BEN BOVA: April 17, 2011 ... Fukushima Daiichi ... Nuclear power is still the safest form of energy

The disaster at the Fukushima Daiichi power plant has started people wondering again if nuclear power is safe enough to remain part of our energy picture.

The short answer is, yes. Despite failures such as Fukushima, Three Mile Island and even Chernobyl, nuclear power remains the safest form of energy production we have.

And it can be made even safer.

Recognize that the Fukushima site was struck by twin natural catastrophes of unprecedented magnitude: a Richter 9 earthquake and a tsunami that devastated entire towns and their surrounding countryside. More than 10,000 people have been killed by these terrible calamities.

Still, people are justly worried about the release of radioactive materials from the damaged power plants. Radiation is a subtle killer, capable of causing fatal cancers many years after a person has been exposed.

In reaction to the Fukushima disaster, German chancellor Angela Merkel temporarily shut down seven of that nation's nuclear power plants, and China has suspended approval of any new nuclear plants — despite the fact that the Chinese are now building more new nukes than the rest of the world combined. Or perhaps because of that fact.

Yet a survey by the International Energy Agency, published recently in the British journal New Scientist, clearly shows that nuclear power is much safer than other forms of energy generation.

Coal is by far the deadliest fuel for energy generation. In terms of the number of deaths per 10 billion kilowatt-hours of energy produced, coal mining and production directly kill 2.8 people per 10 billion kWh, while nuclear kills 0.2 in the mining and production of uranium. Indirectly, coal kills 32.7, through diseases related to coal-caused pollution of air and water. Nuclear — including the 9000 eventual cancer deaths from the Chernobyl meltdown in 1986 — kills 1.2.

One of the surprises of the survey is that hydroelectric power kills five times more people directly than nuclear, in construction mishaps. When the 230,000 deaths caused by catastrophic floods due to dam failures in China in 1975 are added in, hydro is the most dangerous energy generation form of all.

The Fukushima reactors were 40 years old. We know how to make better and safer nuclear power plants.

The earthquake damaged the Fukushima plant's power lines and the resulting tsunami flooded the backup diesel generators, cutting off the emergency electrical power needed to run the reactor cooling systems. As a result the reactor cooling water boiled into steam, and the steam was heated to the point where its water separated into hydrogen and oxygen. It was that free hydrogen that exploded and shattered the power plant's roof.

More modern nuclear planets, such as the European Pressurized Reactor designed by the French firm Areva, have much sturdier backup systems, encased in waterproof concrete buildings that can withstand earthquakes. The reactor itself is so heavily shielded it can withstand a direct hit by an airplane.

To avert the possibility of a hydrogen explosion, the EPR type of plant includes equipment that recombines any free hydrogen with oxygen, producing water.

The nuclear reactor is contained inside a double-walled containment vessel that keeps gases from escaping. The inner wall is steel-lined prestressed concrete more than two and a half feet thick; the outer wall is reinforced concrete more than three feet thick.

Westinghouse Electric (which is owned by Toshiba) is building a nuclear plant in China that has a fail-safe feature: a huge water tank on the roof that automatically drenches the reactor if the regular cooling system fails. This can keep the reactor cooled for 72 hours, enough time to allow the crew to deal with the emergency.

No power source is perfectly safe. Coal-fired plants kill thousands per year in lung-related diseases caused by air pollution. Natural gas systems explode with depressing regularity. Nuclear plants, whether damaged by natural causes or human error, can release radiation that kills slowly by causing cancer.

But as long as we need electrical power, we are going to have to live with those risks – and continue to try to make the risks as small as possible.

Ben Bova is the author of 124 books, including "Powersat," a high-tech thriller about building the first solar power satellite. Dr. Bova's website address is

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