Isotopes of uranium

Uranium has several isotopes, but the most significant ones are: 1. **Uranium-238 (U-238)**: This is the most abundant isotope of uranium, comprising about 99.3% of natural uranium. U-238 is not fissile (cannot sustain a nuclear chain reaction) but can be converted into plutonium-239 in a reactor environment. 2. **Uranium-235 (U-235)**: This isotope constitutes about 0.