Advanced Modelling of 238U(n,f) in a Fast Reactor Application

Fast neutron reactors, as a possible future solution on energy demand of human society, based on fission process of $^{238}$U, request new and reliable nuclear data necessary for new generation reactors design. Fission process induced by fast neutrons on $^{238}$U was investigated. Fission observables like cross sections and their uncertainties, fission fragment mass distribution, prompt neutrons emission, isomer ratios and other parameters were obtained by using Talys computer code or programs realized by authors. Then the production of isotopes like $^{135,133}$Xe, $^{99}$Mo, $^{131}$I, $^{89}$Y as well as yields of fissile nuclei were evaluated. Obtained theoretical evaluations are compared with existing experimental data

Astrophysical production of 146Sm^{146} \mathrm{Sm} in nuclear p - processes

The large time of life of $^{146} \mathrm{Sm}$ suggests the possibility to use this p - nuclide as astrophysical chronometer to study the geochemical galactic evolution. Due to the high temperature and large densities of gamma quanta, neutrons and protons in stellar environment $^{146} \mathrm{Sm}$ nucleus can be obtained in (γ,n), (n,2n), (p,2n) processes on $^{146} \mathrm{Sm}$ .The knowledge of corresponding cross sections of gamma rays, neutrons and alpha induced processes is of a great importance for the explanation of ($^{146} \mathrm{Sm}$ /$^{144} \mathrm{Sm}$  ) ratio uncertainties observed on the Earth, meteorites, Moon and other celestial bodies.Cross sections of (γ,n), (n,2n), (α,γ) processes induced by fast gamma rays, neutrons and alphas on $^{147} \mathrm{Sm}$ and $^{142} \mathrm{Nd}$  from threshold up to 25 MeV were evaluated and predicted in the frame of Hauser-Feshbach statistical model by using Talys software and the own computer programs. For each nuclear reaction contribution of direct, compound and pre-equilibrium mechanisms were determined. Theoretical evaluations are compared with existing experimental data. Parameters of optical potential in the incident and emergent channels and of nuclear densities were extracted. Calculated cross sections together with corresponding nuclear data were used in the evaluation of astrophysical rates necessary in the determination of elemental abundances as needed by nuclear astrophysical networks