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With a half-life of 432 years, the americium-241 in an ionization smoke detector includes about 3% neptunium after 20 years, and about 15% after 100 years. Under oxidizing conditions, neptunium-237 is the most mobile actinide in the deep geological repository environment of the Yucca Mountain project in Nevada . [ 154 ]
Neptunium-239 has 146 neutrons and a half-life of 2.356 days. It is produced via β − decay of the short-lived uranium-239 , and undergoes another β − decay to plutonium-239 . This is the primary route for making plutonium, as 239 U can be made by neutron capture in uranium-238 .
This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds. [1]
Half-life range Fission products of 235 U by yield [2] 4n 4n + 1 4n + 2 4n + 3 4.5–7% 0.04–1.25% <0.001% 228 Ra № 4–6 a: 155 Eu þ: 248 Bk [3] > 9 a: 244 Cm ƒ: 241 Pu ƒ: 250 Cf 227 Ac № 10–29 a: 90 Sr 85 Kr 113m Cd þ: 232 U ƒ: 238 Pu ƒ: 243 Cm ƒ: 29–97 a: 137 Cs 151 Sm þ: 121m Sn 249 Cf ƒ: 242m Am ƒ: 141–351 a No ...
The isobar forming 132 Te/ 132 I is: Tin-132 (half-life 40 s) decaying to antimony-132 (half-life 2.8 minutes) decaying to tellurium-132 (half-life 3.2 days) decaying to iodine-132 (half-life 2.3 hours) which decays to stable xenon-132. The creation of tellurium-126 is delayed by the long half-life (230 k years) of tin-126.
Spectral lines of neptunium: Other properties; Natural occurrence: from decay: Crystal structure ... half-life (t 1/2) mode product; 235 Np synth: 396.1 d:
Actinium-225 has a half-life of 10 days and decays by alpha emission. It is part of the neptunium series, for it arises as a decay product of neptunium-237 and its daughters such as uranium-233 and thorium-229. It is the last nuclide in the chain with a half-life over a day until the penultimate product, bismuth-209 (half-life 2.01 × 10 19 ...
The back-end of the nuclear fuel cycle, mostly spent fuel rods, contains fission products that emit beta and gamma radiation, and actinides that emit alpha particles, such as uranium-234 (half-life 245 thousand years), neptunium-237 (2.144 million years), plutonium-238 (87.7 years) and americium-241 (432 years), and even sometimes some neutron ...