On April 2, Ambassador Barbour presented to Ben-Gurion our request for semi-annual, full-access United States visits to Dimona to begin in May. On May 19, the President wrote to the Prime Minister to stress the importance we attach to this issue. On May 27, Ben-Gurion replied, agreeing to annual visits, "such as have already taken place", beginning late this year or early in 1964. He referred to this as the "start-up" time of the reactor.
The several branches of the scientific intelligence community (AEC, ACDA, CIA) agree that the Prime Minister's terms fail to meet our minimum requirements. A reactor of this size would at the optimum be discharged every two years if devoted to research, but at approximately six months intervals if the object was to produce a maximum of irradiated fuel for separation into weapons grade plutonium. For a reactor of this size, the IAEA minimum inspection systems calls for two inspections yearly, with far more complete controls than Israel is prepared to allow us. A visit before the reactor goes critical is essential because a more detailed observation of its structure is then possible than after its operation renders certain portions inaccessible.
The several agencies agree that we could be reasonably sure of the use to which the Dimona facility is put, if:
1. There is a June or July 1963 visit.
2. There is a June 1964 visit.
3. Thereafter, visits occur every six months.
4. Our scientists have access to all areas of the site and any part of the complex such as fuel fabrication facilities or plutonium separation plant which might be located elsewhere.
5. Scientists have sufficient time at the site for a truly thorough examination.
This schedule partially meets Ben-Gurion's once-a-year stipulation. We support it because we believe that politically it may be found acceptable. However, it was accepted with some reluctance by our scientists, who would prefer a semi-annual scheduling from the outset and who are also most insistent on the need for thoroughness covered in points 4 and 5.
A proposed further message from the President to Prime Minister Ben-Gurion is enclosed. The proposed message has been approved by the Secretary.
Sources: Foreign Relations of the United States, 1961-1963: Near East, 1962-1963, V. XVIII.