SAN ONOFRE, Calif.—Radiation experts and emergency workers at the San Onofre nuclear plant drilled today in response to a simulated radiation leak as part of scheduled exercise that took on new significance in light of the disaster in Japan.

The drill, which included an emergency shut-down and securing fuel rods, was done in secret, but experts on nuclear plants and other officials gathered at an information center, where they practiced getting out essential information as if a radiological disaster had occurred. Public health employees from Los Angeles, Orange, Riverside and San Diego counties also are participating.

Drills are done at the plant a few times a year, but today's—conducted every other year—was the most extensive monitored by the Federal Emergency Management Agency, said Gil Alexander of Southern California Edison, which operates the plant.

The main difference this year, according Tina Walker of the California Emergency Management Agency, was interest in the drill, because of the disaster in Japan. She said that was a positive change, because Southern Californians should know what to do in a nuclear emergency.

"One of the key steps is to know the resources in your local jurisdiction,'' Walker said. "The best way someone can protect themselves and their family is to know your local resources. Speak to your local officials on emergency planning and once you get that information under your belt you'll be prepared for anything.''

Alexander said SCE officials hoped that increased new coverage of the drills would help calm fears, as the Japanese try to contain radiation flowing from the earthquake- and tsunami-crippled Fukushima Daiichi plant. "We're hopeful the news stories this week will show our extensive planning efforts,'' Alexander said. "We hope the reports on all of this will be reassuring to the public.''

The drill at San Onofre simulated a radioactive leak that goes beyond the plant's boundaries, Alexander said.

At 4 p.m. Friday, FEMA officials will hold a meeting at Capistrano Unified School District offices to give the public a "snapshot'' of how the drills went, John Hamill of FEMA said.

In about three months, FEMA will issue a "report card'' on the drill, Hamill said.

Also on Friday, Edison will ask for $64 million from the state Public Utilities Commission to do more research on how earthquakes or seismic waves could damage the San Onofre plant.

"We have been planning the seismic and tsunami studies for several months,'' said Pete Dietrich, Edison's chief nuclear officer. "Following the recent tragic natural disasters in Japan, we reevaluated and enlarged the scope in order to further increase the scientific information we could obtain.''

The California Emergency Management Agency is coordinating the drill, which started today and concludes Thursday.

Workers will test emergency shut-down procedures and practice securing radioactive fuel rods.

San Onofre's two reactors generate about 2.1 billion watts of electricity at full capacity. Both units have undergone major overhauls in recent years.