Radioactive waste is read as something toxic from the past that lingers and cannot simply be thrown away. Dream books see it as unresolved matters that need careful handling, not as a literal threat.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.