(or the equivalent in different chemical forms) (para.
Since this characteristic of U-235
was discovered when the Second World War was raging, all efforts were aimed at enriching the material for weapon use.
Cascades are linked networks of centrifuge machines that spin uranium gas to increase the concentration of U-235
, the isotope used in nuclear fission chain reactions, which is found in nature at concentrations of less than 1 percent.
Iranhas been enriching uranium to 20 per cent concentration of the fissile U-235
isotope since early 2010, stoking Western alarm over the nature of its nuclear programme.
At maximum output, this is sufficient capacity to enrich enough weapons grade uranium (90% enriched U-235
) to produce at least 10 warheads per year (assuming the Iranians use 20 kilograms of U-235
The White House obviously felt that the breeder was worth the risks and accepted the AEC's position that U-235
would be in short supply, putting existing fight-water reactors in jeopardy.
Both the Siemens controller/controller software and the Vacon/Fararo Paya frequency converters were directly targeted by the Stuxnet worm, which changed the spin rate of the centrifuges so they were unable to separate U-235
First, during the talks in Baghdad, the P5 1 might seek an early confidence-building agreement by which Iran voluntarily ceases enriching to 20 percent content in the U-235
fissile isotope and blends down or ships out their stockpile of such uranium, which is closer to weapons grade.
The threat Iran's nuclear efforts pose are not simply a matter of its present ability to enrich uranium to 20 percent U-235
," Cordesman argues, "and efforts to control its enrichment activities will not halt its ability to move forward in many areas even if its current enrichment facilities and stocks of highly enriched uranium are fully secured.
Iran has reportedly begun the process of enriching uranium fuel to a 20-percent level of U-235
required for a reactor in Tehran that is used to make medical isotopes.
Key elements would include capping Iranian enrichment of uranium at 5 percent U-235
, stopping enrichment in a facility near Qom and providing access for the International Atomic Energy Agency to places and scientists associated with alleged nuclear weapons research.
According to Cosmos magazine: "Unlike U-235
and Pu-239, no matter how much thorium you pack together, it will not start splitting atoms and blow up.