Jan 14, 2020

Sandia Labs Helps Arizona Power Plant Reduce Water Use & Costs

Researchers at Sandia National Laboratories are working with the Palo Verde Nuclear Generating Station to reduce water use and costs to generate electric power.

power plant

The researchers developed a model to track the water and gauge water quality at the power plant, located near Phoenix, Arizona, which converts heat from nuclear reactions into electricity. 

The power plant is in an area where water is scarce, according to the Albuquerque Journal.

 “We are looking at how much water they are using, the chemicals being used in the treatment and the cost,” said Bobby Middleton, a nuclear engineer at Sandia. “We are trying to help them make adjustments to save money and water.”

In 2019, the Arizona Legislature adopted a drought contingency plan, which trimmed the state’s annual allotment of Colorado River water by about 7% to maintain levels in river reservoirs. Lawmakers have expressed concern about the overpumping of water and depletion of aquifers, reported the Albuquerque Journal.

Palo Verde’s cooling water is treated wastewater, which is becoming increasingly expensive. To curb these rising costs, operators want to reduce the plant’s water use by about 9 million gallons a day, according to the Albuquerque Journal.

The wastewater that arrives at Palo Verde contains silica, calcium, magnesium and phosphate ions. These salts concentrate as the cooling water evaporates in the cooling system, sometimes forming new minerals that might clog the cooling towers. Currently, operators add lime, soda ash and acid to the wastewater before it enters the cooling tower to reduce mineral formation, reported the Albuquerque Journal.

The model is being used to identify less expensive ways to remove ions at different points in the cooling cycle, according to the researchers.

Middleton and Sandia chemist Patrick Brady believe their analysis can be applied at nuclear plants across the country. The researchers believe that analysis could be used to save water at these power plants and they intend to consult with other power plants during the process.

The researchers also redesigned and patented an air cooling system to make waterless cooling more energy-efficient and possible over a wider range of operating conditions. If the Department of Energy approves funding, the prototype could be operational in a little more than two years, and the system itself by the mid-2020s, reported the Albuquerque Journal.

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