Nuclear Safety and Terrorism
By Robert Alvarez

As the horror of September 11th unfolded, almost immediately, the nation's 103 commercial nuclear reactors were put on high security alert. For decades nuclear power plants have been considered as prime terrorist targets and programs are in place to protect them against these threats. But, is enough being done?

Although reactor containments have been a focus of concern, nuclear spent fuel pools are considered to be more vulnerable to acts of terror and may well pose the most severe consequences. Reactors are inside steel vessels surrounded by heavy structures and containment buildings. On the other hand, spent fuel pools, containing the single largest concentration of radioactivity on the planet, can catch fire and are in much more vulnerable buildings.

Over the past 25 years, citizens, state and local governments have forced nuclear safety regulators in the United States and Europe to concede that spent reactor fuel ponds pose catastrophic dangers. A loss of water exposing spent fuel could lead to a catastrophic fire with severe consequences, potentially much worse than a reactor melt down. Once the spent fuel in a high-density pool, which is the case for nearly all U.S. reactor stations, is exposed to air and steam, the zirconium fuel cladding would undergo an exothermic reaction and catch fire at about 1000 degrees C.

After the onset of a fire, the fuel pool building would not likely withstand the conflagration; and the fire is likely to spread to nearby pools. The NRC concedes that such a fire cannot be extinguished. It could rage for days.

Spent fuel pools on the average hold five to ten times more long-lived radioactivity than a reactor core. Of particular concern are the very large amounts of cesium-137 in fuel pools, which contain anywhere from 20 to 50 million curies of this dangerous isotope. With a half-life of 30 years, Cs-137 gives off highly penetrating radiations and absorbs in the food chain as if it were potassium. According to the NRC as much as 100 percent of the pool's Cs-137 inventory, in the event of a fire, would be released to the environment.

By comparison, in 1986, the Chernobyl reactor accident released about 40 percent of the reactor core's inventory of 6 million Curies of Cs-137 to the atmosphere. This isotope is responsible for most of the accident's very large offsite radiation exposures. There is more Cs-137 in a single spent fuel pool than was deposited by all atmospheric nuclear weapons tests across the Northern Hemisphere.

For instance, if a fire were to occur at the Millstone Reactor Unit 3 pool in Connecticut, it could render about 29,000 square miles of land uninhabitable. Connecticut occupies about 5,000 square miles, and since the Millstone station is 12 miles away from New York, it could severely impact Long Island and possibly New York City.

A 1997 report for the NRC by Brookhaven National Laboratory also found that a severe pool fire could cause as many as 28,000 cancer fatalities and $59 billion in damage.

Loss of pool water could occur as a result of several events including leakage, evaporation, siphoning, pumping, an aircraft impact, earthquake, an accidental or deliberate drop of a fuel transport cask, a severe accident at the reactor, and an explosion inside or outside of the pool building.

Industry officials are quick to point out there will be sufficient time for personnel to provide an alternative cooling system and other actions before spent fuel catches fire. But, once the water level drops to just a few feet above the spent fuel, radiation doses in the pool building will be lethal.

The ability of fuel handlers to recognize problems, repair heavily damaged equipment, and take extraordinary efforts to command offsite resources has yet to be tested. But, if routine operations are any indication, not all reactors have pool temperature instruments and control room alarms. According to the NRC, the Indian Point 1 spent fuel pool near NYC is cracked and leaking, the freezing of pipes at the Dresden 1 reactor near Chicago in 1994 nearly caused a major drainage of pool water, and significant temperature rises in fuel pools have gone undetected for days.

For some 20 years, the NRC assumed aged spent fuel that has had several years for radioactive isotopes to decay, bore no risk of catching fire. But in an October 2000 study of spent fuel risks at decommissioning reactor sites, the NRC conceded, "the possibility of a zirconium fire cannot be dismissed even many years after a final reactor shutdown."

Safety equipment installed to allow increased spent fuel storage exacerbates the potential for spent fuel pool fires, particularly for aged spent fuel. In high-density pools, fuel assemblies are packed about 9 to 10.5 inches apart for PWR fuel--slightly more than the spacing inside a reactor. The NRC's October 2000 report points out that pool safety equipment could collapse from a major impact and obstruct air and water flow to exposed fuel assemblies that would then catch fire. The remaining water would generate steam, and interact with the zirconium, making the problem worse by yielding flammable and explosive hydrogen.

Perhaps the most important concession was made in June, 2001 when the NRC staff reported to the Commission that terrorist threats against spent fuel pools are credible and cannot be ruled out. "Until recently, the staff believed that the [design basis threat] of radiological sabotage could not cause a zirconium fire. However, [NRC's safety policy for spent fuel storage] does not support the assertion of a lesser hazard to the public health and safety, given the possible consequences of sabotage…"

Despite these important recognitions of spent fuel pool dangers, the NRC's ability to adapt to a much more dangerous world remains to be seen. The first public response by the NRC ten days after the attacks was a press release that said, "nuclear power plants were not designed to withstand such crashes." While it was widely covered by the news media as a major concession, in fact the NRC was actually restating its long-standing safety policy.

In 1982, the NRC's Atomic Safety and Licensing Board ruled that reactor owners, "are not required to design against such things as … kamikaze dives by large airplanes. Reactors could not be effectively protected against such attacks without turning them into virtually impregnable fortresses at much higher cost."

This view is buttressed by NRC's equally long-standing policy that blocks consideration of terrorist acts in licensing proceedings. Since highly destructive acts of malice cannot be predicted, the NRC reasons they are not germane to safety requirements. Incredibly, a day after the September 11th attacks, the NRC ruled that terrorist concerns raised by Georgians Against Nuclear Energy (GANE) regarding the mixing of plutonium in nuclear fuel at the Department of Energy's Savannah River Plant were not valid because "GANE does not establish that terrorist acts ... fall within the realm of 'reasonably foreseeable' events."

But, will more gates, guards, and guns be enough?

There are about 40,000 tons of nuclear spent fuel stored in pools at the nation's 110 operating and closed reactor sites with over 2 billion curies of long-lived radioactivity. Over the next several years the Energy Department estimates that storage space will be needed for an additional 11,000 tons.

For instance, the Millstone Nuclear Power Station in Connecticut currently has 585 fuel assemblies in the reactor Unit 3 pool, containing about 31 million Curies of cesium-137. Millstone's owner, Dominion Nuclear Connecticut Inc. is seeking permission from the NRC to expand storage in this pool until eventually it would contain 1,860 assemblies with about 74 million Curies of cesium-137.

The pools were designed to temporarily store a small fraction of the spent fuel that they currently hold. "Neither the AEC [now the Department of Energy] nor utilities anticipated the need to store large amounts of spent fuel at operating sites," stated Millstone's owner in October 2001. "Large scale commercial reprocessing never materialized in the United States. As a result, operating nuclear sites were required to cope with ever-increasing amounts of irradiated fuel… This has become a fact of life for nuclear power stations."

The major assumption underlying NRC's policy to allow ever-increasing amounts of spent fuel to be placed in pools, is that eventually the U.S. government will take this material for disposal, as required under the 1982 Nuclear Waste Policy Act. But, the Department of Energy will not accept custody of spent fuel until the year 2010, at the earliest, if at all. Even if the DOE and the Bush administration are able to overcome the formidable opposition to opening the Yucca Mountain repository in Nevada, what will be the risks of transporting thousands of shipments to Nevada, in the aftermath of September 11th?

In light of the NRC's recent admissions about spent fuel vulnerabilities, it appears that it is easier to drain a spent fuel pool and cause an accident than it is to penetrate and release the radioactive contents of multiple and widely spaced concrete and steel dry storage casks. Casks and other fuel storage alternatives are available that would greatly reduce, or even eliminate the risk of a pool fire. But only a handful of reactor owners have put about 4 percent of the nation's spent fuel into dry concrete and steel storage casks.

The pressures being felt by reactor owners from electricity deregulation work against putting spent fuel into hardened dry storage casks. According to a report about utility deregulation and nuclear power by the Nukem Corporation, "In an era of deregulation there will be no pool of captive customers to shoulder uneconomic operating costs or massive capital additions." As a result of deregulation limited liability companies now own many reactors with little or no cash reserves. Under these circumstances, funds necessary for storage of spent fuel into hardened dry storage modes heighten the conflict between profit and safety.

Other nations are taking spent fuel vulnerabilities very seriously. Currently Germany is actively seeking ways to further harden its dry stored spent fuel into even more robust containers. The French have installed anti-aircraft missiles around their spent fuel pools at the La Hague reprocessing facility, where some 100 million curies of Cs-137 are stored. What the United States will ultimately do to protect public safety from this serious nuclear vulnerability is still an open question.

Nonetheless, it now appears that the permanent disposal of commercial reactor spent fuel has become much more of an abstraction than a terrorist attack against a nuclear power station. The safe and secure storage of spent fuel in pools never intended to hold so much radioactive material indefinitely, should become a high public safety priority. If the events of Sept. 11th 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 spent fuel vulnerabilities may be high, but the price of doing too little may prove far greater.

Robert Alvarez is a Senior Scholar at the Institute for Policy Studies.

This page was last modified on Monday, January 21, 2002 4:12 PM
Contact the IRC's webmaster with inquiries regarding the functionality of this website.
Copyright © 2001 IRC. All rights reserved.