Tahle diskuze je skutecne velmi casove narocna, a casu se mi v posledni dobe sutecne nedostava, takze se nebudu moc rozepisovat, ale spise jen uvedu nekolik linku a citatu - bohuzel v anglictine - na podrobnejsi preklady skutecne asi nenajdu cas.
Nejdrive shrnuti z minulych diskuzi: Jak uz jsem uvadel mnohokrat, rozhodne se tesim az jednou fuzni reaktory budou fungovat. Pri pruzkumu argumentu ekologu jsem jim ale v mnohem musel dat zapravdu. Zjednodusene a ve strucnosti hlavnim problemem je obrovske plytvani prostredky na projekt, ktery podle mnohym odborniku, vcetne fyziku samotnych, nema prilis sanci na uspech. Tim neni myslen fuzni reaktor, ale konkretne ITER. Jde o mamuti stavbu, ktera bude mit tezke a dlouhodobe lokalni ekologicke dusledky, spotrebuje obrovske prostredky, a rekordni mnozstvi energie, a bude trvat velmi dlouho, pricemz se stale jedna jen o pokusny reaktor, bez toho, ze by kdy mel produkovat nejakou energii do site.
Ekologove by mnohem radeji videli tok investici do technologii s okamzitym ucinkem (a tvorbu zakonu podporujich takovou cinnost) - a to nejen na vyrobu energie z obnovitelnch zdroju, ale i na snizovani spotreby. Tak napriklad hybridni motory (spalovaci+elektro), ktere budou pravdepodobne hitem pristich par let - po uspechu Toyoty Priuse, pripravuji hybridy i Peugeot, Renault, VW a dalsi automobilky - tak to vlastne neni zadny technologicky zazrak - kdyby byla snaha, motivace ze strany statu a zakonodarcu, tak jsme je tu mohli mit uz nekolik desitek let a usetrit tak neskutecne mnozstvi ropy. To se tyce spousty dalsich technologii - chybi proste finance, motivace a stimulace, a pritom tyto technologie slibuji (na rozdil od ITERu) okamzity efekt, ktery planeta a lidstvo nezbytne potrebuje.
Diskutovali jsme i solarni energii, kde Duro kritizoval jak je draha a neucinna - narazil jsem pri tom na jednu zajimavou technologii, ktera snad ukaze, ze tomu tak byt nemusi a nepotrebuje na to desitky miliard investici:
http://www.nanosolar.com/
Dalsim z jiz diskutovanych problemu je nebezpeci plynouci z radioktivity materialu oblozeni reaktoru, tekavost a nebezpeci uniku radioaktivniho tricia. Co se tyce problemu vnitrniho oblozeni a jeho radioaktivity, pekny a podrobny clanek o tom je zde:
http://www.carolusmagnus.net/papers/200 ... _Rubel.pdf
Toto je clanek, kritizujici vseobecne popisovani fuze, jako cisteho a ekologickeho zpusobu vyroby a zatajovani rizik a problemu, ktere tam pres vsechny vyhody preci jen jsou:
http://www.ejnet.org/rachel/rhwn368.htm
In 1973, 20 years into the nation's fusion energy research program, the American Association for the Advancement of Science (AAAS) raised a series of concerns about fusion energy, [4] concerns that are still valid today. As AAAS said in 1973, "Operation of a fusion reactor would present several major hazards. The hazard of an accident to the magnetic system would be considerable, because the total energy stored in the magnetic field would be... about the energy of an average lightning bolt" [100 billion joules, equivalent to roughly 45 tons of TNT]. An even greater hazard would be a lithium fire, which might release the energy of up to 13,500 tons of TNT. "But the greatest hazard of a fusion reactor... would undoubtedly be the release of tritium, the volatile and radioactive fuel into the environment," the AAAS said. Tritium is radioactive hydrogen gas; it is a tiny atom, very difficult to contain. (It can escape from some metal containers by slipping right through the metal.) Furthermore, tritium is hydrogen, which can become incorporated into water, making the water itself weakly radioactive. Since most living things, including humans, are made mostly of water, radioactive water is hazardous to living things. Tritium has a half-life of 12.4 years, so it remains hazardous for about 125 years after it is created. The AAAS estimated in 1973 that each fusion reactor would release one to 60 Curies of tritium each day of operation through routine leaks, even assuming the best containment systems. An accident, of course, could release much more because at any given moment there would be 100 million Curies of tritium inside the machine, a large inventory indeed.
Co se tyce sanci Tokamackeho typu reaktoru, tak k tomu se nekolik skupin vedcu stavi take velmi skepticky. Jeden z vedcu se o Tokamaku a o principu drzeni plazmy v magnetickem poli vyjadril, ze je to jako by se clovek snazil udrzet ve vzduhu syrovy zloutek pomoci napnutych gumicek. Tady je treba par vet, ktere jsem si kdysi zkpiroval, ale uz si nepamatuju z ktereho clanku jsou:
We don't know enough about plasma containment. Plasmas are hot, high-pressure, nonequilibrium clouds of charged particles. Whenever you try to keep one dense and hot enough to fuse, it develops instabilities and "squirts" out of its magnetic bottle one way or another. Thanks to past plasma research (much of it at Princeton and MIT) we understand most of these, so we've designed ITER to control them and contain the plasma. But we don't understand all the instabilities, so we can't begin to guess power reactor---something 10x as big as ITER---should be designed. ITER itself will teach us how to predict and handle these instabilities.
The inside coating of the reactor will be exposed to more radiation than anything ever seen. In a fission reactor, most of the heat is generated within the uranium rods themselves. It's generated by harmless alpha and beta particles; only a little of the energy emerges as neutrons. Neutrons cause tremendous, complex, and unpredictable damage to materials, even metals. A power-generating fusion plant (on the T-D cycle) will pump a gigawatt worth of neutrons into its "blanket". We have no idea how to build blanket materials that will survive this bombardment. ITER will provide an testbed for materials engineering.
Pritom existuje koncept reaktoru, ktery podle nekterych vedcu ma mnohem vetsi sanci na brzky pokrok. Problem je v tom, ze je to pomerne novy pristup, neni zalozen na 50-letem postupnem vyvoji, jako Tokamak, a hlavne je problem s investicemi. Colliding Beam Fusion Reactor je popsan napriklad zde:
http://www.sciencemag.org/cgi/content/f ... NwOzIwyrKA
Tady je z toho clanku par kritickych vet o tokamackem reaktou ITER:
1) Magnetic confinement in such a reactor is much less effective than expected. The phenomenon of anomalous transport leads to a large minimum size for adequate confinement. This limit implies a minimum plant size of about 10 GW.
2) The deuterium-tritium fuel yields most of its fusion energy in the form of 14-MeV neutrons, which create a great deal of radioactivity. Low-activation materials have been suggested to reduce this problem, but it is not certain that they can be developed with adequate physical properties. In addition, the 14-MeV neutrons cause radiation damage to materials. The neutron flux must be less than about 2 MW m2 for the first wall to have a reasonable lifetime. Then, massive shielding is required to protect the superconducting magnets.
3) The Tokamak is toroidal. Therefore, the construction of the coils, vacuum system, and so forth make maintenance difficult and expensive.
Tady je jiny clanek o tomto alternativnim fuznim reaktoru, ktery by mel mit lepsi vlastnosti a mnohem mene by zatezoval zivotni prostredi
http://today.uci.edu/news/release_detail.asp?key=439
Jen pro zajimavost, tady je clanek o jinem fuznim reaktoru (Focus Fusion), jemuz Bush take utnul financovani:
http://www.focusfusion.org/faq.html
Tady je jedna ze silnejsich kritik Tokamaku ze strany vedcu:
http://susanhu.dailykos.com/story/2005/6/28/12444/9512
I post this as a former fusion researcher and a former project manager for the Office of Fusion Energy (OFE) of the Department of Energy (DOE)
Many decades ago the international fusion community put all of its chips on the Tokamak. It has been a disaster.
Even if a Tokamak could produce break-even fusion ( getting more energy out than you put in) the engineering obstacles to creating an economically successful reactor are daunting.
Many years ago, the OFE sponsored a study, Project Aries, of the costs of a Tokamak reactor. Even using the usual optimistic assumptions, the cost came in way above solar and wind power, let alone fossil fuels.
Another symptom of the problem is that three times in a row, projects to build larger Tokamak have collapsed in the design stage. That is, even before anything was build, none could come up with a working design. The International Thermonuclear Experimental Reactor (ITER), the latest attempt, collapsed as the price tag spiraled above $20 billion, but now is resurrected. I assume that they found some technical advances, or just "cooked the books" space-station style to justify it.
The whole OFE degenerated into a "you scratch my back and I'll scratch yours" process where the lab directories divvied up the pie. All non-Tokamak ideas were cut off, including the one I worked on.( more below).Congress cut the OFE budget almost in half a 10 years ago in response to this.
Now for a blatant plug. In the 70s I worked on a small project at the University of Miami, the Trisops project, which was defunded. The amount of money was not an issues ( our request was quite small), but the non-Tokamak nature, and the nerve of the principal investigator, Dan Wells, to point out that the Tokamac was unworkable.
Last decade the Trisops machine was moved from the University of Miami, to Lanham Md, with a small NASA grant, but there is not money to run it. You can see a report on it.
Another interesting project, the Plasmak(TM) project that is being run by Paul Koloc ( out of his garage!!).
The holy grail on fusion research is a stable plasma structure. The Trisops project achieved it one way. Paul has noted that ball lightning, which has been known for millennia, is a stable plasma structure. He has machine that produces ball lightning, and is measuring it. He gets no DOE funding of course.
A jeste tu mam link na clanek o termalni poluci, ktery ukazuje, dopad nuklearnich zarizeni na ekosystem.
http://www.nuclear.com/n-plants/index-t ... ution.html
Na zaver bych jeste rad rekl, ze prestoze ekologove vetsinou funguji jako brzda pokroku, spolecnost je nutne potrebuje. Nebyt ekologu, kterym se v prubehu druhe pulky posledniho stoleti podarilo prosadit alespon minimalni kontroly a regulace prumyslu i vedy, a hlavne i trochu pozmenit mysleni lidi, asi by ten svet vypadal dnes mnohem hur. Jejich cilem ale neni zamezit pokroku, vede a novym technologiim - cilem je, aby kazdy jedntolivec, firma, nebo instituce meli dopad na ekologii pokud mozno neustale na mysli a svoji cinnost neustale optimalizovali. Jak to s zivotnim prostredim dopada, kdyz nejsou zadne nebo dostatecne natlakove prostredky, jsme bohuzel videli v minulem stoleti a vidime i ted vice nez dost.
