What are the odds of a nuclear accident in US?
A U.S. nuclear plant in Alabama similar in design to the earthquake-hit Fukushima facility in Japan has multiple defenses to prevent and tackle the same kind of emergency, its operator said.
Safety features at the Browns Ferry plant in northern Alabama are so superior to those at Japan's Fukushima Daiichi plant that even in the event of massive flooding the chances of a crisis were negligible, officials from the Tennessee Valley Authority (TVA) told reporters.
"What we have here is defense in depth, multiple levels of redundancy, backup to the backup to the backup," TVA communications consultant Jim Nesbitt told journalists who toured the facility on Friday as he explained the plant's elaborate safety systems.
The emergency at the Japanese plant has escalated since March 11 when a tsunami, triggered by a massive earthquake, knocked out power.
It has revived debate over U.S. nuclear safety just as the industry is set for its first expansion since an accident at the Three Mile Island nuclear facility in Pennsylvania in 1979. About 20 percent of U.S. electricity is supplied by nuclear power.
Japan's woes have focused attention on how far U.S. facilities are protected against one-off events such as terrorist attacks, earthquakes or flooding.
Comparisons between Fukushima and Browns Ferry are relevant because both have Mark 1 boiling water reactors made by General Electric. In total, there are 23 such reactors in the United States. [ID:nN24140384]
Some nuclear engineers deem these reactors more vulnerable than newer pressurized reactors to dangerous overheating in the event of power loss.
Critics point to objections raised by U.S. nuclear engineers in the 1970s and 1980s about possible design vulnerabilities in boiling water reactors and they say what happened at Fukushima merely validates those concerns.
"We've known since the 1970s that these designs are dangerous and now we've seen what can happen," Diane D'Arrigo, radioactive waste project director at the Nuclear Information and Resource Service, said in an interview.
Image shows Browns Ferry nuclear plant under construction. Note the large "doughnut" ring under the reactor vessel. Credit: Tennessee Valley Authority.