In the scariest scenarios of nuclear waste transportation disasters, catastrophe unfolds like any highway accident. It begins with an icy bridge, or some Beltway motorist who brakes for animals. It ends in scenes of evacuated cities and invisible contaminants riding the wind.

No such event has ever come to pass on the nation's highways in more than 30 years of shipping nuclear materials around the nation.

But in Maryland alone, nuclear waste and other radioactive materials are shipped every day. The state Department of Health and Hygiene counts approximately 80 truckloads a month of radioactive material.

The bulk of the waste is low-level. Although some of it can have a high level of radioactivity, it is, as atomic waste goes, generally less hazardous, ranging from contaminated gloves, pieces of reactor cores to the more macabre medical cargoes such as 55-gallon drums of dead, irradiated rats.

On the other end of the scale lies high-level waste, including spent fuel rods from nuclear power plants, the most radioactive material on the road. Spent fuel, millions of times more radioactive than fresh fuel, travels on highways in huge lead-lined casks that can weigh more than 40 tons and are licensed by the Nuclear Regulatory Commission.

How to store, move and keep people clear of nuclear waste is not the most visible nuclear issue. But concern over the safety of nuclear waste transportation, compounded by a lack of information, has spurred states and municipalities to ban or regulate the shipment of large amounts of irradiated material, starting with New York City in 1976.

About 182 jurisdictions have passed outright bans. Another 211 jurisdictions, including Prince George's County, require advance notice of shipments. A similar proposal is before the Montgomery County Council.

But after four months with a prenotification law in effect, Prince George's officials still don't have any idea what's on their roads. "Would that we did," said R. Hal Silvers, the director of the county's Office of Emergency Preparedness. "Shippers are continuing to violate Prince George's edict."

A group of state agencies has recommended routes for shipping spent fuel and other "large quantity" radioactive material through Maryland, including the Capital Beltway, Interstates 70, 81, 83, 95 and 270, Rtes. 301, 4 and 48, and sections of the Baltimore Beltway. The recommendations were passed by the legislature this year and await Gov. Harry B. Hughes' signature.

Interstate 81, which jogs for a dozen miles across Western Maryland, is a major route for traffic between the Chalk River experimental reactor in Ontario and the U.S. government storage facility at Savannah River. Maryland Health Department officials, who are obliged to handle a radioactive accident, say they do not know precisely how much spent fuel was shipped through the state last year on I-81.

Virginia, which keeps better records, logged the number of spent fuel shipments on I-81 at two in 1981.

Virginia's Bureau of Radiological Health also recorded six shipments of "large quantity" radioactive material--cobalt 60 isotopes used for medical therapy--that were transported on I-495 and I-95, and two others that were hauled just on I-95. (The packages that contain large-quantity radioactive materials have to be able to meet the same fire-and-crash standards as spent fuel casks do.)

In Maryland, aside from I-81, the Nuclear Regulatory Commission, which in the past has determined routes for shipments of bomb grade commerial material (primarily spent fuel), has designated Rtes. 4 and 301 for shipments from the Calvert Cliffs nuclear power plant. The plant occasionally has dispatched spent fuel rods for research purposes.

Very little spent fuel is moving now in the United States. Most of the it is being stored in pools of water on the sites of 75 nuclear plants around the country. But those pools are filling up and Virginia Electric and Power Co. says it could run out of storage space at its plant in Surry as soon as 1985.

A draft report by the National Academy of Sciences predicted last fall that in two decades more spent fuel will be in transit each day on the nation's highways than was moved in all of 1980 when there were 108 shipments. The report forecasts an yearly volume of 9,000 shipments by 2004.

All this has intensified the controversy that surrounds the transportation of nuclear waste. Statistically, trucks hauling liquid natural gas, chlorine, gasoline and other toxic chemicals present greater risks than the trucks carrying spent fuel. The U.S. Department of Transportation has said the radiation danger from these shipments is of such slight hazard that it would produce no more than one case of cancer in 25 billion years.

Yet radioactive waste holds some Frankensteinish horror that arouses deep emotions. When federal transportation officials held a public hearing last year in New York on the proposed preemption rule, the crowd got so wrought up that police had to escort the officials to safety.

In February, a New York federal judge temporarily blocked the federal regulation that would have overturned New York City's and other municipalities' bans on shipments of spent fuel and other highly radioactive substances. That case is still unresolved.

Aside from the federal-state issues, safety concerns were underscored in a study released earlier this year by the Council on Economic Priorities in New York. The report was particular critical of the integrity of the casks that hold spent fuel.

"It's not peanut butter the casks are carrying," said Marvin Resnikoff, a nuclear physicist at the council. "Each truck cask contains 10 times the amount of radioactive cesium as in the Hiroshima bomb. We're not concerned with the cask walls breaching. They're thicker than the walls of a submarine. But there are much more likely accidents that could happen that have not been quantified."

Activists seeking to demonstrate the lackadaiscal attitude toward radioactive shipments have driven through suburbs with loads falsely marked as radioactive. They have released black balloons to graph the drift of contaminants.

Nationwide there have been only two serious accidents involving the shipment of spent fuel. A trucker ran off the road and was killed in 1970, and in 1978, a truck bed buckled under the weight of a cask. No radioactivity was released in the two accidents.

Officials like Montgomery Council member Michael Gudis, who proposed a notification law, admit that their efforts are based on "a fear of the unknown."

"My main concern," Gudis said, "was not to stop the trucks but that we be prepared if, God forbid, we had an accident."

The Department of Energy, which moves its own spent fuel from test reactors and handles some of the military's nuclear waste, also says there has never been an incident in which radioactivity was released. Though there is nearly 10 times as much military nuclear waste, the commercial waste is eight times more radioactive and is expected to far outstrip the radioactivity levels of military waste by the year 2000, according to Goetz Oertel, director of defense waste and programs for the DOE.

Starting in July, under Nuclear Regulatory Commission regulations, shippers moving spent nuclear fuel anywhere and hauling "large quantities" of radioactive material to disposal sites will be required to notify state governors that trucks will be coming through.

In addition, Maryland has embarked on a three-year federally funded study to catalogue the volume of radioactive shipments in the state, and the federal Department of Transportation currently is conducting an $800,000 survey of radioactive materials traffic around the nation.

Whatever improvements states are able to make in tracking nuclear wastes and preparing for the unlikely event of a disaster, fundamental qualms remain. As Fred Millar, of the Environmental Policy Insitute in Washington put it: "Why play high stakes roulette with people? For the government and industry to insist on shipping waste through urban areas is an example of nuclear arrogance."