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In a normal thermal reactor, tin-121m has a very low fission product yield; thus, this isotope is not a significant contributor to nuclear waste. Fast fission or fission of some heavier actinides will produce 121m Sn at higher yields. For example, its yield from U-235 is 0.0007% per thermal fission and 0.002% per fast fission. [10]
The sum of the atomic mass of the two atoms produced by the fission of one fissile atom is always less than the atomic mass of the original atom. This is because some of the mass is lost as free neutrons, and once kinetic energy of the fission products has been removed (i.e., the products have been cooled to extract the heat provided by the reaction), then the mass associated with this energy ...
However, since iodine is a component of biological molecules such as thyroid hormones, iodine-131 is of great importance in nuclear medicine, and in medical and biological research as a radioactive tracer. Lanthanum-140 is a decay product of barium-140, a common fission product. It is a potent gamma emitter.
Spontaneous fission arises as a result of competition between the attractive properties of the strong nuclear force and the mutual coulombic repulsion of the constituent protons. Nuclear binding energy increases in proportion to atomic mass number (A), while coulombic repulsion increases with the square of the proton number (Z). Thus, at high ...
In nuclear fission events the nuclei may break into any combination of lighter nuclei, but the most common event is not fission to equal mass nuclei of about mass 120; the most common event (depending on isotope and process) is a slightly unequal fission in which one daughter nucleus has a mass of about 90 to 100 daltons and the other the ...
As such, while all fissile isotopes are fissionable, not all fissionable isotopes are fissile. In the arms control context, particularly in proposals for a Fissile Material Cutoff Treaty , the term fissile is often used to describe materials that can be used in the fission primary of a nuclear weapon. [ 6 ]
The next longer-lived fission product is samarium-151, which has a half-life of 90 years, and is such a good neutron absorber that most of it is transmuted while the nuclear fuel is still being used; however, effectively transmuting the remaining 151 Sm in nuclear waste would require separation from other isotopes of samarium.
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 .