There are no views of the Calvert Cliffs Nuclear Power Plant from any of the major roads that run through Lusby. Its two reactors sit in a wooded area along the Chesapeake Bay. The entrance is marked by a modest sign. But for those who live within its 10-mile evacuation zone, the plant makes its presence known in other ways.

There are siren towers and free supplies of potassium iodide pills at the health department. There is the feeling of unease on the part of drivers sitting in traffic on the two-lane Thomas Johnson Bridge — the main evacuation route for towns south of the plant. And then there are crises at other nuclear power plants such as the one at the Fukushima Daiichi facility in Japan triggered by last Friday’s massive earthquake and tsunami.

Many residents take comfort in knowing that Solomons Island doesn’t sit on a faultline the size of the San Andreas, and the Chesapeake Bay has more Atlantic sturgeon than it does tsunamis.

“The circumstances are completely different here. What’s more likely are hurricanes and tornadoes,” said Susan Shaw (R-Huntingtown), president of the Calvert Board of County Commissioners.

Shaw and others also note that there is a difference in the design of the reactors at the two plants. The Fukushima Daiichi plant has boiling water reactors, in which the water that circulates around the core turns into steam that is then used to turn turbines and generate electricity.

The Calvert Cliffs plant, by contrast, has pressurized water reactors, in which the water that circulates around the reactor’s core is kept under pressure so that it stays in liquid form. The liquid, which is radioactive, is then pumped through a series of tiny tubes. More water circulates around the tiny tubes and turns into steam used to generate electricity.

The difference in design, however, doesn’t necessarily make one safer than the other, experts said. The reactor at Three Mile Island near Middletown, Pa., which resulted in a partial-core meltdown, was a pressurized water reactor.

“They have different vulnerabilities to different events,” said Mohammad Modarres, a nuclear engineering professor at the University of Maryland.

Mark Sullivan, a spokesman for Constellation Energy Nuclear Group, which owns and operates the Calvert Cliffs facility as part of a joint venture with Europe-based EDF Group, said the plant has a “sterling” safety record, and is designed to withstand “natural events as big as would reasonably be expected to occur, with some extra safety margin built in.”

The Calvert Cliffs plant is designed to shut down “if certain seismic thresholds are met,” Sullivan said, though he could not name a specific earthquake magnitude. The Nuclear Regulatory Commission also requires plants be built to withstand natural calamities such as tsunamis.

Sullivan said the plant plans to deal with “even greater events if warranted.” Those plans are reviewed regularly by federal, state, and local government agencies. The plant, which is located about 50 miles south of Washington, also has training exercises and drills to ensure that staff can effectively carry them out.

In 2002, Calvert Cliffs came close to being tested by a natural disaster, when a tornado with winds that topped 200 miles per hour passed near the plant.

Plans to build a third reactor at Calvert Cliffs stalled recently when a major investor withdrew its backing for the project, leaving EDF Group to hunt for a new partner. County leaders had strongly supported the construction of a third reactor because the project is likely to generate hundreds of jobs for local residents. The plant employs close to 1,000 people and pays for 12 percent of the county’s tax bill, Shaw said, and “keeps our property taxes at a reasonable level.”

Few local residents have publicly expressed concerns about the plant’s safety or about expanding it. During hearings several years ago about adding another reactor, most of the opponents who showed up did not live near the plant, or even in the county.

One reason, said several residents, is that speaking out against the plant is unpopular.

Norma Powers, who lives in Dowell, about eight miles from the plant, has been the most vocal resident critic.

Powers moved to the area in the 1980s for a job with the U.S. Navy, years before she learned she would be neighbor to a nuclear power plant. Now 72, she lives on a street with a siren tower. She gets an earful when the plant tests them quarterly.

She has envisioned catastrophic scenarios, such as an explosion at the liquid natural gas plant that is practically next door to the nuclear power plant. “Mother Nature has proven she can exceed reasonable expectations,” she said.

The possibility of an accident “always crosses our mind. It’s a constant worry,” said Megan Dinopoulos, 45, of Lusby. She said she thinks about it whenever she gets stuck in traffic on the Thomas Johnson Bridge. Crossing the 1 1 / 2-mile span can take as long as 45 minutes.

Powers said she and her husband, Bill Lewis, have yet to pick up free potassium iodide pills at the health department because theydon’t plan to stick around in the event of a meltdown. “I’m going to get the [heck] out of here,” she said.

And therein lies one of her main issues: the dearth of evacuation routes. For those south of the plant, Route 4 is not possible since it goes right past the plant.

Her other option is to take to the water. “If we had a fast boat,” Powers said, “but we have a sailboat, so that wouldn’t do.