At times like this, it is critical we do two things. First, we must help. Indeed, the nuclear energy industry is offering extensive technical and humanitarian support.

Second, we must take immediate steps to review the safety of U.S. plants. Responding to growing public concern, the Nuclear Regulatory Commission announced last week that it is planning a thorough review of all safety protocols at all U.S. plants in the next 90 days.

This announcement came soon after a recent NRC inspector general study, which revealed uncertainty among more than a quarter of nuclear plant operators about when to report certain component defects — even those that don’t compromise reactor safety systems.

The NRC has now concluded that all defects must be reported — even those scenarios where the backup system kicked in — to fully protect plant operations and prevent bigger accidents. Many of these problems had, in fact, been reported through a separate regulatory requirement.

The U.S. nuclear energy industry is in the process of verifying each plant’s capability to maintain safety – even with severe adverse events, including loss of significant operational and safety systems due to natural events, like flooding, earthquakes and fires; as well as aircraft impact and explosions.

In addition, plants must now ensure that a total loss of electric power to a nuclear plant does not disable the critical cooling systems.

While the industry is doing this, with the support of the Obama administration and many policymakers, there are others taking a less productive approach. Critics are using this crisis to press for a ban on all future nuclear energy investments and a shutdown of current U.S. nuclear power plants.

That would not only be unwise – it is unrealistic. Nuclear energy provides roughly 20 percent of the electricity that our nation uses. It would take decades — and tens of billions of dollars — to replace that capacity.

Meanwhile, nuclear energy is still one of our country’s cleanest energy options. It provides 70 percent of the country’s carbon-free power every year, and is likely to be counted on even more in the future as Washington strives to rein in harmful emissions. No other energy source can now meet the nation’s future clean energy needs on the same scale.

Moreover, it is always a bad idea to make long-term policy in the middle of a crisis. We cannot guess today how Japan will emerge from this tragedy, or what lessons it will provide.

But this much we do know: The Fukushima plant is in such peril due to two natural disasters – an earthquake and a tsunami. The three reactors in operation when the 9.0 earthquake struck shut down as they were designed to, just as the emergency diesel generators kicked in to begin pumping water around the reactors to cool them down.

The ensuing tsunami, though, disabled the generators, compromising the reactors’ cooling systems, and allowing the core of the reactors to heat up and trigger several explosions.

What this shows is that nuclear safety protocols are multidimensional and complex — and require constant updating. Engineers and safety experts must always revisit the standards by which reactors are protected from such natural disasters, and how they can keep reactors and spent fuel rods cool even without power.

Above all, the containment structures that are the final barrier against the escape of radiation into the atmosphere must be strong enough to withstand significant interior and exterior explosions.

U.S. nuclear energy plants can meet this test. The Nuclear Regulatory Commission, an independent government body, consistently reviews its safety standards and protocols to reflect known and emerging threats.

For example, the NRC requires that all nuclear energy plants can withstand a maximum credible earthquake. And all U.S. power plants — whether they’re in California, which has four plants; or in the Midwest, which has 30 — meet that standard. If the NRC updates and upgrades the requirements, the industry is ready to meet them.

After the 2004 Asian tsunami, the NRC reviewed U.S. nuclear plants to make sure they could withstand such an event. And they judged that they can.

After the 9/11 terror attacks, the NRC required many changes at reactor sites — including stronger security forces and enhanced emergency preparedness and response planning. All U.S. nuclear power plants underwent comprehensive reviews by site-specific teams — that include the NRC, but also the Department of Homeland Security, Department of Energy and the FBI.

The industry also took affirmative steps after that tragedy to make sure engineers could get water to the reactor core in the case of a massive power outage.

These steps do not absolve us of further study and further questioning. We must continue to take the time, and invest the required resources, to further augment our safety standards.

For now, however, the focus must be on averting greater disaster in Japan. After that we will study exactly what went wrong, and why. Then, we can apply those lessons here at home — as we have in the past — so that we can continue to benefit from this critical and clean energy source.

Christine Todd Whitman is the former administrator of the Environmental Protection Agency and former New Jersey governor. She is now co-chairwoman of the Clean and Safe Energy Coalition, funded by the nuclear industry.