By Al Gedicks*
On July 31, 2021 the operators of the Point Beach Nuclear Plant on the shore of Lake Michigan had to shut down the 52-year-old reactor after a cooling pump failed and waste heat was vented into the atmosphere.
According to Physicians for Social Responsibility and Nukewatch, two anti-nuclear groups, the shutdown “was caused by a failure to adequately monitor and maintain the aging and outmoded components in the Point Beach reactor” (“Questions about nuclear safety,” La Crosse Tribune, August 14, 2022).
ups have told the Nuclear Regulatory Commission (NRC) that the plant is operating beyond the 40- year lifespan of its 1960s design and questioned the agency’s oversight of the plant’s safety.
One of the most serious safety questions for aging nuclear reactors is the problem of neutron embrittlement of the nuclear reactor. Scientists have long been aware that neutron radiation from inside the nuclear core would gradually destroy the thick metal reactor that surrounds the core.
According to nuclear expert Arnold Gundersen: “If embrittlement becomes extensive, the dense metallic reactor can shatter like glass…creating what the NRC calls a Class 9 Accident, which is the worst nuclear catastrophe acknowledged by the NRC…The NRC has identified that NextEra’s Point Beach Reactors are the most embrittled operating reactors in the United States.” NextEra Energy is the owner of the Point Beach Nuclear Plant in Two Rivers.
Neutron embrittlement happens to all reactors, but the issue is especially crucial in reactors built before 1972, such as Point Beach. Those vessels were built using copper – which is no longer used in reactor construction because it is more prone to embrittlement – in the walls and welds.
The NRC estimated that both the Point Beach 2 reactor, located on Wisconsin’s Lake Michigan shoreline, and the Palisades nuclear power plant, also located on the Lake Michigan shoreline in Covert, Michigan, were expected to reach the traditional embrittlement screening limits in 2017. Some scientists have called embrittlement the single most important factor in determining the life span of a reactor.
Unlike the Palisades reactor that has announced permanent closure by May 31, 2022, Point Beach has sought permission to operate 20 more years, despite increasing age-related degradation risks. The current licenses for the two reactors are set to expire in 2030 and 2033.
With thermal shock from rapid cooling or from overheating, the steel vessel could crack, releasing coolant from around the fuel rods, leading to a core meltdown, as it did at the Fukushima Daiichi site in Japan on March 11, 2011. Pressurized thermal shock is a problem most severe in the older generation of reactors such as Point Beach.
In 1982, Demetrios Basdekas an NRC Reactor Safety Engineer, expressed his concern about the age-degradation risks of reactor embrittlement in a letter published in the New York Times: “There is a high, increasing likelihood that someday soon during a seemingly minor malfunction at any of a dozen or more nuclear plants around the United States, the steel vessel that houses the radioactive core is going to crack like a piece of glass. The result will be a core meltdown, the most serious kind of accident, which will injure many people, and probably destroy the nuclear industry with it.”
The casualty and property damage figures from the NRC’s “CRAC-2 Report on Accident Consequences for Point Beach, Units 1 & 2, Two Rivers, Wisconsin,” show that a reactor meltdown would have catastrophic negative impacts on health and the economy of nearby neighborhoods and the people who live and work in those communities.
This level of risk justifies serious consideration for shutting down the plant. Renewable energy sources would provide safer alternatives to this threat.
* Al Gedicks is executive secretary of the Wisconsin Resources Protection Council in La Crosse. This report was first published in La Crosse Tribune as ‘Nuclear Safety Must be Focus’, Aug. 31, 2022