Fission ah nuclei uranium. reaction Chain. Description of habka

Qaybsadeen xudunta - fiicnin a eb culus laba jajab ah oo miisaankiisu yahay qiyaastii siman, ku xiga xoreynta xaddi weyn oo tamarta.

helitaanka fission nuclear bilowga marxalad cusub - "da'da qaaradda". ka iman kara ee loo isticmaalo in ay suurto gal ah iyo dheelitirka ee halista in ay ka faa'iideystaan oo ay la isticmaalo, ma aha oo kaliya siiyey kor u badan oo guulaha cilmiga, siyaasadeed, dhaqaale iyo cilmi ah, laakiin sidoo kale dhibaato halis ah. Xitaa ka hal dhibic kaliya sayniska of view, habka fission nuclear abuuray tiro badan oo ah xujooyinka iyo dhibaatooyin, iyo sharaxaad dhamaystiran teori waayo, waa wax ka mid ah mustaqbalka.

Sharing - faa'iido

qabanaya tamarta (per nucleon) ku kala duwan yihiin nuclei kala duwan. Culus leeyihiin tamarta hoose qabanaya ka badan in ku yaalla dhexe ee miiska wareegsan.

Taas macnaheedu waa in nuclei culus ah oo qaaradda tiro ka weyn tahay 100, advantageously qaybiyay laba jajab yar yar, oon ku sii daayo tamarta la beddelay tamarta ogeed jajabkii. Nidaamkan waxaa loo yaqaan qaybsama xuduntii qaaradda.

Iyadoo la tixraacayo qalooca xasiloonida, taas oo muujinaysa tiirsanaanta ee tirada protons ka nuclides deggan, waayo, neutron xuduntii culus door bidaan tiro badan oo neutrons badan fududee (with tirada protons marka la barbar dhigo). Tani waxay soo jeedinaysaa in lagu daro nidaamka qaybsama la timaada doonaa qaar ka mid ah neutrons "firaaqada". Intaa waxaa dheer, waxay kaloo qaadan doonaan in ka badan qaar ka mid ah tamarta la sii daayay. fission Study of atamka uranium muujisay in this abuuraa neutron a 3-4: U → ^{238 145 90} La + br + 3n.

Tirada qaaradda (iyo mass qaaradda) of jab ma qummana in qeybtii mass ee qaaradda waalidka. Farqiga u dhexeeya dadweynaha ee atamka sameeyay iyadoo ay sabab u cholesterol inta badan ku saabsan tahay 50. Si kastaba ha ahaatee, sababta this aan weli waa gebi ahaanba cad.

The tamartaa qabanaya of ²³⁸ U, ¹⁴⁵ La br iyo ⁹⁰ waa 1803, 1198 iyo 763 MeV siday u kala horreeyaan. Taas macnaheedu waa in tamarta la sii daayay fission uranium siman 1198 + 158 = 763-1803 MeV keentay ka falcelinta.

fission lama filaan ah

geeddi socodka qaybsama lama filaan ah waxaa loo yaqaan ee dabiiciga ah, laakiin aad ayay dhif u yihiin. Meyeydaan Celceliska habkan ku saabsan 10 ^{17 waa,} iyo, tusaale ahaan, uu nool yahay celceliska Alfa-suuska of radionuclide ku saabsan 10 ^{11 waa.}

Sababta tani waa in si ay u kala soocaan laba qaybood, xudunta u ah waa in marka hore mari calaamadaha lahayo (stretch) ee foomka ellipsoidal, ka dibna, ka hor inta cholesterol final laba jajab u sameeyaan a "qoorta" dhexe.

ooday iman kara

In gobolka ay maroorsamaan ee muhimka ah ee labada ciidamada. Mid ka mid ah iyaga ka mid ah - tamarta kordhay dusha (xiisadda dusha dhibcahaa dareere sharxayaa ay qaab spherical), iyo kuwa kale oo - repulsion Coulomb u dhexeeya jajabkii fission ah. Si wada jir ah ay u soo saaraan caqabad ku iman kara.

Sida ay dhacdo ee bololka Alfa inay dhacaan fission lama filaan ah nuclei uranium qaaradda, jajabkii waa in ay ka gudbaan kala ooday iyadoo loo adeegsanayo tunneling galmada. caqabad ku saabsan yahay 6 MeV, sida kiiska ee Alfa-suuska, laakiin jaaniska ah tunneling of α-qayb uga weyn yahay eb ee qaybsama wax soo saarka badan ka culus.

nabaad guurka khasabka ah

U badan tahay waxaa laaluusheen fission ah nuclei uranium. Xaaladdan oo kale, xuduntii waalidka la gubaa leh neutrons. Haddii waalidka u nuuga, ka dibna loo xidho in ay sii daayaan tamar ku qabanaya qaab tamar vibrational in ka badan karaa 6 MeV loo baahan yahay in ay ka gudbaan caqabad ku iman kara.

Halkee tamarta neutron dheeraad ah kuma filna in ay ka gudbaan caqabad ku iman kara, neutron dhacdada waa in uu leeyahay tamarta ugu yar ogeed in si ay u awoodaan si ay u abaari qaybsama la eb ee. In the case of ²³⁸ U neutron dheeraad ah tamarta qabanaya maqan yahay oo ku saabsan 1 MeV. Taas macnaheedu waa in fission ee nuclei uranium laaluusheen neutrons kaliya tamarta ah ogeed ka badan 1 MeV weyn. Dhinaca kale, ay ²³⁵ isotope U leeyahay hal neutron unpaired. Marka xuduntii a nuuga dheeraad ah, u yeela waxa ay laba iyo tamarta qabanaya dheeraad ah waa natiijo ah oo ka garab this. Tani waa ku filan in ay sii daayaan inta tamar looga baahan yahay in ay ka gudbaan caqabad ku iman kara xuduntii iyo kala qeybinta isotopes ka dhacay isku dhaceen neutron kasta.

suuska beta

In kasta oo xaqiiqda ah in uu cadaanyo fission waxaa timaada by saddex ama afar neutrons, Goosimo weli ku jira neutrons badan isobars deggan ay. Taas macnaheedu waa in jajabkii cholesterol yihiin guud ahaan deganayn si ixtiraam leh in beta suuska.

Tusaale ahaan, marka ay jirto kala qaybsameen xuduntii of uranium ²³⁸ U, isobars deggan iyadoo A = 145 ¹⁴⁵ waa neodymium nd, taas oo macnaheedu yahay in lanthanum jab ah La ¹⁴⁵ jajabo galay saddex marxaladood, mar kasta oo ay radiating electron iyo neutrino ilaa nuclide deggan waxaa la aasaasay. isobars deggan iyadoo A = 90 ⁹⁰ waa Zr zirconium, sidaas bromo jab cholesterol br ⁹⁰ jajabo shan marxaladood silsilad β-suuska.

β-suuska silsilad Kuwani dhaadheer tamar dheeraad ah kaas oo la iska dhowaad kaxaystay oo dhammu u ah electron iyo neutrino ah.

reactions Nuclear: fission of uranium

nuclide Direct ka soo shucaaca neutron tiro aad u badan oo iyaga ka mid ah si loo xaqiijiyo xasiloonida xuduntii lagama yaabo. Halkan barta waa in aysan jirin repulsion Coulomb, oo sidaas tamarta dusha ku socotaa in hayn neutron ah ay sabab u tahay waalidka. Si kastaba ha ahaatee, waxa uu mararka qaar ka dhaca. Tusaale ahaan, jab fission br ⁹⁰ ee ugu horeysay ee beta-suuska saartaa a krypton-90, kaas oo lagu ku yaalla waxaa laga yaabaa in dawlad ku faraxsan tamarta ku filan in ay ka gudbaan tamarta dusha sare. Xaaladdan oo kale waxaa laga yaabaa in shucaaca neutron si toos ah dhacaan si ay u sameeyaan krypton-89 ah. Tani isobars waa aan weli degganeyn marka la eego beta-suuska ayaa weli ma geli yttrium-89 ee deggan, si krypton-89 wuxuu u qaybsan yahay saddex marxaladood.

fission Uranium: Reaction Chain

Neutrons timaada in reaction cholesterol ee la nuugo karaa by waalidka-xuduntii kale, taas oo ka dibna Oo Qaliin fission is-laaluusheen. In the case of uranium-238 saddex neutrons, taas oo ka kac la tamartaa ka yar 1 MeV (tamarta sii daayay fission ee muhiimka ah uranium - 158 MeV - inta badan diinta Goosimo cholesterol tamarta ogeed), si ay u ma keeni kartaa kala qaybsameen dheeraad ah nuclide this. Si kastaba ha ahaatee, haddii fiirsashada weyn oo isotope dhif U ²³⁵ kuwaas neutrons free lagu qabtay karo by ah nuclei ka mid ah ²³⁵ U, waxa ay dhab ahaantii wuxuu keeni karaa cholesterol, tan iyo markii ay dhacdo in this ma jirto marinka tamarta hoose oo horyaalka aan laaluusheen.

Tani waa falcelinta silsilad mabda '.

Noocyada Xasaasiyada Nukliyeerka

Ha k - tirada neutrons soo saaray tijaabada ah ee wax fissile in n tallaabo ee silsiladda ah, oo loo qaybiyey tirada neutrons soo saaray marxaladda n - 1. Tirada Tani waxay ku xirnaan doontaa tirada neutrons soo saaray in tallaabo n - 1, waxaa lagu nuugo asaasiga ah, taas oo mari karaa fission laaluusheen.

• Haddii k <1 on, reaction silsilad waa fudud ka soo uumi iyo habka aad si deg deg ah u joojiyaan doonaa. Tani waa waxa dhaca dabiiciga ah ore uranium, taas oo fiirsashada ^{of 235} U waa yar yihiin in jaaniska ah nuugista neutron a isotope tani waa mid aad u dayac badan.

• Haddii k> 1, reaction silsiladda sii si ay u koraan iyo inta uu dhan ee wax fissile ah oo aan la isticmaali doonaa (bamka qaaradda). Taana waxaa lagu gaarayaa by kobciya ore dabiiciga ah si aad u hesho uruuray ku filan sare ee uranium-235. Waayo, spherical qiimaha saamiga k kordhaa jaaniska ah nuugista neutron, taas oo ku xidhan tahay gacan ah ee ka howgala. Sidaa darteed miisaanka U waa in ka badan ka tiro badan qaar in fission of uranium (reaction silsilad) dhici kara.

• Haddii k = 1, ka dibna waxaa jira falcelin gacanta. Waxa loo isticmaalaa in tigoodu nuclear. Geedi socodka gacanta qaybinta dhengedihii uranium of cadmium ama boron, kaas oo uu u nuugo inta badan neutrons dhexdooda (walxahaasi awood u qabsaday neutrons). Qaybsadeen diirkja uranium, waxaa si toos ah ay gacanta ku dhaqaaqin ushii si qiimaha k weli loo siman yahay mid ka mid ah.