lives, there are essentially two choices - burn chemical fuels or fission nuclear materials. All other proposed choices are more a matter of gathering weather dependent and diffuse sources."
Adams claims expertise on nuclear power, not alternative energy sources. He should add qualifiers when he steps outside his field. He asserts without much evidence that alternative energy is infeasible.
My informed but layperson's understanding is that weather-dependent and diffuse energy sources do have the capability of providing all our energy needs using existing technology, albeit at a significantly higher cost than conventional sources. Intermittency and distributed sources can be handled with energy storage systems and power grids. We already know we need to make huge investments in new power grids. Energy can be stored e.g. by pumping water uphill to a hydroelectric pond, batteries, or by compresing fluids. Intermittency other than the diurnal cycle is mostly local; a grid system smooths out local fluctuations. The diurnal cycle can partly handled by charging up electric vehicles at night.
The true test of cost is competition in free markets, while using taxes and subsidies as minimally needed to compensate for possible externalities such as meltdown and global warming. Nuclear energy has a positive externality with respect to non-production of CO2, and a negative externality with respect to possible catastrophic risk.
Presently the nuclear industry receives a huge subsidy in the form of the Price-Anderson exemption, which means that catastrophic costs beyond a relatively nominal amount caused by a meltdown are shifted to citizens and taxpayers. In a fair market setup, Price-Anderson would be repealed and the the nuclear industry would be required to purchase bonded insurance to cover the full costs of catastrophic risk.
I have never heard a single nuclear industry spokesperson claim that nuclear power could survive in the market place on a truly level playing field, i.e. sans Price-Anderson.
Hence nuclear power is very likely to fail any reasonable benefit-cost test.
The preceding argument does not depend on technical progress. It is very likely that future technical progress will drive costs down much faster for new alternative energy technologies than it will for mature nuclear power technology.
David Burress
President, Ad Astra Institute of Kansas
www.adastrainstitute.org
Get 20 helicopter tankers, there are used to put out forest fires. Each can dump 3,000 gal. of seawater to cool the nuclear reactors. The sea is nearby. Cycle time may be less than 30 mins. Do this non-stop 24 hrs/day for 7 days or until the threat is gone. That should solve the cooling problem. Yes a very expensive solution.
Reply | Report Abuse | Link to thisMeltdown can be prevented by changing the containment material of the reactor. Currently, concrete and steel are used for containment. These materials will melt at 1500 C. When cooling system malfunction, core temp. can reach 2500 C or more.
Reply | Report Abuse | Link to thisUse 3 meter thick graphite in addition to concrete and steel as containment materials. The melting point of graphite is 3600 C. It will absorb much of the heat leaving the concrete and steel intact.
The US nuke industry has a $15B insurance fund far greater than the $150 million of deadly atomic bomb sized installations like LNG and chlorine storage carry - Far greater than deadly chemical plants and the cubic miles of deadly toxic forever mine tailing dumps and solar power cell reject piles all over the US.
Reply | Report Abuse | Link to thisIt is illegal to insure against an impossible event that would wipe out the insurance co.
You don't have clew what a smart grid is, how it would work and how much the ridiculous function your ascribe to it would cost.
One month of long term pumped hydro storage would cost 140 cents a kwh.
It simply isn't feasible.
Anti - nuclear zealots generally shill for Big Oil. You are one of the worst examples of Denier, spewing junk science and obviously not believing in the science that says we have less than ten years to solve the GHG problem.
Nuclear deniers don't give a rat's ass about the 3 million people worldwide killed annually by coal pollution having no timely solution to its elimination. They oppose the nuclear solution without cogent argument knowing full well every year you can delay kills three million more.
They are ghouls.
The horrible tragedies in Japan should be responded to by every nation on Earth which has the expertise and resources to do so. The fact is, no place on Earth is immune to natural disasters of that magnitude or greater. Americans must band together to make sure that greedy dirty energy companies can't keep us vulnerable to added threats to our lives and health in order to maximize their windfall profits.
Reply | Report Abuse | Link to thisThe nuclear emergencies and natural gas and oil fires in Japan should be an object lesson, and dire warning, to every nation. This is why it is of utmost urgency to convert the world's energy systems to TRULY clean, safe, abundant, inexhaustible and FREE energy sources, such as Wind, Sunshine, Geothermal Heat, Tidal/River Flows and Hydrogen/Oxygen extracted from Water using electricity from those sources.
If you think massive conversion to clean energy would be "too expensive", I have 2 questions for you:
1) In your cost/benefit analysis, how do you value the lives of nuclear plant radiation victims, coal miners, drilling rig workers, billions of sea creatures and the millions of people who die from pollution-caused illnesses?
2) If we fail to restore and protect the ONLY known natural life-support system in the Universe, how will you justify that failure to your gasping, wheezing Great-Grandchildren, and what do you think the money saved will be worth to THEM?
If Japan's energy came from self-renewing energy sources, there would be no oil and gas fires or nuclear emergencies adding to the other crises they are facing.
seth says, "You don't have clew<sic> what a smart grid is, how it would work.."
Reply | Report Abuse | Link to this============
I've always gotten a big chuckle out of the rabid nuclear proponents here, spewing their incessant propaganda for only nuclear, while degrading every other source of power imaginable.
The fact that you continue to skirt, is that our archaic electrical grid was designed 100 years ago, is vastly outdated and inefficient, and just like the rest of our crumbling infrastructure, should have been addressed years ago for vast improvements. Our electrical grid is 34% efficient, whereas the electrical grid in Europe is 80% efficient and a whopping 90% efficient in Japan.
It makes no sense at all, to continue adding more and more power plants to our current grid, no matter what the energy source is, until we can improve the electric grid that loses 2/3 of ALL power generated!
You have a link for your absurd numbers. I love to see for once some kind of backup from you.
Reply | Report Abuse | Link to thisA conversion from fossil's to clean and green nuke energy would situate a nuke for every 120K population in the US. Not much need for smart grids and transmission upgrades at that point.
1) In your cost/benefit analysis, how do you value the lives of nuclear plant radiation victims, coal miners, drilling rig workers, billions of sea creatures and the millions of people who die from pollution-caused illnesses?
Reply | Report Abuse | Link to thisThere are more people getting struck by lightning than dying of nuclear radiation. Fatal accidents in coal mining and oil drilling are not much higher than in iron mining and geothermal drilling. I'm not sure how atmospheric greenhouse gases can kill sea creatures. About 2 million people die of fossil fuel pollution annually. Smoking kills over 5 million people annually.
2) If we fail to restore and protect the ONLY known natural life-support system in the Universe, how will you justify that failure to your gasping, wheezing Great-Grandchildren, and what do you think the money saved will be worth to THEM?
Finland has higher level of natural radiation than some parts of Chernobyl fall out area. In the Cambrian period, atmospheric CO2 was 20x higher than today and life flourished.
The threats may be exaggerated but yes we have to shift to nuclear fusion and renewable energies.
Well, it's pretty clear that we are not yet ready by a long shot to use nuclear (fission) safely for our needs.
Reply | Report Abuse | Link to thisWe've probably passed 'peak-oil' a decade or so ago.
Coal is impossibly dirty - the technologies for 'clean power from coal' are nowhere near ready.
Fusion power is a long, LONG way ahead (if it ever comes about, and it is safe when it is available).
Renewable energy resources (solar; wind; tidal; combustion of wastes; etc) are way too small for our exponentially growing needs - and the technologies to use them are not ready in in case.
Hydro-electric power - there's not enough of it, and large hydel power stations cause huge devastation of our natural environment.
With all of that known to practically everyone - why is it that we're ducking the real issues?
-- Overpopulation by human beings of planet earth;
-- Greedy overuse of natural resources by human being.
-- Our ruling philosophy that we are the "Masters of the Universe".
When will we ever recognize that the real problem is only the 'human species'?
GSC
Yes we recognize the real problem is the human species. So what's the solution? Make ourselves extinct? Stop using electricity and cars? Go back to the Middle Ages?
Reply | Report Abuse | Link to thisThis is utter crap.... "It means loss of off-site AC power—power lines are down—and then a subsequent failure of emergency power on-site—the diesel generators. It is considered to be extremely unlikely, but the station blackout has been one of the great concerns for decades." Extremely unlikely in New Mexico, perhaps, but an inevitability in Japan, and you don't need to be smarter than 5th grader to figure that out!!
Reply | Report Abuse | Link to thisThis has predictable written all over it. You'd have to be a complete moron to have ever thought otherwise..............
Reply | Report Abuse | Link to thisThe article says:"And the type of accident that is occurring in Japan is known as a station blackout. It means loss of off-site AC power—power lines are down..."
Reply | Report Abuse | Link to this<a href="http://3.bp.blogspot.com/-hSyRvGymSGI/TZ1oXxKQ_WI/AAAAAAAAB7w/HQs4QjohU9k/s1600/FukushimaGrid.bmp" imageanchor="1" style=""><img border="0" height="220" width="380" src="http://3.bp.blogspot.com/-hSyRvGymSGI/TZ1oXxKQ_WI/AAAAAAAAB7w/HQs4QjohU9k/s320/FukushimaGrid.bmp" />(^)</a>
Fukushima Dai-ni was taking power from the grid on march 12th. This means that the substation, in the green circle, was energized. why do we think that all three transmission lines to Fukushima Dai-ichi were not energized?
Here is a link to the picture.
Reply | Report Abuse | Link to thishttp://persistentvegetativestate.blogspot.com/2011/04/tomoku-owned-transmission-lines.html
This has only just reached me. It's interesting to reflect on some aspects with only that much hindsight.
Reply | Report Abuse | Link to thisRM
Nuclear Experts Explain Worst-Case Scenario at Fukushima Power Plant
The type of accident occurring now in Japan derives from a loss of off-site AC power and then a subsequent failure of emergency power on-site. Engineers there are racing to restore AC power to prevent a core meltdown
Scientific American
By <http://www.scientificamerican.com/author.cfm?id=40>Steve Mirsky
March 12, 2011
<http://www.scientificamerican.com/?=japan-earthquake-tsunami>
The Japan Earthquake and Tsunami <http://www.scientificamerican.com/report.cfm?id=japan-earthquake-tsunami>On March 11, a powerful, magnitude 9.0 quake hit northeastern Japan, triggering a tsunami with 10-meter-high waves that reached the U.S. west coast. Here's the science behind the disaster » March 11, 2011
<http://oascentral.scientificamerican.com/RealMedia/ads/click_lx.ads/sciam.com/energy-and-sustainability/1190721684/x81/default/empty.gif/646c7035383032444846634142584439?x>
BOILING-WATER REACTOR SYSTEM: The system's inverted lightbulb primary containment vents below through pipes to a pressure-suppression torus. Once that torus breaches due to overpressure, the secondary containment is all that separates the released radioactive steam from the outside environment. Image: http://www.nucleartourist.com/
First came <http://www.scientificamerican.com/report.cfm?id=japan-earthquake-tsunami>the earthquake, centered just off Japan's east coast, near Honshu. The added horror of the tsunami quickly followed. Now the world waits as emergency crews attempt to stop <http://www.scientificamerican.com/article.cfm?id=nuclear-mishap-or-meltdown-a-matter-of-degree>a core meltdown from occurring at the Fukushima Daichi nuclear reactor, already the site of an explosion of the reactor's housing structure.
At 1:30 P.M. Eastern Standard Time on March 12, American <http://www.nucleartourist.com/>nuclear experts gathered for a call-in media briefing. Whereas various participants discussed the policy ramifications of the crisis, physicist Ken Bergeron provided most of the information regarding the actual damage to the reactor.
"Reactor analysts like to categorize potential reactor accidents into groups," said Bergeron, who did research on nuclear reactor accident simulation at <http://www.sandia.gov/>Sandia National Laboratories in New Mexico. "And the type of accident that is occurring in Japan is known as a station blackout. It means loss of off-site AC power — power lines are down — and then a subsequent failure of emergency power on-site — the diesel generators. It is considered to be extremely unlikely, but the station blackout has been one of the great concerns for decades.
"The probability of this occurring is hard to calculate, primarily because of the possibility of what are called common-cause accidents, where the loss of off-site power and of on-site power are caused by the same thing. In this case it was the earthquake and tsunami.
< That this category of mishaps existed has been evident for at least the 35y of emphasis by the Union of Concerned Scientists, and Amory Lovins, etc. Many expert commentators on the AEC PR 'Reactor Safety Study', organised by Saul Levine of the AEC and fronted by MIT gamma-ray spectroscopist Norman Rasmussen, pointed out that their 'one in a million' slogans assumed common-cause failures to be negligible. The final version, pubd 1975 by the reformed AEC now branded Nuclear Regulatory Commission, persisted in the deceit. But a point ignored is not a point unknown.
So we're in uncharted territory, we're in a land where probability says we shouldn't be.
< Probability theory, properly applied, never said anything of the sort. The NRC kept saying it, and Bergeron continues saying it for them and the industry, but it was always bullshit.
And we're hoping that all of the barriers to release of radioactivity will not fail."
Bergeron explained the basics of <http://www.scientificamerican.com/article.cfm?id=how-to-cool-a-nuclear-reactor>overheating at a nuclear fission plant. "The fuel rods are long uranium rods clad in a [zirconium alloy casing]. They're held in a cylindrical-shaped array. And the <http://www.scientificamerican.com/topic.cfm?id=water>water covers all of that. If the water descends below the level of the fuel, then the temperature starts going up and the cladding bursts, releasing a lot of fission products. And eventually the core just starts slumping and melting. Quite a bit of this happened in TMI [Three Mile Island in Pennsylvania], but the pressure vessel did not fail."
< Why is it so rarely mentioned that the TMI fuel elements could suffer, at most, far less heating from decay of radionuclides than the fuel in a typical reactor, because it had started working only the month before? How long had the fuel in each of the Fukushima reactors been working at high power? Such fuel is intended, for economic reasons, to achieve high 'burnup', i.e. fission at high power for a few y.
Former U.S. <http://www.nrc.gov/>Nuclear Regulatory Commission (NRC) member Peter Bradford added, "The other thing that happens is that the cladding, which is just the outside of the tube, at a high enough temperature interacts with the water. It's essentially a high-speed rusting, where the zirconium becomes zirconium oxide and the hydrogen is set free. And hydrogen at the right concentration in an atmosphere is either flammable or explosive."
"Hydrogen combustion would not occur necessarily in the containment building," Bergeron pointed out, "which is inert — it doesn't have any oxygen — but they have had to vent the containment, because this pressure is building up from all this steam. And so the hydrogen is being vented with the steam and it's entering some area, some building, where there is oxygen, and that's where the explosion took place."
< I trust the relevant grad students are being tasked to estimate how much hydrogen would be needed for the scale of explosion seen on TV - a luminous cloud ≥30m high x ≥10m wide. How much cladding must have reacted with water, as good Mr Bradford mentions, in order for that much hydrogen to have been synthesised?
Bergeron discussed the specific power plant in question, the General Electric design BWR Mark 1. "This is a boiling-water reactor. It's one of the first designs ever developed for <http://www.scientificamerican.com/article.cfm?id=nuclear-reactor-safety>commercial reactors in this country, and it's widely used in Japan as well. Compared to other reactors, if you look at NRC studies, according to calculations, it has a relatively low core-damage frequency. (That means the likelihood that portions of the fuel will melt.) And in part, that's because it has a larger variety of ways to get water into the core. So they have a lot of options, and they're using them now—using these steam-driven turbines, for example. There's no electricity required to run these steam-driven turbines. But they still need battery electricity to operate the valves and the controls.
"So there's some advantages to the BWR in terms of severe accidents. But one of the disadvantages is that the containment structure is a lightbulb-shaped steel shell that's only about 30 or 40 feet [nine to 12 meters] across — thick steel, but relatively small compared to large, dry containments like TMI. And it doesn't provide as much of an extra layer of defense from reactor accidents as containments like TMI [do]. So there is a great deal of concern that if the core does melt, the containment will not be able to survive. And if the containment doesn't survive, we have a worst-case situation."
And just what is that worst-case scenario? "They're venting in order to keep the containment vessel from failing. But if a core melts, it will slump to the bottom of the reactor vessel, probably melt through the reactor vessel onto the containment floor.
< This time it won't need grad students; juniors will do. How much sensible heat is in the molten core? Compare that with the joules needed to melt thru the floor of the primary containment.
< This "issue" arose with the Polittee, Alan Poletti's political committee intended by NZ PM Bolger to make marine-propulsion reactors (which by then were practically all propelling nuclear-armed submarines) acceptable to NZ as they had not been. Poletti was unwilling to concede that, if the core melts, it will then melt its way down thru the bottom of the boat.
It's likely to spread as a molten pool — like lava — to the edge of the steel shell and melt through.
< 'likely', eh? Why not certain?
That would result in a containment failure in a matter of less than a day. It's good that it's got a better containment system than Chernobyl, but it's not as strong as most of the reactors in this country."
Finally, Bergeron summed up the events so far: "Based on what we understand, the reactor has been shut down, in the sense that all of the control rods have been inserted — which means there's no longer a nuclear reaction. But what you have to worry about is the decay heat that's still in the core — that will last for many days.
< As a crude summary for TMI, that might be OK. But did those reactors in Japan start up only last month? I doubt it! Absent the actual records, we have to assume their fuel had been accumulating for years, proportionally to the MW-d energy produced, the radionuclides with half-life >1 y e.g Sr-90 & Cs-137.
"And to keep that decay heat of the uranium from melting the core, you have to keep <http://www.scientificamerican.com/topic.cfm?id=water>water on it. And the conventional sources of water, the electricity that provides the power for pumps, have failed. So they are using some very unusual methods of getting water into the core, they're using steam-driven turbines — they're operating off of the steam generated by the reactor itself.
< Is this a credible guess? To the extent the core has already melted, the channels between the fuel rods are no longer extant for the water to rise up, boiling. And any steam that could still be generated in the reactor vessel would be extremely radioactive, making operation of the alleged 'steam-driven turbines' dangerous for the workers.
"But even that system requires electricity in the form of batteries. And the batteries aren't designed to last this long, so they have failed by now. So we don't know exactly how they're getting water to the core or if they're getting enough water to the core.
< About the time this Mursky was writing, workers were already trying to introduce sea water into one or more Fukushima cores - a sure sign the 'proper channels' were no longer open.
We believe, because of the release of cesium, that the core has been exposed above the water level, at least for a portion of time, and has overheated. What we really need to know is how long can they keep that water flowing. And it needs to be days to keep the core from melting.
"The containment, I believe, is still intact. But if the core does melt, that insult will probably not be sustained and the containment vessel will fail.
< Correct - at last.
All this, if it were to occur, would take a matter of days. What's crucial is restoring AC power. They've got to get AC power back to the plant to be able to control it. And I'm sure they're working on it."
< They were indeed; brave workers like those at Chernobyl. But to what effect? I seriously doubt the AC power brought in could do much good if any. I disbelieve that the primary coolant pumps, even if supplied with the thousands of kW AC needed, could circulate the coolant to much effect thru a seriously damaged core.
< I even wonder whether those workers were cynically sacrificed to large radiation doses in order to stage a "we are doing something" act.
L. R. B. Mann M.Sc Ph.D
applied ecology
22a Ardern Ave.
Stanmore Bay, Whangaparaoa 0932,
NEW ZEALAND
(9) 424 0808
http://www.kuratrading.com/HTMLArticles/writings.htm
The article ends with the importance of restoring AC power. We have had a second quake, a 7.0, which had a brief grid outage of 50 minutes, meaning it was a "protective" outage, triggered automatically. On March 11th, Daini was taking power from the grid by midnight. This suggests that the grid at Daiichi was also energized by that time, since they are both connected to same substation (see wikipedia).
Reply | Report Abuse | Link to thisThe previous commenter questions Bergeron's impartiality. I question his accuracy on this point, assuming he was guessing as to this fact - which is a crucial one, and so far, unsubstantiated.
Bergeron says "station blackout" is extremely unlikely. If he is to be the expert, why is the story of "station blackout" (his specialty) not a part of the story worthy of interest? The grid is working now. How was it fixed? Who fixed it? And what did happen to the 13 diesel generators. How many would be needed to power all the necessary equipment? Where were they located? Where was the fuel? Was the entire problem related to a decision to run electric cables in underwater tunnels?
Reply | Report Abuse | Link to thisThis quote is from an ABB article on Transmission and Distribution system efficiency: (http://www04.abb.com/global/seitp/seitp202.nsf/c71c66c1f02e6575c125711f004660e6/64cee3203250d1b7c12572c8003b2b48/$FILE/Energy+efficiency+in+the+power+grid.pdf)
Reply | Report Abuse | Link to this"It is possible to calculate what this means in dollar terms by looking at the difference between the amount of electric energy generated and the amount actually sold at the retail level. According to data from the Energy Information Administration, net generation in the US came to over 3.9 billion megawatt hours (MWh) in 2005 while retail power sales during that year were about 3.6 billion MWh. T&D losses amounted to 239 million MWh, or 6.1% of net generation."
That doesn't add up to 38% efficiency. There are improvements available in T&D, but not 62%.
I think the schematic on page 1 of the article is incorrect, It does not show the concrete part of the primary containment. One of the purpose of the primary containment is to hold the melted fuel. A steel pressure vessel will not be able to do this.
Reply | Report Abuse | Link to thisIf we are to continue operating with dangerous technology in plants with significant public consequences, we need to rethink our design philosophy. We should insist that any and all failure possibilities be contained. That is to say there should be zero tolerance for any possibility of failure regardless of the cost. From this point of view the GE-Toshiba design has several weaknesses.
1. The suppression pool (torus) is not contained in the primary structure. Cause of a radiation leakage in reactor #2.
2. The containment vessel should have passive control rods at its bottom to neutralize any molten fuel.This will prevent thermal spikes.
3. The zirconium cladding should not rupture under stress.
4. The zirconium cladding should be designed for spent fuel storage in pools of water without containment.
5. There is no design feature to protect against natural disasters such as earthquakes and tsunamis. For example Skyscrapers are mounted on rollers and dampers for earthquakes. The San Onofre plant has a 30 ft. high wall for Tsunamis. If black outs are so critical, the cooling water equipment and generators should have been protected.
6. There are no strict rules for adopting fail safe complete shutdowns when any of a list of symptons of failure is exhibited. Too much was left in the hands of Tepco once the first reactor failed. In my opinion, that should have required the complete shutdown of all the plants. Management would never act against their own financial interests without a strict directive from the regulatory agency.
wingnut, you write: That doesn't add up to 38% efficiency. There are improvements available in T&D, but not 62%.
Reply | Report Abuse | Link to thisI do not understand your math. Where does the 38% come from and where does the 62% come from?