If you read the wiki or watch the defcon video it did get hot
His property was designated superfund cleanup site, all taken to Utah nuclear waste disposal. 5 block radius was evacuated.
He had over safe limits of radioactivity readings 5 blocks away. Geiger counters were saturated off charts on the property.
The breeder was left running for days and the levels were insane
Updated story from UK
On June 26 1996 Davidâ(TM)s boyish experiment shut down a neighborhood of 40,000 residents.
Photos of the hazmat suits and barrels of radioactive material
How he got thorium
He bought $1,000 worth of lithium batteries, sawed them down, extracted the element, put it with thorium dioxide in a tin foil ball, cooked it over his Bunsen burner and the result was purified thorium, to 170 times the amount that needs NCR licensing.
He made a list of sources of such materials: Americium-241 could be found in smoke detectors, radium 226 could be found in antique luminous clocks, uranium 238 and quantities of uranium 235 existed in black ore called pitchblende (he has a polaroid picture of glowing pitchblende stuck to his refrigerator today) and thorium 232 is in Coleman style gas lanterns.