Andrews Space conducted research on improving the original Orion concept, receiving funding under NASA's SBIR program and from the Department of Energy. The concept - termed Mini-MagOrion (MMO) - reduces the size of the original Orion concept through the use of magnetic implosion technology. At the heart of the Mini-MagOrion concept is the idea of compressing initially subcritical fission assemblies by use of an imploding Z-pinch. This enables lower yield values, external triggering of the fission reaction, and reduces the severity of the environment in which the engine has to operate.
Maybe the rumors about Orion's death have been greatly exaggerated?!?