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Atomic number (Z) 62: Group: f-block groups ... Samarium-149 is an ... Its neutron cross section is 41000 barns for thermal neutrons. [73] Because samarium-149 is not ...
The stable fission product 149 Sm is also a neutron poison. Samarium is theoretically the lightest element with even atomic number with no stable isotopes (all isotopes of it can theoretically go either alpha decay or beta decay or double beta decay), other such elements are those with atomic numbers > 66 (dysprosium, which is the heaviest ...
Samarium-149 is the second most important neutron poison in nuclear reactor physics. Samarium-151, produced at lower yields, is the third most abundant medium-lived fission product but emits only weak beta radiation. Both have high neutron absorption cross sections, so that much of them produced in a reactor are later destroyed there by neutron ...
Samarium: Europium: Gadolinium: Terbium: Dysprosium: ... The average number of neutrons per fission from the 312 124 compound nucleus ... 149 pm 152 pm 158 pm 250 pm ...
An even number of protons or neutrons is more stable ... samarium: 5: 2 152 Sm: 154 Sm: 147 Sm: 149 Sm: 148 Sm: 150 Sm: 144 Sm: 76:
beta decays to very long lived Samarium-147 (half life>age of the universe); has seen some use in radioisotope thermoelectric generators: 1.0888%: Samarium: 149 Sm: Observationally stable: 2nd most significant neutron poison. 0.9% [3] Iodine: 129 I: 15.7 My: Long-lived fission product. Candidate for disposal by nuclear transmutation. 0.4203% ...
149 Sm 13.8% stable 150 Sm 7.37% ... The number willbe rounded to 3 sigfig. ... Two neutrons ejected from nucleus simultaneously.
Some fission products decay with the release of delayed neutrons, important to nuclear reactor control. Other fission products, such as xenon-135 and samarium-149, have a high neutron absorption cross section. Since a nuclear reactor must balance neutron production and absorption rates, fission products that absorb neutrons tend to "poison" or ...