[en] Savannah River National Laboratory estimated activities of various radionuclides in vapor phase associated with saltstone. These radionuclides, as well as the estimated activity and concentration of each in the gases phase are listed. Some of the activities are so low they should be considered zero. In particular, activity of the antimony and tin isotopes in the gas phase correspond to less than a molecule of gas per 340 m3 of vapor volume. Equilibrium calculations of the partitioning of each radionuclide between vapor and dissolved phases were done using the Geochemists Workbench (R). The conceptual model used was that 1 curie of each constituent was available to partition between vapor and dissolved phases. The overall assumption is that exposure would come from a single release of the vapor phase from a saltstone vault

[en] We study the emergence of neutron gas effects in the description of nuclei with large neutron excess within the Bardeen-Cooper-Schrieffer approach. We consider Ni and Sn isotopes where, in the literature, these effects have been found. We investigate the role of the single-particle states with positive energy generating the neutron gas, and we find that the contribution of these states is numerically irrelevant for the various observables that we evaluate. (authors)

[en] The reduced M2 transition probabilities 11-/2₁ -> 7+/2₁ in the odd-A isotopes ^109-121Sn are found to reveal a specific behaviour. B(M2) values are calculated in the framework of the quasiparticle-phonon model. The coupling of a quasineutron with the 2⁺, 3^- and 2^- one-phonon core excitation is taken into account. Inclusion of all one-phonon 2^- states up to 24 MeV in the wave functions of the excited states 11-/2₁ and 7+/2₁ reduces the theoretical B(M2) values by 3-4 times as compared to the single particle values. The specific B(M2) dependence on the mass number appears to be due to the pairing effect. (orig.)

No abstract available

[en] Full text: Exotic nuclei beyond the ¹³²Sn double-shell closure are influenced by both the Sn superfluidity and the evolving collectivity only few nucleons away. Toward even more neutron-rich nuclei, especially at intermediate mass number, interplay between single-particle and collective particle-hole excitations compete. In some cases with the extreme addition of neutrons also other effects as the formation of neutron skin [1], stabilization as sub-shell gaps [2], and/or orbital crossings [3] may be expected. The knowledge of nuclear ingredients is especially interesting beyond ¹³²Sn and little is known on how the excitations modes develop with the addition of both protons and neutrons [4-7] and for example systematic prompt and decay lifetime studies can be a very sensitive probe. Recently, we have approached this region of nuclei in several measurements following fission as ²³⁸U on ⁹Be target, within the EURICA project [8-9], n-induced fission on ²³⁵U/²⁴¹Pu targets using prompt-decay spectroscopy within the EXILL/FATIMA campaigns [10-11], as well as in decay spectroscopy at LOHENGRIN. Examples from these studies on several nuclei in the region will be presented together with the possible interpretation of the new data.

[en] A pairing interaction fitted to be applied in nuclei with active particles moving close to the continuum threshold or even immersed in the continuum itself is introduced. It is found that the effects of the nonresonant continuum upon physically meaningful quantities is unimportant. We applied the theory to heavy tin isotopes and good agreement between theory and the very few available experimental data is found

No abstract available

[en] The validity of the diagonal-pairing approximation is studied. It is shown that in the case of volume pairing the relaxation of the diagonal approximation affects the results in an infinitesimal way. A series of calculations in the diagonal approximation is performed for a number of nuclei. The nuclei of the ''magic +- 2 particles'' type, for which the approximation of developed pairing is not valid, are considered separately. The nucleon stability boundaries are studied in the example of the Sn and Pb isotopes

[en] Short communication

[en] A self-consistent theory of finite Fermi systems is developed for superfluid nuclei at nonzero temperatures. Calculations are carried out for a chain of even Sn isotopes. The temperature dependence of the energy gap Δ(T) turns out to be similar to the square-root behavior known from the BCS theory. The critical temperature T_c at which pairing disappears varies from one nucleus to another because of a change in the level structure near the Fermi surface. However, the relation between T_c and Δ(0) proves to be close to that predicted by the BCS theory: T_c = 0.57Δ(0). The self-consistent theory confirms the main result, in which calculations were performed in the approximation of a fixed nuclear mean field: the size of a superfluid nucleus decreases with temperature. 13 refs., 6 figs., 3 tabs