unfissionable
Cannot be split
Unable to undergo nuclear fission—the splitting of atomic nuclei that releases enormous energy.
Some isotopes are naturally unfissionable; others require conditions that make fission impractical.
The term appears in nuclear physics and policy discussions about which materials can or cannot be weaponized: The reactor uses unfissionable uranium-238 as a matrix for the fissile material.
Predominant uranium isotope
- cross-sectionView through interior
- isotopeElemental variant by mass
- actinideHeavy radioactive metal series
- transuranicHeavier than element 92
nucleus · radioactive · decay · half-life · transmutation · moderator · enrichment · subcritical
Predominant uranium isotope
Chemically inactive or stable
- resistantWithstanding external forces
- durableAble to withstand use
- unchangingNot varying at all
- immutableIncapable of being changed
persistent · inert · unreactive · long-lived · robust · secure · fixed · unbreakable
uranium-238
Predominant uranium isotope
- cross-sectionView through interior
- isotopeElemental variant by mass
- actinideHeavy radioactive metal series
transuranic · nucleus · radioactive · decay · half-life · transmutation · moderator · enrichment · subcritical
uranium-238
Predominant uranium isotope
- neptuniumSynthetic radioactive metallic element
- americiumElement ninety-five, synthetic actinide
- curiumRadioactive actinide, atomic ninety-six
berkelium · californium · einsteinium · fermium · even-numbered
non-reactive
Chemically inactive or stable
- resistantWithstanding external forces
- durableAble to withstand use
- unchangingNot varying at all
immutable · persistent · inert · unreactive · long-lived · robust · secure · fixed · unbreakable · indivisible
unfissionablefissionable
Able to split atomically
fissile · weapons-grade · enriched · critical · subcritical