GWEN IFILL: Next, questions about the safety and future of nuclear energy in the wake of the Fukushima reactor disaster in Japan.
NewsHour science correspondent Miles O'Brien traveled to three continents to find the answers. Here in the United States, he looked at the Indian Point Power Plant in Buchanan, New York. One of the reactors there was shut down last week for repairs, the 18th unplanned shutdown in five years.
Here's a portion of Miles' piece.
MILES O'BRIEN: A Fukushima-scale accident here, less than 50 miles from the lower tip of Manhattan, would likely mark the end of the U.S. nuclear industry. Seventeen million people live within 50 miles of this plant.
And that's one reason plant operator Entergy's application for a 20-year renewal is proving so controversial.
The company says it spent a billion dollars on upgrades and that an accident of the scale of Fukushima couldn't happen here.
JOE POLLOCK, Indian Point Energy Center: The problem in Japan was, they weren't able to cool the reactors. We have six sources of off-site power. We have three emergency diesel generators on both units. I have two more redundant emergency diesel generators. Either one is capable of safely shutting down the unit. They're located at four different elevations, four different areas of the plant. Some are in bunkers you were in. One is elevated at least 40 feet above where the water is.
MILES O'BRIEN: This is a contentious license renewal, the most contentious I think we can agree on, right? Why?
JOE POLLOCK: Well, we're in a metropolitan area. When the plant was built back in the '60s, because unit one was actually commercial in 1961, there was people that didn't want it here then.
But we are a valuable asset to the community here in many ways, in the air quality. We're a low-cost provider of electricity. Therefore, we hold the price of electricity down in the area. And, in fact, if you look at our life extension, if we operated 20 more years, just the union labor would earn over $1.3 billion in earnings at today's salary.
MILES O'BRIEN: The plant has its passionate critics.
LYNN SYKES, Columbia University: We have had some earthquakes in the Eastern and Central U.S.
MILES O'BRIEN: Lynn Sykes, a Columbia University geologist, has spent years arguing that the Indian Point Plant is not fully prepared for earthquakes. Two seismic fault zones intersect one mile north of the plant.
All right, so the Ramapo Fault, which you discovered. Where is Indian Point?
LYNN SYKES: Indian Point is right here.
MILES O'BRIEN: Right on the fault.
When they were designing Indian Point, this was unknown.
LYNN SYKES: This was unknown. The original design for Indian Point one barely mentions earthquakes, except to say that this region is quiet compared to Alaska and California and Japan, which is true.
MILES O'BRIEN: If they were designing the plant today, says Sykes, the NRC would certainly take into account the newly discovered seismic data.
Let's start with the earthquake and paint the series of sequences that worry you that could lead to a loss of water and lead to that release of radioactive material.
LYNN SYKES: Right. So, one would be if the reactors themselves are damaged by an earthquake that is large enough to crack critical components of that system.
MILES O'BRIEN: That would be a pretty big quake, wouldn't it?
LYNN SYKES: Well, it could be a magnitude 6. If you have an earthquake that is very close to Indian Point, it doesn't take as large an earthquake to cause damage, particularly if it's shallow.
MILES O'BRIEN: And yet you still live here.
LYNN SYKES: I still live here. I live 17 miles from Indian Point.
MILES O'BRIEN: How much concern does that give you?
LYNN SYKES: It gives me a fair amount of concern, and one of the reasons is that Indian Point is closer to more people than any other reactor in the country.
MILES O'BRIEN: Not all experts agree with Lynn Sykes. Other geologists claim the Ramapo Fault is not seismically active, and Entergy's insists Indian Point could handle a magnitude-7 quake.
The fuel that is in there is all the fuel that unit three has ever used in the course of its history?
MAN: Yep, since 1976.
MILES O'BRIEN: So, you're full?
MAN: This pool is basically full. We have an application pending with the NRC. . .
MILES O'BRIEN: Nonetheless, with all this radioactive material on site, Sykes' work raises an important question: If a powerful earthquake triggered a series of unforeseen events, leading to a release of radiation like Fukushima, how would so many people make their way to safety?
GWEN IFILL: "Nuclear Aftershocks" can be seen on PBS' "Frontline" tonight. Check your local listings for times.