Check out Nuclear Instruments and Methods in Physics Research A, Vol. 656, Issue 1, 11 Nov 2011 pg. 92-95. It is a great read.
I've been working on making a coordinate invariant finite difference solver for the general Helmholtz equation so I can solve neutron transport coupled with heat and mass transport. I can do something similar in COMSOL, but I only figured out how to do one group diffusion.
Also been spending a little amount of time on studying the boiling of water in a closed environment. Yay Mondays!