Retiree Bret Gross of San Clemente loves Southern California weather and the seashore. Yet he's ready for a quick getaway, leaving his car's tank at least half full of gasoline.

Is he worried about earthquakes? Yes. Wildfires? Sure. Floods? Yep.

And then there are those two San Onofre nuclear power reactors five miles down the road. Gross worries that the area cannot be quickly evacuated in a severe nuclear accident.

"Forget the amount of training and plans," he said. "It'll be ugly."

Residents near 12 of 65 U.S. commercial nuclear power sites were interviewed following an Associated Press investigative series that reported population increases of up to 4? times since 1980 within 10 miles of plant locations.

Those interviewed voiced a mixture of anxiety, confidence and resignation about the safety of reactors. Many doubted they can safely and quickly evacuate in a major accident. Despite the existence of formal evacuation plans, many said they didn't even know where to go. They predicted confusion and panic on crowded roadways.

Some vowed to ignore instructions to take initial shelter at home - a strategy increasingly favored by disaster planners in the face of population expansions. Some residents said they have devised their own emergency plans, intending to ignore official directives.

By law, evacuations must be prepared for areas within about 10 miles of every nuclear plant, but many plans haven't kept up with changing populations, according to the AP investigation.

Also, federal regulators don't set standards for how quickly people must be capable of evacuating. Meanwhile, aging reactors have been operating at higher power, risking larger radioactive releases.

Despite population growth, many residents insisted they are relatively comfortable living near nuclear plants. Many work at a plant or live with someone who does.

South of Miami, the population around the Turkey Point plant quadrupled to 155,118 over the past 30 years. Two miles away in Homestead, retired industrial engineer Clara Waterman Powell said nuclear power is "the way of the future." She said she trusts plant workers, yet she can't imagine an orderly evacuation. "If everybody got in the car and started driving, where would we go?" she asked.

In Fort Calhoun, Neb., about five miles from the nuclear plant with the same name, 86-year-old Feris Stevenson said he doesn't worry much about its safety. To him, it's "just another power plant."

Regarding a possible accident, he added, "Why worry about something you can't do anything about?" He thinks it would be hard to evacuate, especially with the Missouri River flooding areas around the plant. "We've got one major road getting out of here," he said, referring to U.S. Highway 75.

Larry Jones and his wife, Jean, have lived in Blair about three miles from the Fort Calhoun plant for 30 years. "It's always in the back of your mind," she said.

The couple said they are unsettled by the memory of hearing long ago that the plant, which opened in 1973, was not designed to last until now. The AP investigation found that federal regulators have been relaxing safety standards to keep aging reactors within the rules and therefore extend their lives.

Serious weaknesses also were found in evacuation plans, including the failure to test different scenarios involving the weather or the time of day. And evacuation zones have remained frozen at 10 miles since they were established in 1978, before the accidents at Three Mile Island, Chernobyl and Fukushima Dai-ichi in Japan.

Some watchdogs say evacuation standards also are kept lax to keep plants running, as nearby populations swell.

At the two-unit Calvert Cliffs site, population within 10 miles has ballooned by 224 percent since 1980, to 48,843.

Darlene Cocco-Adams, an attorney who lives in Lusby, Md., nine miles from the site, predicted havoc in a nuclear emergency. She said there's just one main road leading out of town, and it sometimes backs up "like New York traffic."

"You couldn't get out of here fast enough," she said.

Many residents living near plants said they regularly receive emergency instructions, usually from the plant operator. Some post them on refrigerators or carefully file them. Others simply toss the document, or stuff it into a drawer and forget about it.

"I just throw it away because we're goners anyway" in a severe accident, said Debra Dominski, 52, who has lived in London, Ark., two miles from the twin reactors of Arkansas One in Russellville, for the past 20 years.

Steven Kerekes, a spokesman for the industry's Nuclear Energy Institute, said "evacuations can work well," with traffic rerouted in a single direction during an emergency.

He said a June survey conducted for NEI found that 81 percent of 1,152 adults living within 10 miles of a nuclear facility said they know what to do in an emergency, with 45 percent "very well informed."

Glenn Cannon, director of emergency management for Pennsylvania, said evacuation is possible. "How quick it is depends on the population you're trying to move and what those road resources are," he said. The state is home to nine operating reactors on five sites, including one unit at the Three Mile Island facility, where the nation's worst nuclear accident occurred in 1979.

Gwen Keenan, bureau chief for preparedness at Florida's emergency agency, acknowledged that evacuations could be complicated by people who flee even though they are told to stay put.

"The roads have the capacity. We have the capacity to get out the word," she said of Florida. "I think the biggest wild card is the behavioral aspect: Will people listen?"

The U.S. nuclear industry's most explosive growth has occurred on the Florida's east coast, around the two-reactor Saint Lucie complex near Fort Pierce, where the 10-mile population of 43,332 in 1980 grew 366 percent to 202,010 in 2010.

Retired clock maker Phil Hollis, of Jensen Beach, Fla., lives six miles from St. Lucie and says he feels little worry.

He thinks he received - but didn't read - emergency instructions mailed by the plant operator.

He's uncertain what route to take in an emergency. "I'd just head west" away from the ocean, he guessed.

Many residents were at a loss to explain why they pay so little attention to planning for a nuclear emergency, including some who should perhaps know better.

Barb Tummel, 48, of Monticello, Minn., drives a school bus and lives within two miles of the Monticello plant, where the 10-mile population rose 314 percent to 58,538 over the past three decades.

Her parents both retired from the plant, and she trusts in its safety. As a driver, she said she knows the city plan for evacuating children from schools in a nuclear accident.

But she wasn't sure how she'd handle an accident when school isn't in session. "I think in the calendar they give out every year, I'm sure there's a page on evacuations. I don't necessarily read all those pages."

And she admitted she has no family plan: "I don't. I should, though."

At Crystal River on Florida's west coast, the population has more than doubled since 1980. Nancy Little Lewis, 53, a real estate broker and advocate of nuclear power, has lived 12 miles away for 17 years and believes it is quite safe.

However, she says there should be some standard for how long evacuation can take and can't imagine following official instructions to stay at home in a major nuclear accident. "I wouldn't do that. We're not talking about a hurricane. We're talking about something much worse," she said.

Others asked, what would be the point of a standard for evacuation times?

"It wouldn't work anyway," said Judith Freed, a psychotherapist in Guilford, Vt., who has lived seven miles from the Vermont Yankee plant for 40 years. She said country roads in that area could not handle an evacuation.

Many residents said they had come up with their own evacuation strategies. Lynn Baldwin, 42, of Soddy-Daisy, Tenn., and her husband live within three miles of the two-unit Sequoyah plant.

She said their family plan is based on typical wind patterns. If it's blowing one way, they meet in Dayton; the other way, at her husband's job in town. "He said, 'Go this way if it's blowing that way'" she explained, laughing.