Federation of American Scientists
Israel has not confirmed that it has nuclear weapons and officially maintains that it will not be the first country to introduce nuclear weapons into the Middle East. Yet the existence of Israeli nuclear weapons is a "public secret" by now due to the declassification of large numbers of formerly highly classified US government documents which show that the United States by 1975 was convinced that Israel had nuclear weapons.
Israel began actively investigating the nuclear option from its earliest days. In 1949, HEMED GIMMEL a special unit of the IDF’s Science Corps, began a two-year geological survey of the Negev desert with an eye toward the discovery of uranium reserves. Although no significant sources of uranium were found, recoverable amounts were located in phosphate deposits.
The program took another step forward with the creation of the Israel Atomic Energy Commission (IAEC) in 1952. Its chairman, Ernst David Bergmann, had long advocated an Israeli bomb as the best way to ensure "that we shall never again be led as lambs to the slaughter." Bergmann was also head of the Ministry of Defense’s Research and Infrastructure Division (known by its Hebrew acronym, EMET), which had taken over the HEMED research centers (HEMED GIMMEL among them, now renamed Machon 4) as part of a reorganization. Under Bergmann, the line between the IAEC and EMET blurred to the point that Machon 4 functioned essentially as the chief laboratory for the IAEC. By 1953, Machon 4 had not only perfected a process for extracting the uranium found in the Negev, but had also developed a new method of producing heavy water, providing Israel with an indigenous capability to produce some of the most important nuclear materials.
For reactor design and construction, Israel sought the assistance of France. Nuclear cooperation between the two nations dates back as far as early 1950’s, when construction began on France’s 40MWt heavy water reactor and a chemical reprocessing plant at Marcoule. France was a natural partner for Israel and both governments saw an independent nuclear option as a means by which they could maintain a degree of autonomy in the bipolar environment of the cold war.
In the fall of 1956, France agreed to provide Israel with an 18 MWt research reactor. However, the onset of the Suez Crisis a few weeks later changed the situation dramatically. Following Egypt’s closure of the Suez Canal in July, France and Britain had agreed with Israel that the latter should provoke a war with Egypt to provide the European nations with the pretext to send in their troops as peacekeepers to occupy and reopen the canal zone. In the wake of the Suez Crisis, the Soviet Union made a thinly veiled threat against the three nations. This episode not only enhanced the Israeli view that an independent nuclear capability was needed to prevent reliance on potentially unreliable allies, but also led to a sense of debt among French leaders that they had failed to fulfill commitments made to a partner. French premier Guy Mollet is even quoted as saying privately that France "owed" the bomb to Israel.
On 3 October 1957, France and Israel signed a revised agreement calling for France to build a 24 MWt reactor (although the cooling systems and waste facilities were designed to handle three times that power) and, in protocols that were not committed to paper, a chemical reprocessing plant. This complex was constructed in secret, and outside the IAEA inspection regime, by French and Israeli technicians at Dimona, in the Negev desert under the leadership of Col. Manes Pratt of the IDF Ordinance Corps.
Both the scale of the project and the secrecy involved made the construction of Dimona a massive undertaking. A new intelligence agency, the Office of Science Liasons,(LEKEM) was created to provide security and intelligence for the project. At the height construction, some 1,500 Israelis some French workers were employed building Dimona. To maintain secrecy, French customs officials were told that the largest of the reactor components, such as the reactor tank, were part of a desalinization plant bound for Latin America. In addition, after buying heavy water from Norway on the condition that it not be transferred to a third country, the French Air Force secretly flew as much as four tons of the substance to Israel.
Trouble arose in May 1960, when France began to pressure Israel to make the project public and to submit to international inspections of the site, threatening to withhold the reactor fuel unless they did. President de Gaulle was concerned that the inevitable scandal following any revelations about French assistance with the project, especially the chemical reprocessing plant, would have negative repercussions for France’s international position, already on shaky ground because of its war in Algeria.
At a subsequent meeting with Ben-Gurion, de Gaulle offered to sell Israel fighter aircraft in exchange for stopping work on the reprocessing plant, and came away from the meeting convinced that the matter was closed. It was not. Over the next few months, Israel worked out a compromise. France would supply the uranium and components already placed on order and would not insist on international inspections. In return, Israel would assure France that they had no intention of making atomic weapons, would not reprocess any plutonium, and would reveal the existence of the reactor, which would be completed without French assistance. In reality, not much changed - French contractors finished work on the reactor and reprocessing plant, uranium fuel was delivered and the reactor went critical in 1964.
The United States first became aware of Dimona’s existence after U-2 overflights in 1958 captured the facility’s construction, but it was not identified as a nuclear site until two years later. The complex was variously explained as a textile plant, an agricultural station, and a metallurgical research facility, until David Ben-Gurion stated in December 1960 that Dimona complex was a nuclear research center built for "peaceful purposes."
There followed two decades in which the United States, through a combination of benign neglect, erroneous analysis, and successful Israeli deception, failed to discern first the details of Israel’s nuclear program. As early as 8 December 1960, the CIA issued a report outlining Dimona’s implications for nuclear proliferation, and the CIA station in Tel Aviv had determined by the mid-1960s that the Israeli nuclear weapons program was an established and irreversible fact.
United States inspectors visited Dimona seven times during the 1960s, but they were unable to obtain an accurate picture of the activities carried out there, largely due to tight Israeli control over the timing and agenda of the visits. The Israelis went so far as to install false control room panels and to brick over elevators and hallways that accessed certain areas of the facility. The inspectors were able to report that there was no clear scientific research or civilian nuclear power program justifying such a large reactor - circumstantial evidence of the Israeli bomb program - but found no evidence of "weapons related activities" such as the existence of a plutonium reprocessing plant.
Although the United States government did not encourage or approve of the Israeli nuclear program, it also did nothing to stop it. Walworth Barbour, US ambassador to Israel from 1961-73, the bomb program’s crucial years, primarily saw his job as being to insulate the President from facts which might compel him to act on the nuclear issue, alledgedly saying at one point that "The President did not send me there to give him problems. He does not want to be told any bad news." After the 1967 war, Barbour even put a stop to military attachés’ intelligence collection efforts around Dimona. Even when Barbour did authorize forwarding information, as he did in 1966 when embassy staff learned that Israel was beginning to put nuclear warheads in missiles, the message seemed to disappear into the bureaucracy and was never acted upon.
Nuclear Weapons Production
In early 1968, the CIA issued a report concluding that Israel had successfully started production of nuclear weapons. This estimate, however, was based on an informal conversation between Carl Duckett, head of the CIA’s Office of Science and Technology, and Edward Teller, father of the hydrogen bomb. Teller said that, based on conversations with friends in the Israeli scientific and defense establishment, he had concluded that Israel was capable of building the bomb, and that the CIA should not wait for an Israeli test to make a final assessment because that test would never be carried out.
CIA estimates of the Israeli arsenal’s size did not improve with time. In 1974, Duckett estimated that Israel had between ten and twenty nuclear weapons. The upper bound was derived from CIA speculation regarding the number of possible Israeli targets, and not from any specific intelligence. Because this target list was presumed to be relatively static, this remained the official American estimate until the early 1980s.
The actual size and composition of Israel’s nuclear stockpile is uncertain and the subject of many - often conflicting - estimates and reports. It is widely reported that Israel had two bombs in 1967, and that Prime Minister Eshkol ordered them armed in Israel’s first nuclear alert during the Six-Day War. It is also reported that, fearing defeat in the October 1973 Yom Kippur War, the Israelis assembled 13 twenty-kiloton atomic bombs.
Israel could potentially have produced a few dozen nuclear warheads in the period 1970-1980, and is thought to have produced sufficient fissile material to build 100 to 200 warheads by the mid-1990s. In 1986 descriptions and photographs of Israeli nuclear warheads were published in the London Sunday Times of a purported underground bomb factory at the Dimona nuclear reactor. The photographs were taken by Mordechai Vanunu, a dismissed Israeli nuclear technician. His information led some experts to conclude that Israel had a stockpile of 100 to 200 nuclear devices at that time.
By the late 1990s the U.S. Intelligence Community estimated that Israel possessed between 75-130 weapons, based on production estimates. The stockpile would certainly include warheads for mobile Jericho-1 and Jericho-2 missiles, as well as bombs for Israeli aircraft, and may include other tactical nuclear weapons of various types. Some published estimates even claimed that Israel might have as many as 400 nuclear weapons by the late 1990s. We believe these numbers are exaggerated, and that Israel’s nuclear weapons inventory may include less than 100 nuclear weapons. Stockpiled plutonium could be used to build additional weapons if so decided.
The Dimona nuclear reactor is the source of plutonium for Israeli nuclear weapons. The number of nuclear weapons that could have been produced by Israel has generally been estimated on the basis of assumptions about the power level of this reactor, combined with estimates for the number of delivery vehicles (aircraft, missiles) assigned a nuclear mission.
Information made public in 1986 by Mordechai Vanunu indicated that at that time, weapons grade plutonium was being produced at a rate of about 40 kilograms annually. If this figure corresponded with the steady-state capacity of the entire Dimona facility, analysts suggested that the reactor might have a power level of at least 150 megawatts, about twice the power level at which is was believed to be operating around 1970. To accommodate this higher power level, analysts had suggested that Israel had constructed an enlarged cooling system. An alternative interpretation of the information supplied by Vanunu was that the reactor’s power level had remained at about 75 megawatts, and that the production rate of plutonium in the early 1980s reflected a backlog of previously generated material.
The constraints on the size of Israel’s stockpile include several potential variables, several of which are generic to any nuclear weapons program. The Dimona reactor may have operated an average of between 200 and 300 days annually, and produced approximately 0.9 to 1.0 grams of plutonium for each thermal megawatt day. Israel may have use between 4 and 5 kilograms of plutonium per weapon [5 kilograms is a conservative estimate, and Vanunu reported that Israeli weapons used 4 kg].
The key variable that is specific to Israel is the power level of the reactor, which is reported to be at least 75 MWt and possibly as high as 200 MWt. New high-resolution satellite imagery provides important insight this matter. The imagery of the Dimona nuclear reactor was acquired by the Public Eye Project of the Federation of American Scientists from Space Imaging Corporation’s IKONOS satellite. The cooling towers associated with the Dimona reactor are clearly visible and identifiable in satellite imagery. Comparison of recently acquired commercial IKONOS imagery with declassified American CORONA reconnaissance satellite imagery indicates that no new cooling towers were constructed in the years between 1971 and 2000. This strongly suggests that the reactor’s power level has not been increased significantly during this period. This would suggest an annual production rate of plutonium of about 20 kilograms.
Based on plausible upper and lower bounds of the operating practices at the reactor, Israel could have thus produced enough plutonium for at least 100 nuclear weapons, but probably not significantly more than 200 weapons.
Some type of non-nuclear test, perhaps a zero yield or implosion test, occurred on 2 November 1966 [possibly at Al-Naqab in the Negev]. There is no evidence that Israel has ever carried out a nuclear test, although many observers speculated that a suspected nuclear explosion in the southern Indian Ocean in 1979 was a joint South African-Israeli test.