jan 1, 2004 - 2004
January 10 - U.S. Group to Visit North Korea, tours Yongbyon, the probable location of the plant that is reprocessing spent nuclear fuel rods into plutonium.
January 13 - Libya ratifies the Comprehensive Test Ban Treaty.
January 27 - Pakistani investigators have concluded that at least two of the country's top nuclear scientists -- including Abdul Qadeer Khan, considered the father of Pakistan's nuclear bomb -- provided unauthorized technical assistance to Iran's nuclear weapons program in the late 1980s.
January 31 - Pakistan fires A. Q. Khan, the founder of their nuclear program; he is later pardoned by the Pakistani President.
February 15 - Drawings of a nuclear warhead that Libya surrendered as part of its decision to renounce weapons of mass destruction are discovered to be of 1960s Chinese design, but likely came from Pakistan.
February 20 - The International Atomic Energy Agency has said Libya managed to produce a small amount of plutonium using technology acquired on the black market. The report does not specify the amount.
February 25-28 - Six-party talks aimed at ending the standoff over North Korea's suspected nuclear weapons program take place in China.
March 10 - Libya to allow the IAEA to perform unannounced inspections of atomic facilities.
March 29 - Pakistan rejects a request to allow the International Atomic Energy Agency to inspect its nuclear facilities.
April 2 - International Atomic Energy Agency (IAEA) has found traces of bomb-grade uranium in Iran at sites other than the two already named.
June 22 - India and Pakistan set up a nuclear 'hotline'.
June 23 - Talks resume with North Korea over its suspected nuclear weapons program.
September 2 - South Korea reveals that it had secretly conducted an experiment more than 20 years ago with traces of plutonium.
November 28 - Iran pledges to suspend all activities related to plutonium reprocessing and the enrichment of uranium in a deal with the European Union. Iran's nuclear program has been the focus of much international pressure.
Added to timeline:
atomic and nuclear physics