World Library  
Flag as Inappropriate
Email this Article


Article Id: WHEBN0012127712
Reproduction Date:

Title: Plutonium-244  
Author: World Heritage Encyclopedia
Language: English
Subject: Primordial nuclide, List of elements by stability of isotopes, Trace radioisotope, Stable nuclide, Isotopes of plutonium
Publisher: World Heritage Encyclopedia


Plutonium-244 (244Pu) is an isotope of plutonium that has a half-life of 80 million years. This is longer than any of the other isotopes of plutonium and longer than any other actinide isotope except for the three naturally abundant ones: uranium-235 (704 million years), uranium-238 (4.468 billion years), and thorium-232 (14.05 billion years).

Accurate measurements, beginning in the early 1970s, have detected primordial plutonium-244,[1] making it the shortest-lived primordial nuclide. The amount of 244Pu in the pre-Solar nebula (4.57×109 years ago) was estimated as 0.008 of amount of 238U.[2] As the age of the Earth is about 57 half-lives of 244Pu, the amount of plutonium-244 left should be very small; Hoffman et al. estimated its content in the rare-earth mineral bastnasite as c244=1.0×10−18 g/g, which corresponded to the content in the Earth crust as low as 3×10−25 g/g[1] (i.e. the total mass of plutonium-244 in the Earth crust is about 9 g). Since plutonium-244 cannot be easily produced by natural neutron capture in the low neutron activity environment of uranium ores (see below), its presence cannot plausibly be explained by any other means than creation by r-process nucleosynthesis in supernovae. Plutonium-244 is thus the shortest-lived and heaviest primordial isotope yet detected or theoretically predicted.

However, the detection of primordial 244Pu in 1971 is not confirmed by recent, more sensitive measurements[2] using the method of accelerator mass spectrometry. In this study, no traces of plutonium-244 in the samples of bastnasite (taken from the same mine as in the early study) were observed, so only an upper limit on the 244Pu content was obtained: c244 < 0.15×10−18 g/g, which is 370 (or less) atoms per gram of the sample, at least 7 times lower than the abundance measured by Hoffman et al..

Unlike plutonium-238, plutonium-239, plutonium-240, plutonium-241, and plutonium-242, plutonium-244 is not produced in quantity by the nuclear fuel cycle, because further neutron capture on plutonium-242 produces plutonium-243 which has a short halflife (5 hours) and quickly beta decays to americium-243 before having much opportunity to further capture neutrons in any but very high neutron flux environments. However, a nuclear weapon explosion can produce some plutonium-244 by rapid successive neutron capture.


  1. ^ a b D. C. Hoffman, F. O. Lawrence, J. L. Mewherter, F. M. Rourke: "Detection of Plutonium-244 in Nature", in: Nature 1971, 234, 132–134; doi:10.1038/234132a0.
  2. ^ a b J. Lachner et al. Attempt to detect primordial 244Pu on Earth. Phys. Rev. C 85 (2012) 015801. doi:10.1103/PhysRevC.85.015801
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.