Kewaunee Nuclear Power Plant. (Photo: Kewaunee Nuclear Power Plant Nuclear Management Company) (39K JPG)

In a normal year, the Kewaunee Nuclear Power Plant generates about four billion kilowatt-hours of electricity for the customers of its owners, Wisconsin Public Service and Alliant Energy.

And in an industry where efficiency in production is key, it's impractical to take the plant or specific systems off-line while workers analyze how the systems function under various conditions. "We've got to do the analysis with computer models," says John Holly, principal engineer in thermal hydraulic analysis for Nuclear Management Company, which operates the Kewaunee plant.

For several years, Kewaunee technical have learned more about how the plant's systems perform under a range of operational conditions. By developing computer models of some of those systems, UW-Madison faculty, staff and students have played a role in that process, he says.

Most recently, Andy Smolinski, who earned a 2002 master's degree in nuclear engineering from the Department of Engineering Physics, modeled the plant's component cooling water system for his master's thesis.

In a nuclear power plant, the component cooling water system acts like a buffer zone between the system that cools the reactor and the system that touches the environment. It consists, loosely, of heat exchangers, pumps, valves and a closed-loop piping system. "It is an important system as far as ultimate cooling of the plant following an accident, so it is one of our critical safeguard systems," says Holly.

To develop the computer model, Smolinski examined nearly 50 plant design drawings to determine the exact sizes of some-400 elements of the component cooling water system. He entered that data into a computer model called ProtoFlo and engineering physics researcher John Murphy double-checked his calculations and data.

Working with NMC senior mechanical engineer Ray Berzins, the two benchmarked the finished model against physical conditions in the plant. "We would run the code and then they would compare it to tests they had run," says Murphy.

The model's outcomes matched the actual test results, confirming its accuracy, says Berzins. "And so if you apply the models, it's easy to calculate different scenarios," he says. "You shut off a loop and now you see exactly what's going on, or you have two pumps versus one pump. It's an easier method of calculating. The hand calculations are nearly impossible."

The project couldn't have occurred at a better time, says Holly. In 2002, a faulty heat exchanger in the component cooling water system forced a plant shutdown. Later in the year, questions arose about a certain system configuration and its effect on cooling capability. So when inspectors from the Nuclear Regulatory Commission (NRC) visited Kewaunee, they focused on the component cooling water system.

"What Andy created was actually used to help answer a number of the NRC questions," says Holly. Kewaunee staff used the model to simulate specific accident conditions and determine how the system would function. "We answered those kinds of questions using the model-and I think that was a positive from the NRC's point of view," he says.

The department's close relationship with the state's utilities benefits the students as well, says Engineering Physics Professor and Chair Michael Corradini. "It's the perfect sort of work to train nuclear engineers about the industry, because they really get their hands into the system," he says. "Andy had to worry about pretty nitty-gritty details. It's exactly what engineering is all about in the real world. And with master's students, that's the sort of training we want."

Contact: John Murphy
608/265-4186