Part of the Policy Perspectives Series
In this Policy Perspectives, Sharon Squassoni wries that the enormous earthquake and tsunami that hit Japan on March 11, 2011, triggered a crisis at the Fukushima Daiichi nuclear power reactors that is still unfolding, watched cautiously by millions across the globe. Three reactors have sustained damage to the fuel in their cores as a result of overheating; three have had hydrogen explosions that damaged the secondary containment buildings, blowing off roofs; and one is thought to have suffered damage to the primary containment as a result of a hydrogen explosion, among other things. Radiation levels spiked then dropped and the Japanese government ordered an early evacuation of the population around the Daiichi and Daiini plants. Low levels of water in spent nuclear fuel pools, particularly at Unit 4, have triggered fires with radiation releases. The Tokyo Electric Power Company (TEPCO), which operates the six reactors at the Fukushima Daiichi site, has estimated that 70 percent of the fuel at one reactor has melted and that 30 percent has melted at another reactor. TEPCO resorted to the unprecedented measure of injecting seawater into reactors, which virtually ensures they will not operate again because of corrosion.
Diesel generators should have provided power when electricity cut off, but these apparently were damaged by the tsunami, which TEPCO estimates reached 14 meters high. Systems to cool the cores that would not have relied on electricity but on steam reportedly worked for a while, but eventually succumbed to rising temperatures. Batteries eventually ran out. Without electricity to power the various instruments needed to make measurements, information about the reactor core has been difficult to gather. Damage from the earthquake and tsunami has hampered restoration efforts.
It is tempting to offer lessons learned from the crisis, as many observers already have. But the crisis is not yet over, and the full details of how it has unfolded and its ultimate impact are unknown. Japan and the rest of the world, including those countries that operate nuclear power plants and those that are considering an option for nuclear power, will pore over the details in time. It would be more useful at this point to analyze what this crisis is and isn’t before deriving lessons.
Is the crisis about a one-in-a-million event? No.
The question posed often in the media is “Can it happen here?” Some fear the possibility, but most likely believe that “it can’t happen here.” Humans like to reassure themselves that others’ tragedy cannot befall them. With the Chernobyl nuclear accident in 1986, it was relatively easy to do that, since many elements contributing to the widespread radiation contamination were unique to the situation, including a risky design that hindered shutdown of the reactor, the presence of graphite that caught fire, and the lack of containment. Many forget, however, that the operators were conducting a test of the back-up cooling system because they were concerned that the delay in starting the diesel generators (75 seconds) was too long in a crisis scenario.
The Fukushima accident represents a concatenation of natural disasters and man-made errors. Reactors are designed to withstand limiting fault conditions—events estimated to occur only once in 10,000 reactor-operating years, such as earthquakes, floods, or terrorist activities. Accidents that are beyond the design basis, such as simultaneous “design basis accidents”—earthquakes and floods—are thought to be unlikely, put on a par with asteroids.
It is tempting to conclude that such a large earthquake followed by a tsunami will not happen again. And that could be true. But the real issue is that power reactors and their spent fuel pools face high risks from “station blackouts”—the lack of both off-site and on-site electricity to the plant. According to the U.S. Nuclear Regulatory Commission, risk analyses performed for nuclear power plants indicate that the “loss of all alternating current power can be a significant contributor to the risk associated with plant operation, contributing more than 70 percent of the overall risk at some plants.” All irradiated fuel needs to be cooled and contained, but no one predicted events that would overwhelm the multiple backup systems in place. Japanese battery capabilities reportedly last from four to eight hours; U.S. battery capabilities are similar.
A 2005 study done by Idaho National Laboratory shows that while the frequency of losing offsite power has decreased for U.S. plants, the duration of those events has increased. Improved emergency diesel generator performance—exactly what failed in the Japanese case—was thought to contribute to a reduction in core damage frequencies.
Is the crisis about whether nuclear power is safe? Yes and no.
Nuclear power accidents tend to evoke strong public and government responses in ways that accidents across the energy sector do not. Despite severe accidents in the oil, gas, coal, and hydropower sectors, one rarely hears of widespread responses to them. In the nuclear sector, however, the mantra is that “a nuclear accident anywhere is a nuclear accident everywhere.” Public uneasiness about nuclear power could stem from the large number of evacuees involved in serious nuclear accidents, a vague fear of a threat that cannot be seen, or an aversion to consequences that could affect future generations.
The Fukushima accident has prompted several countries to announce safety reviews, including the United States. China, which is currently building the largest number of power reactors, has announced a temporary halt in construction. Germany has taken the precaution of shutting several reactors down pending a safety review, an action that has significant economic costs.
One outcome of the accident is likely to be more stringent regulation and therefore higher costs for nuclear power. The question isn’t whether nuclear power is worth the risk, but whether it’s worth the cost of doing it better. At existing reactors, this could affect decisions to repair or replace aging components or even delay action until it is necessary. It could also lead to lapses in reporting safety problems, as has been the case with TEPCO in the past. With an estimated cost of $1 million for every day a plant is shut, there can be considerable pressure to keep large nuclear power plants open.
Costs are even more of a concern in building new power plants. The additional safety features of French-designed European pressurized reactors (EPRs)were questioned in 2009 when the United Arab Emirates opted to purchase less costly Korean reactors. Although fewer today might question the need for extra containment, the cost of the EPR has continued to climb. Will the safest designs be affordable and are the safest designs safe enough in light of Fukushima?
Is the crisis about fear of radiation? Yes.
The Fukushima crisis has heightened the public’s concern about radiation, even though the effects so far have been mostly local. It is clear that the restoration effort has been hampered by significant radiation on site and that some radiation has made its way into local agriculture and seafood, which could have a significant economic impact. Public fear of radiation, whether proportional to the risks, is a fact and one that must be considered in plans to expand nuclear power. If expansion is to be done sustainably, nuclear facilities will need to be sited through a consultative process in which the public will have to have confidence. This is also true for nuclear waste management and disposal.
Is the crisis just about the reactors themselves? No.
The events at Fukushima highlight the vulnerabilities also of spent nuclear fuel (SNF) pools. Although concerns have tended to focus on melting fuel in reactors and the potential for breaches in containment, the risks of overheating fuel in SNF pools have also been illuminated in this crisis: metal cladding caught fire in Unit 4, and smoke could contain radioactive particles. Spent fuel, without tons of water to cool it and provide a radiation barrier, has been very difficult to control. TEPCO has resorted to spraying seawater at the pools at Units 3 and 4 from helicopters and now from specially engineered trucks. The practice of leaving spent nuclear fuel in wet storage at reactors may now be questioned more. Some may urge reprocessing as a way of minimizing at-reactor SNF storage, but this is costly, creates additional waste streams, and is likely to result in more stockpiles of separated plutonium that pose nuclear security risks. Others will urge moving more spent fuel to dry cask storage. At a bare minimum, the public may now be more sensitized to the fact that nuclear waste doesn’t just disappear—it must be monitored in the interim and stored safely and securely for hundreds of years. This last challenge is one that no single nation has yet conquered.
Sharon Squassoni is a senior fellow and director of the Proliferation Prevention Program at the Center for Strategic and International Studies in Washington, D.C.
The Center for Strategic and International Studies (CSIS) is a private, tax-exempt institution focusing on international public policy issues. Its research is nonpartisan and nonproprietary. CSIS does not take specific policy positions. Accordingly, all views, positions, and conclusions expressed in this publication should be understood to be solely those of the author(s).
© 2011 by the Center for Strategic and International Studies. All rights reserved.