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Plutonium-241



Plutonium-241
General
Name, symbol Plutonium-241,241Pu
Neutrons 147
Protons 94
Nuclide data
Natural abundance 0 (Artificial)
Half-life 14 years
Decay products 241Am

Plutonium-241 (Pu-241) is an isotope of plutonium formed when plutonium-240 captures a neutron. Unlike 240Pu, 241Pu is fissionable, with a neutron absorption cross section about 1/3 greater than 239Pu, and a similar chance of fissioning on neutron absorption, around 73%. Otherwise, neutron capture produces plutonium-242. In general, isotopes of odd mass number are both more likely to absorb a neutron, and more likely to fission on neutron absorption, than isotopes of even mass number.

Additional recommended knowledge

Effects of Pu-241 decay

241Pu has a half-life of 14 years, corresponding to a decay of about 5% of Pu-241 nuclei over a one-year period. The longer spent nuclear fuel waits before reprocessing, the more 241Pu decays to americium-241, which is nonfissionable (except in a fast reactor) and dangerous as a nuclear waste (halflife 432 years). Americium has lower valence and lower electronegativity than plutonium, neptunium or uranium, so in most nuclear reprocessing, Am tends to fractionate not with U, Np, Pu but with the alkaline fission products: lanthanides, strontium, caesium, barium, yttrium, and is therefore not recycled into nuclear fuel unless special efforts are made.

In a thermal reactor, 241Am captures a neutron to become americium-242, which quickly becomes curium-242 (or, 17.3% of the time, 242Pu) via beta decay. Both Cm-242 and Pu-242 are much less likely to absorb a neutron, and even less likely to fission; however, 242Cm is short-lived (halflife 160 days) and almost always undergoes alpha decay to Pu-238 rather than capturing another neutron. In short, Am-241 needs to absorb three neutrons before again becoming a fissile isotope.

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Plutonium-241". A list of authors is available in Wikipedia.
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