from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of a series of chemically similar, radioactive elements with atomic numbers ranging from 89 (actinium) through 103 (lawrencium).
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of the 14 radioactive elements of the periodic table that are positioned under the lanthanides to which they have similar chemistry.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. any of a series of radioactive elements with atomic numbers 89 through 103
They do, however, create actinide-free waste that is much less radioactive, with a half-life of a couple of hundred years (as opposed to tens of thousands of years for LWR waste).
In other words, the fissile material produced by these reactors is recycled at least twice until the final waste results in an actinide-free byproduct that has a half life of about 200 years.
Depending upon which chemist you ask, rare earth elements consist of either: the so-called lanthanide series (elements having atomic numbers from 57 [corresponding to lanthanum] to 71 [corresponding to lutetium]) or the actinide (elements 89 to 103) and lanthanide series.
Considering the closed fuel cycle, Generation I-III reactors recycle plutonium (and possibly uranium), while Generation IV designs are expected to have full actinide recycling capability.
In this, up to ten percent of the neutrons could come from the spallation, though it would normally be less, even where actinide incineration is the main objective.
Here, the blanket assembly is actinide fuel and/or spent nuclear fuel.
This can become plutonium-239 (239Pu) and by successive neutron capture 240Pu, 241Pu and 242Pu as well as other transuranic or actinide isotopes.
The actinide mix is then burned in on-site fast reactors.
Fuel used is of depleted uranium metal or nitride, with full actinide recycled from regional or central reprocessing plants.
However, it can be built as a fast reactor with full actinide recycling based on conventional reprocessing.
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