I will add to this post as more information becomes available.
SAN ONOFRE (KTLA) -- A level 3 emergency is being reported at the San Onofre nuclear plant Tuesday.
Alarms and sirens were activated at the plant earlier this afternoon.
Officials say the Emergency Operation Center has been activated at the plant.
From the information guide for area residents:
What is an emergency?
An emergency can be a problem, or a potential problem, at SONGS. Federal guidelines classify emergency conditions into four levels depending on the situation. They are:
1. Unusual Event
Events are in process or have occurred which indicate potential degradation in the level of safety of the plant. No release of radioactive material requiring offsite response or monitoring is expected unless further degradation occurs.
Events are in process or have occurred which involve an actual or potential substandard degradation in the level of safety of the plant. Any releases of radioactive material from the plant are expected to be limited to a small fraction of Environmental Protection Agency (EPA) guidelines.
3. Site Area Emergency
Events are in process or have occurred that result in actual or likely major failures of plant functions needed for protection of the public. Any releases of radioactive material are not expected to exceed EPA guidelines, except near the site boundary.
4. General Emergency
Events involve actual or imminent substantial core damage or melting of reactor fuel with the potential for loss of containment integrity. Radioactive releases during a General Emergency can reasonably be expected to exceed the EPA guidelines for more than the immediate site area.
Orange County Sheriff’s officials say that there was an incident at the plant at approximately 3:10 p.m. Tuesday. The plant and its employees are under a Level 3 Alert, which means there is a serious incident according to the International Nuclear Events Scale.
The classification could me anything from a near accident to a lost radioactive device. There is also a very low probability of public exposure.
No radiation is currently escaping from the power plant, Lt. Roland Chacon said. The Orange County Emergency Operations Center has been activated.
4:12 PM PT: For those not familiar with the area San Onofre is between the cities of San Diego and Los Angeles on the coast.
4:17 PM PT: The lowest marked city on the coast is San Onofre.
I'm working to find a more general area map.
4:31 PM PT: The situation appears to be an ammonia leak. Ammonia was used as a coolant material before freon was developed and is still used in some industrial applications.
Ammonia leaks themselves can cause fatalities and other medical injuries. There have been no reports of injuries.
This is a developing incident.
Apparently ammonia is used as a solvent in this application. There is also confusing reports as the alert level called in this incident.
Ammonia is used to clean away resin as part of the purification system for the plant's steam water system. The deck is located between the nuclear area and the ocean at the seaside nuclear plant providing power to both SoCalEdison and San Diego Gas and Electric customers.5:46 PM PT:
An emergency alert was declared at the lowest level on a four-tiered scale, Alexander said.
"There is no imminent danger or threat to public health or safety," he said. "We have begun a precautionary evacuation of some plant workers whose jobs are located close to where the leak was found."
SAN ONOFRE (KTLA) -- Edison officials say an ammonia leak has been contained after triggering a level 2 emergency at the San Onofre nuclear plant Tuesday.
6:50 PM PT: From NBC San Diego on Twitter:
Officials have lifted the alert at the San Onofre Nuclear Power Station; they report the leak of ammonia was 30 gallons total.