Evacuation, temporary shelter and iodine pills are the chief weapons for protecting civilians against nuclear fallout, experts say.

Japan is racing to prevent a nuclear disaster, as explosions rocked overheating reactors after cooling systems at the reactors failed following Friday's quake.

Specialists say the authorities have a several-pronged strategy for shielding civilians if there is an explosive breach of the reactor, as in the April 26, 1986, Chernobyl disaster.