Some nuclear power plants could face hazards from climate-driven sea-level rise much greater than the levels they were designed for.
"In 2011, a tsunami sent waves as high as 49 feet crashing over the seawalls surrounding the Fukushima Daiichi Nuclear Power Plant in Japan, causing meltdowns at three of the plant's reactors. After that incident, the United States Nuclear Regulatory Commission (NRC) ordered nuclear facilities in the U.S. to review and update their plans for addressing extreme seismic activity and potential flooding from other events, such as sea level rise and storm surges. Those plans aren't due until March 2015, which means that many plants have yet to even lay out their their potential vulnerabilities, let alone address them.
During the 1970s and 1980s, when many nuclear reactors were first built, most operators estimated that seas would rise at a slow, constant rate. That is, if the oceans rose a fraction of an inch one year, they could be expected to rise by the same amount the next year and every year in the future.
But the seas are now rising much faster than they did in the past, largely due to climate change, which accelerates thermal expansion and melts glaciers and ice caps. Sea levels rose an average of 8 inches between 1880 and 2009, or about 0.06 inches per year. But in the last 20 years, sea levels have risen an average of 0.13 inches per year -- about twice as fast."