Shuting Fan Co-TERMINAL, MECHANICAL ENGINEERING Nuclear Fusion Hello everyone, Im shuting. Today I am going to talk about a very unique topic in the energy domain, which is nuclear fusion, I am currently a co-terminal student in mechaincial engineering And before I get started Shuting Fan Co-TERMINAL, MECHANICAL ENGINEERING

Motivation -Why I choose nuclear fusion as my topic today? Intern, EAST Tokamak Design Division, Institute of Plasma Physics, China Interested in learning the physics behind it and its potential economical and environmental value Designed and constructed CCD camera fixtures and specified camera for the outer inspection windows Inspected broken tiles and microwave tubes for the reaction chamber by operating the Articulate Inspection Arm (AIA) robotic arm * EAST Tokamak for Experimental Advanced Superconducting Tokamak I want to first talk to you about why I choose nuclear fusion as mu topic today. Two year ago, I interned in the east okamak design decision, institute of plasma physics in china Where I designed and constructed 12 ccd camera mount for the outer inspection window And beside that, I luckily got some experimentce in operating the articulate inspection arm. The articulate inspection arm is a 10 meter long arm with sever join and a camera at the tip, that can wrap around and look in side the chamber in both direction. This internship got me very interested in leaerned the knowledge behind nuclear fusion, and its potential economical and environmental value. So this is why I want to share with you all on what I learned and read so far.

Basic working Principal Nuclear fusion is a reaction in which two (or more) atomic nuclei come close enough to form one (or more) different atomic nuclei and subatomic particles. In practice, under certain condition, two isotopes of Hydrogen, deuterium H-2 and tritium H-3(Sources and resources), are fused into one Helium plus one extra neutron, generating huge amount of energy during the process. Blue represents proton Red represents neutron First of all, we will need to understand the basic working principal of nuclear fusion. Nuclear fusion is a reaction in which 2 or more atomic nuclei come close enough to form one or more difference atomic nuclei and subatomic particle. On the sun, the nuclear fusion is happened using the regular h1 hydrogen atom. On earth, in practice, we use deuterium and trituium are the reactant and fused into one under certain codition. Look at this picture, you see a deuterium with one proton and one neutron is fused with a triuterium which has one proton and two neutron and the result is one helium with two proton and two neutron plus one extra neutron. And this process generate huge amount energy

Energy Production - the potential of nuclear fusion When comparing the mass of the product (a helium atom and a neutron) to the mass of the reactant ( a deuterium plus a tritium), you will see that the mass is lost during the reaction. That’s the mass that converted into energy as the nuclei fused together following Einstein's famous equation 𝑬=𝒎 𝒄 𝟐 𝑐=3∗ 10 8 𝑚/𝑠 Now the next question would be how large amount of energy it is generated. So when you compare the mass of the product, which is a helium plus a neutron to the mass of the reactant which is a determum and a tritium. You will see that the mass is lost during this process. This mass is converted into energy which rigidly following the most famous Einstein’s equation E=mc square. We all know that c is the speed of light, which equal to 3 time 10 to the 8, and then you square it and get, 9 time 10 to the 16 So you see that even if you have a small amount of mass. You will still ended up with a large amount of energy released. To give you a example. 1gram of pure hydrogen contains this much of atoms, (I don’t know how to read this). Each of these 2 atoms will generate 17.59miliipon electron volts. This is a very small value. But consider the amount of atoms you have. The amount of energy it generated is huge. Of couse, this value varies a bit for deuterium and tritium, but it will be pretty similar 1g of pure hydrogen contains 600,000,000,000,000,000,000,000 atoms (value varies for H-2 and H-3 but similar) Each reaction generates17.59 million electron volts (MeV)

Working condition - Technological challenges To allow fusion reaction releasing energy in an controlled manner. Three requirements must be reached: Temperature Physicist estimates that the sample of deuterium and tritium needs to be heated to ~ 40 million kelvin. The temperature of the core of sun is ~15 million Kelvin. Time Deuterium and tritium must be held together long enough in a close distance to initiate the reaction. Researcher estimates that ~ 1 second is need. Containment At 40 million kelvin, everything would vaporized in gas. Thus, Researchers think about using magnetic fields to contain the plasma, as plasma has a charge. Magnetic fields in current nuclear fusion devices all have leaking problem. I just mentioned that, this reaction would only happened under a certain condition. So what condition does it has to follow in order to ignite the reaction? First is the temperature. The researcher estimates that in order for deuterium and tritium to reaction in a controlled manner. A teramperature of around 40 million deliven has to be reached. And let me reminds you that the temperature of the core of the sun is around 15million. Second is time, Physics estimate that in order for the reaction to happen, a deuterium and a tritium must be held very close together for around one 1 second. You can think of deuterium and tritium as two north poles on two magnet. And we haven’t be able to achieve it yet. Third is the containment. You can imagine that at a tmeprature of 40 million kelvin, everything will vaporiised into gas. And the only thing it last is plasma. Researcher are thinking about use the magnetic fiel to confine the plasma, as the plasma has charge. However the current magnetic field we build all have leaking problems, and one the plasma leave, the reaction colllaps.

Current status -Where are we right now? In 2013, Chinese scientists at EAST tokamak test reactor achieves a record confinement time of 30 seconds for plasma in the high-confinement mode (H-mode), thanks to improvements in heat dispersal from tokamak walls. This is an improvement of an order of magnitude with respect to state-of-the-art reactors In 2014, US Scientists at NIF successfully generate more energy from fusion reactions than the energy absorbed by the nuclear fuel (Break even point) The world's largest tokamak project, ITER, is scheduled to begin operation in 2020 So after all these knowleges, how we are doing right now. In the year 2013, in china, the east tokama managaege toachieve a confinement time of 30 second during the improvement of the ceramic wall, and previously , the highest record is 2 or 3 second. IN the year 2014, in us, the nif first be able to reach a break even point in the human history for neaclear fusion, that is the amount of envery that get put into the device is same as amount of energy that take out the the device In 2020, we are going to have the world largest tokamak project built by 8 major contries, and 35 total contries in france. And with a improving in all temperature, confinement ITER, Southern France France, China, India, Japan, Korea, Russia and USA EAST, Hefei, China NIF, Livemore, USA

Source of reactant Deuterium is a minor isotope of hydrogen, but it’s still relatively abundant. Tritium doesn’t occur naturally, but it can easily be produced by bombarding deuterium with a neutron. The source of the reaction is theoretically unlimited bombarding

Environmental & Public Safety The future that nuclear fusion offers is amazingly promising. It generates huge supplies of clean energy made from deuterium and tritium that are theoretically unlimited. It generates no nuclear waste or pollution There's no risk of nuclear accidents similar to those that have occurred with fission plants Fukushima: a nuclear war without a war Researchers estimate we're still several decades from seeing commercial fusion plant, and it always seems decades away. It’s a race of the technology against the time. So, before human being starting facing energy crisis, before climate change started affect regular life, can nuclear fusion really made it to success?

Reference " Nuclear Fusion : WNA - World Nuclear Association ". World- nuclear.org. N. p., 2017. Web. 2 Feb. 2017. "How Nuclear Fusion Works". Explain that Stuff. N. p., 2017. Web. 2 Feb. 2017. "Nuclear Fusion: The Hope For Our Energy Future ". Wiley, N. p., 2017. Web. 2 Feb. 2017.

Thank you!