OS ANGELES
The Nuclear Regulatory Commission has quietly issued new security standards that nuclear power plants must meet to defend against terrorist attacks. If this was intended to help people living near the plants sleep more soundly, it was a dismal failure. The few specific improvements the commission made public were unambitious, and it kept secret its "design basis threat" — the elaborate set of rules spelling out the most likely terrorism attacks that the reactors must be protected against.

The new rules did include some sensible if limited new criteria on the hiring and use of security guards, and required other steps to "enhance" the power plants' security strategies. But the design basis threat is the centerpiece of the government's antiterrorism effort — and in a break with tradition, the commission refused to make public even its nonclassified elements.

Keeping the terrorists guessing about our defenses was presumably one motivation for the secrecy. However, it might also reflect the commission's desire to play down its acquiescence to the nuclear industry's hubristic view that the plants are nearly invulnerable.

Washington has long been reluctant to impose burdensome requirements based on hypothetical threats. In 1982, for example, federal authorities declared that nuclear plants need not defend against kamikaze attacks by airplanes — the cost, it was determined, outweighed the risks.

In 1985, I was one of several experts on military sabotage who appeared before the commission's advisory board on reactor safeguards to make a case for tightening the standards. We argued that the existing rule — which required utilities to be prepared only for an attack involving a handful of terrorists using handheld weapons — did not address the emerging terrorist risk. Our presentation was met with ridicule. One member scoffed: "Now it's truck bombs. What are you going to require us to do next, defend against attacks by aircraft or boats?"

In 1994, after the first World Trade Center bombing, I again appeared before the commission to discuss evidence that the terrorists had also contemplated attacks on reactors. I argued against the commission's presumptions — especially the idea that there would be timely warning before any attacks. It did finally concede that the risk of truck bombs should be taken more seriously. However, any changes made to heighten security against truck bomb attacks were kept secret. (Likewise, if the commission is intent on keeping the new rules classified, it should at least be prepared to tell us they will protect against the devastating types of bombs used this month in Saudi Arabia.)

In subsequent years public policy groups like the Nuclear Control Institute and the Committee to Bridge the Gap pressed the commission to change other elements of the design basis threat. Yet when the commission finally revisited the issue seriously after 9/11, it excluded any input from those public groups that had pointed out the inadequacy of standards in the first place.

Instead, it worked only with cleared government agencies and the energy industry itself — the same companies whose most significant step after 9/11 was to require their ill-prepared security guards to work exceedingly long hours.

Guards from several of the reactors told a watchdog group, the Project on Government Oversight, that they felt they were incapable of resisting a ground assault. The regulatory commission says it will work to improve these security systems by conducting mock attacks. However, the results of these exercises will not be released to the public and no fines will be levied for initial failures. In past drills, the mock terrorists have succeeded at nearly half the plants tested — though the utilities were given months to prepare and even told the dates the attacks would come. And following such exercises, utilities are likely to ratchet down plant security — the assumption being that there will be similar advance warning before a real attack.

The new rules may be a reaction to 9/11, but the commission doesn't seem to have learned the lesson of those attacks — not a thing will be done to reduce the vulnerability of reactors to strikes from the air. Some senators are talking about bypassing the commission and legislating new standards. This might be a long-term fix, but such laws would take take years to write, enact and put into effect. For now, Congress should demand a full public accounting of the commission's latest standards and ensure that it start meeting the security requirements of the post-9/11 world.

Bennett Ramberg, a former policy analyst at the State Department, is author of "Nuclear Power Plants as Weapons for the Enemy."