Yes. Only in fantasy land. As Logi above said, nuclear detonation is an extremely precise, controlled process that has very specific conditions to achieve successfully. Even an actual fission bomb only manages to consume a fraction of the radioactive material.

The only thing someone would achieve by denotating a conventional explosive near a reactor or nuclear stockpile is spreading highly radioactive dust around. That does not nor will ever look like uncontrolled nuclear fission, let alone a detonation from a thermonuclear warhead.