I was wondering just how many of the trans Uranic elements are suitable as reactor fuel in their own right (Such as Plutonium) and whether the rest can be incorperated as a sort of MOX to be burned in reactors primarily run on a diferent fuel without causing problems (IYSWIM)
Roughly half of the transuranics, including the even-numbered isotopes of Pu, can only be used as fuel in fast neutron reactors, because they do not fission in a slow (thermal) neutron flux.
In an ordinary light water reactor, these even-numbered transuranics must first absorb a neutron, to become odd-numbered, before they can fission when hit by a slow neutron. So it takes at least 2 neutrons to fission them (more if you take into account leaked neutrons & other losses). Consequently, they do not support a chain reaction in a light water reactor, acting more like a poison that keeps accumulating.
"Actinide burner" is simply a buzz word for a fast neutron reactor -- one that is built without a breeding "blanket" surrounding the core, to produce additional fuel from U-238. In other words, its a type of fast reactor design created to conform to a policy contrived to assure that nuclear power is not a long-term source of energy and that antinuke activists are apeased.
Are you saying that the Even numbererd trans-uranics can operate in Fast reactors and odd numbererd ones in thermal reactors?
I was thinking that since the long lived trans-uranics present the greatest problem as regards long term waste that a better soultion would be to separate them by reprocessing and use them as fuel (If possible)
I can imagine that not all of them would be suited for MOX type fuel with Urainium but some may be useable in reactors specifically designed to use them. With a small reactor programme we may simply not produce enough of the diferent trans-uranics to justify the construction of special reactors to utilise them but with a Large programme processing large ammounts of material we may be able to do so.
but time is also a factor -- the 70,000 tonnes of used fuel slated to go to Yucca Mtn., accumulated over decades, certainly contains a significant amount of Pu & other transuranics for use in MOX.
Note that MOX merely means "mixed oxides" -- it doesn't say whether its for use in light water or fast reactors.
