While an anxious Europe measured the radioactive fallout yesterday from the Soviet nuclear power plant disaster, supporters and critics of the U.S. nuclear industry waited to measure its political fallout here.

The U.S. commitment to nuclear electric power -- $150 billion so far -- has been bigger than the space program and greater than the cost of the Vietnam war. And its troubles have been on a scale to match.

From the industry's perspective, the role of nuclear power is growing, despite its prominent problems. There are 93 nuclear power plants in commercial operation in the United States, supplying 16 percent of the nation's electrical needs.

Eight more plants are completed and ready to begin operation and another 21 plants are under construction. By 1990, nuclear's share of the nation's electric power is going to be about 20 percent, according to the Edison Electric Institute.

In the decade since the 1973 oil embargo jolted U.S. confidence in oil, nuclear power's contribution to electric power requirements has quadrupled. "That's quite an achievement," said Paul Turner, vice president of the Atomic Industrial Forum.

But after these current plants, there is nothing on nuclear power's drawing board. No orders for plants have been placed since 1978, when the nation's oversupply of electrical-generating capacity became evident, and utilities have canceled orders for 110 plants since 1973.

And since then, the industry's reputation has been repeatedly pounded by a procession of safety controversies, financial crises, regulatory confusion and a sharp drop in electrical power demand.

For many Americans, the nuclear industry is associated with the operating or financial calamities at Three Mile Island, WPPSS in Washington state and Long Island Lighting Co.'s Shoreham plant.

The combination of a stuck valve and operators' errors caused dangerous overheating of a reactor at Three Mile Island south of Harrisburg, Pa., March 28, 1979, in the nation's worst commercial nuclear accident. A comparable financial meltdown struck a group of five nuclear power plant projects planned by the Washington Public Power Supply System (WPPSS, also popularly known as "Whoops"). One was completed, but two were abandoned and two more mothballed, forcing WPPSS to default in 1983 on $2.2 billion in bonds held by 78,000 investors across the country.

Lilco's Shoreham plant triggered a political uproar over safety issues and has not yet received authorization to operate at full power.

"The outcry over nuclear waste, the recurrent problems with nuclear safety, the precarious financial plight of many nuclear utilities all indicate that the industry's problems are coming home to roost," said Rep. Edward J. Markey (D-Mass.), chairman of the House Energy and Commerce subcommittee on energy conservation and power and a longtime critic of the nuclear power industry.

Markey said that the Soviet disaster is likely to stir more public concern about the nuclear industry, even though the construction and technology involved at the Soviet site are said to be dramatically different from U.S. practices.

"Wall Street has long been skeptical, the public has long been skeptical and this accident confirms their fears. The Nuclear Regulatory Commission testified just last year that there was a 50-50 chance of an accident as [severe as], or more severe than, TMI [Three Mile Island] happening in our country in the next 20 years. Clearly both Congress and the public must be on guard and need to be involved in the oversight of the nuclear problem," Markey said.

The unresolved issues include a the dilemma of where to store the increasing amounts of high-level radioactive wastes from power plants. According to the Nuclear Waste Policy Act, the Department of Energy must select three possible long-term storage sites from which a final site will be chosen in time to receive wastes by the late 1990s. Governors from five western and southern states where possible sites could be located told Congress last week to count their states out.

The industry's chief governmental watchdog, the Nuclear Regulatory Commission, has come under steady criticism from within and without the industry since the 1979 TMI accident. Industry critics complain that wavering regulatory policies at NRC have helped swell power plant costs. "You had a regulatory system that basically congealed," the atomic forum's Turner said. Some dissenters in NRC say its commissioners are not bearing down hard enough on safety questions.

Turner contends that the nation will be obliged to turn to nuclear power once again, following other nations that now rely heavily on it, such as France and Canada.

"At current growth rates [in electric power demand] we're not far away from having some kind of crunch . . . At that point, the advantages of nuclear power over coal may tip the balance in nuclear's favor," he said. "I think the options available to us in the future are very limited."

But Loring Mills, a nuclear power expert at the Edison Electric Institute, said, "If a disaster did happen again [here] , it would have a major impact on our ability to commit to nuclear plants in the future."