By John Stang
Arguing that a worst-case scenario could result in geysers of radioactive water erupting on the California coast, an advocacy organization filed a new petition Tuesday to the Nuclear Regulatory Commission to stop the decommissioning of the retired San Onofre Nuclear Generating Station. (SONGS).
SONGS majority owner Southern California Edison countered that the scenario laid out by Public Watchdogs has been studied and found impossible.
This is the latest effort by California advocacy groups to halt the ongoing offload of spent fuel into dry storage on the San Diego County property, along with decommissioning of the plant’s last two reactors.
Last year, Public Watchdogs and Oceansiders Against San Onofre Corruption submitted separate 2.206 petitions on SONGS. Public Watchdogs sought an immediate halt to decommissioning of the reactors, saying the NRC had breached federal law and its own rules by not conducting further environmental review before allowing the work to proceed. Oceansiders’ petition asks the federal regulator to revoke a 2015 California Coastal Commission permit allowing for expansion of SONGS’ dry storage site.
A 2.206 petition is a bureaucratic avenue for outside groups to request enforcement action by the NRC.
In December 2019, the NRC told both groups by email that previous environmental impact studies on SONGS’ decommissioning cover all the pertinent issues and that new assessments would not cover any additional ground. Both groups in January offered oral arguments to an agency petition review board to try to persuade the NRC to reverse its earlier position. The board’s decisions on those final arguments have not been announced yet.
Also in December, Judge Janis Sammartino of U.S. District Court for Southern California dismissed a Public Watchdogs lawsuit against the NRC and Edison that that covered roughly the same issues at its 2.206 petitions, seeking a halt to the spent fuel transfer.
By this summer, Edison and contractor Holtec international expect finish moving 3.5 million pounds of fuel assemblies from pools to a dry storage site that is 18 feet above sea level and 108 feet from the ocean. That work is about two-thirds completed, with 48 of 73 canisters transferred to storage as of this week.
Mishaps in the fuel offload have increased local concerns about keeping highly radioactive material in a seismically active, densely populated region along the Pacific coast. Most notable was an August 2018 incident in which one used-fuel canister was left at risk of dropping nearly 20 feet into its storage slot. That event led to a nearly yearlong halt to the project while SCE and Holtec made improvements to their processes, and also drew a $116,000 NRC fine of the utility for violation of nuclear safety rules.
In a statement on its latest 2.206 petition this week, Public Watchdogs said flooding from the Pacific Ocean could cause SONGS’ spent fuel dry storage site to “erupt with deadly radioactive steam geysers.”
The specific mechanism for that to happen would involve water flowing between the walls of the vertical apertures used for storage and the canisters that contain the spent fuel assemblies, Public Watchdogs said. If the water seeps into the canisters themselves, a criticality — an uncontrolled burst of radioactivity — could occur, the petition says. The exteriors of the canisters are 452 degrees Fahrenheit, so the introduction of cold ocean water would convert into steam, which could be radioactive and erupt like a geyser, the press release contends.
In this case as well, Public Watchdogs wants decommissioning activities stopped, including movement of the spent fuel to dry storage. Among other requested actions in the petition are preparation of countermeasures against landslides and flooding and revoking exemptions on emergency preparedness requirements from 2015.
Edison countered that it has studied the scenario covered in Public Watchdogs’ petition, and that the organization’s worst-case theories are flawed.
“The Public Watchdogs’ documents contain multiple errors. For instance, the outside shell of the warmest- spent fuel storage canister on site is approximately 225 degrees Fahrenheit, not an average of 452 degrees Fahrenheit,” the utility said in a prepared statement. “This one fact alone undercuts the entire ‘geyser’ narrative. Water is a better conductor of heat than air and actually would serve to more efficiently cool the canisters.”
A mix of cold ocean water and the hot canisters would cause the water to boil, but not erupt in a geyser, Edison’s statement said.
The petition also calls for decommissioning to stop at SONGS because tsunamis or rising sea levels from climate change could flood the dry storage site. — and this scenario’s effects have not been studied.
Edison said it has also studied flooding and tsunamis scenarios and determined that they would not result in the dry storage site being totally submerged. The Holtec-manufactured canisters are also designed to remain intact under 125 feet of water, the statement said.
If the NRC believe the petition should be addressed, it will form a review board specifically for this matter. There is no timetable, but the NRC must update public Watchdogs every 60 days on its petition’s status.
Southern California Edison retired SONGS Units 2 and 3 in 2013 after they were equipped with faulty steam generators. Decommissioning of the two reactors is underway, a $4.4 billion job managed by SONGS Decommissioning Solutions. Disassembly and removal operations for buildings, reactor domes, and other structures is scheduled to begin this month.
SONGS Unit 1 closed in 1992 and has been largely decommissioned.
