Water Batch Releases Set to Resume

San Onofre Nuclear Generating Station (SONGS) is set to resume water batch releases as progress on dismantling the plant continues.

The releases of slightly radioactive water from the site have occurred for more than 50 years and pose no harm to people or the environment because the amount of radioactivity is so small.

In 2020, the last year in which batch releases were performed, the 15 full releases (and two partial releases) measured a total body dose of 0.03 millirem, which is 0.996% of the annual allowable dose per the Nuclear Regulatory Commission. The numbers are reported here. We all receive about 620 mrem a year of radiation dose from natural and manmade sources, such as dental X-rays.

Release Point
The release point for the water batch releases is more than a mile off-shore and 50 feet below the surface.

See the samples

Batch Sample 2
A sample taken from the water that will be released on Monday.

The upcoming releases, two of about 100,000 gallons each, are sourced from run-off, HVAC condensation and various plant systems, including the reactor cavities. The spent fuel pool water releases will occur in the future.

The clean-up process the water undergoes is detailed here and involves ion exchangers and filters. Prior to release, the water is sampled and tested in a laboratory certified to perform the radioactivity analyses required to permit the release. This testing ensures the release is well below regulatory limits.

The release on Monday has a dose of 0.016 mrem which is 0.267% of the annual allowable limit. The lab on site tests and re-tests the samples prior to clearing them for release.

The actual release of water takes place more than a mile off-shore and 50 feet below the surface. The dilution rate is 87.5 to one. This remains the safest, most efficient and most effective method to remove this water from the site.

Batch Sample 1
A sample from the water that is set to be released Monday.

Find out more

As with all recent water batch releases, a 48-hour notification will be posted to the batch release page here. These are informational postings only and no public action is required.

The page features additional information including environmental reports and news and commentary on the process. Southern California Edison makes its environmental monitoring reports available online. The coast where SONGS is located is one of the most studied areas in California from an environmental perspective.