Nuclear fission binding energy

C22-0029. Write a paragraph summarizing the important features of each of the following topics (a) nuclear stability (b) nuclear decay (c) fission (d) fusion and (e) binding energy. 

Owing to the difficulty in separating Ba and Ra cleanly, Hahn erroneously attributed Ra radioactivity to Ba and thereby passed over the discovery of nuclear fission see Binding Energy of Nuclei). His sample of BaS04 was not the pure Ba compound, and the unknown Ra contaminant led to his observation and incorrect conclusion. 

Not all properties of the nuclei can be explained by the shell model. For calculation of binding energies and the description of nuclear reactions, in particular nuclear fission, the drop model of the nucleus has proved to be very useful. In this model it is assiuned that the nucleus behaves hke a drop of a liquid, in which the nucleons correspond to the molecules. Characteristic properties of such a drop are cohesive forces, surface tension, and the tendency to split if the drop becomes too big. 

For the use of nuclides as nuclear fuel, their fissionability is the most important aspect. High fission yields by thermal neutrons are obtained if the binding energy of an additional neutron is higher than the fission barrier. Fission barriers, neutron binding energies and fission cross sections are listed for some nuclides in Table 11.1. The fission cross sections are high for and Pu, as already mentioned in... 

The SNF portion of HLW can be understood by chemists who see in it nearly every element on the periodic chart of the elements. After a 235u nucleus undergoes fission and releases its excess nuclear binding energy, it leaves a pair of new atoms. These fission products are like newly born forms of the elements that are already well known and, like newborns, are unstable until they mature. There are about 1000 isotopes of about 100 different elements in SNF, and most are radioactive. They decay into stable elements at different rates, giving off alpha, beta, and gamma emissions. It will take about 7000 years until the SNF will be only as radioactive as the rocks and minerals that make up our planet. 

Describe the general trend in the variation in binding energy per nucleon for the natural nuclides, and use it to explain how energy is released in both nuclear fusion and nuclear fission. 

Nuclear binding energy, p. 908 Nuclear chain reaction, p. 917 Nuclear fission, p. 916 Nuclear fusion, p. 923... 

The mass of a nucleus is less than the sum of the masses of its nucleons by an amount called the mass defect. The energy equivalent to the mass defect is the nuclear binding energy, usually expressed in units of MeV. The binding energy per nucleon is a measure of nuclide stability and varies with the number of nucleons in a nuclide. Nuclides with A == 60 are most stable. Lighter nuclei can join (fusion) or heavier nuclei can split (fission) to become more stable. 

Explain the mass defect and how it is related to nuclear binding energy understand how nuclear stability is related to binding energy per nucleon and why unstable nuclides undergo either fission... 

---