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MidAmerican Energy seeks Iowa approval to study new nuclear power plant technology

  • Mar 16, 2022

Mar. 16—Nuclear energy hasn't been generated in Iowa since the August 2020 derecho shut down the Duane Arnold Energy Center near Palo.

But gaining attention is a new type of nuclear power plant — smaller, modular and designed to be safer in power outages. Iowa utilities are watching pilot projects involving them in other states, and MidAmerican Energy wants to invest in a study here of new nuclear technology.

"We would like to study small modular reactors as one of several potential avenues to help us achieve net zero greenhouse gas emissions," MidAmerican spokesman Geoff Greenwood said in an email.

MidAmerican, based in Des Moines, has asked the Iowa Utilities Board for permission to launch a $3.9 billion Wind PRIME project that would include wind and solar energy projects as well as study of three "emerging and innovative carbon-free technologies": energy storage, carbon dioxide capture and a small modular nuclear power generation.

Energy storage and nuclear generation would be ways to maintain steady power when the weather doesn't allow wind or solar generation. Carbon capture seeks to store the CO2 greenhouse gas from industrial processes permanently underground.

"At this very early stage MidAmerican is simply asking the Iowa Utilities Board to authorize us to spend the necessary resources to study these three areas," Greenwood said. "It's the first step in determining if any of them would be feasible. It is not a commitment to utilize one over another or any at all."

MidAmerican asked the board to decide by Oct. 31 on the project, which could affect customers' electrical rates.

Since the 1950s, U.S. utilities have been using nuclear power to generate electricity. These older plants — many of which are still in use across the country — use nuclear fission (with uranium atoms in most cases) to heat water, which produces steam that spins large turbines that generate electricity.

Nuclear reactors produce lots of energy without the environmental toll of fossil fuels, but traditional reactors are very expensive to build, can be dangerous if there's a power outage and the nuclear process produces radioactive waste.

The Duane Arnold plant near Palo, which began operating in 1975, was set to be decommissioned in October 2020. But the Aug. 10, 2020, derecho caused damage to the plant and so it closed permanently about three months early.

Next door to Iowa, Tom Kent, president and chief executive officer at Nebraska Public Power District, has been working with nuclear energy since he was in the Navy, which uses nuclear energy to power submarines and ships.

The district operates the Cooper Nuclear Station at Brownville, Neb., about 20 miles southwest of Iowa's southern border.

"The resource mix to our customers today is 65 percent carbon free and a big chunk of that is due to our nuclear portfolio," Kent said in an interview.

The utility plans to operate Cooper until the plant's license expires in 2034, then will consider whether to apply to renew that license, Kent said. The district is watching the development of new nuclear projects elsewhere.

"We see and are excited by opportunities with advanced nuclear (and) modular reactors and we're watching that very closely," he said. "We'll also compare that (Cooper performance) with the newer nuclear tech and make decisions and recommendations based on what we think is the best path forward to ensure the economic and reliable operation of our facilities and continued reduction of our carbon footprint over time."

Kent said some of the ways new nuclear technology is different from traditional nuclear include:

— Smaller, modular reactors that are cheaper to build, often in factories off site.

— Passive, physics-based water cooling systems rather than pumps and motors. If there's a power outage due to a storm or otherwise, the reactor could still continue cooling rather than have heat rise to a dangerous level.

— Some plants use liquid sodium rather than water for cooling. Since sodium is a heavier element, the neutrons don't slow down as much. These "fast reactors" may be able to extract more power from uranium, reducing the amount and toxicity of the waste.

There are several new nuclear projects underway in western states.

TerraPower, founded by Bill Gates and connected with a subsidiary of Berkshire Hathaway — which also owns MidAmerican — is building the Natrium reactor in Kemmerer, Wy. This facility, to be opened in the "late 2020s," includes a sodium fast reactor coupled with a molten salt-based energy storage system, according to the company's website.

To cut costs, the bulk of the Natrium reactor could be built off site without the need for nuclear regulatory approval. The passive vessel cooling system will reduce space and the amount of nuclear-grade concrete needed, the website says.

Also, the U.S. Department of Energy is working with the Utah Associated Municipal Power Systems and NuScale Power to build the Joint Use Modular Plant in the desert west of Idaho Falls, Idaho. The project would use smaller pressurized water reactors relying on natural convection instead of pumps, the reported in 2019.

That project was proposed with 12 reactors, but now has been scaled back to six with a cost of $5.1 billion, the Seattle Times reported in November. Design changes and other delays have pushed the projected opening date to 2029.

X-energy, based in Maryland, has proposed building a $2.2 billion four-reactor project in Washington state by 2028, the Times reported. Developers plan to use a helium gas-cooled reactor, a technology developed decades ago but not used widely in the United States.

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