The jarring Three Mile Island accident 100 miles from here has left most Washington area residents persuaded that there will be a much worse nuclear disaster in the days or years ahead. But it has failed to make them reject nuclear power as an answer to the nation's energy needs.

These are among the chief findings of a Washington Post telephone poll on nuclear power and energy problems conducted Tuesday through Friday.

Large majorities of the 934 people interviewed feel that Metropolitan Edison Co., the utlity that ran the power plant at Three Mile Island in Pennsylvania, could have prevented the accident, that it did not know what to do once the accident occurred, that it understated the problem and that it was not candid with the public.

The federal government, while considered much more candid and able than Metropolitan Edison, still was seen as falling short in its handling of the incident. Only 43 percent of those interviewed said they felt the government knew what to do once the accident occurred, while 45 percent felt the government did not know what to do.

"I just feel terrible for the families there who have to be exposed to that and have to leave their homes," a young District of Columbia woman said. "This is something that can happen to all of us at any time."

That woman, who said she was an opponent of the use of nuclear power both before and after the Pennsylvania accident, was one of 52 percent of those interviewed who feel that a worse nuclear power plant accident is likely in the future. Forty-one percent of those interviewed said they felt such a disaster would be unlikely; 7 percent had no opinion.

In response to question after question, the bulk of Washington area residents show themselves to dread nuclear power but to feel stuck with it. That was how they say they felt before the near meltdown and how they feel now. Hardly any of those interviewed say their opinions on nuclear energy have changed as a result of the accident.

That they take the events of the past 10 days seriously is beyond question. One-third of those interviewed said they thought the Pennsylvania accident presented a real danger to people living in the Washington area; only half said they were as likely now as before the accident to visit the beautiful Pennsylvania Dutch country or other places near Three Mile Island.

Sixty-six percent called the incident very serious and 25 percent termed it somewhat serious. Only one person in a hundred said it was not serious at all.

Asked whether they supported, opposed or were neutral toward nuclear power before the accident, 38 percent said they had been supporters, 18 percent described themselves as opponents in the past, and 44 percent said they had previously been neutral or had no opinion.

Asked whether they supported, opposed or were neutral toward nuclear power after the accident, the same number - 38 percent - said they were supporters. Twenty-eight percent said they were opponents and 34 percent said they were neutral or had no opinion.

The accident, then, appears to have shifted the opinions of some 10 percent of the population, pushing them from undecided or neutral into a position of opposition to the development of nuclear power plants.

It has hardened opinions as well. "I was opposed before, but I'm more opposed now," a Bethesda woman said. "Not enough people are talking about long range goals with regard to energy."

An explanation for the lack of a massive shift against nuclear power may be quite simple: Washington area residents appear more willing to face the unknown danger of a catastrophe elsewhere than go without power in their own homes or pay huge electric bills.

The Post poll set four energy policy positions before the public, asking those interviewed to state which one they tended to approve most.

The first policy would have the government shut all nuclear plants and go all-out to develop other sources of energy, at the risk of power outages and much higher electric bills. Seven percent said they supported such a policy.

The second advocated tougher inspection of existing nuclear plants and government refusal to allow the building of new nuclear plants. Twenty-eight percent chose that position.

The third called for the government to "continue to develop nuclear power plants, but with more stringent safety and inspection rules." Fifty-eight percent, by far the largest group, chose that option.

The fourth policy would have the government continue to promote nuclear power under existing safety and inspection rules. Only 5 percent chose it.

Go nuclear, but with as much care as possible, was the clear majority theme, often articulated in volunteered comments from those interviewed.

"I was really surprised how close to a meltdown the thing came," said a 27-year-old Montgomery County man. "I knew they would prevent a meltdown, but it came really close. Apparently we need more regulations, although there are a lot now."

The sense of having to live on the edge was voiced by a 22-year-old Herndon woman who feels there is no energy shortage and that there will not be any but that the United States is caught in a bind nevertheless. "This is something I expected to happen," she said of the accident, "but I believe nuclear power plants are imperative to the future."

One other factor may help account for the failure of opponents of nuclear power to develop greater support here following the Three Mile Island accident - the absense of nuclear facilities in the immediate area, and the probable conviction on the part of many that none will be built.

In recent years, antinuclear groups have been successful in blocking the construction of many nuclear facilities. The people interviewed by The Post were asked how they would feel about having a nuclear plant within a five-mile radius of where they live.

Only 33 percent said they would not be against one. Sixty-one percent said they would be against one, and 6 percent said they were uncertain.

With sentiment like that, the likelihood of a nuclear facility that could cause local catastrophe may not be threatening to most Washingtonians.

Ordinarily, public opinion is sharply swaved by especially jolting events. Sentiment leans heavily toward capital punishment after horrid highly publicized murders. But if reaction from Washington area residents is typical, then the events in Pennsylvania may have resulted in only a slight national shift in attitudes toward the need for nuclear power.

In 1976, the Gallup Poll asked Americans how important they thought it was to have more nuclear power plants to meet the future power needs of the nation. Thirty-four percent nationwide said it was very important and 37 percent said it was somewhat important.

In The Post poll last week, the same question was asked. Twenty-nine percent said nuclear power plants were very important, and 36 percent said they were somewhat important - a decline from 71 percent to 65 percent.

In his televised energy message Thursday night, President Carter asked peeople to pay attention to what he had to say. They probably did, for they certainly have been paying attention to the events in Pennsylvania. Of those polled by The Post, 97 percent said they had heard of the accident there, and 85 percent said they had been following it very closely or somewhat closely. CAPTION: Graph, Results from poll of 934 Washington area residents, taken Tuesday through Friday, The Washington Post