The old Soviet Union was not what one would term a paragon of security, the KGB and GRU notwithstanding. Not at least when it came to its nuclear arsenal. When the Soviet Union fell apart there was a flurry of activity to secure its nuclear arsenal, or at least to ascertain who had what and where. Yeltsin, in one of his fleeting moments of sobriety, ordered a full inventory of the nuclear arsenal as one of his first acts as President.
Now, in theory, the old Soviet nuclear arsenal was inspected twice a year, but there was apparently no reliable count on warheads, etc. There was also no hands-on inspection of things like SCUD missile warheads to ensure that the device in stock had not actually been replaced by an identical-appearing training dummy. (Real nuclear warheads were rarely mated up to their launch systems on military field exercises and the arming keys were under the control of KGB officers.) Bear in mind here that a SCUD warhead can be carried by three men. The arsenal also included such items as nuclear artillery shells, land mines, torpedo warheads, etc, all of which could be lifted by one man. It also included a particular item that was classified as an “atomic demolition device,” technically an engineering tool, to get it around the limitations imposed by SALT II. These devices, known as “CHEMODAN,” can be carried by one man. They are, for all intents and purposes, the fabled “suitcase nuke” with an estimated yield of between 2 to 3 kilotons.
Back in 1996, Yeltsin’s Secretary of the National Security Council was General Alexandr Lebed, who had unrestricted access to all of Russia’s (and the old Soviet Union’s) defense secrets. He ordered a special inventory of the “chemodan” knowing that there were supposed to be 132. There weren’t. An extensive, and I assume increasingly panicked search turned up only 48.
To this day, there are 84 “chemodan” suitcase nukes still missing. No one knows where they are or who has them.