It may seem a mere tangle of pipes and instruments to the untrained eye. To nuclear engineer Jose Reyes, it's a sign of a coming nuclear-power plant revival in the United States with electricity produced more safely and for less money than the atomic behemoths built in the 20th century.

This jumble of technology is a one-quarter-scale model of the Westinghouse AP1000 power plant. Reyes heads a team at Oregon State University that built the model to test the AP1000's so-called passive safety systems, under contract with the U.S. Department of Energy and Westinghouse.

This kind of safety system, Reyes said, would make nuclear leaks far less likely, and virtually eliminate the threat of a meltdown of the nuclear core.

The partial meltdown of the Three Mile Island nuclear plant in Pennsylvania in 1979 helped lead to a virtual halt in new plant construction along with high costs and energy demand forecasts that turned out to be wrong.

But global warming and the rising cost of natural gas and coal may finally change the image and the appeal of nuclear power as the industry markets a new generation of reactors, such as the AP1000 and General Electric's ESBWR, or Economic Simplified Boiling Water Reactor.

Interest in new plants has increased sharply since last August, when President Bush signed an energy bill that streamlines applications and offers loan incentives, tax credits and federal insurance for new plants. Licensing could be approved within a few years, depending on when applications are filed with the Nuclear Regulatory Commission.

But there are plenty of skeptics. They point out that, because the AP1000 and ESBRW have not yet been built, it's still uncertain how much they will cost or how safe they will actually be.

"It's been tested in scale models,'' David Lochbaum, director of a nuclear safety project for the Union of Concerned Scientists, said of the passive-safety system.

"If there's a gap between'' testing and what happens when such designs are put into operation, "it could be a nasty surprise,'' said Lochbaum.

Over the past decade Reyes' team at Oregon State University has played an important role in charting the future of nuclear power in this country.

The model uses no fissionable material. Instead, electricity heats water to temperatures reached in a nuclear plant, and the water is moved through the model, testing each of the safety features.

The cooling system in the previous generation of reactors operated much like a car radiator, requiring constant pumping of cool water to prevent overheating.

In the passive safety designs, the cooling system is more like the tank of a bathroom toilet. Flip a single handle and cool water rushes down to the reactor if it overheats. Designers say that if the operator needs to leave the plant during an accident, that handle will be tripped automatically, and the reactor will cool itself.

The passive safety system also contributes to making this generation of power plant less expensive to build because there are far fewer parts, nuclear advocates say. The system eliminates the need for huge cooling towers, redundant pumps and backup diesel generators.

The next generation of nuclear power plants will not only be safer than the previous generation, but also simpler, more streamlined, and therefore far less costly to build than reactors now online, nuclear engineers say.

The AP1000, according to Westinghouse, has 87 percent less cable, 83 percent less piping, 50 percent fewer valves and 36 percent fewer pumps than the previous generation of reactors.

The new General Electric design the ESBWR is similar to the AP1000. Both use simplified construction that dramatically shrink the size of the power plant as well as passive safety technology.

General Electric has been racing with Westinghouse now owned by Toshiba Corp. and other manufacturers, such as Areva NP in France, to build the next generation of nuclear reactors.

Estimates on the cost of new reactors vary widely, and it is difficult to compare current costs with past projects that required years to build and many design modifications, analysts say.

The best measurement is how much it will cost per kilowatt of electricity to build a new plant, said Per Peterson, a nuclear engineer at the University of California, Berkeley.

New coal plants with carbon scrubbers cost about $1,800 per kilowatt, said Adrian Heymer, a financial analyst for the Nuclear Energy Institute.

Second-generation nuclear plants from the 1970s ranged in cost from $600 to $3,700 per kilowatt, depending on a wide variety of factors, Heyman said.

"But it's very hard to translate those numbers to current numbers, partly because they were all custom designs, with custom modifications,'' Heyman said.

Nuclear opponents say that even if the new safety features work under all conditions, there's yet another problem to be resolved: as of yet, the United States has no permanent storage facility for spent nuclear fuel.

But nuclear opponents are telling people not to get their hopes up. Among them is Portland attorney Greg Kafoury, a veteran of battles against atomic power in the Pacific Northwest.

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