Txoj kev xav ntawm kev sib txheeb hais tias huab hwm coj yog ib hom tshwj xeeb ntawm lub zog. Nws ua raws li nws muaj peev xwm hloov huab hwm coj mus rau hauv lub zog thiab lub zog rau hauv huab hwm coj. Nyob rau theem intraatomic, cov tshuaj tiv thaiv no tshwm sim. Hauv particular, qee qhov loj ntawm lub atomic nucleus nws tus kheej yuav zoo tig mus rau hauv lub zog. Qhov no tshwm sim nyob rau hauv ntau txoj kev. Ua ntej, lub nucleus tuaj yeem lwj mus rau hauv ntau lub nuclei me, qhov tshuaj tiv thaiv no hu ua "kev lwj". Qhov thib ob, cov nuclei me me tuaj yeem sib xyaw ua ke kom muaj qhov loj dua - qhov no yog cov tshuaj tiv thaiv fusion. Nyob rau hauv lub qab ntuj khwb, xws li kev tshwm sim muaj ntau heev. Suffice nws hais tias cov tshuaj tiv thaiv fusion yog lub hauv paus ntawm lub zog rau cov hnub qub. Tab sis cov tshuaj tiv thaiv lwj yog siv los ntawm noob neej hauv nuclear reactors, txij li tib neeg tau kawm los tswj cov txheej txheem nyuaj no. Tab sis dab tsi yog qhov kev tawm tsam nuclear? Yuav tswj nws li cas?
Yuav ua li cas hauv lub nucleus ntawm lub atom
Ib qho tshuaj tiv thaiv kab mob sib kis yog cov txheej txheem uas tshwm sim thaum cov khoom nruab nrab lossis cov nuclei tsoo nrog lwm cov nuclei. Vim li cas "chain"? Qhov no yog ib txheej ntawm kev ua tiav ib qho kev tawm tsam nuclear. Raws li qhov tshwm sim ntawm cov txheej txheem no, kev hloov pauv hauv lub xeev quantum thiab nucleon muaj pes tsawg leeg ntawm thawj nucleus tshwm sim, txawm tias cov khoom tshiab tshwm sim - cov khoom siv tshuaj tiv thaiv. Cov tshuaj tiv thaiv kab mob nuclear, uas nws lub cev tso cai rau ib tus los kawm txog cov txheej txheem ntawm kev sib cuam tshuam ntawm nuclei nrog nuclei thiab nrog cov khoom, yog txoj hauv kev tseem ceeb kom tau txais cov ntsiab lus tshiab thiab isotopes. Yuav kom nkag siab txog qhov ntws ntawm cov tshuaj tiv thaiv kab mob, ib tus yuav tsum ua ntej nrog ib leeg.
Yuav ua li cas rau cov tshuaj tiv thaiv
Yuav kom ua tiav cov txheej txheem xws li cov tshuaj tiv thaiv kab mob nuclear, nws yog ib qho tsim nyog yuav tsum coj cov khoom (lub nucleus thiab nucleon, ob lub nuclei) los ze zog ua ke ntawm qhov deb ntawm qhov sib cuam tshuam muaj zog (txog ib lub fermi). Yog tias qhov kev ncua deb loj, ces kev sib cuam tshuam ntawm cov khoom siv hluav taws xob yuav yog Coulomb nkaus xwb. Hauv cov tshuaj tiv thaiv nuclear, txhua txoj cai raug pom zoo: kev txuag hluav taws xob, lub zog, lub zog, lub zog baryon. Cov tshuaj tiv thaiv kab mob nuclear yog qhia los ntawm lub cim teeb a, b, c, d. Lub cim ib qhia txog tus thawj nucleus, b cov khoom tuaj, c cov khoom tawm tshiab, thiab d cov nucleus tshwm sim.
Reaction zog
Cov tshuaj tiv thaiv kab mob sib kis tuaj yeem tshwm sim ob qho tib si nrog kev nqus thiab nrog kev tso tawm ntawm lub zog, uas yog sib npaug ntawm qhov sib txawv ntawm qhov sib txawv ntawm cov khoom tom qab cov tshuaj tiv thaiv thiab ua ntej nws. Lub zog absorbed txiav txim qhov tsawg kawg nkaus kinetic zog ntawm kev sib tsoo,lub npe hu ua qhov pib ntawm cov tshuaj tiv thaiv nuclear, uas nws tuaj yeem ua tau dawb do. Qhov chaw pib no nyob ntawm seb cov khoom siv hauv kev sib cuam tshuam thiab ntawm lawv cov yam ntxwv. Thaum pib, tag nrho cov khoom yog nyob rau hauv lub xeev quantum predetermined.
Reaction implementation
Lub hauv paus tseem ceeb ntawm cov khoom siv hluav taws xob uas foob pob hluav taws xob yog cov khoom siv hluav taws xob, uas tsim cov kab hluav taws xob ntawm cov protons, hnyav ions thiab lub teeb nuclei. Cov neutrons qeeb tau txais los ntawm kev siv cov tshuab hluav taws xob nuclear. Txhawm rau kho qhov xwm txheej raug them, ntau hom kev tawm tsam nuclear, ob qho tib si fusion thiab lwj, tuaj yeem siv. Lawv qhov tshwm sim yog nyob ntawm qhov tsis sib xws ntawm cov khoom sib tsoo. Qhov no tshwm sim yog txuam nrog xws li ib tug yam ntxwv raws li cov tshuaj tiv thaiv cross section - tus nqi ntawm qhov zoo cheeb tsam, uas characterizes lub nucleus raws li lub hom phiaj rau xwm txheej hais thiab uas yog ib tug ntsuas ntawm qhov tshwm sim hais tias cov particle thiab lub nucleus yuav nkag mus rau hauv kev sib cuam tshuam. Yog hais tias cov khoom uas tsis muaj xoom xaim tuaj yeem koom nrog hauv cov tshuaj tiv thaiv, ces tus ntoo khaub lig seem ncaj qha nyob ntawm lawv txoj kev taw qhia. Txij li thaum lub spines ntawm qhov xwm txheej hais tsis yog kiag li randomly oriented, tab sis ntau los yog tsawg txiav txim, tag nrho cov corpuscles yuav polarized. Cov yam ntxwv ntau ntawm cov nqaj taw qhia tau piav qhia los ntawm polarization vector.
Reaction mechanism
Dab tsi yog cov tshuaj tiv thaiv kab mob nuclear? Raws li twb tau hais lawm, qhov no yog ib ntu ntawm cov tshuaj tiv thaiv yooj yim dua. Cov yam ntxwv ntawm qhov xwm txheej particle thiab nws cov kev cuam tshuam nrog lub nucleus nyob ntawm qhov loj, nqi,kinetic zog. Kev sib cuam tshuam yog txiav txim siab los ntawm qib ntawm kev ywj pheej ntawm cov nuclei, uas zoo siab thaum sib tsoo. Tau txais kev tswj hwm ntawm tag nrho cov txheej txheem no tso cai rau cov txheej txheem xws li kev tswj hwm cov saw hlau tiv thaiv.
kev tawm tsam ncaj nraim
Yog hais tias tus nqi them uas tsoo lub hom phiaj nucleus tsuas yog kov nws, ces lub sijhawm ntawm kev sib tsoo yuav sib npaug rau qhov kev ncua deb uas yuav tsum tau kov yeej qhov kev ncua deb ntawm lub nucleus radius. Xws li cov tshuaj tiv thaiv nuclear hu ua cov tshuaj tiv thaiv ncaj qha. Ib tus cwj pwm zoo rau txhua qhov kev cuam tshuam ntawm hom no yog qhov excitation ntawm tsawg tus lej ntawm kev ywj pheej. Nyob rau hauv xws li ib tug txheej txheem, tom qab thawj kev sib tsoo, lub particle tseem muaj txaus lub zog los mus kov yeej lub nuclear attraction. Piv txwv li, xws li kev sib cuam tshuam xws li inelastic scattering ntawm neutrons, nqi pauv, thiab xa mus ncaj qha. Kev koom tes ntawm cov txheej txheem zoo li no rau tus yam ntxwv hu ua "tag nrho hla ntu" yog qhov tsis txaus ntseeg. Txawm li cas los xij, kev faib khoom ntawm qhov kev nkag mus ntawm cov tshuaj tiv thaiv nuclear ncaj qha ua rau nws tuaj yeem txiav txim siab qhov tshwm sim ntawm kev khiav tawm ntawm lub kaum sab xis ntawm lub nqaj, quantum tooj, kev xaiv ntawm cov neeg nyob hauv xeev, thiab txiav txim siab lawv cov qauv.
Pre-equilibrium emission
Yog tias cov khoom tsis tawm hauv thaj av ntawm kev sib cuam tshuam nuclear tom qab thawj qhov kev sib tsoo, ces nws yuav koom nrog tag nrho cov kev sib tsoo ntawm kev sib tsoo. Qhov no yog qhov tseeb tsuas yog qhov hu ua nuclear chain reaction. Raws li qhov tshwm sim ntawm qhov teeb meem no, lub zog kinetic ntawm cov particle yog faib rauconstituent qhov chaw ntawm lub nucleus. Lub xeev ntawm nucleus nws tus kheej yuav maj mam ua ntau nyuaj. Thaum lub sij hawm tus txheej txheem no, ib tug tej nucleon los yog tag nrho pawg (ib pawg ntawm nucleons) muaj peev xwm mloog zoo zog txaus rau lub emission ntawm no nucleon los ntawm lub nucleus. Kev so ntxiv yuav ua rau muaj kev sib npaug ntawm cov lej thiab tsim cov nucleus.
Chain reactions
Dab tsi yog cov tshuaj tiv thaiv kab mob nuclear? Qhov no yog qhov sib lawv liag ntawm nws qhov chaw. Ntawd yog, ntau qhov kev ua tiav ib zaug ib zaug nuclear tshwm sim los ntawm cov khoom siv hluav taws xob tshwm sim raws li cov khoom siv tshuaj tiv thaiv hauv cov kauj ruam dhau los. Dab tsi yog qhov kev tawm tsam ntawm cov saw hlau nuclear? Piv txwv li, lub fission ntawm hnyav nuclei, thaum muaj ntau yam fission tshwm sim yog pib los ntawm neutrons tau thaum yav tas los decays.
Txoj kev ntawm cov tshuaj tiv thaiv kab mob nuclear
Ntawm txhua qhov tshuaj tiv thaiv, cov tshuaj tiv thaiv kab mob tau siv dav. Cov khoom uas tsis siv cov ntawv cog lus ua lub luag haujlwm ntawm cov dawb atoms lossis radicals. Hauv cov txheej txheem xws li cov tshuaj tiv thaiv kab mob nuclear, cov txheej txheem ntawm nws qhov tshwm sim yog muab los ntawm cov neutrons, uas tsis muaj Coulomb barrier thiab excite lub nucleus thaum nqus. Yog hais tias qhov tsim nyog particle tshwm nyob rau hauv nruab nrab, ces nws yuav ua rau ib tug saw ntawm tom ntej transformations uas yuav mus txuas ntxiv mus txog rau thaum lub saw tawg vim poob ntawm cov cab kuj particle.
Vim li cas tus cab kuj poob
Tsuas yog ob qho laj thawj rau qhov poob ntawm cov khoom thauj khoom ntawm cov saw txuas txuas ntxiv ntawm cov tshuaj tiv thaiv. Thawj yog qhov nqus ntawm cov khoom tsis muaj txheej txheem ntawm emissiontheem nrab. Qhov thib ob yog qhov tawm ntawm cov khoom tawm dhau qhov txwv ntawm qhov ntim ntawm cov khoom uas txhawb nqa cov txheej txheem saw.
Ob hom txheej txheem
Yog tias tsuas yog ib tus neeg nqa khoom me me tau yug los hauv txhua lub sijhawm ntawm cov tshuaj tiv thaiv kab mob, ces cov txheej txheem no tuaj yeem hu ua unbranched. Nws tsis tuaj yeem ua rau kev tso tawm ntawm lub zog ntawm qhov loj. Yog hais tias muaj ntau cov cab kuj, ces qhov no yog hu ua ib tug branched tshuaj tiv thaiv. Yuav ua li cas yog ib tug nuclear saw cov tshuaj tiv thaiv nrog branching? Ib qho ntawm cov khoom thib ob uas tau txais hauv txoj cai dhau los yuav txuas ntxiv cov saw hlau pib ua ntej, thaum lwm tus yuav tsim cov kev cuam tshuam tshiab uas tseem yuav ceg. Cov txheej txheem no yuav sib tw nrog cov txheej txheem ua rau tawg. Qhov teeb meem tshwm sim yuav ua rau muaj qhov tseem ceeb thiab txwv qhov tshwm sim. Piv txwv li, yog tias muaj kev tawg ntau dua li cov saw hlau tshiab, ces kev txhawb nqa tus kheej ntawm cov tshuaj tiv thaiv yuav ua tsis tau. Txawm hais tias nws zoo siab los ntawm kev qhia txog qhov xav tau ntawm cov khoom siv rau hauv ib qho nruab nrab, cov txheej txheem tseem yuav lwj nrog lub sijhawm (feem ntau sai sai). Yog hais tias tus xov tooj ntawm cov chains tshiab tshaj li tus naj npawb ntawm so, ces ib tug nuclear saw cov tshuaj tiv thaiv yuav pib kis thoob plaws hauv cov khoom.
mob hnyav
Lub xeev tseem ceeb cais thaj chaw ntawm lub xeev teeb meem nrog kev tsim kho tus kheej txhawb nqa cov tshuaj tiv thaiv, thiab thaj chaw uas qhov kev tawm tsam no tsis tuaj yeem ua txhua yam. Qhov kev ntsuas no yog tus cwj pwm los ntawm kev sib npaug ntawm cov xov tooj ntawm cov circuits tshiab thiab cov naj npawb ntawm qhov ua tau tawg. Zoo li lub xub ntiag ntawm cov khoom thauj pub dawb, qhov tseem ceeblub xeev yog cov khoom tseem ceeb hauv cov npe xws li "cov xwm txheej rau kev ua raws li cov kev sib txuas lus nuclear." Kev ua tiav ntawm lub xeev no tuaj yeem txiav txim siab los ntawm ntau yam ua tau. Lub fission ntawm nucleus ntawm ib lub caij hnyav yog txaus siab los ntawm ib qho neutron xwb. Raws li qhov tshwm sim ntawm cov txheej txheem xws li cov tshuaj tiv thaiv nuclear fission saw, ntau neutrons raug tsim. Yog li ntawd, cov txheej txheem no tuaj yeem tsim cov tshuaj tiv thaiv kab mob, qhov twg neutrons yuav ua tus nqa khoom. Nyob rau hauv rooj plaub thaum tus nqi ntawm neutron captures yam tsis muaj fission los yog khiav tawm (poob tus nqi) yog compensated los ntawm tus nqi ntawm multiplication ntawm carrier hais, ces cov saw cov tshuaj tiv thaiv yuav mus nyob rau hauv ib tug nyob twj ywm hom. Qhov kev sib npaug no qhia txog qhov sib npaug. Nyob rau hauv cov ntaub ntawv saum toj no, nws yog sib npaug rau ib tug. Hauv kev siv hluav taws xob nuclear, vim yog qhov kev taw qhia ntawm qhov kev tawm tswv yim tsis zoo ntawm tus nqi ntawm lub zog tso tawm thiab qhov sib npaug, nws muaj peev xwm tswj tau qhov kev tawm tsam ntawm nuclear. Yog tias qhov coefficient no ntau dua ib qho, ces cov tshuaj tiv thaiv yuav txhim kho exponentially. Kev tswj tsis tau cov saw hlau yog siv rau hauv riam phom nuclear.
Nuclear saw cov tshuaj tiv thaiv hauv lub zog
Lub reactivity ntawm lub reactor yog txiav txim los ntawm ntau tus txheej txheem uas tshwm sim nyob rau hauv nws cov tub ntxhais. Tag nrho cov kev cuam tshuam no yog txiav txim los ntawm qhov hu ua reactivity coefficient. Cov txiaj ntsig ntawm kev hloov pauv ntawm qhov kub ntawm graphite rods, coolants los yog uranium ntawm lub reactivity ntawm lub reactor thiab qhov kev siv ntawm xws li ib tug txheej txheem raws li ib tug nuclear saw cov tshuaj tiv thaiv yog yus muaj los ntawm ib tug kub coefficient (rau coolant, rau uranium, rau graphite). Kuj tseem muaj cov yam ntxwv ntawm lub zog, nyob rau hauv cov nqe lus ntawm barometric ntsuas, nyob rau hauv cov nqe lus ntawm chav ntsuas. Yuav kom tswj tau cov tshuaj tiv thaiv nuclear hauv lub reactor, nws yog ib qho tsim nyog los hloov qee cov ntsiab lus rau hauv lwm tus. Txhawm rau ua qhov no, nws yog ib qho tsim nyog yuav tsum coj mus rau hauv tus account cov xwm txheej rau kev khiav ntawm cov tshuaj tiv thaiv kab mob nuclear - muaj cov khoom muaj peev xwm faib tawm thiab tso tawm ntawm nws tus kheej thaum lub sij hawm lwj ib co ntawm cov hauv paus ntsiab lus, uas yog vim li cas., yuav ua rau lub fission ntawm cov seem nuclei. Raws li xws li cov khoom, uranium-238, uranium-235, plutonium-239 feem ntau siv. Thaum lub sij hawm dhau los ntawm cov tshuaj tiv thaiv nuclear, cov isotopes ntawm cov ntsiab lus no yuav lwj thiab tsim ob lossis ntau dua lwm yam tshuaj. Nyob rau hauv cov txheej txheem no, lub thiaj li hu ua "gamma" rays yog emissions, ib tug mob siab heev tso tawm ntawm lub zog tshwm sim, ob los yog peb neutrons yog tsim, muaj peev xwm mus txuas ntxiv cov tshuaj tiv thaiv. Muaj cov neutrons qeeb thiab ceev ceev, vim hais tias kom lub nucleus ntawm lub atom kom tawg, cov hais yuav tsum ya ntawm ib tug ceev ceev.
