The poizoniyu kuwonongeka kwa graphite ufa ali kwambiri zimakhudza luso ndi zachuma ntchito riyakitala, makamaka mwala bedi kutentha mpweya utakhazikika riyakitala. Limagwirira wa nyutroni moderation ndi zotanuka kumwazikana manyuturoni ndi maatomu a zinthu moderating, ndipo mphamvu zonyamulidwa ndi iwo amasamutsidwa kwa maatomu a zinthu moderating. Graphite ufa ndiwofunikanso kulonjeza zazinthu zokhala ndi plasma zopangira zida zanyukiliya. Olemba otsatirawa ochokera ku Fu Ruite akuwonetsa kugwiritsa ntchito ufa wa graphite pamayeso a nyukiliya:
Ndi kuwonjezeka kwa neutron momveka bwino, ufa wa graphite umayamba kuchepa, ndipo utatha kufika pamtengo wochepa, shrinkage imachepa, imabwereranso kukula kwake, kenako imakula mofulumira. Kuti agwiritse ntchito bwino ma neutroni otulutsidwa ndi fission, ayenera kuchepetsedwa. The matenthedwe zimatha graphite ufa anapezedwa ndi walitsa mayeso, ndi walitsa kuyezetsa mikhalidwe ayenera kukhala chimodzimodzi ndi mmene ntchito zenizeni riyakitala. Njira ina yopititsira patsogolo kagwiritsidwe ntchito ka ma nyutroni ndikugwiritsa ntchito zinthu zowunikira kuti ziwonetse manyutroni omwe akutuluka munyutulo ya nyukiliya yotchedwa zone-core back. Kachitidwe ka nyutroni kunyezimira ndikumwaza zotanuka kwa ma neutroni ndi ma atomu a zinthu zowunikira. Pofuna kuwongolera kutayika komwe kumachitika chifukwa cha zonyansa kumlingo wovomerezeka, ufa wa graphite womwe umagwiritsidwa ntchito mu riyakitala uyenera kukhala wa nyukiliya woyera.
Nuclear graphite powder ndi nthambi ya zida za graphite za ufa zomwe zidapangidwa potengera zosowa zomanga zida zanyukiliya koyambirira kwa 1940s. Amagwiritsidwa ntchito ngati oyang'anira, zowunikira komanso zomangika pamakina opanga, ma reactors oziziritsidwa ndi gasi komanso ma reactors otenthetsera kwambiri. Kuthekera kwa neutroni kumachita ndi phata limatchedwa gawo la mtanda, ndipo nyutroni yotentha (avereji yamphamvu ya 0.025eV) fission cross section ya U-235 ndi magiredi awiri apamwamba kuposa fission neutron (avareji yamphamvu ya 2eV) fission cross section. . The zotanuka modulus, mphamvu ndi liniya kukulitsa coefficient of graphite ufa amawonjezeka ndi kuwonjezeka kwa neutron fluence, kufika pamtengo waukulu, ndiyeno kuchepa mofulumira. Kumayambiriro kwa zaka za m'ma 1940, ufa wokha wa graphite unalipo pamtengo wotsika mtengo pafupi ndi chiyero ichi, chifukwa chake makina onse opangira magetsi ndi makina opangira makina ankagwiritsa ntchito ufa wa graphite ngati zinthu zochepetsera, zomwe zimabweretsa zaka za nyukiliya.
Chinsinsi chopanga isotropic graphite ufa ndi kugwiritsa ntchito tinthu tating'onoting'ono tomwe timakhala ndi isotropy yabwino: isotropic coke kapena macro-isotropic yachiwiri ya coke yopangidwa kuchokera ku anisotropic coke, ndipo ukadaulo wachiwiri wa coke umagwiritsidwa ntchito pakali pano. Kukula kwa kuwonongeka kwa radiation kumakhudzana ndi zopangira za ufa wa graphite, njira zopangira, kuthamanga kwa neutroni komanso kusinthasintha kwamphamvu, kutentha kwamagetsi ndi zinthu zina. Boron yofanana ndi nyukiliya ya graphite ufa imayenera kukhala yozungulira 10 ~ 6.
Nthawi yotumiza: May-18-2022