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Even though americium-241 produces less heat and electricity than plutonium-238 (the power yield is 114.7 milliwatts per gram [3.25 watts per ounce] for 241 Am vs. 570 mW/g [16 W/oz] for 238 Pu) [17] and its radiation poses a greater threat to humans owing to gamma and neutron emission, it has advantages for long duration missions with its ...
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]
Americium-243 has a mass of 243.06138 g/mol and a half-life of 7,370 years, the longest lasting of all americium isotopes. It is formed in the nuclear fuel cycle by neutron capture on plutonium-242 followed by beta decay . [ 15 ]
There are two long-lived alpha-emitters; 243 Am has a half-life of 7,370 years and is the most stable isotope, and 241 Am has a half-life of 432.2 years. The most stable nuclear isomer is 242m1 Am; it has a long half-life of 141 years. The half-lives of other isotopes and isomers range from 0.64 microseconds for 245m1 Am to 50.8 hours for 240 ...
Natural uranium is made weapons-grade through isotopic enrichment. Initially only about 0.7% of it is fissile U-235, with the rest being almost entirely uranium-238 (U-238). They are separated by their differing masses. Highly enriched uranium is considered weapons-grade when it has been enriched to about 90% U-235. [citation needed]
A fission product is a nucleus with approximately half the mass of a uranium or plutonium nucleus which is left over after such a nucleus has been "split" in a nuclear fission reaction. Caesium-137 is one such radionuclide. It has a half-life of 30 years, and decays by beta decay without gamma ray emission to a metastable state of barium-137 ...
The most important isotopes of these elements in spent nuclear fuel are neptunium-237, americium-241, americium-243, curium-242 through -248, and californium-249 through -252. Plutonium and the minor actinides will be responsible for the bulk of the radiotoxicity and heat generation of spent nuclear fuel in the long term (300 to 20,000 years in ...
After removal of fuel from reactor, decay will predominate for shorter-lived isotopes such as 238 Pu, 241 Pu, 242–244 Cm; but 245–248 Cm are all long-lived. Fertile material is a material that, although not fissile itself, can be converted into a fissile material by neutron absorption .