Page 186 - Physics 10_Float

ATOMIC AND NUCLEAR PHYSICS

reaction is not controlled, it will proceed too rapidly and
possibly results in the sudden release of an enormous
amount of energy (an explosion).

235
U
92
Ba
Ba
Uranium nucleus
235 235
U U
92 92
Ba
Neutron Ba
Ba
Ba
235
Neutrons U
92
Ba
Ba
Fig. 18.12: Fission Chain reaction in U-235
This fission chain reaction is controlled in nuclear reactors. A
nuclear reactor provides energy for useful purposes. In this
sort of self sustained reaction, extra neutrons liberated in
fission reactions are absorbed using some material to slow
down the chain reaction.

Half-lives of Selected Isotopes

Element Isotope Half-Life Radiation
Produced

Hydrogen 0 1 H 12.3 years 
14 
Carbon 6 C 5730 years
14
Cobalt 6 Co 30 years 
131
Lodine 53 I 8.07 days 
212
Lead 82 Pb 10.6 hours 
194 Po
Polonium 84 0.7 seconds 
210 Po
Polonium 84 138 days 
235 U
8
Uranium 92 7.1 x 10 years 
238 U
9
Uranium 236 92 Pu 4.51 x 10 years 
Plutonium 242 94 2.85 years 
94 Pu 5
Plutonium 3.79 x 10 years 

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