“While Disneyland, Walt Disney World and the Super Bowl are all official no-fly zones in the terror age, the Indian Point nuclear power plant – 35 miles north of midtown Manhattan in Buchanan, N.Y. – is not. This despite the fact that hijacked American Airlines Flight 11 soared over Indian Point on 9/11 before crashing into the north tower of the World Trade Center.

“If Indian Point is ever attacked, some 20 million people within a 50-mile radius could be affected,” says Rory Kennedy, director of “Indian Point: Imagining the Unimaginable,” which debuts on HBO Thursday at 8 p.m.

In this scary documentary, Kennedy – unquestioned and undeterred – hovers above the nuclear plant in a helicopter with her environmental activist brother Robert Kennedy Jr.

“My feeling is that the electricity we generate out of this plant is just not worth the ongoing risks,” says Ms. Kennedy, whose previous documentaries include 1999’s “American Hollow.” “By their own admission the private security force that Entergy Corp. [the New Orleans-based owner of the plant] has hired to protect Indian Point from an air, ground or boat attack is inadequate.”

The film presents the 40-year-old plant, which stores thousands of gallons of radioactive spent fuel, as a time bomb waiting to go off. Local police officials say there is no effective evacuation plan in the event of an attack or accident.

“I [was living] 20 blocks north of the World Trade Center on Sept. 11,” says Kennedy, who now lives in Brooklyn. “After the initial sadness you wondered what would be the next target. I heard my brother Bobby speak quite passionately at a forum for Riverkeeper, an environmental organization, about the dangers of Indian Point. And I was really frightened and thought it was deserving of a documentary.”

In her film Kennedy interviews federal bureaucrats, nuclear experts, environmental activists and politicians. But an Entergy spokesman offers no comment. Gov. Pataki and Mayor Bloomberg decline interviews. So do U.S. Sens. Charles Schumer and Hillary Clinton.

Pataki and Bloomberg are local pols. But this is a national security issue screaming for federal attention. While U.S. troops guard oil pipelines in Iraq, we have rent-a-cops protecting a vulnerable nuclear plant an hour’s drive from Ground Zero.

Asked why she thinks Schumer and Clinton declined to speak to her, Kennedy says, “I think that they are probably ashamed that they haven’t done enough. That it’s clearly an issue Schumer and Clinton should be more proactive on. That it’s in the public interest for them to take an active stance on this issue, and that they haven’t done that. So they don’t have a record to defend.”

Blake Zeff, a Schumer spokesman says, “Chuck Schumer is a leading advocate for increasing safety at Indian Point and has been a clear and outspoken advocate for several years. Unfortunately, we cannot accommodate every documentary that comes our way.”

“Senator Clinton has a strong record on addressing safety and security issues related to Indian Point and is committed to continue to work closely with the community to raise awareness,” says Jennifer Hanley, a Clinton spokeswoman.

“Senator Clinton respects Rory Kennedy and values her work as a documentary filmmaker. It was not possible for her to participate in this project.”

“Are we doing everything we can to protect Indian Point?” asks Kennedy. “Absolutely not.”

Immediately following “Indian Point,” HBO will air Maryann DeLeo’s Oscar-winning documentary short, “Chernobyl Heart,” which examines the horrifying medical aftermath of the 1986 explosion at the Ukrainian nuclear power plant.

See these films back to back, and you will be afraid. Very afraid.”