Palisades draws its cooling water from the lake, but global warming means that the lake's bulk temperature - like the rest of the world's water reservoirs - has been increasing, and is expected to continue rising in the coming decades during its projected service life, Holtec said.
To meet the projected water temperature increase, the new unit needed to be more than twice as large in heat transfer surface area as the existing unit, but had to fit in the same space, which presented challenges for the system's developers.
"It was like asking to put two gallons of milk in a one-gallon carton," said Edward Bell, Director of Holtec's Heat Transfer Division.
The innovative design means the cooling system upgrade will require very little civil/structural work, which may reduce the project cost by more than 50% compared with the initial projection, the company said. The heat exchanger system is being manufactured at Holtec's fabrication plant in Pittsburgh, Pennsylvania.
Palisades was shut down in 2022, and was to be decommissioned. Holtec is now working to bring the 800 MWe pressurised water reactor back into service, aiming to repower it by the end of 2025. It would be the first nuclear power plant in the USA to return to commercial operations after being closed down, and current plans would see it provide baseload clean power until at least 2051.
