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MICHAEL SHORT: So as a quick review
of all the different biological effects,
we've pretty much taken it up to here.
We've explained the physical and chemical stages
of what happens when radiation interacts
with mostly bags of water with some solutes in them, better
known as organisms at dynamic equilibrium.
Everything from the sort of femptosecond level, ionization
of water almost certainly, because that's
most of what biological things are,
to the formation of many, many, many, many, many different
radiolysis byproducts eventually that end up as just a few
that we care about, the longer-lived radiolytic
byproducts that will then diffuse away
from the original damage cascades
and go on to eat something else, likely DNA or something
that you don't want to get oxidized or chemically changed.
We talked a little bit about radiolysis in reactors
and how you can actually measure it directly
which was only done really a few years ago which is pretty cool.
Just to remind you of this experiment,
there's a tiny high-pressure cell
of high-pressure, high-temperature water.
There is a foil sample with a very thin region and protons
firing through it, so that they both irradiate the sample
and induce radiolysis in the water at the same time.
And this way, you can test the effect of radiolysis
in the water here versus just plain, old, high-pressure,
high-temperature corrosion here.
And the results are pretty striking,
where you can clearly see the boundary where the proton
beam was as well as the increased thickness
of the oxide and corrosion layer formed when radiolysis
is turned on, so to speak.
We went through DNA damage, and we ended with pseudoscience.
So I want to bring up a couple--
no, we don't have time for that.
But we spent the last 15 minutes of class railing
against pseudoscience and making sure that you check your facts,
but we pointed out a number of things
wrong with some of the studies.
So aside from just that guy misreading everything
on that entire blog, of the studies that you felt
weren't very convincing, what do you remember about them?
Some of those studies were totally fine, but some of them
were not.
AUDIENCE: The ones with particularly small sample
sizes.
MICHAEL SHORT: That's what I was hoping someone would say.
Yeah, the case study of four women
who got breast cancer in the pocket
where they held their cell phones, four, right?
Or in a study of 29 humans, 11 of them got brain tumors here.
It's pretty easy to cherry pick small amounts of data.
I did want to say that just because radio frequency
photons aren't ionizing, doesn't mean they can't hurt you.
If you've ever-- no, no one's ever been inside a microwave.
I wonder if anyone's ever felt the effects
of an external microwave being by something like this,
the active denial system.
One of my favorite weapons ever, because it doesn't actually
permanently hurt anyone.
It just heats up the outer layer of your skin.
It fires these non-ionizing photons at RF frequency
and effectively makes you feel like you're on fire.
So if there's a whole mess of troops charging at you--
let's say at the DMZ from North and South Korea--
all you've got to do is turn on this thing,
and they all think they're on fire,
because their body is sending them signals that I'm on fire.
And then you turn it off, and they're OK.
So no loss of life, no permanent damage,
a lot of maybe psychological, but whatever,
you can't see that.
AUDIENCE: Active denial.
MICHAEL SHORT: Active denial system, great name for it,
isn't it?
Yeah, I think non-lethal weapons are really the way
of the future is just make it unpleasant to engage
in warfare, and people probably won't.
But then no one has to get hurt, which is nice.
But then onto the sources of data, because like Sarah said,
sample size is everything, especially when you're
trying to figure out, are small amounts of radiation
bad for you?
This simple question hasn't really
been answered suitably yet, and that's because, thank god,
we don't have enough people exposed
to small but measurable amounts of radiation
to draw meaningful conclusions from this data.
I think that's a good thing, is if we were certain about
whether small amounts of radiation,
like one millisieverts, could cause cancer,
then there would have been millions or billions of people
exposed, and so it's kind of a good thing that they weren't.
But the sources of this data, the first source
was radium dial workers, like you may have heard of,
the folks that would lick the paint brushes with glow
in the dark radium watches.
They ended up setting the first occupational limit for dose,
because they were the first large group
to be exposed to radiation in a controlled setting.
Things like uranium miners, radon breathers, better known
as us, but especially folks that smoke anything.
Medical diagnostics, so anyone that gets a medical procedure,
you can follow up with them to find out what's, let's
say, the extra incidence of cancer and figure
out, if you have a high-dose medical procedure,
does it induce secondary cancer down the line?
But like we said last time, down the line is the key here.
I'd take a whole bunch of radiation
now, if it was going to save my life now, and maybe
make it messed up in 20 years.
Because then you get 20 more years of life
or however long you get.
And then from accidents, survivors
of the atomic bombs, not just the folks at the epicenter,
but in the whole fallout regions and nearby, as well as
nearby nuclear accidents and the criticality events
like the demon core that you guys analyzed on the exam.
Luckily, there aren't a lot of those, either.
But they were pretty severe, the ones that got exposed.
And speaking of accidents, has anyone ever heard
of the Kyshtym disaster?
This is the third-worst nuclear accident
that we know of in history, after Chernobyl and Fukushima,
and worse than Three Mile Island,
because Three Mile Island was an almost accident.
There was some partial melting of the core.
There was almost no release of radioactivity.
And the definition of a nuclear accident in the public sense
is release of radioactivity.
There's actually two quantities that folks
in PRA, or Probabilistic Risk Analysis,
are most interested in.
Has anyone heard of these terms, CDF and LERF?
Core Damage Frequency and Large Early Release Frequency.
All the fancy probability fault trees and everything
goes into calculating the probability
that the core gets damaged.
So that could be an accident in one right.
Or the probability of a radioactivity release.
And that is an accident.
So if no one's ever heard of this,
there's a city in Russia--
I don't know why it says Russland, maybe came
from a different language--
called Kyshtym, where they had the Mayak
nuclear and reprocessing plant.
And there was a tank full of radioactive waste
that was exploded.
It was a chemical explosion, but full of strontium,
all sorts of other radionuclides that
blew up with about 100 tons worth of TNT,
and ended up contaminating a rather large area
with this plume called the--
I think it's called the East Chelyabinsk Radioactive Trace--
or the--
what is it?
The south-- South-something Urals Radioactive Trace.
And that area is still contaminated today,
because the disaster was covered up, or rather wasn't--
nothing was said.
These towns here, they didn't--
weren't actually towns back in 1957 when this happened.
They were just given designations,
like Chelyabinsk-40 or Chelyabinsk-65,
because the largest nearby city was Chelyabinsk,