From: everything-list@googlegroups.com [mailto:everything-list@googlegroups.com] On Behalf Of meekerdb Sent: Saturday, April 04, 2015 8:59 PM To: everything-list@googlegroups.com Subject: [SPAM]Re: Fast moves for nuclear development in Siberia On 4/4/2015 7:45 PM, 'Chris de Morsella' via Everything List wrote: Whatever the breeder fuel cycle: LFTR or the (seems like the Russians are going in that direction) plutonium economy; inherent passive safety features are critical. If we learned anything from Fukushima, I would argue that one of the lessons must be that reactors need to be walk away safe, being designed with in-built passive safety designed failure modes. This also argues for smaller scale units than behemoths like the MarkII design. The very big units just generate too much heat all, in a remarkably small place… too much for passive safety to be practical. I think a better reactor scale would be around 200MW, big enough to matter, but small enough to be manageable in failure mode. Most proposed advanced reactors will operate at higher temperatures than the older designs. This both makes them more thermodynamically efficient and it allows them to be air cooled. The safety problem isn't from the high temperature in the design use, it's from the residual radioactive components that continue to decay after the reactor shuts down. There's been assertions about Fukushima's core melt down and escaping the reactor vessel based on muon imaging. But the corium didn't escape the concrete containment under the reactor. It is not so much the operating temperature itself but the continued production of massive amounts of thermal energy (from continued radioactive decay going on inside the core + the SFPs as well) even as the plant is being put into shutdown mode, which is one of the issues with the big PWR type reactors. Even after fission has been halted, it takes weeks for a big PWR to cool down, as the on-going decay produces large amounts of heat. In reference to the recent muon imaging: I don’t think they know that it did not already burn through the outer concrete containment, in fact the muon imaging suggests that it may have in fact already burnt all the way through and be located somewhere in the underlying earth/rock matrix beneath that particular unit. Meltdowns have occurred in units: #1, #2, and #3 – that is three core meltdowns in all. Chris Brent -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
RE: [SPAM]Re: Fast moves for nuclear development in Siberia
'Chris de Morsella' via Everything List Sun, 05 Apr 2015 11:24:59 -0700
