Fission a mtima ureniamu. Unyolo anachita. Kufotokozera za ndondomeko

Kugawa pachimake - waukulu atomu akuwaza mu zidutswa ziwiri za kulemera pafupifupi wofanana, kenako anamasulidwa wambirimbiri mphamvu.

Kupezeka kwa nyukiliya fission chiyambi cha nyengo yatsopano - "atomiki zaka". Lingathe ntchito yake zotheka ndi muyezo wa chiopsezo kupindula ntchito yake, osati wafunsira kwambiri mwa zinthu sociological, ndale, chuma ndi sayansi, koma ndi vuto lalikulu. Ngakhale ku mfundo mwangwiro sayansi view, nyukiliya fission ndondomeko analenga ambiri a masamu ndi mavuto, ndi wathunthu mafotokozedwe ongolankhula kuti ndi chinthu cha tsogolo.

Kugawana - opindulitsa

kumanga mphamvu (pa nucleon) amasiyana mtima osiyana. Ankawonjezereka ndi m'munsi kumangako mphamvu kuposa kuti m'katikati mwa tebulo nthawi.

Izi zikutanthauza kuti mtima waukulu umene atomiki chiwerengero choposa 100, advantageously ogaŵikana zidutswa ziwiri zing'onozing'ono, potero kumasuka mphamvu kuti n'kukhala mphamvu kayendedwe wa makombo. Zimenezi amatchedwa akuwaza atomiki phata.

Malinga ndi mtendere pamapindikira, imene ikusonyeza kudalira chiwerengero cha mapulotoni ku nuclides khola kwa nyutironi phata ankawonjezereka amakonda nambala yaikulu ya neutrons (poyerekeza ndi kuchuluka kwa mapulotoni) kuposa mbandakucha. Izi zikusonyeza kuti kuwonjezera pa ndondomeko akuwaza adzakhala panamveka ena "yopuma" neutrons. Komanso, inunso kutenga ena mwa mphamvu anamasulidwa. Phunziro fission maatomu ureniamu anasonyeza kuti amapanga nyutironi 3-4: U → ^{238 145 90} La + br + 3n.

Nambala atomiki (ndi misa atomiki) a mpukutu si wolingana ndi theka misa atomiki kholo la. Kusiyana ambirimbiri maatomu anapanga chifukwa cha pogawanikana pamawere ndi zambiri za 50. Komabe, chifukwa cha izi si mpemphero kwathunthu.

Mphamvu ankameteramo ubweya wa ²³⁸ U, ¹⁴⁵ La br ndi ⁹⁰ ndi 1803, 1198 ndi 763 MeV motero. Izi zikutanthauza kuti mphamvu adzamasulidwa ureniamu fission ofanana 1198 + 158 = 763-1803 MeV chifukwa zotani.

mowiriza fission

mowiriza njira akuwaza amadziwika mu chilengedwe, koma iwo n'zochepa kwambiri. The moyo avareji ndondomeko izi ndi pafupifupi 10 ^{17 ndipo} Mwachitsanzo, yamoyo avareji alpha-kuvunda kwa radionuclide ndi za 10 ¹¹ m.

Chifukwa cha ichi ndi kuti kupatukana pawiri, pachimake choyamba tiyenera kukumana ndi mapindikidwe (Tambasula) mu mawonekedwe ellipsoidal, ndipo isanafike pogawanikana pamawere komaliza mu zidutswa ziwiri kupanga "khosi" pakati.

chotchinga kuthekera

M'chigawo opunduka pa maziko a magulu awiri. Mmodzi wa iwo - chinawonjezeka pamwamba mphamvu (padziko mavuto m'malovu madzi anafotokoza mawonekedwe ake ozungulira), ndi zina - ndi Coulomb repulsion pakati makombo fission. Pamodzi iwo amapanga chotchinga angathe.

Monga zinachitikira Alpha kuwola kulankhula mowiriza fission wa ureniamu atomiki mtima, makombo ayenera muthane ndi vuto limeneli mwa kwadzidzidzi tunneling. The zopinga za 6 MeV, monga zinachitikira alpha-kuwola, koma Mwina tunneling wa α-particles ndi wamkulu kwambiri kuposa kwambiri ankawonjezereka mankhwala akuwaza atomu.

amakakamizidwa kudzitsitsa

Nthawi zambiri amakhala ndi anachititsa fission a mtima ureniamu. Pankhaniyi, kholo phata ndi irradiated ndi neutrons. Ngati kholo izo zimatenga, ndiye iwo omangidwa ndi kumasula mphamvu kumanga mu mawonekedwe a mphamvu vibrational kuti akhoza upambana MeV 6 anafunika kugonjetsa chotchinga angathe.

Kodi zina nyutironi mphamvu sikokwanira kugonjetsa chotchinga kuthekera, chochitika nyutironi ayenera kukhala osachepera kayendedwe mphamvu kuti athe kupangira akuwaza wa maatomu. Pankhani ya ²³⁸ U zina nyutironi mphamvu kumangako chikusowekabe 1 MeV. Izi zikutanthauza kuti fission a mtima ureniamu anachititsa neutrons yekha ndi mphamvu kayendedwe kuposa 1 MeV. Komano, pa ²³⁵ U isotope mmodzi unpaired nyutironi. Pamene phata zimatenga zina, ndipamene nazo angapo ndi zina kumangako mphamvu chifukwa cha Kumuyika izi. Izi ndi chokwanira kuti amasule kuchuluka kwa mphamvu zokwanira kuthetsa chotchinga angathe phata ndi gulu la isotopes zinachitika mu kuwombana nyutironi iliyonse.

beta kuwola

Ngakhale kuti fission anachita ali panamveka ndi neutrons atatu kapena anayi, zidutswa akadali muli neutrons kuposa isobars awo khola. Izi zikutanthauza kuti pogawanikana pamawere zidutswa zambiri wosakhazikika ndi kulemekeza beta kuwonongeka.

Mwachitsanzo, pamene pali gulu la phata la ureniamu ²³⁸ U, isobars khola ndi A = 145 ¹⁴⁵ ndi neodymium na-, kutanthauza kuti mpukutu lanthanum La ¹⁴⁵ linagawanika mu magawo atatu, nthawi iliyonse ndi yochokera elekitironi ndi neutrino mpaka nuclide khola aumbike. isobars khola ndi A = 90 ⁹⁰ ndi zirconium Zr, kotero pogawanikana pamawere mpukutu bromo br ⁹⁰ linagawanika mu zisanu magawo unyolo β-kuwonongeka.

Izi β-kuwola unyolo zimatulutsa mphamvu zapadera amene adatengedwa lonse la elekitironi ndi neutrino.

zochita nyukiliya: fission wa ureniamu

Direct nuclide ku cheza nyutironi ndi chiwerengero chachikulu kwambiri cha iwo kuonetsetsa mtendere wa phata n'zokayikitsa. Apa mfundo ndi kuti palibe repulsion Coulomb, ndi mphamvu padziko amamuchititsa nawobe nyutironi chifukwa kholo la. Komabe, nthawi zina zimachitika. Mwachitsanzo, fission mpukutu br ⁹⁰ choyamba beta-kuwola umabala krypton 90, kumene ili mu boma okondwa ndi mphamvu chokwanila kugonjetsa mphamvu pamwamba. Pankhaniyi nyutironi cheza kumachitika mwachindunji kupanga krypton 89. Izi isobars akadali wosakhazikika ndi kulemekeza beta-kuwola sanabadwe kupita mu khola yttrium 89, kotero kuti krypton 89 lagawidwa masiteji atatu.

Ureniamu fission: unyolo Chisoni

Neutrons panamveka mu pogawanikana pamawere anachita akhoza chosakanikirana ndi zina makolo ndi phata kenako amaloŵamo kudziletsa anachititsa fission. Pankhani ya ureniamu-238 neutrons atatu, amene uka ndi mphamvu zosakwana 1 MeV (mphamvu anamasulidwa mu fission wa ureniamu pachimake - 158 MeV - makamaka n'kukhala kayendedwe zidutswa mphamvu pogawanikana pamawere), choncho iwo sangasankhe kugawanika zina za nuclide izi. Komabe, ngati ndende yofunika kwambiri kawirikawiri isotope U ²³⁵ izi neutrons ufulu akhoza anagwidwa ndi mtima wa ²³⁵ U, izo atha kuyambitsa pogawanikana pamawere, kuyambira Pankhaniyi palibe pakhomo mphamvu pansipa magawano si anachititsa.

Izi ndi mfundo unyolo anachita.

Mitundu mosiyanasiyana nyukiliya

Tiyeni K - chiwerengero cha neutrons opangidwa ku nyemba za fissile zinthu mogwirizana N wa unyolo, anagawa ndi nambala ya neutrons opangidwa ku siteji N - 1. chiwerengero Izi zimadalira chiwerengero cha neutrons opangidwa mogwirizana N - 1, ndi chosakanikirana ndi pakati, amene akhoza kukumana anachititsa fission.

• Ngati K <1, unyolo anachita ndi basi nthunzi komanso ndondomeko adzaleka mofulumira kwambiri. Izi ndi zomwe zimachitika mu chithupi ureniamu miyala, imene ^{ambiri 235} U ndi ang'onoang'ono kwambiri motero kuti Mwina wa mayamwidwe wa nyutironi isotope izi negligible kwambiri.

• Ngati K> 1, unyolo anachita adzapitiriza kukula malinga onse a nkhani fissile sati ntchito (bomba la atomiki). Izi zimatheka ndi zawachitikira miyala zachilengedwe kupeza ndende mokwanira mkulu wa ureniamu-235. Pakuti ozungulira K ukuwonjezeka chitsanzo phindu ndi Mwina nyutironi mayamwidwe, amene amadalira pa utali wozungulira wa dera la. Choncho U kulemera ayenera upambana misa ena ovuta fission wa ureniamu (unyolo anachita) ungachitike.

• Ngati K = 1, ndiye pali anachita ankalamulira. Ndi ntchito ya nyukiliya. Dongosololi ukulamulidwa kugawa pakati ndodo ureniamu wa cadmium kapena boron, chimene timadya ambiri neutrons ndi (zinthu izi angathe yolanda neutrons). Kugawa mitima ureniamu izo basi olamulidwa ndi kusuntha ndodo kuti phindu K amakhalabe Angafanane ndi.