Abstract
The amounts of fission products and uranium on an aluminium collector, which was placed near toU-Alalloys andUmetals during the neutron irradiation, were determined by gamma ray spectrometry using aGe (Li) detector and by fission tracks on a muscovite.
The ejection rate of FP against235Uatom in unit weight fromUmetals was evaluated to about 2.6 times higher value compared toU-Alalloys. This result was attributed to the difference of fission fragment ranges in these materials, which have been reported previously by two works.
From the amounts of uranium and the total number of fission fragments on the collector, the uranium atoms knocked out by one fragment (applied thermal neutron fluence: 8.42×1016cm-2) were calculated to 0.28 and 233 forU-Alalloys andUmetals, respectively. The great difference between two materials implies that aluminium inU-Alalloys plays a very important role to retard the ejection of uranium atoms from the surface.
