The story itself is true, but it suffers from the Typical Anti-Nuclear Media Hysteria.
Fact #1 is this: The materials he collected were incapable of fission. All he did was concentrate a fair quantity of dangerous shit in a small area and overexpose himself.
Fact #2: The media hyped this up so "bad" that what would have been a simple cleanup procedure around his workshop/shed turned into a massive multi-million dollar undertaking with people afraid to go home because lawyers insist it's too dangerous to do so. Same thing happened to Diaz Chemical here in Rochester.
*shrug* A little research and an open mind will allow you to see the anti-nuclear hysteria for what it is. The media decided (at the oil companies prompting) that anything nuclear is bad, and they deliberately go out of their way to misrepresent facts.
A few years ago I was a "media relations adviser" for a nuclear power plant. My job was to present the facts to the media and then recheck copy before it made it to TV or the newspaper. The media is so convinced that you are lying to them they will go out of their way to present their "facts" and discredit anything you tell them. Very stressful job, glad I'm not doing that shit anymore.
Science can sum up the universe like this:
REALITY = STUFF HAPPENS
Religion sums it up like this: REALTY = STUFF HAPPENS BECAUSE GOD MADE IT HAPPEN UNLESS WE DISAGREE THAN SATAN DID IT.