Uranium-235

Uranium-235 occurs naturally in Australia and has the distinction of being the only naturally occurring fissile isotope.

Cheeseburger Gothic » Prepping for Pucka. 2010

In the nuclear process, mildly radioactive uranium is taken from the ground and bombarded by neutrons -- and that part of the uranium which can split, "fissile," Uranium-235, is transformed into radioactive twins of safe and stable elements in nature: There are hundreds of these "fission products."

Karl Grossman: Nuclear Power Can Never Be Made Safe Karl Grossman 2011

In the nuclear process, mildly radioactive uranium is taken from the ground and bombarded by neutrons -- and that part of the uranium which can split, "fissile," Uranium-235, is transformed into radioactive twins of safe and stable elements in nature: There are hundreds of these "fission products."

Karl Grossman: Nuclear Power Can Never Be Made Safe Karl Grossman 2011

The Uranium-235 kernel of the atomic bomb was close to thermal equilibrium, chilled as infrared carried away the last of the frictional heat from the missile ripping through atmosphere on ascent, warmed by inexorable slow fission.

MIND MELD: The Best Spaceships in Written Science Fiction 2010

The floating nuclear plants would use a far more volatile fuel than land-based plants: weapons-grade uranium containing 40 percent Uranium-235.

Karl Grossman: Floating Chernobyls 2010

Uranium-235 makes up only 0.7% of the natural ore.

There Is No Such Thing as Nuclear Waste 2009

Uranium-235 (235U) is of even greater importance because it is the key to utilizing uranium.

Uranium 2009

Uranium-235 can be concentrated by gaseous diffusion and other physical processes, if desired, and used directly as a nuclear fuel, instead of natural uranium, or used as an explosive.

Uranium 2009

Some things have insanely short half-lives — the subatomic particles that are produced in atom smashers like the LHC often have half-lives measured in minute fractions of a second — while others have half lives measured in millenia — the half-life of Uranium-235 nucleii is over 700 million years.

Equation Answers 2008

As for Iran comprising a nuke threat, the IAEA inspectors didn†™ t even find trace amounts of almost pure Uranium-235, much less the hundreds of pounds that would be needed to make a few first-generation nukes.

Think Progress » Progress on Iran diplomacy? 2006