Editor's note: Frances Beinecke is president of the Natural Resources Defense Council, an environmental advocacy organization with 1.3 million members and activists nationwide. For a different view, see Why nuclear power is a necessity.
(CNN) -- Our thoughts and prayers go out to the people of Japan as they cope with the fallout of a catastrophic earthquake, a horrific tsunami and the worst nuclear crisis since Chernobyl.
The nuclear situation is complicated, the risks are grave and growing and events are moving too quickly for final judgments or conclusions.
Five days into this crisis, though, several things are clear.
First, nuclear technology carries with it catastrophic risks. Guarding against these risks is expensive, but imperative. We need to do a better job. The tragedy unfolding at the Daiichi nuclear power plant in Fukushima is demonstrating why.
Elevated levels of radioactivity have been released already from Daiichi, which has had explosions at three reactors and a fire at a fourth. As of this writing, 750 workers have been evacuated from the plant, leaving an emergency staff of 50 that is constrained because radiation levels are so high.
The nuclear reactor cores in units 1, 2 and 3 have all suffered a partial melting, essentially what happened to just one reactor at Three Mile Island in 1979.
In all three reactors, the level of coolant water fell so low it left fuel rods partly uncovered, causing them to overheat and then produce hydrogen, which later exploded.
Workers are struggling heroically to keep enough seawater running through the reactors to prevent a full meltdown, an especially serious danger at reactor No. 2. If that happens, the result could be an uncontrolled release of high levels of radioactive gases that could put people at risk both near the site and far downwind.
As we learn hard lessons from the crisis in Japan, we must move, in this country, to a complete review and reassessment of the nuclear safeguards we rely on to protect us from the risk of catastrophe.
We need, for one thing, to improve our contingency plans for station blackouts.
Nuclear reactors, and the spent fuel they produce, are cooled by water circulated by electric pumps. The fundamental problem at the Daiichi plant is that the facility lost electric power, its pumps went down and backup pumping systems failed.
That could happen to U.S. plants, due, for example, to winter storms, hurricanes, terrorist attacks and even, in some regions, earthquakes.
In Japan, the need for cooling water quickly outstripped the limited backup that batteries provided. Are we in any better shape here in our country? Nuclear Regulatory Commission research found that some plants only had a four-hour battery backup. How can we strengthen our ability to respond to a station blackout? In light of this crisis, those capabilities demand urgent review.
What about spent fuel? Currently, spent fuel from nuclear reactors goes into large pools of water for cooling. Once cooled, or once these pools are too full to take any more fuel, the fuel is entombed in concrete and stored -- again, on site -- in solid casks.
Spent fuel pools are a liability. Right now, we estimate there are 60,000 tons of spent nuclear fuel stored beside U.S. nuclear reactors. If levels of water in a spent fuel pool drop, exposed fuel rods can heat up and temperatures can become high enough to ignite the zirconium cladding that encases the fuel rods.
Zirconium burns at furiously high temperatures that can be difficult, if not impossible, to extinguish. We need, in this country, to look into accelerating the rate at which spent fuel pools are emptied and spent fuel rods are entombed in cement casks.
That still leaves us with the problem of long-term disposal of spent fuel in this country. We haven't yet solved that problem, so spent fuel remains on site at nuclear power plants around the country.
It's not only a liability in terms of safety; in the hands of terrorists, spent fuel could pose a serious security threat.
Nuclear power in this country needs to be safe. As we're seeing in Fukushima, though, this technology carries with it catastrophic risk that must be minimized, no matter the cost.
Apart from the dangers of catastrophic disaster, nuclear power also exacts huge environmental costs. From the mining and milling of uranium to reactor operations and all the way through to spent fuel disposal, this technology harms or threatens fresh water supplies and land on a massive scale. That toll is not fully reflected in the price we pay for nuclear fuel.
Finally, nuclear power must be cost effective. Instead, it depends on taxpayer subsidies in two ways.
First, the government guarantees loans for nuclear power plants -- taxpayers stepping in to assume risk where Wall Street fears to tread. Second, the federal government insures power plants against the risk of catastrophic disaster; the private sector won't underwrite risk that high.
After more than 50 years, nuclear power is no longer an experimental technology. It should not be subsidized by taxpayers.
And yet, the administration has asked Congress to provide an additional $36 billion in loan guarantees to help finance the next generation of nuclear power plants in this country. Why? The administration has pledged $8.3 billion in loan guarantees to the Southern Co., which is seeking Nuclear Regulatory Commission approval to add two new reactors to its Plant Vogtle nuclear facility in Georgia.
After more than 50 years, the question must be asked: When will the nuclear power industry finally demonstrate that it can provide safe and reliable power to consumers without public subsidies?
That is what the American public has the right to expect from the nuclear power industry.
The opinions expressed in this commentary are solely those of Frances Beinecke.