Russia says Ukraine is preparing a “dirty bomb.” Is it true, and what does it mean?

On October 23, Russian Defense Minister Sergei Shoigu claimed that Ukraine was preparing to use a “dirty bomb”—a weapon that uses conventional explosives laced with radioactive material. In a series of phone calls to his counterparts in France, Turkey, the United Kingdom, and the United States, Shoigu said that he was “concerned about possible provocations by Kyiv involving the use of a dirty bomb.”