tag:blogger.com,1999:blog-7597656451205429515.post1104097770534341967..comments2024-02-16T17:52:44.944-06:00Comments on The Nuclear Green Revolution: The Big Lots Reactor DiscussionsCharles Bartonhttp://www.blogger.com/profile/01125297013064527425noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-7597656451205429515.post-12656450582718427192009-03-25T11:20:00.000-05:002009-03-25T11:20:00.000-05:00Alex P. I have seen it before in the Eft discussio...Alex P. I have seen it before in the Eft discussion form, but unfortunately the form is not searchable by topic.Charles Bartonhttps://www.blogger.com/profile/01125297013064527425noreply@blogger.comtag:blogger.com,1999:blog-7597656451205429515.post-73203405077203145442009-03-25T09:57:00.000-05:002009-03-25T09:57:00.000-05:00By the way, have you got any idea about the fissil...By the way, have you got any idea about the fissile start-up for an epithermal/faster version for example for GWe (of course for a two fluids approach)? There is no mention in the Moir's paperAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7597656451205429515.post-58595523282599870642009-03-25T09:53:00.000-05:002009-03-25T09:53:00.000-05:00Indeed there are some other issues (besides Pu sol...Indeed there are some other issues (besides Pu solubility) with non moderated versions,in particular if we want to load the reactor with LWR transuranics;<BR/>from a Moir's paper :<BR/>http://www.geocities.com/rmoir2003/2mlt_slt.htm<BR/><BR/>"... The reactor design is simplified by removing the graphite<BR/>moderator in the core thus eliminating the graphite<BR/>damage lifetime limitation. The harder neutron spectra<BR/>will reduce actinide captures thus enhancing fissioning of<BR/>transuranics. However, the reflector material inside the<BR/>reactor vessel sees a large neutron flux, and will have to<BR/>be replaced periodically. The reflector protects the vessel<BR/>walls from neutron damage. This radiation damage will<BR/>set the power density and lifetime to replacement similar<BR/>to the graphite-moderated reactor discussed above. Then<BR/>the power and diameter of the vessel can be determined,<BR/>but this topic is beyond the scope of the present paper.<BR/>The material of the reflector might set a limit to the operating temperature. More attention is needed on the problem<BR/>of radiation damage to the walls for the unmoderated<BR/>MSR "Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7597656451205429515.post-18883300183530105292009-03-25T09:46:00.000-05:002009-03-25T09:46:00.000-05:00I'm really honoured for the invitation, but indeed...I'm really honoured for the invitation, but indeed I'd prefer that a REAL nuclear engineer/physicist (not me!)deal with the topic! I don' t know exactly where but for example I remember that David LeBlanc dealt with the question, showing a slight preference for the epithermal/faster version.<BR/><BR/>Maybe I'm going to open a new thread at the EFT forum discussionAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7597656451205429515.post-75592704987878080392009-03-25T07:58:00.001-05:002009-03-25T07:58:00.001-05:00This comment has been removed by the author.Charles Bartonhttps://www.blogger.com/profile/01125297013064527425noreply@blogger.comtag:blogger.com,1999:blog-7597656451205429515.post-27045220250098514032009-03-25T07:58:00.000-05:002009-03-25T07:58:00.000-05:00ALex P, you certainly are invited to give offer a ...ALex P, you certainly are invited to give offer a guest post here. I am tying to stimulate thinking about the LFTR future, which I hope is near at hand. I am not convinced that there will be a large enough amount of fissionable materials to start 10,000 LFTR's by 2050. Granted I have not tested my thinking with an analysis. You could do it too!Charles Bartonhttps://www.blogger.com/profile/01125297013064527425noreply@blogger.comtag:blogger.com,1999:blog-7597656451205429515.post-52657731655636703002009-03-25T07:39:00.000-05:002009-03-25T07:39:00.000-05:00" There is a school of thought that holds that the..." There is a school of thought that holds that the best solution to the moderator problem is to have none. I might find this approach valid if were were going to be dealing with a limited number of reactors. We are not. I calculated the number of 100 MW "Big Lots" Reactors that would be needed to replace fossil fuel powered electrical generators in the United States. My estimate would be in the neighborhood of 10,000. Using a graphite moderated core design means that only about a fifth as much fissionable materials will be needed to start a moderated LFTR as are needed to start an unmoderated LFTR. The problem is one of scalability. We can start 5 times as many graphite moderated LFTRs with a given amount of fissionable material as we can start if the LFTRs are unmoderated "<BR/><BR/>I'm not so convinced that a moderator free version could be a smarter choice,even if we know that a little of graphite is always needed, I see indeed many advantages in it (and very few drawbacks...) : absence of potentially dangerous graphite/liquids (or hydrogen) chemical reactions, higher power density (that means potentially lower costs of construction), no irradiated graphite waste to dispose at the end of the life, higher (even if slight) breeding ratio and transuranics transmutation and - my favorite! - the possibility to use poorer salts, in particular lithium and/or berillyum free salts, which elements are both costly (Li,and potentially rare in the near future),toxic (Be) and produce tritium (even with enriched Li). The only issue I see in moderator free versions is the solubility in the salt, while I'm not really concerned about the higher fissile start-up for faster versions, we are today in the planet really plenty of unburned transuranics to start with<BR/><BR/>[As a humble sugestion, Charles,I think a comparison between them could be an interesting topic for a new post here at Nuclear Green]Anonymousnoreply@blogger.com