Lub fusion reactor yog qhov tseem ceeb ntawm lub raj mis hlau nplaum uas muaj cov txheej txheem tib yam uas tshwm sim hauv lub hnub. Deuterium thiab tritium fuels fuse los ua ib qho vapor ntawm helium ions, neutrons thiab cua sov. Raws li qhov kub no, ionized roj-hu ua plasma-kub, qhov cua sov tau hloov mus rau dej los ua kom muaj zog tig turbines uas tsim hluav taws xob. Lub plasma superheated ua rau muaj kev hem thawj rau lub reactor phab ntsa thiab lub divertor (uas tshem tawm cov khib nyiab los ntawm kev ua haujlwm reactor kom cov plasma kub txaus kom hlawv).

"Peb tab tom sim txiav txim siab tus cwj pwm tseem ceeb ntawm cov khoom siv plasma nrog lub hom phiaj ntawm kev nkag siab zoo dua cov txheej txheem degradation yog li peb tuaj yeem tsim cov khoom muaj zog, cov ntaub ntawv tshiab," hais tias cov ntaub ntawv kws tshawb fawb Chad Parish ntawm Lub Tsev Haujlwm Saib Xyuas Lub Zog Oak Ridge National Laboratory. Nws yog tus kws sau ntawv qib siab ntawm kev kawm hauv phau ntawv xov xwmKev Tshaj Tawm Txog Kev Tshawb Fawbuas tshawb nrhiav degradation ntawm tungsten nyob rau hauv reactor-tseem ceeb tej yam kev mob.

Vim tias tungsten muaj qhov siab tshaj plaws melting point ntawm tag nrho cov hlau, nws yog ib tug neeg sib tw rau plasma-facing cov ntaub ntawv. Raws li nws cov brittleness, txawm li cas los xij, kev lag luam fais fab nroj tsuag yuav zoo dua yog ua los ntawm tungsten alloy lossis composite. Txawm li cas los xij, kev kawm txog yuav ua li cas lub zog atomic bombardment cuam tshuam rau tungsten microscopically pab engineers txhim kho cov ntaub ntawv nuclear.

"Nyob rau hauv lub fusion fais fab nroj tsuag yog qhov phem tshaj plaws ib puag ncig engineers puas tau raug hais kom tsim cov ntaub ntawv rau," Parish hais. "Nws yog qhov phem dua li sab hauv ntawm lub tshuab dav hlau."

Cov kws tshawb fawb tab tom kawm txog kev sib cuam tshuam ntawm cov ntshav plasma thiab cov khoom siv tshuab los ua cov ntaub ntawv uas muaj ntau tshaj qhov sib tw rau cov kev ua haujlwm hnyav. Kev ntseeg ntawm cov khoom siv yog qhov teeb meem tseem ceeb nrog cov thev naus laus zis tam sim no thiab tshiab nuclear uas muaj kev cuam tshuam loj rau kev tsim kho thiab kev ua haujlwm ntawm cov chaw tsim hluav taws xob. Yog li nws yog ib qho tseem ceeb rau engineer cov ntaub ntawv rau hardiness nyob ntev lifecycles.

Rau txoj kev tshawb fawb tam sim no, cov kws tshawb fawb ntawm University of California, San Diego, tau foob pob tungsten nrog helium plasma ntawm lub zog qis uas ua rau fusion reactor nyob rau hauv ib txwm muaj. Lub caij no, cov kws tshawb fawb ntawm ORNL tau siv Multicharged Ion Research Facility los tua tungsten nrog lub zog siab helium ions emulating tsis tshua muaj xwm txheej, xws li cov ntshav plasma cuam tshuam uas yuav tso lub zog loj heev.

Siv kev xa xov hluav taws xob microscopy, scanning kis electron microscopy, scanning electron microscopy thiab electron nanocrystallography, cov kws tshawb fawb pom cov evolution ntawm npuas hauv tungsten siv lead ua thiab cov duab thiab kev loj hlob ntawm cov qauv hu ua "tendrils" nyob rau hauv qis- thiab siab-zog tej yam kev mob. Lawv xa cov qauv mus rau ib lub tuam txhab hu ua AppFive rau precession electron diffraction, ib tug advanced electron crystallography txheej txheem, infer kev loj hlob mechanisms nyob rau hauv txawv tej yam kev mob.

Tau ob peb xyoos cov kws tshawb fawb tau paub tias tungsten teb rau cov ntshav los ntawm kev tsim cov crystalline tendrils ntawm qhov ntsuas ntawm billions ntawm ib lub 'meter', los yog nanometers - cov nyom me me. Txoj kev tshawb fawb tam sim no tau pom tias cov tendrils uas tsim los ntawm kev foob pob hluav taws xob qis tau qeeb qeeb-loj hlob, zoo dua thiab smoother-ua rau cov ntaub pua plag denser ntawm fuzz-tshaj li cov tsim los ntawm kev quab yuam siab dua.

Hauv cov hlau, atoms xav tias muaj kev sib koom ua ke nrog cov chaw sib txawv ntawm lawv. Yog hais tias ib qho atom raug tshem tawm, qhov chaw khoob, lossis "tawm", tseem nyob. Yog tias hluav taws xob, zoo li lub pob billiard, tsoo lub atom tawm ntawm nws qhov chaw thiab tawm ntawm qhov chaw, lub atom yuav tsum mus rau qhov chaw. Nws crams nws tus kheej ntawm lwm cov atoms nyob rau hauv lub siv lead ua, ua ib qho interstitial.

Ib txwm ua haujlwm fusion-reactor nthuav tawm lub divertor mus rau lub siab flux ntawm lub zog qis-helium atoms. "Ib lub helium ion tsis yog hnyav txaus los ua lub pob billiard sib tsoo, yog li nws yuav tsum tau nkag mus rau hauv lub lattice kom pib ua npuas lossis lwm yam tsis xws luag," Parish piav qhia.

Cov kws tshawb fawb zoo li Brian Wirth, UT-ORNL Tus Thawj Kav Tebchaws Lub Rooj Sib Tham, tau ua qauv ntawm cov txheej txheem thiab ntseeg tias cov khoom uas tau tsiv tawm ntawm lub lattice thaum npuas tsim los ua lub tsev blocks ntawm tendrils. Helium atoms mus ncig ntawm lub lattice randomly, Parish hais. Lawv tsoo rau hauv lwm cov heliums thiab koom nrog rog. Thaum kawg cov pawg loj txaus los khob lub tungsten atom tawm ntawm nws qhov chaw.

"Txhua zaus cov npuas loj hlob nws thawb ob peb tungsten atoms ntau dua ntawm lawv qhov chaw, thiab lawv yuav tsum mus rau qhov chaw. Lawv yuav raug nyiam mus rau saum npoo, "Parish hais. "Qhov ntawd, peb ntseeg, yog cov txheej txheem uas qhov no nanofuzz ​​tsim."

Cov kws tshawb fawb suav ua haujlwm simulation ntawm supercomputers los kawm cov ntaub ntawv ntawm lawv qib atomic, lossis nanometer loj thiab nanosecond time scales. Cov kws ua haujlwm tshawb nrhiav seb cov ntaub ntawv embrittle, tawg, thiab lwm yam coj tus cwj pwm tom qab raug cov ntshav ntev ntev, ntawm centimeter ntev thiab teev sijhawm teev. "Tab sis tsis muaj kev tshawb fawb me me nyob nruab nrab," hais tias Parish, uas nws qhov kev sim ua tiav qhov kev paub dhau los los kawm thawj cov cim qhia ntawm cov khoom siv degradation thiab cov theem pib ntawm kev loj hlob nanotendril.

Yog li ntawd fuzz zoo los phem? "Fuzz zoo li yuav muaj kev puas tsuaj thiab muaj txiaj ntsig zoo, tab sis txog thaum peb paub ntau ntxiv txog nws, peb tsis tuaj yeem tsim cov khoom siv los sim tshem tawm qhov phem thaum hais txog qhov zoo," Parish hais. Ntawm qhov ntxiv, fuzzy tungsten yuav siv cov khoom kub uas yuav tawg ntau tungsten, thiab yaig yog 10 npaug tsawg dua hauv fuzzy dua li cov tungsten ntau. Nyob rau sab minus, nanotendrils tuaj yeem tawg tawm, tsim cov plua plav uas tuaj yeem ua kom cov ntshav txias. Cov kws tshawb fawb lub hom phiaj tom ntej yog kawm seb cov khoom siv hloov pauv li cas thiab nws yooj yim npaum li cas los rhuav tshem cov nanotendrils deb ntawm qhov chaw.

Cov koom tes ORNL tau tshaj tawm tsis ntev los no scanning electron microscopy thwmsim uas teeb pom kev tungsten tus cwj pwm. Ib txoj kev tshawb fawb pom tias kev loj hlob ntawm tendril tsis tau mus rau hauv ib qho kev nyiam nyiam. Lwm qhov kev tshawb nrhiav tau qhia tias cov lus teb ntawm plasma-facing tungsten rau helium atom flux hloov zuj zus los ntawm nanofuzz ​​nkaus xwb (ntawm qis flux) rau nanofuzz ​​ntxiv rau npuas (ntawm siab flux).

Lub npe ntawm daim ntawv tam sim no yog "Morphologies ntawm tungsten nanotendrils zus nyob rau hauv helium raug."