Search results
Results from the WOW.Com Content Network
Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235 U) has been increased through the process of isotope separation.Naturally occurring uranium is composed of three major isotopes: uranium-238 (238 U with 99.2732–99.2752% natural abundance), uranium-235 (235 U, 0.7198–0.7210%), and uranium-234 (234 U, 0.0049–0.0059%).
The U.S. Nuclear Regulatory Commission (NRC) approved a license amendment allowing GLE to operate the Test Loop. Also in 2008, Cameco Corporation, Canada, the world's largest uranium producer, joined GE and Hitachi as a part owner of GLE. [8] In 2010, concerns were raised that the SILEX process poses a threat to global nuclear security. [9]
TRIGA fuel was originally designed to use highly enriched uranium, however in 1978 the U.S. Department of Energy launched its Reduced Enrichment for Research Test Reactors program, which promoted reactor conversion to low-enriched uranium fuel. There are 35 TRIGA reactors in the US and an additional 35 in other countries.
Isotope separation is the process of concentrating specific isotopes of a chemical element by removing other isotopes. The use of the nuclides produced is varied. The largest variety is used in research (e.g. in chemistry where atoms of "marker" nuclide are used to figure out reaction mechanisms).
If natural uranium is enriched to 3% U-235, it can be used as fuel for light water nuclear reactors. If it is enriched to 90% uranium-235, it can be used for nuclear weapons. Diagram of the principles of a Zippe-type gas centrifuge with U-238 represented in dark blue and U-235 represented in light blue.
A nuclear fuel pellet Nuclear fuel pellets that are ready for fuel assembly completion. The use of ordinary water makes it necessary to do a certain amount of enrichment of the uranium fuel before the necessary criticality of the reactor can be maintained. The light-water reactor uses uranium 235 as a fuel, enriched to approximately 3 percent.
Nuclear reactors with water moderator require at least some enrichment of 235 U. Nuclear reactors with heavy water or graphite moderation can operate with natural uranium, eliminating altogether the need for enrichment and preventing the fuel from being useful for nuclear weapons; the CANDU power reactors used in Canadian power plants are an ...
To improve the fuel's sensitivity to neutrons, a neutron moderator is used, in this case highly purified graphite. [2] [3] The reactors consisted of a huge cube of this material (the "pile") made up of many smaller blocks and drilled through horizontally to make a large number of fuel channels. Uranium fuel was placed in aluminium canisters and ...