June 6, 2002
A new report commissioned by the Aircraft Owners and Pilots Association has concluded that general aviation aircraft do not pose a serious threat to the nation's nuclear power plants. The report by internationally recognized nuclear safety and security expert Robert M. Jefferson said that the crash of a GA aircraft wouldn't cause a dangerous release of radiation.
"Following the events of September 11, some expressed fears that a small aircraft might 'attack' a nuclear plant," said AOPA President Phil Boyer. "We sought out an expert to determine if those fears were real."
"The Jefferson report makes it clear that general aviation aircraft are not effective weapons, and small aircraft aren't a significant threat to the safety of the public when it comes to nuclear power plants."
In the report, "Nuclear Security—General Aviation Is Not a Threat," Jefferson said that if a general aviation aircraft were to crash into any part of a nuclear power facility, the "result of such an endeavor would fail to produce the damage necessary to cause any radiological involvement of the public."
Jefferson concluded that:
Sen. James Inhofe (R-Okla.) submitted the Jefferson report into the congressional record June 5 during a hearing of the Senate Environment and Public Works Committee, while Sen. Christopher (Kit) Bond (R-Mo.) said, "Commercial nuclear plants are probably the most physically secure and least vulnerable of our nation's industrial infrastructure. They are robust, hardened facilities with numerous redundant systems designed to assure public safety."
The Jefferson study concluded that a general aviation aircraft could not penetrate the concrete containment vessel protecting the nuclear reactor.
While few nuclear reactor facilities were designed specifically against threats from GA aircraft, that point is misleading, according to Jefferson. "It overlooks the fact that by their very design, nuclear power plants are inherently resistant to such strikes," he said.
All containment vessels are designed to withstand the impact of tornado-propelled "missiles." Tornados can pick up objects as large as cars and hurl them against buildings with tremendous force. In one test, a power pole was rammed into a containment wall at more than 120 mph without causing damage to the structure. "A power pole impacting perpendicular to the surface of the concrete is certainly a more effective missile than a light, aluminum general aviation aircraft," said Jefferson.
In another test, a 45,000-pound F-4 Phantom jet was propelled at 450 miles per hour into a concrete wall simulating a containment vessel. The aircraft was destroyed; the concrete wall was "uncompromised."
(An F-4 is 18 times heavier than a Cessna 172, the most popular GA aircraft. And even in a dive, a Cessna 172 can't go much faster than 200 mph.)
Even a large commercial airliner such as a Boeing 757 would not likely penetrate the outer containment vessel of a nuclear power plant. But even if it did, the reactor vessel, which contains the nuclear fuel, would remain intact, according to Jefferson.
Some have speculated that a light aircraft loaded with explosives might lead to a release of radiation. "The capabilities of light aircraft argue against such an attack being successful," Jefferson said.
Most GA aircraft have payloads of less than 1,000 pounds. Any explosives would have to be carried in the passenger or cargo compartments, far away from the nose of the aircraft. Even if a terrorist were able to rig a contact fuse on the nose of the aircraft, the explosion would be several feet away from the reactor containment building. That distance would reduce the damage to the point that even if the containment vessel were breached, there would be little or no damage to the reactor vessel inside, according to the nuclear expert. (Jefferson has been involved in full-scale testing of systems subjected to explosive attacks.)
Nuclear power plants are designed so that a "single failure" cannot cause the loss of critical safety systems. Support systems are not co-located at a single point. An aircraft crash could not destroy every safety and control system at once, Jefferson said.
"It is inconceivable that the crash of a general aviation aircraft could accomplish such broad safety problems in a nuclear power plant," said Jefferson.
Spent nuclear fuel is stored in massive shielding systems or in deep pools, covered with up to 50 feet of water. The pool walls are concrete and steel. The pool itself is a relatively small target. Even if the aircraft could hit the pool, it would not likely disturb the spent fuel.
To ignite the Zirconium cladding on the spent nuclear fuel, an aircraft would have to create a fire that would burn for about 20 hours, according to Jefferson. That would take some 176,000 gallons of aviation gasoline. The typical GA aircraft carries 60 gallons of gasoline.
Jefferson concluded that general aviation aircraft would "prove ineffective in an attack similar to those carried out on September 11.... The success of these attacks was predicated on the use of large, turbine-powered commercial aircraft with an immense fuel carrying capacity. A general aviation aircraft, at only a fraction of the weight, speed and fuel load, would be unable to inflict damage on the scale witnessed on that tragic day."
Robert M. Jefferson has more than 45 years experience in the nuclear field. Currently an independent consultant, his experience encompasses full-scale testing of systems subjected to explosive attacks, full-scale testing of spent fuel shipping casks, and the development of calculation techniques for assessing public impact of nuclear fuel cycle activities. The Sandia National Labs employed him for 27 years in the field of reactor and transportation safety research. He also teaches graduate-level nuclear engineering classes.
A copy of " Nuclear Security—General Aviation Is Not a Threat" is available online.
The 380,000-member Aircraft Owners and Pilots Association is the world's largest civil aviation organization. Some two thirds of the nation's pilots, and three quarters of general aviation aircraft owners, are AOPA members.
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