Warum Uran 235 und nicht 238?
Das Schwermetall Uran liegt natürlicherweise in unterschiedlichen Atomsorten (Isotopen) vor: Zu 99,3 Prozent als U 238. Diese Sorte enthält im Atomkern 92 Protonen und 146 Neutronen, macht zusammen 238 Kernbausteine. Nur zu 0,7 Prozent besteht das Metall hingegen aus U 235 mit drei Neutronen weniger.
Wie schreibt man eine Zerfallsgleichung?
Die Zerfallsgleichung sagt voraus, wie viele Teilchen einer radioaktiven Stoffmenge nach der Zeit t noch nicht zerfallen sind. Ihre Formel lautet: Die Teilchenzahl N zum Zeitpunkt t ist N(t)=N0×e-λ×t. Oder, anders geschrieben, N(t)=N0×½t/(T½).
What happened to U235 U-235?
After training with the 5th U-boat Flotilla at Kiel, U-235 was transferred to the 22nd flotilla on 29 October 1943, following her sinking in May by US bombs in Kiel. She had been raised, repaired and returned to service.
Why is nuclear fission possible in U-235?
All neutrons can cause fission in U-235, so its reaction is sustainable. The requirement for a material to be fissile (to be able to sustain a chain fission reaction) is not simply that it have neutrons, but that each fission releases enough neutrons of the right energy to trigger further reactions.
What is the difference between uranium U238 and U235?
There are 3 isotopes of uranium that can be found in nature [1]: U234, U235 and U238. For a chain reaction to last there must be a high amount of neutrons contents and by comparison, U238 contains 92 protons and 146 neutrons [2] while U235 contains 92 protons and 143 neutrons [3]. My question is why not use U238?
Why is U235 so hard to break up?
U-235, on the other hand, is very sensitive to being broken up by slow neutrons (almost 600 times more sensitive according to Wikipedia ). Moreover, it often releases multiple neutrons when breaking up. And it is easier to slow down too-fast neutrons (this is what moderators do) than to speed up too-slow ones.