Today an earthquake of magnitude 8.9 hit just off the northeast coast of Japan, claiming the lives of hundreds or more and severely disrupting the nation’s airports and transit systems. The earthquake generated a 10-meter tsunami that overwhelmed the cities and land in its path, leaving sheer destruction in its wake. As the world watches Japan deal with the devastation, our hearts go out to everyone touched by this disaster in Japan and across the Pacific. Reports coming from Japan say the quake caused millions of people to evacuate buildings, and the government ordered people near several of the country’s nuclear power plants to leave. Concerns about a radiation leak at the Fukushima Dai-Ichi No. 1 reactor, one of Japan’s 11 nuclear reactors, led to the precautionary evacuation. The biggest concern is that the electricity shortage at the plant is making it difficult for crews to operate the plant’s reactor cooling system quickly.

It is important to remember that the evacuation efforts are cautionary measures rather than indicative of any certain danger posed by the nuclear reactors. Japan’s nuclear power plants, like our own, are built to withstand earthquakes. Plants are engineered to shut down the moment an earthquake hits. Beyond that, each nuclear power plant is fitted with numerous and layered safety mechanisms to ensure the integrity of the facility.

Indeed, even if all of those systems fail, which has not been the case in Japan based on current information, the physics of light water reactors (the type operated in both Japan and the U.S.) make them inherently safe. The same water used to cool the reactor is also necessary to sustain the nuclear reaction. Should the ability to cool the reactor be lost because of an inability to pump coolant to the core, as is the case with the one Japanese reactor, the nuclear reaction will cease. However, it is much too early to even assume that has happened.

Because nuclear power plants are designed and constructed to endure natural disasters and even human error, concern surrounding Japan’s nuclear power plants should not give rise to panic. Chief Cabinet Secretary Yukio Edano made the following assurance at a news conference:

There is no radioactive leakage at this moment outside of the facility … At this moment there is no danger posed to the environment.

In the other well-known incidents at nuclear power plants—Three Mile Island in 1979 and Chernobyl in 1986—equipment malfunctions and inherent design problems, respectively, were to blame. Despite these problems, none of the local population around Three Mile Island’s station suffered significant radiation exposure, and the fatalities from Chernobyl resulted because rescue workers were improperly informed. Since then, technological improvements, training, and disaster preparedness measures have been adopted internationally, leading to increased nuclear power plant safety.

So, it’s too early to tell what happened, but it’s key to remember that safety is taken seriously at nuclear power plants. As the tsunami rolls towards California, normal precautionary steps are likewise being taken to keep operations safe in nuclear plants there, which were all built to withstand big waves, to prevent accidents, and to contain any problems.

Co-authored by Emily Goff.