I'm skeptical about this. It is widely known that Israels nuclear program was assisted mainly by the French and the British, with some fissile material arriving from Argentina and Belgium. At the time (1960s) Israel was ready to produce weapons grade plutonium on an independent basis.
Saying Israel stole that uranium is saying they preferred to steal from a super-power what they could already produce. Possible, but unlikely.
Israel has stolen other nuclear tech from the US, so it doesn't seem that unlikely.
> Richard Kelly Smyth, the President of a company called MILCO, was indicted that same year for smuggling over 800 krytron switches (a component used in nuclear weapons) to Israel without the required US State Department Munitions Export License. Just before trial, and facing a possible 105 years in prison, Richard Kelly Smyth and his wife suddenly disappeared. Sixteen years later they were discovered and arrested while living as fugitives in Malaga, Spain, and extradited back to the United States where he was convicted in the case. The krytrons shipped by Smyth were sent to an Israeli company called Heli-Trading Ltd. owned by notable Israeli movie producer Arnon Milchan.
"Stealing" is different from "smuggling". The switches weren't secret tech in a govt lab, they were export-controlled private-sector tech-for-sale (similar legal status as encryption software)
The dictionary definition of "stealing" (http://dictionary.reference.com/browse/stealing) is "to take (the property of another or others) without permission or right". Israel didn't have permission to take possession of the tech, so seems like the word is applicable.
Saying Israel stole that uranium is saying they preferred to steal from a super-power what they could already produce. Possible, but unlikely.