Could Nuclear Weapons Save the Planet? | Sunniva Rose | TEDxBergen

could nuclear weapons save the planet I'm gonna give you five seconds to think about that before I continue on August 6th 1945 an American b-29 bomber dropped the world's first atomic bomb on Japanese city of Hiroshima the bomb with a code name little boy carried 64 kilograms of highly enriched uranium and when it exploded it wiped out 90% of the city and killed immediately 80,000 people three days later another atomic bomb was dropped on the city of Nagasaki killing 40,000 people 6 days after these attacks Japan announced the surrender in World War 2 the bombings of these two Japanese cities was a sad start of a nuclear arms race we're at the most something like 65,000 nuclear weapons existed worldwide 65,000 in the 1980s today there are only 16,000 nuclear weapons left in the world that is better than 65,000 but is still 16,000 too many the development of these atomic bombs was started a new era the arms race but also luckily the civil use of nuclear power a lot of the pro neuters many of my colleagues around the world would normally never ever talk about nuclear weapons and nuclear energy at the same time and I understand a reason because very often I've experienced that people only sort of possess one file in their brain which is labeled neuter and that nuclear file contains everything bad its weapons and it's radiation and its death and not very nice things and the fact is that when it comes to nuclear energy or a weapons there are some things that are exactly the same for a bomb and a reactor and there are definitely things that are very very different so I'm going to start with the similar and talk a little physics so the nuclear label energy comes from fishing what we see here is a heavy uranium nucleus uranium-235 and a neutral the neutral hits this uranium-235 nucleus and it becomes unstable and then officience it splits into two and it release huge amounts of energy the energy release here and fishing it's 50 million times bigger than the energy release in a typical chemical reaction what you would get if you burn something like four simple coal 50 million times more Perficient compared to one chemical reaction and this energy release that is the energy energy release that makes an atomic explosion so horrifying and why it as a weapon of mass destruction but it also the energy release that we can use in a very good way so even if there is fishing going on in a weapon and there is fishing going on in a reactor they are definitely not the same thing in a weapon more than 90% of the material in it is this uranium-235 in a reactor it is more like 5% also when you have this fishing and the energy release you also see that you get these extra nutrients coming out here you see you have three nutrients coming out and these nutrients they can hit other uranium nuclei and give us a chain reaction like this for example and then and here we see the difference on the right side here in a nuclear fuel you have a slow controlled chain reaction one Neutron in is one efficient and one Neutron gives another fishing and another fishing and another fishing on the weapons side you see one nutrient going in you have three nutrients out those three neutrons is three new new clay from each of them you have three more nutrients going out hitting three every time and you had this fast uncontrolled nuclear chain reaction releasing all of the energy at the same time so there are mainly two big differences on a nuclear weapon and a nuclear reactor one thing I already said is the 90 percent enrichment then ninety percent clear eight into thirty five in the neutral weapon whereas in a nuclear fuel we have only five percent and the rest of it is another type of uranium that doesn't fashion the other thing is how it is designed because a nuclear weapon is the sign to do that a nuclear reactor is designed to do that and one thing I always I have to stress it is that a nuclear reactor could never ever explode like a nuclear weapon it is not physically possible he can't but a nuclear weapon could quite easily be changed into nuclear fuel which is exactly what they did in a megatons to megawatts program the megatons to megawatts program was a US government industry partnership where weapons-grade uranium from old Russian nuclear warheads was recycled mixed with natural uranium which is that other type of uranium and turn into fuel that was bought for American part nuclear power plants as they called the largest and most successful nuclear non-proliferation program to date and I was thinking back just before I was going to give this talk I was thinking have any of you here in the audience heard about the megatons to megawatts program and I'm not talking about my boyfriend or the other speakers that I've already talked about this someone is nodding someone has write about it okay what I'm gonna tell you who haven't this program lasted from 1993 to 2013 so it was 20 years I think there are a lot of people here who are in the year and beginning under 20 so this is a program has been going on for most of your lives and in this program 500 tons a weapons-grade material highly enriched uranium was recycled and mixed with natural uranium and turned into fuel this is the same as 20,000 Russian nuclear warheads turned into fuel and 20,000 weapons for 20 years that's more than two weapons being destroyed every day for 20 years and if I'm gonna make a little I'm a little m hypothetically hypothetical thought here if we pretended that all of those twenty thousand nuclear weapons that they were like the Hiroshima bomb and let's say that those twenty thousand weapons would dropped over twenty thousand cities killing the same amount of people that is the same as 1.6 billion people of course we can't say that we saved 1.6 billion people because hopefully nuclear weapons will never be used again but I think it's an interesting number and this program has given the US for those 20 years 10 percent of all the electricity they have used for 20 years that's a lot and most of us have never heard about it so pure fissile uranium-235 makes a bomb if you have enough of it it's not just enough to have like 10 grams you have to have several kilograms and fissile uranium with natural uranium makes standard uranium fuel one issue with nuclear power however is that you will get this long-lived radioactive waste and that radioactive waste is actually made not from the fissile uranium would the uranium 238 so how could we solve that problem because we could do even better than the megatons to megawatts program if we mix this with thorium the forgotten element thorium is an element that was discovered by a swede in norway and named after the Norse god of thunder Thor thorium is an element that is not fissile in itself but if you mix it with something that is fissile something like weapons uranium for example you can make excellent fuel out of it and well that's the same thing that happens if you take this as I already told you about we're taking weapons you raining and uranium and mixing it with natural uranium so why would you use the thorium then well first of all you have four times more thorium in the world and you have uranium that's one reason but more importantly when you mix the weapons uranium with thorium well you're of course destroying the weapons that's nice but with thorium some of the story will be regenerated into fissile and fissile uranium and so you are sort of regenerating and making more fuel than you are burning that sounds in a way almost to need to be through true but it's actually s true and that means that you can also recycle the spent fuel and that means that you don't get the same problem with waste the waste problem is very very low so the megatons to megawatts project is great but mixing thorium with highly enriched uranium that is awesome so recycle recycle recycle recycle we've all heard about recycling but normally that's not what we talked about when we talk about nuclear so recycle we could recycle all the 16,000 nuclear weapons into climate neutral fuel and if you mix it with thorium we can also recycle this fuel and get rid of the waste problem so could nuclear weapons save the planet well not on its own but well one point is that if there are 16,000 nuclear weapons in the world they could at least maybe not destroy the planet totally they can make a lot of fuss so by destroying these weapons you are sort of saving the planet and doing that but even better you get this mission free clean energy so I like nuclear energy and I don't like nuclear weapons today in those 16,000 nuclear weapons is the same as 1,400 tons of highly enriched uranium so that's about three times the amount of what was converted into fuel in this megatons to megawatts program so if we just did it the same way that they did that would mean that we would get well six years of the total electricity use of the u.s. but that's sort of if we do it in the worst possible way because I've said that we could do this much better maybe we could get there ten times bit better maybe even hundred times better and then we're starting to talk so a nuclear weapon is ugly but by mixing the fissile material in it the uranium or thorium it can change into beautiful nuclear fuel and that is in my book one step towards saving the planet thank you

Channel: TEDx Talks

Views: 34,175

Rating: 4.6214833 out of 5

Keywords: TEDxTalks, English, Norway, Science (hard), Chemistry, Education, Nuclear weapons, Physics, Technology

Id: T0NFkZc__os

Length: 14min 43sec (883 seconds)

Published: Fri Oct 23 2015