SLOMFP/FOE challenge Diablo Canyon embrittlement


On September 14, 2023, Diane Curran and Hallie Templeton, legal counsel for San Luis Obispo Mothers for Peace (SLOMFP) and Friends of the Earth (FoE), respectively, submitted an emergency shutdown petition with the U.S. Nuclear Regulatory Commission (NRC) Commissioners regarding Diablo Canyon Unit 1 in California (pictured alongside Unit 2, overlooking the Pacific Ocean, above).

The groups have demanded the NRC Commissioners order the emergency shutdown of the reactor, at least until Pacific Gas & Electric (PG&E) withdraws and tests a capsule, and carries out an Ultrasonic Test (UT) inspection, to prove that the reactor pressure vessel is not dangerously neutron-embrittled. Shockingly, the last such inspections were carried out in 2003, and 2005, respectively.

Dr. Digby Macdonald serves as the environmental coalition’s expert witness.

See the groups’ press release, with a link to both the emergency shutdown petition, as well as Dr. Digby’s declaration and C.V.

Embrittled reactor pressure vessels (RPVs) are at risk of pressurized thermal shock (PTS). Like a hot glass under cold water, the RPV could fracture, through-wall, like a hot glass under cold water — only at a ton or more of pressure per square inch. A reactor core meltdown would follow. If containment also failed, catastrophic amounts of hazardous radioactivity would escape into the environment, harming people downwind, downstream, up the food chain, and down the generations.

In a four-part series, “Aging Nukes,” published not long after the Fukushima nuclear catastrophe in Japan, AP investigative reporter Jeff Donn cited embrittlement/PTS as a top example of NRC regulatory retreat, unfolding over decades.

Dr. Arjun Makhijani of Institute for Energy and Environmental Research, in the context of the proposed Yucca Mountain high-level radioactive waste dump on Western Shoshone land in Nevada, referred to such executive branch moving of the goal posts as “double-standard standards” — when the proposal can’t meet the established safety, health, and environmental protection standards, simply weaken, or entirely remove, the troublesome standards.

Nearly a decade ago, Beyond Nuclear, along with Don’t Waste Michigan and Michigan Safe Energy Future, helped lead similar interventions at the Palisades atomic reactor, on the Lake Michigan shore in Covert Township, Michigan. Terry Lodge of Toledo, Ohio, served as legal counsel, and Arnie Gundersen, chief engineer at Fairewinds, served as expert witness. Fairewinds produced a humorous educational video (“Nuclear Crack Down?“), as well as a precautionary essay (“Downstream“), about embrittlement risks at Palisades. Beyond Nuclear published an annotated bibliography of relevant documents, dating from the 1940s to 2014.

In March-April, 2013, Beyond Nuclear questioning forced the NRC to admit that Palisades was essentially tied for worst-embrittled reactor pressure vessel (RPV) in the U.S., with Point Beach Unit 2, on the opposite shore of Lake Michigan in Wisconsin. Indian Point Unit 3 on the Hudson in New York — permanently shut, thankfully, on April 30, 2021 — was next worst, followed by Diablo Canyon 1 and Beaver Valley Unit 1 in Pennsylvania. (See page 5 of 15 in this NRC document, point #4.)

Coalition for a Nuclear-Free Great Lakes first documented serious embrittlement concerns at Palisades in 1993. Nuclear Information and Resource Service joined with Don’t Waste Michigan in the resisting Palisades’ 20-year license extension in 2005, primarily citing the embrittlement dangers. Palisades’ original owner, Consumers Energy, even admitted to the Michigan Public Service Commission in spring 2006 that a main reason for its decision to sell the plant to Entergy was “Reactor vessel embrittlement concerns.”

Alas, the challenges at Palisades ultimately failed to accomplish permanent shutdown of the very high-risk reactor. Entergy did shut it down, supposedly permanently, on May 20, 2022. But the new owner, Holtec, pulled a bait and switch. Instead of proceeding to dismantle and decommission Palisades — its stated reason for taking over ownership — on September 9, 2022, it announced it would instead attempt to restart the reactor. Any such “zombie reactor restart” at Palisades would mean sailing ever deeper into uncharted risk territory.

Diablo Canyon 1 & 2 were supposed to be shut down in 2024 and 2025. Instead, PG&E, in cahoots with Governor Newsom, the California state legislature, and the U.S. Department of Energy, reversed the shut down agreement, planning many additional years of continued operations.

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