The newspaper cited Israeli Defense Minister Moshe Yaalon's warning, in 2013, that Iran is capable of procuring a bomb that combines conventional explosives with radiological material.
A dirty bomb is not considered to be a nuclear weapon or a weapon of mass destruction.
A project dubbed "Red House" also tested the potential of an unexploded dirty bomb, left in a public setting such as a shopping mall, to emit radiological material.
Haaretz cited sources at the nuclear facility as saying that such dispersal of radiological material posed little danger "beyond the psychological effect."
Israel is not a signatory to the Non-Proliferation of Nuclear Weapons Treaty (NPT), to which 191 countries have signed up, entering into force in 1970. The NPT aims to prevent the spread of nuclear weapons while promoting the use of civilian nuclear technology.