Ten facts about nuclear weapons and the "Megatons to Megawatts" program

Friday again!

This week that means Bergen, and as (almost) always that means FACTS. This week I want to give you ten facts about nuclear weapons and the "Megatons to Megawatts" project - a little "taster" of what my talk tomorrow will be about (I don't know if there will be a live stream yet, but at least the entire confernce will be filmed, and go on-line later - I will of course share the link when it's ready ;) )

1. nuclear weapons have been used against humans two times; Hiroshima August 6th and Nagasaki August 9th, 1945 - hopefully NEVER again
2. both "Little Boy" and "Fat Man" were fission bombs (getting their energy from fission); "Little Boy" was made of highly enriched uranium (uranium-235), and "Fat Man" was made of plutonium(-239)
3. after WWII a nuclear arms race begun between the US and the Sovjet Union, and at one time there were more than 60 000 nuclear weapons in the world
4. a nuclear weapon is ugly, but by mixing the fissile material in it with uranium or thorium, it can be changed into beautiful nuclear fuel (100% normal nuclear fuel for normal reactors) <3
5. the "Megatons to Megawatts" program was an agreement between US and Sovjet/Russia that lasted from 1993 to 2013, where Sovjet made fuel out of their weapons (unfortunately not all of them) and US bought it
6. during those 20 years (1993-2013), 500 tonnes of highly enriched uranium, from 20 000 Russian nuclear weapons have been converted into nuclear fuel and "burned" in reactors (more than 2 weapons destroyed every day!)
7. the electricity generated from these weapons is the same amount as all the electricity in the US in two years(!)
8. weapons uranium (highly enriched uranium) could be mixed with natural uranium to make fuel (as has been done in the program) - or, even better, with thorium
9. if you mix weapons uranium with thorium, you can also recycle the spent fuel; this means that not only do you get rid of horrible weapons, you also get rid of a lot of nuclear waste (WIN WIN :D )
10. today there are around 16 000 nuclear weapons in the world - much better than 65 000 (or whatever the peak number was), but still that's definitely 16 000 too many...:/

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(I bite my lip when I concentrate - haha)

 Now I'm soon off to NHH, where the conference tomorrow will be held, for sound check, and just "feel" the stage. And when I come back to the hotel again, Anders will be here! I'm so incredibly happy he could join me here in Bergen this weekend!!! We're here until Sunday afternoon, so hopefully we'll have time to actually experience something while we're here - any recommendations from my readers?

Anyway: happy weekend to everyone <3

Trinity, Little Boy, and Fat Man

Today is the last day of August - last day of summer 2015.

This August marked the 70 year anniversary for the end of WWII, the very first atomic bomb testing, and the first (and hopefully last!) time nuclear weapons were used against humans.

 

This picture is of Trinity - the first ever test of an atomic bomb/nuclear weapon. The picture is taken around 1 hundredth of a second after detonation of the bomb. The big grey thing is actually a fireball, which is around 200 meter in diameter. Inside the pink circles are trees. Trinity was tested on July 16 1945, and it was the same kind of bomb as the one in Nagsaki (on August 9 1945) - called Fat Man - except it was a little bit smaller.

Little Boy was a uranium bomb (made of highly enriched uranium), and Fat Man was a plutonium bomb (made of plutonium that they produced from natural uranium in a reactor). Together they destroyed the cities of Hiroshima and Nagasaki, and killed around 130 000-250 000 people...

When an atomic bomb explodes, the nuclear force is released, and that is why they are so powerful - and even though it is a horrible and really scary device, it is also extremely fascinating (the nuclear force, that mostly is responsible for keeping all nuclei everywhere together, IS fascinating). Often people believe that nuclear weapons are dangerous because of radioactivity, but it is mainly the extreme explosive force, and the heat that kills people - not radiation.

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Last year I went to Japan to make the short film Sushi and Nuclear (Sushi og Kjernekraft). Going to Hiroshima and actually see the Atomic Bomb Dome made a very strong impression... You can see the English version of the film HERE, and the Norwegian version HERE.

Kjernefysikkhistorie - første sovjetiske bombetest

I dag er det et ikke så hyggelig 65-årsjubileum... 

Den 29. august 1949 gjennomførte Sovjetunionen sin aller første atomprøvesprengning: i det som i dag er Kazakhstan sprengte de bomben med det klingende navnet "RDS-1". RDS-1 liknet på "Fat Man" - bomben som USA detonerte over Nagasaki i 1945; altså en plutoniumsbombe med 22 kilotonn TNT sprengkraft. 

Prøvesprengningen førte til at USA videre utviklet et kraftigere våpen, nemlig det som kalles termonukleære våpen eller hydrogenbombe - altså fusjonsvåpen (dette er også atomvåpen, men kraftigere enn de som feks ble brukt under krigen - som var fisjonsvåpen). Den første hydrogenbomben ble testet i 1952, mens Sovjetunionen testet sin første fusjonsbombe i 1953.

 (Bildene har jeg lånt fra Physics Today)

Ooops, I did it again...(kjernefysikkhistorie)

...jeg får bare skylde på at denne helgen (og dagene før) har stått i flyttingens tegn, og jeg har vel egentlig ikke hatt tid eller hjernekapasitet til å tenke på noe annet - men det slo meg i dag tidlig, da jeg satt og gjorde siste forberedelser til foredraget jeg holdt for de nye fysikkstudentene, at det nettopp var "bombejubileum" :/ 6. august 1945 ble et kjernefysisk våpen for første gang brukt mot mennesker - i Hiroshima, og den 9. august ble kjernefysiske våpen brukt for andre og siste gang mot mennesker - i Nagasaki, i Japan.

Begge bombene var fisjonsvåpen (altså "kun" spalting av tunge atomkjerner) - fusjonsvåpen/hydrogenbomben kom senere, men Hiroshimabomben ("Little Boy") var laget av høyanriket uran, mens Nagasakibomben ("Fat Man") var laget av plutonium.

Uran-235 og plutonium-239 har forskjellige kjernefysiske egenskaper (selv om begge spaltes lett, og egner seg for å få energi fra - enten som brensel, eller som våpen), så "Little Boy" og "Fat Man" var forskjellige typer bomber: 

"Little Boy" var gun-type, mens "Fat Man" var implosion

Jeg kan sikkert skrive mer om forskjellene på uran-235 og plutonium-239, og hvorfor "Fat Man" og "Little Boy" var forskjellige - hvis det er interesse for det?

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Under er mitt bilde av "Atomic Bomb Dome" - en av bygningene som sto igjen etter bombingen av Hiroshima, som jeg tok da jeg var der i vår.

Grunnen til at bygningen står igjen såpass intakt er at den sto på ground zero - altså rett under der bomben ble detonert.