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foone Jul 17
Replying to @Foone
See, photographic film is basically a bunch of silver halide crystals suspended in gelatin. These crystals have complex chemistry that causes spots on their surface to turn metallic if they absorb light... or gamma rays.
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foone Jul 17
Replying to @Foone
so the film was getting spots and fogging from absorbing radiation from their cardboard containers. The radiation was very weak and not really dangerous to users, but film is designed to be very sensitive to light, which makes it very sensitive to other forms of EM radiation too
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foone Jul 17
Replying to @Foone
This is why EVEN TO THIS DAY (I literally saw one of these signs yesterday), the TSA has signs about putting your undeveloped film through the x-ray machine. X-rays are another type of EM radiation, and sensitive enough film will be fogged by them.
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foone Jul 17
Replying to @Foone
So as WW2 had just ended and nuclear weapons were still pretty secret, Kodak kept quiet about their discovery, although they had communicated with Los Altos to figure out what had happened. And they installed air samplers to detect fallout and prevent this happening again.
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foone Jul 17
Replying to @Foone
Which, guess what, it did. In January 1951 the US government started testing in Nevada, with the Operation Ranger series of tests. These were the first tests inside the US since Trinity.
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foone Jul 17
Replying to @Foone
And few days later, Kodak's HQ in Rochester, N.Y. (1,600 miles/2500 km away!) got a massive snowstorm, and their fallout detectors reported that the snow was 25 times more radioactive than normal.
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foone Jul 17
Replying to @Foone
This was a secret 1-kiloton test. No one was supposed to know, but Kodak did. They filed a complaint with the Atomic Energy Commission and the National Association of Photographic Manufacturers.
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foone Jul 17
Replying to @Foone
The AEC's reply was basically "Sorry about that, but we can't tell you where the tests are going to be (They're secret!) and we can't stop the wind from blowing" And Kodak's reply was: YOUR TESTS ARE GOING TO COST US MILLIONS IN RUINED FILM, AND WE HAVE LOTS OF LAWYERS.
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foone Jul 17
Replying to @Foone
So the AEC compromised: Executives of Kodak and other film companies would get Q Clearance (an above-top-secret clearance needed for nuclear weapons matters) and be told ahead of time where tests would be and where the fallout might go/did go.
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foone Jul 17
Replying to @Foone
So during the cold war, Kodak and other film manufacturers had access to highly secret information (the kind the Soviets would (literally) kill for), in order to ensure their film wouldn't be contaminated by fallout from US tests.
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foone
The main reason we know about this is because in 1997-1998 there were a series of senate hearing on this, because while it's very nice that the government was so worried about damaging the photographic industry, they didn't provide similar warnings to people living downwind.
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foone Jul 17
Replying to @Foone
Fallout dissipates very quickly: If people living in affected areas had been told to evacuate or stay indoors, their radiation dose could have been severely limited. But for reasons of secrecy, they weren't told.
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foone Jul 17
Replying to @Foone
So this decision probably ended up killing quite a few people over the years due to increased cancer rates. And not just people living in the immediate area of the nuclear tests: Farmers weren't told either, and it's not known to what degree crops & livestock were contaminated
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foone Jul 17
Replying to @Foone
And it's definitely the case that people far from directly downwind were affected: A research project in the 50s-60s collected baby teeth from the St Louis area and measured how much Strontium-90 was in the teeth.
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foone Jul 17
Replying to @Foone
Strontium-90 doesn't exist in nature in any significant quantities and easily absorbed into the body and used in place of calcium. Baby teeth are an easy way to measure exposure in humans, since bones tend not to be discarded as often.
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foone Jul 17
Replying to @Foone
It can cause various sorts of cancers including leukemia, as it's got a relatively short half-life and stays in the body for a long time, depending on where it gets deposited.
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foone Jul 17
Replying to @Foone
The preliminary results released by the Baby Tooth Survey in 1961 showed that the amount of Strontium-90 in children was elevated compared to pre-1950, and was increasing, with the later children having the most exposure.
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foone Jul 17
Replying to @Foone
And keep in mind, this was in St. Louis, Missouri. All the above-ground tests were in Nevada and New Mexico, over a thousand miles away.
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foone Jul 17
Replying to @Foone
A later study found that children born after 1963 had 50 times the Strontium-90 in their teeth than children born prior to 1950.
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foone Jul 17
Replying to @Foone
It was actually these results that lead to the US, UK, & USSR signing the Partial Nuclear Test Ban Treaty in 1963. This banned above-ground test detonations of nuclear weapons. From then on, they'd all be underground.
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foone Jul 17
Replying to @Foone
Since then plenty of other nations have signed the treaty, with the total being 126 as of 2015. Naturally most of those countries don't have nuclear weapons so it doesn't really affect them.
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foone Jul 17
Replying to @Foone
But a few notable nations have not, and they're notable because they do have nuclear weapons: China, France, and North Korea.
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foone Jul 17
Replying to @Foone
Of those, only China and France have actually violated the PTBT (or would be violating it had they signed it). North Korea's 6 tests were all underground.
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foone Jul 17
Replying to @Foone
China has done 23 above-ground tests, and France did 57. For comparison, the US tested 231 non-underground weapons and the USSR did 229, with the UK doing 21.
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foone Jul 17
Replying to @Foone
BTW, a side note with the PTBT: It's what ultimately killed realistic scifi's incredibly awesome and terrible favorite spaceship engine: PROJECT ORION!
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foone Jul 17
Replying to @nyrath
You'll have to check out 's great resource Atomic Rockets for all the details, but the tl;dr is that they were studying a way to launch a spaceship using lots of small(ish) nuclear explosions.
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foone Jul 17
Replying to @Foone
The basic idea is that you build a spaceship with a big shock absorber on the back and keep tossing nukes behind you and setting them off. Yes, that's SLIGHTLY batshit insane, but on the other hand you really can't beat it for sheer power.
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foone Jul 17
Replying to @Foone
Until you get into Star Trek level Future Tech engines using antimatter or whatever, Project Orion is about the most powerful "engine" you can imagine. It makes most rocket engines, even the giant ones used on the Saturn V, look about as powerful as a super-soaker.
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foone Jul 17
Replying to @Foone
The USAF 10M Orion design was going to have 360 1-kiloton devices and another 138 half-kiloton devices. During acceleration they'd be setting them off about 1 every second. And this is a small design.
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foone Jul 17
Replying to @Foone
The fun thing about Orion is that it doesn't scale down very well, but it sure as hell scales up. You've got enough power at your disposal to build very large vessels and shove them directly to where-ever you need to go.
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foone Jul 17
Replying to @Foone
Need something the size of an aircraft carrier launched and in orbit of Saturn within a few weeks? Orion will get you there.
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foone Jul 17
Replying to @Foone
the other fun thing about orion is that it's most powerful on the ground. It's utterly amazing for launching cargo into orbit, which is exactly where you don't want to be using it.
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foone Jul 17
Replying to @Foone
The USAF was considering modes where they would launch it up 90-kilometers using chemical rockets, and only then activating the drive, but this loses most of the big advantage of Orion's ridiculous amount of thrust.
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foone Jul 17
Replying to @Foone
But they were obviously worried Orion even before the PTBT killed it. The public was unlikely to be very happy with a space ship made of explosions, and you can imagine how much the USSR would freak out at one of these being built, let alone launched.
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foone Jul 17
Replying to @Foone
In any case, the final bit of weirdness about Kodak is that they had a nuclear reactor. No, really. And not like a small research reactor running on relatively safe un-enriched uranium, NOPE! they had one running of weapon's grade uranium.
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foone Jul 17
Replying to @Foone
It was a Californium Neutron Flux Multiplier. It takes a core of Californium-252 (Kodak used other reactors to create it) which generates neutrons at a rate of around 100 million to 10 billion a second, then runs it past small plates of highly enriched uranium to multiply them
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foone Jul 17
Replying to @Foone
They were using this to check materials for purity and to test neutron imaging, a technique much like x-ray imaging where high-energy particles are sent through a subject and their "shadow" is measured.
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foone Jul 17
Replying to @Foone
They built it into a specially dug basement at Building 82 in Rochester, New York, installed in 1974. The main chamber was only accessible (while running) by a pneumatic tube, so samples would be sent in and then automatically retrieved remotely by operators.
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foone Jul 17
Replying to @Foone
They had three and a half pounds of highly enriched uranium, and it was safely removed when they decommissioned it in 2007.
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foone Jul 17
Replying to @Foone
I love this fact because it's such a silly out-of-place thing. Like, how many thriller novels and shows like 24 have had bad guys getting their hands on enough material to make a dirty bomb by stealing it from a research lab, or a crumbling ex-soviet state?
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foone Jul 17
Replying to @Foone
Nobody ever builds one by breaking into their local film company.
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