Capstone class gives students nuclear plant experience

Students Andy Smolinski (left) and Liz Young with new reactor director Bob Agasie. (33K JPG)

Hoping to solve a long-term Madison and university energy crunch, electrical utility companies, the university and Wisconsin's Department of Administration proposed last December to build a 90- to 100-megawatt natural-gas-fired power facility on the western edge of the UW-Madison campus.

This summer, a couple of nuclear engineering undergraduate students designed a nuclear power plant that, in theory, could fill the same shoes.

Students Andy Smolinski and Liz Young devised a 100-megawatt, scaled-down version of a simplified boiling water reactor (BWR). In this type of reactor, water circulates through the pressure vessel, which houses the reactor core. In the core, the fuel and water work together: Water keeps the fuel from getting too hot, while the fuel heats the water to boiling and turns some of it into steam. As the steam rises, it flows through turbines and eventually into generators. After that, a condenser recycles the steam into water and the process begins again. Since the system is self-contained and driven by natural circulation, there are no water circulation pumps, reducing the risk for a loss-of-flow accident. "In old designs, you have extraction water being pumped through jet pumps and back in through external loops," says Young. "There are safety implications there, because if you get a break in that, suddenly you have water going all over the place. You don't want to overheat the fuel."

The pair's design incorporated other safety features as well. The plant's containment building, which houses the fuel source, is set completely below ground. Smolinski and Young also devised "spare" water tanks with valves held closed only by the primary system's pressure. "Should you get a loss of coolant — say a break in one of your main pipes — your pressure is going to decrease," says Smolinski. "The moment that pressure decreases, it opens that gate and starts flooding the core."

Similarly, the design includes a giant pool of water that sits atop the containment building. That reserve can cool the core or containment building in an emergency.

Smolinski and Young created their design for Nuclear Reactor Design , NE (NEEP) 412, an eight-week capstone course for nuclear engineering undergraduates held last summer. "The goal of the class is for students to design a nuclear system on their own, with minimal input from the instructor and drawing upon the other classes they have taken as undergraduates," says Associate Professor Robert Witt, the course's instructor.

They definitely drew on past knowledge. "I think I was carrying around seven textbooks or something like that," says Smolinski. "I had a 5-inch binder that I filled." For his research, he also toted a couple of 3-inch binders that contained a safety-analysis report from the now-decommissioned 50-megawatt LaCrosse, Wisconsin, BWR. Both students each spent at least eight hours a day — and more time as their deadline neared — working on the project.

In addition to their plant design, this year Nuclear Reactor Design students also had to research locations at which their plants could be sited. After ruling out spots near Milwaukee, on the Mississippi River and on the Wisconsin River, Smolinski and Young chose Lake Koshkonong where Dane, Rock and Jefferson counties meet. The two considered several factors, including environmental impact, plant positioning, lake use and population, proximity to Madison, and proximity of rail lines and transportation routes, before deciding on a locale near the 10,460-acre man-made lake. "In the '70s, they were actually thinking about siting a plant there," says Young.

For the students' plant, Professor Michael Corradini, encouraged Smolinski and Young to "think small." Today, governmental agencies are exploring the possibility of nuclear reactors that are smaller, safer and more economical, hold minimal proliferation risks and generate less waste, he says. "In the next generation of such power plants, small power plants (less than 500 megawatts electric) would be of interest," says Corradini. In addition, he suggested they attempt a BWR, given the LaCrosse reactor's record for safety and reliability.

Since the two based their scaled-down design on existing technology (among its products, GE Power Systems makes both simplified and advanced boiling water reactors), the technology should be familiar to utilities, says Witt. "It is reasonable to expect that such a system, if deployed, could be operated at the very high capacity factors the industry is already enjoying," he says.

But though Smolinski and Young, now graduate students in nuclear engineering, received an "A" on the project, they won't be submitting their design for construction anytime soon. "It's a working concept," says Smolinski. "As for being built, it would need a lot more work."