![]() Beta decay Kr-85→ Rb, Sr-90→ Zr, Ru-106→ Pd, Sb-125→ Te, Cs-137→ Ba, Ce-144→ Nd, Sm-151→ Eu, Eu-155→ Gd visible.īecause of the stability of nuclei with even numbers of protons and/or neutrons the curve of yield against element is not a smooth curve. Yields at 10 0,1,2,3 years after fission, not considering later neutron capture, fraction of 100% not 200%. Colors indicate fluoride volatility, which is important in nuclear reprocessing: Blue elements have volatile fluorides or are already volatile green elements do not but have volatile chlorides red elements have neither, but the elements themselves are volatile at very high temperatures. Ternary fission, about 0.2–0.4% of fissions, also produces a third light nucleus such as helium-4 (90%) or tritium (7%). Less often, it is stated as percentage of all fission products, so that the percentages sum to 100%. Yield is usually stated as percentage per fission, so that the total yield percentages sum to 200%. ![]() Chain yields do not account for these "shadowed" isotopes however, they have very low yields (less than a millionth as much as common fission products) because they are far less neutron-rich than the original heavy nuclei. Isotope and element yields will change as the fission products undergo beta decay, while chain yields do not change after completion of neutron emission by a few neutron-rich initial fission products ( delayed neutrons), with half-life measured in seconds.Ī few isotopes can be produced directly by fission, but not by beta decay because the would-be precursor with atomic number one greater is stable and does not decay. Known as "chain yield" because it represents a decay chain of beta decay.
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