Reactors` Revival Still Must Wait

April 30, 1989|By Stevenson Swanson.

Although some of the gloom is gone in the world of nuclear power, the scene at an electric utility conference in Chicago last week was not exactly jubilant.

Concerns about a possible greenhouse effect have spurred hopes for a revival of nuclear power, but the industry is not positioned well to take advantage of any shift in public opinion. A new generation of safer, more efficient nuclear reactors probably will not be built in this century, industry executives believe.

Designs for advanced nuclear reactors still must be completed, tested and certified by the Nuclear Regulatory Commission, experts noted.

The commission is revamping its expensive and lengthy licensing procedure, which brought the nuclear industry almost to a standstill even before the accident at Three Mile Island in 1979 generated widespread opposition to nuclear plants.

Then some utility has to place the first order for a new nuclear plant, a move that seems likely to draw wide publicity and bring back to a boil the simmering debate about nuclear power.

``There is a greater feeling of optimism,`` said Richard Valentin, a top scientist in an advanced reactor project at Argonne National Laboratory. ``But there`s a lag time between optimism and program development, and no one is going to shower anybody with billions of dollars based on optimism alone.``

Nuclear energy is getting new looks from legislators and even some environmentalists because of fears of a greenhouse global warming. Fossil-fuel power plants emit carbon dioxide, the alleged greenhouse effect culprit, while nuclear plants do not.

But the new types of reactors that are intended to erase the public perception that nuclear power is dangerous are still far from commercially viable.

``I don`t think nuclear energy should be seen as the answer,`` Valentin said. ``The greenhouse effect is forcing people to look at all the things that are causing temperature changes. It`s hard to pick an industry like this one and say the greenhouse effect is good for this industry or bad for that one.`` Of the main types of advanced reactors on the drawing boards, redesigned versions of existing plants are the closest to being ready for construction, according to industry executives who attended the American Power Conference at the Palmer House.

A standardized General Electric model might be certified by the Nuclear Regulatory Commission in 1991. A standard design by Combustion Engineering might be approved in 1992. The utility industry has been demanding

standardized designs to keep costs down and improve safety.

But these reactors would be about the same size as the newest existing reactors-900 to 1,300 megawatts-and, because most of the country has enough generating capacity, some executives see the designs mainly as ways to test methods of standardization and a streamlined certification process.

Engineers at G.E. and Westinghouse are working on smaller, standardized reactors that could be built in modules to reach a desired power level. These are the most likely to be built next in this country, Valentin and others believe, but their designs probably will not be certified before the mid-1990s.

The large and the smaller standard designs are meant to incorporate the lessons of the last three decades, including those learned at the Three Mile Island accident in 1979 and in less threatening incidents. Of prime concern is the need to make safety systems ``passive`` and reactors ``inherently safe,`` as the industry puts it.

Problems arise at existing plants because of their complexity and because operators have to initiate the plants` response to breakdowns. Then those safety systems have to work properly. If, however, a plant`s design takes advantage of gravity-for instance, by placing an emergency reservoir of 400,000 gallons of water above the reactor core-the margin for failure or human operator error should be reduced.

Two types of radically different reactors are also under design, but they will not be ready for commercial use until the next century. One being developed by Argonne uses liquid sodium to transmit heat from the reactor core to a steam generator, which powers the plant`s turbines.

In a test in Idaho last year, a liquid-metal reactor was disabled, and its safety mechanisms were shut down. But instead of melting down and releasing radioactivity, the reactor core shut itself down.

The design is called ``inherently safe`` because of its unusual uranium-plutonium-zirconium fuel, according to Valentin, who is working on

development of the fuel at Argonne. G.E. is leading a consortium of high-technology companies that are designing a plant to house the reactor.

Another design under development by the U.S. Department of Energy and General Atomics of San Diego would use ceramic-coated pellets of uranium as fuel and helium as the heat-transferring medium. These features, plus a maximum plant capacity of only 140 megawatts, would prevent the core from melting, its advocates say.

But every type of advanced reactor has real or potential critics. Standardized reactors still use water as a coolant, which some say cannot be made completely safe.

And the liquid-metal reactor ``breeds`` more fuel than it consumes, an issue that derailed breeders in the late 1970s because of fears that terrorists could steal the new fuel and make nuclear weapons.