The chemical consequences of thermal neutron capture in alkali selenates—II

Influence of Cationic Dopants on the Thermal Annealing of Reactor-Irradiated K2SeO4

“…However, a detailed examination of the experimental data, such as by differenciation of the annealing isochronals, shows that more than one step, very possible two, are introduced by the impurities in the spectra, although with very close activation energies. This fact may certainly find an explanation in the existence of two different sites for the ii) as discussed in [15,18] …”

“…But relation (1) includes a further physical meaning: the experimental spectrum relates to the donor species. It is not excluded that some of the recoil species also pertain to the species D, such as may be the case for SeOj in irradiated K 2 Se0 4 [15,18].…”

Separation of 239U(IV) and 239U(VI) by HPLC

“…Stability constants of oxalato complexes of U(VI) [20] UO¡ + + C 2 0|-^U0 2 C 2 0 4 K.! = (430 ± 2.5) χ ΙΟ 2 M" 1 υθΓ + 2C 2 0 4~ ^±U0 2 (C 2 0 4 )r K2 = (4.9 ± 0.39) χ 10® M" 2 UOi + + 3C 2 0r^±U0 2 (C 2 0 4 )r K 3 = (1 ± 0.1) χ 10 12 M" 3 Temperature (293 ± 0.2)K, ionic strength adjusted to 1.0 Very low retentions are a common feature of neutron irradiated ammonium salts [21,22], This peculiarity very probably arises from the presence of reducing, hole scavenging, radiolytic debris in the solid as was experimentally evidenced in E.P.R. [23,24], There are, however, examples where the retention is not so low, such as in neutron irradiated ammonium Chromate, where it is at about 20% [25].…”

Chemical Effects of the 238U(n,y)239U Reaction and of the 239U→β– 239Np Decay in Solid Uranium Compounds

“…Thus, its reducing action is increased comparatively with that of other compounds. The absence of reduced form, 239 U(IV), in the case of the ammonium diuranate can only be explained by the absence of local radiolytic decomposition after the (n,y) reaction, as the presence of ammonium ions should result in the formation of highly reducing radiolytic products, such as hydrazine [28], In the case of formate, the formation of two reducing agents: H' and 'COJ concurs to produce a highly reducing medium.…”