Is an MRI nuclear

MRI (magnetic resonance imaging) or as it used to be called NMR (nuclear magnetic resonance) has nothing to do with nuclear energy or nuclear radiation. but yes it is nuclear, it has to do with nuclear magnetism.

A strong magnet lines up the magnetic fields of the nuclei in the atoms of your body then a radio pulse flips those magnetic fields and by measuring how long the magnetic fields of nuclei in various parts of your body gyrate and take to settle back in alignment with the external field they can compute a picture.