Nuclear Energy, The Mini-Series: Episode 1 - What is Radiation?

Fossil fuels kill about 8 million people every single year, which is more than the populations of Aotearoa and most of the remaining Pacific Islands put together.

Nuclear power, though - it’s the one that evokes all of that terror and fear, and, well, fair enough because radiation sickness is terrifying. But I am fascinated by nuclear energy ever since I found out that Chernobyl happened on my birthday, albeit the year before I was born, but still - fascinating.

The big fact is that nuclear is a far safer way to create energy than fossil fuels.

So it begs the question: if nuclear energy’s fatality rate is orders of magnitude lower than coal’s, why are we still burning coal like it's 1890?

To get into this, I’m doing a 4-part series on nuclear power, and to start with, I’ll be discussing what it actually is.

Transcript

Kia ora, kaitiaki, and welcome to Now That's What I Call Green. I'm your host, Brianne West—an environmentalist and entrepreneur trying to get you as excited about our planet as I am. I'm all about creating a scientific approach to making the world a better place, without the judgement, and making it fun.

And of course, we will be chatting about some of the most amazing creatures we share our planet with. So if you are looking to navigate through everything green—or not so green—you have come to the right place.

Fossil fuels kill about 8 million people every single year, which is more than the populations of Aotearoa and most of the remaining Pacific Islands put together. And they will continue to claim many, many more, of course, as the planet continues to boil due to climate change, which is due to fossil fuels.

Nuclear power, though—the one that evokes all of that terror and fear and, well, you know, fair enough because radiation sickness is terrifying—that has, so far, in its entire 70-plus year history, killed fewer than 200 people. Granted, that's a bit more complicated, but we'll get into that later.

But if you bring this up on social media—man, do people get mad.

So kia ora, welcome back. I'm Brianne West and I am fascinated by nuclear energy. Ever since I found out that Chernobyl happened on my birthday—albeit the year before I was born—it's still fascinating.

Now, some of you are probably a little bit surprised by that previous “8 million people killed every year by fossil fuels” number. Because the one that you think will be the highest—nuclear—isn't. In fact, it's one of the lowest. It’s one of the safest ways to create energy that we have.

So it begs the question: if nuclear’s fatality rate is orders of magnitude lower than coal’s, why are we still burning coal like it’s 1890?

This episode was largely inspired by the news out of China that they have just done a world first. Now we’re going to be talking about that a bit later. But they’ve created a new type of reactor that has even fewer of the downsides that people worry about with uranium reactors.

But I also wanted to address this because a lot of people are really surprised to hear that I am pro-nuclear energy—because obviously, I’m an environmentalist and therefore you can’t be both. They’re mutually exclusive terms. Or so Greenpeace would have you believe.

And actually, it nearly lost me a job with Greenpeace.

Years ago—I think I was 18, just started at university—and they were advertising for those people on the street. Yeah, one of those annoying people who would accost you as you walked into malls. I do apologise.

I walked into the interview—which was half a day long, by the way, and involved role-playing, which was hell on Earth. But I walked in and one of the first questions was: “What do you know about Greenpeace?”

And I don’t remember what I said, but I did talk about how I was super pro-nuclear energy. And the interviewer interjected and said, “Do you know what Greenpeace was founded on?”

Because, of course, one of Greenpeace’s founding principles—and its origin story, if you like—is nuclear power and how it would kill us all.

A great lesson in doing prep for your job interviews.

This is a big chat, so I’m breaking it down into four episodes.

One is gonna talk about what the hell radiation is. It gets a wee bit technical, and if you don’t really care, I guess it’s not that important—you can skip this episode.

Number two: we’re going to talk about the discovery and history of radiation. Fascinating.

Part three talks a little bit about where we are, what countries are doing, how much energy is actually produced by nuclear, how much we could produce, do we need it—and answering that question that really we’re all here for, which is: do we need it?

And then there’s a startup right here in Aotearoa that is creating a fusion reactor. I mean, fricking awesome.

But first, let’s start with Radiation 101. And I know it sounds boring, but honestly, I find this fascinating. So fascinating that even though I’m doing my Master’s in microbiology, for some reason, I’m doing some papers in radiation because it’s just that interesting. I’d make a great supervillain—interested in viruses and radiation.

Right. Everything around us is atoms. You may have heard the saying: “All that exists is atoms and empty space”—and actually, empty space is the vast majority of it.

Every single one of those atoms around us was forged in space. Like I said: you are quite literally made of stars. And I mean, if that doesn’t interest you in particles, I don’t know what will.

The lightest, which is hydrogen—and most of the universe is helium—they were minted in the first three minutes of the Big Bang.

Anything heavier was created later, inside stars. So:

Carbon in the cores of red giants, for example

Oxygen in massive stars on the brink of collapse

But the real heavyweights—the ones that have got the most protons and neutrons in the nucleus, which we’re going to talk about in a minute—like gold, iodine, or uranium—they need much bigger forces, such as what you find inside supernovae or neutron star collisions.

Those cosmic events quite literally spray those elements around the galaxy, where they’re clumped into new solar systems, and eventually make their way into everything—including your cells.

So yeah, that—maybe you think—might be a bit weird. Kind of technically an alien, almost. Explains so much.

But what is an atom?

If we’re going to carry on using the idea of space, an atom is like a mini solar system.

So you’ve got the compact nucleus—which is the sun, for example—and that’s made of protons and neutrons.

Protons are positively charged particles and neutrons are neutral—so they have no charge.

And that nucleus is orbited by electrons, which are the negatively charged particles-slash-wave (that’s a bit complicated, we won’t go into it) that you’ve probably heard of because of electricity.

I hope I’m making this simple enough but not patronising. Any feedback on how I’m explaining a relatively complicated topic would be most appreciated.

I said before, “All that exists is atoms in empty space.” Well, atoms are actually mostly empty space, because the nucleus is minuscule beyond belief. It’s about one ten-thousandth the width of the entire atom itself.

The electrons, like an electron cloud, are orbiting around the outside, and that big gap is just empty space.

In a normal atom, the positive charge of the protons in the nucleus is counteracted by the negative charge of the electrons floating around it. It’s electrically neutral.

If you remove or add an electron, that atom then becomes reactive—and that is the basis of chemical reactivity. Because the atom wants to be neutral, so it will snatch or drop an electron from a neighbouring atom to get back to that neutral level.

But you can also change the proton count—but that literally changes the element. Because that’s how the element is identified, if you like—the number of protons.

If you add a proton to a nitrogen atom, which has seven protons, you get an oxygen atom.
If you take away a proton from a sodium atom, you make neon.

But chemistry can’t really do that in nature. That’s the kind of thing that nuclear reactions do.

So that’s radioactive decay, particle accelerator collisions—like in the Large Hadron Collider that you may have heard of—or smash-ups inside stars. That needs a lot of force.

Now, if you keep the proton number but you change the number of neutrons, you get an isotope.

So it’s the same element, new mass. No change in charge.

And this is where you will see numbers after elements. You may have seen something like carbon-14, for example.

Well, most carbon is carbon-12, so it means it has 12 protons, 12 neutrons, 12 electrons. That is a balanced atom.

But some carbon that exists in nature is carbon-14, so that means it has two extra neutrons.

So carbon-14 has two extra neutrons, and that leaves the nucleus lopsided.

So after about 5,730 years—that’s called a half-life, so the amount of time that half of a sample has decayed—one of those neutrons will change into a proton.

I am not going to go into that process—that’s complicated and we don’t need it for this episode.

But again, we’re talking about balance. So the atom will fire out a high-speed electron to keep the balance. That is something called a beta particle—and a neutrino, which takes away some of that excess energy.

So the charge is now balanced again. The nucleus has gained one positively charged proton, so it has changed into a different atom. And the electron that’s shot away, and a tiny flash of gamma light—that is the energy that makes the clicks you hear on a Geiger counter.

Because that is radioactivity.

And that’s actually what carbon dating is, actually—that particular example.

So that was a little bit technical, and I hope you have stayed with me, because wee bit more technicalness coming up. It’s worth it—hang in. You’ll be able to tell your friends at work how fascinating protons are. I don’t know.

Ultimately, radiation is: if the neutron-to-proton ratio in an atom isn’t balanced, it calms itself by emitting energy or a particle in some way, shape, or form.

Now, broadly speaking, there are two types of radiation: ionising and non-ionising.

As I mentioned, an ion is an atom that has a different number of electrons to protons, so it’s either positively or negatively charged.

Radiation that is energetic enough—so it has enough oomph—to knock electrons off other neighbouring atoms is called ionising radiation, because it can create ions from ordinary atoms.

Now that is important, because ionising radiation can knock electrons out of DNA molecules—and that is what ultimately can lead to cancer. And of course, all of the other horrific symptoms of radiation sickness.

But there’s also loads of different types of lower energy radiation.

So visible light would be a great example, but there’s also radio waves, there’s microwaves. They can heat up or jiggle molecules, if you like—but they cannot break chemical bonds because they simply don’t have the energy.

Therefore, it’s non-ionising, and you don’t have to worry about your cellphone anymore.

So there are four main types of ionising radiation.

The biggest is an alpha particle. It’s two protons and two neutrons—which is actually the nucleus of a helium atom (so it doesn’t have the electrons).

It’s very ionising. It has a lot of energy—but it’s also very slow.

So they are easily stopped by the outer layer of dead skin, or a piece of paper, or clothing. So they can’t penetrate from the outside.

However, they are extremely dangerous if you ingest an alpha particle emitter through inhalation or swallowing.

Then you have beta particles—or it might be “bay-ta,” I don’t know what Kiwis say. I’m going with beta.

These are those high-speed electrons that are ejected when a neutron changes to a proton. They penetrate through a few millimetres of tissue—but thin metal or plastic will block them.

Then you have the biggies that you may have heard about, which are gamma rays and X-rays.

They are high-energy light. X-rays are produced outside the nucleus; gamma rays come from the inside. Same physics, different origin.

Interestingly enough, they have no mass—but they are very deeply penetrating because they are high energy and they do the most damage.

Those are the things that you need dense shielding from—like lead and concrete.

Finally, you have neutrons—and they are the most important for today’s conversation.

Being neutrons, they are neutrally charged. But when they fly out of a reactor core, they are moving at thousands of kilometres a second—which is somewhat hard to imagine.

And the danger is in the insane kinetic energy that that brings with it.

They are easily absorbed or moderated by hydrogen-rich materials like water or deuterium—which is just an isotope of hydrogen—or, interestingly enough, plastic.

But you don’t really have to worry, because unless you’re hanging out near or inside a nuclear reactor, or you take a lot of very high-altitude flights (so much higher than your commercial flight), you’re probably never gonna come across them.

Each isotope has its own way of getting rid of its energy, based on its atomic structure—and that is why we see these different types of radiation.

If you’ve got very heavy atoms, such as radium-226, they’re too fat to split neatly. So they shave off compact alpha particles—which are the two neutrons and the two protons—and there’s a dash of gamma rays on the side.

Then you look at uranium-235—which is, of course, what we typically use in nuclear power plants (although maybe not for much longer—we’ll talk about that).

That decays very slowly on its own—until a slow neutron gives it a nudge, and then it flies apart in what we call fission.

That releases epic amounts of energy, more neutrons, and plenty of gamma rays—and that is exactly what you want in a controlled chain reaction like you find in an operating nuclear reactor. Or a well-operating nuclear reactor.

That is, of course, why most people think of uranium when they think of radiation.

Now, radiation can’t be seen, it can’t be smelt, it can’t be felt—and unfortunately, people have found that out the hard way.

Of course, because the people who discovered and worked with it in those early days learned how dangerous it was in the most horrendous ways.

They developed burns, anaemia, radiation sickness, of course, and obviously cancers.

And as we learned more, those fears were then amplified by the likes of Chernobyl and then Fukushima.

And they have hardwired that link between radiation and horrendous illness in most of our minds.

And now people are nervous about radiation to the point of being—well—irrational.

It’s not irrational to fear radiation.
It is irrational to fear nuclear energy.

How much of this do you actually need to cause damage, though?

The unit currently used to measure radiation is called a sievert, and that is kind of a funny measurement because it reflects the impact on a kilogram of biological tissue—not necessarily the amount of energy, but the impact. Because that’s really the most relevant to us.

To give you some examples:

If you have a chest X-ray, you will get about 0.1 millisieverts.

Your average background dose in Aotearoa would be about 2 millisieverts.

The regulatory limit for a lot of countries around the world, for people who work in nuclear power plants, is 20 millisieverts.

To the fun stuff:

1,000 millisieverts in one short burst will almost certainly lead to radiation sickness.

And 4 sieverts (not millisieverts) will kill 50% of people without treatment.

If you watched that absolutely bloody brilliant series Chernobyl—and if you haven’t, I really recommend it—you may have heard them refer to ronkin. That’s now outdated and not really useful, so I won’t be discussing it today.

Right. You can now take a deep breath, because we’re over the technical stuff—and well done for sticking with me.

I hope it was interesting and I hope it was clear. But really—send me some feedback if that wasn’t clear, because I am not a teacher and I’d love to know if there is a better way to help you understand these things.

So that was part one.

It was a lot, so you can all go and have a break now. Come back for part two when we’re going to talk about the history.

Mā te wā.

And there you go. I hope you learned something and realised that being green isn’t about everything in your pantry matching with those silly glass jars or living in a commune.

If that’s your jam—fabulous.

But sustainability, at its heart, is just using what you need.

If you enjoyed this episode, please don’t keep it to yourself—and feel free to drop me a rating and hit the subscribe button.

Kia ora, and I’ll see you next week.

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