Edison: San Onofre [Nuke plant]could handle 7.0 quake

oc Register ^ | March 12, 2011 | MICHAEL MELLO

[BenLurkin]

When San Onofre was designed several decades ago, scientific studies showed that the largest tsunami likely to strike the San Onofre area would measure about 25 feet. The wall was built 30 feet high for extra protection, Alexander said.

As for earthquakes, the facility was built to survive a nearby earthquake with a magnitude 7.0, Alexander said.

During the plant's planning stages, "The best science suggested that the nearest earthquake fault, which is five miles from the plant, could produce an earthquake something less than a magnitude 7 in the plant vicinity," Alexander said.

He added that it wouldn't take a major event to trigger an emergency response.

"The plant is designed so that if ground motion sensors on the plant property detect even slight movement, an automatic mechanism will shut the two reactors down," Alexander said, by inserting control rods into the reactor cores to slow and stop the nuclear process. If need be, those rods can also be lowered manually. A total shutdown would take several hours.

The San Onofre plant provides enough electricity to power 1.4 million homes in Southern California.

Alexander said the company holds full-scale drills -- along with local, state and federal agencies -- five or six times a year to prepare for earthquakes and similar disasters.

[Vaduz]

The best science suggested that the nearest earthquake fault, which is five miles from the plant.

Until the next fault line was found last year.it runs half the length of the state.

[HereInTheHeartland]

A 7 number for worst case would be very low for disaster planning. I would question the accuracy of this.

[BigBobber]

This is what happens when reporters try to distill very complex subjects into a few sentences for laymen readers.

The ability of a fault to release energy is related to the length of the fault. The amount of energy transmitted to a site depends on a number of factors, including the type of fault movement, the distance from the site, and the foundation conditions.

When evaluating a structure for seismic loading ALL potential faults are looked at and complex calculations made to determine the most critical ground motions. A short close fault may be more critical than a bigger one far away.

This is a young science and each earthquake allows new evaluations worldwide. Upgrades then have the potential to make facilities safer over time.

[newzjunkey]

We’ve regulated ourselves into danger. We’re using old technology because building new modern energy generation plants is virtually impossible.

Well said. France, Japan and other nations continue to build new plants but we've not built one since 1974.

MSNBC already ran with an alarmist piece highlighting the 13 GE Mark I plants here in the U.S. and allegations of "design flaws." Completely irresponsible of them and far removed from the Japanese situation but they want eyeballs for ads and will do anything to get them even if it panders to mass hysteria.