>I have worked in a plant where I had half a critical mass in this hand, barehanded and dressed in street clothes, and half in this hand, wearing a lab coat, and I’d put this half in a pocket on this side and this half in a pocket on this side and walk down the hall. If those two ever got together, there’d be a blue flash. They never got together because I was between them.
There's "our design docs are photos of whiteboards" normalization of deviance and there's whatever the hell this is. Absolutely bonkers that there wasn't a demon core-like incident.
I got to see Cherenkov radiation once on a high school class trip with only water between me and the blue glow!
Being a teenager I asked “what would happen if I jumped into the reactor?”
The researcher (this was a medical and research reactor) laughs and says “well, if you just jump into the water and splashed around we’d have hell to pay with filling out an incident report to <something important sounding, I forget>, but physically you’d be fine since the water shields you from the radiation. If you did a swan dive down toward the glow your skin would all melt off before you got to the reactor” maybe he was just saying this for effect but it’s always stuck in my head that water is a really, really good insulator against radiation.
> water is a really, really good insulator against radiation.
Absolutely. There is this[1] horror story about a diver who was doing maintenance in a transfer pool next to two spent fuel pools. After he was done with the work he found an unidentified object at the bottom of the pool and was instructed to put it in his tool basket. The object was a broken piece of irradiated reactor component. They realised that something is very wrong when the diver was lifting the basket out of the water and the area radiation monitors started to alarm, so they lowered the basket back into the water.
On the 10th slide of the document there is a diagram showing the water's shielding as a function of distance. At 1.4 meters there is no dose they can measure while they measure extremely high doses at centimeter distances.
I think you need power densities much higher than the shielding of an MPRR you saw to melt skin away. You'd probably get some bad radiation sickness and maybe even die instantly within a short radius, but not have the Hollywood skin melt.
"""
So, as far as swimming safety goes, the bottom line is that you’d probably be ok, as long as you didn’t dive to the bottom or pick up anything strange.
But just to be sure, I got in touch with a friend of mine who works at a research reactor, and asked him what he thought would happen to you if you tried to swim in their radiation containment pool.
“In our reactor?” He thought about it for a moment. “You’d die pretty quickly, before reaching the water, from gunshot wounds.”
"""
I have worked in a plant where I had half a critical mass in this hand, barehanded and dressed in street clothes, and half in this hand, wearing a lab coat
So they were only wearing a lab coat on one half of their body? I'm confused.
One lab coat, one pair of jeans. Half core in lab coat pocket, half core in jeans pocket, to prevent the lab coat pockets from coming into contact if they were in opposite pockets of the lab coat.
What's wrong with design docs being on a whiteboard? Not every company has time to painstakingly draw pretty UML diagrams in Figma when there are features that need to be built!
A whiteboard is a great tool to quickly iterate towards a shared understanding of the design at that point in time.
But if you take a photo of it and think you're done with documenting your design, you A) lose most of the context of the decisions that were made to arrive at that design. And B) have ensured that your documentation will get outdated and become useless pretty soon. You've basically decided not to have design documentation but filled yourself into believing that you do.
If you are serious about documenting software design to help future developers understand the system, you really do need those diagrams in a digital, easily updateable format and with textual explanations of the underlying decisions. And if doing that seems more work than it's worth, do it anyway, just with less details.
You joke, but I once worked on a team where nobody was able to point me to any coherent high-level documentation of what the system actually _did_... they all just walked around referring to it by some proprietary name as though you were some type of misinformed dunderhead for not understanding them. It took two hours of a manager talking and filling up a wall-sized whiteboard for me to discover that it was just a hideously over-engineered amalgamation of a CDN and document repository. If they'd had a diagram, README, or had even been able to give me the one-sentence overview then I suspect that the project's head count and productivity would have looked much different.
This is all to say that if you 1) invent novel terminology for things that already exist, 2) don't document anything, and 3) run your team like a high school clique then you never have to worry about finding yourself out of a job. Thankfully my current gig has loads of video training and an interactive dictionary for proprietary terms in an attempt to combat this.
And all the silicon valley layoffs, likely filled to the brim with people that conscienciously documented their replaceability for their employer, will look at that "high school clique" and remark "that's how you deal with sociopathic management".
Yeah, eventually management will nuke the whole division, but at least it provides those with jobs a bit more runway.
How much of the bemoaning of such adversarial tactics by engineers themselves is simply annoyance at what it causes them at their jobs, or the fact they have internalized pro-management propaganda?
This has nothing to do with alpha rays (which are helium nuclei), but with neutrons, and fast neutrons are much less prone to generate a fission than thermal neutrons, so having a moderator in between your fissile material parts reduces the amount of fissile material you need to achieve criticality. That's how nuclear reactor work, by the way. And this is also what happened to John Bistline on the 4th of June 1945 at Los Alamos.
Edit: in fact the first ever recorded criticality accident ever recorded involved the water in the body of a scientist (Otto Frisch), though the water was acting as a neutron reflector here, and not as a moderator.
With one half in the pocket and the other in hand (while it's being placed into the "safe" other pocket) nothing prevents the latter from going unintendedly close the first.
Interestingly, some accounts of the yet to be fully released FBI report on the gun in question state that the FBI investigators caused the weapon to fire without pulling the trigger because the gun was in such poor condition, that one of the times when they pulled back the hammer, some part of the gun broke and it fired. Apparently, it was in such poor condition that the gun did NOT fire on some of their attempts even when they actually did pull the trigger.
So their public statements so far are that the gun was not possible to fire without pulling the trigger -- as long as all the parts were intact (which they were not by the end of testing.)
What if two people walk down the hall doing the same thing in different directions? ... Oh I forgot my slide rule ... !#FLASH#! ... what was that!? Oh shit.
Half joking. Is the material and spatial separation of a lab coat enough to prevent a reaction between two lumps of plutonium of sufficient combined critical mass? It might be since it's so bad at penetrating anything solid, but I don't know.
> It might be since it's so bad at penetrating anything solid
This isn't the case!
Plutonium 239 is relatively safe, merely an alpha emitter which is what you're talking about. But that isn't where the danger comes from. The danger comes from the Plutonium 240, which is present as a contaminant in all plutonium weapons cores. Plutonium 240 spontaneously undergoes fission, releasing neutron radiation which is very penetrating. If you bring two halves of a core together, neutrons from the spontaneous fusion of Pu-240 can cause a chain reaction; this is the reason gun-type bombs don't work with Plutonium cores; they give off too much neutron radiation and would react prematurely if you tried to build a Plutonium bomb like that.
> Is the material and spatial separation of a lab coat enough to prevent a reaction between two lumps of plutonium of sufficient combined critical mass?
Plutonium is very pyrophoric, especially dust, powder, fines, shavings, etc.
Plutonium metal likes to form a hydride layer that rapidly oxidizes in the presence of any water; this oxide then vigorously reacts with water. Plutonium fires have occurred at several national labs in the US, including two incidents that contaminated the Rocky Flats site.
Forget demon cores and use as an elaborate poisoning agent, the stuff is a huge conventional safety hazard.
Edit: my vote for actual most dangerous substance known to man, though, goes to chlorine trifluoride[1]. It will vigorously react with sand, bricks, asbestos, and other stuff that is usually reliably inert.
Wow. That might be the most reactive chemical that can be stably synthesized and kept at normal temperatures and pressures.
I wonder if the Aliens movies got their idea for the blood from this stuff.
> There’s a report from the early 1950s (in this PDF) of a one-ton spill of the stuff. It burned its way through a foot of concrete floor and chewed up another meter of sand and gravel beneath, completing a day that I'm sure no one involved ever forgot. That process, I should add, would necessarily have been accompanied by copious amounts of horribly toxic and corrosive by-products: it’s bad enough when your reagent ignites wet sand, but the clouds of hot hydrofluoric acid are your special door prize if you’re foolhardy enough to hang around and watch the fireworks.
If I recall the detailed story, the workers sued the government for work hazards and they...conveniently added fluoride to toothpaste right around the time.
It's not even the dose here, it's the reactivity of the chemical bonds. Sodium fluoride (alkali-halogen) bonds are a lot more stable than halogen-halogen bonds. And a Chlorine Trifluoride bond? Woah.
> Of ingested plutonium, 99.99 percent will be excreted in a day or two.3 The experimenters had to figure out a way around this.1 Their solution was reprehensible.
>
> In 1950, Manhattan Project doctors injected 18 people, ages 4–69, with plutonium without their knowledge.
"From 1945 to 1947, 18 people were injected with plutonium by Manhattan project doctors. [...]
The government covered up most of these radiation mishaps until 1993, when President Bill Clinton ordered a change of policy and federal agencies then made available records dealing with human radiation experiments, as a result of Welsome's work. [...]
The committee issued a controversial 1995 report which said that "wrongs were committed" but it did not condemn those who perpetrated them. The final report came out on October 3, 1995, the same day as the verdict in the O.J. Simpson case, when much of the media's attention was directed elsewhere." [0]
"The US government settled with the victims' families, paying $400,000 per family." [1]
>The committee issued a controversial 1995 report which said that "wrongs were committed" but it did not condemn those who perpetrated them. The final report came out on October 3, 1995, the same day as the verdict in the O.J. Simpson case, when much of the media's attention was directed elsewhere." [0]
Even if the verdict had not been announced that day, the visit of the Pope would have overshadowed the release of a 1,000 page advisory committee report which itself was only a slightly expanded investigation of an incident that had already been covered by a congressional committee report nine years earlier.
Some people use the coincidence to imply that the administration tried to bury it, but it was actually an open-government initiative by the Clinton Administration meant to highlight their pursuit of injustice and had been on the calendar for weeks, with the printing of hundreds of copies of a 1,000 page book, the scheduling of a White House ceremony, and guests having been flown in from all over the country.
And evidently they lived longer than the median for their industry colleagues as well as the general population. So a couple of things could contribute: the healthiest of fit people were chosen, their jobs drove them to be healthier than their peers or somehow ingesting the stuff had a positive effect on them. The last one is dubious but without evidence to the contrary should be considered.
The last one is called "radiation hormesis", the opposing theory in which there is no safe level of ionizing radiation is "linear-no-threshold" (focusing only on the "no threshold" part). The middle ground is a threshold model in which low levels are hypothesized to do nothing for or against one's health.
I believe this date is inaccurate; the injections of Plutonium happened in 1945 through 1947. The Manhattan Project was disbanded in 1947. Those experiments might have continued, but they wouldn't have been under the Manhattan Project in 1950.
There is one substance for which an apple-sized quantity could (appropriately delivered) kill all of humanity: The naturally occurring organic substance known as botulinum toxin, which has an estimated LD50 of about 1.5 ng/kg.
"It is, of course, extremely toxic, but that's the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water—with which it reacts explosively."
I’ve seen the blogpost before, but the Wikipedia article is great.
From Wikipedia:
> This oxidizing power, surpassing that of oxygen, causes ClF3 to react vigorously with many other materials often thought of as incombustible and refractory. […] In one particular industrial accident, a spill of 900 kg of ClF3 burned through 30 cm of concrete and 90 cm of gravel beneath.
Two things: First, the idea of burning (not melting!) through 1.2m of what is effectively stone is wild. Second, somebody had 900kg of this stuff in one place?!
The article actually mentions it (not by name). But I think that the difference between the Demon Core and your average chunk of Plutonium (non-critical) is not well understood by most people. Which is why people are afraid of all sharks- A single frame of reference for something that's multi-faceted.
There’s certain things that it’s better to “incorrectly” have people be scared of than trying to be precise. Just like the “treat every gun as loaded” rule - for those not directly involved in nuclear science, treat all nuclear vessels as demon cores and remain decently far away.
I don’t know who Nader is, but if he said in 1975 that plutonium, or really anything at all, could kill 8 billion people then he was lying. We can be certain of this because there were only 4 billion people alive back then, so it was literally impossible to kill 8 billion people.
Or maybe I’m just not in the mood for this article right now.
That link says Nader said "Any use of plutonium, a tiny 0.2 micrograms of which has given lung cancer to animals, must be viewed with utmost caution".
> Plutonium-239, the product of the nuclear fuel cycle used for the construction of nuclear weapons, is one of the most toxic substances known to man. It is also a substance which occurs rarely in nature and is almost entirely man-made in the nuclear fuel cycle. One microgram of plutonium-239 ingested into the lungs is capable of causing lung cancer. Approximately, one 8,000,000th of a pound of inhaled plutonium has caused lung cancer in animals. Thus, when effectively dispersed, a much smaller quantity of plutonium than would be needed for a nuclear bomb could necessitate the evacuation of dense urban areas.
There's the 8 billion.
We know that quotes get mis-attributed to more famous people.
My guess is that Krieger's comment got rephrased and mis-attributed to Nader, who was, after all, talking about the same topic.
tl;dr; version: "Walter Cronkite, a revered American journalist, told us in 1977 that Plutonium is the most dangerous substance known to man. That statement was widely believed, and widely repeated. But that statement is false. Unless you are really stupid about the critical mass, Plutonium has a quite innocuous MSDS ( https://en.wikipedia.org/wiki/Safety_data_sheet ), and is almost impossible to poison a person with."
The Real Problem: Walter Cronkite's statement was true, but in a big-picture contextual and somewhat poetic sense. The fraction of humanity with any reason to care about the MSDS safety of plutonium is ~0%. The fraction of humanity living in (in 1977, and often since) a world which seems threatened by a hellish large-scale nuclear war is ~100%. Making the "MSDS Argument" to people in the latter group is often a good way to convince them that you're an obnoxious and uncaring little jerk, eager to show off that he read a science textbook at school.
Analogy: Read a bit about the lethality of WWI battlefields in Europe, how many millions died on them, and how traumatized European society was by that war. Imagine that someone from that era claimed that the most dangerous substance known to man was the special steel alloy used to make artillery gun barrels and machine gun barrels.
Or the "WW1 technology" angle, the example that comes to mind is the invention of the Haber process for ammonia production. This allowed mass production of fertilizer (saving many from starvation) but also enabling mass production of explosives (again with many peaceful civil applications) which enabled industrial scale wars like WW1.
For something that debunks other stories, it's not terribly accurate. The Slotin and Daghlian accidents were not bomb assembly and not "bringing together enough Plutoniom". They were about toying with an almost-critical bomb core and neutron reflecting materials.
In both cases, familiarity bred contempt and a minor slip-up caused the thing to go critical. Same casual attitude as "carrying half a critical mass on each side in a lab coat pocket". What if once you forget and hang up the coat with the pieces still in the pockets?
Only 4,000 drownings per year in the USA. Radon is estimated to cause 21,000 lung cancer deaths per year. So definitely not, at least in the modern era.
Those radon numbers, however, are largely based on the same LNT calculations of risk criticized in this article. Most of the guidelines are based on questionable epidemiology with very small sample sizes (when excluding the major confounder, smoking) and results in the typical 1.1-1.2 odds ratio for a relatively rare disease (in non-smokers, of course.)
If you want to get particular, those 'radon deaths' are actually caused by the various radioactive decay products of radon, rather than radon itself. Particularly, radioactive isotopes of polonium, lead, etc.
I think we’ve all heard stories of senseless deaths of people who’ve died of dihydrogen monoxide poisoning. Even more damning of the modern factory farming complex, did you know that dihydrogen monoxide is by far the most commonly used industrial solvent in not only industrial but also agricultural processes, used on a scale that would absolutely shock the average person. The rice and bottled water industries are examples of especially egregious offender in this respect. I think you’d be hard pressed to find a factory or farm anywhere not using it. They put it in our food, the water we drink, and even more shocking, they aren’t required by US law that it be labeled as one of the ingredients, so people can’t even make an informed decision about whether or not to avoid it!
Personally, I’ve been on a multi day abstention from dihydrogen monoxide in my diet. I’ve been drinking only grain alcohol instead and based on the burning and tingling sensations I’ve been feeling I’m fairly certain my body is finally purging all the toxins I wasn’t able to when I was addicted to dihydrogen monoxide. I’ll make sure to post another update as I gather more data.
If you’d like to learn more about this important subject that’s gone under the radar for too long, I’ve attached the MDS [0] about dihydrogen monoxide. We really need to ask our congresspeople to pass regulations and fund research investigating the potential harms of dihydrogen monoxide before it’s too late.
For fictional substances known to man, I would pick red matter (from Star Trek, a drop could turn a planet or star into a black hole) or Ice9 (from Cat's Cradle, a form of solid water that would turn all water in contact with it into Ice9). A very small mass of them is enough to kill all life in a planet.
I suppose the next one in the scale is grey matter, that with a bit more than a Kg could kill all life in the planet in the right conditions.
Some theorized variations of https://en.m.wikipedia.org/wiki/False_vacuum_decay are essentially an unstoppable bubble of complete destruction (not even known physics remains intact) spreading in every direction at the speed of light.
> A number of theories suggest that cosmic inflation may be an effect of a false vacuum decaying into the true vacuum. The inflation itself may be the consequence of the Higgs field trapped in a false vacuum state.
Basically the Big Bang may be younger than the matter in the universe.
Anything is possible in fiction of course, but it is hard to take a story seriously that uses a material whose properties would be contrary to the laws of physics as a plot device. Either you have a material so unstable that galaxies would never form or something thermodynamically impossible or both.
tl;dr the article is refuting 1970s (and earlier) era claims about how lethal plutonium is by citing anecdotes and pointing out the maximum toxicity requires a totally unrealistic delivery mechanism.
As an aside, I believe Plonium-210 [1] is widely viewed as more toxic than plutonium. The only thing more toxic than that is fentanyl and that's only if you're a cop [2].
Anyway, so this is just a pro-nuclear power piece. Do with that what you will. I'll just point out that with incidents like the East Palestine derailment you will often find that the companies responsible have their liability limited by law. In the case of nuclear power plant operators, their potential liability is strictly limited by the Price-Anderson Act [3].
The press regularly repeats claims that a relatively small amount of fentanyl seized in a drug bust or something would be enough to kill a large fraction of the population of United States. Such claims may be wildly overstated however because the LD50 of fentanyl in humans is unknown. The estimated value is basically a guess.
> Thing with FOOF is you'd notice your bones dissolving almost immediately.
I'm not sure about FOOF, but that's definitely not the case with hydrofluoric acid. With hydrofluoric acid, depending on the concentration, burn symptoms can take several hours to manifest, luring victims of accidents into a false sense of security and causing them to delay seeking treatment.
Wikipedia states her blood mercury level at 4 mg/L with 0.2mg/L in the urine (i.e. getting excreted at a decent rate) five months after the alleged incident.
Ignoring exponential decay, in five months at one liter a day she would have shed 30mg (so actual numbers were way higher).
Is it a typo/error or does this actually mean she was killed by way more mercury than a few drops through the glove?
The actual amount was was probably in the tens or so of milligrams. "A milligram" is a slightly hyperbolic way of saying "a very small amount", down in the small-fractions-of-a-gram level.
I forget that not everyone on the Internet is aware of English idiom.
Money is one of the most powerful tools for enabling cooperation ever devised, perhaps only rivaled by spoken and written language.
Like all tools, mass cooperation through money is a double edged sword. It's behind every war, every genocide, every enslavement. It's also behind every medical treatment, every piece of food in the grocery store, every act of emergency aid.
Without money, yes, we wouldn't have large scale devastation and consciously inflicted suffering. But we would also all still be living in huts and caves regularly dying of dysentery and starvation and would be lucky to see 2-3 of our 12 children make it to adulthood.
> It's behind every war, every genocide, every enslavement.
There are examples of war and enslavement that pre-date minted currency. Non-barter forms of exchange probably allowed for a specialist warrior class to develop though.
If I had to choose a radioactive isotope to imbibe, tritium would be my top pick. Unlike many actinides it isn't a "bone seeker" and is readily excreted alongside all the other water that passes through us. Realistically you drink alot of water and beer and you'll be fine. Also its decay products are very low energy and gentle compared to most.
> if you have a small piece of it, it is rather harmless given it is an alpha emitter and can be stopped via single sheet of paper.
Thing with alpha emitters is, if you get it on you the outer layers of skin will stop it before it does much damage. If you get it *in* you, where there's living tissue way closer to the surface like in your mouth or your lungs, it'll give you an absolute rip-roaring tumour.
Most adults stopped putting strange things in their mouths a long time ago.
But agree, Alpha emitters are a problem if taken internally, which is why i stated breathing/drinking tritium increases cancer risks.
there is not a clear line between "alpha exposure" and "rip-roarding tumour"... See "nuclear medicine", "radioactive tracers" etc for examples of where alpha emitters are intentionally given to patients.
Yes,-ish but look at the isotopes used for radiotracers in medicine - they typically undergo beta decay and their half-lives are in the order of minutes, mostly, with phosphorus having a half-life of about a fortnight and sulphur about three months.
The author appears to be subtweeting anti-nuclear activists. But I don't think waste is the issue most people worry about when they think about nuclear these days. Meltdowns are the real fear, and rightfully so.
Just build the plants well, in a safe part of the world (no quakes, tidal waves etc), and have some well paid, high I.Q people running them. They'll be fine. Nuclear power is such a gift to humanity. As much power as we need, and comparatively little waste. But no, some people fear it, so we have to build endless bullshit windmills, and strip mine Africa for the elements required for solar panels (branded as "sustainable energy", though both just go into landfill when they reach the end of their life).
Yeah I mean, look at that article. High IQ people carrying around subcritical chunks of plutonium. But it’s OK mum, I put them in different pockets! Isn’t physics amazing!
What do you mean I picked up the wrong coat?
“Just build the plants well” is the civil engineering version of “No True Scotsman”.
I'm admittedly not a nuclear engineer - but I hear a great deal about how much modern nuclear plant design has advanced since the days of Three Mile Island and Chernobyl, and that our modern designs would not be susceptible to such catastrophes. Assuming this is somewhat true (I am just assuming that) we are erroneously allowing the ghosts of those terrible old events to stop us from investing in modern, safe nuclear energy.
At least France get a decent amount of base load energy for the strip mined Uranium. And I'm not defining operators of nuclear plants with serious accidents as low IQ - my point is that there are lots of dangerous, complicated industrial plants that are run safely, and there is no reason that the same can't be true for a nuclear power station.
There's "our design docs are photos of whiteboards" normalization of deviance and there's whatever the hell this is. Absolutely bonkers that there wasn't a demon core-like incident.