Frequently Asked Questions – Liquid Batch Releases

What are liquid batch releases?
Liquid batch releases comprise a set volume of water from a specific tank, as opposed to continuous wastewater releases. The water is placed in the tank after being cleaned up via ion exchangers and filters to remove radionuclides and impurities, and then sampled prior to release to ensure it is safe and it meets stringent regulatory requirements.

Are these releases regulated?
Yes, the Nuclear Regulatory Commission sets release limits to ensure safety for the environment and the public. The NRC annual allowance for SONGS is 6 millirem (mrem) of dose from liquid effluents. San Onofre discharges are only a very small fraction of the allowable limit. Compare this to natural sources of radiation (such as the sun or the food we eat) that contribute about 300 mrem per year to the average person. Man-made sources, such as x-rays, contribute another 300 mrem a year.

How are you allowed to do this?
SCE, just like other industries, has federal permits that allow for treated discharges. In this case, the discharges comply with NRC requirements and our National Pollutant Discharge Elimination System permit from the EPA (as regulated by the San Diego Regional Water Quality Board) and meet Clean Water Act standards.

Batch Release Steps v2

How do you verify what you’re releasing is safe?
We ensure the discharges are safe by making sure that they are well below regulatory limits, and further – we conduct environmental monitoring so that we’re certain that there is minimal impact to people or the environment. A required environmental monitoring program includes periodic samples of ocean water, marine life (e.g. fish and crustaceans), kelp, ocean bottom and shoreline sand, all of which are analyzed for radioactivity. Each commercial nuclear power plant in the U.S. is required to submit two annual reports which detail (1) the radioactive effluent discharged from the site, and (2) the effects (if any) on the environment. These past reports are available on the NRC website and recent reports are on the SONGS Community website.

Fast Fact: We all receive about 620 mrem of radiation exposure a year from natural and (non-nuclear plant) man-made sources, according to the NRC. All water on Earth contains small amounts of dissolved uranium and thorium. The average person receives an average internal dose of about 30 millirem from naturally occurring radioactive materials including uranium, thorium, and potassium in the body.

If I’m swimming or surfing at San Onofre, is there any harm to me?
No and here's why. First, the dose is already small to begin with, diluted in thousands of gallons of water. Once released to the ocean, it mixes with vast quantities of ocean water. This serves to further dilute the discharge and reduce the dose below measurable levels. Second, radiation exposure to humans is based on pathways, the routes by which radioactivity might be transported. The primary pathway for liquid releases would be eating seafood (fish, crustaceans) that might accumulate radioactive material. There is no drinking water pathway for SONGS since there is no potable water near the site.

Here’s what you should know: environmental monitoring confirms that the releases have no measurable impact on the environment, including sampling of fish, crustaceans, ocean water, shoreline sediment, ocean bottom sand, and kelp.


SONGS has done these types of releases for 50 years, why are you telling us now?
There’s no discernible difference between past releases and the ones we will be doing during decommissioning. A local organization, Surfrider, requested SCE begin public notifications of the releases and SCE included the language in the California State Lands Commission lease for our off-shore facilities. Posting the information supports our long-standing commitment to sharing decommissioning information with the public.

Will the releases happen exactly 48 hours after the notification to the public?
Not necessarily. The release permit allows batch releasing up to a week after initial sample time. This means that the release could occur as many as 5-7 days after the 48 hour notification posting time.