Like many of us, Brian Wirth, UTK-ORNL Governor’s Chair for computational nuclear engineering, has been following the nuclear crisis in Japan closely. But unlike many of us, the situation is inextricably linked to his position as a leader in U.S. Department of Energy research projects that investigate the performance of nuclear fuels and structural materials in nuclear environments.
“In both accidents, the cooling water was partially uncovered from the fuel and caused fuel damage, partial fuel melting and release of fission product gases from the fuel,” he said. “Even though the cause of the accident is very different, there are three reactors involved at Fukushima Dai-ichi, and in fact, the power levels and heat generation within the reactors at Dai-ichi was much less than at Three Mile Island, since the Japanese reactors shut down the fission process immediately following the earthquake.”
However, the Fukushima accident is categorically different from Chernobyl.
“With Chernobyl, a violent explosion and fire vaporized the fuel and all of the fission products, resulting in dispersal to the atmosphere because of the lack of a reactor containment structure,” he said. “The radioactive releases at Fukushima are many, many orders of magnitude lower than at Chernobyl, as are the radioactive doses to the workers on site.”
Wirth said the U.S. has 31 General Electric boiling-water reactors in operation that are of the same design as those at Fukushima Dai-ichi. He noted the safety of these reactor designs will likely be re-evaluated in the context of lessons learned from the Fukushima incident.
In fact, he said now is a good opportunity to have a different conversation about nuclear energy.
“The Fukushima incident can and should be a catalyst for a pragmatic discussion regarding the risks associated with the various technologies used for the production of electricity,” said Wirth. “To be sure, there is no magic bullet energy technology to generate large-scale, reliable and inexpensive electricity; coal is cheap but dirty, and mining is not necessarily safe; natural gas is cheap, but carbon dioxide emissions are high; nuclear is expensive, and although it has low carbon dioxide emissions, there will be safety concerns. Solar and wind are more expensive and less reliable and therefore require coincident deployment of batteries that also bring significant environmental impacts. The conversation should focus on a cost-benefit analysis of a diverse energy portfolio.”
One potential lesson to be drawn from Fukushima is the real-time expiration of reactors. Wirth, who examines the effects that decades of extreme temperatures and constant radiation have on specific reactor materials, explained how lifetime extensions for aging infrastructure have been pursued rather than replacing older reactors with more modern designs largely due to the capital cost necessary for example, to build a new power plant — approximately $10 billion.
“In the case of Fukushima Dai-ichi Unit 1, it was originally scheduled for decommissioning at the end of March 2011 but recently received a 10-year license extension,” he said. “Perhaps a lesson to heed from Japan is the cost of not acting. This applies not only to energy production, but transportation infrastructure as well.”
Wirth said energy technology will never be completely fail-safe, as evidenced by recent events involving fossil fuels such as the Upper Big Branch, W. Va., coal mine explosion in April 2010 killing 29 miners, natural gas pipeline explosion in San Bruno, Calif. in September 2010 killing nine and the Deep Water Horizon explosion and oil well leak in the Gulf of Mexico in April 2010 killing 11 and causing untold damage as the worst offshore oil spill in U.S. history.
He suggests a balanced energy debate should focus on a cost-benefit analysis based on the impossibility of zero-risk for any energy source.
“Ultimately, a pragmatic cost-benefit analysis of nuclear energy should be compared to similar cost-benefit analyses of other energy sources, where risks and costs associated with all energy sources are openly discussed, with a clear intention to reduce both the environmental impact and our reliance on politically unstable regions for energy.”
Wirth was named Governor’s Chair in 2010.