Hi there, always more to be said here but you may be interested in these older answers from u/restricteddata and u/yodatsracist:
https://www.reddit.com/r/AskHistorians/comments/5idd3e/when_and_how_did_israel_obtain_nuclear_weapons/
and
https://www.reddit.com/r/AskHistorians/comments/1c0nox/does_the_size_of_israels_nuclear_stockpile/