Novel Model Illustrates The Finer Details Of Nuclear Fission (phys.org)

mdsolar quotes a report from Phys.Org: For nearly 80 years, nuclear fission has awaited a description within a microscopic framework. In the first study of its kind, scientists collaborating from the University of Washington, Warsaw University of Technology (Poland), Pacific Northwest National Laboratory, and Los Alamos National Laboratory, developed a novel model to take a more intricate look at what happens during the last stages of the fission process. Using the model, they determined that fission fragments remain connected far longer than expected before the daughter nuclei split apart. Moreover, they noted the predicted kinetic energy agreed with results from experimental observations. This discovery indicates that complex calculations of real-time fission dynamics without physical restrictions are feasible and opens a pathway to a theoretical microscopic framework with abundant predictive power.

Comments

How much computation you ask?

[mdsolar]

The researchers extended the density functional theory (DFT) modeling method designed for electronic structure systems to strongly interacting many-fermion systems and real-time dynamics, creating a time-dependent superfluid local density approximation (TDSLDA). For the study reported, evaluating the theory amounted to solving 56,000 complex coupled nonlinear, time-dependent, three-dimensional partial differential equations for a 240Pu nucleus using a highly efficient parallelized graphic processing unit (GPU) code. The calculations required 1760 GPUs and 550 minutes total wall time on Titan, a Cray XK7 supercomputer located at the Oak Ridge Leadership Computing Facility (OLCF).

Re:How much computation you ask?

[caffeinated_bunsen]

So what are the implications for reactor design, physicists?

Probably not much. There's so much empirical data about the behavior of fission in reactor-like conditions that, even without a deep understanding of why things happen that way, we pretty much know what happens. That's almost certainly why they simulated the reaction they did -- we have tons of data about it already, so you can tell if the model's good.

Some slight refinements might show up eventually, but the impact of a model like this on reactors will be small.

Most nuclear physicists aren't researching fission reactors, though. The ones pushing the boundaries of the field, coaxing colliders into producing heavier nuclei, investigating weird excited states, and such, are the ones who will really notice this.