Upcoming Release Notes#

New Features#

A new nodal diffusion solver based on the nodal CMFD method with 2-node current calculations has been added. This new solver, called NEM4DiffusionDriver is approximately 10 times faster than the previous NEMDiffusionDriver solver which was based on the method of interface currents. It has an identical interface to the previous solver (with a few added elements), and should work as a drop in replacement. As such, the previous NEMDiffusionDriver has been deprecated. The motivation behind this new solver is not purely the better run time performance, but it is written in such a way that is will be drastically easier to add other nodal methods in the future, such as the Semi-Analytical Nodal Method and the Analytical Nodal Method.
A new finite-difference diffusion solver, based on the new CMFD nodal kernel method above, has been added. This new solver is called FDNodalDiffusionDriver. Currently, there are no plans to deprecate the previous FDDiffusionDriver class, as that solver yields superior performance for finite-difference calculations.
A new Semi-Analytical Nodal Method solver, called SANMDiffusionDriver has been added, based on the new nodal diffusion solver shell. This solver uses a flux expansion based on a quadratic and hyperbolic functions.

There was a bug where copying a DiffusionData instance in Python did not include the LeakageCorrections which may be present. This resulted in the copies not having a LeakageCorrections instance and gave incorrect results in nodal diffusion calculations.