A slim majority of Americans see nuclear power plants as a safe energy source, but nearly two-thirds reject the idea of building new reactors in the United States at this time, according to a new Washington Post-ABC News poll.

The 53 percent who approve of nuclear power are a mirror image of the 53 percent who said such power was unsafe in the wake of the 1986 meltdown at the Chernobyl plant in Ukraine. But while there is majority support, more than four in 10 say they’re less confident in U.S. reactor safety after the troubles at the Fukushima Daiichi nuclear plant in Japan.

More — just over half — say the nuclear crisis in Japan has not led to a fundamental loss of confidence in U.S. plants. But there is less support than there was three years ago for new plants here.

By a nearly 2 to 1 margin, more people oppose building new plants (64 percent against, 33 percent in favor). That’s a shift from July 2008, when new plants were opposed by a 53 to 44 percent margin. Since 2008, the percentage who “strongly oppose” new plants has more than doubled, from 23 to 47 percent. The poll shows the highest level of strong opposition in a decade.

Strong opposition to plants spiked to 59 percent when respondents were asked whether they’d support a new nuclear facility within 50 miles of their home.

The perceived lessons from Japan make a difference among those who say they feel less confident in U.S. nuclear power plants. Fully 67 percent strongly oppose building new plants anywhere in the country, rising to 84 percent against a facility nearby.

Support for nuclear plant construction in the United States has not been particularly popular over the past 30 years although basic support levels have fluctuated. In the late 1970s, about half of all Americans favored building nuclear plants. Public views soured briefly after the March 1979 near-disaster at the Three Mile Island plant in Pennsylvania.

Support fell sharply in the 1980s, dropping to 19 percent in spring 1986, after Chernobyl. The 25th anniversary of the Chernobyl accident is Tuesday.

Since then, support has rebounded, climbing as high as 44 percent in 2008 before fading to 33 percent in the new poll.

The changes over the past three years are largely partisan. In 2008, 60 percent of Republicans favored building more plants. GOP support has dropped to 37 percent today. Support among Democrats and independents is also down, but not as sharply.

There continues to be a bright dividing line on nuclear power issues between men and women. By a 20-point margin, more women than men oppose building nuclear plants. By 14 points, more women than men say plants are unsafe, and, by 18 points, more women than men say they are less confident in nuclear power because of the incident in Japan.

The telephone poll was conducted April 14-17 among a random national sample of 1,001 adults interviewed on conventional or cellular telephones. The margin of sampling error for the full poll is plus or minus 3.5 percentage points.