San Onofre has the worst safety record of all nuclear power plants in the United States, according to the U.S. Nuclear Regulatory Commission. Numerous safety hazards have been confirmed over the years, including, most recently, failure to comply with fire-safety regulations. Fires pose one of the greatest risks for causing a core meltdown, which would release tons of radiation and threaten the lives and environment of the communities surrounding the reactors. San Onofre has been in violation of these fire regulations for more than 30 years.
Radiation and health risks
All nuclear power plants release radioactivity in either liquid or gaseous form into the environment on a daily basis. The two reactors at San Onofre release more than 30 radionuclides every day into the atmosphere of Southern California, including highly dangerous Strontium-90 and Caesium-137. Liquid releases into the Pacific Ocean comprise more than 20 radionuclides, including Iodine-131 and Caesium-137.
The March 11, 2011, earthquake and tsunami that destroyed the Fukushima-daiichi nuclear power plant in Japan has raised worldwide concern about the seismic risks to nuclear reactors. Decades before the Fukushima nuclear catastrophe, however, there were widespread concerns over the earthquake risk at the San Onofre nuclear reactor site. The reactors are located in an area of active seismic activity on the Pacific coast of Southern California. The two reactors at the site were originally designed to withstand a magnitude-6.5 earthquake. After citizen groups in the mid-1970's challenged these standards, Southern California Edison “redesigned” the plant to take account of a magnitude-7.0 earthquake.
The nuclear waste crisis
San Onofre, like all other nuclear power reactors, produces radioactive nuclear waste. The most hazardous waste at the San Onofre site is the contaminated radiation fuel that is removed from the reactors every 22 months or so during refuelling, also called spent fuel. Spent fuel is highly dangerous: Human exposure to an unshielded container would prove fatal. Other dangerous fission products are contained within the spent fuel – particularly caesium and plutonium, among many others.