The Associated Press
The undated diagram that was given to the AP by officials of a country critical of Iran's atomic program allegedly calculating the explosive force of a nuclear weapon. The diagram shows a bell curve and has variables of time in micro-seconds and power and energy, both in kilotons, the traditional measurement of the energy output, and hence the destructive power of nuclear weapons. The Farsi writing at the bottom translates "changes in output and in energy released as a function of time through power pulse"

VIENNA — A leaked diagram suggesting that Iran is pursuing a nuclear weapon is scientifically flawed, diplomats working with the U.N. nuclear agency conceded Friday. However, they insisted that it still supports suspicions that Tehran is trying to build a bomb, especially when combined with other documents that remain secret.

The Associated Press reported Tuesday, citing the document leaked by officials from a country critical of Iran's atomic program, that it indicated that Iranian scientists had run computer simulations for a nuclear weapon that would produce more than triple the explosive force of the World War II bomb that destroyed Hiroshima.

The diagram showed a yield of 50 kilotons. But subsequent criticism of the AP's report showed that result was widely inaccurate. Instead, the yield of the hypothetical weapon was much higher and hugely greater than any bomb ever produced — meaning it was next to impossible that Iran was contemplating such a weapon.

Nuclear scientists Yousaf Butt and Ferenc Dalnoki-Veress, writing on the Web site of the Bulletin of Atomic Scientists, sharply criticized the AP's report and described it as containing a "massive error," adding that it was "either slipshod analysis or an amateurish hoax." They said the "level of scientific sophistication" to produce the diagram "corresponds to that typically found in graduate or advanced undergraduate-level nuclear physics courses."