Nearly all of the
nuclear power plants in the U.S. have already run out of storage space, because these pools were not designed to be long-term containers and enough room needs to be preserved in case of a crisis such as a meltdown. In the absence of a long-term solution (such as burying the waste deep inside Yucca Mountain), the nuclear industry has turned to so-called
dry cask storage.
This involves immersing the radioactive used rods in helium or some other inert gas and slotting them into a steel container that is further encased in a concrete cask—at a cost of roughly $1 million per cask. The encased rods still manage to emit roughly one millirem of radiation per hour and heat the outside of the 100-plus ton concrete casing to as much as 90 degrees Fahrenheit (32 degrees Celsius).
“These are placed in rows on a concrete pad for stability. They’re essentially out in the air,” says NRC’s McIntyre. “Generally, they are putting them within the controlled area of the reactor site so they are protected under the physical security of the plant.”
Some 9,000 metric tons of spent fuel rods are already stored encased in some 900 such casks—the bulk of them stored vertically in concrete casks but some placed horizontally into concrete bunkers. Their makers—companies like New Jersey-based
Holtec International and AREVA’s
Transnuclear, Inc.—and the NRC maintain that such dry cask storage will last for at least a century, if not longer. “They’ve had an excellent safety record over the past 22 years they’ve been in use,” McIntyre says. “All signs are that they are safe and secure.”
But some environmentalists and other nuclear power critics contend that such dry casks present a tempting target for terrorists and a disaster for the environment if ever breached. In fact, the San Luis Obispo, Calif., chapter of
Mothers for Peace has successfully sued the NRC and power utility Pacific Gas & Electric Co.—owners of the Diablo Canyon power plant—for failing to take into account the impact of a potential terrorist strike when assessing the environmental risks of a new, proposed on-site dry cask storage area.