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    DOTCOMJaderna fuze aneb spasa svetove energetiky do 30 let
    DRZEEF
    DRZEEF --- ---
    Collaboration between MIT and a new private company, Commonwealth Fusion Systems

    3Q: Zach Hartwig on MIT's big push on fusion | MIT News
    http://news.mit.edu/2018/3q-zach-hartwig-mit-big-push-fusion-0309

    investments come from Eni, a multinational energy company seeking to diversify its portfolio with a forward-looking investment in fusion energy.

    A new era in fusion research at MIT | MIT News
    http://news.mit.edu/2018/new-era-fusion-research-mit-eni-0309
    DRZEEF
    DRZEEF --- ---
    Is it true that this reactor doesn't use the latest REBCO superconductors? I watched a talk where they claim they can make reactors 10x smaller now, because they increased the strength of the magnetic field (can go up to 10-20T, instead of 3T). And the superconducting tape is cheap, much more flexible and only needs to be cooled to 100K instead of 4K.

    If that's true and I'm not mistaken, the MIT ARC reactor would be much better posed to win the race than Wendelstein 7-X, especially that W7X doesn't aim to generate surplus energy. A commenter above was wondering at the expensive diamond window they had to use. This project is going to be too expensive and with dated technology. We could do it cheaper now.


    ***

    The design for ITER was finalized in 2001, amended in 2007. Construction for W7-X started 2003. W7-X is now built, fully functional and operational. At several points during its construction, the construction process for its required parts had to be invented first.

    That's 15+ years of research, breakthroughs and inventions in plasma confinement physics and engineering that have had to happen first.

    As a noncommercial research reactor, W7-X will continue to be useful for many years to come. For material testing alone I would imagine access to reactor capable of producing a stable, continuous fusion reaction is invaluable.

    The ARC is a design proposal from 2015. As such they have access and can utilize all the achievements, results and processes from W7-X, ITER and other material science advances of the last 15 years. If their proposal was not better than already built specimens, it would be a bad proposal. To declare it a race against the research foundation they built upon seems ignorant at best.

    In 10-20 years, when the ARC is built, a new design proposal will emerge, based on even newer advances in material science and the lessons learned from building the ARC. And it again will be better than the then current, assembled reactors. That is how it is supposed to be.

    ****

    W7X isn't a reactor. It is not even fusion. It's just plasma physics research.

    Is it true that this reactor doesn't use the latest REBCO superconductors? I wat... | Hacker News
    https://news.ycombinator.com/item?id=13150782
    DRZEEF
    DRZEEF --- ---
    DRZEEF
    DRZEEF --- ---
    FYI: mame 45 TESLA high-field na REBCO.... narozdil od ITERU 5 Tesla supravodic z 50.tych let s Niobem

    pres 20 TESLA to ma jiz pres 30 let

    REBCO (REBa2Cu3Ox, where RE = Y, Gd)

    nedostatek chemickych fyziku imo, materialovych chemiku a fyziku se znalosti chemie.... tolik k materialum

    cerven 2019

    45.5-tesla direct-current magnetic field generated with a high-temperature superconducting magnet

    https://www.nature.com/articles/s41586-019-1293-1

    + je to odolne proti Quenchi

    ja to netusil, vsiml jsem si toho dnes nahodou pri cteni supravodicu pri pokojove teplote, high-pressure

    ale je jiste ze to vedouci zodpovedni za ITER totalne podelali

    podivej se na ty kalkulace

    This can be seen by noting that 9.2 T ARC has a fifth of the ∼$24B price of the 5.3 T ITER (calculated by applying the fabricated component scaling to the ∼ 23,000 tonne ITER). Yet ARC matches ITER's fusion power and produces net electricity. The cost of ARC is approximately one-third the cost of the 8 T ARIES-RS (∼$14B), but ARIES-RS has approximately four times the electrical output. The smaller ARC is appropriate for an “entry-level” fusion Pilot plant, but there likely exists a better economic optimization of magnetic field strength versus mass for a full power plant.


    REBCO v ARC vs ITER (niobium-tin (Nb3Sn), "REBCO-free ITER fail")

    A natural comparison is ITER which also produces 500 MW of fusion power with a similar shaping (ϵ ∼ 0.33), but with B0 ∼ 5.3 T. As expected from the dependence in fusion power density, the peak on-coil field of Bcoil,max ∼ 20 T enabled by REBCO technology allows ARC to achieve a FNSF/Pilot-relevant areal fusion power density (∼3 MW/m2) in a device with roughly a tenth of ITER's volume. Additionally, as a consequence of the high toroidal field, the ARC design point has double the safety factor of ITER, making it more robust against disruptions.

    ARC: A compact, high-field, fusion nuclear science facility and demonstration power plant with demountable magnets - ScienceDirect
    ARC: A compact, high-field, fusion nuclear science facility and demonstration power plant with demountable magnets - ScienceDirect
    https://www.sciencedirect.com/science/article/pii/S0920379615302337?via%3Dihub
    DOTCOM
    DOTCOM --- ---
    KAERO: no tenhle argument docela zabira, ale casem se asi ohraje....
    KAERO
    KAERO --- ---
    DOTCOM: tak vzdycky muzes jit za ministrem (evropskym komisarem, sefem akademie, panembohem) a rict mu, hele koukej co delaji cinane, my bychom meli taky
    PETER_PAN
    PETER_PAN --- ---
    DOTCOM: OK .. Ovsem par kilometru od nas, tusim v nejakych Bavorech, tam do toho slapou slusne - lide s timto typem mindsetu.

    IMHO je to krucialne on-topic, resit politickou otazku. Bez politicke podpory nejsou penize ani prestiz. Bez penez nejsou projekty a bez prestize mlada generace co to potahne. Ztrata 1 generace je technologicky i bezpecnostni propad mozna o desitky (?) let? Podobne jako utlum raketove techniky v USA kdyz uz studena valka byla vlazna. Ano vedl ke zkostnateni a pozapomenuti nekterych postupu (zejmena oblast H2 motoru, nejnarocnejsich na implementaci) - jen priklad.
    Stejne takhle to vidi treba nekteri chirurgove, rikaji ze kdyby se ztratila 1 generace v oblasti neurochirurgie, je to propad toho oboru do minuleho stoleti.

    A samozrejmne te politicke podpore predchazi s velkou setrvacnosti nejaka verejna podpora, naladeni verejneho mineni. No a kdyz mas skupinu lidi, tmaru, kteri jsou ochotni pouzivat lzive, zkreslene, prekroucene, vhodnym zpusobem emocionalne zabarvene argumenty aby treba 30 let to verejne minemi menili - pak u projektu ktere jsou na dekady a potrebuji politicke zaruky, tahas za ten kratsi kus provazu.

    Takze popularizace vedy a i suvereni vystoupeni proti takovym zajmovym skupinam by mela byt soucast kazdeho zainteresovaneho akademika.
    DOTCOM
    DOTCOM --- ---
    PETER_PAN: tak to je otazka preferenci, kazdopadne tenhle subjekt ma aktualne ~1% preferenci a pokud vim tak nikdy nezasahl do pristupu k jaderne energetice v tehle zemi (uf :)
    DOTCOM
    DOTCOM --- ---
    KAERO: tvl to me desi ve snu :)
    PETER_PAN
    PETER_PAN --- ---
    DOTCOM: Trochu si rypnu. V tomhle smyslu bych se i zamyslel jaky politicky subjekt jsi v minulosti primo/neprimo (?) podporoval. ;-)
    KAERO
    KAERO --- ---
    DOTCOM: uz se ucis mandarinstinu? :)
    DOTCOM
    DOTCOM --- ---
    CYBERWOLF: bohuzel to tak vypada. Podpora ITERu v USA uz ted rok od roku kolisa, nekolikrat z projektu malem vystoupili. A v Evrope je zase cim dal tezsi prosazovat v Evropskem parlamentu dalsi prostredky na bobtnajici rozpocet. Pokud by ITER nedosahl svych cilu, tak by se toho pravdepodobne chytla antijaderna lobby a byl by to maler
    Jedinej, kdo toho IMHO pujde za kazdyho pocasi je Cina. Takze ja i moji kolegove se modlime abychom se tam jednou nemuseli stehovat :)
    CYBERWOLF
    CYBERWOLF --- ---
    DOTCOM: až tak?
    DOTCOM
    DOTCOM --- ---
    PETER_PAN: no to znamena ze by to vyzadovalo dalsi intenzivni vyzkum jinde nez v mainstreamu (kterej ITER reprezentuje). Na to cisty zisk v elektrine je Q=10 minimum (ucinnost konverze elektrina -> ohrev plazmatu je ~1/3 a konverze teplo -> elektrina taky ~1/3)
    PETER_PAN
    PETER_PAN --- ---
    DOTCOM: Tzn. ze treba pri Q=5 je nerealne myslet na ekonomicky pouzitelnou elektrarnu?
    DOTCOM
    DOTCOM --- ---
    PETER_PAN: mno ja bych rekl ze ITER dosahne Q=10+-5. To asi vyjadruje duveryhodnost tech skalovani :) pokud ale dosahne Q < 10, tak bude asi minimalne v Evrope a USA s fuznim vyzkumem amen.
    PETER_PAN
    PETER_PAN --- ---
    DOTCOM: OK, diky. Tak jestli je predpoklad ze u ITERu to bude 10, tak to musi byt hodne tvrde teoreticke argumenty, ze? Vlastne musely byt, protoze to byl patrne jeden z dulezitych podkladu proto aby se projekt ITER rozjel a nasypali se tam penize.

    Jak rikam, jako naprosty laik jsem velmi prekvapen ze se od toho roku 1958 nepodarilo vic.
    DOTCOM
    DOTCOM --- ---
    PETER_PAN: tak to je Q=0.6 na JETu. Pristi rok to chteji zopakovat :)
    DOTCOM
    DOTCOM --- ---
    PETER_PAN: vyzkum fuze je dost komplikovanejsi nez ze bychom porad jen zkouseli jestli nam ve vyboji padne vyssi Q. Existuje spousta mensich zarizeni (treba nas COMPASS), kterej Q vubec neresi, ale zameruje se treba na to, jaky bude rozlozeni tepelnych toku na stene komory, jak je to s prechodem do modu vyssiho udrzeni atd.
    Z hlediska tech pokusu o dosazeni Q na JETu a JT-60 je spis dulezite, jestli je dane zarizeni schopne dosahnout hodnot, ktere predpovidaji semi-empiricke modely nebo simulace.
    PETER_PAN
    PETER_PAN --- ---
    KAERO: OK, tohle uznavam. Me zajima tedy soucasna nejvyssi experimentalne dosazena hodnota pro D-T fuzi v Tokamaku/Stellaratoru. Ne extrapolovana, ne odhadovana. Soucasna dosazena pro samotnou fuzi. Tj. Ohrev plasmatu vysokou frekvenci vs. energeticky zisk v ramci fuze. To ze neco stoji rezie kolem, chlazeni neni ted dulezite (jedna se o experimenty ne o vyladeny provoz). Zajima me energeticky zisk fuze.
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