Advanced theoretical methods and high-performance computers may finally unlock the secrets of nuclear fission, a fundamental nuclear decay that is of great relevance to society. Under this project, we study the phenomenon of spontaneous and induced fission, and heavy-ion fusion using the symmetry-unrestricted nuclear density functional theory (DFT) and its extensions, including time-dependent DFT. From the calculated collective potential and collective mass, obtained within the full adiabatic time-dependent framework, we will calculate lifetimes and fission yields by combining the multidimensional minimization of the collective action, which produces tunneling rates, with stochastic Langevin dynamics to track fission trajectories from the outer turning point down to scission. The resulting data will provide microscopic input for predictive fission cross-section calculations. The predicted properties of fission yields will also be used in modeling of astrophysical rapid-neutron process and in simulations relevant to nuclear fuel cycle. Under this proposal, we shall train one postdoc and two graduate students in the area of low-energy nuclear physics.

The Goals of the Project

  1. Development of effective energy functionals that are appropriate for the description of heavy deformed nuclei. Our goal is to improve the existing energy density functionals to develop an effective interaction that will be used in calculations of fission dynamics. To this end, we use state-of-the-art developed Hartree-Fock (HF) and Hartree-Fock-Bogoliubov (HFB) codes.

  2. Systematic self-consistent calculations of fission and heavy-ion fusion properties of actinide and trans-actinide nuclei using modern density functionals using dynamic approaches based on the WKB approximation coupled to stochastic Langevin dynamics, and time-dependent nuclear density functional theory.

  3. Provide uncertainty quantification to theoretical predictions using linear regression, Bayesian machine learning, and dimensionality reduction

  4. Investigate novel microscopic (non-adiabatic) methods to study the fission and heavy-ion fusion processes.

  5. Develop codes and technology that can be freely used by NNSA researchers and, generally, by the low-energy nuclear physics community.

  6. Train junior scientists and students to apply nuclear many-body techniques to describe low-energy nuclear phenomena.