Clean And Environmentally Safe Advanced Reactor
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{| class="infobox" style="width:22em;"
! colspan="2" style="font-size:larger;" | Disputed Science:<br />
CAESAR nuclear reactor
|- style="vertical-align:top;"
| '''Disciplines:'''
|
Nuclear engineering;
Nuclear technology;
Nuclear physics
|- style="vertical-align:top;"
| colspan="2" | '''Core Tenets:'''
|- style="vertical-align:top;"
| colspan="2" |
Self-sustained fissioning of Uranium 238 can be accomplished via steam moderated neutrons
|- style="vertical-align:top;"
| '''Year Proposed:'''
| 1998
|- style="vertical-align:top;"
| '''Original Proponents:'''
|
Dr. Claudio Filippone
|- style="vertical-align:top;"
| '''Current Proponents:'''
|
Dr. Claudio Filippone
|}
The '''Clean And Environmentally Safe Advanced Reactor''' (CAESAR) is a [[nuclear reactor]] concept that uses [[steam]] as a [[neutron moderator|moderator]]. Steam's [[density]] can be controlled very finely so, according to its developer Dr. Claudio Filippone, it can be used to fine tune [[neutron flux]]es to ensure that [[neutron]]s are moving with an optimal neutron energy profile to split [[Uranium-238|<sup>238</sup>U<sub>92</sub>]] nuclei.
The CAESAR reactor design exploits the fact that the [[fission product]]s and [[daughter isotope]]s produced via nuclear reactions also decay to produce additional [[delayed neutron]]s. Dr. Filippone claims that unlike conventional water-cooled fission reactors, where fission occurring in enriched <sup>235</sup>U fuel rods moderated by liquid water coolant ultimately creates a [[Maxwellian]] thermal neutron flux profile, the neutron energy profile from delayed neutrons varies widely. In a conventional reactor, he theorizes, the moderator slows these neutrons down so that they cannot contribute to the <sup>238</sup>U reaction; <sup>238</sup>U has a comparatively large cross-section for neutrons at high energies.
Dr. Filippone maintains that when steam is used as the moderator, the average neutron speed/energy is increased from that of a liquid water moderated reactor and the delayed neutrons keep going until they hit another nucleus. He claims that the resulting extremely high [[neutron economy]] will make it possible to maintain a self-sustaining reaction in fuel rods of pure <sup>238</sup>U, once the reactor has been started by enriched fuel.
Skeptics, however point out that it is generally believed that a controlled, sustained chain reaction is not possible with <sup>238</sup>U. It can undergo fission when impacted by an energetic neutron with over 1 MeV of kinetic energy. But the number of high-energy neutrons produced by <sup>238</sup>U fission are not, themselves, sufficient to induce enough successive fissions in <sup>238</sup>U to create a critical system (one in which the number of neutrons created by fission is equal to the number absorbed). Instead, bombarding <sup>238</sup>U with neutrons below the 1 MeV fission threshold causes it to absorb them without fissioning (becoming <sup>239</sup>U) and decay by [[beta emission]] to <sup>239</sup>Pu (which is itself fissile).
The CAESAR Project is headed by Dr. Filippone, who is a nuclear scientist and the Director of the Center for Advanced Energy Concepts at the [[University of Maryland, College Park]].
==External links==
*[http://www.caesar.umd.edu/ The Clean And Environmentally Safe Advanced Reactor (CAESAR) Project]
*[http://economist.com/science/displayStory.cfm?story_id=1559861 Hail, Caesar] Economist article
*[http://www.popularmechanics.com/science/research/1281696.html Putting Nuclear Waste to Work] Popular Mechanics article from 1998 describing a related reactor design (NPTRE) proposed by Dr. Filippone.
*[http://www.umresearch.umd.edu/newsletter/RFUM030303.htm#5 A Second Caesar to Change the Course of History?] Article from University of Maryland newsletter.
== See also==
* [[Nuclear fission]]
* [[Nuclear reactor]]
* [[Nuclear reactor physics]]
* [[Nuclear power]]
* [[Nuclear power plant]]
* [[Future energy development]]
* [[Energy amplifier]]
* [[Nuclear waste]]
[[Category:Nuclear power reactor types]]
[[Category:Pseudophysics]]