When the first U.S. nuclear power plants went on line more than half a century ago, utilities built small cooling pools next to the reactors to store their radioactive waste, like the ones at Japan's Fukushima plant that overheated and probably leaked radiation into the environment.
FOR THE RECORD:
U.S. nuclear waste: A March 23 Section A article about U.S. nuclear waste management said a 2005 National Research Council study recommended that the Nuclear Regulatory Commission force utilities to partially unload pools of spent fuel rods at their nuclear power plants and move their oldest waste into dry casks, which are considered much safer. The council did not make a formal recommendation but advised the NRC to determine whether such a change would be prudent. —
The utilities erroneously thought the pools would be for temporary storage only: The federal government had promised it would find a safe place to bury the used-up fuel rods, which remain radioactive for thousands of years.
It has yet to make good on that commitment.
Technical miscalculations, multibillion-dollar lawsuits and political stalemates over nuclear waste have kept the decaying radioactive material stationary for decades, accumulating across the country ever since the Eisenhower administration.
Now the nuclear disaster in Japan, in which at least one spent fuel pool seems to be damaged and leaking and may have caught fire, has thrown U.S. decisions about its own waste into sharp focus, exposing what many scientists call a serious compromise in safety.
The risks taken at the Fukushima Daiichi plant were actually less than those in the U.S., nuclear scientists say, because utilities here have been forced to pack more fuel rods into pools than they were designed to hold, increasing the density and therefore the chance that they could catch fire if they were to lose the water that cools them.
"The pools in Fukushima were not filled to capacity, and the accident could have been a lot worse if they were filled as densely as ours are," said Edwin Lyman, a physicist with the Union of Concerned Scientists.
The Nuclear Regulatory Commission, which oversees commercial reactors in the U.S., this week launched a 90-day review of reactor safety and plans a more comprehensive long-term examination of its regulations. The pools, considered by outside experts the most important nuclear energy safety issue, almost certainly will be part of that.
The decision to massively overfill the pools has been pushed by the growing inventory of nuclear waste and a lack of a place to send it.
The U.S. now has about 65,000 tons of the material spread from the East Coast to the West Coast and from the northern woods to Mexican-border states. With growing anxiety, experts have debated the waste's short-term vulnerability to accident or terrorist attack and its long-term potential to leak into the environment through political neglect.
"U.S. operators are going to have to go back and rethink their decisions because of what happened in Japan," said Kevin Crowley, director of the board on radioactive waste management at the National Research Council, which advises the federal government.
Crowley led a 2005 study that reported that overloading the U.S. pools put them at risk if they were to lose cooling. The study considered a terrorist attack that could puncture a hole in the pools, as well as human errors or natural events.
Without cooling, the spent fuel can get so hot that zirconium tubing that holds uranium pellets begins to oxidize and potentially melt radioactive isotopes, sending them into the atmosphere.
The report recommended that the Nuclear Regulatory Commission force utilities to partially unload their pools and move their oldest waste into dry casks, which are widely considered much safer.
Utilities at plants all over the country have already loaded hundreds of dry casks with nuclear waste. But they could be loading much more and reducing the amount stored in pools, the study authors said.
And though utilities did rearrange fuel rods to checkerboard newer and older fuel, nuclear experts said the commission did not require plant operators to reduce the density of the fuel.
The industry maintains that there is nothing to worry about.
"We believe the pools are safe," said Rod McCullum, director of used-fuel programs at the Nuclear Energy Institute, the industry's primary trade group. "It is not necessary to move the fuel. You don't gain a considerable amount of safety by moving to dry casks."
McCullum said that the U.S. pools have multiple layers of safety, including redundant cooling systems and leakage monitoring, though he declined to say that U.S. pools are safer than those at Fukushima.
He said the industry would review its procedures and plans to ensure that they are adequate. And he said he believed the Japanese were handling their accident well.
"The radiation levels, while not acceptable, are manageable," he said.