On Air Attack and Nuclear Power Plants

From today's edition of the New York Times:

With construction of many new nuclear reactors under discussion, the Nuclear Regulatory Commission is grappling with the question of whether they should be designed to withstand a Sept. 11-style airplane attack.

The commission has told its staff to study the vulnerabilities of the four new reactor designs, two of which it has already approved. But it has decided not to make the nuclear power industry meet security requirements any tougher than those for existing plants, which were designed before suicide airliner attacks, and even before the development of such airplanes.

Planes are not on the list of weapons that reactors must be prepared to survive. One of the five commissioners, Gregory B. Jaczko, has called for the panel to require design changes to reduce vulnerability, but the other four seem unpersuaded.

One of my colleagues, Adrian Heymer, is also quoted:

At the Nuclear Energy Institute, the industry's trade association, Adrian Heymer, senior director for new plant deployment, said designers had analyzed existing plants and made many changes that cost little but made the new designs more difficult to attack. But, in general, Mr. Heymer said, protecting against terrorism was a government function.

"“Refineries, tall buildings, those are the responsibility of federal government to protect,"” he said.

In 2002, EPRI conducted a study on the topic:

EPRI aircraft crash building integrity study uses advanced computer modeling and adverse assumptions. In 2002, the independent research organization EPRI undertook an advanced computer modeling study to determine if buildings at nuclear power plants can withstand the impact of an aircraft crash similar to the Sept. 11 terrorist attacks. A Boeing 767 was selected as the aircraft because its weight is greater than almost all other commercial jet airliners flown in the United States, and because over two-thirds of the commercial aircraft registered in this country are manufactured by Boeing. The location of the buildings and facilities where the aircraft would do the most damage was chosen as the place where the aircraft would strike. The study used the reasonable, controllable aircraft speed for the accuracy of the strike analyzed.

Nuclear plants are much smaller than the World Trade Center or the Pentagon, making them more difficult targets to strike by aircraft. Because nuclear plant structures are smaller than the buildings attacked on Sept. 11, they are more difficult to damage, because it is more difficult to aim the airplane such that it hits the structure at its most damaging point. In addition, used fuel storage pools are either deep within a building or the used fuel is located underground and thus not visible to a pilot from a plant'’s exterior. Also, intervening structures on the power plant site make it very difficult to reach these areas by plane. Finally, nuclear plant buildings and structures are so low to the ground that the ground begins to affect the wind currents produced by the plane, reducing a pilot'’s ability to control and maneuver the plane without slowing down.

The EPRI study demonstrates that the critical structures of a nuclear power plant will not be penetrated by a aircraft crash. The results of the EPRI study demonstrate that no parts of a Boeing 767 --—the engine, the fuselage, or the wings, nor the jet fuel -- —will enter the containment building, used fuel storage pool, used fuel dry storage facilities, or the used fuel transportation containers. This means that no radiation will leak from these structures even if hit by a Boeing 767 at the maximum plausible force and vulnerability.

For more on the study, which EPRI conducted at the request of NEI, click here. For more on safety and security at nuclear power plants, click here.

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