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fission products
135Cs2.3 6.3333269
107Pd6.5 .162933
129I15.7 .6576194γ

Palladium-107 is the second longest lived (halflife of 6.5 million years) and least radioactive (decay energy only 33 KeV, specific activity 5×10-5 Ci/g) of the 7 long-lived fission products. It undergoes pure beta decay (no gamma radiation) to silver-107.

Its yield from thermal neutron fission of uranium-235 is 0.1629% per fission, only 1/4 that of iodine-129, and only 1/40 those of Tc-99, Zr-93, and Cs-135. Yield from U-233 is slightly lower, but yield from Pu-239 is much higher, 3.3%. Yields are higher in fast fission or in fission of heavier nuclei.

According to [1] fission palladium contains the isotopes 104Pd (16.9%), 105Pd (29.3%), 106Pd (21.3%), 107Pd (17%), 108Pd (11.7%) and 110Pd (3.8%). According to another source, the proportion of 107Pd is 9.2% for palladium from thermal neutron fission of U-235, 11.8% for U-233, and 20.4% for Pu-239. (and the Pu-239 yield of palladium is about 10 times that of U-235.)

Because of this dilution and because 105Pd has 11 times the neutron absorption cross section, 107Pd is not amenable to disposal by nuclear transmutation. However, as a noble metal, palladium is not as mobile in the environment as iodine or technetium.


  1. ^ [1]

See also

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Palladium-107". A list of authors is available in Wikipedia.
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