Distinction between Fissionable, Fissile and Fertile

  • Fissile materials are a subset of fissionable materials.
  • Fissionable material consist of isotopes that are capable of undergoing nuclear fission after capturing either fast neutron (high energy neutron – let say >1 MeV) or thermal neutron (low energy neutron – let say 0.025 eV).   Typical fissionable materials: 238U, 240Pu, but also 235U, 233U, 239Pu, 241Pu
  • Fissile material consist of fissionable isotopes that are capable of undergoing nuclear fission only after capturing a thermal neutron. 238is not fissile isotope, because 238U cannot be fissioned by thermal neutron. 238does not meet also alternative requirement to fissile materials. 238U is not capable of sustaining a nuclear fission chain reaction, because neutrons produced by fission of 238U have lower energies than original neutron (usually below the threshold energy of 1 MeV). Typical fissile materials: 235U, 233U, 239Pu, 241Pu.
  • Fertile material consist of isotopes that are not fissionable by thermal neutrons, but can be converted into fissile isotopes (after neutron absorption and subsequent nuclear decay). Typical fertile materials: 238U, 232Th.

See also: Neutron cross-section

Fissile / Fertile Material Cross-sections
Fissile / Fertile Material Cross-sections. Comparison of total fission cross-sections.
Source: JANIS (Java-based Nuclear Data Information Software)
http://www.oecd-nea.org/janis/
Fissile / Fertile Material Cross-sections
Fissile / Fertile Material Cross-sections. Comparison of total fission cross-sections.
Source: JANIS (Java-based Nuclear Data Information Software)
http://www.oecd-nea.org/janis/

Comparison of cross-sections

Source: JANIS (Java-based nuclear information software)  http://www.oecd-nea.org/janis/

Fissionable – Non-Fissile

Fissile / Fertile Material Cross-sections
Uranium 238 cross-sections
Source: JANIS (Java-based nuclear information software)
http://www.oecd-nea.org/janis/
Fissile / Fertile Material Cross-sections
Plutonium 240 cross-sections Source: JANIS (Java-based nuclear information software)
http://www.oecd-nea.org/janis/

Fissionable – Fissile

Fissile / Fertile Material Cross-sections
Uranium 235 cross-sections Source: JANIS (Java-based nuclear information software)
http://www.oecd-nea.org/janis/
Fissile / Fertile Material Cross-sections
Uranium 233 – cross-sections
Source: JANIS (Java-based nuclear information software)
http://www.oecd-nea.org/janis/
Fissile / Fertile Material Cross-sections
Plutonium 239 – cross-sections
Source: JANIS (Java-based nuclear information software)
http://www.oecd-nea.org/janis/
Fissile / Fertile Material Cross-sections
Plutonium 241 – cross-sections.
Source: JANIS (Java-based nuclear information software)
http://www.oecd-nea.org/janis/

Fertile

Fissile / Fertile Material Cross-sections
Uranium 238 cross-sections.
Source: JANIS (Java-based nuclear information software)
http://www.oecd-nea.org/janis/
Fissile / Fertile Material Cross-sections
Thorium 232 cross-sections. Source: JANIS (Java-based nuclear information software)
http://www.oecd-nea.org/janis/

See above:

Glossary