Fission ka-uranium nuclei. Chain reaction. Incazelo yenqubo

Kwehlukanisa nengaphakathi - elisindayo athomu eqhekeza ku ezimbili izinsalela isisindo okungenani zilingana, kulandele kukhululwa kwebantfu semali amandla.

Ukutholakala ubungako bokudlulisa kuqale inkathi entsha - "yobudala-athomu." Neqiniso lokuthi ukusetshenziswa kwayo kungenzeka futhi ibhalansi ingozi ukuzuza ukusetshenziswa kwaso, hhayi kuphela emenza eziningi impumelelo lwezenhlalo, ezombusazwe, ezomnotho, noma ezesayensi kodwa nakho kuyinkinga enkulu. Ngisho Ngokombono ongokwesayensi, zenuzi ukuqoqwa inqubo wadala inani elikhulu puzzle kanye nezinkinga, futhi ephelele incazelo ezicatshangelwayo zezinkolelo-ke into esizayo.

Ukwabelana - nenzuzo

ngibopha amandla (ngayinye nucleon) kuhluke nuclei ezahlukene. Esinda abe namandla aphansi esibophezelayo kunalokho etholakala maphakathi ishadi lesikhathi.

Lokhu kusho ukuthi nuclei esindayo lapho le-athomu inombolo enkulu kuno 100, advantageously ihlukaniswe kuzicucu ezimbili ezincane, ngaleyo ndlela ukukhulula amandla ukuthi iguqulwe ibe energy kinetic ka izingcezwana. Le nqubo ibizwa ngokuthi eqhekeza nucleus yama-athomu.

Ngokuhambisana ijika ukuzinza, elibonisa ukwencika inani proton kusukela nuclides esiqinile neutron nucleus ngoyisiwula kusinda uncamela inombolo enkulu neutrons (uma kuqhathaniswa nesibalo proton) kuka elula. Lokhu kusikisela ukuthi ngaphezu inqubo eqhekeza uzobe sasikhipha ezinye neutrons "esikhululekile." Ngaphezu kwalokho, nani bayakunizingela zilawule ezinye amandla ikhishwe. Isifundo ukuqoqwa zama-athomu uranium sabonisa ukuthi lo edonsa i-neutron 3-4: U → ^{238 145 90} La + Br + 3n.

Inombolo yama-athomu (futhi ungqimba le-athomu) kulesi siqeshana akulingani isigamu mass-athomu ye-umzali. Umehluko emkhatsini wesisindvo ama-athomu kwakhiwa ngenxa cleavage ngokuvamile-50 Nokho, isizathu salokhu akakabi kucace ngokuphelele.

Amandla yokubopha ²³⁸ U, ¹⁴⁵ La Br futhi ⁹⁰ 1803, 1198 futhi 763 MeV ngokulandelana. Lokhu kusho ukuthi amandla ikhishwe uranium ukuqoqwa alinganayo 1198 + 158 = 763-1803 MeV okubangelwa ukusabela.

ukuqoqwa nokuguqulwa

nokuguqulwa eqhekeza izinqubo zaziwa ngokwemvelo, kodwa ivelakancane. I sokuphila komuntu esivamile yale nqubo imayelana 10 ^17, futhi, isibonelo, sokuphila komuntu esivamile alpha-ukubola radionuclide imayelana 10 ^11.

Isizathu salokhu wukuthi ukuze ukuhlukanisa izingxenye ezimbili, umongo kufanele uqale ibhekane ukusonteka (elula) e ifomu ellipsoidal, bese, ngaphambi cleavage sokugcina ku kuzicucu ezimbili akha "entanyeni" phakathi.

isithiyo ezingaba

In the state sikhubazekile siwumgogodla amabutho amabili. Omunye wabo - anda surface amandla (ngaphandle ukungezwani amaconsi ketshezi uchaza ezakheke eyindilinga), kanye nezinye - the Coulomb umuzwa wokwenyanya phakathi kwezingcezu ukuqoqwa. Ndawonye kuzala bezikhali isithiyo.

Njengoba kwaba njalo endabeni ka-alpha kwamazinyo lifika ukuqoqwa okuzenzakalelayo uranium-athomu nuclei, izingcezwana kumele lo mgoqo esebenzisa mhubhe quantum. Umgoqo imayelana 6 MeV, njengoba kwaba njalo endabeni ka-alpha-kwamazinyo, kodwa ematfuba mhubhe of α-izinhlayiya itsatfwa mkhulu kunezinhliziyo olunesisindo esikhudlwana lwaluba kakhulu umkhiqizo eqhekeza athomu.

nokucekelwa ophoqelelwe

Okuningi Cishe unxenxwa ukuqoqwa of uranium nuclei. Kulokhu, i-nucleus umzali zishiswe ngemisebe neutrons. Uma umzali bumunca ke beboshwa ukukhulula amandla ngibopha ngesimo amandla vibrational ezingaba ngaphezu kuka 6 MeV adingekayo ukuze nginqobe lo engaba isithiyo.

Lapho ezengeziwe neutron amandla akwanele ukuba akwazi ukunqoba izingqinamba ezingaba isithiyo,-neutron sigameko kumele abe namandla ubuncane kinetic ukuze bakwazi ntombazane wokuqhekeka ye-athomu. Endabeni ²³⁸ U-neutron ezengeziwe amandla esibophezelayo sishoda mayelana 1 MeV. Lokhu kusho ukuthi ukuqoqwa of uranium nuclei eyenga neutrons kuphela energy kinetic mkhulu kunezinhliziyo 1 MeV. Ngakolunye uhlangothi, ^i-235 U IKhompyuthaYami has eyodwa neutron ayibhangqiwe. Lapho i-nucleus ubamba ezengeziwe, akha ngayo umbhangqwana futhi eneji olwengeziwe esibophezelayo kuyinto yalokhu ukubhanqa. Lokhu kwanele ukukhulula inani amandla awadingayo yokunqoba isithiyo esibangwa bezikhali nucleus futhi division of isotopes zenzeke ukushayisana nanoma iyiphi i-neutron.

kwamazinyo Beta

Naphezu kweqiniso lokuthi ukusabela ukuqoqwa kuthiwa wukukhanya neutrons ezintathu noma ezine, babutha izingcezwana eziyizinsalela namanje aqukethe neutrons ezingaphezu kuka isobars sabo. Lokhu kusho ukuthi izingcezwana cleavage ngokuvamile engazinzile maqondana beta kwamazinyo.

Ngokwesibonelo, lapho is a division of i-nucleus ye-uranium ²³⁸ U, isobars esitalini A = 145 ¹⁴⁵ kuyinto Nd neodymium, okusho ukuthi kwakheka lanthanum isinqamu La ¹⁴⁵ lihlukaniseka izigaba ezintathu, isikhathi ngasinye by imbuthuma electron kanye neutrino kuze kube nuclide esitebeleni is. isobars Esitebeleni nge-A = 90 ⁹⁰ kuyinto zirconium Zr, ngakho cleavage isinqamu bromo Br ⁹⁰ lihlukaniseka ezinhlanu izigaba uchungechunge β-kwamazinyo.

Lezi β-kwamazinyo uchungechunge ezishisa kakhulu zikhipha izinhlayiyana amandla xaxa okuyinto wathumba cishe yonke i-electron kanye neutrino.

ukusabela Nuclear: ukuqoqwa of uranium

nuclide okuqondile kuvela neutron emisebeni nge inani elikhulu kakhulu babo ukuqinisekisa ukuzinza nucleus akunakwenzeka. Lapha iphuzu lapha liwukuthi akukho umuzwa wokwenyanya Coulomb, ngakho amandla ebusweni ivame ukuba kugcine neutron ngenxa umzali. Noma kunjalo, ngezinye izikhathi kuyenzeka. Ngokwesibonelo, ukuqoqwa isinqamu Br ⁹⁰ yokuqala beta-kwamazinyo kuveza Krypton-90, okungenzeka akhiwe esimweni ngesasa amandla anele ukuba unqobe amandla kwamanzi. Kulokhu emisebeni neutron kungenzeka ngqo akha Krypton-89. Lokhu isobars namanje engazinzile maqondana beta-kwamazinyo ongakabi bangene yttrium-89 ezinzile, ukuze Krypton-89 ihlukaniswe izigaba ezintathu.

Uranium ukuqoqwa: Chain Reaction

Neutrons sasikhipha ekusabeleni cleavage kungenziwa amuncwa omunye umzali-nucleus, okuyinto ke sibhekana ukuqoqwa self-eyenga. Endabeni nokwe-uranium-238 neutrons ezintathu, okuyinto avele nge amandla esingaphansi 1 MeV (amandla zakhishwa ukuqoqwa of uranium core - 158 MeV - ikakhulukazi ibe kinetic namandla cleavage izingcezwana), ngakho-ke abakwazi kungadala ukwahlukana eminye yale nuclide. Nokho, uma zizithola enkulu IKhompyuthaYami ezingavamile ^U-235 kulezi neutrons khulula kungenziwa bathunjwa nuclei of ²³⁵ U, kungaba empeleni ngibangele cleavage, kusukela kulokhu kungekho embundwini amandla ngezansi lapho sigaba hhayi eyenga.

Lesi isimiso chain reaction.

Izinhlobo Ukusabela Nuclear

Ake k - nenani neutrons akhiqizwa isampula impahla fissile ngesinyathelo n yochungechunge, ihlukaniswe ngenani neutrons akhiqizwa esiteji n - 1. Le nombolo kuzoncika inani neutrons akhiqizwa isinyathelo n - 1, kuthiwa amuncwa core, okuyinto ungakwazi ibhekane ukuqoqwa eyenga.

• Uma k <1 sivulekile, ukusabela chain kumane aphume umusi kanye inqubo uzoyeka ngokushesha okukhulu. Yilokhu okwenzekayo kule yemvelo -uranium-ore, lapho ^{lokuhlushwa 235} U lincane kangangokuthi ematfuba ukumuncwa neutron lokhu IKhompyuthaYami azinakwa kakhulu.

• Uma k> 1, ukusabela chain bayoqhubeka bekhula nje yonke impahla fissile ngeke sisetshenziswe (i-ibhomu le-athomu). Lokhu ibangelwa ekwandiseni ore zemvelo ukuthola lokuhlushwa ngokwanele eliphezulu nokwe-uranium-235. Ukuze eyindilinga isampula ukubaluleka k kwanda amathuba neutron ukumuncwa, okuyinto sincike engaba sithombe. Ngakho U isisindo kumele singeqi mass ezithile ezibucayi ukuqoqwa of uranium (chain reaction) kungahle kube khona.

• Uma k = 1, ke kukhona ukuphendula elawulwa. It is lisetshenziswe Kuneziteshi zamandla enuzi. Inqubo ilawulwa ukusatshalaliswa phakathi uranium izinti cadmium noma boron, okuyinto ukuncela iningi neutrons (lezi zinto ziyakwazi ekuthumbeni neutrons). Kwehlukanisa uranium cores it is ngokuzenzakalelayo ilawulwa ezihambayo induku ukuze ukubaluleka k uhlala lingana kuze fike.