Years will pass before we fully understand what happened at the Fukushima nuclear power plants. Nonetheless, broad lessons can be learned based on information available.

Lesson One: Human error is a far greater threat than technology.

Unforeseen natural disasters happen, and catastrophes sometimes result. That, however, cannot be used as an excuse. Indeed, an initial review of information indicates that human error was the real culprit. The actual reactors at Fukushima worked. Nuclear reactions stopped in each reactor upon the earthquake strike, and backup power took over when primary power was lost. The problems really began as systems broke down when multiple tsunami waves overcame the safety designs of the site.

Unfortunately, many of the problems were likely preventable. According to the International Atomic Energy Agency, the plants' tsunami barriers were identified as insufficient, but Japanese regulators had never fully approved modifications to fix the problems. Given this, the plants' backup power sources should have been housed in flood-proof locations. In fact, all were vulnerable to flooding, which left 11 of 12 generators unworkable.

Additional design problems also emerged. It remains unclear exactly how Japanese officials addressed some well-known reactor steam and pressure venting issues. What is known is that the reactors had venting problems. While hydrogen-containing steam was released from the reactor's primary containment, valve malfunctions allowed it to migrate back into the reactor building. This accumulation of hydrogen caused the explosions, which then apparently led to additional severe challenges, such as those associated with the spent fuel pools.

An incoherent command structure, where real-time decision making authority was spread among multiple individuals, made managing these conditions even more difficult. Not having a single person on the ground and in charge diminished the influence of those with the most relevant experience. Instead, some critical decisions, such as when to vent steam from the reactors or when to use seawater to cool them, seemed to be pushed up to authorities with more political than technical experience.

Lesson Two: The American safety regulation system for existing plants works.

The Nuclear Regulatory Commission sets the safety standards and strictly enforces them with on-site inspectors and ongoing oversight. The Institute for Nuclear Power Operators, a private safety organization, adds another layer of safety by providing training, best practices, and plant-specific safety audits. Finally, each plant operator is responsible for maintaining safe plant operations.

The U.S. system allows regulators and plant personnel to effectively identify and mitigate safety deficiencies while maintaining efficient operations. That is why America's nuclear power plants not only enjoy exemplary safety records but produce some of the most affordable electricity.

Lesson Three: The United States must fix its system for nuclear waste disposal.

Our lack of a nuclear-waste disposal policy is causing U.S. power plants to collect more spent fuel in pools than they were ever engineered to hold. While safe, should a plant ever face an emergency like that in Japan where pool integrity was threatened, the additional spent fuel could increase the safety risk. It is an unnecessary, federally imposed risk that could be mitigated by opening Yucca Mountain.

Lesson Four: Radiation remains a great unknown.

We need to learn more about radiation. While this lack of understanding makes nuclear power scary to most people under normal circumstances, it can cause panic during an accident. This panic affects the public and policymakers. The public can become fearful and behave irrationally, such as buying iodine pills in the United States to protect against an accident in Japan. Policymakers can act irrationally as well, as when German officials called to shut down all of their reactors. The media exacerbates the problem by writing stories that play on public fear instead of educating people about the events and their impact.

Spewing so much radiation into the ground, atmosphere, and water is not good, but we need to better understand how bad it actually is. This will allow us to respond to future accidents more effectively and place the risks of future nuclear power into a more realistic context. Additionally, the IAEA has concluded that no lasting human impact will result from the radiation released from Fukushima.

Lesson Five: An accident has not stopped the expansion of nuclear power.

This is perhaps the most telling lesson learned from Fukushima. While a few nations stated that they would either not pursue new reactors or shut down their existing ones, the fact is that support for nuclear was already waning in those places. The consensus among most was that a commercial nuclear accident anywhere threatened progress everywhere.

Given the severity of the accident at Fukushima—and that it happened in Japan, a nation widely held as a leader in commercial nuclear safety—few could have predicted that the nuclear renaissance would largely stay on track in its wake. Yet that's exactly what's happening. Progress on new plants in Georgia, South Carolina, and Tennessee continues, and reactor designers continue to pursue NRC licensing for their concepts.

In the end, we will undoubtedly learn many lessons from Fukushima. But it is important to understand that Fukushima was not America's accident. The United States had its accident at Three Mile Island and learned immensely from it. Indeed, the way our industry is organized is a direct result of those lessons. Fukushima was Japan's accident, but we both can learn from it.

Jack Spencer is a nuclear energy policy research fellow at the Heritage Foundation.