A reactor isn’t a catalytic converter. They might get some coolant that’s mildly radioactive. The core would probably kill them if they ever managed to open it. There’s not a button to just open it, it’s only designed to be opened with heavy equipment in drydock.
Dirty bombs are more of a boogie man than a real thing. High grade materials are dangerous to be around without shielding and can fairly easily be tracked. It’s just as likely to kill the makers before they can get a bomb together than be used. Lower grade materials require more to be dangerous, which means less spread with the same explosive, and the bomb has to be pretty big. It’s easier to get a backpack full of explosives into somewhere than a van full of radioactive material, and the backpack will have a bigger radius.





Local appliance dealers likely also have a dude who in a pinch can just carry most appliances where they need to go.