Democrats ratcheted up pressure on the country’s top nuclear regulators to ensure that U.S. plants can withstand disaster, even as watchdogs charged that the agency has a flawed record of monitoring this country’s aging fleet of reactors.

On Thursday, the Union of Concerned Scientists (UCS) released a study evaluating the NRC’s performance last year as a regulator, saying it has repeatedly found over the years that the agency’s enforcement of safety rules is “not timely, consistent, or effective.”

The UCS cited 14 “near-misses” at domestic plants last year. “In these events, a combination of broken or impaired safety equipment and poor worker training typically led operators of nuclear plants down a pathway toward potentially catastrophic outcomes,” the study said.

The report could provide ammunition to nuclear opponents on Capitol Hill, some of whom are calling for a full stop to U.S. nuclear projects.

Despite these calls, President Obama stuck to his longtime support for the nuclear industry Thursday, calling it “an important part of our energy future.” He also reiterated his call for the NRC to glean lessons from the plant in Japan and apply them to domestic reactors in a full review.

“When we see a crisis like the one in Japan, we have a responsibility to learn from this event and to draw from those lessons to ensure the safety and security of our people,” Obama said. “That’s why I’ve asked the Nuclear Regulatory Commission to do a comprehensive review of the safety of our domestic nuclear plants in light of the natural disaster that unfolded in Japan.”

Obama does not have the authority to direct the NRC because it is an independent agency.

“The NRC is an independent agency, and they have the authority to determine how best to conduct an expert review — as [the NRC chairman] made clear in testimony yesterday,” said White House spokesman Clark Stevens.

The head of the NRC, Gregory Jaczko, said the agency monitors the safety of plants on a “minute-by-minute” basis. He cautioned that information from the plant in Japan was still sketchy but said that the agency would apply any lessons learned from the crisis unfolding at the Fukushima Daiichi complex.

“We don’t really know exactly what the most relevant information is right now from Japan,” said Jaczko during a briefing. “So we want to get that information, and we want to do a systematic and a methodical look at what changes we may need to make to those types of plants or possibly any other types of plants in the country.”

Democratic lawmakers called on the NRC on Thursday to immediately review how plants would fare in a catastrophe.

“Safety is always our number one priority, and therefore it is vital that the NRC immediately evaluate the risks posed to nuclear reactors in the United States,” wrote Sen. Barbara Boxer (D-Calif.), chairman of the environment and public works committee, and Sen. Thomas R. Carper (D-Del.) in a letter to the agency. They also requested information about the readiness of U.S. reactors.

Meanwhile, the UCS report isolated three instances in which the agency performed laudably and three in which it made dangerous errors.

The report praised an instance at the Browns Ferry plant in Alabama where inspectors asked tough questions about an oil leak that led to the recall of a product that was being used at several U.S. reactors.

But the UCS also pinpointed an incident at the Peach Bottom plant in Pennsylvania where workers dodged regulations that might have led to it being shut down; the report alleges that NRC inspectors knew about the problem but didn’t fix it.

The NRC did not respond to a call for comment on the report.

Opponents of nuclear power are increasing their pressure on the president to act as the situation in Japan grows more dire. Obama has been an advocate for nuclear energy. This year, he proposed increasing the funds allocated to the government’s loan guarantee program for the nuclear industry to $54.5 billion.

“As a first step, President Obama should immediately halt his push for expansion of this dangerous industry,” said Erich Pica, president of Friends of the Earth U.S. “Reactors cannot be built without billions in taxpayer-funded bailouts because even Wall Street sees the risks as too high.”

Staff writer Perry Bacon Jr. contributed to this report.