Question

Check that the nuclides ²³⁹Pu, ²³³U, and ²⁴¹Pu satisfy the four conditions listed in §18.3.3 for being fissile. A few other actinides Z > 92– nuclei with – produced in reactors are also fissile. See if you can find one or two. Check out the isotopes of curium (Z = 96) and/or californium (Z = 98). Explain what information you would need in order to decide for sure if a given nuclide is fissile.

 

 

Answer 1

A nuclide is a kind of atom that is characterized by its number of protons, neutrons, and nuclear energy state.

 

Fissile nuclides are those that undergo slow neutron-induced fission. Fissile materials are the easiest to use in the power generation.

 

Fertile nuclides are those that can be bred into fissile nuclides by neutron capture.

 

Fissionable nuclides are those that can be fission by neutrons of certain energy.

 

The primary distinction between fissile and fertile isotopes: fissile isotopes are materials that may undergo fission reactions, whereas fertile isotopes can be converted into fissile isotopes. As a result, all fissile nuclei are fissionable, but not the other way around.

 

The only naturally existing fissile nuclide is 235U. Manmade fissile nuclides such as 233U, 239Pu, and 241Pu may be produced from the fertile nuclides 232Th and 238U, respectively. Other fissile actinides, heavier and shorter-lived, are produced in small quantities in fission reactors.

 

There are 14 isotopes of curium identified. They range in mass from 237 and 251 kg. A 247Cm has a half-life of roughly 15,600,000 years, despite the fact that none of them are stable.

 

With mass numbers ranging from 237 to 256, Californium contains 20 isotopes with known half-lives. There are no naturally occurring isotopes of Californium.

 

The fission cross section indicates if an isotope is fissile or merely fertile slow or thermal neutron. When it interacts with an atom, it might be dispersed or absorbed. Fissionable isotopes have high neutron fission cross sections but low absorption cross sections.

 

Curium is a 96th atomic number artificial element. It has no stable isotopes and cannot be given a standard atomic weight because it is an artificial element. In 1944, the isotope 242Cm, which contains 146 neutrons, was synthesized for the first time.

 

Only some nuclides of elements with an atomic number are greater than 90 have low enough threshold energies for effective energy production. Californium-252, for example, is a very unstable heavy nuclide that spontaneously fissions.

 

The nuclide is considered to be fissile when this energy alone is sufficient to produce fission.

 

The actinides with an even number of neutrons in their nucleus have a fission cross section with little or no probability of subthreshold fission.

 

The isotopes of Curium and Californium has fissile nuclide.

The isotopes of Curium and Californium has fissile nuclide.