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Up Front: Letters to and from the editor
Shelf Life: Books
Cliff Notes: Student life and sports
Class Notes: Alumni profiles
Looking Back: Thoughts on UCSD
Credits: Staff and Contributors
The Changing Face of Health Care
The Doctors
Community Medicine
Future Physicians
Campus Currents
Tracing a Tech Trajectory
Baja Hot Spot
River in the Sky
Japanese Radiation
Reengineering Engineers
The NatGeo Connection
Kinect with Archaeology
White House Honor
New 24-Hour Study Space
Are Black Holes Galactic Killers?

Campus Currents May 2007: Volume 4, Number 2

Japanese Radiation

Was radiation from the Fukushima Daiichi nuclear power plant in Japan measureable on the West Coast? When an 8.9 magnitude earthquake followed by a tsunami demolished cooling systems, and their backups, at the plant last March, desperate managers turned to seawater to douse the overheating fuel.

Nearly all of the seawater vaporized as it hit the hot reactors and the chloride ions in the water were transformed into a radioactive form of sulfur. To avert explosions, this was vented into the atmosphere where winds swept it eastward across the Pacific Ocean all the way to La Jolla.

Atmospheric chemists led by Mark Thiemens, dean of the division of physical sciences, captured that airborne signal. Although levels were very low, and were not a threat to human health, they were enough to estimate the extent of damage to the reactor cores.

From their understanding of physical chemistry and accounting for losses along the way, the team calculated that concentrations of radioactive sulfur a kilometer or so above the ocean near Fukushima must have been about 365 times higher than natural levels to account for the levels they observed in California.

—Susan Brown