On 26 September 1986, in Vienna, a special session of the IAEA General Conference adopts and opens for signature the Convention on Early Notification of a Nuclear Accident — the direct legal response to the April 1986 Chernobyl disaster.

Parties undertake to notify promptly the IAEA and states that may be affected of any accident under their jurisdiction involving a significant transboundary radioactive release: time, location, nature and relevant data. The depositary is the IAEA Director General.

Entry into force: 27 October 1986, thirty days after the third consent. The USSR and the Ukrainian SSR signed quickly. Over 120 parties. The text appears as INFCIRC/335.

The same session also adopted the Convention on Assistance in the Case of a Nuclear Accident.

For international nuclear safety, 26 September 1986 marks the Vienna signature.

The document is available on the IAEA website.

The Early Notification Convention of 26 September 1986 remains the post-Chernobyl transboundary-alert milestone.

Image: Vienna / IAEA; Wikimedia Commons. Cropped to 16:9.

Source consulted: Convention on Early Notification of a Nuclear Accident. Treaty text: IAEA — INFCIRC/335.