Speaking specifically to this picture
https://www.atomicarchive.com/history/trinity/afterwards.html
In: 685
That picture is from a few months later. They certainly would have been exposed to some radiation, but most of the contamination would have been blown away by the wind by then. Also, I don’t think they had as good of an understanding of fallout as we do now so probably wouldn’t have returned so soon these days.
I’ve never seen an assay of how radioactive ground zero was for trinity but my assumption would be two things. First they weren’t hanging around for that long and second it probably wasn’t nearly as radioactive there as people think. I also didn’t see anywhere in that picture saying how recently the detonation occurred, the most dangerous time for radiation would be right after detonation. The most active fission products will decay the fastest as well so waiting a few days can drop the activity significantly.
All that said, just because they weren’t getting radiation sickness it doesn’t mean it was a good idea. Radiation exposure can increase the probability of cancer years down the road even if there are no symptoms at the time of exposure. The U.S. exposed a lot of people to radiation from testing the atomic bombs and resulted in a lot of unnecessary cancers. They ended up creating the radiation exposure compensation act as a way to help people who suffered from those mistakes.
While the earlier bombs were probably fairly “dirty” relative to modern nuclear weapons, there is this idea that an atomic weapon renders the ground around it dangerous for all lifeforms for centuries. This is where fear rather outstrips the reality. The most dangerous time would be a few days/weeks at most. After which the most dangerous by products either decay and/or get scattered fairly thinly across a wide area.
Radioactivity and radiation is something we encounter naturally all the time (blame the sun probably) and the human body doesn’t “melt” or “mutate” when exposed to mild radiation.
Trinity created radiation hazards similar to the bombings of Hiroshima and Nagasaki – most of the danger was concentrated in the first few hours. The difference is that civilian victims had *no idea* what they had been subjected to, how or where to hide from fallout, for how long, etc.
In contrast, Los Alamos scientists didn’t *immediately* drive into ground zero. They sent crews in lead-lined Sherman tanks to do an initial survey, wore dosimeters, etc. Some of those tankers did receive significant doses, over ten rads, but those were several times too small to cause ARS.
Dose limits weren’t understood at the time. The project had a few criticality accidents, two of them fatal, and had seen ARS but they didn’t have enough data to predict what a lethal short-term dose would be. That data would come from Hiroshima and Nagasaki.
Oppenheimer died of cancer, but we know enough now to say it was far more likely the result of smoking than his atomic career.
Trinity did cause harm to civilians. We know that roughly a hundred cattle were burned by fallout; the government purchased 88 of them as compensation – and people lived and worked in the same places. The fallout from that test was never properly mapped and victims never compensated. This is partially because it was the world’s first public radiation emergency, nobody knew what to do – and mostly because of military secrecy.
In short, they were careful and were lucky to have been careful enough.
There are two ways to get radiation during an atomic detonation: 1) the detonation itself 2) radioactive contamination.
The essentially run away nuclear reaction of an atomic bomb releases radiation into the surrounding areas. But, once the nuclear chain reaction stops, which is very soon after it starts, radiation from this source ceases. Oppenheimer hiding in control bunker far away protected him from mo t of that radiation.
But, the nuclear chain reaction 1) throws radioactive fuel away from the explosion 2) radioactive fuel breaks down into other radioactive elements 3) things like soil become radioactive.
It is these bits of radioactive stuff that cause problems because they last a long time and release radiation over time.
The worst thing that can happen is a bit of radioactive stuff gets stuck inside you and it keeps hitting you with radiation over time damaging cells and causing cancer.
So, unless you get a lot of radioactive stuff on or in you, the problem is largely a long term problem. Which it possibly was for people who lived nearby.
A short visit to Trinity after months, being sure to clean the dust off you… should mostly be OK.
Btw, Oppenheimer did die of cancer. But probably from smoking too much.
Most of the radiation after the blast is only a problem if ingested or inhaled and even then a short exposure is not likely to be a short term problem for a healthy adult.
The people that die of radiation sickness after an atomic bomb are usually close enough to the bast to get neutron radiation and gamma rays in fatal doses and/or are exposed to high levels of short lived radioactive isotopes in their food and water in the days after the bomb. Neither of those applied to people visiting the trinity site, they really only risked a higher rate of cancer years later.
[removed]
The photo was taken in early September 1945, on a press “safari” to the Trinity site orchestrated by General Groves in order to try and disprove assertions that were being made about possible long-term contamination effects of radioactivity at Hiroshima and Nagasaki. So it was a deliberate propaganda photo of sorts.
The Trinity test did make the area immediately around the detonation intensely radioactive at first. Samples were taken from the test site in a lead-lined tank, and even that had limits to how close it could go.
But the drop-off in radioactivity from nuclear fallout is very steep. [Within 14 hours](https://remm.hhs.gov/RemmMockup_files/dose-rate-decay.png) of a nuclear explosion the radiation levels will have dropped to about 1% of what they were when it immediately went off.
Let us imagine that at 1 hour after the detonation, the test site radioactivity was a massive 10,000 R/hr. Exposure to 500 R is often a fatal dose for people. So that is radioactive enough to kill you in 3 minutes.
The simple rule for calculating radiation decay in fallout is called the Wigner-Way t^-1.2 law, and it basically is: R = D x t^-1.2 , where R is the “current” dose rate, D is the dose rate you are starting with, and t is the number of hours. So if D is 10,000, and t is 48 hours, then R = 96 R/hr, or 1% of the original. That’s still a lot of radiation! 100 R will give you radiation sickness, but probably not kill you.
OK, so what if we wait a week? Then it’s down to 21 R/hr, which is still not something you ought to be exposed to (it’s way higher than background), but it’s more in the “might raise your chances of cancer in the long run.”
The photos in question were taken about 60 days after the detonation. So that gets you down to about 2 R/hr. That is… still hot-enough that today, if you had a choice, you’d probably want to give that a pass. For comparison, the EPA doesn’t let people working in the nuclear industry get exposed to more than 5 R per year. The general public is not supposed to pick up more than 0.025 R per year beyond their normal, natural radiation dose. So 2 R/hr is what we would today consider to be pretty hot. If you are there for an hour, that is a low-enough dose that you wouldn’t expect any short-term health issues, and if a small number of people were visiting it only for a bit, you wouldn’t expect to be able to detect any meaningful increase in cancers. However, if you had people _living_ there, especially in large groups, it would be a bad idea.
All of the above assumes we know the starting radiation (10,000 R/hr) which is not a terrible assumption for the order of magnitude around the base of the tower. But we don’t really know that for sure. But there would potentially have been areas near ground zero (perhaps a bit downwind of it) with levels at that order of magnitude. So even though it is somewhat arbitrary, it’s not _totally_ arbitrary to go with that number for a weapon of this size, and an area like ground zero. But I would emphasize this would be the most intense part of the fallout — we are working from the worst case parts. Most of the fallout downwind of ground zero would be a lot less intense.
You’ll notice in the photos if you look carefully that they are wearing little booties. They are trying to avoid tracking the contaminated dirt back home with them — it’s one thing to visit it and then leave, it’s another to visit it, get contaminated stuff on your shoes, and then take it home where you (and your family, your kids, your pets) can inhale it.
The tricky thing about fallout is that it contains a lot of different elements, many of which are radioactive versions of elements your body wants and needs (or similar-enough to them that your body treats them like them), and so they can get inside you and sit there for a long time, radiating you over the long-term. So Strontium-90 is a nasty, medium-lived isotope in fallout that your body (and the ecosystem) treats like calcium, and so can get embedded inside your bones. So the raw exposure from visiting the site isn’t necessarily the total exposure at all.
Anyway the (shorter) answer is that because of the time passed, the radiation was a lot lower than what it was when the bomb went off, but it was still higher than most people who are telling you that it was safe probably appreciate.
I think they both died of cancer years later, no?
Just on Smoke Back in the day firefighters had a 8x relative risk of dying from lung cancer – smokers at the time 2-3 x (cardiovascular risks were much higher at the time) – my point inhaling smoke, any smoke causes lung cancer
Latest Answers