Nuclear Disaster Preparedness Act - Directs the President to issue guidance on the federal response to any nuclear disaster that: (1) may be caused by a natural catastrophe, an accident, or a terrorist or other attack; (2) occurs initially at a nuclear power plant; and (3) disperses radiation off the reactor site and into the surrounding area.

Requires such guidance to:

• designate the single federal agency responsible for coordinating the government's efforts in response to a nuclear disaster (coordinating agency), including making a formal declaration that a nuclear disaster exists;
• identify the circumstances under which such declaration will occur;
• designate the single agency responsible for recommending the evacuation of the area within a 10-mile to 50-mile radius from the nuclear power plant;
• identify the circumstances under which such recommendation will be made;
• designate the single agency responsible for developing plans for, educating the public regarding, and conducting, such evacuation;
• designate the single agency responsible for recommending that evacuees may return following a nuclear disaster;
• identify the circumstances under which such recommendation will be made;
• designate the single agency responsible for conducting cleanup of a nuclear disaster; and
• identify what cleanup standards will apply.