Ian Hutchinson is a nuclear engineer and plasma physicist at MIT. He has made a number of important contributions in plasma physics including the magnetic confinement of plasmas seeking to enable fusion reactions, which is the energy source of the stars, to be used for practical energy production. Current nuclear reactors are based on fission as we discuss. Ian has also written on the philosophy of science and the relationship between science and religion.

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EPISODE LINKS:
Ian's Website: https://www-internal.psfc.mit.edu/~hutch/
Can a Scientist Believe in Miracles? (book): https://amzn.to/30aooVT
Monopolizing Knowledge (book): https://amzn.to/2Xb2a4q

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OUTLINE:
0:00 - Introduction
5:32 - Nuclear physics and plasma physics
8:00 - Fusion energy
35:22 - Nuclear weapons
42:06 - Existential risks
50:29 - Personal journey in religion
56:27 - What is God like?
1:01:34 - Scientism
1:04:21 - Atheism
1:06:39 - Not knowing
1:09:57 - Faith
1:13:46 - The value of loyalty and love
1:23:26 - Why is there suffering in the world
1:35:08 - AGI
1:40:27 - Consciousness
1:48:14 - Simulation
1:52:20 - Adam and Eve
1:54:57 - Meaning of life

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a conversation with Ian Hutchinson, a nuclear engineer and plasma physicist at MIT.

He has made a number of important contributions in plasma physics, including the magnetic confinement of plasmas, seeking to enable fusion reactions, which happens to be the energy source of the stars, to be used for practical energy production.

Current nuclear reactors, by the way, are based on fission, as we discuss.

Ian has also written on the philosophy of science and the relationship between science and religion, arguing in particular against scientism, which is a negative description of the overreach of the scientific method to questions not amenable to it.

On this latter topic, I recommend 2 of his books, his new 1, Can a Scientist Believe in Miracles, where he answers more than 200 questions on all aspects of God and science in his earlier book on scientism called Monopolizing Knowledge.

As you may have seen already, I work hard on having an open mind, always questioning my assumptions, and in general marvel at the immense mystery of everything around us and the limitations of at least my mind.

I'm not religious myself in that I don't go to the synagogue, a church, or mosque, but I see the beautiful bond in the community that religion at its best can create.

I also see, both in scientists and religious leaders, signs of arrogance, hypocrisy, greed, and a Will to Power.

We're human, whether Buddhist, Christian, Hindu, Jewish, Muslim, agnostic or atheist, this podcast is my humble attempt to explore a complicated human nature, what Stanislaw Lem in his book Solaris called Our Own Labyrinth of Dark Passages and Secret Chambers.

I ask that you try to keep an open mind as well and be patient with the limitations of mind.

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And now, here's my conversation with Ian Hutchinson.

Maybe it'd be nice to draw a distinction between nuclear physics and plasma physics.

Nuclear physics is about the physics of the nucleus and my department, Department of Nuclear Science and Engineering at MIT, is very concerned about all the interactions and reactions and consequences of things that go on in the nucleus, including nuclear energy, fission energy, which is the nuclear energy that we have already, and Fusion energy, which is the energy source of the sun and stars, which we don't quite know how to turn into practical energy for humankind at the moment.

That's what my research has mostly been aimed at.

But plasmas are essentially the fourth state of matter.

So if you think about solid, liquid, gas, plasma is the fourth of those states of matter.

And it's actually the state of matter which 1 reaches if 1 raises the temperature.

So cold things like ice are solid, liquids are hotter water, and if you heat water beyond 100 degrees Celsius, it becomes gas.

And plasma is a state of matter in which the electrons are unbound from the nuclei, so they become separated from the nuclei and can move separately.

So we have positively charged nuclei and we have negatively charged electrons.

The net is still electrically neutral, but a plasma conducts electricity, has all sorts of important properties that are associated with that separation, and that's what plasmas are all about.

And the reason why my department is interested in plasma physics very strongly is because most things, well, for 1 thing, most things in the universe are plasma.

The vast majority of matter in the universe is plasma, but most particularly, stars and the Sun are plasmas because they're very hot and it's only in very hot states that nuclear fusion reactions take place and we want to understand how to implement those kind of phenomena on Earth.

Maybe another distinction we wanna try to get at is the difference between fission and fusion.

So you mentioned fusion is the kind of reaction happening in the sun, so what's fission and what's fusion?

Well, fission is taking heavy elements like uranium and breaking them up, And it turns out that that process of breaking up heavy elements releases energy.

It means that there are many nuclear particles in the nucleus itself, neutrons and protons in the nucleus itself.

So that in the case of uranium, there are 92 protons in each nucleus and even more neutrons so that the total number of nucleons in the nucleus.

Nucleons is short for either a proton or a neutron.

The total number, you know, might be 235, that's U-235, or it might be 238, that's U-238.

Light elements, by contrast, have very few nucleons, protons or neutrons, in the nucleus.

There are actually slightly heavier forms of hydrogen isotopes.

Deuterium has a proton and a neutron, and tritium has a proton and 2 neutrons, so it has a total of 3 nucleons in the nucleus.

Well, taking light elements like isotopes of hydrogen and not breaking them up but actually fusing them together, reacting them together to produce heavier elements.

Typically helium, Okay, which is helium is a nucleus which has has 2 protons and 2 neutrons That also releases energy and that and that or reactions like that making heavier elements from lighter elements is what mostly powers the sun and stars.

Both fusion and fission release approximately a million times more energy per unit mass than chemical reactions.

So a chemical reaction means take hydrogen, take oxygen, react them together, let's say, and get water.

The energy released in a chemical reaction like that or the burning of coal or oil or whatever else is about a million times less per unit mass than what is released in nuclear reactions.

And actually it's very easy to understand why.

And that is that those 2 nuclei, if they're both, let's say, hydrogen nuclei, 1 is, let's say, deuterium and the other is, let's say, tritium, they're both electrically charged.

And they're positively charged, so like charges repel.

So basically, to get them close enough together to react, you have to overcome the electric repulsion of the 2 nuclei from 1 another.

And you have to get them extremely close to 1 another in order for the nuclear forces to overtake the electrical forces and actually form a new nucleus.

And so, 1 requires very high energies of impact in order for reactions to take place.

And those high energies of impact correspond to very high temperatures of random motion.

So that's why you can do stuff like that in the sun.

So we can build the sun, that's 1 way to do it.

But on Earth, how do you create a fusion reaction?

Well, nature's fusion reactors are indeed the stars and they are very hot in the center and they reach the point where they release more energy from those reactions than they lose by radiation and transport to the surface and so forth.

And that's what we have to achieve to give net energy.

If you have a bundle of sticks and you hold a match up to it and you see smoke coming from the sticks, but you take the match away and the sticks just fizzle out, the reason they fizzled out is that, yes, they were burning, there was smoke coming from them, but they were not ignited.

But if you are able to take the match away and they keep burning and they are generating enough heat to keep themselves hot and hence keep the reactions going, that's chemical ignition.

What we need to do, what the stars do in order to generate nuclear fusion energy, is they are ignited.

They are generating enough energy to keep themselves hot.

And that's what we've got to do on Earth if we're going to make fusion work on Earth.

But it's much harder to do on Earth than it is in a star.

Because we need temperatures of order tens of millions of degrees Celsius in order for the reactions to go fast enough to generate enough electricity to keep it, or enough energy to keep it going.

And so if you've got something that's tens of millions of degrees Celsius, and you want to keep it all together and keep the heat in long enough to have enough reactions taking place.

You can't just put it in a bottle, plastic or glass, it would be gone in milliseconds.

So you have to have some non-material mechanism of confining the plasma.

In the case of stars, that non-material force is gravity.

So gravity is what holds a star together, it's what holds the plasma in long enough for it to react and sustain itself by the fusion reactions.

I mean, I don't mean to say we don't fall.

But the mutual gravitational attraction of small objects is very weak compared with the electrical repulsion or any other force that you can think about on Earth.

And so we need a stronger force to keep the plasma together, to confine it.

And the predominant attempt at making fusion work on Earth is to use magnetic fields to confine the plasma.

And that's what I've worked on for much, essentially most of my career, is to understand how we can and how best we can confine these incredibly hot gases, plasmas, using magnetic fields with the ultimate objective of releasing fusion energy on Earth and generating electricity with it

So on top of the magnetic fields, do you also need the plastic water bottle walls or is it purely magnetic fields?

Well, actually, what we do need walls, those walls must be kept away from the plasma because otherwise they'd be melted.

Well, the plasma must be kept away from them, inside of them.

But the main purpose of the walls is not to keep the plasma in, it's to keep the atmosphere out.

So if we want to do it on Earth where there's air, we want the plasma to consist of hydrogen isotopes or other things, the things we're trying to react.

And By the way, the density of those plasmas, at least in magnetic confinement fusion, is very low.

It's maybe a million times less than the density of air in this room.

So in order for a fusion reactor like that to work, you have to keep all of the air out and just keep the plasma in.

So yes, there are other things, but those are things that are relatively easy.

I mean, making a vacuum these days is technologically quite straightforward.

What we don't quite know how to do is to make a confinement device that isolates the plasma well enough so that it's able to keep itself burning with its own reaction.

So maybe, can you talk about what a tokamak is?

The Russian acronym from which the word tokamak is built just means toroidal magnetic chamber.

A torus is a geometric shape which is like a donut with a hole down the middle, okay?

And so it's the meat of the donut, okay, that's the torus.

But the particular configuration that is very widespread and is the sort of best prospect, at least in the near term, for making fusion energy work, is 1 in which there's a very strong magnetic field the long way around the donut, around the torus.

So you've got to imagine that there's this donut shape with an embedded magnetic field just going round and round the long way.

The big advantage of that is that plasma particles, when they're in the presence of a magnetic field, feel strong forces from the magnetic field, and those forces make the particles gyrate around the direction of the magnetic field line.

So basically, the particles follow helical orbits, following like a spring that's directed along the magnetic field.

Well, if you make the magnetic field go inside this toroidal chamber and just simply go round and round the chamber, then because of this helical orbit, the particles can't move fast across the magnetic field, but they can move very quickly along the magnetic field.

And if you have a magnetic field that doesn't leave the chamber, it doesn't matter if they move along the magnetic field.

It doesn't mean they're going to exit the chamber.

But if you just had a straight magnetic field, for example, coming from Helmholtz coil or a bar magnet, then you'd have to have ends.

It would come to the ends of the chamber somewhere and the particles would hit the ends and they would lose their energy.

So that's why it's toroidal and that's why we have a strong magnetic field.

It's providing a confinement against motion in the direction that would lead the particles to leave the chamber.

It turns out that, and here we're getting a little bit technical, but it turns out that a toroidal field alone is not enough and so you need more fields to produce true confinement of plasma and we get those by passing a current as well through the plasma itself.

Well, what that does is makes the field lines themselves into much bigger helices.

And that's for reasons that are too complicated to explain, that clinches the confinement of the particles, at least in terms of their single particle orbit, so they don't leave the chamber.

And so when the particles are flying along this donut, the inside of the donut, where's the generation of the energy coming from?

Yeah, eventually, I mean in a fusion reactor, there will be deuterons and tritons, and they will be smashing in, they will be very hot.

They'll be 100 million degrees Celsius or something.

So they're moving thermally with very large thermal energies in random directions, and they will collide with 1 another and have fusion reactions.

When those fusion reactions take place, energy is released, large amounts of energy is released in the form of particles.

1 of the particles that's released is an alpha particle which is also charged and it's also confined.

And that alpha particle stays in the donut and heats the other particles that are in that donut.

So it transfers its energy to those and it keeps them hot.

There's some leaking of heat all the time, a little bit of radiation, some transport and so forth.

There's also a neutron released from that reaction.

The neutron carries out 4 5ths of the fusion energy and that will have to be captured in a blanket that surrounds the chamber in which we take the energy, drive some kind of electrical generator from thermal engine, gas turbine or something like that, and power the engine.

On getting this thing to be something that actually works, that generates energy.

Well, there have been experiments that have generated net nuclear energies or nuclear powers in the vicinity of, you know, a few tens of megawatts for a few seconds.

But we have studied how well Tokamaks can find plasmas.

And so we now understand in rather great detail the way they work.

And we're able to predict what is going to be required in order to build a tokamak that becomes self-sustaining, that becomes essentially ignited, or so close to ignited that it doesn't matter.

And at the moment, at least if you use the modest magnetic field values, still very strong, but limited magnetic field values, you have to build a very big device.

And So we are at the moment, worldwide fusion research is at the moment in the process of building a very big experiment that's located in the south of France.

It's called ITER, I-T-E-R, which means the way or just means the International Tokamak Experimental Reactor if you like.

And that experiment is designed to reach this burning plasma state and to generate about 500 megawatts of fusion power for hundreds of seconds at a time.

It won't put electricity on the grid or anything like that.

It's to figure out whether it works and what the remaining engineering challenges are.

It won't be engineered to run round the clock and so on and so forth, which ultimately 1 needs to do in order to make something that's practical for generating electricity.

But it will be the first demonstration on Earth of a controlled fusion reaction for a long time period.

CW – It's been an objective that has in many ways motivated my entire career and the career of many people like me in the field.

I have to admit though, that 1 of the problems with ETA is that it's an extremely big and expensive and long time to build experiment.

And so it won't even come into operation until about

even though it's been being built for 10 years and it was designed for 30 years before that.

And so that's actually 1 of the big disappointments of my career in a certain sense, which is that we won't get to a burning fusion reaction until well past the first operation of ITER, and whether I'm alive or not, I don't know, but I certainly will be well and truly retired by the time that happens.

And so when I realized maybe some years ago that that was gonna be the case, it was a discouragement to me, let's put it like that.

But if we can try to look, maybe in a ridiculous kind of way, look into 100 years from now, 200 years, 500 years from now, and we, you know, there's folks like Elon Musk trying to travel outside the solar system.

I mean, the amount of energy we need for some of the exciting things we wanna do in this world, if we look again, 100 years from now, seems to be a very large amount.

So do you think fusion energy will eventually, sometime into your retirement, will be basically behind most of the things we do.

Look, I absolutely think that fusion research is completely justified.

In fact, we should be spending more time and effort on it than we currently do.

But it isn't going to be a magic bullet that somehow solves all the problems of energy.

By the way, that's a generic statement you can make about any energy source in my view.

I think it's a grave mistake to think that science of any sort is suddenly going to find a magic bullet for meeting all the energy needs of society or any of the other needs of society, by the way.

But fusion is very worthwhile and we should be doing it.

And so my disappointment that I just expressed was in a certain sense a personal disappointment.

I do think that fusion energy is a terrific challenge.

It's very difficult to bring the energy source of the sun and stars down to Earth.

This does contrast, in a certain sense, with fission energy.

By contrast, fission energy, to build a fission reactor, proved to be amazingly easy.

We did it within a few years of discovering nuclear fission.

People had figured out how to build a reactor and did so during the Second World War.

Which is, by the way, fission is how the current nuclear power plants work.

Yeah, and so we have nuclear energy today because fission reactors are relatively easy to build.

What's hard is getting the materials, okay?

And that's just as well because if everyone could get those materials, there would be weapons proliferation and so forth.

But it wasn't all that long after even the discovery of nuclear fission that fission reactors were built and fission reactors, of course, operated before we had weapons.

So, I think nuclear power is obviously important to meet the energy challenges of our age.

It is completely, intrinsically, completely CO2 emissions free.

And in fact, the wastes that come from nuclear power, whether it's fission or fusion for that matter, are so moderate in quantity that we shouldn't really be worried about them.

I mean, yes, fission products are highly radioactive and we need to keep them away from people, but there's so little of them it's that keeping them away from people is not particularly difficult.

And so while people complain a lot about the drawbacks of fission energy, I think most of those complaints are ill-informed.

We can talk about the challenges and the disasters, if you like, of fission reactors.

But I think fission, in the near term, offers a terrific opportunity for environmentally friendly energy, which in the world as a whole is rapidly being taken advantage of.

You know, China and India and places like that are rapidly building fission plants.

We're not rapidly building fission plants in the US, although we are actually building 2 at the moment, 2 new ones, but we do still get 20% of our electricity from fission energy and we could get a lot more.

Now, again, the concern is there's a very popular HBO show and just came out on Chernobyl.

There's the 3 Mile Island, there's Fukushima, that's the most recent disaster.

So there's a kind of a concern of, yeah, I mean of nuclear disasters.

Is that, what would you make of that kind of concern, especially if we look into the future of fission energy-based reactors?

Well, First of all, let me say 1 or 2 words about the contrast between fission and fusion, and then we'll come on to the question of the disasters and so forth.

Fission does have some drawbacks, and they're largely to do with 4 main areas.

1 is, do we have enough uranium or other fissile fuels to supply our energy needs for a long time?

The answer to that is we know we have enough uranium to support fission energy worldwide for thousands of years, but maybe not for millions of years.

Secondly, there are issues to do with wastes.

Fish and wastes are highly radioactive, and some of them are volatile.

And so for example, in Fukushima, the problem was that some fraction of the fission waste were volatilized and went out as a cloud and polluted areas with cesium-137, strontium-90, and things like that.

There's a problem of safety Beyond that, and that is that in fission, it's hard to turn the reactor off.

When you stop the nuclear reactions, there is still a lot of heat being liberated from the fission products.

And that is actually what the problem was at Fukushima.

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Ian Hutchinson: Nuclear Fusion, Plasma Physics, and Religion | Lex Fridman Podcast #112