Nearly everyone in the world is part of some community, whether large or small. And all of these communities have similar needs. They need light, they need heat they need air-conditioning. People can't function very well when it's too hot or too cold. They need food to be grown or provided, distributed and stored safely. They need waste products to be collected, removed and processed. People in the community need to be able to get from one place to another as quickly as possible. And a supply of energy is the basis for all of these activities. Energy in the form of electricity provides light and air-conditioning. Energy in the form of heat keeps us warm. And energy in chemical form provides fertilizer; it drives farm machinery and transportation energy.
Skoro svaka osoba na svetu je član neke zajednice, bila ona velika ili mala. Sve te zajednice imaju slične potrebe. Treba im svetlost, treba im toplota i treba im klimatizacija. Ljudi ne mogu da funkcionišu dobro ako im je prevruće ili prehladno. Treba da im se uzgaja ili obezbedi hrana, raspodeli i čuva na sigurnom. Potrebno im je da se otpadni proizvodi sakupe, uklone i obrade. Ljudima u zajednici je potrebno da mogu da odu sa jednog mesta na drugo što je brže moguće. Snabdevanje energijom je osnova za sve ove aktivnosti. Energija u obliku struje obezbeđuje svetlost i klimatizaciju. Energija u obliku toplote nas greje. A energija u hemijskom obliku nam obezbeđuje đubriva; ona pokreće poljoprivredne mašine i energiju za prevozna sredstva.
Now, I spent 10 years working at NASA. In the beginning of my time there in 2000, I was very interested in communities. But this is the kind of community I was thinking of -- a lunar community It had all of the same needs as a community on Earth would have, but it had some very unique constraints. And we had to think about how we would provide energy for this very unique community. There’s no coal on the Moon. There's no petroleum. There’s no natural gas. There's no atmosphere. There’s no wind, either. And solar power had a real problem: the Moon orbits the Earth once a month. For two weeks, the sun goes down, and your solar panels don't make any energy. If you want to try to store enough energy in batteries for two weeks, it just simply isn't practical. So nuclear energy was really the only choice.
Proveo sam 10 godina radeći u Nasi. Na samom početku, 2000. godine, bio sam veoma zainteresovan za zajednice. Ali ovo je vrsta zajednice na koju sam mislio - zajednica na Mesecu. Imala bi iste potrebe kao zajednica na Zemlji, ali i neka jedinstvena ograničenja. Morali smo da razmišljamo o tome kako bismo obezbedili energiju za ovu jedinstvenu zajednicu. Ne postoji ugalj na Mesecu. Ne postoji nafta. Ne postoji prirodni gas. Ne postoji atmosfera. Ne postoji ni vetar. Solarna energija bi imala pravi problem: Mesec se okrene oko Zemlje jednom mesečno. Tokom dve nedelje nema sunca, pa solarni paneli ne bi pravili nikakvu energiju. Ako pokušate da sačuvate energiju u baterijama tokom dve nedelje, to prosto ne bi bilo praktično. Nuklearna energija je bila zaista jedini izbor.
Now, back in 2000, I didn't really know too much about nuclear power, so I started trying to learn. Almost all of the nuclear power we use on Earth today uses water as a basic coolant. This has some advantages, but it has a lot of disadvantages. If you want to generate electricity, you have to get the water a lot hotter than you normally can. At normal pressures, water will boil at 100 degrees Celsius. This isn't nearly hot enough to generate electricity effectively. So water-cooled reactors have to run at much higher pressures than atmospheric pressure. Some water-cooled reactors run at over 70 atmospheres of pressure, and others have to run at as much as 150 atmospheres of pressure. There's no getting around this; it's simply what you have to do if you want to generate electricity using a water-cooled reactor. This means you have to build a water-cooled reactor as a pressure vessel, with steel walls over 20 centimeters thick. If that sounds heavy, that's because it is.
U 2000. godini nisam stvarno znao mnogo o nuklearnoj energiji, pa sam počeo da pokušavam da naučim. Skoro sva nuklearna snaga koju koristimo danas upotrebljava vodu kao osnovni rashlađivač. Ovo ima neke prednosti, ali ima i puno mana. Ako želite da proizvedete struju, morate da zagrejete vodu mnogo više nego što to obično možete. Pri normalnom pritisku, voda će prokuvati na 100 stepeni Celzijusa. To nije ni približno dovoljno vruće da bi se efektivno proizvela struja. Reaktori hlađeni vodom moraju da rade pri mnogo većem pritisku nego što je atmosferski pritisak. Neki reaktori hlađeni vodom rade pod pritiskom većem od 70 atmosfera, a drugi moraju da rade pri pritisku većem od 150 atmosfera. To ne može da se izbegne; to je ono što morate da uradite ako želite da proizvedete struju koristeći reaktor hlađen vodom. To znači da morate da izgradite reaktor hlađen vodom kao sud pod pritiskom, sa čeličnim zidovima debelim više od 20 centimetara. Ako to zvuči teško, to je zato što jeste.
Things get a lot worse if you have an accident where you lose pressure inside the reactor. If you have liquid water at 300 degrees Celsius and suddenly you depressurize it, it doesn't stay liquid for very long; it flashes into steam. So water-cooled reactors are built inside of big, thick concrete buildings called containment buildings, which are meant to hold all of the steam that would come out of the reactor if you had an accident where you lost pressure. Steam takes up about 1,000 times more volume than liquid water, so the containment building ends up being very large, relative to the size of the reactor.
Stvari postanu još gore ako imate nesreću da izgubite pritisak unutar reaktora. Ako imate tečnu vodu na 300 stepeni Celzijusa i odjednom je oslobodite pritiska, ne ostaje u tečnom obliku zadugo; transformiše se u paru. Reaktori koji se hlade vodom su izgrađeni unutar velikih debelih betonskih zgrada koje se zovu zaštitne zgrade, koje služe da zadrže svu paru koja bi izašla iz reaktora ukoliko biste imali nesreću da izgubite pritisak. Para zauzima oko 1 000 puta više zapremine nego voda u tečnom stanju, tako da je zaštitna zgrada veoma velika, u odnosu na veličinu reaktora.
Another bad thing happens if you lose pressure and your water flashes to steam. If you don't get emergency coolant to the fuel in the reactor, it can overheat and melt. The reactors we have today use uranium oxide as a fuel. It's a ceramic material similar in performance to the ceramics we use to make coffee cups or cookware or the bricks we use to line fireplaces. They're chemically stable, but they're not very good at transferring heat. If you lose pressure, you lose your water, and soon your fuel will melt down and release the radioactive fission products within it.
Još jedna loša stvar se dešava ako izgubite pritisak i ako se voda pretvori u paru. Ako ne ubacite rashlađivač u gorivo u reaktoru može da se pregreje i istopi. Reaktori koje imamo danas koriste uranijum-oksid kao gorivo. To je keramički materijal sličnih performansi kao keramika koju koristimo za šolje za kafu ili kuhinjsko posuđe, ili cigle koje koristimo za ograđivanje kamina. On je hemijski stabilan, ali nije baš dobar prenosilac toplote. Ako izgubite pritisak, izgubićete vodu, a ubrzo će vam se i gorivo istopiti i ispustiti produkte radioaktivne fisije.
Making solid nuclear fuel is a complicated and expensive process. And we extract less than one percent of the energy for the nuclear fuel before it can no longer remain in the reactor. Water-cooled reactors have another additional challenge: they need to be near large bodies of water, where the steam they generate can be cooled and condensed. Otherwise, they can't generate electrical power. Now, there's no lakes or rivers on the Moon, so if all of this makes it sound like water-cooled reactors aren't such a good fit for a lunar community, I would tend to agree with you.
Stvaranje izdržljivog nuklearnog goriva je komplikovan i skup proces. Izvlačimo manje od jednog procenta energije za nuklearno gorivo pre nego što više ne može da ostane u reaktoru. Reaktori koji se hlade vodom imaju još jednu spornu stvar: moraju da budu blizu nekog velikog izvora vode, gde para koju stvaraju može da se rashladi i kondenzuje. Drugačije ne mogu da proizvedu električnu energiju. Ne postoje ni jezera ni reke na Mesecu, pa ako vam se zbog svega ovoga čini da reaktori hlađeni vodom nisu baš podobni za zajednicu na Mesecu, ja bih se složio sa vama.
(Laughter)
(Smeh)
I had the good fortune to learn about a different form of nuclear power that doesn't have all these problems, for a very simple reason: it's not based on water-cooling, and it doesn't use solid fuel. Surprisingly, it's based on salt.
Imao sam sreću da naučim o različitim oblicima nuklearne energije koji nemaju sve ove probleme, zbog veoma prostog razloga: nisu zasnovani na hlađenju vodom i ne koriste čvrsta goriva. Iznenađujuće, zasnovani su na soli.
One day, I was at a friend's office at work, and I noticed this book on the shelf, "Fluid Fuel Reactors." I was interested and asked him if I could borrow it. Inside that book, I learned about research in the United States back in the 1950s, into a kind of reactor that wasn't based on solid fuel or on water-cooling. It didn't have the problems of the water-cooled reactor, and the reason why was pretty neat. It used a mixture of fluoride salts as a nuclear fuel, specifically, the fluorides of lithium, beryllium, uranium and thorium. Fluoride salts are remarkably chemically stable. They do not react with air and water. You have to heat them up to about 400 degrees Celsius to get them to melt. But that's actually perfect for trying to generate power in a nuclear reactor.
Jednog dana bio sam u kancelariji svog prijatelja, i zapazio sam knjigu na polici „Reaktori za tečna goriva“. Zainteresovao sam se i pitao sam ga da je pozajmim. Uz pomoć ove knjige sam saznao za američko istraživanje iz 1950-ih godina o vrsti reaktora koji nije zasnovan na čvrstim gorivima ili na hlađenju vodom. Nije imao probleme koje je imao reaktor koji se hladi uz pomoć vode, a razlog je divan. Koristi mešavinu fluoridnih soli kao nuklearno gorivo, naročito fluoride litijuma, berilijuma, uranijuma i torijuma. Fluoridne soli su hemijski stabilne. Ne ulaze u reakciju sa vazduhom i vodom. Morate da ih zagrejete do nekih 400 stepeni Celzijusa da biste ih istopili. To je zapravo idealno za pokušaj generisanja energije u nuklearnom reaktoru.
Here's the real magic: they don't have to operate at high pressure. And that makes the biggest difference of all. This means they don't have to be in heavy, thick steel pressure vessels, they don't have to use water for coolant and there's nothing in the reactor that's going to make a big change in density, like water. So the containment building around the reactor can be much smaller and close-fitting. Unlike the solid fuels that can melt down if you stop cooling them, these liquid fluoride fuels are already melted, at a much, much lower temperature. In normal operation, you have a little plug here at the bottom of the reactor vessel. This plug is made out of a piece of frozen salt that you've kept frozen by blowing cool gas over the outside of the pipe. If there's an emergency and you lose all the power to your nuclear power plant, the little blower stops blowing, the frozen plug of salt melts, and the liquid fluoride fuel inside the reactor drains out of the vessel, through the line and into another vessel called a drain tank. Inside the drain tank, it's all configured to maximize the transfer of heat, so as to keep the salt passively cooled as its heat load drops over time. In water-cooled reactors, you generally have to provide power to the plant to keep the water circulating and to prevent a meltdown, as we saw in Japan. But in this reactor, if you lose the power to the reactor, it shuts itself down all by itself, without human intervention, and puts itself in a safe and controlled configuration.
Evo je prava magija: ne moraju da funkcionišu pod velikim pritiskom. A to pravi najveću razliku. To znači da ne moraju da budu u debelim čeličnim sudovima pod pritiskom, ne moraju da koriste vodu kao rashlađivač, i ne postoji ništa u reaktoru što će napraviti veliku promenu u gustini kao što bi voda. Tako da zaštitna posuda oko reaktora može biti znatno manja i po meri. Za razliku od čvrstih goriva koja se tope ako ih ne rashlađujete, ova tečna fluoridna goriva su već istopljena na mnogo nižoj temperaturi. Pri normalnom funkcionisanju imate mali čep ovde na dnu reaktorskog suda. Ovaj čep je napravljen od komada zaleđene soli koji držite zaleđenim izduvavanjem hladnog gasa sa spoljašnje strane cevi. Ako postoji opasnost i izgubite svu energiju u nuklearnoj elektrani, kompresor prestaje sa izduvavanjem, zaleđeni čep soli se topi, pa tečno fluoridno gorivo unutar reaktora curi van reaktorskog suda kroz vod pa u drugi sud koji se zove rezervoar za odvod. U rezervoaru za odvod sve je konfigurisano tako da se prenese što više toplote, da bismo održali so ohlađenom dok njena toplota opada s vremenom. Kod reaktora hlađenih vodom obično morate da obezbedite struju elektrani kako biste održali cirkulaciju vode i sprečili topljenje, kao što smo videli u Japanu. Kod ovog reaktora, ako izgubite struju, on se gasi sam od sebe bez intervencije ljudi, i adaptira se u bezbednu i kontrolisanu konfiguraciju.
Now, this was sounding pretty good to me, and I was excited about the potential of using a liquid fluoride reactor to power a lunar community. But then I learned about thorium, and the story got even better. Thorium is a naturally occurring nuclear fuel that is four times more common in the Earth's crust than uranium. It can be used in liquid fluoride thorium reactors to produce electrical energy, heat and other valuable products. It's so energy-dense that you could hold a lifetime supply of thorium energy in the palm of your hand. Thorium is also common on the Moon and easy to find. Here's an actual map of where the lunar thorium is located. Thorium has an electromagnetic signature that makes it easy to find, even from a spacecraft.
Ovo mi je zvučalo prilično dobro, i bio sam uzbuđen zbog potencijalnog korišćenja reaktora za tečne fluoride da pokrenemo zajednicu na Mesecu. Ali onda sam saznao za torijum, pa je priča postala još bolja. Torijum je nuklearno gorivo koje se javlja u prirodi, i koje je četiri puta češće u Zemljinoj kori od uranijuma. Može se koristiti u reaktorima za tečne fluoride kako bi se proizvela električna energija, toplota i drugi važni proizvodi. Tolika je gustoća energije da biste mogli da držite večnu zalihu energije torijuma na svom dlanu. Torijum je takođe čest na Mesecu i lako ga je pronaći. Na ovoj mapi je prikazano gde je lociran torijum na Mesecu. Torijum ostavlja elektromagnetni trag koji je lako pronaći čak i iz svemirskog broda.
With the energy generated from a liquid fluoride thorium reactor, we could recycle all of the air, water and waste products within the lunar community. In fact, doing so would be an absolute requirement for success. We could grow the crops needed to feed the members of the community even during the two-week lunar night, using light and power from the reactor. It seemed like the liquid fluoride thorium reactor, or LFTR, could be the power source that could make a self-sustainable lunar colony a reality.
Sa energijom koju proizvodi reaktor za tečni fluoridni torijum mogli bismo da recikliramo sav vazduh, vodu i otpadne proizvode u okviru zajednice za Mesecu. U stvari, to bi bio uslov za uspeh. Mogli bismo da gajimo useve kako bi se nahranili članovi zajednice čak i tokom dvonedeljne noći na Mesecu koristeći svetlost i struju iz reaktora. Izgledalo je kao da bi reaktor za tečni fluoridni torijum, ili RTFT, mogao biti izvor energije koji bi pretvorio samoodrživu koloniju na Mesecu u stvarnost.
But I had a simple question: If it was such a great thing for a community on the Moon, why not a community on the Earth, a community of the future, self-sustaining and energy-independent? The same energy generation and recycling techniques that could have a powerful impact on surviving on the Moon could also have a powerful impact on surviving on the Earth. Right now, we're burning fossil fuels because they're easy to find and because we can. Unfortunately, they're making some parts of our planet look like the Moon. Using fossil fuels entangles us in conflict in unstable regions of the world and costs money and lives.
Imao sam jednostavno pitanje: ako bi to bila tako dobra stvar za zajednicu na Mesecu, zašto ne bi i za zajednicu na Zemlji, zajednicu budućnosti, samoodrživu i energetski nezavisnu? Ista proizvodnja energije i tehnike reciklaže koje bi mogle imati snažan uticaj na preživljavanje na Mesecu mogle bi imati snažan uticaj i na preživljavanje na Zemlji. Trenutno sagorevamo fosilna goriva jer ih je lako pronaći i zato što možemo. Nažalost, ona čine da neki delovi naše planete izgledaju kao Mesec. Korišćenje fosilnih goriva upetljava nas u konflikt u nestabilnim regionima sveta, i iziskuje novac i ljudske živote.
Things could be very different if we were using thorium. You see, in a LFTR, we could use thorium about 200 times more efficiently than we're using uranium now. And because the LFTR is capable of almost completely releasing the energy in thorium, this reduces the waste generated over uranium by factors of hundreds, and by factors of millions over fossil fuels. We're still going to need liquid fuels for vehicles and machinery, but we could generate these liquid fuels from the carbon dioxide in the atmosphere and from water, much like nature does. We could generate hydrogen by splitting water and combining it with carbon harvested from CO2 in the atmosphere, making fuels like methanol, ammonia, and dimethyl ether, which could be a direct replacement for diesel fuels. Imagine carbon-neutral gasoline and diesel, sustainable and self-produced.
Stvari bi mogle biti drugačije kad bismo koristili torijum. U RTFT-u bismo mogli da koristimo torijum skoro 200 puta efikasnije nego što koristimo uranijum sada. A zbog toga što je RTFT u stanju da skoro potpuno oslobodi energiju iz torijuma, to smanjuje nastali otpad u odnosu na uranijum nekoliko stotina puta, a milion puta u odnosu na fosilna goriva. I dalje će nam trebati tečna goriva za vozila i mašine, ali mogli bismo proizvesti tečna goriva od ugljen-dioksida iz atmosfere i iz vode, kao priroda što radi. Mogli bismo da proizvodimo vodonik razdvajanjem vode i kombinujući ga sa ugljenikom dobijenog od ugljen-dioksida iz atmosfere, praveći goriva kao što su metanol, amonijak i dimetil etar, koji bi mogli biti zamena za dizel-goriva. Zamislite benzin i dizel bez emisije ugljen-dioksida, koji su održivi i koji se sami stvaraju.
Do we have enough thorium? Yes, we do. In fact, in the United States, we have over 3,200 metric tons of thorium that was stockpiled 50 years ago and is currently buried in a shallow trench in Nevada. This thorium, if used in LFTRs, could produce almost as much energy as the United States uses in three years. And thorium is not a rare substance, either. There are many sites like this one in Idaho, where an area the size of a football field would produce enough thorium each year to power the entire world.
Imamo li dovoljno torijuma? Da, imamo. U stvari, u SAD-u imamo preko 3 200 metričkih tona torijuma koji je nagomilan pre 50 godina i koji je trenutno zakopan u površnom rovu u Nevadi. Ovaj torijum bi, kada bi se koristio u RTFT-u, mogao da proizvede skoro onoliko energije koliko Amerika iskoristi za tri godine. A torijum nije retka supstanca. Postoji puno nalazišta kao što je ovaj u Ajdahu, gde bi površina fudbalskog terena proizvela dovoljno torijuma svake godine da obezbedi energiju za ceo svet.
Using liquid fluoride thorium technology, we could move away from expensive and difficult aspects of current water-cooled, solid-fueled uranium nuclear power. We wouldn't need large, high-pressure nuclear reactors and big containment buildings that they go in. We wouldn't need large, low-efficiency steam turbines. We wouldn't need to have as many long-distance power transmission infrastructure, because thorium is a very portable energy source that can be located near to where it is needed. A liquid fluoride thorium reactor would be a compact facility, very energy-efficient and safe, that would produce the energy we need day and night, and without respect to weather conditions. In 2007, we used five billion tons of coal, 31 billion barrels of oil and five trillion cubic meters of natural gas, along with 65,000 tons of uranium to produce the world's energy. With thorium, we could do the same thing with 7,000 tons of thorium that could be mined at a single site.
Koristeći tehnologiju tečnog fluoridnog torijuma, mogli bismo da se odmaknemo od skupih i teških aspekata uranijuma koji se hladi vodom i koji koristi čvrsta goriva. Ne bi nam trebali veliki nuklearni reaktori pod visokim pritiskom i velike zaštitne zgrade u koje se stavljaju. Ne bi nam trebale velike parne turbine niske efikasnosti. Ne bismo morali da imamo toliko infrastrukture za transmisiju energije na velike udaljenosti, jer je torijum prenosiv izvor energije, koji se može naći blizu mesta gde je potreban. Reaktor za tečni fluoridni torijum bi bio kompaktno postrojenje, efikasno pri potrošnji energije i bezbedan, koje bi proizvodio energiju koja nam je potrebna bez prestanka, i bez obzira na vremenske uslove. U 2007. godini iskoristili smo pet milijardi tona uglja, 31 milijardu buradi ulja, pet biliona kubnih metara prirodnog gasa, sa sve 65 000 tona uranijuma kako bismo proizveli energiju u svetu. Sa torijumom bismo mogli da uradimo istu stvar, sa 7 000 tona torijuma koje se mogu iskopati na jednom nalazištu.
If all this sounds interesting to you, I invite you to visit our website, where a growing and enthusiastic online community of thorium advocates is working to tell the world about how we can realize a clean, safe and sustainable energy future, based on the energies of thorium.
Ako vam sve ovo zvuči interesantno, pozivam vas da posetite naš sajt, gde sve veća i entuzijastična onlajn zajednica pristalica torijuma radi na tome da kaže svetu o tome kako možemo da stvorimo čistu i sigurnu budućnost održive energije zasnovane na energiji torijuma.
Thank you very much. (Applause)
Hvala vam puno. (Aplauz)