Can Extreme Engineering Save Nuclear Plants from Disasters?
Hospitals and oil rigs use the equivalent of giant shock absorbers to ride out earthquakes and keep on working after the tremors have stopped. But just six nuclear reactors in the world have such advanced protection, and none are in Japan.
Japan's nuclear power plants mostly survived a deadly 9.0 magnitude earthquake intact. Yet several are in a near-meltdown crisis because tsunami waves knocked out the power for reactor cooling systems. Future nuclear power plants could take greater precautions by being built farther inland, getting extra quake-proofing protection, and perhaps being elevated above the danger of tsunamis.
"They could have placed [the Fukushima Daiichi nuclear plant] inland a mile or so and elevated," said Michael Constantinou, a civil engineer at the University of Buffalo in Buffalo, N.Y. "I am sure any replacement will consider these [factors] and will use seismic isolation."
Such seismic isolation systems protect crucial buildings by allowing for horizontal movement during an earthquake. Some look like stacks of rubber layers bonded to steel plates, while more advanced designs use lubricated sliders trapped between steel plates.
France has four reactors that use seismic isolators, and South Africa has two protected reactors. The U.S. Department of Energy has also included seismic isolators in its designs for next-generation nuclear power plants.
"I doubt there will be more nuclear power plants built in California," Constantinou told InnovationNewsDaily. "But we will build in U.S, and they will be seismically isolated."
Constantinou's group at the University of Buffalo and colleagues at the University of California-Berkeley were in the final phases of a proposal for the seismic isolation of next-generation nuclear power plants when disaster struck in Japan. They plan to submit the proposal soon to a U.S. government agency.
Seismic isolators have already been deployed in extreme engineering conditions, Constantinou said. He consulted on the use of seismic isolators in offshore oil and gas drilling platforms in the North Pacific that were designed to withstand both major earthquakes and huge waves of 33 feet (10 meters) in height above the ocean's surface.
"We have the technology," Constantinou told InnovationNewsDaily. "The key is to correctly interpret and select the seismic hazard [to be protected against]."
Japan's Nuclear Energy Safety (JNES) organized workshops in late 2010 to see how it could apply seismic isolation to its nuclear power plants. It also ran a three-year program with the International Atomic Energy Agency to study lessons from tsunami disasters.
"To prevent recurrence of major tsunami disasters in the future, issues related to the safety assessment of nuclear power plants with respect to tsunamis will be identified in lessons learned from past tsunamis, and recent approaches and future directions will be discussed," according to a JNES/IAEA symposium document.