Israelis have much more than a nuclear reactor at Dimona site.
The Dimona reactor became active (critical) sometime between 1962 and 1964, and with the plutonium produced there, the Israel Defense Forces most likely had their first nuclear weapons ready before the Six-Day War.
When the United States intelligence community discovered the purpose of the site in the early 1960s, the U.S. government requested that Israel agree to international inspections. Israel agreed, but on the condition that inspectors from the U.S., rather than the International Atomic Energy Agency, be used, and that Israel would receive advance notice of all inspections. According to declassified Johnson Administration documents, Israel opened Dimona to U.S. inspection in January 1965.[4]
It has been asserted that because Israel knew the schedule of the inspectors’ visits, it was able to hide the clandestine manufacture of nuclear weapons, thereby deceiving the inspectors, by installing temporary false walls and other devices before each inspection.[18] The inspectors eventually informed the U.S. government that their inspections were useless, due to Israeli restrictions on what areas of the facility they could inspect. By 1969 the U.S. believed that Israel might have a nuclear weapon,[19] and terminated inspections that year.
The full-scale production of nuclear warheads is believed to have commenced by 1966, with the Israel Defense Forces believed to be in possession of up to 13 operational nuclear warheads by 1967.
In 1986, Mordechai Vanunu, a former technician at Dimona, fled to the United Kingdom and revealed to the media details of Israel’s nuclear weapons program. He went on to explain the purposes of each building, also revealing a top-secret underground facility directly below the installation.
In April 2016 the U.S. National Security Archive declassified numerous documents from 1960 to 1970, which detail American intelligence opinions relating to Israel’s attempts to obfuscate the purpose and details of its nuclear program. American officials involved in discussions with then Prime Minister David Ben-Gurion and other Israeli officials believed the country was providing “untruthful cover” about intentions to build nuclear weapons.