This is the second and updated edition of the report Nuclear Fissile Materials. The first edition of Nuclear Fissile Materials was prepared and published by Bellona’s experts in late 2011. Authors: Alexander Nikitin; Prof. Vladimir Kuznetsov, D.Sc. Eng.; Andrei Zolotkov; Valery Menshchikov, Ph.D. Eng.; Alexei Shchukin, Ph.D. Chem.