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Excessive Radiation Inside Fukushima Fries Clean-Up Robot (gizmodo.com)
"A remotely-controlled robot sent to inspect and clean a damaged reactor at Japan's Fukushima nuclear plant had to be pulled early when its onboard camera went dark, the result of excess radiation," reports Gizmodo. "The abbreviated mission suggests that radiation levels inside the reactor are even higher than was reported last week -- and that robots are going to have a hell of a time cleaning this mess up." From the report: Last week, Gizmodo reported that radiation levels inside the containment vessel of reactor No. 2 at Fukushima reached a jaw-dropping 530 sieverts per hour, a level high enough to kill a human within seconds. Some Japanese government officials questioned the reading because Tokyo Electric Power Company Holding (TEPCO) calculated it by looking at camera interference on the robot sent in to investigate, rather than measuring it directly with a geiger counter or dosimeter. It now appears that this initial estimate may have been too low. Either that, or TEPCO's robot is getting closer to the melted fuel -- which is very likely. High radiation readings near any of the used fuel are to be expected. Yesterday, that same remotely operated robot had to be pulled when its camera began to fail after just two hours of exposure to the radiation inside the damaged reactor. Accordingly, TEPCO has revised its estimate to about 650 sieverts per hour, which is 120 more sieverts than what was calculated late last month (although the new estimate comes with a 30 percent margin of error). The robot is designed to withstand about 1,000 accumulated sieverts, which given the failure after two hours, jibes well with the camera interference. This likely means that the melted fuel burned through its pressure vessel during the meltdown in March of 2011, and is sitting somewhere nearby.
I speak from experience on the latter.
It's clean, safe, and too cheap to meter.
You are welcome on my lawn.
There are radiation resistant electronics but it isn't something you'll find off a shelf. Plus if its a hot neutron source pretty much no electronics they I know of are going to work properly.
Still one would expect they had a more accurate and cost effective way to measure the level of radiation before sending an expensive robot in.
Why, I read on Slashdot just the other day that a few remote controlled bulldozers could have Fukushima cleaned up in a month and that tree-hugging anti-growth enviros should shut their pieholes about that accident.
sPh
In this case the "radiation" is the emission of high-energy neutron particles. Neutrons will run into anything *... and when they do, they transfer a ton of their energy into whatever they hit... causing "damage cascades" as atoms get tossed around (Wikipedia has a decent animation here: https://en.wikipedia.org/wiki/... ).
That atom-scale damage adds up after a while... causing material failure... regardless of the type of material.
For instance, inside of a reactor all of the steel holding all of the fuel in place is constantly bombarded... leading to all sorts of effects like radiation induced swelling and embrittlement.
In humans the primary issue is when those neutrons hit DNA / cells and damage them. It actually happens to us all day long from radiation around us... but our bodies can deal with a certain amount. Too much damage though... and your body can't cope any more.
In robots / electronics the issue is much the same. The neutrons run into _everything_ and degrade it. More sensitive pieces (like camera sensors) will degrade rather quickly while larger components (like structural steel) will most likely be fine for long periods of time.
* The probability that a neutron will hit a certain type of atom is called a "cross section" (XS) and is an _extremely_ well studied phenomenon. You can look at some here: https://www.nndc.bnl.gov/sigma... for instance, this is the probability for a neutron running into Hydrogen: https://www.nndc.bnl.gov/sigma...
We need a radiation cleanup robot cleanup robot.
I'm a good cook. I'm a fantastic eater. - Steven Brust
Or rather, excessively more expensive once reality demonstrates the inadequacy of ElCheapo risk management and risk avoidance. Interestingly, cost comparisons never include these factors. If humanity were not so stupid as a group, the refusal of all insurers to ever cover nuclear reactors should have been a really large hint. And we have not even started to tackle the problem of dismantling non-melted down reactors and storing spend fuel. Fun for the next few 1'000 or so generations to come!
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
At those intensities, measuring things becomes very hard. Geiger counters only work up to pretty low radiation rates. Dosimeters need exceptionally heavy shielding to not immediately go black in the conditions there. Actually seeing how long the camera lives may be the best currently available method that fits on a robot.
Humanity has basically no experience with radiation levels this high.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
Gamma rays break down the crystalline structure of things like the chips. Even low-level radiation will wash out a camera, but about 10-25Sv for "long" periods of time will have some effect, 650Sv pretty much instantly destroys everything, even things like the metal the robot is constructed out of will eventually become harder and more brittle as the atoms get knocked out of the structure (eg. if someone suggested pneumatics, plastic, rubber and metals would also deteriorate).
Custom electronics and digital signage for your business: www.evcircuits.com
You would think very wrong. This was, incidentally, already discovered at Chernobyl at much, much lower radiation levels. All the robots sent from the west failed pretty soon. The whole nuclear power industry is built on the assumption that such accidents do not happen and hence it is not at all prepared for them. That makes it exceptionally unprofessional from an engineering point of view.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
How will space colonization ever takeoff if the Earth is not made uninhabitable?
**Life is too short to be serious**
https://www.stripes.com/news/16-us-ships-that-aided-in-operation-tomodachi-still-contaminated-with-radiation-1.399094
You don't know what you're talking about again, Kendall.
+1. What aircraft are exposed to are mostly gammas and a few heavy ions, not neutrons (alongside massive amounts of gammas as well). There's nothing close to neutrons in terms of causing damage, they'll penetrate almost anything and then activate it so you get the whole mix, alphas, betas, and gammas inside the sensitive devices that you're trying to protect. You can make electronics that's somewhat resistant to radiation, but it can't do much against neutrons. In any case all the rad-hard stuff is designed for space/military use, and that's gammas, not neutrons (and accompanying alpha, beta, and gamma).
There really isn't any easy way to do this. One approach I guess would be to have all the control electronics a long way from the robot and only basic actuators and sensors on the robot itself. However, video is still control electronics...
You laugh, but tubes aren't affected by ionizing radiation.
Only the State obtains its revenue by coercion. - Murray Rothbard
Random suggestion--
Use a trailing fiber optic pickup, with the actual CCD and robot controller hardware OUTSIDE the reactor.
Similar in concept to the imaging system used for laparoscopy.
In this case, the "mobile" portion of the robot is made using the "more radiation resistant" larger discrete components, with a fat data cable and fiber optic line dragging behind it, leading to the actual logic controller portion of the robot, parked outside.
That would help with costs, and service life of the robot. (Expensive controller hardware stays outside the reactor, only the driver part needs to be discarded as radioactive waste, and the imaging sensor array is not inside the reactor.)
Humanity has basically no experience with radiation levels this high.
There are higher radiation levels inside an operating reactor. And humanity deals with spent fuel pools with similar level of radioactivity all the time. The difference is that those situations have the spent fuel sealed inside fuel rods and safely shielded by lots of water rather than spread out across the floor, in the air, etc.
In other words, the morons screaming hysterically about nuclear energy are in large part being enabled and encouraged by the morons responsible for designing and implementing it.
Rather like web security, then.
In other words Yes folks, the fuel is indeed outside of the reactor core.
Let's, for a moment, consider what words were spoken inside the TEPCO media relations meeting;
This is exactly the kind of slimy trick the Nuclear Industry PR would use to downplay evidence of fuel being outside of the reactor, maybe I've been napping however I've not seen the headline Evidence of Nuclear Fuel Found outside of Fukushima Reactor Core anywhere. I'm just supposed to be comfortable that it's inside the containment as if it's no big deal that it didn't melt *INSIDE* the reactor where it should be.
M: Susan, make sure the by-story runs that it is *inside* the containment, we need to make sure the fans have a counter argument. People, we're running with the robot broken down story and that we think it might have kinda possibly run into a tad bit of radio stuff,, we have to get on top of this before the mainstream get a hold of the news. Susan, where are those overalls!
This article from the Japanese daily contains the video feed from the robot. Above the hole you can see the base of the reactor pressure vessel. Your statement seems a trite summation considering the evidence discovered.
It's perfectly reasonable to be angry about the incompetence that led to this disaster, what's weird is trying to say it's no big deal. The international community who shares the coasts of the pacific ocean will suffer the consequences of this over a very long time. This is what a big deal is.
I don't see any justification for supporters of nuclear energy to play the same morally superior dogmatically skeptic attitude they have had over the last decade anymore, this is an INES7 scale accident. Information is available now, and people can read so what need is less downplaying so we can figure out the nature of the mess the nuclear industry has left us and where these 3 cores are.
Evidence of reactor fuel found outside of the Fukushima reactor is the information and the nuclear industry is very carefully avoiding any further criticism.
My ism, it's full of beliefs.
Actually, a lot of the resistance against nuclear energy is people who are (rightfully, it turns out) distrustful of the nuclear industry.
Let's face it, we've been fed a diet of PR, if not outright lies from the very start about the risks and costs of nuclear energy. By now, anything that comes out of an industry shill's mouth can be assumed to be untrue by default.
"I know I will be modded down for this": where's the option '-1, Asking for it'?
It's an onion of bullshit opposed by bullshit, though. Nuclear is fundamentally rather cheap and rather clean, using sane designs (not designs where it fucking melts into oblivion if it doesn't have constant active cooling, jesus christ what is wrong with those people), and using reasonable accounting based on rational pollution opportunity cost comparisons.
That is true *fundamentally*. In practice, nuclear has to spend so much on safety as to cause less than 1/100th the deaths of fossil fuels and even then people are still completely terrified over non-events (from a harm to human life standpoint) like Three Mile Island, people talk ominously about half-lives without ever once mentioning phrases like "Love Canal" or "Centralia" as points of comparison, economical designs are opposed by blowhards like Carter, etc.
It's worth focusing on alternatives mostly because there's too much bullshit to cut through, too many misconceptions and assholes protecting their jobs to make nuclear reform realistic. Unfortunately, there's not an ideal drop-in replacement for nuclear, particular not for larger megaproject sizes that could put a serious dent in pollution whilst simultaneously raising capacity and lowering costs in anticipation of the electric automobile revolution. Maybe they could drop a huge geothermal plant in Yellowstone... yeah, I'm sure the Greens would be perfectly OK with that, if it meant stopping global warming.
Yes, but coal is shit and oil is shit and they both kill people all the time. And also cause global warming, contaminate fish with toxic heavy metals, etc.
The argument against shitty nuclear designs is (for the sane and knowledgeable among us) thus more about cost than risk to human life, and since you're talking about already-built stuff then most of the costs are already sunk and if there's no easy migration path you're probably better off simply spending more effort on backup equipment and contingency plans. This is completely ignoring the public relations aspect of nuclear, which I've no idea how to manage and at this point probably isn't fixable.
But yeah, you've fully grasped one side of the coin: "Nuclear experts are full of shit."[1] The other side of the coin is the comparison to alternatives, and speculating how much cheaper nuclear could go if we reduced certain safety measures[2] while still keeping the death toll lower than fossil fuels, which is something virtually no one bothers doing. Nuclear being expensive remains a self-fulfilling prophesy as long as you refuse to take off the blinders.
1. This is true of most experts, but particularly experts in controversial or highly politicized fields who have grown insular, defensive and/or polarized over time.
2. Not relaxing the safety measures to prevent catastrophic "everything is now fucked" incidents like Fukushima so much as allowable radionuclide release during normal operation, perhaps allowable radiation exposure levels adjusted to end up being as dangerous as working in a coal mine, etc. Also, there's some common sense shit like designing reactors and sites that can store all of their waste on-site that no one seems to be talking about, but is perfectly doable in principle and would at the very least least nerf one very common complaint.
Then that's just about everything.
Yes, you got it in one.
Wind disaster: wind turbine catches on fire. Maybe falls over and kills a cow. We don't have to have humans climb them any more until they actually need work, because we are now inspecting them with drones.
Solar disaster: solar installer falls off roof, probably dies. This is very sad and we should integrate the solar into a metal roof which lasts longer and has better failure modes and is fireproof rather than retrofitting onto old houses with crappy roofs and no preinstalled roof anchors.
Oil disaster: ugh. oil is a disaster. too valuable to burn, let alone spill all over ducks.
Coal disaster: mining it is a disaster. burning it is a disaster.
Nuclear disaster: potentially renders large area uninhabitable by humans for long periods, even if it doesn't kill anyone directly it substantially increases cancer risk for large numbers of people.
I mean, holy shit. Can we please, please, pretty please account for the worst case?
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Agree. You could have individual air lines or hydraulic lines to each wheel actuator. Send the fluid one way for that wheel to spin forward, the other way for reverse. Then a minimum robot is just 2 drive cogs, then a fiber optic line for vision and a second fiber optic line for light. No reason it couldn't sit directly next to the molten fuel and work indefinitely. Have an internal chamber and a scintillator tube with a fiber optic line that can relay an image back. From the light intensity - how often the tube is getting stimulated - you'd be able to measure the radiation level. Probably have to use special tubes made just for this.
Where "everything" is a light water reactor such as the BWRs and PWRs of this period, it certainly looks like that's the case. That isn't universally true though; the graphite-moderated Magnox and AGR designs of the same era can passively cool entirely by CO convection. The downside is they have a lower power density, but the only failure I've read about was a partial melt of a single Magnox fuel rod after a blockage in a single channel interrupted the airflow.
530 sieverts per hour is an insane level of radiation.
Since 1 Sv = 100 rem, we're talking about 53,000 REM per hour, a level that would indeed kill you dead in under a minute.
For scale and comparison, the average dental x-ray image exposes you to only about 2 or 3 millirem.
So....530 sieverts per hour is like getting ~26,500,000 dental x-rays in an hour.
Just cruising through this digital world at 33 1/3 rpm...
Your non-chalant attitude about radioactivity downplays the risks
It does not. It *compares* them. And nuclear power has been responsible for far less death and suffering even if we include Chernobyl. Without Chernobyl, we're deep into 'more people have been killed by pillow fights' territory.
A meltdown and loss of control can cause it to spread wide as it has with Fukushima.
And Fukushima has been a *financial* catastrophe. It has not been a public health one compared to the other risks we accept all the time with fossil fuels.
Radioactivity has toxicity properties in its own class
Just pure white noise. I understand that sentences like these (which are being posted by many people, not just you) are meant to be persuasive, but it's just a complete non-starter. I don't care if it's different. Toxic heavy metals can be terrifying enough, thanks. "Different" doesn't matter. Severity does. And the numbers I've seen show pretty convincingly that nuclear isn't nearly as bad.
Wouldn't fiber optics get degraded by the radiation? It's a thick optical mass and while we can manufacture thick optical masses that are perfectly clear (a.k.a. fibers), this is what radiation does even to thin ones.
Ezekiel 23:20