U.S. Weighs Whether To Build Some New Nuclear Warheads

Idea Is to Replace Aging Ones With More Reliable Type; Critics Dispute the Need
By Carla Anne Robbins
Wall Street Journal
December 14, 2005

LOS ALAMOS, N.M. -- On this remote mesa where the atom bomb was born, a fresh question is in the air: Does the U.S. need new nuclear weapons?

Some 15 years after the Cold War, and at a time when the U.S. is demanding others restrain their nuclear ambitions, the Bush administration thinks the answer is yes. With little notice, it has been pressing Congress to fund research into a new generation of nuclear weapons.

Lawmakers have twice turned down proposals to design a new nuclear "bunker-buster" bomb, to blow up buried caches of weapons. But last month, with little debate, Congress approved $25 million for research into what is supposed to be a sturdier, more reliable warhead than those designed during the Cold War. If the work is successful, the U.S. could someday spend billions of dollars replacing much of the current arsenal.

The U.S. hasn't designed or built a new nuclear warhead since the late 1980s. It hasn't tested one since 1992. U.S. officials say the aging arsenal is becoming increasingly difficult and costly to maintain, and was designed to deter a foe far different from those the U.S. now faces. "You would not create the current stockpile if you were starting now," says Linton Brooks, head of the Energy Department's National Nuclear Security Administration, which maintains the arsenal.

President Bush has committed to deep cuts in the U.S. nuclear arsenal. The overall stockpile numbers are classified. But by 2012 the cuts would leave the U.S. with about 2,200 nuclear warheads deployed on long-range launchers, along with some 700 short-range weapons. In addition, the Pentagon is expected to keep some 3,000 backup warheads, as a hedge against technical failures or a resurgent Russia. Mr. Brooks says with a more dependable warhead, along with a revival of the weapons-production complex, the U.S. should be able to make "significant" cuts in the hedge.

Critics say any international perception that the U.S. is strengthening its nuclear capability with new warheads could severely undercut its credibility at a time when it is pressing North Korea and Iran to curb nuclear appetites. "You cannot tell people that nuclear weapons are bad for you but we are modernizing ours," says Mohamed ElBaradei, head of the International Atomic Energy Agency.

Some also question the technical rationale. Currently, the U.S. spends billions of dollars each year to monitor its stockpile and extend the weapons' life. Critics say some minor changes in this maintenance effort could buy even more time.

Some also say any plan to build new warheads without testing them -- which is the administration's declared goal -- could leave more doubt, not less, about the arsenal's reliability. "We'll have to see how much of a change they're proposing, but it's hard to understand how a redesigned warhead that's never been tested would give you higher confidence than warheads which have been tested more than a thousand times," says Sidney Drell, a Stanford University physicist and member of the Jasons, a scientific group that advises the government on weapons issues.

Scientists at Los Alamos are engaged in their own vigorous debate. Joe Martz, a chemical engineer, heads a small team working on a preliminary design for a more-reliable warhead. He says new technology should permit crafting one that is easier to build, cheaper to maintain and safer to store, and that wouldn't need testing. At the same time, he fiercely opposes the Pentagon's proposed nuclear bunker-buster, saying any change that might make it more tempting to use nuclear arms would be "destabilizing."

When the Defense Department chose this spot in late 1942 as the site for its secret atom-bomb program, there was little here but farms and the Los Alamos Ranch School, built to toughen up sickly East Coast boys. The military put up a barbed-wire fence around the newly created town, then an interior fence around the lab itself, to keep the work secret even from scientists' families.

Reminders of that history are never far away. Los Alamos, now a town of 18,000, has an Oppenheimer Drive (after J. Robert Oppenheimer, head of the Manhattan Project), a Trinity Drive (after the desert site of the first test) and two atomic-bomb museums.

Inside the lab's security fences today, scientists are focused on more recent history and what they fear is a steady erosion of skills. "The really scary thing is that there are only two designers [of warheads' plutonium triggers] left at the laboratory who have underground-test experience," says James Peery, one of the weapons program's directors.

The U.S. got out of the business of making nuclear weapons almost by inadvertence. By the late 1980s, the Cold War was winding down and the once-sacrosanct weapons complex began to face public scrutiny. Under pressure from Congress and environmental groups, the Energy Department admitted in 1988 to causing radioactive and toxic pollution at installations in a dozen states.

The next year, federal agents, looking into allegations of illegal dumping and falsified records, raided and closed Colorado's Rocky Flats plant, which produced all of the arsenal's plutonium triggers. Then the first President Bush, amid his unsuccessful 1992 re-election campaign, reluctantly agreed to a congressionally mandated moratorium on testing.

A reprieve of sorts came in the mid-1990s. The Clinton administration, committed to a test-ban treaty that the Senate never did ratify, agreed to spend billions at the labs for technology to ensure the nuclear stockpile's continued reliability without test explosions.

Even after more than 1,000 test blasts, scientists had a limited understanding of what happens inside a nuclear warhead in the few billionths of a second as it explodes. They had still less experience with the effects of aging on warheads that once were replaced every 15 or 20 years. Today, in a program known as stockpile stewardship, the U.S. uses elaborate machines to try to determine how well its aging nuclear arms would work if the U.S. ever needed to detonate one.

A 220-foot-long electron accelerator, housed inside a thick concrete blockhouse here, produces some of the world's most powerful X-rays to photograph the inside of a mock nuclear warhead as it's subjected to the searing heat and pressure of a conventional explosion. Supercomputers then extrapolate the resulting data to gauge how the components would hold up under the far greater extremes generated by a nuclear chain reaction.

On a recent morning, scientists provided a taste of what their mix of real and virtual testing can do. They used computers to simulate the stress on foam used to hold a nuclear warhead together for the few microseconds needed to ensure that its series of explosions goes off.

Inside a small room called the Cave, engineers projected a greatly magnified three-dimensional model of the foam's cellular structure as it was compressed by a virtual nuclear explosion. Projected on the floor, ceiling and three walls, the yellow foam's branches, looking like undersea coral, sprouted dots of red as the foam began to break down under the pressure. The engineers then replayed this slowed-down virtual explosion, rotating the foam and the blast direction to get a view from all sides. The process enables them to see whether the foam holds up without setting off a warhead to find out.

The stewardship program has given the labs enough confidence that it plans to begin replacing certain aging components of a 30-year-old warhead called the W-76, the most numerous one in the arsenal. The plan is to extend its life another 30 years.

Still, the Bush administration came to office questioning how long this arsenal could be maintained without new testing, and determined to revive the weapons production complex and begin developing new warheads. A 2001 review identified a new set of potential adversaries, including Iraq, Iran, North Korea, Syria and China. It called for a broader array of nuclear capabilities, including weapons that could go after hardened, deeply buried targets, and less-powerful warheads to reduce "collateral damage."

Officials saw the huge warheads that deterred the Soviets as much less credible against today's far weaker adversaries. Leaders of nations such as North Korea or Iran, they argued, would be unlikely to believe a U.S. president would order even a retaliatory strike with arms that might kill hundreds of thousands.

Hobson's Choice

Early proposals from the administration to study new nuclear weapons met little congressional resistance. But in 2004 it ran into an unexpected foe: an Ohio Republican congressman named David Hobson, head of the House subcommittee that funds nuclear-weapons programs. He was critical of what he saw as poor security and management problems at the labs. But more than anything, he opposed a new nuclear bunker-buster.

"We can't tell other countries don't build any nuclear weapons, but we're so superior that we'd like a new weapon of our own," he says. Mr. Hobson has stared down both the administration and the nuclear labs' top congressional patron, Senate Energy Committee Chairman Pete Domenici of New Mexico, blocking funding for design of a bunker-buster that would put a harder case around an existing warhead.

At the same time, Mr. Hobson has become the leading proponent of building a new, sturdier replacement warhead, an idea pitched to him by Los Alamos scientists. He says it makes technical sense and would also help head off pressure to build new designs such as the bunker-buster. The reliable warhead "only replaces what we have -- there's no new mission," so it should be easier to explain internationally, he says. When the administration sought money last year to study weapons that would have new missions, he redirected the funds to what his staff dubbed the Reliable Replacement Warhead.

By spring of 2005, the administration's Mr. Brooks also had become a champion of the replacement warhead. He spoke of designing a new stockpile that was more reliable, less expensive, more environmentally sound and ultimately smaller.

He also made clear, in congressional testimony, that the administration set its sights beyond that. The reliable-warhead program, he said, would help create a flexible nuclear infrastructure able "to provide new or different military capabilities" if needed. And he pressed for funding to begin planning for a new plutonium-trigger plant, replacing Rocky Flats. This year, when the administration asked for $9.4 million to study the reliable warhead, Congress, at Mr. Hobson's urging, appropriated nearly three times that.

Exactly how new this warhead would be isn't yet clear. Teams at Los Alamos and at California's Lawrence Livermore Lab now are working on competitive designs. They've been told to design a warhead that has the explosive power of the W-76, but inside the larger body of a more powerful warhead, the W-88.

The end of the Cold War makes this possible, says Los Alamos's Mr. Martz. When the U.S. was packing 10 warheads on a single missile to confront the Soviet Union, the labs were told to design the most powerful warheads they could with the least size and weight. So they took risks, such as using the smallest possible amount of plutonium that would ignite a full thermonuclear explosion.

Not having to make a warhead so light gives designers more options. For instance, instead of surrounding the plutonium "pit" with beryllium, which is light but toxic and creates cleanup issues, they can use a heavier metal such as titanium or even stainless steel. They also can put in more-effective trigger locks, to make it harder for a terrorist who stole a warhead to set it off.

Mr. Martz says the freedom to make a heavier warhead could also include a heftier plutonium pit, to ensure the full explosion ignites. As a result, he believes -- though he won't guarantee -- that all these changes wouldn't require testing. He says he also can't guarantee there will never be a need to test older warheads to confirm their reliability.

Quiet Preparations

Outside Las Vegas, the government's Nevada underground test site is quietly preparing for such possibilities. The test site has stayed alive by doing its own share of virtual testing. Almost 1,000 feet below the desert floor, inside a maze of well-lit tunnels, engineers do "subcritical" experiments: compressing aging plutonium samples nearly to the point of a chain reaction to see how they perform.

Since the Clinton administration, the site has been kept three years short of readiness to conduct new tests. The Bush administration won funding to shorten that to two years.

Early next year engineers will lower a new plutonium trigger, made experimentally at Los Alamos, into a 600-foot hole, drilled in the 1970s. They'll then implode it, short of a nuclear explosion. The experiment will give crane operators their first practice in over a decade in lowering a test canister. Other technicians will get experience in feeding in diagnostic cables.

Such simulations lead some to wonder if this administration or a future one might use the reliable-warhead program as an excuse to resume testing or -- something now forbidden by law -- as an opening to build new military capabilities. "I don't trust this group....We have to be on guard," Rep. Hobson says.

Raffi Papazian, Los Alamos's lead engineer at the site, says he and his colleagues are aware the actions might be misread. "We've worked with the State Department" to explain to embassies there's no plan to violate the test moratorium, he says.