I had planned on spending this update reflecting on the retirement of Space Shuttle Discovery, but the ongoing meltdown of three nuclear reactors at Japan's Fukushima Nuclear Power Plant deserves a bit more attention. As the crisis unfolds, it's worth asking if anything more can be done to limit this disaster's effects, and whether a similar situation could occur within the United States (where 23 GE-built reactors of similar design are operating today.)
The Fukushima Disaster can undeniably be linked to Friday's tsunami, which may have killed as many as 10,000 people as it buffeted the Japanese mainland. While the reactors "scrammed" (shut down) as planned when the earthquake was first detected, the loss of power to the plant's coolant pumps led to their overheating and the eventual melting of fuel rods within the reactors. Fukushima is not typical of the way most nuclear plants behave during earthquakes; American nuclear plants have withstood earthquakes before without overheating. Diesel generators are supposed to drive the coolant systems until the reactor can be brought back online. It's likely that Fukushima's diesel generators were damaged by the tsunami. By this point it's almost certain that none of those three reactors will return to service, since the Fukushima plant officials have resorted to the desperate measure of pumping highly-corrosive seawater into the reactors to cool them.
The larger question is whether it's ever possible to completely disaster-proof a nuclear power plant. The anti-nuclear activists would say that it's not, and argue that there's no acceptable risk level when dealing with the small probability that a disaster such as Fukushima could happen.
"Acceptable risk" is important when considering the consequences of disaster, however unlikely they may be. This past spring & summer's oil spill in the Gulf of Mexico certainly made me reconsider whether our society should accept the remote risks of offshore drilling after seeing the consequences the spill created for the Gulf Coast. Will there be consequences after the Fukushima disaster? It's hard to say because of conflicting experts who have taken their message to the airwaves since this disaster started to unfold. Opponents of nuclear power argue that molten nuclear fuel, fission byproducts and other core materials will eat through the reactor's containment vessel and escape into the environment. Supporters of nuclear power generally believe that the molten materials will be contained, and any gases released will be largely harmless as they were during the Three Mile Island meltdown of 1979.
Just as the nuclear power industry appeared to be headed towards rebirth and growth around the world, the natural disaster of the tsunami is forcing policymakers to reconsider its views on nuclear power. I have no doubt that short-term measures will be taken to protect the diesel generators of many nuclear power plants in areas where there is risk of earthquake, tsunami and other natural disasters. There may also be new designs for venting the hydrogen gas which exploded and partially destroyed the outer containment buildings of the #1 & 3 reactors. If nuclear power is not stalled as a result of this accident, we may see a renewed push for safer reactor designs that rely on helium coolant and pebble-like fuel elements
As America and other nations continue to debate the role of nuclear power, it's important to take measured reactions to the disaster at Fukushima. With any technology there are risks we have to accept when it fails. Nuclear power is an important "bridge technology" between the coal-fired plants we've relied on for too long, and a faraway future of nuclear fusion. Practically-speaking, we will need to accept and minimize nuclear power's risks to meet our nation's energy needs well into the future.