Staff file photo by Doug Strickland Unit 2 senior manager of operations Tom Wallace walks inside the Unit 2 cooling tower of TVA's Watts Bar nuclear in 2015. TVA met stricter flood and disaster rules for all three of its nuclear plants as part of its effort to get the new Unit 2 of Watts Bar licensed by the Nuclear Regulatory Commission.

In this time of climate change preparation — such as we have it under the Trump chaos reign — nuclear power is a two-edged sword.

Why? Because nuclear power is carbon-free power, meaning we can't give it up. The clock is ticking on the dozen years that climate scientists say we have to stop filling our atmosphere with too much stuff or suffer the worst of the expected eventual affects of global warming.

"Today, 98 nuclear reactors provide about 20 percent of our electricity in the United States — and 60 percent of all carbon-free electricity in the United States," according to Sen. Lamar Alexander, R-Tenn., and a fervent advocate of nuclear power.

On the other hand, nuclear power remains fragile, unreliable and frightening, and this is hardly the time for the Trump administration's Nuclear Regulatory Commission to back away from every possible safeguard we can ask of our nuclear industry.

Alexander, who argues for more nuclear plants, would disagree with that "fragile, unreliable and frightening" statement, but you need look only to Fukushima, Japan, where tens of thousands of people can't go home after a March 2011 9.0 earthquake and subsequent tsunami led to three reactor meltdowns.

For that matter, look to our own April 2011 tornado outbreak — 492 tornadoes in the Southeast in the space of about three days. The tornadoes left nearly 360 people in the Southeast dead, and they also took down all three of Browns Ferry Nuclear Plant's reactors.

Here in the Tennessee Valley, we avoided the Fukushima meltdowns, but it wasn't as easy as the Tennessee Valley Authority first wanted us to believe.

The tornadoes turned 353 of TVA's monster power towers in the Alabama and Mississippi grid into twisted hulks of junk, downing 108 power transmission lines. With no place for the 3,400 megawatts of power generated by Browns Ferry to go, the plant tripped and went into automatic shutdown. With no electricity, the plant's three reactors and three spent fuel pools were cooled for at least five days with only diesel generator power to pull in water from the Tennessee River.

But two of the eight diesel generators malfunctioned for about 40 and 50 minutes. That's not all.

Despite TVA statements then that everything functioned as it should, documents the utility was later required to submit to the NRC showed reactor operators became distracted while manually operating cooling water flow, and water began boiling off of one reactor faster than cooling water could replace it.

Additionally, a valve failed, a diesel-driven fire pump failed, the diesel-driven generator for the security station failed, the warning sirens were lost, power to the chemical lab was lost and at least one of the emergency diesel generators keeping cool water flowing to Unit 1 shut down because of voltage fluctuations caused by a fluid leak after a brass fitting broke.

So much for "the equipment worked as designed." With those systems failures, it seems little wonder that reactor operators became distracted. The water in the reactor boiled low enough to trigger another shutdown alarm in the control room, said then-TVA spokesman Ray Golden, but boiling water still covered the reactor fuel.

After the tornadoes, TVA spent nearly $200 million to replace the destroyed power lines and another $95 million to buy replacement power, as Browns Ferry was unable to resume full power generation for weeks.

At that point, Browns Ferry was already under heightened scrutiny by the NRC: A cooling water valve failed to operate during a routine manual shutdown the previous fall, and it then came to light that the valve may not have functioned for 18 months before the tornado outbreak. By July 2013, TVA had been cited by NRC nine times in three years for incidents at Browns Ferry alone. Watts Bar and Sequoyah had more than their fair share of citations, as well, and at one point, all three of the plants were under one or another of NRC's warning ratings, including Browns Ferry's "red" finding — NRC's most serious violation short of ordering a plant to be shut down.

Still, the fact is, we have to have these nuclear plants if we're to save ourselves and our planet from the very worst of global warming. Yes, we need solar and wind power, too — but that's another day's subject.

Today, what we must make clear to our government, our political candidates, the nuclear industry and the NRC is that this is not the time for either the NRC or the industry to back off safety rules or give up looking for safer ways to make power with nuclear energy.

Yet that seems to be exactly what NRC's new Trump-appointed majority commission has done.

In January, three commissioners appointed by Trump ruled that nuclear plants wouldn't have to update or redesign equipment to deal with climate change and its higher levels of expected flooding. Two commissioners disagreed. But with the majority vote, the commission even eliminated a requirement that plants run Flex drills. Flex — the short name for Flexible Mitigation Capability — is an industry preferred system of storing emergency generators, pumps, and other equipment in on-site concrete bunkers. (All three of TVA's nuclear plants already are Flex-certified and already meet the tougher "probable maximum flood" values not specifically included in NRC's final post-Fukushima rules.)

NRC spokesman Scott Burnell on Monday said NRC will continue to look at nuclear plant licensing in a case-by-case way, and "available evidence suggests sea level rise or flooding events will occur slowly enough for the NRC and U.S. nuclear power plants to take appropriate actions to maintain public health and safety."

Sorry, but it sure sounds like we studied the lessons of both Fukushima and climate change, then fed our homework to the dogs.