Can aging plants be disposed of safely? SCRAPPING OLD NUKES

ITS appearance belies the historical significance. Nestled along the leafy banks of the Ohio River, the Shippingport Atomic Power Station is a drab series of cinder-block and rust-tinted buildings, shadowed by an Erector Set of transmission lines.

When the plant was switched on in 1957, though, it was considered a milestone in the quest to harness the atom for peaceful uses. It was the nation's first commercial nuclear reactor. During groundbreaking, President Eisenhower decreed that the plant in the rumpled hills of western Pennsylvania would bring mankind ``closer to fulfillment of the ancient dream of a new and better earth.''

Today, the small Shippingport reactor is again playing a role in energy history. Over the next five years, a special demolition team will tear down the now-defunct facility 25 miles from Pittsburgh, beam by beam, to the bare earth and bury the remnants at a nuclear waste dump across the country.

It will be the largest nuclear reactor in the world to be dismantled to date -- and one the United States Department of Energy (DOE), the project steward, hopes will serve as a test for how to ``retire'' reactors safely.

Disposing of the radioactive scrap from the first quarter-century of the atomic age is quietly emerging as one of the next big challenges on the nuclear horizon. Coping with a growing stock of aging power plants is the most pressing task ahead. At least 15 of the more than 80 licensed commercial reactors in the United States today may become candidates for decommissioning, as it's called, by the year 2000. DOE estimates that 50 more may be eligible by 2010. How well the nuclear industry deals with these reactors could well help shape its image in the next century.

But these are only part of the nation's radioactive inventory. Dozens of small research reactors may also be candidates for decommissioning soon, as well as an abandoned nuclear waste reprocessing plant in West Valley, N.Y. Some two dozen contaminated sites remain to be cleaned up from work on the Manhattan Project, and DOE owns another 353 facilities that will have to be decommissioned at some point. A similar fate awaits 10 mothballed nuclear submarines. Worldwide dimensions

Worldwide, the International Atomic Energy Agency in Vienna estimates that about 100 large nuclear plants could be shut down by the year 2000. Several small pilot projects are already under way overseas. Britain, for instance, is working on the 33-megawatt (mw.) Windscale plant in the northwest part of the country. The French and Japanese are pursuing new robotics and other technologies that will aid workers in contaminated areas.

``It [decommissioning] is a global problem,'' says Dr. Carl Feldman, a member of the decommissioning staff of the Nuclear Regulatory Commission (NRC).

In the US, the nuclear industry generally sees power plant decommissioning as a straightforward engineering task that should not prove too costly. But nuclear critics contend it could ratchet up consumers' utility bills and pose health risks.

Experience with decommissioning in the US has been limited so far to a few test reactors and commercial plants much smaller than Shippingport. Thus the reason that work on the 72-mw. reactor here -- even though not all the lessons will be transferable to today's bigger plants (usually 1,000 mw. or more) -- is under the microscope.

``Everyone is watching Shippingport closely,'' says Daniel Williams, an Arkansas Power & Light Company engineer, who sits on three industry-backed groups looking at decommissioning.

Like any other industrial equipment, nuclear power plants eventually wear out. Some upgrading can be done. But eventually it becomes more economical to close a plant down than to replace corroded pipes, valves, pumps, and embrittled metal, weakened in part by the radiation itself.

Unlike conventional equipment, though, the plants can't simply be abandoned or razed and forgotten. Over time, radioactivity becomes embedded in a plant's steel-and-concrete skeleton. So even after the uranium fuel rods are removed, some parts have to be isolated from the public for hundreds of years.

A nuclear plant is generally assumed to have a 30-year operating life, which is about the time the NRC licenses it for. But utilities are beginning to look for ways of extending the life of plants. If successful, this would alter the number of ``nuclear tombstones'' the industry will have to deal with in the near term.

On the other hand, maintenance and structural problems, as well as the task of retrofitting to meet new regulations, can shorten lives. Besides Shippingport, three other reactors are now ``retired'' and await decommissioning: Humboldt Bay in California (after 13 years running), Indian Point 1 in New York (after 12), and Dresden 1 in Illinois (after 18).

Plants can be decommissioned several ways. One is entombment, encasing them in concrete and allowing the plants to sit for years while some radiation subsides. Another is mothballing, fencing sites off and guarding them for a period. The third is immediate razing, as at Shippingport.

Razing is probably the most politically acceptable. But in the short run mothballing and entombment are cheaper because they require little up-front money and put off the time when the plant is to be torn down. Some utilities prefer these methods, too, because dismantling a plant is safer after a cooling-off period. Waiting also gives the country more time to work out the problem of where to store its high- and low-level radioactive garbage -- which could, even some industry officials admit, become a snag if new burial sites weren't eventually found.

``We're talking about unconventional volumes of low-level waste,'' says Arkansas Power's Mr. Williams. ``It is something that deserves a little planning in advance.''

Certain plants are already stirring controversy. Pacific Gas & Electric Company, for instance, wants to mothball its Humboldt Bay plant in northern California for several decades for many of these reasons. But some citizen groups and environmentalists worry about storing a dead reactor close to two geological faults. They want it torn down.

The most contentious point surrounding nuclear ``undertaking,'' however, is the cost. Studies done for the industry indicate dismantling commercial reactors that haven't been mothballed or entombed should range from $80 million to $200 million (in 1984 dollars). DOE has budgeted $98 million for Shippingport -- about 12 percent of the cost of building it today.

``It's a rather small part of the cost of building a plant,'' says Keith Steyer, chief of the chemical engineering branch of the NRC's nuclear regulatory research office, speaking of the general numbers.

But tabs will vary greatly from site to site, depending on such things as how much radioactivity is left in a plant. ``The cost is still a big unknown,'' says Barry Abramson, senior utility analyst with Prudential-Bache Securities Inc., the brokerage firm.

The NRC has just come out with proposed rules for tearing down reactors. These will require, among other things, that utilities stipulate at the time they receive their operating licenses how they plan to finance decommissioning.

Many utilities already have begun to set aside trust funds for the task, financed by a small charge in consumers' electric bills. But critics charge the industry underestimates the economics of the process and that it may lead to ``rate shocks'' later on.

``When the industry holds up nuclear power as a cheap source of electricity, this is one of the costs they're not calculating,'' says Paul Markowitz, an analyst with the Critical Mass Energy Project, a group that backs alternatives to nuclear power.

One other bone of contention is that, under the NRC's proposed rules, utilities would have the option of setting up ``internal'' trust funds to bankroll decommissioning. This means they could use the money while it was accumulating for other capital outlays. Nuclear opponents worry the money won't be there when it comes time to raze -- a charge the industry pooh-poohs.

The Shippingport plant sits on seven acres amid one of the country's most heavily industrialized river valleys -- a sort of Ruhr Valley for electricity. On one side loom the modern hourglass-shaped cooling towers of the Beaver Valley 1 and 2 nuclear reactors, operated by Duquesne Light Company. Farther off lie the pencil-like stacks of a coal-fired facility.

Shippingport sits on land owned by Duquesne but which DOE, owner and operator of the reactor since the 1950s, leases. Demolition work at the site won't begin until September. Using chemical solutions and high-pressure hoses, workers will start flushing superficial contamination off interior walls. Power saws and torches will be put to some of the plant's 21 miles of piping. Crews have already removed the highly radioactive fuel rods from the reactor core, which were taken by rail to a government laboratory in Idaho. Biggest lesson: shielding workers from radiation

Shippingport is far less radioactive than most plants today. Because it was a demonstration project, it received special care and was decontaminated once before, when work was done on the reactor core. This raises some questions about how much of the information gleaned here can be applied to bigger plants.

``Ideally, from the standpoint of expense, we need to dismantle a large base-load reactor,'' says Sally Hindman, executive director of the Maryland Public Interest Research Group, a consumer group.

DOE officials contend, however, that the basic techniques can be applied on any scale. This includes the managerial and planning aspects of such a task. Perhaps the biggest lesson they see, though, will be in protecting workers from radiation exposure.

``If you have something that's contaminated, you go through all the same practices no matter what the level of radioactivity,'' says John Schreiber, DOE's project manager. ``How you take the plant down, store it, and ship it -- these types of things will all be shared.'' From Pennsylvania to Oregon -- via Panama

Precautions will be tight. In some ``hot'' areas, remote-control tooling or robotics may be enlisted. Plastic enclosures will be put around work areas. Some tools will have to be buried after use. Water will be sprayed over areas to settle radioactive dust. For certain chores, workers will wear yellow ``moon suits.''

``We've done all aspects of the process of decommissioning before,'' says George Gans Jr. of Burns & Roe Industrial Services Corporation, a New Jersey-based engineering firm that planned the project. ``But what has not been done is a sizable nuclear plant in total. That's what Shippingport is.''

The toughest task will be the removal of the reactor vessel itself, which will be done in one piece. The 33-foot-high steel hulk will be encased in three feet of concrete to shield workers from radiation. Then, sometime in 1989, the 770-ton behemoth will be lifted by a specially built crane and shuttled to a nearby barge. From there, it will be shipped down the Ohio and Mississippi Rivers, through the Gulf of Mexico and the Panama Canal, and up the West Coast to Washington State. The barge will steam inland on the Columbia River to a federal burial site at Hanford, Wash. There, amid a sprawling expanse of sagebrush, the vessel will be buried beneath 30 feet of earth.

Project officials will have to get a passel of permits from states and countries to transport the material along its circuitous route -- a task likely to draw some opposition from groups concerned about transporting hazardous cargoes. But shipping the reactor whole, DOE officials says, will reduce worker exposure to radiation and eliminate the need to transport 80 truckloads of waste across country. Some materials, though, will still be trucked or taken by rail.

Critics point out that today's reactor vessels won't be able to be shipped in bulk but will have to be cut up -- a riskier and more costly proposition. Others contend that the process of shipping the containers whole may be used on some reactors and that the project will be instructive anyway on everything from verifying cost estimates to determining crew sizes.

The site is expected to be returned to its original contours and sodded by 1990. For now, federal officials are taking painstaking precautions in all aspects of the Shippingport project. They know that, like the dedication of the plant 27 years ago, engineering feats can carry larger symbolism.

``It's more of a political project than an energy project,'' says Kenneth Eger, a safety and environment manager with the General Electric Company, a contractor on the project. ``We know how to do it. But it has never been done before, so it has to be proven.''