Ukuhluma kwe-uranium nucleus. Indlela yokuphendula. Inkcazo yenkqubo

Ukwahlula kwe-nucleus kukuqhekeka kwe-atom eninzi kwiingqungquthela ezimbini ezilingana nobunzima obulinganayo, ezihamba kunye nokukhululwa kwamandla amakhulu.

Ukufunyanwa kwenkcubeko yenyukliya kwathatha ixesha elitsha - "i-atomic age". Ubungakanani bokusetyenziswa kwayo kunye nomyinge wengozi ekuzuzeni kwisicelo sakhe akuzange kwenzeke kuphela kwiimpumelelo ezininzi zentlalo, ezopolitiko, ezoqoqosho nezenzululwazi, kodwa neengxaki ezinzulu. Ngaphandle kwendlela yokujonga i-science, inkqubo ye-fission yenyukliya yenze inqwaba yeepuzzle kunye neengxaki, kwaye ingcaciso epheleleyo yeengxelo yinkalo yekamva.

Yabelana - inzuzo

Amandla okubopha (nge-nucleon) yeenucleucle ezahlukeneyo. Iimpawu ezinzima zinamandla angaphantsi okubophayo kunabo abakuphakathi kwetafile yexesha.

Oku kuthetha ukuba i-nuclei enzima, apho inani le-athomu likhulu kunama- 100, lihlukana ngokuhlukileyo kwiingxenyana ezincinci, ngaloo ndlela zikhulula amandla aguqulwa abe yi-kinetic yamagqabi. Le nqubo ibizwa ngokuba ukwahlukana kwe- nucleus ye- athomu.

Ngokuhambelana nesigxina sokuzinza, esibonisa ukuxhomekeka kwenani leeponononi kwinani le-neutron kwii-nuclides ezizinzile, i-nuclei eyinkulu ikhetha inani elikhulu le-neutron (xa kuthelekiswa nenani leeponononi) kunezibane. Oku kuphakamisa ukuba kunye nenkqubo yokwahlukana, ezinye i-neutron ziza kukhutshwa. Ukongeza, baya kuthatha inxalenye yamandla abelwe. Ukufundwa kwe-fission ye-nucleus ye-athomu ye-uranium kubonise ukuba i-neutron 3-4 ikhutshwa ngeli xesha: ²³⁸ U → ¹⁴⁵ La + ⁹⁰ Br + 3n.

Inombolo ye-athomu (kunye ne-atomic mass) yeli qhekeza ayilingani nesiqingatha se- atomic yomzali. Ukwahlukana phakathi kwemimandla yee-atom eyenziwe ngenxa yokuqhekeka ngokuqhelekileyo kudla malunga ne-50. Nangona kunjalo, isizathu sokuba oku asiqondanga ngokupheleleyo.

Amandla okubopha ama- ²³⁸ U, ¹⁴⁵ La ne- ⁹⁰ Br alingana ne-1803, 1198 no-763 MeV ngokulandelanayo. Oku kuthetha ukuba ngenxa yempendulo, amandla e-fission e-uranium nucleus akhululwa, alingana no-1198 + 763-1803 = 158 MeV.

Ukwahlukana ngokukhawuleza

Iinkqubo zokuqhekeka ngokukhawuleza ziyaziwa kwindalo, kodwa zincabile kakhulu. Umyinge wokuphila wale nkqubo u malunga neminyaka eyi- ^10-17 , kwaye, umzekelo, ixesha lokuphila eliqhelekileyo lokubola kwe-alpha ye-radionuclide efanayo li malunga neminyaka eyi-10 ¹¹ .

Isizathu salokhu kukuba ukuze ukwahlukana zibe ngamacandelo amabini, umgaqo-siseko kufuneka uqale udibaniswe (wolule) ube ngumbono we-ellipsoidal, kwaye ke, ngaphambi kokugqitywa kokugqibela zibe ziqhekeza ezimbini, yakha "intamo" phakathi.

Umngcipheko

Kwimeko ephosakeleyo, amabini amabutho enza into ephambili. Omnye wabo kukunyuka kwamandla angaphezulu (ukuphazamiseka komhlaba wehla lokuhlambalaza kuchaza isimo sawo siphezulu), enye enye i-Coulomb repulsion phakathi kwee-fission fragments. Bonke bavelisa umqobo onokubakho.

Njengoko kwimeko yokubola kwe-alpha, i-fission ye-atom ye-atomi ye-uranium ivela ngokukhawuleza, iinqununu kufuneka zinqobe le mqobo ngokulandelwa kwe-quantum. Ixabiso lesithintelo li malunga ne-6 MeV, njengoko kwimeko yokubola kwe-alpha, kodwa ubuchule bokunxibelelana kwe-α inxalenye enkulu kunomkhiqizo onzima kakhulu we-atom ukwahlukana.

Ukwahlukana

Kuninzi kunokwenzeka ukuba i-fission ekwenziwe yikhunyu ye-uranium. Kule meko, i-nucleus yomama ixiliswe nge-neutron. Ukuba umzali uyayifumana, ibopha, ikhulule amandla okubophayo ngendlela yombane onamandla, onokudlula ngaphezu kwe-6 MeV, eyimfuneko yokunciphisa umnqamlezo.

Apho amandla e-neutron eyongezelelweyo engenelanga ukwenzela ukunqoba umqobo onokubakho, isiganeko se-neutron kufuneka sibe neyona minye yamandla ekineti ukwenzela ukuba ikwazi ukukhupha i-athomu. Kwimeko ye- ²³⁸ U, amandla okubopha i-neutron ezongezelelweyo ayifutshane ne-1 MeV. Oku kuthetha ukuba i-fission ye-uranium nucleus ifakwe kuphela nge-neutron ene-kinetic yamandla ngaphezu kwe-1 MeV. Ngakolunye uhlangothi, i-isotope ²³⁵ U ine-neutron enye engaphili. Xa i-nucleus ibamba enye eyongezelelweyo, yenza idilesi kunye nayo, kwaye ngenxa yolu bhanqa unamandla angaphezulu okubophayo kubonakala. Oku kunelungelo lokukhulula umlinganiselo wamandla afanelekileyo kumgaqo-siseko wokunqoba umqobo onokubakho kwaye ukwahlukana kwe-isotope kwenzeka xa uhamba kunye naluphi na i-neutron.

Ukubola kweBeta

Nangona i-neutron yesithathu okanye enye iphuma kwi-reaction fission, iziqhekeza zisenalo i-neutron ngaphezulu kune-isobars ezizinzile. Oku kuthetha ukuba iinqununu zokuqhawula, ngokusemthethweni, zizinzile malunga nokubola kwe-beta.

Ngokomzekelo, xa i-fission ye-uranium nucleus ingama- ²³⁸ U, isobar ene-A = 145 i-neodymium ¹⁴⁵ Nd, oku kuthetha ukuba iinqununu ze-lanthanum ¹⁴⁵ Ukubola kwinqanaba eli-3, ngexesha ngalinye elikhupha i-electron kunye ne-antineutrinos de i-nuclide ezinzile. I-isobar esisigxina nge-A = 90 yi-zirconium ⁹⁰ Zr, ngoko ke, isahlulo sokuqhekeza se-bromine i- ⁹⁰ Br siyanqumla kwiinqanaba ezihlanu ze-β-decay chain.

Ezi ntlobo ze-β-decay zifaka amandla angaphezulu, aphethwe ngokupheleleyo ngama-electron kunye ne-antineutrinos.

Iimpendulo zenyukliya: i-fission ye-uranium nuclei

Ukukhanya kwe-radiation ye-neutron kwi-nuclide eninzi kakhulu ukuqinisekisa ukuba ukuzinza kwe-nucleus akunakwenzeka. Nanku into into yokuba akukho nto i-Coulomb ishicilelwe kuyo, ngoko ke amandla ophezulu agcina ukubamba i-neutron ngokumalunga nomzali. Nangona kunjalo, ngezinye ixesha kwenzeka. Ngokomzekelo, isiqwenga sokwahlukana kwe- ⁹⁰ Br kwisigaba sokuqala sokubola kwe-beta kuvelisa i-krypton-90, enokuba yimeko evuyisayo enegunya elaneleyo lokunqoba amandla omhlaba. Kule meko, imisebe ye-neutron inokuvela ngqo ngokubunjwa kwe-krypton-89. Le i-isobar isengenakulinganiswa ngokubhekiselele kwi-β-ukubola kuze kube yttrium-89, ukuze i-krypton-89 ibonakale kwiinqanaba ezintathu.

Ukuhluma kwe-uranium nuclei: ukuphendulwa kwesikrini

I-neutron ekhutshwe kwi-reaction ye-cleavage inokubanjelwa enye i-nucleus yomzali, leyo yona ngokwayo iphinde iqhube i-fission. Kwimeko ye-uranium-238, i-neutron ezintathu eziphakamayo zivela ngamandla angaphantsi kwe-1 MeV (amandla akhululwe kwi-fission ye-uranium nucleus-158 MeV-ngokuyisisekelo ewela emandleni okuqhawula amaqhekeza aqhekekileyo), ngoko awanako ukudala ukukhushulwa kwe-nuclelide. Nangona kunjalo, kwi-concentration ye-isotope engabonakaliyo engu- ²³⁵ U, le i-neutron yamahhala inokuthi ifakwe ngama- ²³⁵ U-nuclei, eyona nto ingabangela ukuhlukana, kuba kungalolu hlobo akukho mandla engezansi apho i-fission ingenakunyuswa.

Nguwo umgaqo wendlela yokusabela ngayo.

Iintlobo zeempendulo zenukliya

Masibe inani leetyutheni eziveliswe kwisampuli yezinto ezifakwe kwi-stage n yale kholeji eyahlula ngenani leetyutron ekwakhiwa kwinqanaba n-1. Le nani iya kuxhomekeka kwindlela ezininzi ezithatha i-neutron ezifunyenwe kwisigaba n-1 zithathwa yi-nucleus, Unako ukuhlulwa ngokunyanzeliswa.

• Ukuba k <1, ukuphendulwa kwekhenketho kuya kufa kwaye inkqubo iya kukhawuleza ngokukhawuleza. Yiyo kanye eyenzekayo kwindalo ye- uranium yemvelo , apho ukuxinwa kwe- ²³⁵ U kuncinci kangangokuthi ukuxhamla komnye we-neutron yi-isotope ayiyona nto ibaluleke kakhulu.

• Ukuba i-k> 1, i-reaction chain iyakwandisa de kube zonke izinto ezisetyenzisiweyo (ibhomu ye-athomu). Oku kuphunyezwe ngokuphucula i-ore yemvelo ukuya kwi-uranium-235 ephezulu. Isampuli esisezantsi, ixabiso le k liyakhula ngokunokwenzeka ukwanda kwe-neutron, exhomekeke kumda webala. Ngoko ke, ubunzima be-U kufuneka bugqithise ubunzima obunzima, ukwenzela ukuba i-fission ye-uranium nuclei (impendulo yeeketri) inokwenzeka.

• Ukuba k = 1, ukuphendulwa okulawulwayo kwenzeka. Oku kusetyenziswa kwiirakhi zenyukliya. Inkqubo ilawulwa ngokusabalalisa phakathi kweentambo ze-uranium ze-cadmium okanye i-boron, ezithatha ininzi ye-neutron (ezi zinto zinokukwazi ukuthatha i-neutron). I-fission ye-core ye-uranium ilawulwa ngokuzenzekelayo ngokuhambisa iintonga ngendlela enokuthi ixabiso lek lihlala lilingana nobunye.