As the horror of September 11 unfolded, the nation’s 103 commercial nuclear reactors and dozens of federal nuclear weapons facilities were put on high security alert. The U.S. government has long considered them potential terrorist targets, implementing programs to protect nuclear facilities against these threats. But is enough being done?

Ten days after large commercial jets slammed into the World Trade Center and the Pentagon, the Nuclear Regulatory Commission conceded that, “nuclear power plants were not designed to withstand such crashes.” As a result, the NRC concedes that a similar attack on one of the nation’s reactor stations could cause thousands of fatalities, and render large areas uninhabitable.

The public should be aware that some the largest concentrations of radioactivity in the world are contained in this country’s storage pools for spent reactor fuel rods. There are some 40,000 tons of spent reactor fuel stored in pools of water at almost all U.S. commercial reactor sites, collectively representing the single largest concentration of radioactivity on the planet.

Many pools store more spent fuel than the original designs intended. Moreover, the pools were designed only to serve as interim storage, under the assumption that the waste eventually would be disposed of elsewhere. Some pools are contained in corrugated facilities or with metal roofs. These buildings are not capable of withstanding a small plane crash, let alone a hijacked airliner.

The Nuclear Regulatory Commission has officially conceded that a catastrophic fire at the nuclear waste storage facility in Orange County, North Carolina–similar to the one at the Chernobyl reactor in 1986–could result in the release of 100% of its radioactive contents into the air. The radioactive strength of the spent fuel would be about 8 times greater than in a reactor core.

In the event of such a disaster, the geographic area that would have to be evacuated would be roughly the size of the entire state of North Carolina. Before September 11, federal nuclear regulators dismissed the likelihood of such a scenario, arguing it was impossible to predict acts of malice. Unfortunately, this scenario is no longer an abstraction, but storage facilities have not been improved.

Another danger is posed by the lack of adequate and safe storage for nuclear weapons production materials. Tons of nuclear materials, such as plutonium and highly enriched uranium, are either sitting outside, exposed to the elements, or in aged and deteriorating Department of Energy (DOE) facilities. Like those at nuclear power plants, these facilities were never constructed to withstand large jet crashes or in some cases, even the crash of a small plane.

The refusal by responsible programs to assume financial responsibility for the safe storage and disposition of dangerous nuclear materials–like highly enriched Uranium-233–continues to create delays. In particular, the DOE still has not decided whether the materials should be kept for future use or disposed of as waste.

Before September 11, both the Energy Department and commercial reactor owners had been slow to deal with this problem because of the expense. Since then, however, some experts are now contending that the chances of terrorist attacks against nuclear installations are small.

This is wishful thinking. A rapid effort to safely store the nation’s huge inventories of potentially vulnerable commercial reactor spent fuel and nuclear weapons materials should become a top security and public safety priority.

If the events of September 11 and since have taught us anything, it is that the war against terrorism will be an unpredictable struggle. The costs of fixing America’s nuclear vulnerabilities may be high, but the price of doing too little may prove far greater.