Friday, September 11, 2015

On The TAP Conversion Ratio

The conversion ratio ratio of the Transatomic Power Reactor (TAP Reactor).  Using moderated Plutonium and U-235 fuel, Transatomic believes that they can reach a neer breeder fuel conversion ratio, without using thorium.  The trick relies on using  U-238  to Pu-239 in a moderated reactor.  I will point to evidence that others are probably using similar tricks.

In Addendum B of the TAP White Paper, (Addendum B), Massie and Dewan explaun ahow their moderated reactor, can convert U-238 into Pu-239 at a near 1 to 1 ration, meaning that almost all of their nuclear fuel would be produced within the reactors core, while as little as two percent of the fuel has to be added to keep the chain reaction going at a constant rate.  The tricl is to use a Zirconium Hydride moderator in the center of the core, to promote criticality in that part of the reactor.  Some, but not all neutrons produced by U-235 and Pu-239 fission in the moderated core, will be slowed enough by by the moderator to promote an efficient chain reaction even with very low ratios of fissionable isotopes to U-238.  The moderated area of core is surrounded by an unmoderated pool made up of the same mix or fuel and other actinides floride salts mixed with the carrier coolant salt.  In the case of the TAP reactor the Carrier salt is LiF, which can doo heavy lifting or Uranium Flouride salts.

Neutrons that are slowed down by the moderator ptomote the chain reaction, while neutrons that miss encountering moderator atoms, escape into the unmoderated Actinide salts pool, where most of them get gobbled up by U-238 atoms, that are very good at capturing fast neutrons.  The extra neutron in rthe U-239 atom triggers a nuclear process that leads to a conversion to Pu-239, which is, of course a nuclear fuel.  What mark Massie is claiming here is that with the use of a zarcinium Hydride moderatir, and a clever core design he can produce nuclear fuel at an almost breder range, while keeping the advantages of a moderated reactor.  This is some trick indeed, though I suspect that Massie is not the only one to discover it.  David LeBlank also has claimed a very high breeding ratio from his moderated IMSR design.  I could not understand how he did this, and David has kept his cards close to his chest, but David talked about a 1 1/2 fluid core design, and in a way this is what Massie and Dewan have accomolished, but witout a barier between the fissioning core and the breeding blanket.  This by itself promotes Mark Massie, to the top ranks of 21st century reactor designers, even if his moderator does not work as advertised.  I also suspect that David LeBlank is familure with the same trick, and uses it in the IMSR but not quite with the same conversion efficiency that Mark Massie claims.  The difference between David and Mark is that David plays things very safe by using Graphite moderator, while mark is taking a risk that he can make a Zircinium Hydride moderator work.    If it does more power too him.

No comments:


Blog Archive

Some neat videos

Nuclear Advocacy Webring
Ring Owner: Nuclear is Our Future Site: Nuclear is Our Future
Free Site Ring from Bravenet Free Site Ring from Bravenet Free Site Ring from Bravenet Free Site Ring from Bravenet Free Site Ring from Bravenet
Get Your Free Web Ring
Dr. Joe Bonometti speaking on thorium/LFTR technology at Georgia Tech David LeBlanc on LFTR/MSR technology Robert Hargraves on AIM High