For 10 points, name this metal whose fissile 235 isotope fuels nuclear reactors.
When cooled to 17 kelvins, this element's ruthenium silicide unusually releases a burst of heat, breaking double time-reversal symmetry. The AVLIS method uses tunable dye lasers to detect minute differences in hyperfine structure among this element's isotopes. It's not an alkali metal, but this metal's carbonate is very soluble in water at basic pHs, because two terminal oxides and a carbonate group can simultaneously bind to its plus-6 cation ("cat-ion"). Two parallel decay chains in zircon from this element to different isotopes of lead enable a common kind of radiometric dating. Its hexafluoride is either forced through a semipermeable membrane in gaseous diffusion or is spun at high speeds in a gas centrifuge during the process of its "enrichment" from yellowcake. For 10 points, name this metal whose fissile 235 isotope fuels nuclear reactors.
When cooled to 17 kelvins, this element's ruthenium silicide unusually releases a burst of heat, breaking double time-reversal symmetry.
uranium [or U] &lt;Chemistry&gt;