Are nuclear facilities secure?

After 9-11 there was some discussion about safety at nuclear power plants; would a plane crashing into a cooling tower cause a meltdown or not. Opinion was mixed. Some expert evident says, "The risk that planes will crash into nuclear plants and release potentially lethal clouds of radioactivity is significantly higher than official estimates" while the Nuclear Energy Institute (the nuclear energy industry’s policy organization) disagrees, "Structures that house reactor fuel at U.S. nuclear power plants would protect against a release of radiation even if struck by a large commercial jetliner".

Whoever is correct, I suspect this statement from SecurityManagement.com hits the nail on the head, "The United States is woefully unprepared to protect its nuclear power plants from a terrorist attack, a former CIA officer divulged on CNN.com"

Consider this recent story,

Tennessee's Y-12 National Security Complex houses 300 to 400 metric tons of bomb-grade uranium. The Oak Ridge plant, enriched the uranium for the atomic bomb dropped on Hiroshima, Japan, during World War II and continues to be a mainstay of the U.S. nuclear defense program. The Department of Energy has repeatedly claimed that security at the site is robust enough to defend against more than a dozen heavily-armed terrorists with inside knowledge of security procedures.

And yet, last month,

Three peace activists — including an 82-year-old nun — infiltrated the highest-security area of the Y-12 nuclear weapons plant in a predawn protest Saturday, reportedly evading guards and cutting through three or four fences in order to spray-paint messages, hang banners and pour human blood at the site where warhead parts are manufactured and the nation’s stockpile of bomb-grade uranium is stored.

I have to agree with this conclusion from the HuffingtonPost,

When a nuclear weapons facility can't stop infiltration by an octogenarian nun, it's time to reassess its security standards.