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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.
If someone could figure out how to make tech that could survive in such environments. Aircraft have to deal with more radiation than normal, as do spacecraft. Something that survived for say a day in such an environment might survive for a very long time in an aircraft and work without errors, which is equally important..
I speak from experience on the latter.
That is why we need replicants. They can withstand anything, even the C-beams that glitter in the dark near the Tannhäuser Gate.
When the copyright term is "forever minus a day", live every day like it's the last.
It's clean, safe, and too cheap to meter.
You are welcome on my lawn.
I'm not sure I want anyone handing you a hammer so you can speak from more experience on what a hammer can smash, but personally, I like smashing walnuts and pecans with hammers.
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
you might even live for a day
That's comforting.
Slashdot, fix the reply notifications... You won't get away with it...
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
They need to go old school and replace the tech fancy robot with a remote using hydraulics to make it move, and a mirror /periscope system to see what it sees. Fiber optic perhaps? You can manipulate the valves with cabling to avoid using anything electric.
_ _ _ Go for the eyes Boo! GO FOR THE EYES!
Explodes lol. Spoken like an anti-nuke that knows absolutely nothing about nuclear power.
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
Do dangerous technology carefully. And here is a hint: If you cannot get an "unlimited" insurance, it is probably not a sane idea to do in the first place. Insurers are smart, very experienced with disasters and want to earn money. If they do not offer, that means the rate they would have to charge would be so outrageously high that it could not be paid.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
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.
https://en.m.wikipedia.org/wiki/Radiation_effects_on_optical_fibers
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.
Displacement damage isn't a problem in this case, it accumulates over years. The primary concern there is radiation embrittlement of pressure vessels, standard 316 stainless contains nickel which captures neutrons and forms an unstable isotope of nickel with an even larger capture cross-section, which decays into iron and (eventually) helium. So you end up with voids created as displacement damage from the neutrons that fill up with helium, which is not a good thing in a reactor vessel. Still, that takes years of continuous exposure to high neutron flux, not hours or minutes.
The issue here is that zoo of other particles that the neutrons create as they pass through matter: prompt fission gammas, capture gammas, decay gammas, inelastic scattering gammas, bremsstrahlung, and so on and so on, as well as alphas and betas due to neutron activation. Conventional rad-hard devices aren't going to help you much there.
You laugh, but tubes aren't affected by ionizing radiation.
Only the State obtains its revenue by coercion. - Murray Rothbard
I wonder how much it would cost to replace the parts damaged by radiation, instead of getting a whole new robot?
If you want to sit there with a screwdriver and disassemble something that's taken an absorbed dose of 500-1000 Sv, be my guest.
Radiation is, by definition, the transfer of energy through space. So yes, a sufficiently high flux will cause an electronic gizmo to fail just as surely as baking it in an oven would, provided the radiation is of a nature that is absorbed by the kind of matter you find in electronics.
Here we're concerned about neutrons.
Neutrons can penetrate deeply in to materials, and when absorbed by a nucleus can generate gamma rays. This damages materials in multiple ways, such as pitting, swelling, cracking, and microscopic crystal structure changes which are particularly bad for semiconductors. Even passive components such as wire insulation, carbon composition resistors and mylar capacitors begin to fail if you expose them to, say, 10x the neutron radiation intensity you'd use to kill a tumor.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
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.
Semiconductors work by having a "tipping point" after which they become conductive. High energy electrons (beta particles) are way higher than the bandgap of basically any semiconductor. They will cause the migration of ions embedded in the semiconductor that enable it to be semiconductive.
Additionally, you have things like hot neutrons, and gamma rays. Hot neutrons will cause fission type interactions with the doping atoms embedded in the semiconductor, changing them into 'something else', and releasing lots of secondary particles in the process. Gamma rays are high energy photons, and contribute to migration in the semiconductor.
All in all, these all cause the semiconductor to disintegrate, and stop functioning.
That's why I suggested keeping all those sensitive parts OUTSIDE of the reactor containment vessel, and using a really fat, electrically shielded data cable and a fiber optic line attached to a dumb manipulator that goes inside instead. That way the electronics are shielded by the reactor containment walls, and however much dirt is between it and the exposed core material.
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.
Let's do a cost comparison as you suggest. Here's a graph of nuclear power generation over the last 45 years. Generation has been about 2300 TWh per year for the last 20 years. The 25 years before that ramped up roughly as a triangle, so call it 2200/2 = 1100 TWh per year average.
This gives us a total of 73,500 TWh generated by nuclear power over the last 45 years. 20*2300 + 25*(2200/2) = 73500.
Using a global average electricity price of $0.20 per kWh, this is $14.7 trillion dollars worth of electricity generated by nuclear over the last 45 years.
Chernoby cleanup costs (current and future) are estimated to total $235 billion, Fukushima is estimated to be around $200 billion. Three Mile Island was about $1 billion. These are the only major commercial nuclear accidents in history, and their total cost is estimated to be $436 billion.
$436 billion / $14.7 trillion = 0.02966. Or about 3%.
So the cleanup costs for nuclear accidents is about 3% of the price of the electricity nuclear generates. Or 0.6 cents per kWh. This is so "excessively more expensive" that it would cost the average American home less than $8/year. (Average American home uses 10,812 kWh/yr * $0.12/kWh average electricity price * 20% of electricity produced by nuclear * 3% cleanup cost = $7.78/yr.)
Insurers refuse to cover nuclear because of how statistics work. The more incidents there are, the narrower the bell curve and the more confident you can be about predicting how many accidents will happen. A 10d50 will be much more likely to yield a result near 55 than a 2d50 is to yield a result near 51. Consequently, even though their long-term mean is almost the same, a bookie will give you better odds on the 10d50 because it's more predictable and thus harder for them to lose money on it.
Nuclear plants generate massive amounts of power. You need about 10 coal plants to equal a single nuclear plant. Several thousand wind turbines. Consequently you need much fewer nuclear plants to meet your energy needs compared to these other power sources. So even though statistically nuclear plants are safer than other power sources (mean accident rate is lower), their small number means there's larger uncertainty about how many accidents will happen. Insurers compensate for this by erring on the safe side (for them) and charging much higher rates. e.g. If there are 100 nuclear plants and the mean says 1 will suffer an accident in 30 years, the insurer may err on the safe side and charge a premium based on, say, 2 or 3 accidents, just in case they get a bad die roll. Whereas if there are 1000 coal plants and the mean says 10 will suffer an accident in 30 years, the insurer can be much more confident that even if they get a bad die roll, they can charge a premium assuming only 15 accidents and still make money.
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.
Not a lot because they were all quietly closed down after TMI or upgraded to solve various problems (mostly instrumentation).
Oh, moving the bar from obviously dangerous to the level of just being a lot less than ideal? In that case all of them even the AP1000 reactors under construction (1980s design with tweaks). There's nothing really more modern than the Fukushima reactor at the scale required for commercial electricity generation in the USA at the moment.
"not designs where it fucking melts into oblivion if it doesn't have constant active cooling, jesus christ what is wrong with those people"
It's not easy or even necessarily better to do it another way. Having a gravity activated emergency cooling system isn't foolproof either, especially in a country like Japan where earthquakes are the biggest risk. Massive lateral forces can jam mechanisms, so it may be better to have a non-moving system with pumps and battery backup, for example.
The problem with new designs is that so far they have all failed. Too expensive, didn't work, turned out to be worse in practice... So just saying we need better tech implies massive investment in unproven technology with a poor outlook, at a time when renewables are showing excellent and relatively safe returns.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
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. As an aside some of the really old stuff shut down just after the TMI incident was incredibly scary. In hindsight it was a lucky accident to have. It generated so much fear because the thing was so poorly instrumented that it took a very long time to work out what the hell was going on so the media was full of speculation for weeks.
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.'"
This isn't a surprise to anyone. What do you think is contaminating all that water they pump out of the basement? Why do you think you can measure a dose outside near the plant? The evidence overwhelmingly showed it was a meltdown and the fuel escaped the reactor and some has even escaped containment. The latter is the real problem - a better containment design, and they wouldn't have all this contaminated water because it wouldn't leak like it does. Nor would it have contaminated the surrounding town.
Not a lot because they were all quietly closed down after TMI or upgraded to solve various problems (mostly instrumentation).
Anyone who's idea of process safety is upgrading instrumentation shouldn't be working in process safety.
Nothing is solved, the likelihood of some incidents have been reduced. Nothing more.
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.
Well, only if you consider 50 times the normal thyroid cancer rate being harmless. But what would I know, I only had a girlfriend from Belarus who had her thyroid removed thanks to Chernobyl.
"It's such a fine line between stupid and clever" -- David St. Hubbins, Spinal Tap
We'll yes and no - one could tether the robot with a fiber optic cable. Keep the stuff on the robot pure optical and put the sensors somewhere else away from the neutron radiation.
When one looks at the AP1000 design, while more safe than current reactors, there are still problems. Several systems have to function for cooling to occur, even though you do not need a generator. If a cooling line is physically destroyed, coolant will not get where it needs to go, for instance.These things also have a tank that has to be filled after a few days, assuming the coolant lines from the tank to the reactor are not damaged. There are valves that have to be activated by control systems to open the emergency cooling system, so you assume those systems will work, that the control systems are physically accessible and have not beenn destroyed by damage, that any electrical control systems are not damaged, etc. When dealing with catastrophic damage, all of these safety systems could be rendered moot and nonoperative. So these designs are filled with all sorts of assumptions and still could completely fail and lead to a meltdown.
Your non-chalant attitude about radioactivity downplays the risks, Radioactivity has toxicity properties in its own class, unlike say arsenic, it releases radiation which constantly bombards surrounding tissue should it accumulate over time in your body. A meltdown and loss of control can cause it to spread wide as it has with Fukushima.
Neutrons don't usually cause double strand breaks in DNA. Alpha particles are much more trouble; then betas, then high energy gamma, then lowly neutrons!
Also,
Viewing the nuclear cross sections can be done with the even more powerful tool JANIS
https://www.oecd-nea.org/janis...
Alphas are indeed much more trouble. But also, alphas can be blocked by a piece of paper, while neutrons just keep on sailing through for a good while. My point is that alphas are not a problem in the real world unless you ingest or inhale an alpha-emitter––that is the only way they can cause serious trouble – be being inside you and wrecking whatever cellular matter they are sitting next to.
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...
It doesn't take years if the flux is high enough and the components are sensitive. Direct neutron damage really can be a problem for electronics.
You are definitely right about all the high energy secondary particles. They cause a whole heap of problems for electronics (including signal spikes etc).
My point really was that there's nothing special about the interaction between radiation and biological intitities (as the original poster was implying). Neutron radiation (including secondary effects) will damage non-biological materials just as well as biological.
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.
The small little thing you overlook (convenient, as you are obviously do not have effective intelligence) is that a single, average-sized nuclear fuel dump that leaks its contents into the atmosphere is quite enough to sterilize the planet with regards to higher life-forms. If you compare normal operations contamination, of course nuclear looks clean. But a coal power plant that blows up is not more toxic than one that works and the same goes for the resulting waste. Not so at all with nuclear.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
All the iron ever produced is sufficient to kill every human, cow, and horse now alive, if distributed one bullet per heart. So what? It isn't distributed that way, and most stored nuclear waste isn't going to float around in the atmosphere even if it does escape, because it's heavy.
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With the greatest possible respect because I'm sure that you are very good at something, have you considered that those items you listed are not of an appropriate size to drive tiny little robot parts and that it would be difficult to control dozens of them at once?
Not only can you buy them in lots of different sizes (those are just some I came up with quickly) but I reject the notion that you need a lot of fiddly fine control. I'm still stuck on my tentacle idea. Wait, that sounded wrong. But anyway, it would use the opposite of fine control. You could operate it manually.
What you suggested is a cool idea, I'm not knocking that, just the dream that someone at TEPCO could say "make it so" and a hydraulic robot gets built in under a year.
Not only am I proposing no such thing, but this has been going on for half a decade now. And frankly, that there is no solution for doing this already is just one more reason why nuclear power is unacceptable. They don't have plans for what to do when it fails!
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"