In June, National Geographic sent AP photographer David Guttenfelder into the "exclusion zone" around Japan's Fukushima Daiichi nuclear power plant. The earthquake and tsunami in March had triggered a meltdown at the plant; more than 70,000 residents in the vicinity were evacuated. His images are featured in the December edition.

In November, Guttenfelder visited the nuclear power plant itself and witnessed a striking scene of devastation: twisted and overturned vehicles, crumbling reactor buildings, piles of rubble virtually untouched since the wave struck more than eight months earlier.

On November 12, the grounds of the Fukushima Daiichi nuclear power plant were opened to a small group of media for the first time since March, when the earthquake and tsunami triggered explosions and the reactors melted down. I was the only non-Japanese photographer allowed in.

We had to wear white suits to protect against radiation, a full respirator mask, two pairs of gloves, and plastic booties over our shoes. Officials from the Tokyo Electric Power Co., which runs the plant, covered my cameras with plastic bags and taped them shut, making it very difficult to change settings, switch lenses, or swap out batteries and memory cards without contaminating the gear. They told me that if any of my equipment was exposed, I'd be asked to leave it behind at the plant.

Photograph by Noriko Hayashi

David Guttenfelder on assignment inside Japan's nuclear zone.

Our two busloads of journalists and Tokyo Electric Power Company (Tepco) employees entered Daiichi through a checkpoint. We could see the ravaged exterior of the reactors. The buses stopped, and I first shot pictures from a distance. Then the buses followed a narrow road along the sea just 20 yards from the mangled outer wall of the four main units.

The place is devastated. The walls are sheared away. There was debris, standing pools of water, and overturned vehicles littered the ground. Dozens of hoses snaked through open doors or holes in the walls. We saw dozens of busy workers in other parts of the plant compound, but next to the reactors there was no sign of life. A Tepco worker on my bus called out through a plastic-covered bullhorn that the radiation meter he was holding showed 300 microsieverts inside the bus—safety experts say your health is at risk if you are exposed to more than that amount over a year.

It wasn't so easy to photograph. We were not allowed to get out of the bus; I had just a few minutes to shoot while the bus rolled past the plant. We were so close to the plant that my widest lens could only make a full frame of nothing but destroyed walls and debris, with little context to understand what we were looking at.

We also visited an emergency operation center near the reactors—a rare chance to see the faces of the workers who risk their lives every day. Many were in a giant room sitting at computers monitoring the plant systems. Other laborers were resting on the floor in a locker room. Everyone looked exhausted.