Consumer advocate Ralph Nader opened a nationwide series of teach-ins and seminars opposing nuclear power plants yesterday by calling for a grassroots "blizzard of petitions, surveys and questionnaires" to Congress on the issue.

He told about 400 students and anti-nuclear group representatives at American University that "scientific charlatans" have been misleading the public about the safety of nuclear technology. Worries expressed by individual engineers and scientists in their particular fields "add up to a massive, comprehensive indictment of the (nuclear) industry by the industry itself," he added.

Nader was applauded when he told the group that President Carter has become isolated from antinuclear thinking and from advocates of increased reliance on solar energy, and that most members of Congress refuse to take a stand on these issues.

"The question of energy is one of choices, not of supply, and of who is going to run the society," Nader said. "The levers here (in Washington) can be pulled by relatively modest numbers of citizens operating in each (congressional) district . . . 50,000 or 100,000 people would mean a dramatic difference in Congress."

Nader's talk was the first in a daylong seminar, one of 50 or more being planned for the coming months by an ad hoc Philadelphia group called Mobilization for Survival, according to Peter Bradford of the Citizens' Energy Forum of McLean which set up the gathering . Other seminars were held yesterday in New York and California, he said.

Participants at American University were invited to sign generalized petitions circulated by Nader's Critical Mass organization that would be used "again and again" in lobbying congressmen, Nader said. The petition endorsed "legislation to foster wide use of solar energy and to phase out nuclear power." He said he already had collected 540,000 signatures nation-wide.

He told the gathering he was pushing a proposal to require all utility companies to include with their monthly bills a slop of paper inviting customers to contribute to the formation of a citizens' energy consumer committee. The group would then watch over consumers' rights in rate disputes and when state legislation on energy matters is being debated he said.

Nader said the proposal had passed one house in the Maryland and New York state legislatures, failed in Iowa and was on its way to passage in California. "It would be an absolutely unassailable force for change," he said.

Nader also proposed creation of an "environmental bankruptcy" law that would allow judges to declare a firm's assets frozen in order to pay for repair of its damage to the environment. "At the moment the criminal tells the society how much he can pay to clean up . . . this way we could expropriate the assets of Getty Oil CO. to take care of West Valley, N.Y.," where Getty and New York state were part of an unsuccessful nuclearn reprocess in operation.

Nader said the nuclear industry as a whole is in growing financial trouble as capital, operating and other costs skyrocket while older plants are wearing out. Any calculation of the price of nuclear power must include the costs of waste treatment and of decommissioning radioactive power plants as they wear out, he said, costs that the conventional accounting of utilities never considers.

Others speakers at the gathering included Dr. Judith Johnsrud, coordinator of two antinuclear group; Dr. Ernest Sternglass, a Pittsburgh radiologist who is vocal on health dangers of nuclear plans; Dr. Helen Caldicott, on Australian antinuclear activist and pediatrician; and June Allen, head of the North Anna Environmental Coalition that opposes nuclear plants under way on the North Anna River in Virginia.