Palisades nuclear plant critics vow to continue fight over ‘thermal shock’ issue via SNL

By Matthew Bandyk

Another bout between federal regulators and environmental groups over Entergy Corp.’s Palisades nuclear plant is beginning, with the opposition to the plant saying unearthed information reinforces the case that the facility on Lake Michigan needs complicated and unprecedented upgrades to be able to operate safely.

The next round of protests against Palisades, which has been subject to fines and Nuclear Regulatory Commission investigations due to performance problems appearing intermittently over several decades, is happening in the aftermath of an NRC decision.

The agency denied a hearing into whether the reactor pressure vessel at Palisades had been “embrittled” by radiation exposure over the course of its over-40-year life. Beyond Nuclear, an anti-nuclear group that demanded the hearing, argued that the Palisades reactor is at risk for a “pressurized thermal shock event,” in which the temperature differential from cooling the reactor could cause the weakened reactor vessel to breach.

Starting in the 1980s, Russian nuclear plant operators wanted to get more years out of several reactors that had embrittlement problems. Ultimately, the reactors were able to keep running thanks to a mechanical engineering process called annealing, in which the vessel is heated up to as high as about 1,800 degrees Fahrenheit, and then, after cooling, the steel is able to recover the toughness lost from years of radiation exposure.

Fixing the problem has proven to be herculean in the past. The Yankee Rowe plant in western Massachusetts, one of the earliest nuclear plants built in the U.S., retired in the early 1990s after the NRC concluded the reactor’s neutron embrittlement was so severe that the reactor had to be shut down until the issue could be resolved. The owner, Yankee Atomic Electric Co., had examined annealing as an option to restore the reactor but ultimately decided the cost of testing for cracks was too high due to unique design elements of the reactor vessel.

Aging issues have rarely been more important for the nuclear industry. The amount of nuclear capacity in the country could fall off a cliff over the next few decades if federal regulators do not allow nuclear plants to run beyond the current licensed limit of 60 years of operation. The industry is gearing up for the arduous regulatory process that will be required to convince the NRC that 80 years can be achieved safely.


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