tag:blogger.com,1999:blog-7597656451205429515.post5330667246533664678..comments2024-02-16T17:52:44.944-06:00Comments on The Nuclear Green Revolution: Does Nuclear Grade Graphite Burn?Charles Bartonhttp://www.blogger.com/profile/01125297013064527425noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-7597656451205429515.post-1027986827397459102011-04-09T23:48:14.807-05:002011-04-09T23:48:14.807-05:00just another misleading claim from the nuclear ind...just another misleading claim from the nuclear industry, along the lines of "too cheap to meter". <br />I love it when the antis try to trot this out as some kind of trump card. This phrase was used once by former AEC Chairman Lewis Strauss in 1954, referring to Project Sherwood, a secret program to develop power from hydrogen fusion, not uranium fission reactors as is commonly believed, and as discussed in this article.<br /><br />It would be less disingenuous to point to renewables advocates constantly reminding us that the sun and wind are “free”. Just another misleading claim by the antis.Atomikrabbithttps://www.blogger.com/profile/02378221046939835905noreply@blogger.comtag:blogger.com,1999:blog-7597656451205429515.post-3904160192878980802011-04-02T16:55:24.190-05:002011-04-02T16:55:24.190-05:00I note and appreciate your position, but to my min...I note and appreciate your position, but to my mind, it isn't clear that graphite fires are not serious hazards and won't be until we've run we have built some PBRs and seen how they perform over decades. Graphite appears to be pretty stable under the conditions that we think PBRs will produce, both when they are working properly and when they fail, provided that they fail in ways that we expect. However, that's not a terribly high standard, when set against the consequences of misunderstanding how reactors can go wrong.Jez Westonnoreply@blogger.comtag:blogger.com,1999:blog-7597656451205429515.post-35378340188972594962011-04-02T16:00:42.763-05:002011-04-02T16:00:42.763-05:00Joe, I have not taken a position that Graphite doe...Joe, I have not taken a position that Graphite does not burn, but it is clear that graphite fires are not serious hazards to PBMRs. General Atomic used demonstrations in which its represenatives deliberately attempted to start fires in blocks of nuclear grade graphite, as described.Charles Bartonhttps://www.blogger.com/profile/01125297013064527425noreply@blogger.comtag:blogger.com,1999:blog-7597656451205429515.post-68123852424408805362011-04-02T15:21:54.540-05:002011-04-02T15:21:54.540-05:00Graphite does burn. We know it burns because a gra...Graphite does burn. We know it burns because a graphite fire burned for six days at Chernobyl.<br /><br />The OECD's <a href="http://www.oecd-nea.org/rp/chernobyl/c01.html" rel="nofollow">Nuclear Energy Agency report on Chernobyl</a> describes the difficulty of fighting that graphite fire when faced with the worry of either releasing more radionuclides or triggering another criticality. <br /><br />So I'm curious to know how General Atomics justify their claim that it is "virtually impossible" for reactor-grade graphite to burn, because "virtually impossible" looks like just another misleading claim from the nuclear industry, along the lines of "too cheap to meter".Jez Westonnoreply@blogger.comtag:blogger.com,1999:blog-7597656451205429515.post-49970626075849012542011-03-31T07:50:40.623-05:002011-03-31T07:50:40.623-05:00Back when studying me and a friend ask ourself thi...Back when studying me and a friend ask ourself this question after reading GA's claim. So we went over to the head of the hot lab at the university and asked him if he as a piece of reactor grade graphite to borrow us. Turns out he had.<br /><br />So we put to the test, here are the video of it.<br /><br />http://www.youtube.com/watch?v=PqmuVaHpw-Y<br /><br />http://www.youtube.com/watch?v=22aTqTKRPBI<br /><br />http://www.youtube.com/watch?v=QxmNqsGhNhY<br /><br /><br />I think the steam + graphite hydrogen producing reaction is to blame in chernobyl.Johanhttps://www.blogger.com/profile/05498292809069746898noreply@blogger.comtag:blogger.com,1999:blog-7597656451205429515.post-11509703783030479252011-03-31T07:34:50.183-05:002011-03-31T07:34:50.183-05:00Burning nuclear grade high density graphite is sur...Burning nuclear grade high density graphite is surprisingly hard. Set a blowtorch to it and it won't do much at all, tiny amount will oxidise, barely measurable, and then it won't do anything anymore.<br /><br />The 400 Celcius figure is wrong, in order to burn nuclear graphite you need more like 4000 Celcius!!! At those extreme temperatures graphite can burn, carbon is a gas (yes a GAS) at those temperatures. However those temperatures will not ever be achieved in reactors with negative power/temperature and void coefficients. Decay heat is never enough to get 4000 Celcius.<br /><br />In order to burn graphite at lower temperatures, one needs to add a strong oxidiser such as nitrate or water. This then makes carbon monoxide gas which can burn.<br /><br />In Chernobyl, what happened was there was a reactor that wanted to blow itself up because it had positive feedback power coefficients. When an experiment was done with the reactor it did exactly that. There was also no full containment, rather a typical industrial building with some slight pressure control (!).<br /><br />Result was 10000% power which vaporized the reactor core and temperatures plus water from the coolant that was already in and near the core plus water from the environment were present that could combust graphite.<br /><br />A molten salt reactor operates at low pressure and no driving force to breach containment, so no possibility of water going in, and has negative power coefficients. Indeed the boiling point of the salt is well below the ignition temperature of graphite; hence the salt would sooner boil away even if cooling failed and the graphite would be spared higher temperatures while the salt would condense on the passively cooled containment. A big mess inside the reactor but no release of radioactivity to the environment and moreover simple normal operating passive cooling will be used to prevent this event.Cyril Rhttps://www.blogger.com/profile/17667288494374310919noreply@blogger.com