My old typography teacher--who sometimes has no idea what he's talking about--told a wacky story about the inventor of Mr. Coffee building a suburban neighborhood with a nuclear reactor buried underneath in order to gift the neighborhood with free electricity unconnected to the main power grid, got away with it for years, until an inspector noticed something fishy was going on and the reactor was carefully decommissioned. I assumed this was true for years but now can't find anything about it in Google searches. Wikipedia says Mr. Coffee was invented by two guys, not one, and neither of their articles say anthing about a suburban development with a nuclear reactor, which one would think would be highly notable. I'm starting to wonder if one of my teacher's friends made a joke based on Mr. Fusion from Back to the Future and then my teacher misunderstood. Is there any truth to this story?
This sounds like confusing the "Mr. Fusion" from Back to the Future II with the real life story (20 years ago this year!) of the "nuclear boyscout" as documented in this contemporary Harper's article:
https://harpers.org/archive/1998/11/the-radioactive-boy-scout/
Some smoke detectors use a small amount of radioactive material. The particles it emits hit a detector plate but the particles can be blocked by smoke. This is one reason why old detectors need to be replaced and start beeping more frequently:
" To obtain americium-241, David contacted smoke-detector companies and claimed that he needed a large number of the devices for a school project. One company agreed to sell him about a hundred broken detectors for a dollar apiece. "