December 21, 2024

A Safer Nuclear Crypt

Yet this catch was far more menacing: 57,000 pounds of spent nuclear fuel at the LaSalle nuclear plant here, stored for decades in a pool and, if unshielded, powerful enough to deliver a lethal dose of radiation within seconds.

The fuel had just been moved into a capsule the size of a small silo, called a dry cask. Welded shut after it came out of the water, the cask was pumped full of inert gas, placed in an outer cask and moved outdoors to a concrete pad where it will sit until a disposal site is found. Spent fuel must be isolated from the environment for hundreds of thousands of years before it loses its potency.

The nuclear calamity at Japan’s Fukushima Daiichi plant has refocused attention on the vulnerability of spent fuel pools at the 104 operating American nuclear plants.

The pools are generally far more packed than the damaged ones at Fukushima. Some scientists argue that the crowding raises the risk of a fire and makes the pools a tempting target for terrorists.

Several members of Congress are calling for the fuel to be moved from the pools into dry casks at a faster clip, noting that the casks are thought to be capable of withstanding an earthquake or a plane crash, they have no moving parts and they require no electricity.

“We should not wait for an American meltdown to beef up American nuclear safety measures,” Representative Edward J. Markey of Massachusetts, who advocates greater reliance on casks, said after the accident in March in Japan. “We must heed the lessons to be learned from the nuclear meltdown in Japan and ensure nuclear safety here.”

But transferring the fuel to dry casks involves risks of its own, some industry experts say. “It’s a very complex discussion,” said Neil Wilmshurst, a nuclear power expert and a vice president of the Electric Power Research Institute, a nonprofit utility consortium. “Every time you move spent fuel, there’s always a risk of human error. How much of this do you want to do if you don’t need to do it?”

The discussion is unfolding amid a far broader and more divisive debate over nuclear waste disposal. A half-century after the American nuclear industry was born, the nation still lacks a dedicated repository for such waste because of maneuvering driven by not-in-my-backyard politics.

In 1987 Congress designated Yucca Mountain, a desolate volcanic ridge in the Nevada desert, as a national disposal site, ruling out sites in Texas and Washington State. But the political landscape shifted, and the Obama administration canceled the project in 2009 under pressure from Senator Harry Reid of Nevada, leader of the Senate’s Democratic majority.

Then came the earthquake and tsunami at Fukushima, which cut off power to four reactors and caused three cores to melt. The melting fuel in the reactors released hydrogen gas that then exploded, throwing debris into the fuel pools, destroying a barrier that had prevented the release of radioactive materials to the outdoors and leaving the pools exposed to the rain.

Suddenly, the Nuclear Regulatory Commission was under pressure to explain whether crowded American pools faced parallel risks.

Gregory B. Jaczko, chairman of the commission and a former aide to Senator Reid, contends that both fuel pools and dry cask storage are relatively safe, with any differences being fractional. “It’s like the difference between buying one ticket in the Powerball lottery and 10 tickets,” he said in an interview, referring to the odds that something will go wrong.

But Robert Alvarez, a former senior adviser to the secretary of energy and expert on nuclear power, points out that unlike the fuel pools, dry casks survived the tsunami at Fukushima unscathed. “They don’t get much attention because they didn’t fail,” he said.

In addition to the United States and Japan, plenty of other countries make extensive use of casks, usually storing them at reactor sites. Germany has gone a step further, placing them in installations designed to protect the casks from airplane crashes.

After Japan’s disaster, the Tennessee Valley Authority said it would study the possibility of moving more fuel to casks, but so far other American operators have not followed suit. Moving all of the nation’s fuel once it has cooled in the pools for at least five years could cost $7 billion, Mr. Alvarez said.

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Risk From Spent Nuclear Reactor Fuel Is Greater in U.S. Than in Japan, Study Says

The report, from the Institute for Policy Studies, recommends that the United States transfer most of the nation’s spent nuclear fuel from pools filled with cooling water to dry sealed steel casks to limit the risk of an accident resulting from an earthquake, terrorism or other event.

“The largest concentrations of radioactivity on the planet will remain in storage at U.S. reactor sites for the indefinite future,” the report’s author, Robert Alvarez, a senior scholar at the institute, wrote. “In protecting America from nuclear catastrophe, safely securing the spent fuel by eliminating highly radioactive, crowded pools should be a public safety priority of the highest degree.”

At one plant that is a near twin of the Fukushima units, Vermont Yankee on the border of Massachusetts and Vermont, the spent fuel in a pool at the solitary reactor exceeds the inventory in all four of the damaged Fukushima reactors combined, the report notes.

After a March 11 earthquake and tsunami hit the Japanese plant, United States officials urged Americans to stay at least 50 miles away, citing the possibility of a major release of radioactive materials from the pool at Unit 4. The warning has reinvigorated debate about the safety of the far more crowded fuel pools at American nuclear plants.

Adding to concern, President Obama canceled a plan for a repository at Yucca Mountain in the Nevada desert last year, making it likely that the spent fuel will accumulate at the nation’s reactors for years to come.

The Nuclear Regulatory Commission maintains that both pool and cask storage are safe, although it plans to re-examine the pool issue in light of events at Fukushima.

Nearly all American reactors, especially the older ones, have far more spent fuel on hand than was anticipated when they were designed, Mr. Alvarez, a former senior adviser at the Department of Energy, wrote.

In general, the plants with the largest inventories are the older ones with multiple reactors. By Mr. Alvarez’s calculation, the largest amount of spent fuel is at the Millstone Point plant in Waterford, Conn., where two reactors are still operating and one is retired. The second-biggest is at the Palo Verde complex in Wintersburg, Ariz., the largest nuclear power plant in the United States, with three reactors.

Companies that run reactors are generally reluctant to say how much spent fuel they have on hand, citing security concerns. But Mr. Alvarez, drawing from the environmental impact statement for the proposed repository at Yucca Mountain, estimated the amount of radioactive material at all of the nation’s reactors.

In the 1960s, when most of the 104 reactors operating today were conceived, reactor manufacturers assumed that the fuel would be trucked away to factories for reprocessing to recover uranium. But reprocessing proved a commercial flop and was banned in the United States in the 1970s out of concerns that the plutonium could find its way into weapons worldwide.

Today roughly 75 percent of the nation’s spent nuclear fuel is stored in pools, the report said, citing data from the Nuclear Energy Institute. About 25 percent is stored in dry casks, or sealed steel containers within a concrete enclosure. The fuel is cooled by the natural flow of air around the steel container.

But spent fuel is transferred to dry casks only when reactor pools are nearly completely full. The report recommends instead that all spent nuclear fuel older than five years be stored in the casks. It estimated that the effort would take 10 years and cost $3.5 billion to $7 billion.

“With a price tag of as much as $7 billion, the cost of fixing America’s nuclear vulnerabilities may sound high, specially given the heated budget debate occurring in Washington,” Mr. Alvarez wrote. “But the price of doing too little is incalculable.”

The casks are not viewed as a replacement for a permanent disposal site, but as an interim solution that would last for decades.

The security of spent fuel pools also drew new attention after the attacks of Sept. 11, 2001, partly because one of the planes hijacked by terrorists flew down the Hudson River, over the Indian Point nuclear complex in Westchester County, before crashing into the World Trade Center in Manhattan.

Indian Point has pressurized water reactors with containment domes, but its spent fuel pools are outside the domes. The pools themselves are designed to withstand earthquakes and other challenges, but the surrounding buildings are not nearly as strong as those that house the reactors.

In a 2005 study ordered by Congress, the National Academy of Sciences also concluded that the pools were a credible target for terrorist attack and that consideration should be given to moving some fuel to dry casks.

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