During a June 28, 2012, "Talk at Google", Stanford professor Mark Jacobson made the following claim:
One and a half percent of all nuclear reactors ever built, and there have been about 440, have melted down to some degree.
The slide with this claim appears at the timestamp where the link starts:
A few moments later, in talking through this point, he adds the caveat ("to some degree"), which is not on the slide.
Have 1.5% of all nuclear reactors built as of June 2012 melted down?
This talk takes place over a year after the Fukushima Daiichi nuclear disaster, which basically put a freeze on new reactor construction, so the 440 figure is likely still the same despite the fact that this talk is now seven years old.
