WASHINGTON -- The Nuclear Regulatory Commission said yesterday that nuclear power plant operators should not be expected to stop terrorists from crashing an airliner into a reactor, saying that responsibility lies elsewhere.
Plant operators instead should focus on limiting radioactive releases and public exposure from any such airborne attack, the agency said in a revised defense plan for America's nuclear plants.
"The active protection against airborne threats is addressed by other federal organizations, including the military," the NRC said in a statement.
The agency rejected a proposal by a nuclear watchdog group that power plants be required to erect a "lattice-like" device or other barrier that would prevent an aircraft from hitting a reactor containment dome.
Details of the new defense plan are secret. The agency approved it by a 5-to-0 vote at a brief meeting at which the plan was not discussed publicly in any detail. The revised plan has been the subject of intense internal discussions for 15 months.
The NRC, in a summary of the security plan, said that "active protection" against an airborne threat rests with organizations such as the Federal Aviation Administration and the military.
It said that various mitigation strategies required of plant operators -- such as radiation protection measures and evacuation plans -- "are sufficient to ensure adequate protection of the public health and safety" in case of an airborne attack.
"This rule is an important piece, but only one piece of a broader effort to enhance nuclear power plant security," the NRC chairman, Dale Klein, said in a statement.
The new plan spells out what the operators of the nation's commercial nuclear power plants must be capable of defending against. It assumes that a terrorist attack force would be relatively small -- and that its weapons would be limited and not include rocket-propelled grenades or other weapons used by terrorists.
Critics of the NRC have said the revisions, which have been in the works for more than a year, do not fully take into account the threats to nuclear reactors in light of the Sept. 11, 2001, terrorist attacks.
"Rather than requiring measures to prevent a plane crash from damaging vulnerable parts of a nuclear plant . . . the government is relying on post-crash measures and evacuation plans," said Michele Boyd of Public Citizen's Energy Program, a nuclear industry watchdog group.
Senator Barbara Boxer, Democrat of California, in a letter to the NRC last Friday, said the agency's defense requirements should "ensure that . . . the plants are prepared to defend against large attacking forces and commercial aircraft."
Boxer is chairwoman of the Senate committee with jurisdiction over the NRC.
While NRC officials have all along declined to discuss specifics of the defense plan for nuclear power plants, formally known as the Design Basis Threat, it is known to assume a relatively small attack force of no more than a half dozen attackers.
NRC officials have emphasized that the defense plan should require what is "reasonable" to be expected of a civilian security force at the 103 commercial nuclear power reactors.
The nuclear power industry has argued that it would be unreasonable to expect them to guard against any attack that employed a large, hijacked aircraft. They contend that protection against that sort of attack -- or one using a large ground attack force -- should instead be a responsibility of the government.