The federal government is plugging away with a plan to make sure a nuclear power plant catastrophe never befalls the United States, similar to the Fukushima disaster in Japan seven years ago.

The nuclear disaster unfolded after a 9.0 earthquake hit Japan on March 11, 2011. The nuclear power plants on the eastern side of the island nation responded adequately to the quake by shutting down as they are required to do.

But the enormous tidal wave, or tsunami, that resulted from the quake caused the real problems. It resulted in the largest nuclear accident since the 1986 Chernobyl nuclear reactor meltdown in the former Soviet Union.

The tsunami knocked out the back-up power supply to the Daiichi nuclear power plant in the Fukushima prefecture. With the power supply cut, the water pumps couldn't keep the reactors cool, resulting in core meltdowns and a number of explosions. Today, radiation levels have made nearly all the surrounding towns and villages uninhabitable. Herds of radioactive wild boars roam the streets.

The disaster caused a panic across the globe, and some nations such as Germany announced they would stop using nuclear power and switch to coal.

In the U.S., the reaction was more measured, with the Obama White House calling for a review of safeguards at the nation's nuclear plants. The Nuclear Regulatory Commission, the nation's top nuclear safety watchdog, set up a task force to conduct the review and make recommendations to harden U.S. reactors.

Seven years later, all of the nation's 99 reactors comply with NRC regulations established in the wake of the Fukushima disaster, according to the commission.

However, the reactors that are of the same or similar design to the Japanese Daiichi power plant still have some work to do.

The commission ordered all boiling-water reactors with Mark I and Mark II designs to achieve "full compliance" with new venting requirements beginning at the end of June 2018.

The new wet and dry venting requirements would keep the reactor vessels from exploding if a similar scenario occurred in the United States where the reactors could not be cooled.

Hydrogen gas had built up in each of the Japanese plant's six reactors, resulting in significant explosions and making it easier for radioactivity to spread into the environment. Most of the reactors were permanently damaged with no way to restart them.

The new requirements would make sure the U.S. plants can vent off excess heat and gas "so you would not have the catastrophic explosions seen at Fukushima," Scott Burnell, NRC spokesman, told the Washington Examiner.

The agency also required all U.S. power plants to plan for flooding and earthquakes, Burnell said. All U.S. nuclear power plants have completed the required analyses of these threats, and the commission says they are all within acceptable risk limits.

“There are plants for which the updated earthquake hazard does show the need to look at more depth of potential risks posed by that hazard,” Burnell said.

Nevertheless, that does not mean there is a hazard. It just means more updated analyses must be completed to account for the potential threat of an earthquake.

Lawsuits filed against the Japanese utility company that ran the Daiichi plant will be heard in court later this year.

More than 100 U.S. sailors and servicemen who participated in the rescue effort after the tsunami hit Japan are suing the TEPCO electricity company for not warning them about the threat of radiation after they knew of the damage to the power plant.

“The NRC was not a party to that," said Burnell, who said the agency has not been requested by the courts to participate.

In 2011, the commission issued warnings to U.S. citizens in Japan about the risk of radiation, directing all citizens who live within 50 miles of the Daiichi plant to evacuate. Japanese authorities downplayed the seriousness of the radiation and refuted the claims made by then-NRC Chairman Gregory Jaczko.

Senior management at the NRC have visited Fukushima and interacted with their Japanese counterparts since then, Burnell said. The NRC and the Energy Department meet regularly with Japanese officials to discuss what happened.