Do Neptunium and plutonium occur in nature?

Conventional wisdom tells us that plutonium (Pu) does not exist in nature. Plutonium and other ... But in the strictest sense, the answer to the question is yes, plutonium does occur naturally. Plutonium appears at ... It was the second transuranic element to be discovered; neptunium (Np) was identified in 1940. read more

One isotope each of neptunium and plutonium have been found in uranium ore: Np-237 (half life 2.144 million years) and Pu-239 (half life 24,110 years). The concentration of these nuclides is best expressed as its ratio to the uranium content of the ore. read more

Thus, they assume that when plutonium is found in the environment, human technology has put it there. This element has usually been considered synthetic because it is produced most efficiently in nuclear reactors. But in the strictest sense, the answer to the question is yes, plutonium does occur naturally. read more

However, as neptunium does in fact occur in nature in trace amounts, as demonstrated when it was found in uranium ore in 1952, it is possible that Hulubei and Cauchois did in fact observe neptunium. read more

Neptunium is found in a ratio of about one part in a trillion; the plutonium ratio ranges from about 1 to 15 parts per trillion. Both of these exist because of continuous formation through the capture of spontaneous fission neutrons emitted by U-238 by uranium isotopes in the ore. read more

But in the strictest sense, the answer to the question is yes, plutonium does occur naturally. Plutonium appears at very low concentrations in nature, on the order of one part in 10 11 in pitchblende, the ore of uranium (U). read more