REGION — On Dec. 19, 250 gallons of what was supposed to be 19,200 gallons of operational wastewater from the San Onofre Nuclear Generating Station was dumped into the ocean just over a mile offshore from the plant.
Southern California Edison, the plant’s owner, originally announced on Dec. 17 that it would release 19,200 of operational wastewater just over a mile off the coast 50 feet below the surface on Dec. 19. According to spokesman John Dobken, only 250 gallons were released before the process was stopped due to an equipment issue.
Wastewater release has a routine occurrence at SONGS, according to Southern California Edison (SCE), the plant’s owner. Edison submits annual release reports to the Nuclear Regulatory Commission (NRC).
“SCE has been safely cleaning and discharging these liquids for more than 50 years with no measurable impact on the environment,” states Edison’s announcement of the release.
When the plant was still running, these kinds of dumps were done frequently — even daily at times. After the plant shutdown in 2012, wastewater batch releases “have dropped dramatically.”
The wastewater that was discharged included non-radiological and radiological materials. According to Edison, the non-radiological releases like sewage met the criteria its National Discharge Pollutant Elimination System permit implemented by the State Water Resources Control Board.
The NRC governs the radiological releases.
Batch releases have a set volume of water from a specific tank unlike continuous industrial wastewater releases that come from other plants. The water is placed in a tank, circulated through ion exchangers and filters and then sampled prior to release to ensure it meets regulatory requirements.
“Once the water discharged mixes in the ocean, the dose further drops as it is further diluted,” Dobken told The Coast News via email.
According to Edison, the release’s total radiological dose is 0.00183 mrem, which is 0.0321% of the annual whole-body dose limit.
Mrem is short for millirem, which is one thousandth of a rem (0.001 rem). Rem stands for roentgen equivalent man, which is a unit used to measure health effects of low levels of ionizing radiation on humans.
“Surprisingly, this is well within their legal allowance set by the NRC, which has a maximum annual dose limit from liquid effluent of 3 mrem per unit,” states the Surfrider Foundation in its notice to members.
The Surfrider Foundation is an organization headquartered in San Clemente with reaches across the country that aims to protect the ocean, waves and beaches.
Surfrider is against permanent or long-term storage of spent nuclear fuel at SONGS because of how close the facility is to the water. SONGS has two independent spent fuel storage installations (ISFSI) where spent fuel is kept in dry storage.
Though batch releases of wastewater have been a decades-long routine for the plant, this is the first time the public is being notified in advance of a release. According to Surfrider, this is consistent with the foundation’s effort to increase Edison’s transparency and public knowledge about what is happening at the plant.
Edison’s notice of the batch release was posted 48 hours prior to the actual release on its SONGS Community website.
“As part of the approval of our lease for the off-shore facilities with the California State Lands Commission, we committed to notifying the public 48 hours in advance of future releases,” Dobken said via email. “Though this commitment was to start with decommissioning activities, we decided to begin the notifications early, before decommissioning activities started, in the spirit of providing the local community with more information.”
These kinds of releases will continue as the plant undergoes dismantlement throughout the next decade. The initial set of releases will be approximately 20,000 to 25,000 gallons in volume. The process usually takes between four to six hours; the Dec. 19 release took four hours to complete.
Releases are done through the Unit 2 conduit that extends more than 8,000 feet, about 1.5 miles, into the ocean. The discharge of the wastewater occurs in the diffuser section, which begins around 6,000 feet out, or 1.1 miles from shore.
Dobken said Edison doesn’t have a firm date on when the next release will occur, but it will likely happen after the first of the year. Edison will once again give a 48-hour notice prior to the release.